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By Edward A. McClatchie

A methane monitor that complies with 30CFR75.313 has been designed and fabricated using a novel pressure modulated infrared absorption technique. The methane monitor met or exceeded in performance all of its target specifications. The monitor was operated continuously during production mining for the entire duration (45 days) of the in-mine test; no failures occurred during the test. The monitor was regularly checked with calibration gas and no shifts in calibration were found during the in-mine test. Operating principles, performance data and electrical schematics are included in the report.

Jan 1, 1976

By Madan M. Singh

This report presents the results of an investigation of inclined roof bolts, anchored over pillars, in room-and-pillar coal mines susceptible to shear failures of the roof. Although the field data do not support this contention, it is believed on the basis of analyses and other work that inclined roof bolts do offer potential under some circumstances.

Jan 1, 1978

By Kevin Malone

Mercury, or quicksilver as it is often called, has many applications in modern technology. Used principally in electrical apparatus, industrial contol instruments, insecticides and fungicides, electrolytic preparation of chlorine and caustic soda, chemical processes, pharmaceuticals, and dental preparations, the liquid metal has unusual properties that make it a preferred material for many industrial uses. United States consumption of mercury during the past 40 years shows a rising trend. In all except 4 years, U.S. production has been less than the domestic requirement, and imports, principally from Spain, Italy, and Mexico, have supplied most of the deficit. After World War II, domestic output decreased rapidly until 1950, when it was the lowest in the 100 years covered by production records. Higher mercury prices since 1950 have reversed the decline in domestic output and reduced the gap between U.S. production and consumption. Domestic output in 1958 was the highest in peacetime since 1883; however, the nation still imported 28 percent of its mercury requirements from 1950 to 1960 the price of mercury was high as a result of industrial applications of the mercury cell, the impact of the cold war and the Korean war, and the Government stockpiling program. The stockpiling program, in effect, put a floor under mercury prices even though only 9,428 flasks of domestic mercury went into the stockpile under the original program which ran from July 1954 to December 31, 1957. Under an extension of the program, an additional 17,463 flasks was purchased.

Jan 1, 1962

By R. W. Watson

In January 1980, the Bureau of Mines initiated an experimental program to examine the fire and explosion hazards of one-hour self-contained self rescuers (SSRs). This action was prompted by a growing concern on the part of government and industrial safety officials over the potential hazards of these devices when deployed on a large scale in underground coal mines. Prior evaluation of the safety of these devices had been at best sporadic and usually limited to experimental models. The recent availability of preproduction models of a l-hour SSR fabricated by the Mine Safety Appliance Company* and a production model manufactured by Dragerwerk Ag Lubeck of the Federal Republic of Germany allowed for a more comprehensive and meaningful evaluation of their safety in underground coal mines. This report summarizes the results of a 5-month study of the potential hazards of these two items. During the course of the work, periodic progress reports were presented to officials of the Mine Safety and Health Administration and various mining organizations including the American Mining Congress, Bituminous Coal Operators of America. National Independent Coal Operators Association, and the United Mine Workers of America. The free exchange of ideas that occurred during these meetings had a significant impact on the direction of this study and a serious attempt was made to address all of the issues that were raised at these meetings. The authors are extremely grateful to the individuals that participated in defining the specific problems that could arise as a result of deploying the self-contained self rescuers in an underground coal mine environment.

Jan 1, 1980

By Carl Rampacek, W. A. McKinney

The feasibility of leaching calcareous and siliceous oxidized copper ores by downward percolation with dilute acid was investigated in the laboratory and in a small continuous plant operated by the Federal Bureau of Mines . The crushed ore was leached in deep columns with solutions containing 1 or 5 percent sulfuric acid to dissolve the oxidized copper . Bench - scale laboratory tests on two calcareous ores from the same deposit indicated that a maximum copper extraction , about 72 percent , could be expected from heap leaching a feed as coarse as 1 inch . Laboratory tests on a siliceous ore showed that almost 70 percent of the copper could be extracted by leaching a 1 / 4 - inch feed . The bench - scale tests were supplemented by larger continuous runs wherein the copper was recovered from the leach liquors by precipitation on detinned scrap iron . Leaching the calcareous ore for approximately 10 days recovered 62 percent of the total copper . The sulfuric acid consumption was 9.6 pounds per pound of copper recovered . Treatment of the siliceous ore recovered 62.5 percent of the total copper in a 2.5 - day leach and the acid consumption was 3.7 pounds per pound of copper recovered . Cement copper products that assayed over 71 percent copper were obtained from the leach solutions by precipitation on scrap iron . The bench - scale and continuous tests demonstrated that downward percolation leaching of the calcareous ores was technically feasible but not economically practicable because of high acid consumption by the gangue . Leaching of the siliceous ore was rapid and the acid and water requirements were nominal . The downward percolation leach procedure is simple and requires a minimum of plant equipment .

