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By Charles L. Kimbell

In broadest overview, a substantial part of the world's mineral industry in 1990 registered small gains over its 1989 performance, but traditional statistical measures of mineral industry performance, namely global production, trade, and consumption levels, failed to mirror these gains. This was because of the sharp downturns in the mineral industry activity in the U.S.S.R. and the former centrally planned economy nations of eastern Europe. These downturns in this one geographic area had influences on almost all traditional statistical series, in some cases simply significantly reducing growth, in other cases providing for a global downturn, in almost all cases despite considerably brighter outlooks based on activities in other world areas. To be sure, the U.S.S.R. and eastern Europe were not the only places on the planet suffering problems of one type or another in 1990 that impacted on minerals industry activity, but with the acquisition of information presently available, it seemed almost assured that the difficulties of these economies in transition will be the most difficult of problems to resolve in the long run. It certainly appeared that the legacy of the half century or more of economic central planning will be a decade or more of very difficult adjustments, and a number of these will greatly affect not only the minerals industry of these transition countries, but also the rest of the globe's mineral industry as well.

Jan 1, 1993

By Fred N. Kissell

The U.S. Bureau of Mines was established in1910 to reduce .the high accident rate in the nation's coalmines. For 85 years, it conducted a wide variety of tasks related to mining before it was abolished in 1995. The BOM had many technology transfer successes in its lifetime, including more than a dozen "R&D100" awards. This essay identifies and discusses five "transfer factors" that can explain the success (or failure) of many Bureau of Mines projects. These five factors are termed "pressure, pitfalls, path, price, and profit."

By G. H. Hopkins

Like most industries, the refining industry has in recent years been confronted with the problem of a decreased martin of profit, due both to a general lowering of prices and to rising costs. This has resulted in accelerating a program of increased efficiency an evidenced by improved methods and the installation of equipment designed to affect a number of economies hitherto regarded as unimportant. Perhaps the most important of these has been that of fuel economy for, as is not often realized, a refinery consumes about one-tenth as much fuel as it produces. A recently completed canvas., made by the Bureau of Mines for the purpose of determining the trend of fuel consumption at refineries in the United States, showed the following outstanding points, (1) a decrease in the use of oil for fuel in 1926 of approximately 4,000,000 barrels as compared with 1925; (2) a small decrease in the use of coal; (3) a material increase in the use of gas, both natural gas and refinery gas; and (4) a considerable increase in the use of petroleum coke.

Jan 1, 1927

By J. S. Browning

The Bureau of Mines investigated the concentration characteristics of high-clay sylvinite ores from potash companies operating in the Permian basin near Carlsbad, N. Mex. These ores, containing 14 to 19 percent K20 and 3 to 5 percent clay slimes, cannot be effectively processed by current commercial flotation methods because of their high clay content. A solution to this problem was shown to be the use of two-stage moderate scrubbing conditions for clay disaggregation and removal as opposed to strenuous attritioning. Bench-scale beneficiation techniques for recovering potash minerals by flotation from the scrubbed material resulted in acceptable product grades and recoveries. By using a coarse grind, emphasis was placed on production of premium granular and coarse products. Flotation results showed that concentrates of 59.6 to 60.4 percent K.0 values can be obtained. Continuous pilot plant beneficiation techniques for recovering potash minerals by flotation resulted in concentrates containing 58.8 to 59.8 percent K20 with recoveries of 69.7 to 81.4 percent of the K20.

Jan 1, 1975

To improve efficiency in producing clarified water from mineral and metallurgical processing streams containing suspended particles. Approach Particles suspended in mineral and metallurgical processing streams are filtered out by granular magnesium oxide (MgO) used as the medium in deep bed filters. How It Works MgO is substituted for the silica sand or garnet sand currently used in conventional deep bed filters. These filters presently consist of a 24- to-48-inch-deep layer of either silica sand or mixed media, consisting of a stratified combination of anthracite coal, silica sand, and garnet sand. As waste water containing fine solids is percolated through the granular bed, the suspended particles become attached to the filter grains. When MgO replaces sand as a filter medium, the overall filter capacity is generally increased 50 to 80 percent, and no equipment modifications are necessary for filter operation. MgO is unique because it has a positive surface charge in water while most suspended materials are negative. The attraction of these negatively charged suspended particles to MgO enhances filtering performance. As is necessary for all good media, MgO is insoluble and nontoxic.

