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By Gordon R. Sima, John L. Bennett, Roger L. King

Electric shocks are a serious problem in the mining environment. Because of extremely wide ranging use of electrically powered equipment in the mining industry, the hazard to personnel due to electrical shock and related injuries are not restricted to any single area but cover the entire spectrum of mining activity. Electrical accidents, resulting in personal injury, due to im- proper or complete lack of grounding of electrically operated mining machines, form a significant percentage of the overall electrical accident picture. The object of this paper is to describe methods of detection of unsafe electrical conditions with respect to the grounding of electrically operated mining equipment. It also includes a discussion of prototype instruments which effectively monitor the condition of the grounding safety devices currently in use on mining equipment and warn of dangerous conditions as soon as they appear. The paper is based on work accomplished under USBM Contract Number 50357115. The contract was initiated under the Pittsburgh Mining and Safety Research Center Program. It was administered under the technical direction of PM and SRC with Mr. Roger L. King as the Technical Project Officer. Mr. Daniel B. Dawkins was the Contract Administrator for the Bureau of Mines.

By C. R. Summers, J. N. Murphy

In response to the Coal Mine Health and Safety Act of 1969, mandatory noise standards have been developed that specify time-noise limits of mine personnel exposure. Most affected by elevated noise levels is the pneumatic roof bolter operator, both in terms of levels near or in excess of 115 dbA and in terms of length of exposure. Therefore, the principal emphasis of this Bureau of Mines report is on pneumatic drill noise control. It is not the intent of this report to suggest any drill redesign; instead, methods are suggested to reduce the noise level by complementing existing machines. An integral muffler system and a separate muffler system were tested in an attempt to lower pneurnaric drill noise levels. Pneumatic drills, when new, operate at about 115 dbA when drilling in sandstone. Using the drill muffler systems, it was possible to decrease the noise level of a 115 -dbA s rope drill to approximately 100 dbA.

Jan 1, 1974

By R. L. King, J. Cervik, A. A. Campoli

The Bureau of Mines performed laboratory experiments to evaluate the triboelectric effect of particulate-laden gas streams on polyethylene pipe at various velocity, humidity, dust-size, and dust-load conditions. Charges in excess of 10 kV were produced on the outside and inside surfaces of laboratory pipe samples, when exposed to 40 pct relative humidity (RH) gas stream containing coal dust. However, no charges were produced in laboratory tests that duplicated the over 75 pct RH and dust-free gas streams found in working underground pipelines. Bare cop- per wire, which is wound around the polyethylene pipe in a 1-ft (31-cm) spacing and grounded, eliminated the charge on the outside surface of the pipe, but not on the inside of the pipe surface,

Jan 1, 1986

By Dana T. Updyke

The objective of this project was to develop technical data and evaluate performance and utility of leaky feeder communications systems currently used in North American underground mines. The desired information was obtained principally through on-site surveys. Altogether, six of the seven mining companies known to be using leafy feeder communications were visited. This report covers the findings of these surveys. In addition, the report provides a brief background summary of mine communications, a technical discussion of leaky feeder systems, and conclusions and recommendations based on the results of the survey.

Jan 1, 1980

By J. W. Jensen

EXTENSIVE research and development was performed on the manganese-copper vibration-damping alloys to determine the relationship between the properties of the alloys and variations in composition, fabrication, Mid heat treatment. Mn-Cu alloys with unusually high specific damping capacity, 20 to 25 percent at a stress of 5,000 psi, have also the following useful properties: Tensile strength, 90,000 to 110,000 psi; yield strong, 60,000 to psi; elongation, 20 to 25 percent; hardness, 90 Rockwell B; and fatigue limit at, 28,000 to 30,000 psi. Both standard and special methods of testing were employed to obtain data on strength, modulus, hardness, resistivity, dilatation, micro-structure, crystal lattice, and damping capacity. The extensive tabular and graphical data on these properties are presented for alloys containing 50 to 85 percent as quenched d solution) and after various aging treatments. Expansion coefficients for all Mn-Cu solid solutions are graphed and a dilatometer study of contraction during aging is reported. Although high damping capacity is associated with aging to precipitate a-Mn from solid solution, with a cubic-tetragonal transformation and with the occurrence of antiferromagnetic ordering in Mn-Cu alloys, a tenable theory of the damping mechanism has not been reached.

