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By David E. Nicholson

The Bureau of Mines has constructed a special compression chamber for developing stress-strain relationships of mine backfill and simulating the high compressive ground pressures encountered in underground mines. A one-dimensional, or Earth-Pressure-at-Rest model is proposed for backfills subjected to these pressures. Results of the compression tests performed in the chamber indicate that reliable stress-strain relationships can be developed from these tests. The primary objective of the test series was to evaluate the effectiveness of compaction of common backfills in retarding ground closure. Analysis of the stress-strain data shows an eightfold reduction in relative strain in optimum well-graded, compacted backfills over poorly graded, loose backfill material. Analysis of the one-dimensional compression test data also indicates a significant retardation of transmitted stress in dense compacted samples of backfill and natural sands. Although not fully understood, a deformation mechanism is thought to occur at the intergranular contacts in cyclic fashion causing frictional heat loss and a reduction in transmitted stresses in the densely packed materials. The experimental values of transmitted stress are compared with theoretical values of effective stress calculated from the one-dimensional compression relationships developed by Hendron (4).3 These experimental values of transmitted stress compare very closely with the theoretical values of effective stress.

Jan 1, 1968

By R. W. Van Dolah

A premature detonation of an explosive charge occurred on January 30, 1961, at a face being prepared for blasting in the underground Jefferson Island Salt Mine, Diamond Crystal Salt Co., Jefferson Island, Iberia Parish, La. The accidental blast injured the powderman fatally; his helper was injured also, but recovered. The accident represents the first fatality reported to the Bureau of Mines in connection with the use of ammonium nitrate-fuel oil (AN-FO) blasting agents in underground mining in the United States. Representatives of the Bureau of Mines Explosives Research Laboratory, Pittsburgh, Pa., and field representatives of the Bureau's Health and Safety Activity conducted the investigation, upon request of the manufacturer of the ammonium nitrate being used and with concurrence by the mine management.

Jan 1, 1962

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 H. M. Lawrence

"The land-pebble district, the larger of the two producing areas of Florida, is situated in Polk County and in the eastern part of Hillsborough County. About 80 per cent at the phosphate rock produced in the United States in recent years has been mined from this area. The phosphate ores, locally termed matrix. are beds of sands and clays containing the phosphate pebbles, considered to be Pliocene in age, derived by marine action from underlying Miocene phosphatic marls, and are covered by practically barren sands and clays that have been deposited more recently. Open-pit mining is practiced; hydraulic mining, which has been intensively developed in this district, is used exclusively for mining the matrix and, by some companies for removing the overburden, although drag-line excavators have become established and are proving economical for stripping operations. From the pits the matrix is pumped to adjacent washing plants for beneficiation. The product of the washers. after drying, enters the world markets as Florida pebble phosphate.In this district recovery of the phosphate pebbles by the washing plants has not been particularly effective in the past. The screening, designed to effect a seperation at about 20 mesh (0.033 inches), has not been well controlled. Washer rejects discarded to the waste dumps have contained appreciable amounts of material analyzing above the minimum commercial grade - 66 per cent B.P.L. (bone phosphate of lime). Such losses of commercial fractions should be considered avoidable, and have been discussed at length in a previous paper.3"

Jul 1, 1930

By O. Q. Leone

Excellent metal quality, with lower power requirement, is attained in electrorefining titanium by using internal heating of the fused-salt bath. An internal heater provides more effective heat utilization, simplifies structural components in cell design, and prolongs cell life by eliminating direct application of heat to the cell container. This Bureau of Mines report covers one phase of the research in progress at the Electrometallurgical Experiment Station at Boulder City, Nev., for improving the techniques and lowering the total power requirement for electro-refining titanium metal.

Jan 1, 1959

By R. W. Stahl

The use of continuous mining machines has greatly minimized the necessity for blasting in coal mines, even during pillar recovery; however, explosives are still used to blast stumps. The use of improper blasting materials, improper procedures, or both has caused mine explosions and fires, with loss of life and property damage. Researchers and manufacturers are continuously improving explosives and blasting accessories; use of the more recently developed materials will make the blasting operation safer. Extreme caution is mandatory when blasting stumps, as the ignition of methane or coal dust may trigger an explosion or cause a fire. Since the blasting of stumps will no doubt continue, although often unnecessarily, this paper summarizes recent findings published by the Bureau of Mines and recommends safer methods.

