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By Khamis Y. Haramy

This U.S. Bureau of Mines report describes the use of Bureau-developed flat and cylindrical hydraulic borehole pressure cells. A brief description of the fabrication, installation, and pressurizing equipment is given and pressurizing procedures are discussed. Theories available on evaluation of data from the flat and cylindrical pressure cells and examples of data analysis and stress evaluation are also presented.

Jan 1, 1991

By Richard A. Allwes

The Bureau of Mines conducted an in-mine case study on two consecutive three-entry gate road systems designed in accordance with the stiff-yield pillar design concept. This Bureau study was conducted in order to further develop technology that will improve the health and safety aspects of longwall mining. Support loading and strata activity were monitored to determine the effects of retreat longwall mining on the gate road ground control system. Analyses of pillar stress and roof bolt loading histories revealed that headgate roof support elements ex-perienced cumulative loading throughout the life of the longwall panel. Tailgate pillar loadings had significantly different histories from the loading histories of the headgate pillars. Stress relief occurred in the tailgate pillars following the passage of the longwall face. More-over, the stiff-yield pillar design, with the abutment pillar placed adjacent to the working panel when part of the headgate system, provided effective ground control in that no major roof falls or roof problems were experienced in the headgate or tailgate systems during longwall mining.

Jan 1, 1985

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 F. G. Horino

The Bureau of Mines conducted compressive strength tests on model pillars of selected rock types with each pillar containing a critically oriented plane of weakness. The objective of these tests was to determine if a significant increase in the strength of the model pillar could be obtained by either (1) installing tensioned rock bolts through the pillar and normal to the plane of weakness, or (2) wrapping tensioned steel wire ropes around the pillar at uniformly spaced intervals along the pillar. Equations based on Coulomb's failure criterion are developed to predict uniaxial compressive strength of model pillars that are either rock-bolted or wire-roped. Laboratory compressive strength tests on unbolted and bolted model pillars of sandstone, marble, Indiana limestone, and oil shale containing a plane of weakness oriented at 45° showed that the bolted pillars are stronger than the unbolted pillars by 84, 31, 52, and 28 pct, respectively. Laboratory compres-sive strength tests on nonroped and roped model pillars of Texas limestone, sandstone, and granite containing planes of weakness showed that the roped pillars were stronger than the nonroped pillars by factors ranging from 1.01 to 2.41, depending upon the angle of the plane of weakness and the rock type. Rocks with a low Young's modulus benefited most by the wire-roping technique.

Jan 1, 1971

By Oliver C. Ralston

The Nonmetallic Minerals Division of the Bureau of Mines deals with all mineral substances not intended to be used as ores for extraction of metals, with the exception of the fuels. However, coal washing, the methods of which are highly Similar to the concentrating methods for ores, is in¬cluded In the work of the Nonmetallic Minerals Division to facilitate administration and to avoid duplication of equipment. During the fiscal year most of the work of the division was done at the experiment stations in College Park, Md., Tuscaloosa, Ala., and Seattle, Wash.

Jan 1, 1938

By Oliver C. Ralston

The Nonmetallic Minerals Division of the Bureau of Mines deals with all mineral substances not intended to be used as ores for extraction of metals, with the exception of the fuels. However, coal washing, the methods of which are highly Similar to the concentrating methods for ores, is included In the work of the Nonmetallic Minerals Division to facilitate administration and to avoid duplication of equipment. During the fiscal year most of the work of the division was done at the experiment stations in College Park, Md. Tuscaloosa, Ala., and Seattle, Wash.

Jan 1, 1938

By Ira L. Wright

This paper describing the milling practice of the Black Hawk Consolidated Mines Co., is one of a series being prepared by the United States Bureau of Mines. ACKNOWLEDGMENTS Part of the information contained in this paper was furnished by I. H. Stanley, mill superintendent, Black Hawk Consolidated Mines Co., Hanover, M. M., and a part by the South-western Engineering Corporation, Los Angeles, Calif. The assistance of T. G. Chapman in arranging the paper for publication is also acknowledged.

