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By Arthur Metcalfe, Edward Thomas, A. J. Barry

"Early in 1947 the Bureau of Mines became interested in adapting suspension roof support to coal mining 5/ as a possible means of reducing the high rate of accidents from falls of roof. For a time the program made little progress be¬cause of the shortage of steel products after the end of World War II, but during the past 8 months this restriction has eased, and as of May 1, 1949, 114 mines had either started experimental work or had ordered materials and equip¬ment in anticipation of trial installations. It is estimated that 30 linear miles of roof in underground passageways have been secured by this method in recent months, and no lost-time roof-fall accident has been reported in these areas up to that date.Many coal-mining companies in widely separated localities have cooperated in making experimental installations. In very few instances are these companies entirely satisfied that they have arrived at the best solution in determining the most efficient adaptation to suit their particular conditions. Moreover, new ideas and modifications of the basic principle are constantly being brought to light and are being tested. Available test data is far from complete, and it is conceivable that some new idea will be developed to alter the present concept of proper technique; therefore, this progress report does not attempt to answer all questions that might arise in connection with this method of roof support; it simply recounts the experience acquired to date. Consequently, few references to costs are made. Up-to-date quotations on material and equipment used in suspension roof-support installations may be obtained from numerous mine-supply companies.The authors gratefully acknowledge the cooperation of mining companies whose personnel made possible collection of the information contained in this circular: Bethlehem Collieries Corp., Barrackville, W. Va.; Berwind-White Coal Mining Co., Windber, Pa.; Consolidation Coal Co., (Ky.); Jenkins, Ky.; Consolidation Coal Co. (W. Va.), Fairmont, W.Va.; Clinchfield Coal Corp., Dante, Va.; Consolidated Coal Co., St. Louis, Mo.; Hanna Coal Co., St. Clairsville, Ohio; Missouri Portland Cement Co., Sugar Creek, Mo.; Pocahontas Fuel Corp., Pocahontas, Va.; Reppert Coal Co., Dola, W. Va.; St. Joseph Lead Co., Bonne Terre, Mo.; and Tennessee Coal, Iron, & Railroad Co., Birmingham, Ala.The fundamental theory of suspension roof supports is not new; in fact, its application in the construction of beams predates mining itself. The basic principle involved is the reinforcement of roof rock with steel rods inserted in the roof and anchored therein at points where the rock is least likely to be affected by stresses resulting from mining. Such roof supports have been used in mines for many years in widely separated localities. The St. Joseph Lead Co., operating in southeastern Missouri, apparently was the first large mining company to prove the practicability of the principle by applying it in a systematic manner for securing roof for more than 20 years (fig. 1)."

Sep 1, 1949

By A. W. Henderson

This investigation was performed to develop chlorination methods for extracting tungsten from scheelite and from an ore concentrate containing a mixture of scheelite and wolframite. On a laboratory scale with proper temperature control using elemental chlorine, over 90 percent extraction of tungsten is achieved. Carbon and sulfur dioxide were studied as reducing agents. The effects of salts such as calcium fluoride and sodium chloride were studied as additives to increase extraction and to reduce impurities in the volatile tungsten chloride product. Sodium chloride reacts with ferric chloride to form a nonvolatile double salt; whereas the chlorides and oxychlorides of tungsten are volatile and consequently condense free of iron. Separation of tungsten from molybdenum from an equal molar mixture was successful by fractionally distilling the oxygen-free chlorides and by selectively condensing the oxychlorides. Yields of 60 and 80 percent, respectively, were achieved for separating the less volatile tungsten chlorides containing less than 0.5 percent molybdenum.

Jan 1, 1965

By G. R. Strimbeck

The Federal Bureau of Mines has been developing processes for producing synthesis gas directly from coal, oxygen, and superheated steam. An atmospheric-pressure pilot plant was constructed and operated to: 1. Determine the operability of the plant for gasifying coals of different ranks under various operating conditions. Listed in decreasing order of rank, these coals included a Pennsylvania anthracite, a bituminous A coal from the Sewickley bed, West Virginia, and a subbituminous C coal mined in the Lake de Smet region of Wyoming. 2. Determine the effect of varying operating conditions on: (a) Standard cubic feet (std.c.f.) of oxygen and pounds of coal of different rank required to make M std.c.f. of product gas (carbon monoxide plus hydrogen); (b) carbon gasified, percent; (c) exit-gas temperature, degrees F.; and (d) heat loss, B.t.u. per pound coal. 3. Compare the gasification characteristics, indicated in item 2, of coals of different rank: Bituminous A, anthracite, and subbiturninous C. 4. Determine the concentration of dust in the gases produced and the efficiency of dust removal, and investigate the relation between the sulfur content in the coals gasified and the gases produced.

