abstracts for
4 Coastal & Island Mines

The Department of the Interior (Department) is considering the desirability of issuing new regulations to govern postlease operations in the Outer Continental Shelf (OSC) for minerals other than oil, gas, and sulphur under the authority of the OCS Lands Act (OCSLA). Comments and recommendations are requested from interested parties. The Mineral Management Service will consider relevant comments in determining the conditions, benefits, costs, and probable consequences of such regulations.

On March 10, 1983, President Reagan proclaimed a 200 mile "Exclusive Economic Zone" off the shores of all U.S. states and territories. The proclamation was intended to secure for the U.S. Government the sovereign right to explore, exploit, and conserve natural resources. Subsequent to the proclamation, the Minerals Management Service of the U.S. Department of Interior proposed a lease sale to private companies for the right to sea-bed mine polymetallic sulfides in the Gorda Ridge area 100 to 200 miles off the coast of Oregon and Northern California. This paper documents and discusses the proposed lease sale and the technical and legal problems associated with the proposal.

Mining of metal-rich, deep seafloor sediments and concretions has become a technical reality during the 1970s and 1980s. Although present metal market conditions, uncertainties of the legal prerequisites, and a growing awareness of environmental risks have all slowed down ocean mining development, its eventual success seems unquestionable. The amount and quality of ores will ultimately sustain economic production.

The Red Sea deposits of metalliferous hot brines and sediments (Ag, Zn, Cu, Au) will be of particular economic, technological, and scientific value for Saudi Arabia and the Sudan, who jointly own this deep-sea resource. About 15 years of active exploration, environmental work, and mining development work have produced interesting results. The main technical, environmental, and economic outlines of this particular model case are presented and discussed. Conclusions and opportunities for ocean mining, an industry of the twenty-first century, are given.

The location of brine pools and metalliferous sediments along the median valley of the Red Sea is related to the distribution of probable transform faults within the Red Sea inferred from morphology, continental fracture lines and bathymetric data. The timing of brine activity (mineralization) within the Red Sea appears to be related to glacio-eustatic changes in sea-level. It is suggested that elevations in sea-level at the end of glacial periods promote the movement of sea water along fault zones and result in discharge of brines within the median valley.

The heat provided by volcanic activity on the floor of the median valley is considered to be unnecessary to heat the brines and to promote brine circulation; moreover, models for the origin of these deposits that suggest brines are discharged due to volcanic heat fail to explain the distribution and episodic nature of brine activity.

The discovery and detailed investigation of hot brines and metalliferous sediments in the Atlantis II Deep of the Red Sea, during the mid 1960s, revealed a potentially exploitable orebody in the process of formation. Following this discovery, investigations were made to find additional deposits of this type. The central trough of the Red Sea was surveyed by the Applied Geochemistry Research Group aboard the Nereus in 1970 and 1971, and by German scientists aboard the M. V. Wando River in 1969 and the M.V. Va/divia in 1971 and 1972. A geochemical investigation of cores provided by these subsequent surveys has revealed the variable nature and widespread distribution of metalliferous sediments in the Red Sea.

In this paper an attempt is made to explain the distribution of these deposits in relation to known structure in the Red Sea region, and to interpret the timing of mineralization (brine activity) in relation to the recent sedimentary history of the Red Sea. The controls n the timing and location of mineralization are considered to be important factors in the genesis of these deposits. Detailed knowledge of the distribution and genesis of the brine pools and metalliferous sediments will, it is hoped, provide guidelines for future exploration of these and related deposits formed in rifting environments.

Although motion between Arabia and Africa is presently occurring along the entire length of the Red Sea, the morphology and tectonics that result from this motion vary greatly along its length. South of 21 degrees N, the main trough is bisected by a deep axial trough which has formed by sea-floor spreading during the past 4 m.y. and is associated with large-amplitude magnetic anomalies and high heat flow. North of 25 degrees N, an axial trough is not present and the floor of the main trough has an irregular faulted appearance. The magnetic field in the north is characterized by smooth low-amplitude anomalies with a few isolated higher amplitude magnetic anomalies commonly associated with gravity anomalies and in many places probably due to intrusions. Between these regions, the axial trough is discontinuous with a series of deeps characterized by large-amplitude magnetic anomalies alternating with shallower intertrough zones which lack magnetic anomalies.

It is argued that the different regions represent successive phases in the rifting of a continent and the development of a continental margin. An initial period of diffuse extension by rotational faulting and dike injection over an area perhaps 100 km (60 mi) wide is followed by concentration of extension at a single axis and the initiation of sea-floor spreading. The main trough in the southern Red Sea, away from the deep axial trough, formed during the Miocene by the same processes of diffuse extension that are still active in the northern Red Sea. This model explains the available geologic and geophysical data and reconciles previous models for the formation of the Red Sea which emphasize either the evidence for considerable motion between Arabia and Africa or the evidence for downfaulted continental crust beneath much of the Red Sea.

The initial pre-sea-floor spreading stage results in considerable extension (160 km or 100 mi) at 25 degrees N n the Red Sea), can last for several tens of millions of years, and is an important factor in the development of the continental margin. Such an extended phase of rifting and diffuse extension must be taken into account in studies of sedimentation, subsidence, and paleotemperatures.

The presence of metalliferous sediments in certain deeps along the axial trough of the Red Sea has been known for many years but it was only with the setting up of the Saudi Arabian-Sudanese Red Sea Joint Commission in 1975 that serious attempts were made to explore the possibilities of commercial exploitation. A report of progress to date is given, attempts to develop a major sulphide deposit containing zinc, copper and silver at a depth of 2000 m under hot brine pools of the Atlantis II Deep being described. A method of mining the finely disseminated muds involving dispersion and dilution and then pumping to the surface was developed and tested with the dynamically positioned drill ship SEDCO 445 during the first quarter of 1979. Aboard ship the mined slurry was pumped to a flotation plant at a rate of approximately 6 m3/h for production of a bulk sulphide concentrate, with discharge of tailings to sea at depth. Currently, preference is being given to chloride hydrometallurgical methods of processing, briefly described, to recover metal values. The impact of mining and mineral processing operations on the sea and coastal environment has been of major concern, and extensive studies have been conducted by biologists in association with specialists in the other disciplines involved-for example, oceanography and hydrography.

Future plans for this unique deep-sea mining venture are outlined.

The Gulf of Aden has the features of a miniature Atlantic Ocean, namely a central rough zone, main trough and continental margins. It has probably evolved within the last 45 Ma, i.e. it is approximately one third the age of the Atlantic. Being youthful, it is a good place for studying the early stages of continental drift, sea floor spreading and evolution ofcontinental margins.

Sixteen precision depth, gravity and total intensity magnetic profiles have been obtained in the westernmost Gulf of Aden along the direction N 32/212 degrees, estimated to be the direction of sea floor spreading from the computer fit of Arabia and Somalia. In addition, a continuous seismic reflexion profile was obtained over the northern part of one of the profiles from the axial rift zone to the Arabian continental margin.

The reflexion profile reveals that the basement (sulface of oceanic layer 2) has at least three distinct slopes. Changes in the characters of the gravity and magnetic anomalies are noticed corresponding to the changes in slopes of the basement. In accord with recent ideas on the formation and cooling of oceanic lithosphere, it seems unlikely that the Gulf of Aden has evolved by continuous sea floor spreading and more likely it has evolved in at least three distinct phases. The earliest of these is difficult to date from the magnetic anomalies and three possible models are presented. The most likely indicates sea floor spreading from 0 to 4.5 Ma (Plio-Pleistocene), 16 to 23.5 Ma (latest Oligocene to lower Miocene) and 35.5 to 43 Ma (upper Eocene to lower Oligocene). The most Surprising result is that the seismic reflexion and gravity data require the ocean-continent boundary to be between the 100 fathom contour and the coast. This implies that the continental margins are underlain by early oceanic crust and should more accurately be called oceanic margins rather than continental margins.

Other disoveries include three previously unmapped transform faults and a jump in the spreading axis in the eastern part of the survey area. These, together with the locations of the recent spreading axes and a possible triple junction, are shown on a new tectonic map of the area.

The Atlantis-Il-Deep's metalliferous sediments were recently discovered along the mid-ocean ridge system extending into the Red Sea, at a mean water depth of 2,200 m. The average thickness is 7 to 11 m in different sub-basins. The metal-bearing mud contains sulfides of zinc, copper and iron with significant amounts of silver, gold and cobalt. A variety of oxide, siliceous and carbonaceous gangue minerals are also present.

To determine the in-situ characteristics pertaining to the variability of the metal grades and mineralized thickness, and to study the natural phenomena, mining geostatistics was applied to estimate the Red Sea offshore mineral resources. Horizontal experimental variograms were computed along 0 +180 degrees and then models were fitted to analyse the mineralization in each area. Kriging estimates indicate that 696.330 million tons of bulk sediments contain 1.891 million tons of zinc, 0.425 million tons of copper and 3.75 thousand tons of silver. Gold and cobalt contents were calculated from the analysis of solids in flotation concentrates as 47 tons and 5,368 tons respectively.

The significant outcome of implementing geostatistics to the Red Sea brine preciptates is not only for the evaluation of metal reserves, but it also provides a useful tool in the optimization of selective dredging of appropriate areas to be mined.

The occurrence of metalliferous sediments of the Red Sea has induced considerable scientific and industrial interest. The Saudi-Sudanese Red Sea Commission and its main contractor Preussag AG cooperate in exploring the deposits and developing new technologies to produce metals from the sediments. The main event of the project so far, has been a successful mining test performed in the Atlantis II Deep including concentration of the sediments and disposal of tailings. Two ships were involved in this operation from March to June 1979, SEDCO 445, the first dynamically positioned drillship in the world, serving as a test production platform, and VALDIVIA, the German ocean exploration vessel, performing environmental and geologic research and supply services for the test mining ship. Some 200 scientists, engineers and technicians from Arabic countries, Europe and the US took part in the operation, many more in the preparation and evaluation. This multinational project, encompassing many different technical and scientific disciplines, continues to generate new information on the natural history of the Red Sea and valuable know-how on technologies for raw material production.

A pre-pilot mining test for metalliferous mud in the "Atlantis II Deep" of the Red Sea has been undertaken successfully in Spring 1979. It could be shown that a continuous mining of mud from the deep sea bottom is technically feasible. About 15,000 tons of mud-brine mixture have been mined, 2,000 tons were processed to a concentrate of high metal contents.

The Red Sea unique environment has up to now been relatively unaffected by polluting consequences of Man's activities, except for evidences of oil along the coasts and reefs from transition ships, harbours, industrial and human waste with growing population and industrialization.

The discovery, in the mid-sixties, of deposits of metalliferous muds- rich in heavy metals, and the probable mining and processing of these was expected to add to the risk of pollution. The Saudi-Sudanese Red Sea Commission, entrusted with the development and exploration of these non-living resources, has already set out an environmental study programme, more or less directly related to the conservation of the living marine resources. Within this framework, the studies have emphasized the assessment and magnitude of the possible risks for the environment resulting from a tailings disposal in the Atlantis II Deep over an extended period of time and the development of methods to minimize the risks.

The results obtained so far, indicate that a well controlled tailings disposal below 1000 metre water depth would keep the environmental impact of such an operation in acceptable dimensions. But it is hoped that the forthcoming Pilot Mining Operation will be capable of clarifying some uncertainties through further computer modelling, monitoring a full scale tailings disposal test, using realistic input conditions and evaluation of the ecosystem.

Benthic metabolism and standing stocks were investigated in the deep Red Sea between 21 degrees and 27 degrees N. Activity was assessed by the determination of respiration rates with a shipboard method and by calculating oxygen consumption from the activity in the electron transport system. We attempted to compare results from different latitudes within the warm Red Sea and with data from cold Atlantic environments. Our investigations were part of an environmental risk assessment to evaluate future mining of metalliferous sediments from the Atlantis II Deep.

As one of the youngest oceanic zones on Earth - an ocean in the making - the Red Sea is of enormous interest in understanding structural and tectonic phenomena related to ocean floor spreading and in reconstructing the history of the global tectonics. In addition, in the last twenty years metalliferous deposits have been discovered in the Red Sea. Their study should lead to a better understanding of processes of metal concentration and to useful guides in the exploration for new deposits, such as those associated with old oceanic formations.

The proposed rules would apply to prelease prospecting activities for marine mining. Marine mining is the recovery of minerals other than oil, gas, or sulphur within the Outer Continental Shelf (OCS) of the United States. The rules are intended to regulate such activities, protect the envfironment, and provide for Minerals Management Service (MMS) inspection of the activities and access to the resulting data and information. The rules would be the first in a series of rules implementing a comprehensive leasing and regulatory program for minerals other than oil, gas, or sulphur within the OCS.

This report is a summary of foreign offshore mineral development activities. Over fifty countries are discussed separately in terms of offshore exploration and development for commodities such as sand and gravel, phosphorite, placer tin, diamonds and gold on their continental shelves. Within each commodity section, the extent of activity is noted along with the companies involved.

It is concluded that offshore mineral development is an established industry and that many countries are turning towards their offshore areas for potential mineral sources. It is recommended that countries omitted in this report be researched and that the information be compiled to provide a complete global overview.

This report investigates mining concepts for pollymetallic sulphide occurrence off the west coast of Canada and their development related properties. Existing deepsea mining technology is reviewed, evaluated. The deposits are still in the early stages of scientific investigation. They represent a long term development opportunity, but at the moment no suitable mining system exists, although it is believed one can be developed if the need arises. It is recommended that exploration be continued on all areas, with future work taking into account both scientific and engineering needs.

Advancement in deep-ocean mining technology is a great challenge not only for the resource exploitation, but also for scientific exploration. Future petroleum exploitation will benefit from this advancement. This paper reviews research, development and design aspects of recent technologies for deep-ocean mining systems to recover manganese nodules and cobalt-rich manganese crusts from the seafloor at 800-6,000 m depth. First, the seafloor crust is characterized on the basis of preliminary data from the recent survey in the Pacific Ocean. In the last 10 years, few significantly new technologies appear to have evolved in the nodule mining system. However, subsystems have been designed and tested systematically in Japan. Progress has been made in the seafloor miners (or collectors), hoisting systems, and pipe deployment and retrieval dynamics, materials, the system integration, and integrated system control. There was no at-sea test of any deep-ocean mining system since the 1970's. For the crust mining, the seafloor survey has been conducted in some locations of the Pacific Ocean, and the physical characteristics and properties of only a fraction of the crust samples are tested, and more extensive survey is required at various locations of the Pacific to determine its distribution, abundance, and physical characteristics. The United States has a greater geological emphasis, while Japan has a greater engineering emphasis. Also, two crust mining system concepts are discussed. The deep-ocean submersibles will play a role in the ocean mining. Only Japan and India are currently active in the ocean mining program. Japan's national program has been preparing her first at-sea nodule mining testing in 1997. Until commercial mining operations of manganese nodules begin, the mining systems are expected to be continuously updated with the advancement of new support echnologies. For the crust mining, the technical challenges are yet to be defined. This review updates that of Chung (1985).

