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By T. J. Smolik

The Golden Sunlight Mine started full-scale operations in February 1983, with a conventional open-pit mine supplying 4464 tonnes (5000 tons) per day of milling ore. After crushing and grinding, the ore is leached with cyanide solution in large agitation tanks. Soluble gold values are removed from the sand portion of the leached ore with five stages of countercurrent washing cyclones. After thickening of the cyclone-wash overflow slurry, the gold is recovered in activated carbon with a six-stage carbon-in-pulp circuit and a five-stage upflow carbon column circuit. Pressure stripping, carbon reactivation, electro-winning and refining complete the gold recovery process.

Jan 1, 1984

Crushing and grinding The Crushing and Grinding Technical Committee There was substantial activity in the area of crushing and grinding with the improved outlook in the industry. The Crushing and Grinding Committee's theme of 1987's Annual Meeting in Denver was Fundamentals of Mechanical Design for Crushing and Grinding Mills. At the meeting, the concept of gearless sag mill variable speed drives was taken out of the closet, dusted off, and a wraparound motor was put on hard copy with the ordering of a 9.7- x 4.5-m, 8.2-MW (32- x 15-ft, 11,000-) sag mill. Additionally, comparisons were provided to the mill design of the gearless drive sag mill and the twin 4.5 MW (6000 hp) do variable speed drives placed on the drawing board for the Kennecott UCD Expansions. This involved a 10- x 4.5m, 8.9 MW (34- x 15 ft, 12,000 hp) sag mill. Differing opinions were also expressed in technical presentations pertaining to the need for quality mill specifications in design and manufacturing. J. Berney-Ficklin of Bechtel presented a paper outlining the need for quality design and manufacturing specifications in large scale grinding mills, and the overall cost reduction in capital and operating costs. Others presented differing specific views, but all emphasized a central theme. Quality and reliable designs in large mills should not be compromised. In-pit crushing applications continue to increase, overseas and in the US, in both mining and quarrying. Different in-pit crushing units have been classified as mobile, with integral transport systems; semi-mobile, typically modular systems that use separate transporters for repositioning; semi-stationary plants that must be dismantled before transporting and typically require earthwork and concrete foundation work; and stationary in-pit crushing plants, which remain in place for the life of the pit. The majority of equipment sales of conventional crushing and grinding circuits in 1987 were to gold mining operations. There have been two areas of end use: • conventional jaw/gyratory or impact crushing circuits preparing low grade ores for heap leaching; and • small scale sag/ball mill circuits preparing higher grade ores for classical cyanide leach/ recovery circuits. There was also continued interest in ABC and SABC circuits for both base and precious metals plants. High pressure roll crushers continue to attract considerable interest in the cement industry. There, they are used to prepare raw materials or clinker for subsequent ball/tube milling. However, they have apparently been less successful in the mineral industry where the energy savings/ capacity gains have been much less dramatic. Several papers covering the theory and application of these machines were presented in an industrial minerals session on cement at the SME Annual Meeting. The Third International Conference on Hydrocylones, held in England in October produced several papers of interest on classification and screening to the mining industry. In particular, a new cyclone apex, developed by Mt. Newman Mining, shows promise of reducing water flow to the cyclone underflow stream and, therefore, increased underflow pulp densities and reduced fines recycle in grinding circuits. A twin vortex hydrocyclone was also described and shown to give a sharper split than conventional units. Similar double cyclones were introduced in the 1950's, but failed to achieve widespread acceptance. This was due mainly to a proneness to blockage in the transitional zone. It will be interesting to see whether this latest variant can overcome this problem in the typical operation. A number of North American iron ore plants installed the capability to produce fluxed iron ore pellets. Most chose to grind the stone on site with circuits designed to grind taconite ore. Methods employed to grind this material included single-stage ball mills closed with fine screens, rod and ball mill circuits - both open and closed with cyclones - and semiautogenous mills, followed by ball mills closed with screens or cyclones. Dewatering and tailings disposal B.M. Moudgil and D.L. Sober, University of Florida Due to tightened environmental regulations and the need for more efficient land use, a greater interest in dewatering and waste disposal has developed. As a result, research efforts in flocculation, surface chemistry, and polymers science have focused on the problems related to the dewatering of solid mineral wastes. A few studies have been conducted to examine the flocculation process. Hogg et al., (1987) discussed the formation and growth of flocs. They determined the size and density of flocs was controlled by the physical conditions of the system (e.g. agitation,

