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By R. O. Pynnonen

This publication presents a study by the Federal Bureau of Mines of 494 accidents in open-pit iron-ore mines, beneficiation plants, and shops of the Lake Superior district from March 1949 to June 1956. These accidents caused 499 lost-time injuries, including 12 fatalities. A similar Bureau publication, Information Circular 7744, Analysis of 346 Accidents, Underground Iron-Ore Mines, Lake Superior District, was published in April 1956. Accident reports were analyzed by the Bureau to show the causes of in-juries and the unsafe practices or conditions that caused the accidents. Also shown are the time charges, times of occurrence, ages of the injured by job classification, and experience of the injured in mines and on the job being performed when hurt. Detailed information is presented on approximately 27 percent of the total number of disabling accidents that occurred in open-pit iron-ore mines, beneficiation plants, and shops in the district during the period covered. The text also contains tabulations of the accident experience and graphs with straight-line injury-frequency, injury-severity, and fatality trends for the period 1946-57.

Jan 1, 1959

By Stephen P. Signer, John L. Lewis

This paper presents the results of a case study conducted in a two-entry gateroad in a coal mine where excessive roof deformation and bolt loading resulted in failure of many roof supports. The instruments consisted of 16 fully grouted, strain-gaged resin bolts, load cells on both full and partially grouted cable bolts, and vertical deflection multipoint extensometers. These instruments were installed on-cycle to measure loading on bolts in an existing support pattern and to determine if cable bolts could be used to improve roof stability. Results showed significant amounts of movement within the bolted zone. In some cases, these movements were enough to load the supports past their ultimate strength. Geology appeared to be a significant factor in localized roof degradation; that is, a very weak rock layer in the immediate roof overlain by a very strong rock layer contributed to the development of shear planes. Only one instrumented bolt had a maximum strain of less than 2,000 microstrain, which was the yield point of the steel. The average maximum strain on all bolts was 20,000 microstrain. However, electrical continuity to many gages was lost and a pattern was noted that would indicate possible bolt failure. Wire mesh and concrete cans installed as secondary support performed very effectively.

By James A. Wasson

This report summarizes the results and conclusions reached by various investigators who have attempted to determine the extent to which hydraulic fracturing will affect the secondary recovery of crude oil by waterflooding. It also discusses the most advantageous use of this well-stimulation method in waterflood projects. A thorough search of the literature was made, and pertinent information was abstracted from appropriate reports. A carefully designed and controlled program of formation fracturing is an effective aid in waterflooding because it increases water-injection and oil-production rates. Generally, fracturing has resulted in little or no reduction in ultimate oil recovery, but under certain circumstances recovery has been substantially increased.

Jan 1, 1963

By F. E. Armstrong

An instrument using a gamma-ray backscatter technique for determining the weight-percent incombustibles content of coal dust and rock dust mixtures in coal mines has been built and tested. The unit gives a direct readout in per-cent incombustibles for coal mine dust mixtures containing between 50 and 100 percent incombustibles; calibration of the device requires using a sample of the rock dust employed; this is usually limestone but occasionally dolomite or gypsum. A small americium-24l source is used with a scintillation detector whose output feeds a rate meter. The source-detector geometry used was chosen to reduce the effects of variation in bulk density. Accuracy of the system is within ±3 percent for most mixtures. The instrument is portable and completely self-contained; the rechargeable batteries supply power for 300 to 400 determinations.

Jan 1, 1974

By Donald O. Capstick

A mineral resource evaluation of the Coyote-Southeast RARE II area (No. 5033) was performed jointly by the U.S. Bureau of Mines and the U.S. Geological Survey in 1981 for the U.S. Forest Service RARE II program. Bureau of Mines personnel conducted a mineral resource inventory of the study area's mines, prospects, claims, and mineralized outcrops. The study area's boundaries encompass 51,700 acres on the east flank of the Sierra Nevada and are within Inyo National Forest southeast of the city of Bishop in east-central California. Cretaceous granite underlies most of the area; the remainder of the rocks are metasedimentary. At the contact of the two, tactites formed at many places where carbonate rocks were present; replacement processes produced local scheelite (calcium tungstate) occurrences.

