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By C. A. Geffen

This report, sponsored by the U. S. Bureau of Mines, presents the results of an examination of the safety of the impactor shaft sinking system in comparison to conventional shaft sinking technology. Detailed study of the impactor system was also performed to identify and recommend design changes for optimum safety conditions. A comparison of the impactor machine and its support systems with conventional shaft sinking was made on the basis of relative risk levels. Risk incorporates measures of both the frequency and the potential consequence of accidents. A safety evaluation of the com¬ponent operations of the impactor shaft sinking system was performed using a Failure Modes and Effects Analysis (FMEA) methodology. The results of this analysis show generally that the impactor shaft sinking system is safer than conventional shaft sinking. The potential risk of conventional shaft sinking operations could be reduced by an average of over 35 percent with use of the impactor shaft sinking system. Design change recommendations to further improve the safety of the impactor system include a revised fire suppression system, improved access to and from the operator cabs, reliable noise attenuation measures and improved communication systems. An operational safety manual was also developed for the impactor shaft sinking system.

Jan 1, 1982

The Minerals Data Source Directory is a compilation of descriptive information on the availability, content, and location of minerals data in the Federal Government. It is intended to assist Government personnel and the general public in locating and acquiring minerals information. Included in the Directory are descriptions of data bases, publications, information systems, and information offices containing data pertaining to all aspects of mineral production, consumption, trade, and related information. These mineral data sources include the Federal agencies such as the Department of the Interior's Bureau of Mines and Geological Survey whose major mission is the collection and dissemination of mineral information. Also included are agencies such as the Departments of Agriculture, Commerce, Labor, State, and Treasury, and the Central Intelligence Agency, whose primary mission is the collection of data in non mineral subject areas, but in which the mineral industry is a component.

Jan 1, 1982

This work examined the feasibility of in-mine coal preparation in two phases. Phase I included a survey of previous investigations and a preliminary analysis of the economic and technical feasibility on a selection of representative sites and degrees of cleaning. The contract was terminated at the end of Phase I. The preliminary analysis determined that in-mine preparation systems can be applied using currently available technology. The most likely mines for application will have shaft or slope access and be deeper than 500 feet. The refuse disposal systems technically feasible are (1) pneumatic placement of coarse refuse in room and pillar panels or longwall faces, (2) mechanical placement of coarse and fine fractions in room and pillar panels, and (3) hydraulic placement of fine fractions in room and pillar panels. The economic feasibility is much more dependent on the refuse disposal-system than on the preparation system. It is estimated that the capital cost of an in-mine preparation and disposal system would be $6.00 per clean ton and the operating cost would be $1.24 per clean ton for a 1 million clean ton per year mine.

Jan 1, 1982

By E. E. Ungar

Criteria applicable to noise in coal cleaning plants are presented, and the generally applicable noise control principles and approaches are discussed. The operating characteristics and equipment of coal cleaning plants are described. Considerations entering in the selection and design of noise control means are delineated, and specific means for equipment noise reduction are described. The limited utility of acoustically absorptive materials in plant spaces is indicated, administrative means for reducing worker noise exposure are pointed out, and ear-protective devices are described briefly. The reduction of plant noise reaching nearby communities is discussed. Programs leading to quieter machines an coal cleaning plants are suggested.

Jan 1, 1974

By D. Randolph Berry

The United States Bureau of Mines (USBM) awarded a contract to Foster-Miller, Inc. to develop guidelines for the storage and use of Self-Contained Self-Rescuers (SCSRs) in underground non-coal mines. An SCSR is a device capable of supplying, in an emergency, one hour of self-contained oxygen (no breathing of mine air). The information and recommendations in this report were developed primarily from three sources: discussions with mine representatives (including management, labor, and government), site visits in underground mines I and a detailed analysis of every reported non-coal accident which produced d hazardous atmosphere during the 5-year period 1976-1980 -plus ten other major incidents from prior years. Volume IV has three major sections: Recommendations and Discussion (Section 2), Analysis of Mine Accidents (Appendix A), and a Summary of Discussions with Mine Representatives (Appendix B).

Jan 1, 1983

Electrical trailing cables are frequently damaged in usage, especially on continuous minors, and because of their weight and damaged condition present a safety hazard to personnel required to handle them. The U.S. Bureau of Mines and FMC Corporation signed Contract No. HO 122011 in August 1971. One of the contract tasks was to study the feasibility of techniques to improve trailing cable support and handling of power cables on underground coal mine machinery and to design a cable-handling device for a continuous mining machine. This report presents the results of the feasibility study, describes the design for a proposed cable handling device and concludes with a recommendation for future action to construct a test rig to evaluate the cable reel system.

