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By Ernest L. Corp

First in a projected series on the use of flexible liners for support of underground mine openings, this report presents information obtained from an extensive review of the literature on this subject. It also includes results of some preliminary test work by the Bureau of Mines. Investigations thus far indicate that flexible liners offer numerous advantages over rigid-type sup-ports, By deforming in the direction of the applied stress, the stresses are redistributed from the liner to the surrounding material. The corresponding buildup of passive resistance in the direction of diametric extension causes an equalization of stresses around the liner, thereby enabling the liner to carry loads in a more efficient manner. However, additional experimental data are needed to establish design criteria that will permit maximum utilization of the flexible liner concept in mining. Testing of small-scale models, accompanied by measurement of free-field stresses in material surrounding the model, is recommended as the most suit-able approach to the problem. The experimental procedures necessary to such an approach are outlined in detail and a statistical design for the experiments is proposed. The report also describes a device developed by the Bureau for measuring free-field soil pressures to 1,000 psi and a technique for evaluating the response of the device.

Jan 1, 1967

By John Nagy

Dust explosion data obtained in laboratory studies by the Bureau of Mines are presented for activated carbon, asphalt, charcoal, carbon black, coal, coke, gilsonite, graphite, lignite, miscellaneous carbons, pitch, tunnel dust, and mixtures of these materials with other ingredients. The explosion hazard is shown to increase as the volatile content of the dusts increases.

Jan 1, 1965

By H. H. Schrenk, F. E. Griffith

"The increase in tunneling operations that requires working under pressures greater than that of ordinary atmosphere has raised the question of the use and possible limitations of respiratory protective devices under such unusual conditions. As little, if any, information is available, there is need for a comprehensive study of this subject before specific recommendations can be made. In the absence of such data it seems desirable to make a few preliminary observations regarding the problems associated with wearing respiratory protective devices under increased air pressures.Two distinct problems must be considered--the mechanics of the apparatus used under such conditions and the physiological effects of increased pressures on wearers of respiratory apparatus. This report is confined to the use of oxygen breathing-apparatus and gas masks under pressure.ACKNOWLEDGMENTSThe data presented were obtained at the Queens Midtown Tunnel under construction at the east end of 42d Street, New York City, during a study of compressed-air illness conducted by the Bureau of Mines in cooperation with the United States Public Health. Service and the New York City Tunnel Authority.Grateful acknowledgment for cooperation and the use of facilities is made to Dr. R. R. Sayers and his associates, particularly Dr. J. W. Crosson (who acted as observer during the oxygen breathing apparatus tests), of the Division of Industrial Hyiene, National Institute of Health; to the Port of New York Authority, through Dr. Edward Levy; end to the contractors, through Doctor Emery."

Jan 1, 1940

By W. N. Patterson

The three major objectives of this contract were (1) to survey underground diesel-powered mining machinery to determine noise exposure problems, (2) to recommend noise control techniques, and (3) to develop a technique for predicting underground sound levels from surface sound power measurements. The objectives were achieved. The contractor developed information on the severity of the noise problem caused by diesel engines underground and pinpointed the equipment causing the problems. He recommended a number of corrective techniques that can provide relief until long-term solutions are found. A procedure for predicting underground noise levels from above-ground measurements of the machine noise was found valid for several cases tested.

Jan 1, 1975

By Robert L. Lagace, Alfred G. Emslie

This report presents a mathematical model for the propagation of UHF radio waves in the large cross-section tunnels of a room and pillar limestone mine, and describes the analysis of a small amount of propagation data obtained in a limestone mine. The model and analysis is based on the waveguide mode theory developed earlier for the transmission of UHF waves in coal mine tunnels, with allowance for propagation losses due to refraction into the tunnel walls, to scattering by wall roughness, and to long range random tilt of the walls. Propagation around corners and through pillars is also examined based on a ray theory approach, together with the beneficial effects of placing reflectors at intersections to significantly reduce corner losses. The theory is found to be in fair agreement with the data; however, additional in-mine measurements are needed to provide a more conclusive test of the model.

Jan 1, 1979

By V. H. Gottschalk

Sponge iron is a product resulting from the reduction of an iron oxide below the temperature at which the product melts. Commercial grades usually contain 80 to 95 percent metallic iron, 2 to 5 percent unreduced iron oxide, and an amount of siliceous gangue material depending on the pur.ity of the are used for reduction. The reducing agent may be gaseous or solid, and a large variety of procedures have been proposed for bringing the reducing agent into reaction with the iron oxide. Of the proposed procedures, the one that has the distinction of having been in continuous commercial operation for the longest time, from 1911 to date, was developed at a ceramic plant in Hoeganaes, Sweden, and yields? a product that has an enviable reputation as furnace feed wherever special, high-quality steels are made.