Jan 1, 1930

By Steven J. Schatzel

Prior research has suggested that the source of respirable silica dust in underground coal mines is typically the immediate top or bottom lithology adjacent to the mined seam, not mineral matter bound within the mined coal bed. Geochemical analyses were applied in an effort to identify the specific source rock of respirable quartz dust in coal mines. The analyses also demonstrate the compositional changes that take place in the generation of the respirable dust fraction from parent rock material. All six mine sites were mining coal with relatively low mineral matter content, although two mines were operating in the Fire Clay coal bed which contains a persistent tonstein. Interpretations of Ca, Mg, Mn, Na, and K concentrations strongly suggest that the top strata above the mined seam is the primary source of mineral dust produced during mining. One site indicates a mixed or bottom source, possibly due to site specific conditions. Respirable dust compositional analyses suggest a direct relationship between the quantity of mineral Si and the quantity of quartz Si. A similar relationship was not found in either the top or bottom rocks adjacent to the mined seam. An apparent loss of elemental Al was noted in the respirable dust fraction when compared to potential parent rock sources. Elemental Al is present in top and bottom rock strata within illite, kaolinite, feldspar, and chlorite. A possible explanation for loss of Al in the respirable dust samples is the removal of clays and possibly chlorite minerals. It is expected that removal of this portion of the Al bearing mineral matter occurs during rock abrasion and dust transport prior to dust capture on the samplers.

Jan 1, 2009

The first metal-mine accident-prevention course was prepared and published 1942-45 as a series of seven miners' circulars (Nos. 51-57). The course has been broadened, revised, and brought up to date and is being published as a similar series of seven miners' circulars on accident prevention at metal and nonmetallic mines. These circulars are: 1. Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents.

Jan 1, 1957

By Richard Quirk

This report describes methods and techniques employed by The Glidden Co. of Cleveland, Ohio, in explorating an ilmenite-bearing sand deposit in Ocean County, New Jersey, during 1960 to determine ore reserve potential and the feasibility of mining and establishing a milling plant on the property for the production of ilmenite concentrate. The property covered approximately 1,250 acres. Comprehensive sampling by water-jet drilling indicated the deposit averaged 20 feet in thickness and contained 4.5 percent heavy minerals, of which 80 to 85 percent was ilmenite and leucoxene. Average depth of the water table as determined by auger boring was 16.8 feet. Pilot plant tests indicated that circular concentrators in combination with spiral concentrators would recover at least 80 percent of the heavy mineral content of the sands. It was estimated that sufficient ore reserve tonnage had been developed to supply the company's Baltimore chemicals division, pigments department, with a suitable grade ilmenite concentrate for a period of 20 years at the present rate of pigments production. The property was designated as Lakehurst mine and plans are in progress for mining development and plant construction.

Jan 1, 1963

By Robert Vinson

This article examines the spatial variability of dust concentrations within a coal miner?s breathing zone and the impact of sampling location at the cap lamp, nose, and lapel. Tests were conducted in the National Institute for Safety and Health Pittsburgh Research Laboratory full-scale, continuous miner gallery using three prototype personal dust monitors (PDM). The dust masses detected by the PDMs were used to calculate the percentage difference of dust mass between the cap lamp and the nose and between the lapel and the nose. The calculated percentage differences of the masses ranged from plus 12% to minus 25%. Breathing zone tests were also conducted in four underground coal mines using the torso of a mannequin to simulate a miner. Coal mine dust was sampled with multi-cyclone sampling cans mounted directly in front of the mannequin near the cap lamp, nose, and lapel. These four coal mine tests found that the spatial variability of dust levels and imprecision of the current personal sampler is a greater influence than the sampler location within the breathing zone. However, a one-sample t-test of this data did find that the overall mean value of the cap lamp/nose ratio was not significantly different than 1 (p-value = 0.21). However, when applied to the overall mean value of the lapel/nose ratio there was a significant difference from 1 (p-value < .0001). This finding is important because the lapel has always been the sampling location for coal mine dust samples. But these results suggest that the cap location is slightly more indicative of what is breathed through the nose area.