Cobalt-rich manganese crusts occurring within the 200 mile Exclusive Economic Zones (EEZs) of Pacific island nations may be of long-term strategic importance to the major industrialized nations and represent an important long-term development option for Pacific island nations.

A resource assessment methodology is described and used to estimate the resource potential of cobalt, copper, nickel and manganese within the EEZs of the Hawaiian Archipelago, Johnston and Palmyra Islands. Results of this study indicate a resource of roughly 10 million tons of cobalt, 6 million tons of nickel, 1 million tons of copper and 300 million tons of manganese within the study area.

Available data on manganese crusts and ocean bottom topography is inadequate for undertaking a full assessment of the resource potential of crusts within the EEZs of most Pacific island nations. Therefore it is recommended that to evaluate the potential of these nations a comprehensive research programme should be developed and implemented.

A comprehensive and authoritative study of sediment plumes generated by marine aggregate mining operations in the UK has been completed. A thorough literature review has identified, with some notable exceptions, a paucity of conclusive information applicable to the marine aggregate mining industry in general and in particular to the UK situation. Information is more widespread for other forms of dredging activities but is shown to be largely inappropriate for general application to most marine aggregate mining scenarios.

Extensive sampling campaigns have determined the sediment source terms of benthic and surface plumes. These support earlier (unpublished) results and are corroborated by other contemporary studies world-wide. Marine aggregate mining vessels currently working in the UK are shown to return, as overspill and unwanted screened material, between 0.2 and 5 times the cargo load. Further, the importance of detailed prospecting and reserve evaluation data is reinforced for predicting the likely magnitude and variation or such overboard returns.

Baseline measurements of the range of increased turbidity that may be generated have been obtained. A total of 162 Continuous Backscatter Profiling (CBP) transects across plumes have been recorded and post-processed using in-house programs. CBP transects show the bulk of the plume settling out of the water column (or, more strictly, settling to within 1.5m of the seabed) within 300m (sands) to 500m (silts) downstream. This corresponds to a time period of 10-15 minutes since release. Coarse sands (> 2mm) and gravels settle out virtually instantaneously. We propose that the far field visible 'plume' extending beyond the boundaries of measured suspended sediment load discernible above background conditions is an organic admixture of fats, lipids and carbohydrates agitated by the dredging process and with little sediment content.

We recommend as Best Practice that assessments of plumes from dredging operations are founded on pertinent, well designed sampling and testing programmes. We have shown there are significant productivity gains through the competent use of Continuous Backscatter Profiling (CBP) techniques with precise navigational control to effectively track and delimit the plume boundaries. This significantly improves confidence in the interpretation of results as representative or the maxima and minima conditions.

The development of a benthic plume by the hydrodynamic and physical interactions of the draghead on the seabed has been firmly established by the present work. We have shown however, using underwater imaging suspensate sampling from around the draghead and CBP techniques, that the magnitude of the draghead plume is minor in comparison with the surface plume. Contribution of the overhead returns to the suspended load is 4-5 orders of magnitude greater than from the draghead. It is considered that the impact of the draghead plume may be deemed negligible in comparison to any surface plume effects.

Hopper overflow and the screening process is thus of dominant importance in the establishment of dispersive plumes from marine aggregate mining. Plume excursion is dependent on (among other factors) the total quantity of sediment rejected, the particle size of the sediments and tidal current velocity. Further, the rate and manner of overboard return is important in defining the initial stages of plume descent as a density current (Dynamic Phase) which subsequently controls the location and quantity of material available for conventional advection and dispersion (Passive Phase). Our work confirms that, as a general principle, the rate of deposition of material from the dispersing plume is much faster than would be assumed from conventional Gaussian diffusion models and that sedimentation is largely confined to distances of a few hundred metres from the point of discharge.

Importantly this suggests that the impact of dredging on benthic biological resources may be confined to the immediate vicinity of the dredged area. Little is known of the impact within Licence areas worked commercially, in the surrounding deposits, nor of the rate of recovery following cessation of dredging. Of particular interest is the possible impact of organic material released into the water column which may play an important role in the (well-documented) enhancement of secondary production in deposits surrounding dredged areas. This requires further investigation both as part of our understanding of plumes associated with marine aggregate mining and with establishing the impact on biological food webs leading to commercially exploitable fish stocks.

This information will allow scientific fact to replace poorly informed speculation and unwarranted allegations of permanent damage to the seabed and benthic environment. Knowledge of such information will enable competent and authoritative monitoring programmes to be emplaced and workable mitigation measures to be developed. Unnecessary sterilisation of useable resources may justly be avoided.

Ferromanganese crusts on raised areas of the ocean floor have joined abyssal manganese nodules and hydrothermal sulfides as potential marine resources. Significant volumes of cobalt-rich (about 1% Co) crusts have been identified to date within the U.S. Exclusive Economic Zone (EEZ) in the Central Pacific: NW Hawaiian Ridge and Seamount region, and seamounts in the Johnston Island and Palmyra Island regions. Large volumes of lower grade crusts, slabs and nodules are also present in shallow (<1000 m) waters on the Blake Plateau, off Florida-South Carolina in the Atlantic Ocean. Data on ferromanganese crusts have been increased by recent German and USGS cruises, but are still sparse, and other regions having crust potential are under current investigation.

A study of the fish populations within the surf zone and over the first and second reefs off Hallandale (Broward County), Florida, was conducted, 7 years following dredging for a beach restoration project. This study utilized an observational and recording technique adapted from Jones and Thompson (1978). The data were compared with those of an earlier study conducted in 1971-72.

In the 1971-72 study, conducted during and subsequent to dredging activities, 42 species of fishes belonging to 24 families were found. The present study revealed the presence of 114 species of fishes belonging to 36 families. The dusky jawfish (Opistognathus whitehursti) common along the first reef platform in 1971-72, was found to be absent. The absence of this fish is attributed to an alteration of the substrate on the first reef by incursion of fine sediments. Damage to the second reef observed during 1971-72 was not evident during this study.

The animal assemblages associated with three rock samples from depths exceeding 50 fathoms are described and discussed. It is shown that rock-bottom faunas are very uniform from low-tide mark to at least 110 fathoms. Reasons for the wide benthic distribution are discussed.

Introduction

In March 1983, President Ronald Reagan proclaimed the mineral resources of the ocean floor, located within 200 nautical miles (nmi) of American soil, to be under jurisdiction of the U.S. Government. This proclamation of a U.S. Exclusive Economic Zone (EEZ) led the way for the establishment of regulatory regimes to direct the exploitation of hard mineral resources within these areas.

Cobalt-rich crust deposits in the EEZ are known to occur around the Hawaiian Archipelago and Johnston Island, and the Minerals Management Service of the U.S. Department of the Interior has joined with the State of Hawaii Department of Planning and Economic Development (DPED), to examine the possibility of future exploitation of these crusts. The result of this cooperative effort is an Environmental Impact Statement (EIS) which evaluates the potential impacts of the exploration, mining, and processing of these cobalt-rich deposits.

Because of the numerous local issues potentially raised by the establishment of a marine mining industry in Hawaii, MMS has elected to have this BIS assembled under joint Federal and State supervision. The effort is monitored by a Task Force composed of individuals from government and academic agencies with interest in various aspects of the EIS.

The fundamental questions which must be addressed in this project include the following:

1. Is there or will there be in the near future a genuine need to mine this potential resource?
2. Does an economic resource exist?
3. What would be the basic characteristics of the mining industry?
4. Which natural and human environments are most likely to be affected by this industry, and what are the magnitudes of these effects?

The answers to tese questions are the essence of the EIS, and the basis for subsequent Federal action in the area.

This document provides an objective answer to question 3, prepared by a group of experts in fields of mineral resource assessment, mining technology, metallurgical processing, and logistical support for such a mining operation, and based on presently available information.

Resource Assessment

The existence of cobalt-rich ferromanganese oxide crusts on the Pacific seamounts has been recognized for at least 20 years, and has most recently been studied by survey teams from the U.S. Geological Survey, the University of Hawaii, and a West German consortium. The surveys in the Hawaiian and Johnston Island EEZs have been preliminary rather than exhaustive. However, they do indicate the existence of a potentially exploitable resource large enough to justify the preparation of an Environmental Impact Statement (EIS).

The results from these surveys support a resorce assessment based on the following model for crust occurrence and distribution:

1. The permissive zone for crust occurrence is on seamount areas between the depths of 800-2400 meters (m). The study areas are shown in Figure 2-1.
2. Crust thicknesses vary with age. Based on the present state of knowledge, there are two generations of development: an older crust generation formed at a rate of about 4.8 millimeters per million years (mm/my) between 9 my and 16 my ago and a younger generation which formed at a rate of about 2.7 mm/my during the period 8 my ago to the present. The period 8 my to 9 my was marked by phosphate deposition. The maxium average conputed crust thickness is 5.52 cm for the Hawaii EEZ and approximately the same for the Johnston Island EEZ. Averages for individual areas vary depending on the age and location.
3. Crust coverage within the permissive zone ranges from 0% (areas of thick sediment cover) to 100% (areas of thick crust "pavements"). From available information it appears that Hawaiian ridge deposits have average coverages of bout 25%; other deposits in the study areas average 40%.
4. The average weight density for the crusts is estimated at 1.95 grams per cubic centimeters (g/cm3) for wet crust and 1.34 g/cm3 for dry crust. Metal concentrations presented here are for the dry crust.

The estimated metal concentrations and resource potential in the study area are summarized in Table 2-1; for the areas which may be offered in the initial lease sale, they show an overall in-place resource potential of 2.6 million tonnes (t) of cobalt, 1.6 million t of nickel, 58 million t of iron, and 81 million t of manganese. (Note: the unit "tonne" refers to a metric ton and is abbreviated "t".) The area labeled "excluded" will be omitted from any initial lease sales held by the U.S. Department of the Interior. These areas were excluded to avoid potential conflicts with sensitive wildlife resources and military activities. The assumptions used to make these resource estimates are described in §3.1 and §3.2. Before an actual mining operation could be initiated, more detailed assessments with appropriate tools, including both photographic and physical recovery means, would be needed to support the required financial investment.

The Resource Assessment chapter (§3.0) also presents data on the seamount morphologies and the physical oceanography of the Hawaiian area. Indications are that the slopes of the seamounts are not too steep for mining and that the current and wave conditions would not cause any difficulty with a mining operation except at the time of an occasional severe tropical storm.

Mining System

The candidate mining system has been sized to deliver approximately one million tonnes of wet manganese crust per year to the processing plant. Present knowledge of the microtopography of the sea bottom on the seamountsand on the nature of the bonding of the crust to the substrate is too preliminary to allow for an optimized design of a mining system. Previousexperience with ocean floor mining (notably the work on manganese nodules in the Clario-Clipperton Fracture Zone) and engineering reasoning indicate that a probable system will consist of a controllable bottom-crawling tracked vehicle attached to a mining ship on the surface by a hydraulic pipe lift system and an electrical umbilical cable, as illustrated in Figure 2-2.

A major difference between mining of manganese crust and nodules or other ocean minerals is the manner in which the crust must be removed from the substrate. For the base-case mining scenario adopted here, technology similar to that used for surface continuous coal mining was assumed, whereby a thin layer of crust would be "stripped" from the seabed using rotary cutting tools. This is an unconventional method for ocean dredging, and increases the level of engineering sophistication required for a manganese crust miner design.

Allowance for bad weather, system maintenance, and other lost productive time leads to a conservative estimate of 206 operational days per year (d/yr) as a basis for sizing the miner.

A crucial factor for the economics of the mining operation and the resulting environmental impact is the amount of substrate that must be dealt with in addition to the crust. The preliminary resource assessment shows that the crust thickness and coverage are quite variable and that the strength of the attachment of the crust to the substrate depends on the particular underlying material. Ideally, it would be optimum to convey only pure crust material to the surface ship, but this is highly unlikely for first generation systems. The miner will have to cut, gather, crush, and may partially separate the ore before it is lifted to the surface. Various estirnates have been made as to the fraction of substrate material which will be entrained in the seafloor collector, ranging from 25-50% of the recovered ore (20-42% after shipboard dewatering) The base-case scenario assumes the recovery of 25% substrate in the ore.

The amount of bottom disturbance and the resulting plume of suspended sediment in the neighborhood of the miner will dpend on the nature of the fragmentation process used to separate the crust ore from the sea bottom and on the ability of the miner to follow closely the actual contour of the local sea bottom. Clearly, there will be considerable distance near the miner, which will interfere with any benthic population that may be present.

The most environmentally significant potential failure of the mining system is likely to be the loss of power to the lift system, causing a backflow and discharge from a dump valve 25-30 m (83-165 feet (ft)) above the seafloor. The contents of the lift system would be on the order of 30 t of solids.

The occurence of such a failure would be a very rare event, and, in any case, the solids would settle rapidly with only a few pecent being fine enough to travel any distance. Other subsystem failures, such as those which might occur on the bottom miner, would not have any environmentally significant effects.

Metallurgical Processing

Once the ore has been mined, it must be processed metallurgically to recover the desired minerals in their appropriate product form. At prevailing commodity prices, and based on current knowledge of the resource, ferromanganese oxide crust of the Hawaiian Archipelago is perceived as a cobalt ore with significant by-product nickel and lesser by-product values of copper, zinc and perhaps platinum. Cobalt grade of the crust, when fully separated from substrate, is appreciably greater than the average cobalt grade of presently exploited world resources, in which cobalt almost invariably occurs as a by-product value. Although manganese is a major constituent element of the crust, it is questionable whether it can be economically recovered in moderate to high yield (as ferromanganese). An overriding general consideration is that ample land-based resources and production capacity exist for all of the value minerals of the crust, although the United States is not well favored in this respect. If the Hawaiian and Johnston Island crust deposits are to be exploited in the near fture, the basic justification (in the absence of supply or price disruptions) may initially be on the grounds of U.S. strategic needs rather than on economic gain.

Assuming that such a case is made, it is possible to proceed with the broad outline of an appropriate processing activity. Optimizing of a specific processing method is impossible at this stage because of the preliminary nature of the characterization of the natural resource. The general components of a workable process can be defined in sufficient detail to indicate the major environmental implications; this is the major requirement for the mining development scenario input to the EIS.

