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By E. J. Gleim

Many people consider the mining of coal to be an extremely hazardous occupation; but it should be remembered that most large industries have to meet special conditions which, if not dealt with properly, might become hazards to life and property. Mining men may not always be fully aware that some practices and certain equipment that is incorrectly designed or maintained can lead to dangerous conditions. In endeavoring to help the coal-mining industry to prevent accidents and disasters, the Bureau of Mines has engaged in a program of education on conditions and practices that must be avoided. An effective way to teach safety is by visual demonstration. For example, it is generally known that certain kinds of electrical flashes have ignited explosive atmospheres in mines, but actually to see and hear explosions caused by electrical sparks of different size and character under laboratory control is likely to teach a much more emphatic and lasting lesson than would be learned by merely reading about them. The interest manifested by those who witness the demonstrations seems to prove that this is true. The purpose of the demonstrations is not to discourage the use of electricity in mines, but rather to indicate what types of equipment (including some generally regarded as harmless) can ignite gas and what safeguards have been developed to prevent such ignitions. It is hoped that this information will improve the ability of mining men to cope with underground hazards.

Jan 1, 1937

By John H. Soulé

"INTRODUCTION Spodumene and lepidolite were shipped from the Harding pegmatite deposit, Taos County, N. Mex., in the period from 1930 to 1930. Tantalum minerals were noted as early as 1924 and described in 1931 3/ but no tantalum ore was shipped until 1942. The deposit was mapped and studied by geologists of the Federal Geological Survey and engineers of the Bureau of Mines late in 1942 and early in 1943, and a Bureau of Minus exploratory project was carried out in 1943. 4/ Thu following report presents the results of that project.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Minos has as its primary objective the more effective utilization of our mineral resources to the end that they make the greates possible contribution to national security and economy. It i the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lovell B. Moor, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallugiical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, Assistant Director."

Dec 1, 1946

By Alexander L. Peyton

The Magruder and Chambers copper deposits in the Little River gold district, on the border line of Lincoln and Wilkes Counties, Georgia, have been known for a number of years (fig. 1). The Magruder deposit was first opened as a gold mine but has produced mostly copper and load. Records show that about 50 cars of concentrates were shipped from this property. No record of any production at the Chambers deposit is available. The Bureau of Mines, in its program of investigation of strategic minerals deposits, diamond drilled 10 holes, totaling 3,784 feet, on the two properties between December 3, 1948, and June 23, 1949. Eighty-eight core samples were analyzed, and the analyses and drill-hole data are presented in this report.

Jan 1, 1950

By William G. Pariseau

The research reported here concerns a four year study of the rock mechanics aspects of two underground hardrock mine study stopes. The first study was conducted at Anaconda Minerals Company's Carr Fork Mine near Tooele, Utah. The second study was conducted at the Homestake Mining Company's Homestake Mine In Lead, South Dakota. Both case studies were cooperative efforts of mining company personnel, the Spokane Research Center of the Bureau of Mines and the Department of Mining Engineering, University of Utah. Large diameter (6 1/2 In.) blastholes were an integral part of the stoplng method at each mine. A true vertical crater retreat (VCR) method was used at the Homestake Mine, while a vertical bench mining method (VBM) was used at the Carr Fork Mine. VCR and VBM methods were developed In the 1970's; they offer significant productivity gain and are now used throughout the world. The new technology, however, brings with It a requirement for more sophisticated engineering design and control. Since there are no personnel in a VCR or VBM stope, all ground control Including dimensioning of stopes and pillars and the layout of cable bolt assays or other artificial support must be done in advance of production blasting. Accordingly, the objective of the research study was the establishment of a procedure for optimizing stops and pillar sizes. The approach taken was In each case a combination of mine measurements of the study stope response to mining, laboratory testing for rock properties and In situ stress measurements of the premining stress field, and theoretical calculations of the study stope response to mining. All calculations were done with the UTAH-II finite element computer program. Simulation of the blasting sequence gave a correlation of 0.88 between measured and calculated extensometer readings (Incremental relative displacements) at the Carr Fork Mine where other 30 Instrumentation boreholes were used to monitor the test stope response. A correlation of 0.84 was obtained at the Homestake Mine where 19 instrumented boreholes were used for monitoring purposes. These high correlations validated the computer mode and calibrated It for rock mass properties. The calibrated model was then used In parametric studies of alternative design layouts.