Jan 1, 1960

By Thomas J. Fisher, John J. Sammarco

This report (System Safety 2.1) is the second in a nine-part series of recommendations addressing the functional safety of processor-controlled mining equipment. It is part of a risk-based system safety process encompassing hardware, software, humans, and the operating environment for the equipment’s life cycle. Figure 1 shows a safety framework containing these recommendations. The reports in this series address the various life cycle stages of inception, design, approval and certification, commissioning, operation, maintenance, and decommissioning. These recommendations were developed as a joint project between the National Institute for Occupational Safety and Health and the Mine Safety and Health Administration. They are intended for use by mining companies, original equipment manufacturers, and aftermarket suppliers to these mining companies. Users of these reports are expected to consider the set in total during the design cycle. • 1.0 Safety Introduction.—This is an introductory report for the general mining industry. It provides basic system/software safety concepts, discusses the need for mining to address the functional safety of programmable electronics, and includes the benefits of implementing a system/software safety program. • 2.1 System Safety and 2.2 Software Safety.—These reports draw heavily from International Electrotechnical Commission (IEC) standard 61508 [IEC 1998a,b,c,d,e,f,g] and other recognized standards. The scope is “surface and underground safety mining systems employing embedded, networked, and nonnetworked programmable electronics.” System safety seeks to design safety into all phases of the entire system. Software is a subsystem; thus, software safety is a part of the system’s safety. • 3.0 Safety File.—This report contains the documentation that demonstrates the level of safety built into the system and identifies limitations for the system’s use and operation. In essence, it is a “proof of safety” that the system and its operation meet the appropriate level of safety for the intended application. It starts from the beginning of the design, is maintained during the full lifecycle of the system, and provides administrative support for the safety program of the full system.

Jan 4, 2001

By Robert E. Manning

The Federal Coal Mine Health and Safety Act of 1969 has placed stringent limitations on the noise levels in which employees may work. This act can result in both increased labor costs because of noise-exposure time limitations and in high capital costs for modification of present equipment, and the design of new equipment, to comply with the law. The development of new noise-control systems is thus of immediate interest to industry. A current Research program at U. S. Steel is aimed at developing methods of controlling both the exhaust-air noise and the mechanical noise of a Stoper drill, a pneumatic percussive tool used for roof-bolting purposes in coal mines which has an approximate air consumption of 100 cubic feet per minute. This program is being performed under a contract between USS Engineers and Consultants, Inc. and the Pittsburgh Mining and Safety Research Center of the U. S. Bureau of Mines. In previous work at U. S. Steel, kidney-shaped mufflers were designed that wrap around the air leg of the drill for control of the exhaust noise. These mufflers were designed with the aid of a digital computer program that predicts the acoustic performance of mufflers.

Jan 1, 1975

By Robert C. Dyni

This report details the investigation of multiple-seam longwall subsidence conducted by the U.S. Bureau of Mines from 1978 to 1989. A field investigation monitored ground surface movements over four upper-seam longwall panels and six lower-seam panels. The characteristics of the subsidence occurring as a result of mining these panels are examined; in particular, the angle of draw, subsidence development, total magnitude and areal extent, and critical width are evaluated and discussed. Comparisons are also made between the characteristics of multiple-seam longwall subsidence and single-seam longwall subsidence that occurred at the same site.

Jan 1, 1991

By Hendrik Gerritsen

The research to be described is directed to the construction of an instrument that detects methane in air. The principle on which it is based is that methane gas absorbs infrared radiation in the wavelength range of about 3.2 to 3.4 micron. Solid state p-n junctions of composition In, .97Ca.03As emitting radiation in a band centered at 3.3 micron were grown by liquid epitaxy on InAs. Fight separate growth cycles and a total of 200 diodes were measured to determine total power, wavelength peak, spectral. half width and reproducibility of the method. In order to compensate for temperature changes, dual emitter systems (one InGaAs, and one InAs diode) mounted on the same TO-5 header were made. These devices were imaged, using a folded optical path cell, on large area InAs detectors, grown by a planar diffusion technique. In the 0-50°C range the primary temperature sensitivity is in the InAs detector rather than in the emitters. Several methods to reduce the overall temperature sensitivity to within acceptable limits were demonstrated. Humidity was shown to have a negligible effect on the measurements.