Jan 1, 2007

By O. T. Barrett, R. F. Aberethy, H. N. Cooper, Thomas Fraer, William L. Crentz

"INTRODUCTION The object of the techniques described in this report is to determine the possibilities of separating the components of a raw coal into such grades as may be necessary to recover some exceptionally clean functions for special purposes.To do this commercial gravity methods would require separation at very low specific gravities, entirely outside the range of conventional practice. Hence, a technique has been developed for breaking down cool ample, into very close fractions within the gravity range of the (-lean coal matter as well as for separating it from the refuse and particles.Such data on the fundamental specific-gravity consist of the clean-coal matter will serve to appraise the difficulty of the problem and to chow be accomplished if and when effective methods of making such separations commercially are developed."

May 1, 1945

By Philip B. Grote

The deep ocean mining industry is in a pre-commercialization stage of development. In the context of a proper legal/regulatory regime, deep ocean mining system design, site survey, and operation technologies are capable of rapid evolution. The report recommends that the regulatory framework develop in parallel with the industry and presents a rationale for implementing this approach. The Government has several interests in deep ocean mining technology: (1) as a potential regulator, sound regulations should be based on an understanding of the technology; (2) as a potential monitor, survey technologies are relevant; and (3) as an estimator of strategic minerals supplies, it is important to understand the technology which allows economic access to deep ocean minerals. Thus, the major portion of the report presents an in-depth review of systems design, operations, and survey equipment and techniques.

Jan 1, 1979

By E. J. Murphy, John C. Holtz

"INTRODUCTION Toxic gases in the products from the detonation of explosives are one of the hazards in blasting underground. Investigations by the Bureau of Mines 4/5/ have shown that the oxygen balance of the explosive is an important factor in the control of toxic gases. This balance is considered in determining the composition of modern metal-mining explosives for blasting underground, and application of the concept has reduced the volume of toxic gases generated.The chemical nature of the material being blasted also influences the composition of the toxic gases produced. Under some conditions of blasting in massive pryrite, unsafe concentrations of sulfur dioxide and hydrogen sulfide have been found.Experiments with the O-J apparatus 8/ have shown that there is an increase in the volume of carbon monoxide in the gaseous products when permissible explosives are detonated in contact with coal dust. Thus, reactive materials of a reducing nature adjacent to explosives loaded in drill holes may decrease the effective oxygen balance of the explosive and cause the volume of toxic gases to increase.Several blasting accessories of reducing nature have been introduced recently for use in coal or metal mines or tunnels. In practice these are loaded adjacent to the explosive where conditions favor reaction with the products of detonation. The effects of this loading on the gaseous products obtained from the shot are indicated in this report. Broad consideration was not given the efficiency, usefulness, or over-all safety of these devices, but the practical significance of the hazard resulting from increased volume of carbon monoxide is discussed."

May 1, 1942

By C. J. Walker

The ever-increasing use off natural underground formations for storing natural gas has focused attention on the behavior of such storage formations under varying operating conditions. The need for a means of evaluating in¬dividual wells and groups of wells has become manifest. It is essential that industry and others be able to determine the rates of flow that can be ex¬pected from a given well or group of wells under different conditions and to ascertain whether certain wells are deteriorating. Such questions need more exact answers now than ever before because of the vital role underground gas storage plays in the industrial and domestic consumption of natural gas. The Bureau of Mines--in cooperation with the American Gas Association--has main¬tained an active interest in gas-well testing because of the implications of such test procedures on the consumption and efficient production of natural gas. A basis for testing gas wells was provided by the back-pressure method of Rawlins and Schellhardt (12).4/ They showed that for normal gas wells there is a consistent relationship between rates of delivery of gas and corresponding pressures when the formation pressures are used as the basis of interpretation, The equation for this relationship is as follows: Q = C (Pf2 - Ps2)n where; Q = rate of flow, generally expressed in cubic feet per 24 hours. C = a coefficient.