In general terms, there are two ways of extracting the minerals from the ore; namely, by a smelting (pyrometallurgical) procedure or by a hydrometallurgical process involving leaching of the ore. A candidate version of each general process was selected on the basis of high potential cobalt yield and amenability to production of a process, intermediate or concentrate, for refining in Hawaii or for shipment to a metals refinery located elsewhere, as conditions dictate (Figure 2-3). Preliminary process analyses indicate removal of pore sea salts to be important and separation from co-mined substrate to be essential for efficient utilization of known extractive metallurgy applicable to the crust. The matte smelting process provides for water removal by drying and roasting of the beneficiated ore and entails appreciable consumption of fossil fuel for that and other process purposes. In addition, the electric smelting furnaces consume major quantities of electricity, especially if co-product ferromanganese is produced. This factor is an obvious concern for an economy largely dependent upon imported petroleum for power generation. Given the availability of less expensive geothermal or Ocean Thermal Energy Conversion (OTEC) electricity, the attractiveness of the pyrometallurgical route would be improved. Moreover, the principal process waste is a vitreous slag that would likelybe sufficiently inert to find use as fill or aggregate or, at the minimum, to allow for relatively clean disposal, perhaps at sea.

The sulfuric acid pressure leach process (hydrometallurgical alternative) is more moderate in its electricity consumption but would lead to greater consumption of fresh water for process uses. Moreover, the voluminous major process waste, consisting mainly of leach residue and gypsum tailings, would impose significant disposal requirements in terms of land area and reclamation as well as containment and monitoring procedures. If a major portion of the process steam and water requirements could be obtained economically from the indigenous geothermal resource, the attractiveness of the hyrrometallurgical alternative would be enhanced.

For the desired throughput of a million t/yr (wet-basis) of crust, treated by either of the candidate metallurgical processes, a considerable amount of land will be required. The metallurgical complex, including space for on- land disposal of solid wastes for 20 years of normal operations, will require from 300-600 acres of land for the pyrometallurgical process, and from 500-900 acres for the hydrometallurgical process, including dedicated sulfuric acid production. Approximately 450-600 personnel, of all categories, would be employed in the industrial complex.

As in any major industrial facility, the crust processing plant will involve large quantities of solids, gases, and liquids, presenting various degrees of hazard. The design methods and industrial safety practices for dealing with these conditions are well known and have proven effective when properly implemented. Based on extensive industrial experience, the estimated occurrence of accidental releases from the proposed installation as a result of equipment failure would be on the order of one in a thousand to one in a million per year.

The plant will also generate local noise from the various machinery on the property. The allotted space should keep the noise level at the plant boundary down o 50-60 decibel (dB) (equivalent to light traffic at a distance of 30 m) for the hydrometallurgical plant or to 55-65 dB (equivalent to traffic near a busy freeway) for the pyrometallurgical plant.

Transportation and Ports

Each phase and stage of a manganese crust operation has unique tranportation requirements. These are diagrammatically presented in Figure 2-4. At the outset, small research vessels are needed to locate and describe promising crust deposits. Such vessels are regularly used by university and industrial organizations and are available for charter. They need to be outfitted with various specialized tools such as side-scanning sonar, underwater cameras, sampling dredges, navigational aids, and other oceanographic equipment.

They would typically operate for a month's cruise, and their modest size (about 500 t) would place no unusual demands on shore facilities nor create any particular environmental hazards. Once a suitable ore body has been found, an intermediate size class of exploration ship (less than 2500 t) would be called upon for precise bathymetric definition of the mining site, and for more detailed geological and metallurgical characterization of the ore. Ships of this nature would probably also be chartered from existing operators, and would be equipped with specialized equipment through the use of instrumentation and laboratory vans. Ships of this size pose a slightly higher environmental hazard from fuel spills, waste overflow, or accident at sea, but a number of such oceanographic research ships are already operating successfully in compliance with all regulatory and operational standards.

With the advent of the mining ship, the potential impact on the environment becomes more significant. To handle the postulated throughput of a million tonnes of manganese crust per year, plus co-mining of unavoidable substrate, a mining ship of 65,000 deadweight tonnes (dwt) with diesel-electric power propulsion and a capability of dynamic positioning is required for proper control of the bottom iner. The mining ship on station would be complemented by two or more bulk cargo vessels of perhaps 23,000-33,000 dwt to take the mined ore and substrate to the shore-based processing plant. Alternative transport, such as barges, is also possible. Any potential for removing substrate at the mining site or for processing the ore at sea could have a strong positive effect on the economics of the operation, but these refinements may not be possible in the first generation system. Both the mining and the transport ships will place significant demands on harbors, docking facilities, and supply capabilities in the selected port area. Transfer of the raw material at sea on a routine basis also requires special attention to environmental protection. However, severe sea conditions are not likely to handicap the operations in the chosen mining areas.

Port facilities required for the mining operation can be considered in two aspects. First, the overhaul, supply, and home-porting needs of the ships involved, and second, the actual transport of the crust and co-mined substrate to the processing facilities. The prospecting and exploration vessels should not impose any special burden on existing facilities. The mining ship, though quite large, will not need frequent servicing (perhaps one docking per year), and could use facilities outside of Hawaii (U.S. West Coast or perhaps Japan). More exotic solutions such as a single-point buoy for offshore unloading of the slurried crustal mixture are also possible. Large quantities of consumables for the processing plant will be brought in by sea including such materials as gypsum, coal, diesel oil, coke, and probably sulfur. Some of these can be handled within the framework of the existing Hawaiian container trade between the Islands and the U.S. mainland.

A final problem is the inland transport of ore from the port to the actual processing plant since it is unlikely that the plant will be at the water's edge for acceptable Hawaiian locations. The alternatives for inland transport inlude rail, trucks, and conveyor and slurry pipelines.

A summary of the activities defined in the mining development scenario and selected as the base-case for the EIS is given in Table 2-2. Other options for each component of the scenario are discussed in this volume.

A review of the issues related to coastal erosion and conflicts with the fishing industry resulting from marine sand and gravel extraction was carried out in the United Kingdom. The study also reviewed the management and regulatory procedures for administering the marine sand and gravel industry.A number of the concerns expressed in the U.K. could potentially develop in Canada should marine mining increase from present levels. These issues were grouped into the following four categories:

1. Coastal Erosion
   • changes in wave refraction;
   • removal of protective bars;
   • changes in sediment transport patterns; and,
   • changes in residual sediment types.
2. Impact on Fishing Operations
   • marine disposal of debris, especially screens;
   • vessels operating outside of the terms of their licence;
   • vessels arriving unannounced and interfering with fishing operations;
   • permanent or temporary displacement of local fishing industry by extraction operations.
3. Fisheries Resource, Habitat and Other Environmental Concerns
   • potential destruction of spawning grounds and/or critical fish habitat;
   • alteration of the seabed to the detriment of subsequent recruitment of benthic organisms and fish species;
   • avoidance of sediment plumes by migrating species.
4. Administration and Management
   • lack of communication and information exchange between sand and gravel and fishing industries;
   • lack of procedures for the fishing industry to have direct input into the regulatory review process;
   • lack of basic information on both surficial geology and the biological and fishery resources.

The report concludes that a lack of communication between the fishing industry and the sand and gravel industry in the U.K. was a primary cause of many of the issues and recommends a number of procedures in Canada to improve the information exchange between the two groups. Another major issue in the U.K. was the need for information on the biological and geological resources. A similar lack of information exists in Canada and suggestions to improve this situation are included.

1. Applications to undertake activities that may have an impact on the fishing industry should allow for input from the fishing industry and an exchange of information. If prospecting areas are issued on an exclusive basis, then industry would be less sensitive to the confidentiality of location, which would promote the exchange of information.
2. All sand and gravel extraction licence applications should be reviewed by appropriate coastal scientists to determine the potential for coastal erosion or damage to shoreline structures.
3. The review process for mining licence application should include opportunities for other interests, particularly those of the fishing industry, to present information directly, as well as being represented by government fisheries personnel. The process should also ensure an appeal mechanism.
4. Appropriate or relevant environmental information to be included with each application fox, a licence to remove sand and gravel should include summaries of current and wave information and fishing utilization records.
5. Direct lines of communication should be established between the dredging companies and the fishing industry, both at the licence application stage and during production. Notice of changes in location by a dredging vessel should be given in advance by a minimum of two days.
6. The final authority in issuing a licence should be at "arms length" from the setting or collection of royalties.
7. Methods should be developed to ensure compliance with the terms and conditions of the prospecting and production licence. This would include:
   • accurate positioning systems and instrumentation which will record position, time and operational information (e.g., suction pumps) for subsequent inspection;
   • identification marks on all parts, particularly screens, that could be jettisoned offshore, plus manifest forms recording the movement to and from the offshore of these parts.
   • regular, but unannounced inspection of cargos and records to ensure quantities taken are within the conditions of the licence.
8. Monitoring should be carried out periodically throughout the life of the production permit to record changes in surficial geology and bathymetry, to ensure that the bottom material remains similar to its original character.
9. If required, an objective compensation board should be established to expediently review compensation claims and make awards.
10. Information on the distribution of sand and gravel resources, particularly in the nearshore (out to the 30-metre contour), is urgently required to help managers identify alternative sources.
11. Environmental studies on the longer-term impacts of aggregate extraction should be carried out, particularly on the effects of substrate alteration on recolonization rates and species, and on the effects to a commercial fishery of extended dredging activities.

The visit was for exchange of information and ideas based on the 30 year seabed R&D by each of the participants. Bibliographies were exchanged (about 700 references each) and arrangements made for future mutual updating. Microcomputer Systems for literature searches and data processing are not currently compatible, and cannot be combined without some software development. However, raw environmental data obtained by each agency can be processed by the other (using different software and analytical concepts). The two groups will continue their report exchanges.

HT's laboratory is starting to apply a very versatile data processing and analytical software package (COMM). It allows use of a variety of diversity, similarity and ordination measures. If the Canadian SIGTREE/COMTREE software for significance testing can be integrated with it, it will be the state-of-the-art software currently needed for seabed environmental R&D. Some follow-up work by an experienced Canadian user of SIGTREE/COMTREE should be able to accomplish this.

Lists of species demonstrated by both groups as recolonising impacted seabeds were exchanged, and others will be exchanged in the near future when prepared in manuscript form. DE will explore underlying taxonomy to demonstrate whether certain genera should be targetted as recolonisers, and bioengineered reclamation practices developed for them.

HT has developed a proposal for environmental monitoring of the next deep sea mining test or pilot operation. This is a project in which Canada should participate, and to which DE can contribute. It is recommended that Canada participate by funding at the appropriate time; and that the University of Victoria (Centre for Earth and Oceans Research together with the Centre for Environmental Health) be the Canadian partner. The joint project could include scholarships for a graduate student from each university to undertake thesis research in both laboratories as appropriate.

Manganese nodules have been recovered from about 130 localities in an area of about 2,500,000 km2 in the Cook Islands region, where they rest largely on red clay, and this paper relates their characteristics to their location.

Nodules from the Manihiki Plateau have an average grade (Ni+Cu+Co) of 0.98%, but their abundance is unknown. Nodules from the Samoan Passage have an average grade of 0.88%, and unknown abundance. Nodules from the Samoa Basin have an average grade of 0.67% and variable abundance. Nodules from the Southwest Pacific Basin have an average grade of 1.07%, and variable abundance; maximum nodule concentration is 35.2kg/m2. Nodules from the South Penrhyn Basin have an average grade of 0.99%, and variable abundance; maximum concentration exceeds 35kg/m2. Nodules from the North Penrhyn Basin have an average grade of 1.18% and a low abundance; maximum concentration is l0.7kg/m2.

In no case were nodules of potentially economic grade (>2% Ni+Cu+Co) found in potentially economic concentrations (>l0kg wet nodules per m2). The most prospective basins appear to be the South Penrhyn Basin (maximum grade 2.02%), and the North Penrhyn Basin (maximum grade 2.10%). In both basins the highest grades correspond to low concentrations. For concentrations exceeding l0kg/m2, the highest grade is 1.34% in the South Penrhyn Basin and 1.15% in the North Penrhyn Basin. In the two basins all grades exceeding 1% lie between 5000m and 5600m. In the South Penrhyn Basin all concentrations exceeding l0kg/m2 lie between 4800m and 5300m. There is a direct relationship between the grade and the Mn/Fe ratio.

Planktonic organisms are widely believed to provide much of the Ni and Cu in deep-sea nodules. Metals are concentrated in their tissues and skeletons and released during dissolution. The released metals may then be incorporated into noules. Thus the relatively low Ni and Cu grades of Cook Islands nodules, as compared to the nodules of the eastern equatorial Pacific, may result from the relatively low organic productivity of the surface waters. However higher grades may be present locally if metal-rich solutions have been escaping from active fracture zones.

Future nodule prospecting should concentrate on the Penrhyn Basin, in water depths of 5000m to 5600m, where high nodule concentrations and grades may occur together. Other possible prospecting guides include proximity to fracture zones, and proximity to bottom currents which are important for a variety of reasons.

Manganese nodules have been recovered from 160 of 285 deepwater stations in an area of about 9,000,000km2, extending from 168oE to 149oW and from 6oN to 10oS. About 25% of this region lies vithin 200 nautical miles of the islands of Kiribati. Kiribati consists, from west to east, of the Gilbert, Phoenix and Line Island groups, all of which are atolls topping volcanic chains and surrounded by deep basins. The Melaneslan Basin lies west of the Gilbert Islands, the Central Pacific and North Penchyn Basins lie between the Gilbert and Line Islands, and the Northeast Pacific Basin lies east of the Line Islands.

Nodules occur in all the basins. Maximum nodule concentrations (kg/m2) and grades (Ni+Cu+Co%) are 56.4 and 1.58 in the western Central Pacific, 31.6 and 3.55 in the eastern Central Pacific, 5.63 and 3.22 in the Northeast Pacific, and 10.69 and 2.23 in the North Penrhyn Basin. In the Melanesian Basin there are few data, but the maximum known grade is 1.47%.

A latitudinal zonation in nodule concentrations and grades is clearly apparent in this and the Cook Island region to the south. Maximum concentrations are at 5 degrees N, 5 degrees S, 11-15 degrees S and 23 degrees S, with minima at the Equator and 8 degrees S. Maximum grades are at 1-6 degrees N and 1-5 degrees S, with minima at the Equator and from 10 degrees to 25 degrees S. The latitudinal zonation is here attributed to the contrast between the equatorial one of high plankton productivity and the southern tropical low productivity region. High plankton productivity increases carbonate sedimentation rates, resulting in low equatorial nodule concentrations. The plankton provide abundant Ni and Cu for incorporation into the bottom sediments as the organisms dissolve, so metal grades in the broad equatorial belt are generally high. The narrow equatorial zone of lower gades is probably related to depression of the carbonate compensation depth, the depth at which carbonate is dissolved, which means that the valuable metals ore retained in the bottom sediments rather than migrating into nodules.