Jan 1, 1976

By H. R. Babitzke

The purpose of this Bureau of Mine- investigation was to develop columbium and tantalum alloys suitable or u at elevated temperatures. Columbium and tantalum were combined with tungsten, hafnium, zirconium, molybdenum, vanadium, and titanium, and the resulting alloys were evaluated with respect to workability, hardness, electrical resistivity, strength at elevated temperatures, oxidation resistance, and weldability. Cb-33Hf-10W-10Ti, Cb-20111-5Mo, and Cb-30Hf-5Mo exhibited superior high temperature properties. Cb-33Hf-10W-10Ti had tensile strength values of 44,300 psi at 1,200° C and 16,500 psi at 1,400° C, Cb-20Hf-5Mo had values of 35,700 and 20,700 psi, respectively. The corresponding values for Cb-30Hf-5Mo were 38,900 and 17,800 psi. These alloys are fabricable by conventional methods with excellent strength at temperatures up to and including 1,400° C. An oxidation rate of 7 to 21 mg/cm2/hr was observed up to 1,000° C.

Jan 1, 1967

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Jan 1, 2011

By Curtis A. Jones

Continuing interest has been shown in developing processes for extracting nickel and cobalt from low-grade domestic deposits of these metals and in improving existing methods. Of special concern is the nickel-recovery installation at Nicaro, Oriente Province, Cuba, operated for the General Services Administration. The Bureau? of Mines felt that a bibliography would help familiarize personnel at various Bureau of Mines stations and General Services Administration contractors with extraction methods both in the United States and in foreign countries. When this task was under way it became apparent that to compile a complete bibliography would require considerable time, so it was decided to limit the first part to the later literature and issue it independently, thus making it available sooner. The present work supplements the first part and extends the coverage to the earliest years of nickel and cobalt metallurgy.

Jan 1, 1959

By R. A. Cattell

The Bureau of Mines recently observed its fortieth anniversary, and with the close of the fiscal year 1950 it completed 36 years of close cooperation with and helpfulness to the petroleum and natural-gas industries, whose technical problems it studies. Petroleum people likewise observed the ninetieth anniversary of the start of this truly American industry when "Colonel" Drake drilled the first well at Titusville, Pa., in 1859 (see fig. 1). Throughout the period, during which there have been many changes in the fuel and related economy of the country, this work has been carried on systematically by an organized entity of the Bureau first known as the Petroleum Division and in recent years as the Petroleum and Natural Gas Branch. Changes in the industries have been brought about partly by economic forces, partly by advances in technology, and in some measure by the impact of two world wars. As the needs of industry and the Nation have changed, so have the studies of the Bureau changed to meet these needs. Consistently, Bureau technologists and scientists have tried to keep in step with progressive movements; frequently, in fact, have taken the lead. Wherever possible, they have looked far ahead in their program of research, at the same time recognizing the needs of the hour.

Jan 1, 1951

By J. M. Mutmansky, S. Padmanabhan

"The subject of quartz occurrences in respirable coal mine dusts has been of increasing concern in recent years. The primary impetus for this concern has been provided by better measurement technology that has detected an increased number of mines with high quartz content in their respirable dusts. This paper presents the results of statistical analyses of quartz levels in multi-stage impactor samples from eighteen different coal mining sections located in Pennsylvania, West Virginia, Ohio, Illinois, Kentucky, Colorado and Ucah. The quartz and kaolinite determinations were then determined by combining impactor stage loadings to provide larger dust masses and applying the infrared spectrometry procedure outlined in Bureau of Mines/MSHA Method P7.The results will be presented using two categories of data collected during two separate phases of the research:(l) quartz concentration data from mines where quartz was known to be present in relatively high concentrations, and(2) quartz concentration data from mines chosen at random.The aspects of the occurrence of quartz in coal mine airborne dusts that will be reported include the size dependence of the quartz content, quartz variations with location in the mining section, and variations due to mining region. The results of the study show a strong pattern of size dependence of the quartz content in mines for which high quartz concentrations exist. A similar, though less pronounced, pattern exists in mines chosen at random. Quartz levels appear to have a varying relationship to section location and strong geographical patterns do not appear to exist in the data collected. Kaolinite content was found to be similar to that of quartz with patterns that are somewhat more consistent."