Jul 1, 1960

By C. H. Johnson

This paper on the out-and-fill method of mining is one of a series on mining methods published by the United States Bureau of Mines. It has been compiled chiefly from recent publications of the bureau describing in detail mining methods and costs at various mines. Other sources of information were the technical press, the Transactions of the American Institute of Mining and Metallurgical Engineers, the Mines Haudbook, and company reports. References other than those mentioned in Table 1, which lists the mines entering into this discussion and gives general data regarding them, are given in the body of the paper. The authors wish to acknowledge the kind assistance of many operating officials, either through correspondence or in the course of numerous visits to their mines. DEFINITION OF CUT-AND-FILL STOPING The out-and-fill method of stoping is that method in which relatively small sections or slices are taken successively from the lower surface of a block of ground by open-stoping methods, the broken ore being removed and each section filled with waste material before the next is mined. This definition excludes shrinkage stoping, even with subsequent filling; it excludes square-set and fill methods; it excludes the Mitchell slice method, which may be classed as underhand square-setting; it excludes the systematic use of stull sets and filling, which is a variation of square-setting; it excludes any method involving the caving of the ore, walls, or overburden during the process of extraction, although caving may be allowed to take place when the waste fill is withdrawn for use in other stopes; and it excludes any open-stope method without filling. Through variations, which will be discussed later, the cut-and-fill method merges into shrinkage stoping, open stoping, or square-setting. The use of casual timber support, such as props, stulls, or timber cribs for holding up weak portions of the back does not constitute a change from cut-and-fill to square-set mining.

Jan 1, 1933

By SUMNER S. SMITH

Mine inspection in Alaska by the Federal mine inspector was somewhat handicapped during 1915,the inspector having to spend a large part of the summer and fall in examining the Matanuska coal field in connection with the designation of the Government reservations and the leasing units in that field. However, in addition to>this work, the mines in southeastern and southwestern Alaska were inspected by both Federal and Territorial inspectors, a considerable number of men near the Federal inspector's officeat Juneau were trained in first aid to the injured and in the use of mine rescue apparatus, the mines of the interior and of Seward Peninsula were inspected by the Territorial inspector, and a suit was brought in the name of the Territorial inspector for the nonreporting of serious accidents under the Territorial inspection law. The work of the Federal inspector was handicapped also by a lack of field assistants. This condition is likely to be serious, as preparations have been made for opening the Matanuska, Bering River, and Nenana coal fields, and a number of permits granting the free use of 10-acre tracts in other fields throughout the Territory have been issued. The need of a comprehensive inspection law and experienced engineers to safeguard the opening of coal mines by operators who are not familiar with coal mining and are using inexperienced help is obvious.

Jan 1, 1917

The selective placement of coal strip mine overburden is examined. Physical end chemical properties of spoil detrimental to revegetation and groundwater are detailed. The United States is divided into regions of similar problems. Five mining methods already used in the industry, that are capable of selectively handling; waste are examined in detail. Technical and economic comparisons are made for the systems when applied to realistic mine settings. The same analysis is conducted for five novel methods capable of selectively handling waste. Comparisons arc made between novel and existing methods. Suggestions for new and modified equipment are outlined. Recommendations for further research are provided.

Jan 1, 1981

The Bureau of Mines is responsible for a broad spectrum of programs for meeting the diverse and changing mineral resource needs of the Nation. These programs are managed by the Director and two Deputy Directors, who formulate general policy and program direction from the Washington, D.C., headquarters. A senior advisory staff, consisting of the Chief Staff Officer, Chief Scientist, and Chief Mining Engineer, provides advice and consultation to the Director on a wide range of scientific and technical matters and acts on behalf of the Director to maintain liaisons with other government agencies, mineral industries, and professional societies. Bureau program activities are classified into two major functions: (1) Developing new and improved technology that will make the production and processing of minerals more efficient, safer and more healthful for mineral workers and the public, and more compatible with a quality environment.

