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By Shail J. Butani

In 1986, the Bureau of Mines conducted a probability sample survey, Mining Industry Population Survey, to measure such employee characteristics as occupation; principal equipment operated; work location at the mine; present job, present company, and total mining experience; job-related training during the last 2 yr; age; sex; race; and education. The population estimates are necessary to properly analyze the Mine Safety and Health Administration (MSHA) injury (includes illness and fatality data) statistics; that is, to compare and contrast injury rates for various subpopulations in order to identify those groups that are exhibiting higher than average injury rates. This report uses the survey's results to characterize the U.S. coal mining workforce from March through September 1986. A companion report, Information Circular (IC) 9193, "Characterization of the 1935 Metal and Nonmetal Mining Workforce:' provides similar information for the U.S metal and nonmetal mining industry.

Jan 1, 1988

By A. C. Fieldner

This report, the third of a series of annual reports of research and technologic work on coal by the Technologic Branch to be released in this form, covers the fiscal year July 1, 1937, to June 30, 1938. Ever-increasing demands for information on the chemical and physical properties of coals, their proper classification rind adaptability for various uses, their economic evaluation in the complex relationships between the costs of production, distribution, and selling, and their beneficiation and amenability to conversion to more valuable and. new products of commerce have necessitated an appropriate and flexible program. To most these requirements, initiation of new projects and new physical facilities has been made.

Jan 1, 1939

By Francis C. Lincoln

"INTRODUCTION As part of a general investigation of the zinc-producing area of southwestern Wisconsin, the Bureau of Mines undertook a limited amount of exploratory drilling in the immediate vicinity of the New Dale Rundell mine, in the Mifflin District of Iowa County, Wisc.The work was carried out during the early part of 1945, at a time when all effort was being directed toward increasing production of metals important to the Nation's war program. Bureau of Mines engineers decided to conduct exploration at the New Dale Rundell mine after a preliminary study of available data showed a reasonable possibility of indicating an important deposit. Before the Bureau of Mines investigation, 50 holes had been drilled in the vicinity. Of this number, 18 encountered ore of minable grade. Subsequently the mine was developed and operated for a brief period; however, work was stopped before all of the ore disclosed by drilling had been mined. There appeared to be a correlation between the ore shown by the drilling in the New Dale Rundell mine and another disclosure some 1,500 feet to the northwest. The Bureau of Mines exploration was pinned to explore this possible correlation. Of the 7 holes drilled by the Bureau of Mines, 3 disclosed minable ore beyond the limits of previous drilling."

Aug 1, 1946

By David E. Kaslow

In sampling dust laden air by drawing the medium into an inlet, some larger particles fail to follow the air and a true sample is not obtained. Inertia prevents particles from accelerating with the air as well as from turning sharp bends; also the particles' weight causes them to fall relative to the air. An analytic solution to the sampling efficiency calculation by Levin gives particle paths and sampling efficiencies for various particle sizes when the inlet can be treated as a point sink. However, the flow field in the neighborhood of an aspirating tube is quite different from a point sink flow. Employing Levin's solution in the outer field, trajectories in actual flow fields have been calculated by computer to locate the critical trajectories separating the entering particles I paths from those paths where the particles hit the tube wall or escape. Sampling efficiencies are presented in terms of 3 variables--a dimensionless particle size coefficient, a dimensionless orifice size coefficient and the tube orientation--for the no-wind case. Over most of the range of sampling conditions, the Stokes drag law can be used and dependence on the variable--particle Reynolds number--can be ignored. A procedure for achieving maximum efficiency in design of a sampler is proposed. Whether these results apply when typical room-sized eddies constitute the ?calm air? environment is not known.