Jan 1, 1960

By David Schlain

"IntroductionThe purpose of this investigation was to study the characteristics of the high-acid electrolytic manganese cell with the idea of fitting it into one of the flow sheets being worked out by the Metallurgical Division of the Bureau of Mines for the recovery of manganese from low-grade domestic ores.In construction, the high-acid cell 3/ differs from the low-acid type in that the cathode and anode compartments are separated by a diaphragm of relatively low porosity, such as alundum. This is necessary because in the high-acid cell the two electrolytes are circulated separately. The anolyte is 15 to 30 percent H2SO4. The catholyte consists of a solution of ammonium sulfate and manganese sulfate with a OH of 4 to 3. The only mixing of electrolytes is that resulting from flow through the diaphragms. In the low-acid cell the two electrolytes are not circulated separately and do not differ so widely in hydrogen-ion concentration. Hence, the canvas diaphragm is sufficient.During operation of the cell, manganese is deposited on the cathode, and sulfuric acid is produced in the anode compartments. Various other reactions take place in the cell. There is considerable decomposition of water; hydrogen is evolved at the cathode, and oxygen is liberated at the anode. When lead anodes are used, some hydrated oxides of manganese are formed at the anodes. The quantity of oxides formed is not as great as it is in the low-acid cell, because fewer Mn++ reach the vicinity of the anodes."

Jul 1, 1942

The wealth of a nation can be measured many ways, but one of the most important measures is its natural resources, particularly minerals. Minerals provide the foundation upon which economic prosperity and defense preparedness rest. Assessing our energy and mineral resources and assuring their development is in the best interests of all our people continues to be an important national goal. Since its founding in 1910, the U.S. Bureau of Mines has established itself as the world&apos;s premier minerals information and research agency. Its authoritative, comprehensive data and pioneering research have contributed significantly to a strong U.S. mineral position in the world.

Jan 1, 1990

By Northcutt Ely

This volume summarizes mining and petroleum legislation in 30 jurisdictions of the Western Hemisphere. Within these jurisdictions, primary attention is given to requirements that must be met in each country for acquisition of rights to permit development of mineral resources. Coverage includes: First, identification of the controlling laws or statutes governing minerals acquisition and reference to the administrative authority; second, analysis of the laws governing mines and quarries and their products; and third, analysis of laws applicable to natural gas, petroleum, and related materials. Where pertinent, sections dealing with historical background or administration have been added. In countries where minerals are subject to control of States or Provinces, those areas are considered separately from the central government.

Jan 1, 1970

By D. W. Mitchell

This Bureau of Mines report summarizes experience and past research on methods for sealing abandoned areas of a coal mine and areas from which the pillars have been wholly or partially extracted. The Federal Coal Mine Health and Safety Act of 1969 requires that such areas be ventilated or sealed with explosion-proof bulkheads, but the present study indicates that bulkheads alone cannot isolate areas in a coal mine in which methane and other dangerous gases have accumulated. Gas-air exchanges between sealed and open areas must be controlled.

Jan 1, 1971

By Kenneth Eilerts

[Efficient and econonic production of ?etroleum requiros knowledge of the propertios of rescrvoir fluids a:$. their characterintics of flow throayh porous forclntions. The cllanga in propertie s and flow characteri s- tics of fluids when their corosition is altercd cs a rnsult of reservoir- pressure decliae is of &apos;mecial i~ortenct? ir, planning wall-spaAng pro.yama and production schedules. Rct~ntion of the ~eatent poscible quantity of dissolved gac in the rescrvoir liquid gnneml&apos;y is recognized cs ess~ntisl to mxim ultimzte recoverj of oil fro3 the underground reecrvoir. Ilo:rever, pro6uction mothodn tending to mintain gis in solution in the oil and re- sulting in the optimm ocolo~ic recgvery of oil not only vary from field to fiold but also my have to be changed from time to time in a given field as it is being depleted of its recoveraklo oil. Const vestly there is need tc investigztc tY.e propertiec of resa:-voir f kids corresponding to successivc stages of reservoir depleJ&ion with the view of obtnining infomation oacential to efficient prcriuctian practices.]

Jan 1, 1939