Jan 1, 1979

By A. Monomakhoff

If a conductor traversed by an electric current is broken, a conduction forms in the air between the two broken ends of the wire. This conduction manifests itself in an initial phase by an electric spark and, in a second phase, by an arc if the the circuit continues to supply sufficient power. This arc goes out when the distance between the two ends of the conductor becomes sufficiently large. If the break occurs in an explosive atmosphere, the energy contributed by the arc can cause an explosion. To avoid such accidents, electric circuits that may be utilized in hazardous atmospheres can be made "intrinsically safe". The investigation which we conducted is part of a research project on the intrinsic safety of arcs of high intensity but short duration, in the case of resistive circuits. We developed an electronic system which makes it possible to limit the duration of an arc at the level of the break of a conductor traversed by a current with a possible maximum intensity of 80 amperes. This experimental device for monitoring and measuring the parameters of the arc has shown that arcs of high intensity but with a duration limited to a few microseconds do not ignite an explosive methane-air mixture.

Jan 1, 1975

By Richard D. Miller

The helium resources base of the United States was estimated by the Bureau of Mines to be 1,070 Bcf as of January 1, 1985. These resources are divided into four categories in decreasing degree of assurance of their existence: (1) helium in storage and in proved natural gas reserves, 280 Bcf, (2) helium in probable natural gas resources, estimated at 243 Bcf, (3) helium in possible natural gas resources, estimated to be 287 Bcf, and (4) helium in speculative natural gas resources, which makes up the remaining 260 Bcf. These helium resources are further divided into depleting, non-depleting, and stored classifications. The depleting resources are those associated with natural gasfields that are, or will be, produced for the natural gas they contain. Almost all of the helium in potential (probable, possible, and speculative) natural gas resources is included in this classification. These depleting resources are estimated to contain 900 Bcf of the total helium resource base. Helium resources contained in nondepleting natural gas resources, those in shut-in, abandoned, or otherwise nonproducing natural gasfields, are estimated to total 133 Bcf. There is 37 Bcf of helium in storage in the Federal Government-owned Cliffside Gas Field near Amarillo, TX.

Jan 1, 1987

By R. W. Fatzinger

The accident-frequency rate for placer mining in 1942 is reported as 36.923 accidents per million man-hours worked. This figure places placer-mining accident frequency slightly higher than that given for quarrying-35.7-but considerably under the 78.0 for coal mining and 56.5 for metal mining.4 Placer mining is subdivided into four types of activity: Underground, surface, dredging, and hydraulicking. It is the purpose of this paper to present and discuss safety practices in dredging and hydraulic mining; therefore, the following considerations will be limited to these two types of placer mining.

Jan 1, 1948

By BUREAU OF MINES

This report is submitted in accordance with the provisions of the Synthetic Liquid Fuels Act of April 5, 1944 (30 U.S.C. 321-325, as amended), which require that: "The Secretary of the Interior shall render to Congress on or before the first day of January of each year a report on all operations under this Act." Owing to the broad scope of the content and the diversity of interests represented, the Annual Report for 1953 has been divided into two separate publications. Each has been published by the Bureau of Mines as a Report of Investigations, and the respective titles follow: R. I. 5043, Part I - Oil From Coal. R. I. 5044, Part II - Oil From Oil Shale. Identical in each report, the introduction summarizes research progress made in 1953 under the entire Synthetic Liquid Fuels program. A free copy of each of these publications may be obtained by a written request to the Bureau of Mines, Publications Distribution Section, 4800 Forbes Street, Pittsburgh 13, Pa. The R. I. number and title of the publication desired should be indicated.

Apr 1, 1954

By V. L. Burdick

A literature review of current uses of Mn02 in ceramic applications with suggestions for future research. Historical background, oceanographic distribution, geology, exploitation, law and politics. Uses of Mn02 in ferrites, semiconductors, catalytic processes, thermo-luminescence and photochromic materials. Select bibliography of 33 items, plus 129 references.