Jan 5, 1988

By D. C. Torre

The coal mining industry has long recognized the need for a system capable of hauling mined coal from the face in a continuous flow. More than 30 years ago, successfully operating continuous haulage systems were first placed in the field. There were a few individually successful applications. However, the truly successful use of such systems really only began in the early seventies. Today, a variety of systems are available from a number of manufacturers. Even so, continuous haulage has not achieved the acceptance and application it would seem to have earned. There is a need for more productive, cost-effective, and safer methods of hauling coal from the face. There is also a need to speed up development for longwall operations. And continuous mining is not really "continuous" unless it is supported by a reliable continuous haulage system. Despite all this, most of the coal producers have failed to exploit the successful continuous haulage systems offered by several manufacturers. In the 1970s, many of the top coal producers tried a continuous haulage system but gave up on it and on the concept. In some cases, major coal companies had systems operating successfully in one mine, or even one division. But their use did not spread to others of their mines or divisions. Frequently, their use was eventually abandoned, even in mines where it had been successful.

Jan 1, 1990

By Yi Luo, Hua Jiang

A roof bolting drilling operation in an underground coal mine can expose the operator to a high concentration of respirable coal and crystalline silica dusts (smaller than 10 µm). Overexposure of high-level quartz dust for a roof bolter operator can lead to the development of silicosis in as little as three years [1]. This study proposes a drilling control algorithm for the bolt hole drilling process. This algorithm can be integrated into a current drilling control system on the roof bolter machinery and is expected to reduce the generation of respirable dust while enhancing the energy efficiency of the roof bolter machine. In addition, the drilling efficiency and bit condition can be evaluated while drilling based on the real-time feedback parameters. This capability enables the algorithm to ensure the drilling is performed under a relatively high energy efficiency with less respirable dust generation and to avoid drilling with an excessively worn bit that can cause bit clogging or steel buckling failure.

By Yuanhong Qi, KUN CUI, Tao Fu, XUNFU WANG, Yingyi Zhang, Jie Wang, Junmao Qie

Indonesia is the world’s largest supplier of nickel ore, with its nickel laterite resources mainly distributed in the Moluccas and Sulawesi regions. However, there is scant research on the mineralogical characteristics of nickel laterite deposited in southeast Sulawesi, Indonesia. This study aims to investigate the mineral phase structure, chemical analysis, thermal properties and element distribution characteristics of the middle and lower part of the rotten rock zone located in the southeast Sulawesi ophiolite belt.

By R. B. Hawkins

The discovery of the gold deposits of the Jerritt Canyon district and the construction of the E. R. Bell Mine is one of the significant mining developments in the United States during the past ten years. This mine will exploit one of the larger deposits of disseminated gold presently known, with proven, recoverable reserves in excess of 67.6 million grams of gold. Interest generated by the success of this project has contributed greatly to the tremendous resurgence in exploration for disseminated gold deposits in Nevada and throughout the west. The Jerritt Canyon project, including the Bell Mine, is a 70/30 joint venture between Freeport Gold Company and FMC Gold Incorporated, both of which are wholly owned affiliates of the respective parent companies, Freeport-McMoRan, Inc. and FMC Incorporated. Under the terms of the joint venture agreement, Freeport Exploration Company, another Freeport-McMoRan affiliate, manages the exploration and pre-mine development. Drilling, design, construction and management of the Bell Mine are provided by Freeport Gold Company.