Jan 1, 1983

By F. J. Bailey

"In the fall of 1919, the U.S. Bureau of Mines began an inquiry as to the possibility of utilizing airplanes in conjunction with its rescue work, for quickly transporting engineers and oxygen rescue-apparatus to mine disasters.It was realised that this proposed use of airplanes has serious limitations, and if it were feasible, that the Bureau would have to rely on the cooperation of the established aviation fields of the U. S. Air Service for furnishing airplane service. Therefore Van. H. Manning, Director of the Bureau of Mines, under date of October 28, 1919, wrote the Director of Air Service outlining the rescue and first aid organization of the Bureau, the location of headquarters of district engineers, the distribution of safety cars and stations, and other essential details, and asking whether the Air Service could cooperate with the Bureau in the event of serious mine disasters. Major-General Charles T. Menoher, Director of Air Service, responded that the Air Service would be glad to cooperate insofar as possible, and designated those Air Service stations nearest the district engineers' headquarters, which might be best able to assist.The Bureau of Mines has ten mine rescue cars and eight mine safety stations distributed throughout the mining regions of the United States. The cars are each equipped with sets of oxygen mine-rescue breathing-apparatus and first-aid supplies. The car personnel consists of a mining engineer, surgeon, foreman, first-aid miner, clerk and cook. A foreman miner is in charge of each station and at five of the eight stations are mine safety trucks. The work of the cars and stations is two-fold; (1) Assisting in rescue and recovery work at mine disasters, and (2) training miners in mine rescue and first-aid methods, and in investigations looking to prevention of mine accidents. The country is divided into nine safety districts, with nine district engineers in charge."

Apr 1, 1920

By A. J. Barry

[This is the third report related to fundamental retail roof-bolting research in underground mines (1, 2)3/ and describes an investigation of the torque-load relationship for 3/ -inch, expansion-type mine roof bolts. In a previous investigation the relationship between torque and bolt load was established for 1-inch slotted-type bolts (1). The two types of bolts differ in diameter and method of tightening and consequently may exhibit different torque-load behavior. The 1-inch bolt is tightened by turning the nut, the 3/4-inch bolt by rotating the beaded bolt itself. Experience indicates that roof bolts should be tightened to moors satisfactory anchorage sand to minimise nag of tie roof over the mine opening. The generally accepted means for determining the bolt load is to see a torque wrench to measure he torque applied in tightening the bolt and, from a predetermined relationship between torque and molt load, to, determine the corresponding bolt load. Because frictional effects may vary between one type of shell assembly or bolt and others, 7 types of expansion shell units and 3 types of 3/4-inch-diameter, mild steel bolts were tested.]

Jan 1, 1954

By William H. Pomroy, Shail J. Butani

"This Bureau of Mines publication presents a statistical analysis of official U.S. Mine Safety and Health Administration (MSHA) metal and nonmetal mine fire reports from 1950 through 1984, plus accounts of selected nonreportable fires (less than 30 min and no injury) and opinion data on fire hazards from mine safety directors. Fires were analyzed by time trends, ore type, ignition source, burning substance, location in mine, equipment involved, means of detection, duration, number of injuries and fatalities, mining method, and successful extinguishing agent. The leading ignition sources were electricity in underground fires and engine heat in reported surface fires. The most frequent burning substance was combustible liquids for all nonreportable fires, reported surface fires, and reported underground fires from 1978 to 1984. For underground fires reported prior to 1978, timber was the leading burning substance. Mobile equipment was the type most frequently involved in both underground and surface fires. Underground fires occurred most often in haulageway or drift areas, and reported surface fires occurred most often in plant and mill buildings, while most nonreportable surface fires occurred in other areas. The most common methods of extinguishment were water hose lines for reported fires and dry chemical handportable extinguishers for nonreportable fires. INTRODUCTIONIn support of the Bureau of Mines research on mine fire protection, two separate baseline studies on mine fire incidents have been prepared. The first study addressed coal mine fires. The results of that study are summarized in the Bureau's Information Circular 8830, ""A Statistical Analysis of Coal Mine Fire Incidents in the United States From 1950 to 1977."" This second report, addressing metal and nonmetal mine fires, is the companion to IC 8830. Together, these two reports provide a comprehensive, factual summary of the mining industry's fire experience.This report, like IC 8830, covers (1) MSHA fire incident reports, (2) records of nonreportable fires (less than 30 min and no injury), and (3) mine safety directors' opinions on fire hazards. The MSHA fire reports provide the most reliable, objective, and accurate historcial record of the major noncoal mine fires that occurred during the study period (1950 through 1984). However, MSHA fire reports alone understate the true magnitude of the fire problem because metal and nonmetal mines have been legally required to report fires to MSHA only since 1968. Although some fires were reported prior to 1968, doubtless a great many were not. Also, the reporting regulations that took effect in 1968 specify that only fires lasting 30 min or longer or involving an injury need to be reported. MSHA fire reports are thus limited in scope by MSHA's legal authority. In order to provide a more comprehensive data base, it was also necessary to gather and analyze mine company records of nonreportable fires."