Jan 1, 1980

This report summarizes the cost of U.S, mining and milling industry compliance with the Environmental Protection Agency (EPA) interim water quality guidelines for waste discharges. Applicable excerpts from Public Law 92-500 are stated and interpreted in conjunction with the guidelines being used for implementation of the law. Over 200 U.S. Army Corps of Engineers applications for discharge permits were used to develop the quality and quantity data base needed to estimate the cost to comply with EPA guidelines, Cost of three basic treatment methods were considered: Aeration, addition of lime, and sedimentation. From the process design, cost-capacity graphs were developed to consider maximum flow rate, maxi lime addition, and average flow rates. The graphical method used in this evaluation should provide a reasonable guide to the effect of waste treatment and, therefore, Public Law 92-500 and corresponding EPA guidelines on the mineral processing industry. The cost of complying with the EPA guidelines will have the effect of prompting the mining industry to minimize the production of waste water and of undertaking some additional treatment, Two case studies are presented to illustrate efforts that might be fruitful for minimizing waste water production and for treatment of combinations of acid mine drainage, mill wastes, and metallurgical process wastes when treatment is deemed necessary.

Jan 1, 1975

By Bruce McDonald

This report contains the findings of a study to perform a task and skill analysis of roof-bolting operations, with respect to the operational training requirements and to prepare detailed recommendations for the operational training system. The extent of the problem was determined by visiting underground coal mines, interviewing training and safety personnel, observing and interviewing roof-bolter operators, and reviewing present training programs and facilities. In conjunction with the mine visits an extensive literature search was conducted with emphasis on training, mine safety, and accidents involving the roof-bolting operation and roof-bolter operators. A number of training programs and training devices were considered resulting in the development of a recommended training program including training devices to be used and establishing training objectives.

Jan 1, 1977

By F. E. Armstrong

This Bureau of Mines publication reviews 237 papery on radiometric prospecting, which is the measurement of naturally occurring radioactivity in the earth's surface and its application to petroleum and natural gas exploration. Many theories and documented surveys are listed in both support and refutation of this reported phenomenon, and the Bureau of Mines is conducting research to obtain direct field information in order to determine the statistical credibility of a radiometric method of predicting petroleum accumulation.

Jan 1, 1973

By S. Vennos

As a result of Synopsis 73-16 Dynadyne responded with an unsolicited proposal offering the Bureau of Mines to develop an ultra-low volume coal mine dust personal sampler. In the ensuing technical discussions the choice of a desirable volumetric rate became a focal point. While, the initial proposal was based on a volumetric rate in the area of 50 cc/min the Government expressed interest in a variety of mass flow rates ranging from 50 cc/min to 2000 cc/min. The physical characteristics such as weight, volume and configuration of a personal sampler are to a large extent - dependent on the operating volumetric rate. It became readily apparent that the optimum size of such an instrument as a function of volumetric rate was not known and that a study of the choice of optima was essential prior to beginning the development, Hence, the Government authorized a two phase approach to this project. Phase I was to include a Technical Evaluation Study of optimum characteristics in the range between 0. 1 to 2. 0 lpm. Based on these findings and in consultation with MESA personnel, the Bureau of Mines was to authorize the second phase that is, the development. Phase II, was to include the drawing of a set of performance specifications stating among others the desired operating volumetric rate. In this report, every effort was made not only to present the actual work done over the course of this development, but to reflect also our engineering "thinking" providing answers as to the "why" we preferred certain solutions over others. We believe that this added dimension is not only useful for the Government official evaluating this report, but also that the Government is entitled to it providing the official with an educational content useful in avoiding future costly repetitions of similar situations.

Jan 1, 1975

By Lindsay D. Norman

Eleven major pyrometallurgical processes and operations suggested for recovering manganese from domestic resources are described. These include seven pyrometallurgical processes that usually yield a ferroalloy or a product from which ferromanganese can be produced in one operation. The remaining four involve pyrometallurgical operations whose products require either an additional two-stage process to produce ferromanganese or chemical processing to recover a high-quality manganese oxide product.

Jan 1, 1962

By W. L. Zeigler

This paper describing the milling practice of the Hecla Mining Co. is one of a series being prepared by the United States Bureau of Mines. The concentrator of the Hecla Mining Co., which utilizes combined gravity and flotation methods, is located at Gem, Shoshone County, Idaho, about 2 miles south of the Hecla mine at Burke. It has a maximum capacity of 900 tons per day and all ore treated is drawn from the company's Hecla mine. Milling ore for 1910 contained 9.7 per cent of lead, 1.2 per cent of zinc, and 4.77 ounces of silver per ton.

Jan 1, 1932