Jan 1, 1982

By A. M. Marabini, G. Belardi, V. Alesse, M. Acosta

Sotiel mine is situated in the Iberian Pyrite Belt in southern Spain, some 40 km north of the port of Huelva. Although mining operations at the site date back to Roman times, the present mine came into production in 1983 and 5.6 million tonnes of ore had been extracted by 1993. The orebody is volcano-sedimentary and consists of fine grained copper, lead and zinc minerals in massive pyrite surrounded by slates and volcanics. Prior laboratory research had resulted in the synthesis of a new collector, belonging to the MercaptoBenzoOxazole (MBO) class that acts selectively towards Cu and Zn minerals after activation with CuS04. The MethylMercaptoBenzoOxazole (MMBO) version of this collector had been used for the laboratory flotation of Cu minerals and sphalerite activated by CuS04. This resulted in identification of the optimal physicochemical conditions for laboratory-cell flotation of the two minerals from samples of complex sulphide ores, and subsequently the reagent has been tested in the Sotiel plant (Spain). The plant has three flotation sections. With conventional re-agents, the first section yields a Cu concentrate grading 21% with a total recovery of 29%, and the second one yields a 40% Pb concentrate with total recovery of 34% and a 47% Zn concentrate with total recovery of 78%. Application of the new synthetic reagent in the copper and zinc circuits produces a more selective process with a decrease in re- agent concentration grade and recovery are increased by 2 and 9 points respectively in the case of Cu and by 1 and 3 points where Zn is concerned. Moreover, the penalty elements in the Cu concentrate are halved.

Jan 1, 1995

By Warren C. Gerler

An overland belt conveyor system is installed for only one reason to save money. It must pay its way on a ton-mile basis over a stated period of time, and do so in competition with other forms of transportation. Such a system with its economies has recently been installed at Simco-Peabody's mine near Coshocton, Ohio by Link-Belt Company. Three miles in length, this system carries coal from open pit and underground mining facilities to the Conesville Power Plant of Columbus & Southern Ohio Electric Company. The coal was formerly trucked from the mine direct to the power plant; but over the years the mining operations have moved progressively farther and farther from the plant, making the over-the-road hauling distance correspondingly greater. Simco-Peabody has mining operations over a considerable area just east of the Conesville Station. The majority of the coal is recovered by conventional strip mining. Some underground mining` is performed by the high wall method.

Jan 1, 1963

By G. M. Smith

Several significant past and present producers of high grade and bulk tonnage gold ore from southeastern California and southwestern Arizona can be empirically and genetically linked to regional peraluminous magmatism which occurred during the late Cretaceous and early Tertiary. Geological relationships and geochemical characteristics from the Fortuna Mine area will be described and compared to those of the Tumco Mines area. Each of these historical gold producers is viewed as a morphologic end member in otherwise genetically linked metallogeny. Cold-quartz veins at Fortuna can be directly linked to peraluminous pegmatites both physically and mineralogically. Silica-magnetite±spidote±garnet rock which occurs as relatively barren, discontinuous, foliation- parallel horizons at Fortuna, but as high grade gold ore at Tumco, is interpreted as replacement of calcareous units during the same episode of peraluminous magnatism responsible for the gold vein mineralization. Whole rock and trace element data from pagmatites and aplites of the Fortuna and Tumco areas, together with data from the Gunnery Range batholith of southwestern Arizona, indicate that the magma series (after Keith, 1984) responsible for the gold metallogeny is peraluminous calcic, and is quite rich in sodium.