Jan 1, 1965

By Wing G. Agnew, John A. Johnson

"INTRODUCTION This paper is one of a series being published by the Bureau of Mines pertaining to an investigation on the use of stemming in metal mines now being conducted at the Mount Weather Testing Adit. Its purpose is to compare the amount of dust and gases produced as a result of blasting charges of dynamite (1) in drill holes, (2) in bombs, and (3) in mud-cap or adobe shots.ACKNOWLEDGMENTSValuable assistance and advice on stemming were given by members of the staff at the Bureau of Mines, as acknowledged in previous publications. 4/TEST PROCEDUREThe results used for comparison in this report are from dust and gas samples taken after blasting (1) four regular test rounds with no stemming, (2) five bomb shots, and (3) two mud-cap or adobe shots.The four rounds were the standard 26-hole test rounds designed to break 4 feet of rock. The procedure for drilling and blasting these rounds is described in Report of Investigations 3509.Before the regular test rounds were blasted, about 1,200 bounds of fine rock was placed on the steel mucking sheets that covered the end of the adit track; the wails, hack, and floor of the adit were washed thoroughly; and the fine rock on the mucking sheets was completely wetted.Each of the 5 bomb shots consisted of 10 sticks of dynamite tied together and hung at midpoint of the adit, 8 feet from the fall."

Dec 1, 1942

By R. L. Rickel

The Bureau of Mines, as part of its minerals environmental technology research, conducted a study of mine waste tailings disposal. Part of the investigation evaluated the sand bed dewatering technique for disposal of alumina mini plant tailings as a means to increase consolidation rates and contain effluents. The technique employs a bed of sand resting on an impervious bottom. The tailings slurry is impounded over the sand layer and is dewatered through bottom drain piping. The study employed a single 10-ft-high, 6-in-diam, clear polyvinyl-chloride (PVC) column, and thickener wastes from the acid leaching of calcined kaolin clay. Results showed a consolidation rate of 41 in in 186 days for a total volume reduction of 37 pct. Sand bed dewatering was an efficient technique for solid consolidation and effluent containment when compared with data obtained from other dewatering studies.

Jan 1, 1982

By J. L. Eakin

The works and opinions of experts on well stimulation and related problems are summarized in this paper. The material is devoted to stimulative work in petroleum and natural-gas wells exclusive of the generally applied pressure maintenance and secondary-recovery methods. Its purpose is to review a collection of recent and available material on well-stimulation methods and techniques. Each separate discussion is accompanied by a selected bibliography. An author index is included.

Jan 1, 1964

By J. L. Eakin

The works and opinions of experts on well stimulation and related problems are summarized in this paper. The material is devoted to stimulative work in petroleum and natural-gas wells exclusive of the generally applied pressure maintenance and secondary-recovery methods. Its purpose is to review a collection of recent and available material on well-stimulation methods and techniques. Each separate discussion is accompanied by a selected bibliography. An author index is included.

Jan 1, 1964

By Ronald W. Schaefer

This report describes operations at the Rosiclare Fluorspar Works of the Aluminum Co. of America at Rosiclare, Hardin County, Ill. The works include the Fairview mine, the fluorspar mill, and related facilities. The publication covers exploration, development, mining and milling practices, mine-drainage problems, and other activities and is presented as part of the Bureau of Mines series of publications on mining and milling practices in various parts of the United States. The Rosiclare fluorspar area, for its size, has been the largest producer of high-grade fluorspar in the United States and probably in the world. The vein system in this area is over 5 miles long and 1/2 mile wide, and ore has been found as deep as 900 ft.