Jan 1, 1974

By Forrest T. Moyer

All general measures of the safety record of the coal mining industry worsened appreciably in 1970. Injury experience for the year was 260 fatal and 11,552 nonfatal injuries at respective frequency rates of 1.00 and 44.40 per million man-hours of worktime. The fatality total was 57 higher and the rate of occurrence was 18 percent higher than the corresponding figures of 203 fatal injuries with a frequency rate of 0.85 in 1969. The worsened fatality record in 1970 resulted primarily from a major disaster (a single accident which results in the death of five men or more) on December 30, 1970, that killed 38 men. There were no major disasters in 1969. The total of 11,552 nonfatal injuries in 1970 was the highest annual total since 1960. It was 1,635 higher and the frequency rate was 6 percent higher than the corresponding totals for 1969 of 9,917 nonfatal injuries occurring at a rate of 41.76. The injury severity rate of 8,308 days lost or charged per million man-hours was 13 percent worse than that of 7,359 in 1969. Similarly, the average severity of 183 days lost or charged per injury in 1970 was 10 days or 6 percent higher than in 1969. Aggregate worktime of 260.2 million man-hours and production of 609.8 million tons in 1970 were, respectively, 10 and 7 percent higher than in 1969. An average of 144,480 men were at work on an average of 227 active days in 6,316 mines and 544 mechanical cleaning plants during 1970.

Jan 1, 1973

By Clayton R. Morlock

Airblasts have been monitored at four coal strip mines and at a limestone quarry. Thirty-seven production blasts have been monitored with three seismographs, resulting in one hundred and eleven complete air pressure records. Instrumentation selection use is described. Data analysis includes an assessment of the predictability of peak overpressures by means of the cube root scaled distance law. It is found that predictability for the cases studied here is not good. An extensive discussion of possible explanations is included. A detailed analysis of the frequency content of the observed airblasts, of considerable importance in evaluating potential annoyance problems, has been made for all records. A computer program has been written to simulate airblasts induced by multiple-hole blasts. A series of small experimental blasts have been detonated and monitored in order to allow an assessment of the program. It is clear that airblasts, especially when induced by very small charges and monitored at very close distances, are highly sensitive to detonation times. Retrofitting of airblast records occasionally was possible, but considerably improved field work is required to validate or refute the computer model.

Jan 1, 1983

By G. S. Scott, W. J. Huff, G. W. Jones, R. E. Kennedy

"INTRODUCTION This report gives preliminary results of field and laboratory investigations made at the request of the War Production Board relative to causes that have occurred during the last 8 months in acetylene-generat72,r plants in shipyards on the Pacific coast.Six acetylene-generator explosions have occurred in four shipyards. These explosions killed five operators, injured six others, and extensive damage to the plants involved and curtailmnent of vital defense Although the occurrence of acetyiene-generator explosions in other section of the United States is not known, it appears, at least, that if such have occurred, they have caused only minor damage and no loss of lives.The use of acetylene in shipyards on the west coast has expanded tremendously during the past 2 years. These shipbuilding, companies erected aletylene-generatcr equipment, which was soon found to be entirely inadequate to meet the needs of their expanding acetylene requirements for welding, cutting, shrinking, and other purposes, and instances found it necessary to operate their equipment at rates greater than deemed consistent with safe operating practice."

May 1, 1944

By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining the potential for reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/ lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978

By B. J. Moore

This publication contains routine analyses and related source data for 528 natural gas samples from 21 States collected during calendar year 1965 as part of a continuous survey of the United States for occurrences of helium in natural gas. This survey has been conducted by the' Bureau of Mines since 1917. The analysis published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4863 and 576.4

Jan 1, 1966

By B. J. Moore

This publication contains routine analyses and related source data for 528 natural gas samples from 21 States collected during calendar year 1965 as part of a continuous survey of the United States for occurrences of helium in natural gas. This survey has been conducted by the Bureau of Mines since 1917. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4863 and 576.4

Jan 1, 1966

A general description of investigative work conducted by the Bureau of Mines at the, Missouri Valley. manganese deposits and leading to tonnage and grade estimates has been given in Report of Investigations 4375, part 1 of a three-part report of work done between July 1945 and August 1947. Basic factual information from which tonnage and grade estimates were drawn was derived through the drilling sampling of 238 large-diameter bucket-drill holes in 11 widely separated areas. Drilling areas were selected after careful reconnaissance, mapping, and consideration of earlier work done on the deposits by the Bureau of Mines, State agencies, and private organizations and individuals. Stratigraphic studies permitted extending the results compiled within the drilling; areas to outcrop and lightly covered manganiferous zones between an beyond drilling areas. The locations of drilling areas, drilling sections, and individual drill hues are shown on illustrations in part 1 f this report. The individual drill holes, aside from providing the basic information for tonnage and grade estimates, disclosed features affecting any future plan As exploitation. It in particularly significant that a large part of the visible outcrops is faulted end otherwise complicated by slides that give a false impression of the thickness, vertical location, and even the existence of manganese-bearing zones.