Jan 1, 1987

By Jr. Kermit Allen

A study was conducted for the AEC to determine the feasibility of constructing an unsupported 315 foot diameter spherical cavity at a depth of 2,700 feet in a salt dome. A cavity of this size and shape has never been attempted. It was determined that the three basic essentials for solution mining; adequate salt, fresh water, and a means of brine disposal were available at the Tatum Salt Dome in Lamar County, Mississippi. Assuming a large, unsupported mined opening of the size and at the depth required would remain stable, the most practical method of providing the cavity using solution mining techniques is by use of a movable blanket of air to control the water level to properly shape the cavity while removing the insolubles either with jetting or by conventional mining methods. It is estimated that, using the jetting method of insolubles removal, the cavity can be constructed in 24 months for approximately $7 million. Using conventional mining techniques to remove the insolubles and shape the final cavity, it is estimated that the cavity can be constructed in 36 months for approximately $12.6 million.

Jan 1, 1968

By R. V. Ramani, S. Shankar

The phenomenon of re-entrainment is seen in environments such as sand dune formation, soil erosion, fugitive dust emission and the spread of radionuclides from accidents involving nuclear weapons. A thorough review of existing literature reveals that work on re-entrainment of dust in mine atmospheres is scant. The present study was undertaken as a part of ongoing research at the Generic Mineral Technology Center on Respirable Dust at the Pennsylvania State University on the development of methods to predict ambient dust concentrations in mine atmospheres (Ramani, 1983). The contribution of re-entrainment to the spatial and temporal concentration of dust in mine airways is being studied. The research has included wind tunnel and in-mine studies. A set of seven experiments was performed under controlled conditions in the US Bureau of Mines' Lake Lynn Laboratory mine. Two types of source coal dust, anthracite and bituminous, were subjected to various airflow rates and were subjected to walking by two different individuals. Six sets of instruments were used along the test section for sampling airborne particles. The average air velocity just above the coal dust bed varied between 2.1 to 3.2 m/sec. Due to re-entrainment as a result of the airflow conditions, the average respirable dust concentration in the center of the mine airway increased to 0.09 mg/m3 (standard deviation = 0.03 mg/m3) from an initial value of 0.02 mg/m3. The concentration of all (total) airborne dust increased to 0.17 mg/m3 (standard deviation = 0. 10 mg/M3) from an initial value of 0. 02 mg/m3. The action of people walking, however, caused higher amounts of re-entrainment. The average concentration of respirable and total dust at the center of the mine airway increased to values of 0. 28 mg/m3 (standard deviation of 0.12 mg/m3) and 1.53 mg/m3 (standard deviation of 1.0 mg/m3), from initial values of 0.03 and 0.05 mg/m3, respectively. It was observed that the dust concentrations were much higher near the floor, immediately at the end of the coal-dust bed. Depending on the level of activity and the amount of dust deposited in the mine airways, re-entrainment may become an important source of airborne dust in areas away from the point of actual mining.

Jan 1, 1996

By Isabel F. Barton, Eytan Bos Orent, Mark D. Barton

A new examination of tabular uranium (U)-vanadium (V) deposits within the La Sal district places mineralization in the context of the complex fluid flow history that has occurred in the Paradox Basin and Colorado Plateau. As the only currently producing district of this deposit type in the region, the La Sal district provides excellent opportunities to study deposit- and district-scale features that can serve as exploration guides where exposure is limited. The absence of major structures along a narrow and elongate mineral trend that runs E-W across the southern part of the Utah-Colorado border indicates a regional lithologic control. The trend was likely influenced by Jurassic drainage patterns, as indicated by paleocurrent directions shown in Fig. 1. Fluvial sandstone host rocks in the Jurassic Morrison Formation contain significant evidence of multiple superimposed fluid systems that have progressively changed local mineralogy. Apart from the presence of ore minerals, remnants of fluid systems are preserved as cements including quartz overgrowths, compositionally distinct carbonates, and sheet silicates. New geochronology methods provide constraints on the timing of initial mineralization and later remobilization. U-Pb ages of calcite associated with ore minerals provide evidence for Early Cretaceous mineralization, whereas textures and K-Ar ages show that early-formed V-minerals were replaced at the expense of V-bearing micas and clays during the Eocene. The paragenesis of minerals in U(-V) deposits of the La Sal district reflects the complexity of a sedimentary