Jan 1, 1962

By Raymond B. Ladoo

The uses for which ground talcs are suited closely depend upon their physical and chemical properties , but , in spite of this fact , little scientific investigation has been made in order to devise quick and accurate tests for the determination of these properties . The chemical properties of talc are inherent and may not be altered or modified except by selective mining or by chemical processes not practical in the present status of the industry . However , the determination of chemical properties is not so important , for most uses , as of physical properties , although sometimes certain chemical characteristics are perhaps unduly insisted upon by chemists in some industries . Physical properties are dependent both upon mineralogical characteristics and upon methods of grinding and sizing and may thus be partly changed or modified by changes in practice . There is so little known of the chemistry and physics of the various processes in which talc is used that the purchase and sale of talc is governed more by rule- of- thumb methods dependent upon individual opinion and often , prejudice , than by accurate , standard tests . This not only causes unwarranted price fluctuations , but injures both the producing and consuming industries by creating false ideas of the suitability of talc for various uses . It thus seems important that present tests be standardized and made uniform for the whole industry , and that new tests devised to fill the existing gaps .

Jul 1, 1920

By Sean Gallagher, John R. Bartels, Dean H. Ambrose

Remote operation of continuous miners has enhanced the health and safety of underground miners in many respects; however, numerous fatal and non-fatal continuous miner struck-by accidents have occurred when using remote controls. In an effort to prevent these injuries, NIOSH researchers at Pittsburgh Research Laboratory examined the workplace relationships between continuous miner operators and various tramming modes of the equipment using motion captured data, predicted operator response times, and field- of- view data to determine causes of operator-machine struck-by events in a virtual mine environment. Factors studied included machine speed, direction of escape, operator facing orientation relative to the machine, work posture, distance from machine, and operator anthropometry. Close proximity to the machine, high machine tramming speeds, a right-facing orientation and operator positioning near the tail all resulted in high risk of being struck. It is hoped that this data will provide an improved rationale for operator positioning for remotely operated continuous miners.

By William H. Pomroy, Shail J. Butani

"This Bureau of Mines publication presents a statistical analysis of official U.S. Mine Safety and Health Administration (MSHA) metal and nonmetal mine fire reports from 1950 through 1984, plus accounts of selected nonreportable fires (less than 30 min and no injury) and opinion data on fire hazards from mine safety directors. Fires were analyzed by time trends, ore type, ignition source, burning substance, location in mine, equipment involved, means of detection, duration, number of injuries and fatalities, mining method, and successful extinguishing agent. The leading ignition sources were electricity in underground fires and engine heat in reported surface fires. The most frequent burning substance was combustible liquids for all nonreportable fires, reported surface fires, and reported underground fires from 1978 to 1984. For underground fires reported prior to 1978, timber was the leading burning substance. Mobile equipment was the type most frequently involved in both underground and surface fires. Underground fires occurred most often in haulageway or drift areas, and reported surface fires occurred most often in plant and mill buildings, while most nonreportable surface fires occurred in other areas. The most common methods of extinguishment were water hose lines for reported fires and dry chemical handportable extinguishers for nonreportable fires. INTRODUCTIONIn support of the Bureau of Mines research on mine fire protection, two separate baseline studies on mine fire incidents have been prepared. The first study addressed coal mine fires. The results of that study are summarized in the Bureau's Information Circular 8830, ""A Statistical Analysis of Coal Mine Fire Incidents in the United States From 1950 to 1977."" This second report, addressing metal and nonmetal mine fires, is the companion to IC 8830. Together, these two reports provide a comprehensive, factual summary of the mining industry's fire experience.This report, like IC 8830, covers (1) MSHA fire incident reports, (2) records of nonreportable fires (less than 30 min and no injury), and (3) mine safety directors' opinions on fire hazards. The MSHA fire reports provide the most reliable, objective, and accurate historcial record of the major noncoal mine fires that occurred during the study period (1950 through 1984). However, MSHA fire reports alone understate the true magnitude of the fire problem because metal and nonmetal mines have been legally required to report fires to MSHA only since 1968. Although some fires were reported prior to 1968, doubtless a great many were not. Also, the reporting regulations that took effect in 1968 specify that only fires lasting 30 min or longer or involving an injury need to be reported. MSHA fire reports are thus limited in scope by MSHA's legal authority. In order to provide a more comprehensive data base, it was also necessary to gather and analyze mine company records of nonreportable fires."

Jan 1, 1986

By Thomas W. Camm

This study was done to evaluate the costs of various dumping operations at waste and spoil piles. It has been theorized that accidents associated with dumping operations might be reduced by short-dumping rather than edge-dumping, but many operators have been reluctant to use short-dumping because they believe it is not as cost effective as edge-dumping. To evaluate this perception, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health reviewed the costs of various dumping methods at waste and spoil piles. The study found that overall cost differences between the two methods were not significant in most cases. However, while overall cost differences between the two methods appear small, capital costs could be more significant when short-dumping if numerous dump sites are used concurrently. The choice of which method to use should be based on considerations of the safety of dozer and truck operators.