Jan 1, 1983

By R. B. Krog

As part of its mining health and safety research program, the National Institute for Occupational Safety and Health (NIOSH) conducted a longwall methane emission and mining time study at a mine operating in the Pittsburgh Coalbed to access the methane emission consequences of mining a longer face. The methane emission contributors from the mining of a longwall face are: 1) gas released from the coal broken by the shearer, 2) gas emitted from the coal on the face conveyor, 3) gas emitted from the coal transported on the belt, and 4) background gas emitted from the coal face and from the adjoining ribs. Based on the results of the study, a set of site-specific mathematical formulas and constants were developed to characterize each of the four longwall emission contributors. The mathematical formulas were then applied to longer longwall face mining scenarios to predict the methane emissions from these faces.

Jan 1, 2006

By F. A. Jones

Increased mechanization .of coal mines has emphasized the need for study of actual power requirements of the various machines employed in the production of coal and losses in the distribution of power to these machines. These studies are being made in order that hazards, excessive use of power, and high maintenance cost of equipment resulting from these losses may be analyzed and eliminated where possible. Research on the use of electric power in-coal mines was suggested by the Advisory Committee of the Bureau of Mines in 1937, and it was decided to begin with a study of individual machines of various types under operating conditions in modern coal mines. The transmission of power, particularly line losses and inadequate return circuits, should be a part of the investigation. This report presents some of the data of an initial study in commercial mines. ACKNOWLEDGMENTS The superintendents, engineers, and other officials of the two mines studied cooperated fully and aided in setting up and transporting the test equipment, giving such information as was requested.

Jan 1, 1942

By R. W. Lowe

1. Reserves are estimated in the Nemo, Sewanee, Wilder, and White Oak beds of Fentress County, Tenn. The Wilder is the only bed being mined commercially and contains the largest known reserves. Eleven lesser known beds are present in the county, but not enough information on them was available for estimating the reserves. 2. Known measured and indicated reserves, based on a minimum bed thickness of 14 inches and on 1,800 tons per acre-foot of coal in place, are estimated at 102 million tons as of January 1, 1955. This total includes 66 million tons in beds 28 inches and more thick.

Jan 1, 1956

By C. B. Davison

One goal of the Bureau of Mines is to conserve the Nation's mineral resources by developing improved performance materials. Consistent with this goal, the Bureau conducted studies on the formation of undesirable cristobalite in seven different fire clays used as refractories. The studies employed scanning electron micrography, chemical and X-ray analyses, and pyrometric cone equivalent determinations to examine the sample clays and determine the effect of thermal history and stablilizing additives on the amount of cristobalite in various calcines. This research has indicated that as fire clay calcining temperatures increased from 1390° to 1,490° C there was a gradual decrease in the percent of cristobalite present in the calcines and a progressive development of mullite crystallization. No cristobalite was found in fire clays calcined above 1,550° C, but cristobalite reappeared when the calcines were reheated to temperatures between 1,400° and 1,500° C. The research also revealed that additions of lithium fluoride (LiF) prevented formation of cristobalite in fire clay calcines.

Jan 1, 1979

This publication contains eight papers presented at a Bureau of Mines Technology Transfer Symposium in Charleston, W, on June 22, 1983, Five of the papers describe the results of Bureau-sponsored research on cabs and canopies for low-coal underground mining equipment. The other papers describe the efforts of three underground coal mining equipment manufacturers (FMC, Joy, and Lee-Norse) in the area of cab and canopy design.

Jan 1, 1985

By Jürgen F. Brune, Liming Yuan, Alex C. Smith

To provide insights and assistances for the optimization of ventilation systems for U. S. under-ground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study is being conducted to investigate the effect of the ventilation scheme on the prevention of spontaneous combustion in longwall gob areas. This report focuses on the flow patterns within the gob under three different ventilation systems; one-entry and two-entry bleederless systems as well as a three-entry bleeder system. The gas flow in the caved gob area is simulated as a laminar flow through porous media while the gas flow in ventilation airways is simulated as a fully developed turbulent flow. The air flow patterns are visualized using flow path lines. Air velocity contours and vector data are also obtained. The possible location of critical velocity zones where the gob is most liable to spontaneous heating is discussed.