Feb 1, 2025

By Lawrence K. Nordell, Vinit Sethi

Published standards and specifications do not adequately cover engineered class pulleys for modern high strength steel cord belt conveyors. This paper discusses the Conveyor Dynamics, Inc. (CDI) design criteria and stress analysis techniques emphasizing the finite element method (FEM), fatigue failure criteria, design limits and manufacturing requirements to ensure successful and safe pulley installations.

Jan 1, 1993

By E. G. Joe

Introduction Uranium mining has been actively carried on in Canada for over twenty-five years mainly in Ontario at Elliot Lake in Bancroft, and in Northern Saskatchewan at the operations of Eldorado Nuclear Ltd. During this period, approximately one hundred million tons of mill tailings have been created and lie mainly on the surface close to the mining and milling installations. If all of the present reserves of uranium ores in Canada are mined, a further eight hundred million tons of mine tailings could be created in Ontario, Saskatchewan, the Northwest Territories, Labrador and British Columbia. The present control of effluents from existing tailings is managed by the operating mines under the regulations of both federal and provincial control agencies. It is the long-term effect of these tailings on the environment that has not been clearly defined or measured. Several years ago, the Canada Centre for Mineral and Energy Technology of the Department of Energy, Mines and Resources, embarked upon a program of research directed at the long-term effects of uranium mine tailings. Much of the research to date has been on tailings in the Elliot Lake, Ontario area where some tailings piles have existed for over twenty years. The program consists of two projects, one to address the problem of existing tailings and the other to examine alternatives in the management of current and future tailings. TAILINGS CHARACTERISTICS Uranium tailings are generally the result of sulphuric acid leaching in which the uranium and alkaline minerals such as carbonates and chlorites are leached out. If the ore contains sulphides, these minerals potentially present an additional hazard of acid generation over time and could increase the mobility of heavy metals and some radionuclides such as thorium-230. Except for the extracted uranium, most of the radionuclides from the ore remain in the tailings pile. Uranium ores in Canada span a wide variety of mineralization and associated gangue composition. Uranium minerals include pitchblende, uraninite, uranothorite, brannerite and the phosphate uranium minerals autunite and saleeite. Gangue minerals vary from acid consuming carbonates, and chlorites to acid producing sulphides and inert silicates. With such a wide variety in ore composition, the characteristics of the resultant tailings in Canada are in many cases site specific and the solutions to the long-term effects of these tailings may also be site specific.

Jan 1, 1980

"Increasing demand and market economics have pushed the mining industry to adopt improved mining practices and minimize losses. Simulation, in this regard, has proved to be an efficient tool to help in decision making purposes. We present the development of a discrete event simulation model for a large-scale open pit mine to run experimental scenarios for near optimal decision making. A mixed integer linear goal programming (MILGP) optimization model is also presented for shovel allocation optimization. The mathematical model will be coupled with the simulation model at the dispatching stage for shovel allocation optimization and thus it will act as the link to optimal short-term schedule to assist in achieving better mine plan compliance across short-term and operational planning time horizons. The main contribution of this work so far is the development of the MILGP model and development, implementation and verification of the simulation model on a large scale oil sands open pit mine case study. The results obtained so far are promising and have been validated against the historical data of the mine, proving the applicability of the model for experimental scenario analysis. INTRODUCTION It is essential for mining operations to adopt efficient operational methods and technologies to cope with market demand and economics. Mining operations, on the other hand, being capital intensive, find it risky to bring in any changes. Simulation is a tool that can help in this regard for better decision making purposes with an improved and quantitative measure of confidence. A true representative model that satisfies the objectives set for the simulation is essential to achieve its applicability for decision making purposes. A similar simulation model is presented in this paper for analyzing the operational KPIs of a large scale oil sand open pit mine with truck-shovel operations. This paper is aimed at providing an overview of the development of the model and the statistical outcomes validating its applicability for experimental scenario runs and thus for better decision making purposes. A mixed integer linear goal programming (MILGP) optimization model is also presented in this paper that acts as an upper stage in a multi-stage dispatching system. The optimization model is proposed to be linked with the dispatching logic in the simulation for optimal shovel assignments and target productions by reading available mining faces directly from the short-term extraction schedule. This model is aimed at bridging the gap between operations and short term extraction schedule; and may help achieve better compliance between the two."