Jan 1, 1986

By R. V. Lundquist

The work described in this report, part of the Bureau of Mines long-range program to develop methods of utilizing submarginal domestic sources of aluminum, was undertaken to investigate the effects of iron in the lime soda sinter process, The approximate Fe2O3 content in a sinter for maximum alumina and soda recovery was 8 to 9 percent. Fe2O3 appears to inhibit gelation, and 15.5 percent Fe2O3 produces effects similar to those produced by 1 percent sucrose. In the lime soda sinter process, aluminum silicates are sintered with limestone and soda ash to yield dicalcium silicate and sodium aluminate. The sodium aluminate is extracted by leaching in caustic solution. The solution is purified by heating in an autoclave with lime to remove silica, and alumina trihydrate is precipitated with carbon dioxide. The reactions involved in sintering and leaching are complex. A number of studies by the Bureau of Mines4-9 and others1 indicate that the iron content of sinters influenced the recovery of alumina and soda and the gelation characteristics.

Jan 1, 1962

By John A. Richards

This paper is one of a series being published by the Bureau of Mines on mining methods and costs. It describes briefly the manner in which slusher hoists and scrapers are used in connection with clock-caving methods at the Emma Nevada mine of the Consolidated Coppermines Corporation, Kimberly, Nev. Kimberly is in the Robinson mining district, White Pine County, 7 miles west of Ely. The district is served by the Nevada Northern -Railroad, which branches from the main line of the Southern Pacific at Wells, Nev., 140 miles north, Paved U. S. Highway 50 from Salt Lake City, Utah, to Reno, Nev., passes through Ely. The altitude at the collar of the Emma Nevada shaft is 7117 feet. The surrounding hills are covered with a sparse growth of juniper, pinon, and mountain mahogany.

Jan 1, 1940

By H. Kenworthy

The investigations described in this report were undertaken to demonstrate, on a laboratory scale, the possibility of recovering several million pounds of tin plus tungsten contained in stockpiled and currently rejected slags from the Longhorn tin smelter at Texas City, Tex. At the same time, it was anticipated that the treatment procedures developed might be applicable to slags from other tin-smelting operations. Results of the laboratory work show that it is possible, by pyrometallurgical means, to separate the tin and tungsten into products of intermediate grade that may be returned to the smelter circuits for further upgrading. Several methods of treatment were investigated. The methods that proved effective were: Fusion reduction, chloride volatilization, sulfide volatilization, and carbide formation. Over 90 percent of the tin and tungsten could be removed from the slat by any of these methods. Each type of treatment has advantages and disadvantages, and it could not be determined from the small-scale work which method was the more meritorious. Tungsten and (in some types of treatment) tin-bearing products were diluted by iron, the separation of which will require additional studies. Prevention of a portion of the iron from reporting with the tin or tungsten is a distinct advantage and possibility that will require inure laboratory work to develop the needed techniques for its accomplishment. Tin products from single treatments of stag ranged up to 75 percent in tin content but were more generally under 35 percent. Tungsten products were usually under 15 percent; but segregated portions could be selected, at a sacrifice in recovery, that contained up to 50 percent tungstic oxide equivalent.