This study has shown that features which favour high nodule concentrations and/or metal grades are:

1. Water depths of 5000-5600m
2. The presence of Antarctic Bottom Water
3. Siliceous ooze or red clay substrate
4. Latitudes of 1-6 degrees N and l-7 degrees S.

Particularly favourable areas are the northeastern and southeastern Central Pacific Basin and the southern Melanesian Basin. Other areas which merit more work are the North Penrhyn Basin and the southwestern Central Pacific Basin.

The major conclusion of this paper is that nodules of potentially economic concentration (>l0kg/m2) occur in the same areas as nodules of potentially economic grade (>2% Ni+Cu+Co) in the eastern Central Pacific Basin. The existence of nodule grades of 3.55% in the eastern Central Pacific and 3.22% in the Northeast Pacific Basins in the Kiribati region is particularly encouraging. The data presented here clearly justify more nodule cruises in the region, and allow target areas to be properly defined.

This study of the Western Samoan offshore region has made use of 30 nearshore sample descriptions and 100 offshore sample descriptions - all the data available from a variety of sources including 65 CCOP/SOPAC stations. The land area of the Samoan islands is about 3000km2, and the marine area within the 200 nautical mile limit is about 150,000km2, so offshore resources are of great significance. The volcanic islands are aligned WNW and have steep flanks dropping down to abysmal plains to the north and south at 4000-5000m. In the southwest is the Tonga Trench whose maximum depth exceeds 8000m.

Samoa's offshore sediments have a variety of sources - volcanic eruptions, nearshore erosion, reef and nearshore benthos, and pelagic organisms - and hence are highly variable. On the island slopes and offshore banks may be found volcanic and limestone outcrops, calcareous pavements, volcanogenic and biogenic silts, sands and gravels, and calcareous oozes. Some phosphatization of sediments, and some manganese-phosphate pellets, have been recognized on offshore banks and on one seamount, but the available data indicate that phosphorite deposits of economic significance are most unlikely to exist.

The sediments of the abysmal plains, where any significant manganese nodule fields would have to be sought, consist of turbidite sequences with greater or lesser pelagic components depending on their position. Calcareous oozes are significant in the northwest, and siliceous oozes in the northeast. Manganese nodules are rare, and have low grades of valuable metals. The rarity of the nodules is ascribed to the high sedimentation rates caused largely by the rapid influx of volcanic debris. The low grades of nickel and copper are ascribed to the generally low production of the plankton which appear to be their major source elsewhere, and to the fact that the abyssal plains are generally well above the carbonate compensation depth so that the calcareous plankton are not dissolved and hence can not release their metals into the bottom sediments for concentration in manganese nodules.

A total of 91 archibenthal and abyssal species can now be recorded from New Zealand coastal seas, 42 of them not previously known from deep water, and 32 of them new to the fauna. Six families of asteroids are recorded for the first time from New Zealand-namely, Benthopectinidae, Pterasteridae, Korethrasteridae, Solasteridae, Brisingidae and Zoroasteridae. Genera not previously recorded from New Zealand are: Plutonaster, Dipsacaster, Benthopecten, Cheiraster, Anthenoides, Pseudarchaster, Hippasteria, Pteraster (sub-genus Apterodon), Peribolaster, Crossaster, Brisingenes, Zoroaster, Cosmasterias, Amphiodia, Ophiuraster, Ophiuroglypha, Paramaretia; also Aspidocidaris, a sub-genus of Goniocidaris. The deep-water fauna includes species restricted to New Zealand as well as species occurring in the north Pacific, Hawaii, Indonesia, south-east Australia and the Southern Ocean (Indian Ocean and Antarctic). It is interpreted as a mingling of endemic and cosmopolitan elements, shelf-forms occasionally descending the continental slope, and abyssal forms occasionally reaching the shelf. Relatively steep submarine profiles facilitate the mingling of deep-water and shallow-water groups, and individual species tend to have a wide bathymetric range. An echinoid, Pseudechinus flemingi sp. nov., is recorded from both living and Pleistocene examples.

A series of RV PROSPECTOR cruises to survey ferromanganese nodule deposits at depths of 4000- 5200 meters in the Clarion-Clipperton Fracture Zone of the north-eastern equatorial Pacific Ocean resulted in the acquisition of over 70,000 seafloor images. Real-time television, coupled with 35-mm remote-controlled still photography, revealed a conspicuous epibenthic invertebrate megafauna of more than 70 species. Approximately 38 species are echinoderms. Porifera and Cnidaria are each represented by approximately 12 species. Several molluscs and arthropods, a bryozoan, a hemichordate, and an ascidian urochordate constitute the remainder.

Although there has been increasing international commercial interest in developing the economic potential of the region, knowledge of the faunal elements present remains very limited. Many of the non-echinoderm megafauna from this increasingly important area are illustrated here in seafloor photographs. Several taxa are new to science; others represent new locality records or depth range extensions. Comments are given on systematic status, geographic and bathymetric distribution, and living habits of selected species.

A long term, large scale, disturbance-recolonization experiment with relevance tthe environmental effects of deep-sea mining is described. The study is funded by the West German government and was launched in the abyssal eastern tropical South Pacific Ocean in February- March, 1989 After obtaining pre-impact baseline environmental data, a 10.8 km2 circular area of seafloor was disturbed using a specially designed "plow-harrow" device. An initial post-impact sampling series was carried out immediately after disturbance and the site was revisited in September, 1989, for renewed post-impact sampling six months agter the disturbance. Plans call for repeated visits to the site at two year intervals in order to monitor the anticipated slow recolonization process until the area is inhabited by a new, stabilized community.

Metalliferous mineral deposits on the deep seabed are classified on the basis of form, sedimentary facies, and geological setting. All of the main types of deposits are genetically part of hydrothermal systems and include manganese nodules and crusts, metalliferous sediments and stratafer rocks, and hydrothermal vent deposits consisting of chimneys, stacks, talus, debris, mounds, and crusts. The distribution of deposits and their relation to prominent tectonic features in different parts of a spreading ridge system are illustrated in composite diagrams. Trends and patterns evident from empirical data are outlined for the location of sulfide, silicate, and oxide facies of metalliferous sediments in relation to hydrothermal effusive centres. The distribution of mineral occurrences in tectonic segments of the Juan de Fuca Ridge system is discussed briefly.

Seabed mineral deposits are composed mainly of manganese and iron oxide and sulphide minerals, and are classified as: manganese nodules and crusts; metalliferous sediments, including basal and surface facies, crusts, mounds, chimneys, and stacks at hydrothermal sites; and veins, stock works, and replacement masses in bedrock. A world map, scale 1.40 million, shows mineral distribution in relation to major tectonic features, continental margins and areas 370 km from shore. Geological settings are described for about 250 mineral occurrences in the Atlantic, Pacific and Indian oceans, for manganese nodules, and for cobalt-rich manganese crusts. Exploration along the axes ofspreading ridges has in general been selective and nonsystematic.

Manganese nodules containing 1.7 to 3.5% combined copper and nickel, in minimum abundance of 10 kg/m2, and with high manganese-iron ratios, occur in the north equatorial and south- west Pacific, Atlantic and Indian oceans, where there is minimal detrital sedimentation, high biological productivity, and where hydrothermal fluids were likely sources of metals. Manganese crusts containing 0.3 to 1% cobalt are common at depths of 800 to 2500 m on seamounts in the Central Pacific.

Metalliferous sediments are deposited by hydrothermal effusive systems that develop in the oceanic lithosphere where deep fracture zones coincide with anomalously high thermal gradients. Sulphide facies containing significant amounts of copper, zinc, lead, silver and gold are usually deposited near high temperature (50 to 4000 degrees C) hydrothermal vents, and commonly extend to siliceous oxide facies that are distal from vent sites and rich in iron, manganese, and nontronite clay or smectite. Many metalliferous facies on the seabed are similar in composition to iron-formations and related stratafer sediments mined on land.

Canada, with one of the largest continental shelf areas in the world, has done little to evaluate its offshore unconsolidated mineral resources which include heavy minerals (gold, chromite, rutile etc.) and industrial minerals (silica sand and aggregates). During glaciation much of the continental shelf was covered with an ice sheet and later subaerially exposed with the result that glacial, glaciomarine and fluvial processes deposited sediments that may contain heavy minerals derived from onland locations. With rising sea-levels, beach and nearshore processes may have served to concentrate heavy minerals by winnowing and removing the lighter mineral components. These potentially valuable resources can be found with suitable exploration techniques such as seismic profiling and bottom sampling. Gold deposits are known to exist off the coast of Nova Scotia, and on the basis of former beach mining, gold deposits probably occur off Vancouver Island and the Queen Charlotte Islands. Large deposits of silica sand occur near the Madeleine Islands and it appears likely that supplies of marine aggregates are present close to urban markets or sites of future mega-projects such as oil field developments. This paper, which is based upon a review of literature and consultation with members of the Department of Energy, Mines and Resources' Coordinating Committee on Ocean Mining (DCOM), is the first step in assessing the Canadian offshore for its resource potential with respect to quantltied deposits, known and speculative mineral occurrences. Although this is a subjective evaluation, the potential appears promising. A more detailed resource inventory is required to provide a more certain assessment.

Information on the fate, persistence and biological impact of petroleum hydrocarbons in shallow marine environments, coupled with recent data on hydrocarbons in offshore sediments and the biology of deep sea organisms, have provided new perspectives on the potential impact of oil on the deep sea environment. A review of literature on petroleum hydrocarbons in deep sea sediments, mechanisms for transport of petroleum to the deep sea floor, interaction of petroleum hydrocarbons and particulate matter, and the physiology and metabolism of deep sea fish and crustaceans has resulted in the following conclusions:

1. Hydrocarbons of apparent anthropogenic origin are accumulating in bottom sediments of coastal margins and in deeper offshore waters at unknown rates.
2. Several mechanisms exist for the rapid transport of petroleum hydrocarbons to the deep sea floor.
3. Petroleum hydrocarbons are intimately associated with particulate matter in the sea, behaving much the same as natural biogenic material and having the potential to modify or interrupt natural processes.
4. The unique physiology of deep water life forms increases the potential for adverse impact of petroleum hydrocarbons on the deep sea environment.
5. There is a need to determine trends of temporal and spatial deposition of hydrocarbons in deep sea sediments and evaluate the biological impact of this introduction of xenobiotic compounds on the largest environment on earth.

A preliminary investigation into the occurrence of manganese nodules and crusts south-east of Tarawa, western Kiribati, has shown that manganese nodules occur at five of the eleven localities sampled at abyssal depths. Nodules are of small size, the largest being 31mm in diameter. At only 2 stations were nodule densities greater than 1% (5% and 15% coverage) indicating a patchy distribution. Metal contents are also variable and at only one station do Co+Cu+Ni values (1.58%) exceed 1.5%, a value common elsewhere in the Central Pacific Basin. Richer and denser deposits may lie to the east of the area studies, on the abyssal plain north of the Phoenix Islands.

Environmental impact assessment for the extraction of metalliferous sulfides at ocean spreading centers represents a new and specialized area of environmental consideration. Previous work on deep-sea mining for manganese nodules and on Outer Continental Shelf activities provides a solid background, but is applicable only in principle. Metalliferous sulfides may be enriched in a wide array of elements about which very little biogeochemistry is known. Our knowledge of benthic ecology in the deep-sea is still sketchy, and this is especially true for the hydrothermal vent fauna, which were first discovered only eight years ago.

The Gorda Ridge represents the only ocean spreading center, and thus, the sole source of active mineralization of this type within the United States Exclusive Economic Zone. A scheduled lease sale for the Gorda Ridge was postponed in 1984, and led tthe formation of the joint federal-state Gorda Ridge Technical Task Force. The group is charged with an analysis of the economic, engineering and environmental implications of the proposed lease for metalliferous sulfides. The Task Force has recommended priorities for study, and exploration-oriented studies have begun, but environmental impact analysis will not occur for quite some time in the future.

Summary of Environmental Impact Statement

The environmental impact statement (EIS) discusses a proposal to lease PMS in the Gorda Ridge area offshore of Oregon and northern California and considers alternatives to the proposal. Issues raised during the scoping process and issues raised through staff analysis have been addressed in the EIS. In-place mitigation measures in the form of existing Federal, State, and local laws are considered in the impact analysis and additional potential mitigation measures that could be selected by the Secretary of the Interior are discussed.

The probable impacts discussion addresses exploration for PMS minerals, mining, transportation to coastal bases of operation, beneficiation of the PMS ore, and transhipment to smelters or refineries. To evaluate the impacts of the proposal, a number of assumptions have been made as to the type of mining operation that would occur in the lease area, transportation systems used, and onshore support and processing sites. In many instances, these assumptions represent a worst case picture of possible activities that might occur under this proposal. The following assumptions have been used in assessing probable impacts as a result of the proposal:

• Resource Evaluation—No quantitative assessment of resources is made other than sufficient resources are presumed to exist to support the most likely case and full development case scenarios.
• Most Likely Case Scenario—Three mining operations.
• Full Development Case Scenario—Five mining operations.
• Mining Method—Second generation mining of buried, massive PMS ore deposits involving: 1) removal of soft sediment or rock overburden, 2) open-pit mining operation, 3) explosives used to fracture rock, and 4) equipment similar to onshore surface mining but adapted to the deep ocean environment.
• Lifting to Surface—A slurry of seawater and crushed ore would travel to the surface in a pipeline with airlift assist.
• Surface Operations—A dynamically positioned platform and/or large ship(s) would power and control subsea operations. No ore processing at sea except to remove slurry water, water from the slurry discharged at the surface.
• Transportation to Shore—Barges and tugboats or self-propelled ore carriers would make several roundtrips from mine site to port each week.
• Onshore Support Bases—Coastal ports in Oregon and northern California large enough to accommodate vessels and closest to a lease area.
• Onshore Processing Sites—Located within a 3- to 4- day cruise of the lease area and large enough to accommodate deep-draft vessels (open space available) and apparent willingness to accomodate mineral processing activities. Possible sites have been defined in the coastal area from Grays Harbor, Washington, to the San Francisco Bay area, California.
• PMS Minerals Processing—Beneficiation of PMS ore to create metal concentrates for sale as feed stocks to existing smelters/refineries. No new construction of smelter or refinery capacity in the Pacific northwest is assumed.
• Onshore Transportation of Ore—Use of existing rail network with appropriate upgrading.
• Regulatory Framework—Three distinct phases of operations.
  1. An exploration phase to locate mineral targets.
  2. A development phase to delineate PMS ore bodies and to test equipment and mining methods.
  3. A mining/production phase of active PMS mineral extraction. Approved plans of operation required before beginning any phase of work on the lease.
• EIS Study Area—The Gorda Ridge lease area and adjacent coastal areas between Grays Harbor and San Francisco Bay.
• National Environmental Policy Act (NEPA) Compliance—All activities proposed on a ease will be reviewed in accordance with NEPA. Environmental analysis documents will tier on this EIS.