Jan 1, 1985

By John B. Umhau

[' is ann.tal surve:' gives sta.tistical data regC:ll~dirg rims.ry and feCOA-dUTY or ~cra:p tin used in thL United States by industries anc. includcc dc..ta l' is ann.tal surve:' gives sta.tistical data regC:ll~dirg rims.ry and feCOA-dUTY or ~cra:p tin used in thL United States by industries anc. includcc dc..ta ]

Jan 1, 1938

By Donald F. Reed

In its program of investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling from October 1247 to March 1948 at the Pickering Creek deposits, Charter County, Pa., in an endeavor to find an additional source of supply of lead and zinc. Lead mining in Pickering Creek Valley showed great activity from 1851 to 1855; but after this period mining gradually declined until 1870 when all mines were. One small mine did some work from 1917 to 1920. The ores were sulfides of lead and zinc, which were partly oxidized from the surface to the 20-foot level. As zinc was penalized at the reduction works, the ore was sorted at the mine and the zinc discarded. The Wheatley and Chester County veins contained the beet ore bodies in the district. These converging veins are 2 to 5 feet wide. To cut the veins below the old mine working' the Bureau of Mines diamond-drilled eight holes aggregating 2,820 feet. No significant lead-zinc mineralization was found.

Jan 1, 1949

By R. E. Head

This paper embodies the data obtained by a detailed statistical, microscopic analysis of the composite mill feed concentrate, and tailing, from the Magne and Arthur mills of the Utah Conger Co. for 1 month in 1929. It is one of a series of papers by the same authors dealing with the mineralogical characteristics of the ore and concentration products from various well-known plants. The work was done in the cooperative microscopic service laboratory at Salt Lake and represents the results of cooperation between the United States Bureau of Mines, the Utah Copper Co., and the University of Utah.

Jan 1, 1935

By Leon W. Dupuy

Marquette's first reported the existence of iron In Missouri in 1673. Recorded production wan begun in 1815, increasing in size and importance until 1888, when the low price of iron resulting from Minnesota's production of high-grade ore caused most of the operators to close down. Missouri's iron production came from three types of ore: (l) Brown ores, including the deposits of primary and secondary limonites in southeast and southwest Missouri, (2) hematites of the filled sinks, including the ores of Central Ozark district, and (3) specular ores in porphyry, including the deposits of the St. Francois Mountains.

Jan 1, 1949

As part of the Bureau of Mines subactivity in secondary resource recovery and to expand the Nation's mineral base, the Tuscaloosa Research Center made characterization and preliminary beneficiation studies of the waste residues from various coal-conversion processes: from pilot plant tests of the Synthane process for coal gasification, the Synthoil process for coal liquefaction, and the solvent-refined coal (SRC) process for sulfur removal from coal. Those coal conversion processes selected for this study were based on the availability of pilot plant samples. Physical, chemical, and mineralogical examinations of the wastes made to determine the mineral content prior to physical beneficiation tests indicated that in addition to significant quantities of carbon, some trace elements offer potential for concentration.

Jan 1, 1980

By Barry Beith

This report details a study which was designed to assess the effect of retroreflective material on detection and form recognition of workers in the mining environment. Further, the study attempted to determine an optimal configuration of retroreflective material with respect to amount and placement on the body to facilitate detection and form recognition. The study involved a one-fifth scale simulation of the perceptual task found in the underground low seam coal mine. Four different configurations of reflective material were presented in various body positions, common to low coal miners, at three different locations in the visual field, i.e., 10, 25, and 45 degrees from focal line-of-sight. All reflective configurations significantly improve detection and form recognition over configuration (cap only) worn by miners. As the amount of reflective material increased, accuracy also tended to increase. Based on the configurations investigated by this study, the Armband configuration (i.e., refectorized armbands, belt, self-rescuer and battery pack) was determined to be optimum. It is recommended that an actual field evaluation be made using the Armband configuration to establish if simulator results are generalizable to the underground mining environment.