Jan 1, 1989

By E. E. Maust

The literature on the activation of sphalerite for flotation by short¬chain xanthates leaves unanswered the question of whether a compact surface film of activator sulfide is necessary or merely sufficient for high flotation recoveries. Studies by Guarnaschelli and Plaksin indicate that xanthate adsorption and flotation of sphalerite are increased with increasing hole/ electron ratio. These results, and the known acceptorlike behavior of many heavy-metal impurities in zinc sulfide, suggest that activation may result from a traditional semiconductor doping effect at the surface. Using the theory of chemisorption states on ionic crystals as developed by Levine and Mark, the Bureau of Mines has carried out A calculation to estimate the surface-state energies of various metals when they are substituted at zinc sites on (110) sphalerite surfaces. Based on a simple Madelung-Born treatment of ionic solids, the calculation indicates that many of the metals known to activate sphalerite for subsequent flotation have lower surface-state energies than nonactivators. The results of these calculations are discussed from the standpoint of consistency with the proposed activation mechanism and observed flotation results. The satisfactory agreement obtained is taken to be support for the proposed mechanism, and further elaboration of a surface-doping model is attempted.

Jan 1, 1976

By Wm. W. Odell

A study of certain gas making and fuel problems peculiar to the gas industry of California has been made by the Bureau of Mines. The work was done at the request of, and in cooperation with The California Gas Research Council 2, for the purpose of obtaining basic information on the gas-making fuels available to California, and their applicability to the present and future needs of the gas industry in that State. The data obtained have been applied in outlining a construction program, and indicate the possibilities in efficiently utilizing fuels in making gas by other than the oil-gas process. This paper presents an outline of the study and a summary of the principal results obtained, with some of the more important conclusions and recommendations based on this data. Gas is produced in California by processes which are both unique and different from those common to other parts of the United States. The bulk of the manufactured gas is made in and distributed from two main districts which are centers of population - namely, the Los Angeles district and the San Francisco Bay district. The gas manufactured in the Bay district is, almost exclusively oil-gas, whereas that produced in the southern part of the State, where natural gas is available, is mostly mixed natural gas and reformed-gas, but oil-gas is the chief product when the supply of natural gas is inadequate. Practically all of the gas companies are equipped with oil-gas generating apparatus, and anticipate using it in the future. As the continued use of the oil-gas process to the exclusion of all other processes, depends upon a continued supply of oil at a low cost, and the prospect of obtaining such low-priced oil in the future is somewhat uncertain, the questions have arisen: What will the future gas-making process or processes be? When will it be necessary to make plans for the installation of different gas generating equipment, and what will that equipment comprise?

Jan 1, 1926

By Bernard Porter

The solubility of UO2 was determined at 1,250° C. in ternary melts of UF4 and BaF2 with CaF2, LiF, and SrF2. The solubility of Ce02 was measured at 800° and 850° C. in a solution of CeF3, BaF2, and LiF. The amount of La203 which dissolves at 950° C. in a binary mixture of LiF and LaF3 and a ternary of LiF, LaF3, and BaF2 was also measured. In each case, the amount of soluble oxide was mound to be less than 5 weight-percent. A procedure was developed for filtering fused, oxide-saturated fluoride melts in order to obtain a representative sample for chemical analysis. The oxide content of the samples was determined by an inert-gas fusion procedure.

Jan 1, 1961

By D. J. Parker

Ability to signal the hoisting engineer in shaft mines is of utmost importance from the standpoint of safety and economy. The problem of signalling from the cages and especially from the moving cages has received too little attention from mine operators; however, this problem has been given considerable thought and attention by at least one large metal-mining company in Utah which has devised successful, economical, and safe systems of signalling from the cage whether it is moving or at rest. A Report of Investigations on "Methods used in Utah for signalling mine hoists from moving cages," by C. A. Allen, then a metal-mining engineer in the Bureau of Mines, was issued in June, 1920. As this report contains interesting history of systems of signalling from moving mine hoists, and describes several systems then in use, it is here quoted in full.