By H. W. Wainwright

.1. The purification pilot plant and the equipment, solution, and gas cycle used for removing hydrogen sulfide and carbon dioxide are described. 2. As sulfur recovery is necessary in any large Fischer-Tropsch plant, pilot-plant runs were made at 300 p.s.i.g. to study the efficiency of tri-ethanolamine solutions in removing selectively hydrogen sulfide from gases containing varying amounts of carbon dioxide. 3. Aqueous solutions of TEA of 20, 30; 35, and 50 percent were investi¬gated. Data indicate that 30 to 35 percent is the optimum concentration if both selectivity and economy are considered. Slightly better selectivity is obtained with the.20 percent solution, but steam consumption is greater owing to the higher solution rates. Results from our pilot plant runs indicate that a 50 percent solution not only produces an acid gas of lower hydrogen sulfide content but also requires high solution rates to effect hydrogen sulfide purification. 4. Data from 37 runs using TEA are presented in tabular form. In addition, the data are correlated and presented in three sets of curves. By using these curves, it is possible to calculate the compositions of the purified and acid gases for various raw gas mixtures. 5. In cooperation with the Southern Natural Gas Co., investigations were carried out at 300 p.s.i.g. on the simultaneous removal of hydrogen sulfide and carbon dioxide, from gases using various concentrations of diethanolamine. 6. Data from 17 runs employing 20, 30, and 40 percent DEA are reported in both tabular and graphic form. 7. A comparison of the data from one DEA run made at 200 p.s.i.g. with those from the runs operating at 30O p.s.i.g. shows float the absorption capacity of the solution, and, hence, the steam requirements per gallon are about the sage for both pressures. .The only real advantage of the higher pressure is the additional volume of gas that can be treated. 8. The quantity of steam needed to reactivate fouled TEA and DEA solutions increased as the reactivator pressure was increased about 1,0 to 1.1 pounds of steam was required for each gallon of circulating solution when the reactivator was operated at 5 p.s.i.g. 9. A curve is included that shows the effect of the hydrogen sulfide con-centration in a lean 35 percent TEA solution on the hydrogen sulfide content of the purified gas and on steam consumption for reactivation. 10. Both TEA and DEA reduced the organic sulfur content of the raw synthesis gas considerably. Analyses of the lean amine solutions showed a gradual build up of sulfur compounds, indicating that the compounds formed by the amines and organic sulfur do not break down under the ordinary operating conditions of the reactivator. 11. Considerable operating difficulty was encountered in the pilot plant owing to foaming of the amine solutions. Laboratory experiments in which the effectiveness of certain antifoam agents was studied showed Alkaterge C to be most promising for the particular conditions studied.

Jan 1, 1952

The selective placement of coal stripmine overburden is examined. Physical and chemical properties of spoil detrimental to revegetation and groundwater are detailed. The United States is divided into regions or similar problems. Five mining methods already used in the industry, that are capable of selectively handling waste are examined in detail. Technical and economic comparisons are made for the systems when applied to realistic mine settings. The same analysis is conducted for five novel methods capable of selectively handling waste. Comparisons are made between novel and existing methods. Suggestions for new and modified equipment are outlined. Recommendations for further research are provided. This volume contains all Appendices to the report.

Jan 1, 1981

By G. L. Oldright

This paper is the second of a series that is to appear on smelting in the lead blast furnace. The objects of this investigation are to determine the conditions obtaining within the blast furnace by direct experimentation, and to correlate the behavior of the furnace at various times with the main factors governing the operation of the blast furnace, and metallurgical losses. The writers wish to express their appreciation to the management of the International Smelting Company at Tooele. Utah, for their kind cooperation which made possible the assembling of these data.