Jan 1, 1949

By Wilbert J. Huff

The Explosives Division of the United States Bureau of Mines makes certain laboratory and field investigations that deal with explosions, explosives, ignition, and combustion, together with many related problems, such as the cause and prevention of fires, and certain fundamental scientific questions bearing upon the determination of the chemical and physical mechanisms underlying some of the important phenomena encountered. Its work on explosives has been particularly directed toward determination of the chemical and physical characteristics of explosives designed for use in coal mines and in a more limited way to those used in metal mines, tunnels, quarries, and other engineering operations. This testing is handled by two units of the Explosives Division, as follows:

Jan 1, 1937

By L. A. Stinnett

An investigation of hazardous surface openings of abandoned and inactive underground mines in the Black Hills area of South Dakota has revealed: (1) tracing legal ownership of mineral claims via county courthouses is confusing, complex, and oftentimes misleading, (2) in general, the selected mine openings in this investigation are to be considered relatively high in risks and hazard potential which poses a threat to the general public, (3) mine closure procedures and designs can generally be categorically implemented depending on the overall situation of the particular mine opening with subsequent unit costs estimates, (4) few preventive state or federal legal measures exist to date concerning mine closures, and (5) liability damages relating to mine opening accidents usually involve expensive and complex common law cases.

Jan 1, 1979

Surface mining and reclamation of a southeastern Ohio site with sandstone-shale overburden resulted in (as compared to premining levels): 1) runoff volumes and peak rates that increased by a factor of from 2 to 10 during mining and after reclamation, 2) destruction of the "aquifer" perched on the underclay of the mined coal bed and gradual, but, as yet incomplete redevelopment of this aquifer after reclamation, 3) no immediate effect on another, lower perched "aquifer", 4) up to 100 times greater sediment concentrations in runoff. Results were influenced by increasing annual precipitation amounts through the period of record; 1978, 1979, and 1980 (postreclamation years) experienced precipitation amounts approaching or exceeding long-term normalcy for the area. Part of the reason that the site produced more runoff after reclamation than before mining is that the premine condition was one of an open, porous soil under woodland, while the postreclamation condition was one of a compacted, bulldozed soil. Sediment concentration results were influenced by failure of the postreclamation erosion control system and by a series of detention reservoirs above the stream monitoring station.

Jan 1, 1983

By John R. Troxell

"INTRODUCTION The Ahles iron mine, also known as the Pequest mine, in Warren County, N. J., was operated continuously for 15 years and was still in ore when it closed in 1916.Tie property was examined by an engineer of the Bureau of Mines in March 1943. 3/ This examination led to an investigation of the deposits by the Bureau by diamond drilling two holes under the old workings to determine whether the extends downward.This report describes the work done at the Ahles mine by the Bureau and presents the data obtained.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report.The Metallurgical Division, O. C. Ralston, chief, analyzes samples and performs beneficiation tests.The investigation was under the general supervision of J. B. Zadra, acting regional engineer, and under the immediate supervision of G. D. Jermain, district engineer for the States of Pennsylvania, New Jersey, Maryland, and Delaware. The author was in direct charge of the project.The chemical analyses for the project were performed at the College, Park, Md., laboratories of the Bureau of Mines under the direction of M. S. Sheftel. The ore-dressing tests were conducted at College Park under the direction of Frank Lamb. Preston E. Hotz, of the Federal Geological Survey, logged and interpreted the drill cores."