Jan 1, 1972

By Virgil A. Marple

The objective of this contract was to investigate time-integrated and real-time methods for determining the diesel exhaust particulate concentration in underground mines, in particular, coal mines. The microorifice uniform deposit impactor (MOUDI) is recommended for obtaining the time-integrated measurement of the size distribution. The mass concentration of diesel exhaust particles can be obtained from the particle size distribution of mine aerosols. On a mass basis, diesel exhaust particles are primarily in the submicrometer size range while coal dust particles are larger. Size distribution measurements made in the laboratory and in three underground coal mines exhibited two distinct modes with the diesel exhaust particles in the smaller particle mode and the coal particles in the larger particle mode. The point of separation between the two modes occurred in the 0.7 to 1.0 pm size range. The separation was found to be independent of mass fraction of the diesel exhaust particles, particle concentration and sampling site. Methods recommended for further consideration as real-time monitors of diesel exhaust aerosols in mines are photometers and filter pressure drop techniques. A preclassifier would be required in both cases to separate the larger dust particles from the sample. The Metrex Mineral/Diesel Photometer should also be investigated further once the electronics problems are eliminated.

Jan 1, 1986

By Joseph M. Kurtak

The Bureau of Mines is currently conducting a four year mineral assessment of the 5.7 million acre Valdez Creek Mining District in Southcentral Alaska, as part of its ongoing statewide mining district evaluation program. This report is a summary of the 1987 field work, which included the examination of mines, prospects, and mineral occurrences in the study area. Placer gold has been the most important metal produced in the area, and production totaled 161,131 oz, with the majority of the production coming from the Valdez Creek Mine. Lode gold and silver production totaled 1,581 oz and 8,617 oz, respectively and came mainly from the Golden Zone Mine. Varying amounts of other metals, including copper, lead, zinc, molybdenum, antimony, chrome, nickel, cobalt, tin, tungsten and platinum exist in the study area. Occurrences of industrial limestone and coal are also located in the area.

Jan 1, 2011

By R. V. Ramani

One area of study in the Coal Mine Injury Analysis project was to illustrate and enhance the ability of mine safety management personnel to apply analytical techniques to injury experience data and to justify requests for funds for safety enhancement actions on a cost/benefit and other quantitative basis. Four volumes of this final project report detail (1) the objectives and scope of the mine safety management research, (2) the results of literature review, and case studies, and (3) models developed for mine safety management. The four volumes are titled as Volume III: Mine Safety Management, Volume IV: Analytical Techniques for Mine Safety Management; Volume V: Mine Safety Management Case Studies and Volume IX: Training Cost Model. In this volume, the quantitative procedures that have been developed for the mine-specific analyses of accident/injury experience data are presented and their applications are demonstrated in a summary form through case study examples. The quantitative procedures will aid mine safety management personnel to develop focused accident prevention strategies including training, as well as to justify the investment in such proactive programs through cost-benefit analyses.

Jan 1, 1993

By D. D. Southworth

In 1981, 1982, and 1983, the Bureau of Mines examined the potential for lode deposits of platinum-group metals (PGM) in the Goodnews Bay ultramafic complex, Alaska. The complex consists of the Red Mountain, Suzie Mountain, and Smalls River ultramafic bodies and displays concentric zoning of rock types similar to complexes in southeast Alaska, British Columbia, and the Ural Mountains in the U.S.S.R. Results of the study indicate that platinum is preferentially associated with chromite and magnetite in the dunite core of the complex, and palladium is preferentidlly associated with sulfide minerals in the outer clinopyroxene-rich zones. the most promising targets for PGM lode deposits are the chromite-rich dunite at the heads of Fox Gulch and Squirrel Creek and iron-nickel and iron copper sulfide-bearing magnetite clinopyroxenite and hornblende-rich rocks outward of the dunite core, also in the Fox Gulch-Squirrel Creek area. Significant placer reserves are present in the unmined, deeply buried placer ground in the lower Salmon River Valley, and also in tailings from previous dredging.

Jan 1, 2011

By C. A. Hesse

The Quartz Hill Molybdenum Project, In Southeast Alaska, was the first mining project to attempt the permitting of a submarine tailings disposal system in the United States, since the passage of the National Environmental Policy Act of 1969 and the Clean Water Act of 1977. Over $20 million was spent by the project developer in baseline data gathering and In funding the preparation of the four Environmental Impact Statements and other environmental documents required at various stages of the project between 1977 and 1988. Because of the timing and a unique set of environmental, legal and regulatory requirements which applied to this project, innovative approaches were developed. This report describes those requirements and the developments, and gives a full historical account of the campaign for permitting submarine tailings disposal at Quartz Hill, until denial of the NPDES permit application by EPA in September 1 990. The extensive studies done for Quartz Hill suggested that under certain conditions the selection of submarine tailings disposal can be the overall environmentally preferred alternative for a mining project. The Quartz Hill story illustrates the complexity of the existing permitting structure and paints out the desirability of rationalization to achieve a more effective system.