Jan 1, 2015

By P. J. Tarkoy

To successfully bid a tunneling contract by machine, a contractor must have a reliable estimate of expected penetration rates and cutter costs. Preferably, these predictions should be independent of those supplied by machine and cutter manufacturers. Therefore, a series of rock index tests have been developed and incorporated in routine Rock Mechanics testing for the purpose of predicting rock boreability. Index properties were evaluated empirically by using rock samples and pertinent construction records from recently machined tunnels. Samples were taken from the completed tunnel walls, tested parallel to machine penetration, and results were compared to localized rates of penetration. Indices are based on two measures of rebound hardness and two measures of abrasive properties. The Shore (C-2 type) Scleroscope and Schmidt (L-type) Hammer were utilized to measure rebound hardness and a Taber Abraser was modified to measure rock abrasiveness and abradeability. Results indicate that rock hardness index properties investigated in this study can be used successfully to predict TBM penetration rates.

Jan 1, 1974

By Mark J. Schultz, William J. Francart, Gary J. Wirth

Atmospheric Monitoring Systems (AMS) utilizing carbon monoxide sensors have demonstrated their superiority over thermal type fire sensors for early fire detection in underground coal mines. After proving their capability and dependability throughout the 1980's, systems are now evolving and applying new technologies to enhance their effectiveness and reliability. The use of AMS in coal mines which utilize diesel equipment presents unique obstacles. Exhaust gases from diesel equipment not only raise mine ambient CO readings, but also cause numerous nuisance alarms. Both of these conditions reduce the effectiveness of the AMS. New technologies, such as discriminating devices, smoke detectors, and time delays, as well as administrative controls, have been developed and are being utilized to help reduce nuisance alarms produced by the diesel exhaust. This paper will discuss these technologies and administrative controls which are being utilized in coal mines to enhance the effectiveness of the Atmospheric Monitoring Systems. Reference to specific products does not imply endorsement by the Mine Safety and Health Administration.

Jan 1, 1995

By Ke Yang

In Chinese coal mines, extraction of deep, highly gassy soft coal seams sandwiched between soft floor and soft roof in complicated geology is commonly encountered. How to safely and efficiently excavate such seams is a very significant and important problem. It has been a focused research area in recent years. By combining the characteristics of fully mechanized longwall mining methods such as large cutting height and mining along the dip, an integrated method and technologies for the Zhangji Coal Mine were developed. This technology includes the design of a complicated geological exploration system, optimization of mining method and working face parameters, control of rock pressure and high levels of gas, reliability model of the production system, and selection and compatibility of equipment. Engineering practice shows that the integrated technology was successful in mining these complicated seams. This study not only enriches the mining method, but also improves the coal mining practice, especially ensuring both safety and productivity under complicated geological conditions.