Jan 1, 1948

By John J. Ginty

The objective of the work reported herein was to evaluate state-of-the-art repeaters used in wireless communications to determine their suitability for use in extending the range of portable and mobile communications in underground mine applications. The scope of the work included wireless repeaters in the frequency range from LF (500 kilohertz) up to the one giga-hertz range. These repeaters included not only single-channel repeaters, that is F1/F1 repeaters for short range simplex party line communications, but in addition, F1/F2 type repeaters currently commercially available in the HF, VHF and UHF bands.

Jan 1, 1975

By Miro Mihelich

The mines and prospects in the vicinity of Landlocked Bay, 25 miles southwest of Valdez, Alaska (fig. 1), were examined, mapped, and sampled in July and August 1955 as part of a comprehensive investigation by the Bureau of Mines of ore deposits adjacent to Prince William Sound. The purpose of the investigation is to establish and record the location, nature, extent, and metallurgical characteristics of copper and associated metallization in the Prince William Sound district and to indicate, if possible, those areas in which additional exploration and development may be justified. Of particular interest are the possibly numerous deposits of massive iron sulfides that were neglected during early mining operations. These deposits may constitute important reserves of sulfur and iron. At Landlocked Bay deposits of copper-bearing iron sulfide minerals have been mined or partly explored through mine workings, which are in a zone about 1 mile wide along the western side of a large overthrust fault known as the Landlock Overthrust. Eight of the principal mines along this zone were examined end sampled. Although only three of the mines have a recorded production of shipping-grade copper ore, all have deposits of copper-bearing iron sulfide minerals that are similar in occurrence. The deposits occur as lenticular masses and disseminations of chalcopyrite, pyrite, and pyrrhotite which replace crushed rock or fill cavities along shear zones in greenstones and in sedimentary rocks that are exposed between sea level and an altitude of 2,500 feet. These lenticular masses of sulfide minerals range in size from small pods to ore bodies that have been stoped to maximum widths of 9 feet, strike lengths up to 70 feet, and dip lengths as much as 350 feet. Where accessible for sampling,, the copper content of the deposits ranged from a few hundredths of a percent to over S percent; zinc, gold, and silver are present in negligible amounts. Flotation tests of a sample composited to represent typical mine-run ore indicate that 81 percent of the copper is recoverable in a product assaying 28 percent copper at a concentration ratio of 17.5 : 1. INTRODUCTION Statistical records indicate that approximately 110,000 tons of metallic copper (about 16 percent of total Alaskan production) was produced from mines adjacent to Prince William Sound during the 40-year period ended in 1938. Although the principal production was from a large-scale mining and milling operation on Latouche Island (Kennecott Copper Corp., Beatson mine), a substantial amount of the total copper was derived from direct-shipping ores selectively mined or hand-sorted from numerous other deposits in the district. No production has been made since 1938; many of the claims have long been abandoned, and mine workings are either caved or deteriorating rapidly.

Jan 1, 1957

By T. J. Ballard

Corundum is a natural alumina (A120 ) and is next to the diamond in hardness . Except for the gem varieties , it is used principally as an abrasive , chiefly in grinding , dressing , and polishing metals and optical glass . Natural corundum is preferred to artificial abrasives for certain specialized jobs . Most of the corundum ( excluding emery ) mined in the United States came from the Corundum Hill mine in North Carolina and the Laurel Creek mine in Georgia . The Corundum Hill mine provided over half of the domestic production of corundum prior to 1900. Since 1900 , the importation of foreign corundum and the manufacture of artificial abrasives caused the decline of corundum mining in the United States .