Jan 1, 1993

By Frank S. Wartman

"The experimental flotation work described in this paper was undertaken to test the conclusions derived from a previous microscopic and chemical study of several samples of converter slag. That study3 resulted in the conclusion that approximately 90 per cent of the copper content of a converter slag wad in either the sulphide or metallic form, and that if the slag were cooled slowly the copper-bearing material would be in particles of such size that they would be freed from silicate and magnetite grains by grinding the slag to pass a 150-mesh sieve. If this were true, it should be possible to separate the copper-bearing grains from slowly cooled, converter slag by the flotation process.Many attempts, of which the author has seen no published account, have been made to treat slags, especially converter slags, by flotation. In every case these trials have been made with chilled slags, in which, as shown in the preceding report, the copper-bearing material is top finely disseminated, to be freed by any reasonable degree of grinding.The flotation tests described in this paper have shown that it is possible to recover by flotation about 30 per cent of the copper content of a converter slag containing 3 per cent copper and to obtain flotation concentrates which have a copper content of 35 per cent.Acknowledgment is made to G. L. Oldright, supervising engineer of the section of nonferrous metallurgy, U. S. Bureau of Mines, for valuable assistance and direction; to W. A. Sloan for chemical analyses; and to Alfred P. Towne for assistance in experimental manipulation."

Apr 1, 1931

By R. R. Lowery

This project was proposed to provide information on the hazards associated with arc melting of thorium. A general air-sampling analysis was made to determine the separation, concentration, and distribution of thorium daughter (decay) products throughout arc melting, machining, and forging processes of a thorium handling facility. The value of well coordinated health physics program is stressed in connection with potential health hazards and personnel protection. Building, equipment, and exhaust ventilation requirements for such a facility are discussed. Special handling methods are described for thorium. INTRODUCTION The Bureau of Mines at the Albany Metallurgy Research Center has been involved in handling the naturally radioactive metals, uranium and thorium, for several years. Cooperative work for the Atomic Energy Commission has been carried out with thorium metal, and as a result the concerned laboratories of the Center have accumulated experience on the hazards associated with this metal. This report details the radioactive hazards arising from the arc melting, machining, and forging of thorium.

Jan 1, 1962

By Leonard Obert

This report describes a gage which, when used with my procedure for producing strain relief, will measure the resulting borehole deformation, From the borehole deformation the magnitude and direction of the principal stresses in a plane normal to the axis of the borehole can be calculated. The design considerations, mechanical construction, sensitivity, and stability of the gage are discussed. INTRODUCTION During the past two decades an increasing mount of consideration has been given to the problem of measuring and evaluating stress in rock around underground openings. Several investigators have made theoretical and model studies of the stress and (or) strain concentrations around simulated mine openings or in structural members, such as mine pillars or immediate roof. Other investigators have developed gages for directly or indirectly measuring stress or strain, and a number of reports present the results of measurements made with these gages. Because various methods and instruments have been developed, factors involved in this type of measurement will be briefly considered.

Jan 1, 1962

By E. D. Calvert

This Bureau of Mines report discusses the electric-arc reduction of zirconium and hafnium oxides with carbon yielding a metal-metallic carbide mixture. The carbon to oxide ratio in the feed determines the metal to carbide ratio in the product. A sample of this product was produced -or testing as a feed for the deBoer iodide-dissociation process. A new technique for producing pure carbides is described, which uses the intense heat of the arc to volatilize the carbide. The condensed vapor form , crystals of nearly stoichiometric carbide, INTRODUCTION This research examines the preparation of refractory metal carbides in the controlled atmosphere electric-arc furnace.

Jan 1, 1962

By William H. Schiffbauer

The Bureau of Mines has developed a passive encoder for range knobs, a device that automates the task of obtaining the range settings from devices or instruments to be input to microcomputers. It is easily constructed and installed and will not disrupt the device to which it is being attached. It consists of a custom knob and a small printed circuit board that has light-emitting diodes and magnetic reed switches attached. A ribbon cable connects it to a microcomputer. This encoder eliminates one source of human error in an automated process.

Jan 1, 1983

By David K. Denton

Results of the mineral resource study of the Upper Priest Lake RARE II study area indicate a low potential for the discovery and economic recovery of silver and lead in the Prichard Formation near contacts with the Kaniksu Batholith in the vicinity of the Mountain Chief Mine (fig. 1). Silver and lead minerals locally occur disseminated and in irregular quartz fissure-fillings in the Prichard Formation. Between 18^6 and 1967, 105 lode raining claims were located in the study area. The area was designated for "further planning" in the Final Environmental statement but was later changed to "nonwilderness" by President Carter after work was scheduled for the area.