Jan 1, 1980

By Homer J. Ballinger

A multiple drill carriage or "jumbo," which is believed to be unique in both design and performance, was constructed and has been in use for the past year at the Bureau of Mines experimental oil-shale mine near Rifle, Colo. This jumbo mounts four long feed percussion drills and is so designed that two men can operate all four drills. Before the jumbo was placed in operation, a minimum of eight man-shifts was required to drill 72 fifteen-foot holes in headings 60 feet wide and 27 feet high. The sane round is now drilled by two men in about 6 hours. Over 500 feet of drilling per man shift is easily and consistently accomplished. Use of the jumbo has resulted in a 75 percent reduction in drilling labor and a substantially lower drilling cost.

Jan 1, 1950

By Thaddeus B. Evans

This information circular is one of a series describing mining methods and costs, being published by the Bureau of Mines. The Sunbright mine of the Foote Mineral Co. at Sunbright, Va., is the southernmost underground limestone mine in the State. It is a comparatively recent operation, and a description of its rapid development to production stage may have particular interest for the limestone-mining industry. ACKNOWLEDGMENTS Acknowledgment is made to the executives of the Foote Mineral Company including F. B. Shay, vice president in charge of production, W. B. Towner, general production manager; and to the members of the company staff at Sunbright for their assistance in preparing this paper.

Jan 1, 1957

By W. F. Marshall

This Bureau of Mines report discusses tests conducted with four different catalytic reactor designs to determine the influences of exhaust treatment systems on emissions from diesel engines. Although there was significant differences in oxidation efficiencies at light to intermediate engine loads, all four catalysts were very effective in reducing emissions at heavy loads. Compositional determinations included carbon monoxide, carbon dioxide, unburned hydrocarbons, oxides of nitrogen, aldehydes, sulfur dioxide, sulfates, and particulate loading. Particulate size, exhaust odor intensity, and the character of the unburned hydrocarbon component were also determined.

Jan 1, 1978

By W. S. Sanner

Pyrolysis (destructive distillation) techniques developed at the Bureau of Mines to determine the yield and quality of the products from coal were used to convert municipal (household) and industrial refuse into potentially useful solids, liquids, and gases without adding to environmental pollution. The tests demonstrated that a ton of municipal refuse can be converted into 154 to 424 pounds of solid residue, 0.5 to 6 gallons of tar, 1 to 4 gallons of light oil, 97 to 133 gallons of liquor, 16 to 32 pounds of ammonium sulfate, and 7,380 to 18,058 cubic feet of gas. A ton of industrial refuse, consisting of paper, rags, and cardboard, can be converted to 618 to 838 pounds of residue, 1.5 to 3 gallons of light oil, 68 to 75 gallons of liquor, 12 to 23 pounds of ammonium sulfate, and 9,270 to 14,065 cubic feet of gas. The energy from the gas is more than sufficient to provide the heat for the pyrolysis.

Jan 1, 1970

By J. P. Rider

Health surveillance efforts indicate that the development of lung disease and overexposure to respirable dust in underground coal mires continues to afflict mine worker. Results from the most recent round (1992 - 1996) of the Coal Worker's X-ray Surveillance Programs indicate that approximately 8% of the examined miners who had at least 25 years of mining experience were diagnosed with Coal Worker Pneumoconiosis (CWP) (category 1/0+). During the period between 1995-1999, mine operators and MSHA inspectors collected 9968 and 1365 dust samples respectively, from longwall designated occupation (DO) personnel. Analysis of these samples showed that 1970 (20%) of the mine operator samples and 25.8 (19%) of the MSHA samples5 exceeded the 2 mg/m3 dust standard. The continued development of CWP in coal mine workers and the magnitude of respirable dust over-exposures in longwall mining occupations illustrate the need for improved dust control technology on longwalls. Figure 1 illustrates the major longwall dust sources as determined in the early 1990's.4 This article describes the ongoing research to find ways to minimise shearer dust levels as a function of changes in dust control parameters, and research to determine the impact of high air velocities on shield dust entrainment.