Jan 1, 2000

By Erie C. Donaldson

Gas-displacement tests were made in Berea Sandstone and Arbuckle Lime-stone cores to determine the relative permeabilities to gas, oil, and water for two-and three-phase dynamic systems. Three-phase relative permeabilities were obtained by displacing oil and water from the core with gas and measuring the flow rates of the three fluids simultaneously. It was found that relative permeabilities to fluids in a porous medium are affected by the saturation distributions of other fluids in the medium as well as by their own saturation distributions.

Jan 1, 1966

By G. R. Fitterer, E. A. Krockenberger, B. E. Sockman, R. B. Meneilly, J. F. Eckel, E. W. Marshall

"Steel manufacturers have noticed a decided tendency on the part of many of their customers to become more exacting in their steel specifications. Under these conditions, the steel must not only meet the specifications of physical properties (tensile strength, reduction of area, elongation, impact strength, grain size, normality, etc.) and the chemical analyses, but must also pass the inspection test of ""cleanliness.""By cleanliness is commonly meant the absence of oxide and sulphide inclusions. Other foreign particles such as furnace or ladle slag, ladle and runner brick, etc., must also be absent. The determination of cleanliness at present is usually made by microscopic inspection or macroetching.The rejection of steel for lack of cleanliness is increasing, out cleanliness is one of the most difficult requirements for the manufacturer to fill. The reason for this is that every steel inspector has a different conception of a. clean steel. A material which does not pass the examination of one inspector way be regarded as entirely satisfactory by the metallurgist of an¬other company. The cause of this confusion and disagreement concerning the definition of a clean or a dirty steel is simply that as yet no standardized procedure for the determination of impurities has been proposed and generally accepted, since many variables are encountered which interfere with the development of a satisfactory method. An idea of the complexity of this situation will be obtained from the following pages.A Survey of Proposed Analytical MethodsAlthough no analytical method has been accepted, many procedures have been proposed, as may be seen in Table 1. Therein are listed 16 of the better-known processes, pith references to the work of their originators, their mechanisms of determination, and their applicabilities. Among these is included the electrolytic method developed by one of the present authors, and some comparison between this and previously proposed procedures may be obtained by a study of the table. It appears that this new method Las many advantages over the others, and this paper presents a critical Study of its value."

May 1, 1933

By D. W. Boley

This report contains the results of an analysis of the Logan oilfield, Hocking County, Ohio, and predicts the recovery of oil from the Clinton sand by waterflooding. Core analyses, electrical and radioactivity well-survey logs, reservoir-fluid analysis, and geologic and production data were used for this study. Considered in the evaluation were the reservoir geometry, depth, lithology, continuity of the rock properties, fluid saturations, fluid characteristics, rock wettability, and relative permeability-fluid saturation relationships. The study indicates that a properly engineered waterflood should recover approximately 135 barrels per acre-foot of effective sand. The predicted recovery warrants the initiation of a pilot waterflood in this field.

Jan 1, 1965

By Robert H. Merrill

Several investigators have obtained solutions for the concentration of stress around circular, ovaloidal, elliptical, and rectangular holes in an elastic, isotropic, semiinfinite plate subjected to uniaxial and biaxial stress. These solutions are used to evaluate the changes in stress around openings immediately under the undercut normally used in conventional block caving operations. The evaluations are based on the assumption that a horizontal undercut removes most of the vertical component of a biaxial stress field. The location and magnitude of the significant changes in stress concentration around the opening are computed. Conditions under which the assumptions used in the evaluations may or may not be consistent with conditions around block caving mines are discussed, and examples of preferred opening shapes for a biaxial (hydrostatic) stress field are shown. This report is a summary of one phase of an investigation to establish design methods for the size and shape of mine openings used in block caving mining methods .