Jan 1, 1929

By G. B. Shea

Among the many engineering problems directly related to conservation in the petroleum industry, that of crude-oil emulsions continues to be important. Emulsions of water and oil always have constituted one of the most serious forms of waste in the oil fields, and the necessity of dehydrating emulsified crude petroleum to obtain marketable or pipe-line oil confronts operators in many fields with a major operating problem. In 1926 the Bureau of Mines published a comprehensive treatise s on oil-field emulsions dealing with field conditions, practical methods of dehydration, and physicochemical characteristics of the formation and resolution of emulsions. Although this bulletin is still available and may be obtained from the Superintendent of Documents, Washington, D. C., and although its contents are a valuable reference on the subject of emulsions, knowledge regarding the physical properties of emulsions and the phenomena of dehydration has increased greatly within the last decade. With the information gained through continued scientific research, substantial improvements have been made in the art of resolving petroleum emulsions. Moreover, in recent years there has been a growing realization of the importance of emulsion-preventive measures that has led to more critical examination of the causes of emulsions and methods of eliminating or at least reducing the degree of emulsification. Conditions causing agitation and commingling of oil and water and the formation of "cut oil" often are within the control of the producer, thereby making it possible to utilize preventive or remedial measures by which emulsification may be minimized or avoided. In fact, many companies have materially reduced their treating costs as a result of careful studies in emulsion prevention and proper handling of "wet" production. Of course, in many instances preventive measures or the correction of conditions causing emulsification cannot be achieved practically or economically, and the emulsions that form must be treated regardless of the care exercised or the money spent in attempting to prevent their formation.

Jan 1, 1939

By L. J. E. Hofer

This Bureau of Mines study, part of a broad program of research in air pollution related to minerals, was conducted to determine the nature and extent of the poisoning of catalysts when used to remove certain air pollutants from exhaust gases. The poisoning examined in this investigation occurs when leaded gasoline is used as a fuel for automotive engines. This research was conducted in cooperation with the Public Health Service. The smog in the Los Angeles area is attributed to the effect of radiant energy on the mixture of hydrocarbons and nitrogen oxides found in the atmosphere there. A large portion of the hydrocarbons is believed to originate in the exhaust gases of automobiles. To prevent the escape of these hydrocarbons into the atmosphere catalytic mufflers have been proposed. In principle, these are simple and nonmechanical, consisting of a vessel charged with a catalyst capable of destroying the exhaust hydrocarbons by catalyzing their oxidation. However, these catalysts are severely affected by the particulate matter, mainly in the form of lead sulfate (PbS04), lead oxysulfate (PbS04.Pb0), and Lead chlorobromide (Pb(Cl,Br)2), contained in the exhaust gas. Deposition of lead on the catalyst as PbS04, PbS04, PbS0, and Pb(Cl,Br)2 restricts catalytic activity. As a result,after 20,000 miles of operation the temperature necessary to achieve 50-percent conversion of isopentane in a mixture of 0.2 percent isopentane, 2 percent carbon monoxide and 4 percent oxygen, and the balance nitrogen at 10,000 hourly space velocity has risen from 400° C. to 500° C. even with a catalyst taken from the exit portion of the catalyst bed. The rest of the catalyst was more severely affected. Therefore, it would appear that operation for 20,000 miles is near the limit for a catalyst.

Jan 1, 1963

By Steven R. Munts

The U.S. Bureau of Mines investigated mines, prospects, and mineralized areas in the South Providence Wilderness Study Area (WSA) in 1982. No mines are currently operating in the WSA, however, the Golden Gift Mine in the southeastern part of the WSA produced $6,800 1/ worth of gold and silver and five mines adjacent to the east boundary of the WSA had a total production of about $3,500,000 1/ in gold, silver, lead, and copper. There is no recorded placer gold production. Over 350 lode and placer mining claims are in and immediately adjacent to the WSA. Of these, 74 were actively held (1982) and at least one area, which is partly within the northeast portion of the WSA, was being actively explored by private industry in 1982. Adjacent to the southeastern border of the WSA the Big Horn Mine contains an estimated 200,000 tons of indicated and inferred marginal reserves averaging 0.25 oz/ton gold; and the Hidden Hill Mine has 550 tons of subeconomic resources averaging 0.60 oz/ton gold. An additional 11,000 tons of marginally economic gold-bearing dump reserves average 0.17 oz/ton gold at the Bighorn, Hidden Hill, and the Buena Vista Mines and the Midas Touch Prospect. Sample analyses indicate eight mines and prospects in, and five adjacent to the WSA may have additional gold-silver-lead-copper vein-type resources. Five of these prospect areas may have a disseminated gold resource and one may have gold resources in a skarn. One prospect may have a porphyry-type copper-molybdenum resource. Although gold placer claims were filed sporadically throughout the WSA, none appears to have placer gold resources. Likelihood for mining is greatest at the Big Horn Mine; if a mill is built there, it could process Big Horn Mine ore, ore from the Hidden Hill Mine, and gold-bearing dumps at the Big Horn, Hidden Hill, and Buena Vista Mines and the Midas Touch Prospect. All of these resources are adjacent to the WSA; however, their development would increase likelihood for development of resources in the WSA. Two major fault zones (the Hidden Hill, and the Big Horn) appear to have controlled the mineralization at many of the prospects and mines. All of the prospects or mines with vein-type occurrences and resources are on or adjacent to one of these fault zones. Veins throughout the eastern half of the WSA contain various amounts of gold, silver, and copper; only veins near the Big Horn Mine and in the northeastern corner of the WSA contain lead. Some veins are as thick as 6 ft, are traceable intermittently for over 2 mi along strike, are sporadically mineralized, are encased in prophylitic, argillic, and phyllic altered host rock, contain pyrite, chalcopyrite, galena, specularite, barite, or fluorite, and display multiple stages of quartz veining and (or) brecciation. Sample analyses at five prospects (map nos. 3, 18, 23, 24, and 31) indicate they may have disseminated gold resources. To date no oil or gas has been discovered within the WSA. However, some oil and gas leases are currently (August 1982) held within this study area.