Probable Impacts as a Result of the Proposed Action (Preferred Action)

Thefollowing discussion of impacts considers the most likely case number of operations (3) and assumes that all existing laws and regulations are part of the proposal. Impact analysis does not assume that other mitigation that might be included in the terms and conditions of the proposed offering are in place. If proposed mitigation measures described in Section ll.A.l.c were adopted, it is expected that some impacts described in this EIS would be reduced. The potential effects of proposed mitigation measures are described in each impact section (Section IV.B). Definitions for impact levels are contained in Section IV.B.5.

Physical Environment—Impacts on surface water quality are expected to be very low to very high depending upon distance from the discharge point of water containing sediments and heavy metals. Rapid dispersion and dilution of pollutants would keep most adverse impacts localized and short-term. Benthic turbidity would have very high impact levels around the mine site but would diminish downcurrent due to settling and dispersion of sediment particles. Overall water quality impacts in the lease area would be low.

Modeling of air pollutant emissions from offshore operations indicates that very low air quality impacts would result onshore. Emissions from onshore operations sources such as equipment, boats, and fugitive dust would also be very low. Some odor from onshore processing might be detectable over short distances downwind. Wherever the ore is refined/smelted the existing air quality impacts associated with the refinery/smelter would continue.

Two low-level radioactive waste material dumpsites exist in the lease area. Radiation at each dumpsite at the time of disposal was 0.08 curies. Rupture of the radioactive waste containers, though unlikely, would release small quantities of radiation and have low level impacts.

Biological Environment—Degradation of surface water quality associated with increased turbidity and heavy metals would have some lethal and sublethal effects on phytoplankton. Reductions in primary productivity would be short-term and localized around and downcurrent of the water discharge point. Overall impacts on productivity would be low. Uptake of heavy metals by primary producers poses potential long-term impacts from bioaccumulation of metals in primary, secondary, and top consumers. These impacts would be experienced by a few individual fish feeding on contaminated prey. No lethal effects are expected but sub-lethal effects are possible. Impacts on fishery resources would be low to moderate with some insignificant loss of some commercial species.

Albacore pass through and are fished far in the lease area but should be able to avoid most areas of direct impact. Salmonids, which range throughout the northwest Pacific, might experience some sub-lethal impacts in a few individuals.

Impacts on benthic animals would be moderate to major. Large areas downcurrent of the mining site could be covered by sediments. Unique biological communities associated with hydrothermal vents near seafloor spreading centers could be affected by mining operations. Vent communities downcurrent from or near the mine site could experience major impacts.

Marine mammals and endangered species would be affected by vessel traffic and possibly by the use of explosives. Although some mortality to marine mammals and endangered species might result from vessel collisions, the impact level on populations of marine mammals and endangered species would be low. Vessel collisions could affect marine birds and onshore development could affect coastal birds. Impacts on bird populations would be low to moderate.

Estuaries around port areas that serve as bases of operations during mining could be affected by repeated, small spills of fuel and PMS ore materials. Heavy metal impacts on estuarine ecosystems include impacts on birds, anadromous fish, resident fish, and shellfish. Shellfish in particular tend to accumulate metals and the proposal could result in the contamination and closure of some shellfish beds, but estuarine impacts would be low to moderate. Coastal Areas of Special Concern in Califoria and existing (or proposed) marine sanctuaries would be largely unaffected by the proposal unless an accidental grounding of a fuel-laden or ore-laden barge happened in these areas. Impacts of an accidental grounding, though unlikely, could be moderate to high.

Socioeconomic Environment—Economic impacts on local communities range from high to low levels depending upon the size of the host community. Local employment and demographic changes induced by the proposal also have high to low impact levels depending upon the size of the host community. Competition for open land and docking space, construction of new facilities, and increases in PMS-related vessel traffic all generate impacts easily absorbed in a large port area such as San Francisco Bay but create major impacts on smaller ports like Coos Bay and Astoria, Oregon. Upgrades of the existing transportation infrastructure would be necessary in each port area considered in the EIS.

The commercial fishing industry would be largely unaffected by the proposed action. Impacts on fishing and fishing support industries due to any loss of fishery resources would be very low to low. Native Americans and unemployed persons in the coastal area who have a subsistence lifestyle would experience low level impacts, to the extent that they rely on fishing.

Impacts on recreation, aesthetics, and tourism would occur near onshore bases. Construction of new facilities and routine operations would have very low level impacts. The lease area is too far offshore for visual impacts in the coastal area.

Shipwrecks on the lease area are the only cultural resource that might be affected at sea. Onshore construction could also affect cultural resources; however, impacts on cultural resources would be low.

Impacts on military activities are uncertain at this time. The Minerals Management Service is discussing possible joint use conflicts of the Gorda Ridge lease area with the U.S. Navy. At this time, impacts on military activities could range from very low to high depending upon the results of ongoing discussions.

Probable Impacts of Alternatives II through VIII

Alternatives II through V of the lease offering would alter the size and configuration of the tracts offered for lease. Alternative II would offer the entire Gorda Ridge lease area in 40 tracts of 4,000 to 5,000 km2 area each. Alternative Ill would offer half of the lease area, 90,000 km2, in five tracts of the same size and configuration as the proposed action (Alternative 1) but would delete every other tract. Alternative IV would offer half of the lease area, 90,000 km2, in 20 tracts of the same size and configuration as in Alternative II but would delete every other tract to create a checkerboard pattern. Alternative V would offer the entire Gorda Ridge lease area as a single tract.

The purpose of Alternatives II through V is to provide the Secretary of the Interior with options on the size and configuration of the lease offering. Alternatives III and IV, the alternate tract deletion options, would allow the Department of the Interior to retain control over half of the Gorda Ridge lease area. The retained portion could be offered at a later time to augment existing PMS mineral production or offered when more information on potential resources is available.

All mining methods and production assumptions made under the proposal are the same for Alternatives II through V. As a result, the probable impacts for these alternatives are assumed to be the same as for the proposed action, Alternative I.

Alternative VI would delete from the proposal all areas of the continental slope shallower than the 2,500-meter isobath. This alternative could be used in conjunction with Alternatives I through V. The purpose of this alternative is to reduce potential conflicts between PMS mineral operations and commercial fishery activities over the continental slope. Impacts on fisheries has been identified as a key concern during the scoping process. This would serve to alleviate part of the concern over this issue. An additional benefit would be to remove one of the radioactive waste disposal dumpsites from the lease area. The effect of this deletion would be to reduce impacts to commercial fishing and to reduce potential impacts from radioactive waste hazards.

Alternatives VII and VIII (No Action) would delay or cancel the proposed lease offering, respectively. Possible impacts from these alternatives would range from postponement of the impacts that would result from the proposed action to no impacts from PMS mineral activities. All existing activities and impacts in the lease area and onshore areas would continue with or without the proposal. If the delayed offering were rescheduled or the cancelled offering were reinstated, all impacts that were associated with the original proposal could occur. Impacts on domestic sources of minerals could result from either alternative and might affect the national economy, domestic minerals independence, and national security and defense.

Delaying the offering or developing a new proposal at a later date could allow additional information to be obtained on PMS mineral resources and environmental resources. Advances in technology or improvement in metals markets might occur during this time. Incorporation of new information in the existing proposal or a new proposal might create better mineral development programs and safer operations with less environmental risk.

This report summarizes the latest research on the effects of beach nourishment and borrowing on the coastal environment. Guidelines are formulated for sampling the beach and nearshore, and recommendations for minimizing the impact of beach nourishment and borrowing are provided.

The National Oceanic and Atmospheric Administration (NOAA) has prepared this environmental impact statement (EIS) pursuant to Section 109(d) of the Deep Seabed Hard Mineral Resources Act ("the Act"), NOAA regulations implementing the Act (15 CFR Part 970, Deep Seabed Mining Regulations for Exploration Licenses) and Section 102(2)(c) of the National Environmental Policy Act of 1969 (NEPA). The Act authorizes the Administrator to issue licenses for exploration and permits for commercial recovery of manganese nodules in the deep seabed, subject to appropriate terms, conditions, and restrictions (TCRs).

Under Section 4(5) of the Act, exploration means:

1. any at-sea observation and evaluation activity which has, as its objective, the establishment and documentation of:
   • the nature, shape, concentration, location, and tenor of a hard mineral resource; and
   • the environmental, technical, and other appropriate factors which must be taken into account to achieve commercial recovery; and
2. the taking from the deep seabed of such quantities of any hard mineral resource as are necessary for the design, fabrication, and testing of equipment which is intended to be used in the commercial recovery and processing of such resource;

NOAA proposes to issue an exploration license subject to TCRs (15 CFR 970.500) for a period of ten years to carry out exploration activities as set forth in an application for a deep seabed mining license submitted to NOAA by Ocean Minerals Company (OMCO). This EIS assesses the potential environmental impacts of issuing an exploration license to OMCO and of alternatives to issuance of the exploration license.

The license activities will take place in the area between the Clarion - Clipperton fracture zone in the Northeast Equatorial Pacific Ocean, between Central America and Hawaii. These activities would assist OMCO in delineating its exploration area for manganese nodules, which are fist-sized concretions of manganese and iron minerals that occur on the sea bottom in areas of low sediment deposition around the world. Manganese nodules are rich in four strategic metals — nickel, cobalt, manganese, and copper. Nickel, currently supplied to the United States chiefly from land-based mines in Canada and New Caledonia, is used for high-temperature alloys used in aircraft. Cobalt, imported mainly from Zaire, is used in the electrical industry for permanent magnets. Manganese, which is supplied to the United States by Brazil, Gabon, South Africa (expected to be our major source in the future), and Australia, is essential to the production of steel. Copper, in which the United States is nearly self-sufficient, is used mainly in electrical equipment. If commercially feasible, nodule mining can provide an increasingly important domestic source for these strategic metals as foreign producers retain more of their domestic output (and therefore export less) in the years ahead.

OMCO submitted two applications for exploration licenses pursuant to NOAA regulations in early 1982, which are now consolidated into one application. These areas applied for were in conflict with other deep seabed applications filed with NOAA. By January 1984, OMCO and three other applicants filed amendments that resolved these conflicts; OMCO set forth approximately 165,000 km2 included in its amended submission.

This EIS summarizes the findings of NOAA's programmatic environmental impact statement (PEIS) of September 1981, then assesses issues related to issuing the OMCO license. OMCO's proposed activities as set forth in its exploration plan are designed to delineate further the extent and distribution of nodules, the topography of the seafloor, including obstacles, and properties of seafloor sediments in order to establish an area for ommercial recovery from the larger exploration area. Specifically, OMCO proposes to use acoustic data, photography, satellite navigation, and samples by means of grab samplers, dredge baskets, box cores, gravity corers, and free fall corers to delinate its exploration area. The worst case potential for impact involves sampling with dredge baskets and the resultant loss of 54 kg of benthic biomass, about one millionth of that in OMCO's license area. Sampling impacts could also be caused by the other two U.S. applicants contemplating this type of sampling and by the French and Japanese consortia should they sample in this manner. Japan has announced its intention to test a hydraulic mining system around 1990. Although these activities appear to have no potential for significant environmental impact and would not normally require preparation of an EIS, Section 109(d) of the Act nonetheless requires that NOAA prepare this EIS to assess the impacts of issuing any license.

NOAA's environmentally preferred alternative is to issue, rather than delay or deny issuing, the exploration license to provide better understanding of environmental impacts of deep seabed mining and to reduce the reliance on and impacts of land based mining. This conclusion is consistent with the purposes of the Act and reduced dependence on foreign sources of strategic metals.

No endangered species are expected to be affected by OMCO's proposed activities. Based on consultation with other Federal agencies and the opportunity for public review and comment, NOAA's proposed TCRs provide for OMCO:

1. to report any endangered species that it observes;
2. to report and protect cultural resources, such as shipwrecks, that it discovers in the license area; and
3. provide a monitoring plan and environmental baseline information in accordance with NOAA Technical Guidance Document (TGD) at least one year in advance of any proposed equipment test, so that a supplement to this EIS can be prepared on the proposed activities.

The Environmental Protecion Agency (EPA) is developing a general National Pollutant Discharge Elimination System (NPDES) permit for all vessels operating under NOAA exploration licenses.

No onshore processing activities are proposed in OMCO's application.

Based on the foregoing analysis and information, NOAA has tentatively determined that the exploration proposed in OMCO's application cannot reasonably be expected to result in a significant adverse effect on the quality of the environment (15 CFR 970.506). This determination is necessary before NOAA may issue a license for deep seabed mining exploration activities.

This EIS also summarizes NOAA's environmental research since 1981 concerning unresolved issues in the PEIS.

The National Oceanic and Atmospheric Administration (NOAA) activities related to the implementation of the Deep Seabed Hard Mineral Resources Act (P.L. 96-283, the Act) in fiscal years 1984 and 1985 are described in this third report to the Congress. The effort has included the completion of the processing of applications from four U.S. based, muitinational mining consortia for NOAA licenses for exploration. Licenses were issued in 1984 and all four consortia are now authorized to conduct exploration activities in their respective areas for the 10 year duration of the licenses.

Activities conducted by the licensees during the first year of the license consisted primarily of completing the exchange of exploration data with other consortia as a result of the private agreements resolving site conflicts. The evaluation, analysis, and integration of these data into their existing data bases has begun.

NOAA also has been proceeding with the development of proposed commercial recovery regulations. The proposed regulations should be published for public comment in 1986.

Research is continuing into the environmental, economic, and mineral resources aspects of deep seabed mining.

NOAA and the Department of State concluded discussions with other seabed mining nations on an agreement to avoid seabed mining conflicts. A "Provisional Understanding Regarding Deep Seabed Matters" was signed and the NOAA Administrator has designated four nations (the Federal Republic of Germany, France, Japan, and the United Kingdom) as reciprocating states. NOAA is continuing to consult with other mining nations to establish a network for exchange of information on environmental research efforts and regulatory measures to protect the environment.

This PEIS is prepared pursuant to the Deep Seabed Hard Mineral Resources Act (P.L. 96-283, "The Act") and the National Environmental Policy Act of 1969 (NEPA) to assess the impacts of deep seabed mining for manganese nodules. Exploration by United States citizens will be authorized by license from the National Oceanic and Atmospheric Administration (NOAA) beginning in the next few years, followed by commercial mining under NOAA permit no earlier than 1988 and continuing indefinitely. The area of interest is the Pacific Ocean (about 4,500 m or 15,000 ft deep) in a 13 million km2 (3.8 million nmi2) area of the equdtorial high seas, roughly between Central America and Hawaii. The PEIS includes the marine and onshore impacts of the mining of nodules from the deep seabed, their transport to onshore, onshore processing, and waste disposal. Four strategic metals (nickel, cobalt, manganese, and copper) will be produced by this new U.S. industry. Mining in other ocean areas, at-sea processing, and mining with techniques other than hydraulic methods are not discussed in depth in this PEIS.