Jan 1, 1929

By H. R. Hardy Jr., E. J. Kimble Jr., H. W. Shen

"The primary objective of this research project is to study the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. Secondary objectives include the investigation of the acoustic emission technique as an indirect method for coal dust characterization and remote bit wear monitoring. The results of the project will be useful in developing efficient coal cutting techniques which significantly reduce the harmful coal dust components, and in providing methods for remote monitoring of bit condition and associated coal dust character. This paper will outline recent experiments carried out on coal under uniaxial compression, linear single-bit cutting, and cutting using a laboratory-scale, single-bit shearer. During the experiments acoustic emission and a variety of other mechanical parameters were monitored. · A commercially available artificial intelligence computer package, namely: JCEPAK (Intelligent Classifier Engineering Package), has been utilized to provide a powerful and objective means for AE waveform analysis. This program is able to evaluate a number of features of each AE event and to make objective comparisons between AE signals associated with different loading or cutting parameters. Finally, the paper will discuss the results obtained from a variety of coal breakage tests.INTRODUCTIONStudies to date clearly indicate that the reduction of the severity, and eventual elimination, of Coal Workers' Pneumoconiosis (CWP) depends on gaining fundamental understanding in a number of major areas. These include dust generation and entrainment, transportation, suppression, medical effects of dust and possible treatment. At present a project is underway by the authors to investigate the character of the bit-coal interaction during coal cutting and its influence on the size and shape distributions of the generated dust. An important aspect of this on-going project is the development of acoustic emission (AE) criteria which will make it possible to carry out remote monitoring of coal cutting operations. Suitable on-line analysis of monitored AE data would allow engineers to evaluate factors such as shearer bit condition and cutting efficiency, and to quantify the particle size and shape distribution of the generated dust. The on-going AE studies are fundamental in form and were undertaken to evaluate the general feasibility of AE monitoring techniques using simplified coal cutting procedures. This paper will outline recent experiments on coal under uniaxial compression, linear single-bit cutting, and cutting using a laboratory-scale, single-bit shearer. Additional information on these studies are presented elsewhere [4]."

Dec 1, 1996

By H. Robert Ensminger

As a result of the new mining law implemented in August 1985 and the programs conducted by the Institute Ecustoriano de Mineria (INEMIN), which was created by this legislation, there was considerably greater activity in the nonfuels mineral sector during 1986. Over the next 2 years, INEMIN will be developing a national mining plan that will guide Ecuadorean mineral development for the balance of this century. As stage one of INEMIN's mineral study, historical records were reviewed and 300 abandoned mines and 1,200 unexplored mineral deposits were available for further investigation. In 1986, INEMIN established 5 branch offices and negotiated 250 new mining contracts with foreign companies valued at $16 million. Despite all this activity, INEMIN officials estimate that 100,000 square kilometers remain available for claim staking. Technical assistance contracts were signed with Belgium, the Federal Republic of Germany, Italy, Spain, and the United Kingdom, to assist in a variety of assignments ranging from helping prepare the national minion plan to the development of industrial mineral deposits.

Jan 1, 1988

By J. D. Marchant

In the spring of 1953 a series of heats were made using a 3-phase, size ST, Pittsburgh Lectromelt arc furnace to develop a method suitable for melting, refining, and granulating cobalt powder produced by the Calera Mining Co., at Garfield, Utah. According to specifications stipulated by General Service Administration, the granules had to pass a 2-inch screen and be retained on a 6-mesh screen, be low in phosphorus and sulfur, and contain a minimum of 98.7 percent cobalt plus nickel. Various combinations of water temperature, water jets, and rate of pouring were tried early in the campaign to produce desirable granules. It soon became evident that a properly refined and deoxidized molten bath was the major requirement for a satisfactory product. The physical characteristics of the granules were improved also if, just before pouring, the surface of the molten metal bath was pre-pared by a method involving the use of silica flux. The Bureau processed 107,750 pounds of cobalt powder. A total of 104,810 pounds of cobalt granules meeting General Service Administration specifications was returned to the producer. The refining slag, which was also returned to the company, contained 1,781 pounds of metal.

Jan 1, 1955

By Wilbur I. Duvall, Thomas C. Atchison, Joseph M. Pugliese

Short cylindrical charges were detonated in drill holes in rock to determine the effect that decoupling ( defined as the ratio of the radius of the hole to the radius of the charge ) has on the strain - generating abilities of explosions in rock . The amplitude and period of the strain pulses produced in the rock were studied as a function of distance , size of charge , and decoupling . The main results of these studies were that , for a given distance and size of charge , the amplitude of the strain pulse decreases as decoupling increases and the period of the strain pulse decreases at first and then increases as decoupling increases . A simplified theory of decoupling is presented that satisfactorily explains the experimental results . The information presented makes it possible to predict the effect of decoupling on explosiongenerated strain pulses in rock and thus helps the explosives user evaluate the effect of decoupling on his blasting .

Jan 1, 1964