"While control of dust-related diseases, the objective of the Generic Mineral Technology Center for Respirable Dust, is of prime importance from the human standpoint it is also essential to the economic well-being of the mining industry (FIGURE 23). Although significant progress has been made, the problem continues to be a major concern to the mining community. An increasing global demand for coal and other minerals means that production and the number of miners employed is on the rise. Therefore, the importance of this research to the mining industry cannot be overemphasized.The five areas of dust research are 1) control of dust generation, 2) dilution, dispersion and collection of dust in mine airways, 3) characterization of dust particles, 4) interaction of dust and lungs, 5) relationship of mine environment, geology, and seam characteristics to dust generation and mobility. Some experimental projects where the research is conducted almost exclusively in the laboratory may still rely on industry for imput. No industrial resources are necessary to the research of the non-experimental projects, for example computer modeling .The remaining research is classified as experimental and these projects do require interaction with industry in varying degrees. Periodic trips to mining sites in Western Pennsylvania, Southern Ohio, and West Virginia are necessary to record measurements or collect samples. Or companies may provide needed samples or equipment to the university for use in the laboratory. On several projects interaction is limited to advice or information supplied to the researcher by industry personnel."

Aug 31, 1989

By C. N. Rosenecker

The power required to circulate a gas-solids suspension was determined using a centrifugal compressor and a closed system. The suspension consisted of 18- to 40-micron glass beads in a mixture of 89 percent N2 and 11 percent CO2 at 20 psig. Solids-to-gas (S/G) ratios w re O to 2.2 lb/lb; gas flow rates were l.2 to 2.5 lb/min. Power requirement was found to follow the relationship hp t = hp(. + l), where hp t = the total power, and hpg = the power required for pure gas.

Jan 1, 1967

[In selecting deposits of exploration projects, tabular deposits or large mineralized masses are favored because they may be explored systematically and because they afford the best opportunity for blocking out reserves in advance of mining, whereas irregular, small pipes and scattered]

Jan 1, 1941

By L. C. IlsLey

The United States Bureau of Mines has been conducting investigations of electrical equipment curing a period of more than 25 years in an endeavor to encourage the development of safer electrical equipment for coal mines. In order to conduct these investigations in an orderly manner they are carried out under a published schedule of tests known as Schedule 20, which specifies detailed requirements for motors, controllers, etc., and fees covering the various inspections and tests made as part of a routine investigation.

Jan 1, 1937

By D. J. Parker

Since the introduction of electricity into the mines of the United States , the hazards incident to the industry have increased materially in both coal and metal mines . For economic reasons the tendency at present , particularly in coal mining , is decidedly toward the adoption of electrical mine machinery , including alternating current machinery , on a more extensive scale than ever before . Obviously, the growing use of such equipment will result in an ever -increasing number of underground transformer stations . The principal electrical hazards in mines are threefold ; fire , explosion, and contact . Of these , fire is the greatest hazard involved in the use of electricity underground , and several fires have originated in underground transformer and motor generator set stations . The fire hazard due to improperly installed and poorly maintained underground transformer stations is an ever-present one , and failure to take the necessariman remedial action is likely to result , sooner or later, in the destruction of life and property . Upon suggesting the necessary corrective measures with respect to such installations , one is often confronted with the statement to the effect that even though this particular hazard has existed over a period of years , there have been no unfavorable results therefrom thus far . Frequently , the desirability for action is not apparent to the mine management until it is too late . Because a mine has a record free from fires , explosions , etc. , over a number of years of operation during which these hazards existed , such good fortune should not be taken as a guarantee that this or any other mine is immune from these common dangers . When the elements of an existing hazard are properly balanced or in the right proportion, the unfortunate combination must of necessity culminate in misfortune of one kind or another. The fire hazard due to underground transformer installations can be very definitely minimized by proper installation and maintenance . In coal mines the transformer banks , connected to 2,300 and occasionally to 4,400 volt circuits , are often found located in open- ended crosscuts , mounted on concrete or timber foundations , and in nonfireproof surroundings .

Jul 1, 1930