Jan 1, 1981

By Vance G. Leak

A technique for recovering copper and steel from metallic scrap has been developed by the Bureau of Mines based on preferential melting in molten salt baths at 1,150° to 1,250° C, The molten salt, preferably barium chloride or calcium chloride, both minimizes oxidation of the metals and promotes heat transfer. Cleanest separations (0.01 percent copper remaining in iron) have been achieved by pretreatment (dipping or spraying) with sodium sulphate or sodium silicate, which alters and coats the surface of the iron to inhibit the alloying or brazing with copper. An economic evaluation of the process was carried out on six combinations of sweating media and inhibiting reagents. On the basis of the postulated model, a cost of about $0.20 per pound of copper recovered has been determined for the sweating treatment operation.

Jan 1, 1973

By Richard H. Bares

The general or macroclimate of the study sites in western North Dakota is characterized by rapid and sometimes extreme daily and day-to-day temperature fluctuations, rainfall patterns which are erratic in spatial and temporal distribution and intensity, generally low relative humidity, plentiful sunshine, nearly continuous air movement, and a relatively short frost-free period. Of particular relevance to plant growth and productivity is the mosaic of microclimates: these microclimates are affected by landform (convex and concave surfaces); exposure; slope angle, length and aspect; soil color, texture and surface cover (litter), and vegetation cover. The most critical plant growth governing factor in this region is available water. It is determined principally by water input (precipitation) and water loss (evapotranspiration) which is increased by high temperatures, wind, and poor litter and vegetation cover. While spring and fall precipitation is generally gentle and soil-soaking summer rains frequently come in the form of intensive, soil-washing, localized convective thunderstorms of short duration. Due to the convective nature of these storms, summer rainfall is particularly affected by regional topography; southwest slopes and crests often receive more rainfall since these storms usually move in a northeasterly direction. The water loss due to runoff and consequent soil erosion arc major problems resulting from such "cloudbursts". Previous fall precipitation (September - October) when added to current seasonal precipitation (March - August) was found to be significantly correlated (r-.93) with plant production. Winter precipitation (snowfall) is relatively light as the prevailing weather is dominated by dry polar air masses from the north. The nearly continuous wind is responsible for removing snow from open exposures and depositing it in depressions and windbreaks. Although the winter precipitation is not a large component of the total annual precipitation, conservation of that which does occur would contribute to plant production during the following growing season. Generally clear skies over the region facilitate receipt of abundant sunshine at the earth's surface. While good for early season soil warming and plant photosynthesis, this abundant sunshine coupled with long days and nearly continuous wind is responsible for evapotranspiration exceeding precipitation by an average of six inches between June' and September. On a local (micro) scale, the water deficit is most severe on the southern exposures which receive the most direct (most effective) solar radiation and therefore are warmer than other exposures. On a broader scale, it was found that ambient temperature extremes were slightly but significantly greater in the town of Beulah in the Knife River Valley than at the upland test sites, This may have been due to the difference in topography and/or the "urban heat island" effect. It is known that air temperatures in large cities may be 2° to 4°C higher than that of the surrounding countryside. It is also well known that basins, depressions or valleys are sinks for cold air masses and are often subject to frosts not occurring on adjacent upland sites.

Jan 1, 1982

By Gary A. Kingston

Rolled steel, steel forgings, and steel castings in the Pacific Northwest (Washington and Oregon) are produced principally in the Seattle, Wash., and Portland, Oreg., metropolitan areas. Steel-mill products are rolled from carbon and some alloy &eels by three companies into shapes such as reinforcing bar, rods, rounds, squares, flats, and hot-rolled strips; structural shapes, - such as angles, channels, and I-beams, also are rolled. Carbon and alloy steel ingots are poured and forged at a Seattle plant into ship shafting, drive shafts, billets, slabs, bars, rings, hooks, and other items. Static, shell, investment, and centrifugal castings are produced at 19 steel foundries in a wide range of steel specifications. All Pacific Northwest steel output is based on remelting steel scrap. Local iron ore might be used in the future to supplement steel scrap as a metal source. Ore reduction would probably be achieved by methods other than the blast furnace. Current melt-shop practice and problems are basically the same in Pacific Northwest steel plants as in cold-melt shops in other parts of the country. Quality steel production is receiving more emphasis in this region with the installation of modern analytical equipment and vacuum pouring and melting facilities.

Jan 1, 1962