Jan 1, 1962

The following report summarizes the results of engineering feasibility studies whose purpose was to assess the probable efficiency, reliability, safety and cost of a number of possible methods for removal of radon gas from the ambient air in underground mines. Fourteen candidate techniques were evaluated. Seven of these were based on specific individual principles, and seven were based on combinations of these principles. The individual principles were as follows: 1. Activated charcoal 2. Organic fluids 3. Semipermeable membranes 4. Molecular sieves 4. Cryogenics 6. Chemical reaction 7. Centrifuge The combinations were: 8. Cryogenics and activated charcoal 9. Cryogenics and molecular sieves 10. Cryogenics and chemical reactions 11. Membrane filters and organic fluids 12. Membrane filters, cryogenics and activated charcoal 13. Membrane filters and chemical reactions 14. Silica and an Organic Fluid

Jan 1, 1975

By PAUL L. FISHER

This bibliography has been compiled by the Bureau in answer to many requests now being received for information on the briquetting coal and other carbons . In addition to publications issued by the Government in printed or mimeographed form, references are included to articles appearing in the technical press and in cooperative reports of work done jointly with states , colleges , and industries . References and patents are arranged in chronological order . Bureau of Mines bulletins , technical papers and Minerals Yearbooks are printed , and are obtainable from the Superintendent of Documents ,. Government Printing Office , Washington 25 , D. C. Reports of investigations , information circulars , and the directories and reports of the mineral industry surveys are published in mimeographed form and may be obtained without charge from the Publications Distribution Section , Bureau of Mines , 4800 Forbes Street , Pittsburgh 13 , Pa . Many Bureau of Mines publications , as well as bound copies of the foreign and American scientific and trade periodicals , may be consulted in technical , college , and large public libraries throughout the country. Dealers in new and second-hand books sometimes have copies of these reports for sale .

Jul 1, 1948

By Douglas F. Scott

Zinc, silver, copper, and tungsten are the principal minerals in Dardanelles RARE II area (No. 4982). Zinc with associated silver and copper occurs in a persistent shear zone in metasedimentary rocks and in a massive sulfide vein; tungsten occurs as disseminated scheelite in a tactite zone along a metasedimentary-intrusive rock contact. Since 1883, approximately 100 lode mining claims have been recorded, mainly it the eastern portion of area No. 4982 (fig. 1). Extensive workings on the Alhambra Prospect indicate past production; however, no records were found for the prospect. At the Alpine Mine, 500 tons of tungsten ore had been mined before 1943 (Hopson, 1943, p. 1) and possibly 1,000 tons of tungsten ore mined by 1947 (Benson, 194/, pp. 2).

Jan 1, 1982

By Robert H. Bedford

The Rogan-Mallery tin property is in the foothills on the south slope of the Tehachapi Mountains, Kern County, Calif. It was first visited by the senior author in August 1942, and exploration by means of trenching and diamond drilling began in May 1944 and was concluded in August of the same year. Cassiterite, associated with iron-rich gossan, occurs in a limestone roof pendant at places near or at its contact with the underlying granitic rocks. The cassiterite grain sizes range from 20 mesh to 150 mesh. Surface and diamond-drill samples showed tin ranging from traces up to 122.6 pounds per ton. Exploration by the Bureau of Mines included 2,100 cubic yards of trenching and the drilling of 11 diamond drill holes totaling 1,000 feet. Dana Hogan, president of the Rogan Petroleum Co. of Los Angeles, Calif.) brought these projects to the attention of the Bureau of Mines in July 1942, and the following month a Bureau engineer made a preliminary examination in company with Hillard Mallery, of 408 Ruby Street, Redondo Beach, Calif., the man who discovered them.

Jan 1, 1949

By Frank J. Wiebelt

The Mohawk lead-zinc mining in San Bernardino County, Calif., was examined by D. W. Butnor, an engineer or the Bureau of Mines, at the request of Dunton, Ray, and Greenwood, leaseholders. Current operations were on a marginal economic basis, and government aid was sought in an endeavor to outline ore reserves so that production might be maintained.

Jan 1, 1949

By A. C. Richardson

The mine of the Porter Coal Co. is located at the town of Porter in the northwestern part of Jefferson, County, Ala., about 20 miles west of Birmingham. The operations in this mine are confined to the middle and bottom benches of the Mary Lee bed. The coal from the Porter mine is handpicked and washed before being placed on the market. The handpicked lump coal and the washed egg and nut, coal are sold chiefly as domestic and steam-raising fuel. The coal finer than 1 inch is washed in 2-compartment jigs and utilized in the manufacture of metallurgical coke. The coal company has found that, when coal ranging in size from 1 to 0 inch is washed in jigs, a considerable amount of high-ash material finer than 3/16 inch remains in the washed coal. This paper gives the results of an investigation which was conducted for the purpose of determining the washing characteristics of the through 316-inch raw coal and the extent to which the ash might be reduced by means of coal-washing tables. This investigation has been made in connection with an. extensive study of the coal-washing problems now being conducted by the United States Bureau of Mines and the University of Alabama, with the cooperation of the coal-mining companies of the State.

Jan 1, 1933