Jan 1, 1984

By Fred S. Karn

Inhibitors are used in coal mines as a precaution against accidental dust explosions. Although rock dust is the usual inhibitor many others have been tested. To facilitate testing a screening process using laser irradiation was proposed. The procedure includes irradiation of a coal-dust mixture followed by mass-spectrometric analysis of the evolved gases and an evaluation of the flammability characteristics of the gases. Carbonate-type inhibitors decreased the percentage of combustibles in the gases generated and inhibitors like NaCI (thermally stable salts) decreased the total gas generated. A suitable test procedure did not result from the investigation, demonstrating the inadequacy of fast heating, non-combustive techniques in rating inhibitors of coal dust explosions.

Jan 1, 1973

By K. K. Kershner

The purpose of this investigation was to develop methods, on a laboratory scale, for recovering tin from Bolivian metallurgical slimes. Petrographic and chemical analyses were made of slime ore fractions from several well-known tin operations. High percentages of the total tin were volatilized as chlorides at temperatures below 600° C. Under optimum conditions reaction rates were relatively rapid, and the chloridizing reaction approached completion. Owing to the low temperatures involved and the high yields of tin, the process was considered to have possibilities for treating Bolivian slimes on a commercial basis. ACKNOWLEDGMENTS Appreciation is hereby extended to the Patino Mines and Enterprises, Inc., of Bolivia, for supplying slimed tin ores that were used in the experimental work. This company has since been nationalized.

Jan 1, 1959

By Richard L. Fowler

[Study and development of sensing techniques and sensors were performed to aid shuttle car drivers in detecting, obstacles and in guiding the car along the face haulage route. Microwave, acoustic, and optical sensing techniques were considered as part of the feasibility study for obstacle detection. Various guidance techniques, including wire-following and rib-ranging were investigated. Active optical sensing was selected for obstacle detection to obtain the bear overage and sharp angular cutoff characteristics required within the packaging limitations defined by the shuttle car configuration. Rib-ranging guidance was selected to achieve completely self-contained shuttle car system which responds to the mine geometry without need for wires, stripes, or other path defining devices. Extensive hybrid computer simulation runs were performed to valuate various guidance techniques during the feasibility study. Subsequent simulation rues were performed to establish parameter values for the rib-ranging guidance system. The obstacle detection and guidance system was designed, fabricated and installed on a standard shuttle car. The system satisfied all applicable permissibility requirements of Schedule 2G. An experimental permit was issued to Bendix for operation in an underground coal mine. System evaluation tests were performed first above ground at the Bendix Research Laboratories. The simulation model was validated by these runs. Final testing wan performed underground in an operating mine with an experienced shuttle car driver. All sensors successfully demonstrated Chi predicted performance capability during underground face haulage tests. Dust did not Impair system performance and lens cleaning was not required during working shifts. Further development is required to achieve the desired obstacle detection performance Closed loop steering control with manual override is recommended o: mended for the lateral guidance e system. The guidance system should be an invaluable aid to low-coal shuttle car drivers where continuous mining machines are utilized.]

Jan 1, 1973