Deep seabed mining will occur in ocean areas beyond the jurisdiction of any nation. Therefore, mining probably will be conducted in cooperation with other nations licensing deep seabed miners through a system of reciprocal state agreements. Authorization may also be granted by an International Seabed Authority should a Law of Sea treaty enter into force for the United States.

Marine impacts occur in the water-column and on the seafloor. In the water column, the major effect with potential for significant adverse impact involves effects on fish larvae. On the seafloor, organisms will be lost during the collection of nodules from the ocean floor. Neither of these impacts is expected to be significant during the exploration phase. The PEIS discusses regulated mining under the Act as NOAA's preferred alternative, with continuing review of environmental impacts through monitoring and environmental research. It also discusses examples of mitigation measures and approaches to conservation of resources likely to arise through commercial recovery.

NOAA will serve as lead agency for environmental review of onshore processing and facilitate other government approvals to the extent practicable and desirable.

The world's most valuable known supply of manganese nodules lies three miles deep in international waters of the Pacific Ocean between Central America and Hawaii. Rich in strategic metals, these fist-sized nodules are being explored and analyzed by five international industrial consortia, four of which include U.S. companies. The metals — copper, nickel, cobalt, and manganese — are essential for the production of steel, aircraft engines, alloys, and other industrial materials. The United States currently imports large quantities of these metals, including virtually all of its cobalt and manganese. Zambia and Zaire provide most of the world's cobalt. By the end of the century, the Soviet Union and South Africa are expected to control virtually all the world's manganese resources. An independent, secure supply of these resources would preclude interruptions of supply or monopoly price increases.

Current international law provides no specific system for guaranteed access to a site. Such guarantees are necessary to protect the more than one-billion-dollar investment ultimately needed to undertake deep seabed mining. Although an international Law of the Sea treaty presently is in the process of negotiation, the current regime for deep seabed mining is based on national law, which provides for deep seabed mining as a freedom of the high seas.

In June 1980, Congress enacted the Deep Seabed Hard Mineral Resources Act (P.L. 96-283), to provide an interim legal framework, pending an acceptable treaty, to faciIitate the continued development of deep seabed mining in an orderly and environmentally sensitive manner. The authority for implementing the Act, and for issuing to U.S. citizens licenses for exploration and permits for commercial recovery, was given to the National Oceanic and Atmospheric Administration (NOAA). Within NOAA, authrity was assigned to the new Office of Ocean Minerals and Energy (OME). From the enactment of the law, NOAA proceeded to carry out its responsibiIities by assembling and using people and funds from the agency's Marine Minerals Division, other elements of NOAA, and other federal agencies. During this period, the framework for the program was put together.

In pursuing its efforts, OME held a series of public meetings to produce regulations to implement Titles I and II of the Act and to develop environmental information. In March 1981, NOAA issued a Notice of Proposed Rulemaking and a draft programmatic environmental impact statement, as required by the Act. In September, the final regulations (Deep Seabed Mining Regulations for Exploration Licenses, 15 CFR Part 970, at 46 CFR 45890) and a supporting final programmatic environmental impact statement were published on schedule and as required by the Act. At the same time, NOAA issued a technical guidance document to assist license applicants. The regulations established the legal framework for deep seabed mining exploration by U.S. industry.

Aside from a few environmental and exploratory surveys by "grandfather" pioneer companies no exploration or commercial recovery has been undertaken during the period covered by this report, and consequently there have been no adverse environmental impacts. No legal proceedings have been undertaken and no license or pemit applications have been received. NOAA anticipates receiving license applications in early 1982.

The Act also provides for negotiation of mutual recognition of Iicenses with other nations that have authority to license deep seabed mining, and for NOAA to designate such nations as reciprocating states. To this end, NOAA and the Department of State engaged in negotiations with these nations. The Federal Republic of Germany, United Kingdom and France have enacted such legislation. At the same time, NOAA began negotiations on establishing stable reference areas, to be used as a baseline zone for evluation and enviromental assessment, as required by the Act.

In addition, NOAA submitted a report to Congress, on June 24, 1981, dealing with protection of interim investments, pursuant to section 203 of the Act. The agency also prepared a five-year ocean research plan to support environmental assessment studies, as required by the Act. Although the report was reviewed in draft form by appropriate Congressional committees, its formal submission report to Congress was deferred, with the agreement of the committees, pending the Admininstration's review of NOAA's budget.

The programmatic environmental impact statement concluded that some impacts occur in the water column and on the sea floor. In the water column, the impact during commercial recovery may be significant on fish larvae. On the seafloor, organisms will be lost during the actual collection of nodules. However, these impacts are not expected to be significant during the exploration phase. Environmental impacts will be monitored and evaluated during system tests of nodule collection equipment and during commercial recovery. Meanwhile, NOAA will continue to examine potential environmental impacts and their significance.

On shore, environmental impacts can occur in ports and at transfer facilities, as well as during processing and disposal of wastes. While existing controls are generally adequate to protect against adverse impacts, NOAA, in cooperation with other agencies, will examine disposal of wastes to determine whether tailings require special attention. NOAA will serve as the lead agency for environmental review and faciIitate other state and federal permits.

NOAA also worked with the Environmental Protection Agency (EPA) to secure a general National Pollutant Discharge Elimination System permit. EPA intends to issue a general permit for exploration, and has already started working toward that end.

OME has begun pre-application consultations with industry, to ensure prompt processing of license applications and to support site-secific environmental impact statements. NOAA anticipates early designation of initial reciprocating states. With respect to the commercial recovery phase of seabed mining, NOAA has already begun to work on the framework for regulations in anticipation of commercial recovery, which cannot start under the Act until 1988.

In addition to work under the Act, NOAA will assess other ocean minerals, including the polymetalIic sulfide ores recently found at spreading centers between the plates on which the world's continents set. Such valuable metals as copper, zinc, and silver were discovered on the edges of these tectonic plates. NOAA will evaluate their potential and consider environmental research and legal regimes that would have to be established before commercial recovery could take place.

NOAA has reviewed the Act and implementing regulations, and concluded that the deep seabed mining program can be implemented at least until the next biennial report to Congress without modification of the Deep Seabed Hard Mineral Resources Act.

The results of environmental studies conducted during the monitoring of a pilot-scale manganese nodule mining operation by Deepsea Ventures, Inc./Ocean Mining Associates are presented. These studies included observations of the chemical and physical structure of the upper 300 m of the water column, nephelometry and particulate sampling, light profiles, primary production experiments, and macrozooplankton studies. These observations were made prior to mining operations in the ambient water and during the 18 hours of mining.

The characteristics of the mining discharge were found to be: flow rate 80-95 P/s; total particulate concentration 3-9 g/P; temperature 4-5 degrees C; bulk density l.029-l.032 g/cm3; Fe 6% by weight; Mn 2.76% by weight; and Ca 0.93% by weight.

The plume generated by the mining discharge was visible 2 km from the mining ship, with a width of 300-400 m at that distance. However, the plume was detectable by nephelometry at a distance of 7-8 km, which corresponds to a plume age of about 12 hours. Nephelometer records indicate that the near-surface concentration of particulates in the plume decreased from 900 mg/P, at a distance of 70 m from the mining ship, to about 70 mg/P at 8 km. Background particulate concentrations in the area were 30 mg/P. The plume was observed to be confined to the upper 40 m in three casts made at plume ages of one, two, and three hours.

In one-hour-old plume water, the total light attenuation coefficient in the upper 25 m layer increased fourfold to 0.14/m from the mean ambient value of 0.034/m due to shading by the particulates. Based on this reduction in light intensity and on ambient in situ and on-deck primary production measurements, a reduction of about 40% in primary production long the plume axis is estimated in a one-hour-old plume. This is a very limited area, and overall reduction in primary production within the total plume would be much less.

The mining discharge did not have any other effect on primary production according to on-board experiments lasting less than one day. Similarly, the results of field observations and experiments conducted for periods of one to two days suggest that mining discharge has no significant effect on macrozooplankton at the concentration levels observed during this pilot mining test.

Substantive Canadian interest in offshore non-fuel mineral development began with deep seabed manganese nodules duing the 1970's and now includes shelf mineral deposits and seabed polymetallic sulphides.

While a number of Canadian companies conducted background studies and took part in small-scale ocean mining tests, only two, Inco Ltd. and Noranda Mines Ltd., made a major commitment to the research and development efforts of the ocean mining consortia during the 1970's. At the same time, the Canadian government was actively evaluating deep seabed development potential in relation to its positions at the ongoing negotiations at the United Nations Law of the Sea Conference. Both industry and government efforts have tapered off in recent years, although as a signatory to the Treaty, Canada participates in the Preparatory Commission in an effort to develop a workable seabed mining regime and a universally accepted Law of the Sea Treaty.

In the early 1980's entrepreneurial interest and resource assessment work indicated that the Canadian offshore is a potential source of materials such as aggregates, silica sand, and placer gold. The Department of Energy, Mines and Resources is now working cooperatively with the provinces and industry to enhance awareness of Canada's offshore mineral potential and to address structural problems that are inhibiting offshore development.

Canadian university and government scientists are studying the types and distribution of polymetallic sulphide deposits and related metalliferous sediments found off Canada's west coast. While the medium term benefits are likely to be better exploration guidelines for locating ancient onland deposits, the information will also be used to evaluate the longer term development potential of these seabed deposits.

A compilation of over 100 mineral occurences at oceanic ridges and rifts comprising the global seafloor spreading center system has been made in terms of host-rock lithology (volcanic- or sediment-hosted) and of stage (early, advanced) and rate (slow-, intermediate- to fast- spreading) of opening of an ocean basin. At this early phase of exploration when less than 1 percent of the ~55,000 km global length of spreading Centers has been systematically explored, examples of almost all major varieties of volcanic- and sediment-hosted hydrothermal deposits associated with basaltic rocks in the geologic record have been found at present spreading centers. Review of this global data base indicate that a range of hydrothermal mineral-deposit sizes from small to large greater-than-or-equal-to 1x 106 tonnes) occurs at all seafloor spreading rates. Based on available data, however, larger deposits (but fewer per unit length of spreading axis) form at slow- rather than at intermediate- to fast-spreading centers. Larger deposits are more common in sediment- hosted than in volcanic-hosted settings regardless of spreading rate. A spectrum of hydrothermal deposit varieties (stratiform, stockwork and disseminated sulfides; various forms of sulfate, carbonate, silicate, oxide and hydroxide deposits) occurs in almost all of the tectonic settings. High- intensity, ore-forming, subseafloor, hydrothermal convection systems that conserve heat and mass, and concentrate hydrothermal precipitates, are extremely localized by anomalous physical and chemical conditions relative to nearly ubiquitous low-intensity hydrothermal activity at, and flanking, seafloor spreading axes at all spreading rates. Two distinct shapes of volcanic-hosted hydrothermal deposits at seafloor spreading centers and in the geologic record may be explained by differences in fluid dynamic behavior controlled by temperature-salinity properties of solutions. Massive sulfide deposits tha are mound-shaped in profile are constructed by hydrothermal solutions that discharge as buoyant plumes; examples are the TAG massive sulfide mound forming on the Mid-Atlantic Ridge, and the Archean Noranda-area deposits. Massive sulfide deposits that are saucer- or bowl-shaped in profile are formed by ponded solutions denser than surrounding seawater; examples are the Atlantis II Deep deposits of the Red Sea, and the Cretaceous Troodos deposits of Cyprus. Review of an existing data set on 508 massive sulfide deposits in the geologic record indicates that fewer volcanic- and sediment-hosted massive sulfide deposits are associated with basaltic rocks than with rhyolitic rocks (< 26% versus 56%, respectively). This observation suggests that seafloor spreading centers have been significant as tectonic settings for massive sulfide formation through geologic time, although subsidiary to continental rifts and volcanic island arcs.

Life on continental slopes is characteristically zoned with depth. Faunal variation across the slope appears to occur more rapidly than anywhere else in the deep-ocean environment, but the causes of the narrow zonation are not known. A diversity of causes is possible, including competition for a diminishing resource (food), very efficient predation, pressure effects on enzymes, and also conditions such as extremely low dissolved oxygen or variations in the physical properties of the sediments. The composition of the fauna on continental slopes is not entirely unique, sharing species both with the continental shelf and continental rise, but nonetheless the slope can be considered a distinct biological province. The abundance of life and rates of physiological processes are intermediate between those of the shallow continental shelf and the abyss. Rates of change do not follow smooth gradients across the slope. At the base of the slope, where organic-rich sediments from shallow depths have accumulated, there is an important transition zone to the more truly oceanic conditions of the continental rise. Petroleum and phosphorite resources on the continental slope, using biological criteria, would most likely occur in regions historically characterized by upwelling, high productivity and low oxygen concentrations. Like the fauna itself, these resources should occur in zones. Because continental slope depths and beyond are important in the remineralization of organic matter, those involved in the exploration for and utilization of deep-sea resources must keep in mind that alteration of normal biological processes there might adversely affect the natural and vital biochemical cycling.

This report gives biological and physical oceanographic data from base-line work, and studies of dredged and underaged sediments before and after dredging (9-meter contour) for beach nourishment at Panama City Beach, Florida. These studies were designed to show major short-term environmental effects of offshore dredging and included analyses of hydrology, sediments, and benthos.

Hydrological measurements were limited to water temperature and salinity. Analysis of surface sediments included particle-size distribution, carbon chemistry, and statistical properties of mean grain size, sorting, skewness, and kurtosis. Average and extreme periods of water temperature and salinity were recorded. Regional nearshore sediments proved to be fine sand, containing less than 1 percent silt-clay, that was moderately well to well sorted, symmetrical to coarsely skewed, and leptokurtic. Total carbon content averaged less than 0.30 percent, and most of that occurred in the form of carbonate deposits. Over a postdredging study period of 1 year, sediment samples from borrow pits showed little variation from these general features.

In studies of the benthos, 362 species and 55,068 individuals were recorded among 14 invertebrate phyla and bony fishes. Dominant groups by species and abundance included annelida, mollusca, and arthropoda (crustacea). Faunal comparisons between dredged and underaged areas were made on the basis of species richness and abundance, the Shannon-Weaver index of diversity (H') Pielou's index of equitability (J'), Morisita's index of faunal similarity (together with matrices and classification diagrams derived from that index), and two statistical derivations, based on diversity and abundance data, that were designed to show sample-to-sample faunal variations and the time period required for faunal recovery in borrow pits. Information obtained from these procedures showed that recovery began soon after dredging and was complete, or nearly so, within 1 year.