Mar 1, 1947

By Richard V. Ageton, Harry E. Tufft, E. A. Holbrook

When an underground excavation is made, the rock surrounding the sides and top of the opening is deprived of its natural support and tends to fall. Whenever caving takes place, the time and extent of the caving depend on the character and condition of the rock. In strong homogenous rock, such as solid granite, even a large chamber may stand indefinitely, whereas a soft material, such as clay or a loose material like unconsolidated sand, falls immediately if not supported. Weaknesses in the rocks induced by structural features, such as joints, :fissures, bedding and cleavage planes, and fractures produced by blasting, will cause the falling of insecure blocks or slabs unless means are provided to support these in place. In an unsupported mine opening, as a tunnel, the first slight settling or adjusting movement of the rocks (the "initial creep" or "set") is caused by the great weight of overlying material pressing down the rock masses above and around the roof and sides of the opening until they key together in roughly the form of an arch. The rock, after it has adjusted itself to this shape, becomes. selfsupporting. Timbering is necessa.ry in all mining only to support, therefore, those comparatively small blocks or pieces of rock which tend to loosen from the top and sides of the opening during or after the formation 'of the natural rock arch, and which lie between this natural rock arch and the opening. This statement, of course, has its limitations. For example; a layer of strong rock, like limestone, may act as a beam; then only the material under the limestone will need support. Timbering is not, as is commonly supposed by the layman, used to supp!ort the huge mass of rock between the back (roof) of an underground opening and the surface. It would be impossible to place enough timbers in a:ny underground opening to support such a mass. This fact is not'·perceived by all miners.

Jan 1, 1923

By Russel R. Bohn

The objectives of this study were to: (a) determine the state of the art for the control effectiveness of various chemical dust suppressants, (b) field test the effectiveness of the dust suppressants, and (c) develop technical guidelines for selecting and implementing cost effective tailings pond dust control programs. Chemical stabilizers evaluated under field conditions were: Coherax, Calcium Lignosulfonate, Nalco 656, 655, and Magnesium Chloride. Testing in the field utilized a portable field in-situ wind tunnel. The wind tunnel was placed on the tailings surface and simulated wind speeds of up to 80 mph were used to determine wind erosion threshold velocities. Emission rate testing was performed with the wind tunnel through the use of a real-time cascade impactor. A control cost effectiveness evaluation was performed to determine how efficient the chemical stabilizers were on a dollars expended per acre basis.

Jan 1, 1983

By J. H. Crary

This report summarizes the results of a one-year agreement for research on the electromagnetic environment in coal mines, which was conceived as the beginning of a long term cooperative program between ITS and the Bureau of Mines. The concepts on which it was originally based are a result of the report on mine rescue and survival by the Committee on Mine Rescue and Survival Techniques of the National Academy of Engineering, dated March 1970. This report drew particular attention to the need for improved communications during and following mine disasters. In particular, the outstanding problems identified were the location of, and communication with, trapped miners. Some tentative solutions, generally involving long-wave electromagnetic signals, were offered. Consideration of the problems of disaster location and communication soon leads to consideration of the communications techniques (or lack of them) for use under normal mining conditions. In particular, if a disaster communication and/or location system is to be readily available and operable under disaster conditions, it should also be usable during mining operations. In this way operators can become familiar enough with the system to operate it during disaster conditions, as well as provide a mechanism for regular testing.

Jan 1, 1972

By R. W. Stahl

Gas accumulation and dust suspension are the major safety hazards in coal stockpiling and reclaiming operations. This report presents a schedule of safety precautions and plant design features devised by the Bureau of Mines to reduce danger from these and other sources.

Jan 1, 1965

By D. E. Van Dillen

Seven configurations for panel entries of a longwall coal mine are compared and ranked according to structural stability. These entry configurations are analyzed using three-dimensional finite element modeling The models include large dimensions to minimize boundary effects, elastoplastic constitutive relations, and simulated excavation and construction of support systems. The stability criteria are formulated in a quantitative manner to facilitate the ranking of the entry configurations. These criteria are based on the expected volume of caved rock in the entry openings. The stability ranking is applied to the entry excavation phase, the headgate phase, and the tailate phase of the entry life cycle. Parametric variations are applied using two-dimensional finite element models to determine the sensitivity to changes in mining and design parameters.

Jan 1, 1981

By F. H. Gunnell, W. C. Dunham

"INTRODUCTION The Treasure Hill mines, situated in Dry Canyon, Ophir mining district, Tooele County, Utah, together with several other properties in the district, examined were examined by Frank L. Wideman, an engineer, the Bureau of Mines, in September 1942.In April 1945, development drilling was started on the Treasure Hill mines, which are operated under lease from the Madison Mines Co. The project was continued in 1946 and terminated in 1947.While the Bureau of Mines project was in progress, the Morgan and Fullion tunnel workings were surveyed by Bureau engineers.ACKNOWKEDGEMENTSIn 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, It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative perk, and prepares the final report. The Branch, O. C. Ralston, chief, analyzes samples and performs beneficiation tests. The work here described was under the direct supervision of Paul T. Allsman, chief, Salt Lake City Division, Mining Branch."