Jan 1, 2009

By Christopher Haycocks, Lawrence P. Johnson, George M. Neall, James M. Townsend

INTRODUCTION Conventional roof support methods such as mechanical and resin bolting provide adequate support for a wide variety of coal mine roof conditions. However, roof falls remain the single largest cause of death and injury in underground mines and seriously hamper production in many operations, demonstrating that these methods of roof support are not universally effective. One of the most recent and successful advances in coal mine roof control has been the introduction of the roof truss. Although past work on roof trusses (Gambrel1 and Haynes, 1970; Sheory, et al, 1973) shows little quantification of this support technique, numerous field examples have been cited where the truss effectively supported roof which could not be controlled by either mechanical or resin bolts (Kegel, 1969). The truss combines the advantages of both inclined roof bolts and post-stressing the roof. However, the full benefits of roof trusses will only be realized when design criteria to optimize support capacity are determined. The number of trusses required for a given roof condition can then be minimized, reducing installation time and making them economically more feasible. The purpose of this research is to develop roof truss design criteria based initially on laboratory studies of gravity-loaded multi-layered photoelastic mine models. Laboratory test results will then be modified where necessary following future field testing. The ensuing relationships should provide the field engineer with a reliable means of calculating optimum truss configuration, capacity, and spacing for a set of known roof conditions.

Jan 1, 1977

By V. Anthony Cammarota

MINERALS INFORMATION PROGRAM Mineral data collection by the Federal Government actually began in 1882 with an appropriation by Congress to the U.S. Geological Survey (USGS). Although the Bureau of Mines was instituted in 1910, it was not until 1924 that the collection, interpretation, and dissemination of worldwide information on production, consumption, and availability of minerals became the responsibility of the Bureau. The objective of the Bureau's minerals information program is to maintain and provide reliable, timely, and comprehensive data for analysis of national minerals problems. This program is implemented by a staff of specialists who cover about 100 mineral commodities and the mineral industries of 168 countries. Data are also provided on the minerals industry on the State and county level. The specialists analyze information to identify trends and problems, forecast future U.S. and world supply and demand for the nonfuel minerals, and relate trends and developments to their impact on the domestic minerals industry. Data Sources and Publications The primary sources of data concerning the domestic minerals industry are the companies that produce, use, and trade in these minerals. Approximately 60,000 survey forms are sent to industry, on a monthly, quarterly, semiannual, or annual basis, to obtain the data. Domestic trade data are provided by the Bureau of the Census, U.S. Department of Commerce. Information on mineral developments abroad is developed by Bureau specialists from mineral reports supplied by U.S. embassies worldwide, from primary source documents, from a review of the technical mining literature, and from onsite mine and plant visits in foreign countries. The information is disseminated through a number of Bureau publications: "Mineral Industry Surveys" provide aggregated data on a monthly. quarterly, or semiannual basis to give timely information on the most important mineral commodities. "Mineral Commodity Summaries," published each January, provides preliminary annual data on supply and demand and discusses significant events of the previous year. The final data are published later in the "Minerals Yearbook," which is the definitive historical record for mineral statistics. "Mineral Facts and Problems," an encyclopedic work issued every 5 years, covers industry structure, technology, supply-demand analysis. economic factors, reserves, and forecasts of U.S. and world demand for individual commodities. "Mineral Perspectives" and "Mineral Issues" cover important international mineral developments and significant issues of current U.S. policy as they relate to minerals. Discussions and analyses of mineral trends and developments also appear in other Bureau publications, such as "Minerals and Materials" and "Information Circulars." These publications provide the basis for analysis and policy determinations by the Bureau and by virtually every Federal agency concerned with minerals, defense issues, the national economy, and foreign relations. The data are also used by industry in planning capital investments in mines and processing plants, by financial analysts, by U.S. delegations in their work with international commodity groups, and by a host of other minerals related organizations. Data Bases The data bases used by the specialists for preparing publications or in response to a continuous stream of inquiries include both those that contain individual commodity data from respondents, and those that are summary data bases on production, trade, capacity, employment and a number of other minerals-related items, not all of which are derived from data reported to the Bureau of Mines. The data bases maintained on the mainframes are not accessible by non- Bureau users. A 10-year data base of supply- demand data, published each year as an update of tables that appear for each commodity in Mineral Facts and Problems, is available on a floppy

Jan 1, 1987