These results were similar in most respects to those from study of offshore dredging elsewhere in comparable geographic settings. Even so, the need for close association between ecological research and coastal engineering programs is emphasized.

Laboratory-produced wastes (tailings) from five proposed commercial ferromanganese nodule processing schemes were leached for 1-day and 30-day periods in seawater. The seawater was analyzed for 11 elements using atomic absorption spectrophotometry after extraction at pH 3.90 with ammonium pyrrolidine dithiocarbarnate into methyl isobutyl ketone. A fraction of the seawater was not extracted, and analyzed directly. The concentrations of Mn, Ni, Tl, Fe, Cu, Co, Cd, and Zn were elevated in the leachates with respect to normal seawater, and numerous elemental concentrations changed significantly after a 30-day leach period when compared to the 1-day leach.

This report is in fulfillment of a legislative requirement for information on the progress made by the State Department in the establishment of international Stable Reference Areas (SRA) in ongoing negotiations on deep seabed mining.

The U.S. Department of State has discussed the concept of SRAs with other potential deep seabed mining countries. The talks have taken place under the general aegis of Section 118 of the Deep Seabed Hard Mineral Resources Act. However, up to this time, in-depth discussion of SRAs has been deferred pending completion of a thorough study of the scientific requirements for meaningful implementation of the SRA concept. This report highlights the steps that have been taken to define scientific needs. It also discusses the efforts that have been made on behalf of SRAs in the international setting.

An arthropod species was photographed several times in the Peru Basin at depths around 4150 m that could not be affiliated with one of the known deep-sea taxa. Hypothetically, it is placed in the Arachnida, near to the Amblypygi (order Pedipalpi).

The report concerns itself with the potential environmental effects of deep seabed mining. It primarily addresses mining for manganese nodules since relatively little information is available on the other deep-sea resources and their methods of exploitation. The current status of technological developments and their potential impacts on the environment are described. Special emphasis is given to future research needs and requirements. From these it is concluded that international cooperation is required not only from a scientific perspective, but also with respect to bearing the significant cost burden associated with deep-sea environmental protection. In the last chapter, recommendations are made as to what must be achieved for protection of the oceans. These include suggestions for changes or modifications to the Mining Code being developed by the Preparatory Commission for the United Nations Seabed Authority.

Mining the abyssal seafloor for manganese nodules will destroy the hard substrate and it will severely disturb the seabed and the benthic soft substrate community. Recolonization will occur from unmined areas. Reestablishment of a community similar to that originally present is, however, not possible, since the nodules will be removed and epigrowth on hard substrates is thereby precluded. Small scale experiments using azoic sediments in trays exposed to ambient deep-sea conditions, may not be appropriate models for large scale recolonization processes.

Results of such experiments and general knowledge of deep-sea ecology suggest that decades may be required for reestablishment of a balanced community.

With respect to evaluation of some ecological consequences of mining an ongoing large scale experiment, termed DISCOL (DIS-turbance and re-COL-onization) is shortly described as a new approach in deep-sea risk assessment.

In a midoceanic region of the northeast Atlantic, patches of freshly deposited phytodetritus were discovered on the sea floor at a 4500 m depth in July/August 1986. The color of phytodetritus was variable and was obviously related to the degree of degradation. Microscopic analyses showed the presence of planktonic organisms from the euphotic zone, e.g., cyanobacteria, small chlorophytes, diatoms, coccolithophorids, silicoflagellates, dinoflagellates, tintinnids, radiolarians, and foraminifers. Additionally, crustacean exuviae and a great number of small fecal pellets, "minipellets", were found. Although bacteria were abundant in phytodetritus, their number was not as high as in the sediment. Phytodetrital aggregates also contained a considerable number of benthic organisms such as nematodes and special assemblages of benthic foraminifers. Pigment analyses and the high content of particulate organic carbon indicated that the phytodetritus was relatively undegraded. Concentrations of proteins, carbohydrates, chloroplastic pigments, total adenylates, and bacteria were found to be significantly higher in sediment surface samples when phytodetritus was present than in equivalent samples collected at the same stations in early spring prior to phytodetritus deposition. Only the electron transport system activity showed no significant difference between the two sets of samples, which may be caused by physiological stress during sampling (decompression, warming). The chemical data of phytodetritus samples displayed a great variability indicative of the heterogeneous nature of the detrital material. The gut contents of various megafauna (holothurians, asteroids, sipunculids, and actiniarians) included phytodetritus showing that the detrital material is utilized as a food source by a wide range of benthic organisms. Our data suggest hat the detrital material is partly rapidly consumed and remineralized at the sediment sutface and partly, incorporated into the sediment. Incubations of phytodetritus under simulated in Situ conditions and determination of the biological oxygen demand under surface water conditions showed that part of its organic matter can be biologically utilized. Based on the measured standing stock of phytodetritus, it is estimated that 0.3-3% of spring primary production sedimented to the deep-sea floor. Modes of aggregate formation in the surface waters, their sedimentation, and distribution on the seabed are discussed.

Benthic fauna from two stations within a 5-year-old borrow area and two control stations off Hillsboro Beach (Broward County), Florida, were sampled quarterly from June 1977 to March 1978 to evaluate the long-term impact or offshore dredging. Generally enhanced productivities occurred within the borrow area, although there was much seasonal variation among stations. Species diversities were usually higher at the borrow stations than at the control stations. The single exception was due to a high concentration of the bivalve E.nitens at one of the control stations in June. Although faunal similarity analysis revealed a qualitative change in the fauna of the borrow area, this change is not considered detrimental. Conspicuous patterns of heterogeneous faunal distributions were evident in this study, particularly for the bivalve E. nitens. No lasting detrimental effects, in terms of numbers of species, faunal densities, or species diversity, resulted from the dredging operation.

Among the many products available for exploitation in the ocean are metalliferous muds. The mining of such products is relatively new and requires substantial research to determine environmental impacts. A pilot study of metalliferous mud mining in the Red Sea found that mud tailings may spread over a wide area and pollute sea water with potential ill effects for marine organisms. Nevertheless, the results were nonconclusive; an in-situ test will be necessary for an effective risk assessment.

The Tampa Harbor Project was a major dredging project for Tampa, Florida that widened and deepened the existing shipping channel. The Project began in 1975, and was completed in 1985. Approximately 53.5 million m³ of dredged material were removed from the existing channel; the majority of the material was placed adjacent to the channel. However, approximately6.4 million m³ were ocean-disposed. The Environmental Protection Agency and the Corps of Engineers were involved in all aspects of the project, and a number of local and State organizations were considerably involved in portions or the planning process.

This paper reviews all aspects of the Tampa Harbor Project, from the initial disposal operations at Site A, the litigation initiated by Manatee County, the subsequent trial and judicial outcome, the numerous surveys for an alternate disposal Site, the formulation of the monitoring and management plans, the selection of a new disposal area at Site 4, and the resumption of disposal operations. It also discusses the scientific data, results and conclusions of the monitoring operations, including the emergent biological growth on both Sites A and 4, following cessation of disposal operations.

Habitat distributions within 9,627,000 ac (3,896,047 ha or 15,042 mi²) of the Southwest Florida nearshore continental shelf were mapped. Within 5,006,000 ac (2,025,928 ha), habitat distributions were mapped from aerial imagery. In an additional 4,622,000 ac (1,870,523 ha), habitat distribution patterns were extrapolated from ground survey data. Four geomorphically distinct sub-areas exist within this study area:

1. the inner southwest Florida continental shelf, dominated by low-relief hard and soft coral communities and Halophila decipiens stands
2. Florida Bay, dominated by communities of Thalassia testudinum, Syringodium filiforme, and Halodule wrightii;
3. the Lower Florida Keys, dominated by Thalassia, Syrinpodium, and Halodule stands and patch reefs; and
4. the Tortugas/Marquesas Reef Banks, dominated by sand banks and coral reefs.

In terms of area, the deep-growing seagrass stands of H. decipiens were the most widely distributed habitat surveyed. These seagrass communities covered 3,004,000 ac (1,215,719 ha) of the inner southwest Florida continental shelf, or 31% of the entire mapped area.

No Halophila engelmannii was seen anywhere on the southwest Florida continental shelf during this study. The absence of this species is conspicuous since it has previously been reported from the Southwest Florida shelf, and was abundant on the northwest Florida continental shelf (Big Bend area) during studies conducted in 1984 and 1985. No explanation for its absence off Southwest Florida during the 1988 sampling period has been advanced.

Halophila decipiens appears seasonally on the west Florida shelf, beginning in late May and early June. These deep seagrass beds grow rapidly and reach a peak standing crop in late September. Following this biomass peak, new blade production drops off and beds begin to deteriorate. Rhizome structure weakens, and these beds are washed away with the onset of severe winter weather.

Halophila decipiens biomass peaked in the 70 to 90 ft (21.3 to 27.4 m) depth range. Deeper than 100 ft (30.5 m), H. decipiens began to be replaced by a long-bladed form of Caulerpa prolifera in suitable growth substrates. No H. decipiens was seen at depths >l22 ft (37.2 m).

Mean biomass of H. decipiens across the inner Southwest Florida continental shelf was 194.0 mg/m in September 1988. Extrapolation from this figure yielded a standing crop estimate of 2,600 tons (2,359 metric tons). The fate of this organic material within the continental shelf ecosystem is not well understood. Very little of it is eaten directly. Some of the disintegrated leaves appear to enter the detrital food chain, while others may be swept off the continental shelf to become a potential food source in deeper waters.

In April 1992, the Minerals Management Services Office of International Activities arid Marine Minerals initiated a field study to evaluate the extent of marine benthic organism repopulation in a dredged area. Through coordination with the U.S. Army Corps of Engineers, four dredge sites off the west coast of Florida, south of St. Petersburg, were selected for study. The study's instrumentation and sampling involved box coring, otter trawling, and using a towed sled carrying a video camera and a sidescan sonar device. The baseline collection phase of the study began in mid-July 1992, before the actual dredging of the sites. Subsequent postdredging cruises occurred over a period of 22 months. Preliminary evaluation of the data indicates that repopulation occurred very quickly and that, apart from some dredge holes that are still evident in some areas, there appears to be little overall impact from the dredging operations.

The DISCOL (Disturbance-recolonization) project started in l989 on the abyssal sea floor of the Peru Basin in the southeastern tropical Pacific Ocean with financial support from the German government. Conceived as a long-term, large-scale, in situ, experiment to assess some of the key environmental impacts expected to be associated with future deep seabed mining operations this pioneering effort has obtained results that are of interest from a basic as well as applied science perspective. Fundamental data have been and are continuing to be obtained on the rate, sequence, and direction of benthic community recolonization after severe anthropogenic disturbance.

Increasing incursion upon the deep seabed and exploitation of its abundant natural resources are inevitable, if not immediately imminent. The DISCOL project is currently part of an expanded research program in the Peru Basin region organized by the TUSON (Tiefsee-Umweltschutz or Deep-sea Environment Protection) Research Group. Consisting of scientists and engineers from a number of Universities and research institutions, this group is taking a multi-disciplinary approach to evaluating the potential risks and effects of human activities within the deep-sea ecosystem.

A long term, large scale, disturbance-recolonization experiment with relevance to the environmental effects of deep-sea mining is described. The study is funded by the West German government and was launched in the abyssal eastern tropical South Pacific Ocean in February-March, 1989. After obtaining pre-impact baseline environmental data, a 10.8 km² circular area of seafloor was disturbed using a specially designed "plow-harrow" device. An initial post-impact sampling series was carried out immediately after disturbance and the site was revisited in September, 1989, for renewed post-impact sampling after the disturbance. Plans call for repeated visits to the site at two year intervals in order to monitor the anticipated slow recolonization process until the area is inhabited by a new, stabilized community.

A broad understanding of dynamical principles and processes governing ocean circulation and mining exists, although a precise description is limited by insufficient observations and by limitations on numerical models imposed by computer power and inadequate knowledge of small-scale processes. Nevertheless, in many practical problems useful quantitative predictions can be made - this is illustrated by a discussion of the impact on man and the biota of low-level radioactive waste dumping in the ocean. Model results suggest that the regulation of this, or similar, dumping could be based not on limitation of the very small individual risk, but rather on the collective dose commitment. This implies an insensitivity to some details of ocean circulation, though improved knowledge of vertical mixing and geochemical processes will be required. The impact of waste disposal on marine biota at the dump site may require further research on near-source dispersion.

The fraction of pool volume filled with fine sediment (usually fine sand to medium gravel) can be a useful index of the sediment supply and substrate habitat of gravel-bed channels. It can be used to evaluate and monitor channel condition and to detect and evaluate sediment sources. This fraction (V*) is the ratio of fine-sediment volume to pool water volume plus fine-sediment volume. These volumes are computed for the residual portion of the pool that lies below the elevation of the downstream riffle crest. Fine-sediment thickness is measured by driving a graduated metal probe into a fine-grained deposit until the underlying coarser substrate is felt. Water depth and fine-sediment thickness are measured across transects, and volumes are computed by summing products of cross-sectional areas and distances between transects. Replicate measurements of V* were made in 20 pools, and the variability of V*W, the weighted mean value of V* for a reach, was analyzed in 12 reaches. The largest source of variability in V* was the measurement of fine sediment volume, topographic irregularities in pools and on riffle crests and effects of variation in discharge on measurement of riffle crest elevation also affected V*. Ten to 20 pools are needed to estimate V*w in a reach, depending on acceptable error and variability between pools.

Benthic communities adjacent to a restored beach at Hallandale (Broward County, Florida) were analyzed and compared to similar communities at nearby Golden Beach (Dade County). Five sand stations and four reef stations were sampled at each locality along a transect from the intertidal zone through the second reef. This study assesses the postnourishment condition of sandy-bottom and reef-dwelling communities approximately 7 years after beach nourishment and offshore dredging. The study also provides renourishment data for an impact analysis of a fill project underway at Hallandale in September 1979.

Core samples at sand stations yielded 114 invertebrate species not including nemerteans and oligochaete annelids. More than 90 percent of the fauna occurred at the two outer stations in densities of up to 17,144 individuals per square meter. Quadrat samples of reef biota showed a maximum abundance and diversity of corals alcyonarians, and sponges in the middle and outer regions of the second reef. The reefs appeared in good condition, and showed no apparent effects from a 1971 beach nourishment project.