Jan 1, 1948

By William W. Odell

In Europe and in certain other foreign countries studies have been made, extending over a period of years, relating to the winning of oil from oil shale. More work has been done in these countries than in the United States, for the reason that a supply of natural petroleum has not been so generally available there as here. Information has been obtained relating to present practices in these foreign lands in the development of a shale-oil industry. It is realized that in the past there has been very little inducement to invest capital in shale-oil enterprise in the United State's because the supply of petroleum has been plentiful; however, the time possibly is not far distant when the utilization of oil shale may be cons¬idered a desirable and financially sound venture, as it may be necessary before long to augment our supply of oil with that recovered by processing shale. The data presented herein portrays at least some of the thoughts of those engaged in obtaining oil from oil, shale in Europe, and they depict some of the results thus far obtained as well as certain plans for further efforts to win oil from shale; it is hoped that those who undertake the development of a shale-treating industry in this country will find useful information in this report.

Jan 1, 1946

By H. B. Humphrey

WHEN THE BUREAU OF MINES was created in 1910, the organic act had as one of its main provisions the following: That it shall be the province of said bureau and its director, under the direction of the Secretary of the Interior, to make diligent investigation of the methods of mining, especially in relation to the safely of miners and the appliances best adapted to prevent accidents, the possible improvement of renditions under which mining operations are carried on, the treatment of ores and other mineral substances, the use of explosives and electricity, the prevention of accidents, and other inquiries and technologic investigations pertinent to said industries, and from tinge to time make such public reports of the work, investigations, and information obtained as the Secretary of said department may direct, with the recommendations of such bureau. The nationwide nature of the health and safety work of the Bureau of Mines has given its representatives an opportunity to study and report on matters pertaining to health and safety in mines and related operations from the time the Bureau was established to the present. Regular annual reports and numerous additional papers and reports have been published each year to place on record and to make available the information gathered. While the basic purpose of this bulletin is to describe health and safety reports for the period January 1947 through June 1955, a selected number of earlier publica¬tions that are believed pertinent for reference purposes are included.

Jan 1, 1956

By J. W. Thompson

AN ACT prescribing the mode of maintaining and defending possessory actions on lands belonging to the United States. The People, etc. SEC. 1. Any person now occupying and settled upon, or who may hereafter occupy and settle upon any of the public lands belonging to the United States, unoccupied, except upon lands containing mines of any of the precious metals, may commence and maintain any action for interference with, or injuries done to his possession of said land, against any person or persons so interfering with or injuring such land or such possession. SEC. 2. On the trial of any such cause, the possession or possessory right of the plaintiff shall be considered as extending to the boundaries embraced by the claim of such plaintiff, so as to enable him to have and maintain any action as aforesaid, without being compelled to prove an actual inclosure; provided, that such "claim" shall not exceed in any case one hundred and sixty acres of land. SEC. 3. Every such claim, to entitle the holder to maintain any action as aforesaid, shall be marked out, so that the boundaries thereof may be readily traced, and the extent of such "claim" easily known, and no person shall be entitled to maintain any such action for possession of, or injury to, any claim, unless he occupy the same, or shall have made improvements thereon to the value of $100. SEC. 4. A neglect to occupy or cultivate such "claim," for the period of three months, shall be considered such an abandonment as to preclude the claimant from maintaining any action as hereinbefore mentioned. Sec. 5. Any person or persons claiming the right of possession to land under this act shall have the right to defend said possession and the claim thereto, and all the rights and privileges given them by this act.

Jan 1, 1918

By R. W. Stahl

Gas accumulation and dust suspension are the major safety hazards in coal stockpiling and reclaiming operations. This report presents a schedule of safety precautions and plant design features devised by the Bureau of Mines to reduce danger from these and other sources.

Jan 1, 1965

By K. T. Menzies

Over 1500 literature citations related to diesel exhaust sampling and analysis were obtained as a result of both computer and manual searches of nine data bases. Abstracts and hard copies of relevant citations were reviewed and those considered appropriate for evaluation were included in a bibliography. Based on the literature collected, available sampling and analysis methods for the following diesel exhaust contaminants were evaluated: CO, CO2, NO, NO2, Hydrocarbons, Particulates, PNA, S04, Oxygenates Emphasis was given to both laboratory and field methods for these species. Methods were evaluated on the basis of sensitivity, selectivity, accuracy and reliability and a selected list of preferred methods was developed for each compound/ class. The selected methods were additionally evaluated through communication with current investigators. Sampling and analysis methods for all compounds except CO and CO2 were observed to have some unreliability. Recommendations were made for future research to develop, improve, and validate methods.

Jan 1, 1979