Apr 1, 1948

A series of laboratory evaluations examined the impact of water spray pressure, curtain setback distance, and external and underboom spray use for controlling respirable dust levels and sulfur hexafluoride tracer gas concentrations around a continuous mining machine. This mining machine was equipped with a flooded-bed dust scrubber and was positioned in the box or slab cut. Exhaust line brattice was used for all tests. Dust levels were measured in the return airway and at locations representing the operators of the continuous mining machine and the standard and off-standard shuttle cars. Increasing water pressure or using the underboom sprays produced no significant impacts on dust levels, although their interactions did produce some significant impacts. Increasing curtain setback distance often elevated dust levels, likely by reducing the amount of airflow reaching the face. Use of the external sprays created additional airflow around the mining machine that pushed the dust cloud past the scrubber inlets. This significantly increased dust levels at all sampling locations. Tracer gas levels were measured on the off-curtain and curtain sides of the cutter head and in the return airway. Increasing water pressure generally led to significantly increased gas levels on the curtain side, although a slight decrease was observed on the off-curtain side with the machine in the box cut. Increasing setback distance elevated gas levels on both sides of the cutter head and in the return by limiting the quantity of ventilation airflow reaching the face. Use of the external sprays provided additional airflow along the off-curtain side of the machine, significantly reducing gas levels in this region. These sprays adversely impacted the dilution and removal of gas on the curtain side of the cutter head. Use of the underboom sprays adversely impacted gas levels on both sides of the cutter head. Use of the external sprays provided the best control of respirable dust and face gas concentrations. The smaller increases in miner operator dust levels produced by these sprays were offset by larger reductions in face gas levels on the off-curtain side of the cutter head. Although the underboom sprays minimally impacted respirable dust levels, use of these sprays was not recommended because they increased face gas levels.

Jan 1, 2007

By Albert L. Toenges

The Deep River coal field is in Chatham, Lee, and Moore Counties, N. C. The coal-bearing part of the basin is about 35 miles long and 5 to 10 miles wide. Sanford, the county seat of Lee County, is the largest town in the area, with a population of 10,000. Four railroads provide transportation to the area, and four United States highways and improved county roads provide easy access to the field. The Carolina mine at Farmville is the only operating mine in the field. The mine was opened in 1921 by two rock slopes driven from the surface to the Cumnock bed. Mining operations continued intermittently until 1945 and then stopped. In the fall of 1947 the mine was reopened by the newly organized Raleigh Mining Corp.

Jan 1, 1952

By Robert H. Peters

Groundfall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from the Mine Safety and Health Administration (MSHA) indicate that approximately half of the victims of these fatal accidents were in an area where no devices had been installed to support the mine's roof. This report was prepared by the U.S. Bureau of Mines to summarize the opinions of 268 coal miners, 29 rust-line supervisors, and 30 MSHA inspectors concerning why people go under unsupported roof, and how to prevent this behavior. Interviews were conducted at six minesites.

Jan 1, 1991

By A. W. Frolli

This paper, describing the open-cut mining milling, and cyaniding methods and costs at the Yellow Aster gold mine, is one of a series being prepared by the Bureau of Mines on similar practices in the United States. It is presented primarily to show methods and costs of mining and treating low-grade gold ore on a large scale.

Jan 1, 1940

By John P. Wagner

The details of a three-phase study (total time period of 12 months) entitled ?Fire Alert Systems for Metal and Non-Metal Mines,? are presented. Phase 1 consists of a state of the art survey on fire detection devices and gas sensing techniques. Phases 2 and 3 include laboratory screening and systems concepts testing on various detectors classified as products of combustion, optical view-field and contact (or thermal) types under incipient and flaming combustion conditions. Recommendations for a mine fire detection system to protect shaft, sealed off or mined out (from spontaneous combustion of sulfide containing ores and cellulosic materials), and fuel storage areas are also included. me principal problem area noted during Phase 1 study is the high expected occurrence of false alarming of products of combustion detectors (POC") subjected to normal mining operations---diesel vehicles and equipment and shot firing or blasting operations. Simultaneous gas sensing of either the ratio of CO/NOx or CO2/NOx with detection of one or more fire signatures (smoke, radiant energy, or heat sensing) is the recommended approach to discriminate against these operations.

Jan 1, 1975