Jan 1, 1957

By George E. Fasching

The Bureau of Mines has developed a pulse counting system with improved energy resolution and having dual channels to process pulses at different rates and a pulse pileup detector for channel selection. Pulse input is delayed until the detector determines if any pulse is so closely followed by a second pulse as to constitute pulse pileup. If no pulse pileup is detected, the slower channel is selected; this clips the pulse to a wide pulse width to retain good energy resolution. If pulse pileup is predicted, the fast channel, with correspondingly shorter pulse width, is selected to improve resolution with respect to time. Output of the two channels is transmitted to a pulse height analyzer for interpretation. The pulse processing system can process count rates above 300,000 counts per second with little loss in energy resolution.

Jan 1, 1974

By F. S. Crawford

The average visitor to a large electric-shovel operation may wonder how electric power can be treated as carelessly as apparently it is in open-pit mining, and how the mining company can string it carelessly along the ground in great, black, hoselike cables, whereas the power company, which has learned to respect his deadly agency, keeps power lines far out of reach. This is explained by the fact that this particular kind of application of power to moving machinery requires the use of trailing cable instead of the more permanent type of construction that permits a moving contact, such as a trolley. The cables are designed to insulate fully the enclosed power lines against damage and loss of current; and employees are taught to handle them carefully, although engineers are not satisfied that the trailing cable is foolproof and are seeking constantly to improve methods and equipment to insure greater safety. In some sections they rely mainly on the construction of the cable and perfection of equipment, while in others additional precautions are taken, such as handling the cable with rubber gloves, slings, tongs, or loops. In some sections no temporary repairs are made to cables, while in others such repairs are made and later are vulcanized in the shop. At some operations the cycle of shovel duties is arranged so that cables are very seldom exposed to flying rock fragments while at others this exposure appears to be unavoidable. Methods of fastening the cable to the shovel frame and transporting the loose cable vary. Inspection and care of the cable are important in insuring its safety and durability. A limited amount of information was obtained by field engineers of the United States Bureau of lines from operators in various parts of the United States, as methods of handling electric-shovel operations differ with the districts; practices followed and equipment used in these districts are described in this circular.

Jan 1, 1936

By D. Harrington

Advocates of health and safety in mining have found themselves confronted in recent years with what might appear to be contradictory procedures with regard to dust occurrence in mines and what appear to be suitable methods or measures to give the mines and mine workers a maximum measure of protection against dust. A concerted and relatively effective drive has been made to introduce rock dust into bituminous and lignitic coal mines to prevent or limit explosion and fire disasters, while an equally determined effort has been and is now being made to curb rock dust or to eliminate it from air in metal mines to prevent or at least limit the occurrence of miners' consumption and other diseases. Both procedures are logical even though the efforts appear to be of an opposing nature. While rock dusting has not been applied in coal mines nearly as universally or as effectively as could and should be done, nevertheless a careful analysis of the record of the past 10 years indicates that the amount of rock dusting that has been done has resulted in the saving of a minimum? of 200 lives annually certainly no small achievement. Largely but by no means wholly due to the use of rock dusting, the number of fatalities from explosions and fires in our coal mines in the last 4 years haw been reduced more than 75 percent as compared with the 4-year period 1911-15, the first years of the existence of the United States Bureau of Mines, which was brought into existence in 1910 largely to try to do something about reducing the disgracefully high fatality occurrence from explosion disasters in our coal mines. Hence, rock dusting has been given at least a. trial and has proved its effectiveness definitely.

Jan 1, 1937

By H. R. Grau

NIOSH’s Pittsburgh Research Laboratory is currently involved in research to identify silica dust generation in underground metal/nonmetal mines. The ultimate goal of this research is to develop control technologies to reduce worker exposure to respirable silica dust. Commodities and job classifications with the highest silica dust exposure have been identified through analysis of the Mine Safety and Health Administration (MSHA) compliance dust sampling database. Dust surveys were conducted in an underground limestone and gold mine to investigate silica dust sources, generation levels, and controls being used. A summary of the mining operations, sampling procedures, resulting data, and suggested methods to improve the dust control will be provided.