Two aspects of the role of manganese in oceanic surface waters are investigated. To date, literature on the subject fails to explain ubiquitous maxima of dissolved Mn(II) concentrations measured in the photic zone. In addition, although Mn is known to be an essential micro-nutrient for aquatic organisms minimum levels toxic to marine microbial populations have not been determined results of radiotracer experiments using ⁵⁴Mn clearly show that light and natural marine dissolved organic carbon (DOC) can interact to inhibit absorption of Mn(II) onto pelagic carbonate sediment suspensions. Affinity of dissolved Mn for such part particles remains high in the dark, but much slower absorption occurs with exposure to sunlight in the presence of DOC. It is proposed that sunlight and DOC shift the partitioning of Mn within the photic zone toward the divalent species and thereby allow relatively high Mn(II) concentrations to persist in the surface ocean.

Natural microplankton assemblages were incubated using clean techniques in 4-liter polycarbonate bottles with added Mn(II). Over eight hours, RNA and DNA synthesis, adenosine 5 -triphosphate (ATP) concentrations and ¹⁴C-uptake were monitored. The data do not delineate a discrete level at which Mn(II) limits growth. Additions less than 500 parts per billion (ppb) had no effect. Additions between 500 and 2000 ppb gave erratic results, but above 5000 ppb, Mn(II) became inhibitory. A computer-generated model of a discharge plume from a manganese processing industry suggests that levels of 5000 ppb would exist in the water column only within less than 30 meters from the outfall.

DISCOL, the first large scale impact experiment in the deep sea was initiated in 1988 together with the Federal Ministry of Science and technology of Germany. After severe experimental disturbance of the seabed in a manganese nodule field in early l989, the recolonization of the benthos in the DISCOL Experimental Area (DEA) was monitored over a seven year period and compared with the baseline information on the community gained immediately before the impact. Four randomly sampled pail impact data sets were collected during RV SONNE-cruises SO 6l (immediately after the impact), SO 64 (six months Iater), SO 77 (after three years), and SO 106 (after seven years). Due to the impact, the abundances of all faunal taxa decreased significantly and, except for the bacteria, did not reach the values of undisturbed sediment half a year later. Three years after the impact, densities of the major fauna groups (mega-, macro- and meiofauna) significantly exceeded those determined for the baseline study. The sample processing for the fourth post impact investigation is still in progress, but some initial results are presented herein.

Interpretation of the animal density numbers has provided information about the start and progression of the recolonization process. Statistical analyses within major animal groups, supported by taxonomic identifications, have revealed that quantitative recovery of animal densities does not necessarily imply the recovery of the fauna composition to conditions similar to an undisturbed community. The Polychaeta demonstrated aberration in their biodiversity and in the composition of their functional groups for three years. Indicator taxa for deepsea risk assessment studies are also suggested.

To test whether deep-sea macro-fauna diversity is enhanced by specialization on small-scale food patches, we deployed colonization trays by submersible at 900-m depth for 23 d. Trays were buried flush with the seafloor to minimize potential hydrodynamics bias. Treatments included refrozen, natural sediment that was unenriched or enhanced with either Thalassiosira sp. or sargassum sp. Density comparisons and rarefaction analysis indicate that Thalassiosira sp. attracted high densities of several taxa or juvenile opportunists, and Sargassum sp. trays were colonized by fewer individuals of a more diverse fauna. Ambient faunal diversity was higher and densities lower than enrichment treatments although unenriched trays did not attain ambient densities. Results suggest that juveniles, rather than adults, specialize on specific patch types, thus contributing to high deep-sea diversity, this bottleneck may be fundamentally different from less diverse, shallow-water macrofaunal assemblages.

Mining the abyssal seafloor for manganese nodules will destroy the hard substrate and it will severely disturb the seabed and the benthic soft substrate community. Recolonization will occur from unmined areas. Reestablishment of a community similar to that originally present is, however, not possible, since the nodules will be removed and epigrowth on hard substrates is thereby precluded. Small scale experiments using azoic sediment in trays exposed to ambient deep-sea conditions, may not be appropriate models for large scale recolonization processes.Results of such experiments and general knowledge of deep-sea ecology suggest that decades may be required for reestablishment of a balanced community.

With respect to evaluation of some ecological consequences of mining an ongoing large scale experiment, termed DISCOL (DIS-turbance and re-COL-onization) is shortly described as a new approach in deep-sea risk assessment.

The actual and potential use of the deep sea for mining of metalliferous resources and for disposal of waste materials are described, potential environmental problems are elucidated, and necessary ocean research activities are presented for each of these deep-sea intrusions. The large scale or all contemplated actions and disturbances gives rise to the most severe concerns. Large-scale experimental impacts at great depths and careful monitoring of individual pilot mining and waste disposal operations are proposed for precautionary reasons. International and multi-disciplinary cooperation of engineers, oceanographers, politicians, and economists is emphasized to channel all efforts into mutually beneficial synergistic effects. It is a challenging task for all those involved to collaborate in order to further a sustainable and environmentally friendly development of deep-sea utilization. Specific responsibility and regulatory functions could be assumed by the International Seabed Authority of the United Nations.

The European Union called for proposals for "the assessment of any possible risk likely to affect the marine environment in association with research, monitoring and surveying In marine sciences and technologies". An assessment was made by a small group of deep-sea ecologists, stating that normal scale research would impact the environment to a negligible extent. Future requirements for ecological deep ocean research related to the use of the deep for waste disposal and mining or metal-rich ores were also presented. Experimental large-scale research for commercial scale impact assessment as well as pre-commercial pilot operations are discussed. It is concluded that studies of this type are still of an order of magnitude that is acceptable and unlikely to cause significant impacts.

The RISKER (Environmental Risks from Large-Scale Ecological Research in the Deep Sea - A Desk Study) report was initiated through the European Commission and addresses the question of whether marine ecological research could in itself be unacceptable from an environmental standpoint. The international study group specifically considered the environmental acceptability of conducting the research needed to assess:

• The impacts of past uses of the deep ocean for various types of waste disposal.
• The sustainability of ocean resources in the face of any future exploitation of sea-bed minerals.
• The environmental acceptability of any disposal of waste into the deep ocean for which alternative management approaches (e.g. waste minimisation, recycling and land-fill) become insufficient to circumvent environmental problems as a result of the growth of human populations and the concomitant increases in industrialisation.

Recently it has become evident that results from traditional scale sampling experiments and observations cannot be extrapolated to asses the impact of full industrial extraction of deep-sea minerals, and so recent oceanographic investigations, perforce, have had to conduct much larger scaled experiments. The question then arises as to the environmental acceptability of these experiments.

Chapter 2 is devoted to the extraction of deep-sea minerals. After a brief introduction to the mineral resources of the deep sea, a series of such chapters examine each of the major potential mineral ores which may be mined in the future Subchapters 2.l and 2.2, respectively, address manganese nodules and crusts, the major oxide minerals found in the deep ocean. Subchapters 2.3 and 2.4 review the two dominant forms of sulphide mineralisations that may become future sources of metals, namely metalliferous muds and massive consolidated sulphides, respectively. Another important mineral resource found in some shallower deep-sea areas are the phosphorites which are the subject of Subchapter 2.5. Each of these five Subchapters provides a resource description, reviews possible mining techniques, examines potential mining effects and lists the research necessary to evaluate these possible effects.

Chapter 3 addresses the past and potential use the deep ocean for waste disposal. Several categories of waste have already been disposed of into the oceans, but seldom in a manner that would meet modern criteria of acceptability. Nearly all such dumping is currently severely curtailed by international law, because it is generally considered that too little is known about the impacts, and indeed some argue it never will be justified. In spite of the current moratorium, options for using the deep ocean for certain types of waste disposal are being evaluated because of our realisation that society's ability to cope with its ever-growing waste management problems is approaching a crisis point. After a brief introduction to the disposal of wastes in the sea, the chapter is organised into a series of Subchapters. The first two discuss wastes that have been dumped in the sea in the past, but are unlikely ever to be so again (munitions (3.l) and radioactive wastes (3.2)). However, monitoring of their dumpsites are considered to be necessary, not only to reassure the public that these sites threaten neither mankind nor the long-term integrity of oceanic environments, but also to provide useful insights into what long-term impacts may result from any future ocean disposal of other types of waste. The third Subchapter (3.3) examines the environmental impacts associated with the accidental and intentional disposal of large structures into the deep ocean. The Subchapters 3.4 and 3.5 discuss the possible disposal of sewage sludge and dredge spoils, both of which can still be disposed of legitimately into deep water. It is envisaged that in the future deep ocean disposal of such wastes may prove to be the optimum waste management approach compared to land disposal, both in terms of regional and global impacts. The final Subchapter (3.6) deals with the even more thorny question as to whether the deep ocean can (or should) be used as a means to reduce the atmospheric carbon dioxide which will result from the burning of fossil fuel, and which will have predictably serious environmental impacts. Each Subchapter includes a description of the waste material, considers possible disposal techniques and examines the environmental impacts expected to accompany the disposal activities. Some methods that may be appropriate for the disposal and/or containment of sewage sludges and dredge spoils on the deep-sea floor are introduced and discussed in the sewage sludge chapter. The choice of disposal technique will make a considerable difference to the experimental evaluation that would necessarily be undertaken before any such disposal could be contemplated on an industrial scale The final section of each Subchapter therefore summarizes the research activities deemed to be necessary for the evaluation of the potential effects imposed on the environment by commercial-scale waste disposal.

The acceptability of conducting large-scale ecological research and experiments in the deep sea is discussed in Chapter 4. In the absence of internationally agreed criteria, the following have been adopted for this report:

• The objectives of any experiment can be reasonably expected to contribute towards the environmental evaluation of full-scale industrial activity.
• The impacts must be monitorable.
• There must be no persistent adverse effects on diversity at regional scales, i.e. no species will be driven to extinction, no exotic species shall be introduced, the area of destructive impacts shall be >0.1% of the area (or volume) inhabited by any community.
• The experiment must not impair any ecological processes.
• No living resources shall be adversely effected.- The experiment must not interfere with other legitimate uses of the ocean.
• There must be no critical or mass transport pathways to convey significant quantities of deleterious substances or organisms back to Man.
• Risks to human health and safety must not be increased.

The research proposed b the various Subchapters of Chapters 2 and 3 are concurrently assessed against these criteria.

The scales and nature of the research necessary to improve the assessments of environmental impacts of the full industrial scale activity for each use of the deep sea are also examined. Theserange from traditional laboratory and field observations (including monitoring) of existing impacts and oceans condition to novel large-scale experiments linked to industrial feasibility trials. The criteria of acceptability are used to assess the various scientific studies identified as being necessary for the environmental impact studies of each activity. It is concluded that the traditional scales of investigations fall well within the limits of acceptability. Impacts associated with such studies occur over a relatively small area and are negligible. For several types of waste (radioactive material, offshore installations and munitions) monitoring of existing disposal sites will provide significant information on these and other uses of the ocean, and should be given a high priority even if no further disposal is ever conducted. These monitoring activities can be carried out with traditional methods and no significant environmental effects are expected.Before any mining of the mineral resources discussed and any disposal of wastes such as sewage sludge, dredge spoils or carbon dioxide can be approved, the authors consider that it will be essential to conduct large-scale experiments well in advance of the development of full-scale operations. These would need to ascertain that the scale of the impacts will not exceed the limits of sustainability, to develop monitoring protocols for the industry, and to reassure the general public that the operations will carry a tolerable level of risk, both for the human population and the ocean ecosystems. It will also be important to conduct base-line studies to allow adequate monitoring of the operations to ensure that the actual impacts do not exceed those predicted. Criteria of acceptability remain poorly developed and their much greater sophistication will be essential for good environmental management and public acceptance.

Mining operations will involve extensive destruction or seafloor communities during the extraction of the minerals, and potentially wider impacts on the water column and sea-bed by discharges of tailings resulting from the initial processing on the mining platform. Experimental studies must be conducted at scales that can be extrapolated confidently to the scale of impact, both in space and in time, of full industrial operations. As long as the precise details of the mining technology that will be employed remain undecided, general precautionary, large-scale experiments are the means to learn about the reactions of the community to various disturbances and to be prepared for subsequent more targeted research approaches. The experiments will have to encompass studies of both the sea-floor and the water column. Since some of the open questions about impacts are identical no matter which ore is being mined (such as the behaviour of plumes and the sedimentation of tailings after discharge), many of the experiments andsubsequent verifications will be common to all mining operations and should be conducted in advance. The final study level to evaluate mining impacts will be the monitoring of pilot mining operations (PMOs).

In a similar manner, large-scale experimentation will have to be conducted prior to any disposal of wastes, freely or contained., into the ocean. In addition, better baseline knowledge of the distributions of deep-ocean biota and the factors controlling them will be required if site selection, both for the experiments and any eventual disposal, is to be carried out according to any objective scientific rationale. The experimental design will need to involve nested scales of Impact ranging from laboratory experiments to in situ experimental manipulations involving stepped increases in the volumes and delivery rates of each type of waste. Prior to each increase in experimental scale, the acceptability of the impacts will need to be re-evaluated and the decision taken whether or not to scale up the experimentation. The final experimental level will be the pilot dumping operation (PDO).

The proposal to use the deep ocean as a repository for carbon dioxide in order to keep the transient increases or atmospheric concentrations within acceptable bounds will also need experimental approaches. These should span many scales since the reactions of organisms, communities and total ecosystems to increases in ambient carbon dioxide concentrations are still very poorly understood. Two large-scale experimental approaches are envisioned: a total ecosystem experiment conducted in a semi-enclosed fjord, and an open ocean experiment involving the discharge of large quantities of solid, liquid or gaseous carbon dioxide into the deep ocean.

Few of the large-scale experimental designs considered by the authors that might be conducted to address the questions of risk assessment of industrial-scale activity approach the highly precautionary limit adopted. The basic acceptability criteria assumed are that the scale of any impact should be restricted to <.01% of any specific habitat and that no species should be driven even close to extinction. Even so, such are the uncertainties about deep ocean ecology that the thorough monitoring of any, and every, future pilot mining operation (PMO) and pilot dumping operation (PDO) which may eventually lead to commercial scale activity remains a high priority.

Deep-sea research and experimentation is expensive and requires a long-term commitment. Deep-ocean ecosystems are tuned to a very slow pace and so their response to, and recovery from experimental and/or industrial interventions can be expected to be slower than those of terrestrial and shallow-water ecosystems. Consequently, the research proposed, if it is to provide answers and not be just a ploy to persuade the public that something is being done, must be conducted over long periods of time. A start must be made well before socio-economic pressures precipitate rapid development of commercial-scaled activities in the deep-sea. The time needed clearly falls well beyond the normal range (1 - 5 years) or socio-economic developments. Sound scientifically based evaluation and guidance can only be achieved if the supporting research has been intensive enough and carried out for long enough prior to the initiation or commercial activities. Such precautionary large-scale experiments will increase the chances of resolving the global-scale environmental problems which will predictably be generated by the accelerating growth of the World population and the inevitable associated increases in demands on environmental resources (both oceanic and terrestrial). These precautionary deep-sea experiments should be given high priority.