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

MINE VENTILATION NETWORK ANALYSIS

Jan 1, 1977

By Gerrit V. R. Goodman, Charles D. Taylor, Edward D. Thimons

Future coal mining systems will be able to cut from crosscut to crosscut where advances could exceed 100 ft. However, limitations arise when ventilating such mining systems. In deep advance mining, there would be no workers at the face to advance ventilation tubing or curtain manually. Traditional methods also provide no means for maintaining face ventilation after the miner backs away from the face. U.S. Bureau of Mines research is studying means to provide effective ventilation at cut depths beyond the current limit of 40 ft. Several innovative ventilation schemes are currently being considered. One such method is the use of a jet fan to ventilate a deep cut. A jet fan is simply a freestanding fan using little or no ducting to direct the ventilation flow. Jet fan testing in a 90-ft entry revealed that higher exit velocities and greater penetration depth occurred when various configurations were used to confine and direct the air flow. Additional testing also indicated that 2,200 cfm of fresh air was delivered to the face 90 ft distant when a check curtain was used to limit entrainment around the fan. Without this curtain, this quantity dropped to only 1,000 cfm This testing indicated that a jet fan was capable of providing ventilation to a distant face area. It also highlighted potential problems, such as recirculation at the fan and reentrainment in the jet flow. Despite these potential problems, jet fans may be adequate for ventilating cuts exceeding 40 ft.

Jan 1, 1992

By A. A. Campoli

Retreat pillar mining concentrates stresses on workings directly outby gob areas, which can result in coal mine bumps. The development of bump-control design criteria by the U.S. Bureau of Mines was furthered by data from a novel bump control mining method at the Olga Mine, McDowell County, WY. The pillar splitting, retreat mining system induced large pillar pressure increases and roof-to-floor con-vergence. Roof-to-floor convergence monitoring proved to be a valuable tool in evaluating the pillar splitting mining method and localized destressing techniques. Maximum strain energy storage in chain pillars appears to have occurred just prior to the first of four split cuts. At that point a 15-ft-wide, highly fractured perimeter confined the core of the 55-by 70-ft pillars, permitting the pillar core to support tremendous pressures. Splitting the chain pillars into two 17.5-by 70-ft wings removed the confinement load, resulting in pillar yield. Thus, the pillar splitting mining method successfully redistributed the weight of the roof away from the pillar line. Shot fire and auger drilling destressing techniques aug-mented the pillar splitting mining method by redistributing the weight of the roof.

Jan 1, 1989

By J. R. Allsup

In cooperation with the Division of Advanced Automotive Power Systems Development, Environmental Protection Agency, the Bureau of Mines studied a conventional spark-ignition engine as a prime mover for use in a hybrid system. The study involved both steady-state and transient engine operation with ignition timing, air-fuel ratio, exhaust gas recirculation, oxidizing type catalytic converters, engine speed, and power output as variables. Data were obtained from two 1971 model 350-cubic-inch-displacement engines mounted on engine dynamometer stands. When the hybrid engine was operated with an oxidizing catalyst at power output levels required for a 4,000-lb curb weight hybrid vehicle, carbon monoxide and hydrocarbon emissions could be reduced to approximately 2.0 grams and 0.3 gram per brake horsepower-hour, respectively. With exhaust gas recirculation, oxides of nitrogen emission levels could be reduced to approximately 1.2 grams per brake horsepower-hour.

Jan 1, 1974

Provide d comprehensive source of up-to-date information about technology for revegetating coal mined lands. Approach A great deal of activity and research in the field of coal mine revegetation has been reported in technical literature, both before and after the passage of Public Law 95-87, the Surface Mining Control and Ruclamation Act of 1977 (SMCRA). This information is widely scattered throughout books, scientific journals, periodicals, Government reports, and other sources, and there has been a need to develop a method of accessing it quickly and efficiently. At the request of the Office of Surface Mining Reclamation and Enforcement which promulgates and enforces regulations implementing the act, the Bureau of Mines has prepared a document that identifies literature relevant to coal mine revegetation. Most of the literature available on this subject has been published during the past 15 years. To tap this reservoir of information, 14 data bases were accessed from DIALOG SDI (Selective Dissemination of Information) Service using three keyword combinations (surface mining and reclamation, strip mining and reclamation, and revegetation). This procedure generated over 7,000 listings. The U.S. Department of Energy's ENERGY data base was selected from the 14 DIALOG bases, both for its large number of listings and for its broad coverage of literature. This data base contains all the unclassified information that passes through the Technical Information Center of the Department of Energy, including reports, journal articles, conferences, patents, books, monographs, theses, and engineering materials relating to energy development.

Jan 1, 1986