Jan 1, 1961

By John R. McWilliams

This report is one of a series published by the Bureau of Mines describing methods and practices at various mines throughout the United States. A previous program, conducted from 1928 to 1939, was well received by the mining industry and technical institutions and provided much source material for engineering textbooks and technical handbooks. The stringent wartime demands on the mining industry, the rapidly changing postwar economic situation, and greatly accelerated technologic growth have combined to render many of the previous data obsolete. The objective of the present program is to assemble reliable technical information on mining methods and practices throughout the country and present it for the use of the mining industry, technical schools, textbook authors, and other interested persons. This report deals with the design and development of the Berkeley open- pit mine at Butte, Mont., owned and operated by The Anaconda Company. The Berkeley pit is but one facet of a well-organized and integrated copper-mining operation involving the entire Butte district. Vein-type mining, important for 75 years, is still in progress at depths from 600 feet to nearly 1 mile; on intermediate levels, low-grade ore left untouched by earlier vein-type mines is being extracted by block caving entire ore zones,3/ and secondarily enriched but lower grade near-surface portions of the same ore zones are being mined by open-pit operations (fig. 1). The Berkeley pit itself is named for the Berkeley mine, one of the old mines that extracted copper ore from high-grade veins in the area that now will be mined by open-pit methods.

Jan 1, 1959

By James L. Hendrix

The applicability of a rotating drum with an attached trommel as a flocculation dewatering device of Florida phosphatic claywastes was studied. Several experiments were conducted in order to determine the important fabrication and operating parameters. Results from the experiments indicated flint the dosage of polyethylene oxide required to form a satisfactory product cake could be reduced by using the rotary drum, which introduces less shear stress into the fluid than a constant stirred tank mixer. It was found that the length of the mixer was the most important parameter. Increased length increased the retention time the flocs stayed in the mixer without dewatering. Such increased time decreased the stability of the flocs. Through analysis of residence time distribution data it was found that the longer mixers approached plug flow characteristics. Other important parameters were trommel length and rotational speed. Mixers from 10 cm diameter to 35.6 cm diameter were tested with good results.

Jan 1, 1982

By G. L. Bloomsburg

This report describes work which was done to apply an existing finite element computer program UNSAT2 to the unsteady, unsaturated flow of water through waste shale piles. The work was done in three phases: 1. Verification of program through comparison with existing data. 2. Verification of program through simulation of flow from field seepage ponds at Rifle, Colorado. Considerable laboratory work was done in this phase to obtain capillary pressure-saturation-relative permeability data and hydraulic conductivity values for retorted shale. 3. Application of program to flow due to natural rainfall in a section through the Piceance Basin in Colorado, and a typical waste shale pile.

Jan 1, 1978

By J. H. East

"INTRODUCTION Diesel locomotives have been used successfully in underground mines of Europe for 18 years, and much has been written on the technical details of the design of these machines and the safeguards provided by the manufacturers. The actual conditions under which' the Diesel locomotives are used have not been publicized as well and consequently are not well-known. In 1945 the writer observed numerous Diesel locomotives working underground in coal and metal mines of several European countries and was favorably impressed with the practical approach to the safe use of this- type of equipment.Recent statistics showing the number of Diesel locomotives in use are not available now because of the World War, but the extent to which this type of mine locomotive was used immediately before the war is indicated by table 1, which classifies the number of locomotives used in several countries according to the type of power, such as compressed air, Diesel, and electric.Mining conditions observed by the writer in the European countries are very different from those in most coal-mining districts of the United States. The surface plants are larger and are permanently constructed of brick or concrete; numerous coal beds are worked through one shaft; the crosscut rock tunnels or levels, driven to intersect the coal beds, are lined with brick or concrete blocks where needed instead of timber; the coal beds dip more steeply and are not as thick as in most fields of the United States."

Sep 1, 1946

By R. L. Kidd, T. H. Miller

"INTRODUCTION This paper is the seventh of a series of yearly reviews started in 1921 and pre¬sents information gathered in a cooperative investigation undertaken by the United States Bureau of Mines and the University of Utah. It is the purpose of this report to make available flotation—reagent consumption data and other milling information in such a manner as to be of value to the milling industry and to the manufacturer of flotation reagents.These data have been compiled from a survey of about 300 concentration plants in the United States. Much additional information has been obtained from the various offices of the United States Bureau of Mines. Many of the plants covered in the survey made complete reports of their operations, but others were apparently unable to supply this information in sufficient detail to meet the requirements of this report. As a result, some sections of the report are more complete than others. In general, however, the mill reports were much more complete than in previous years, and for the first time it has been possible to calculate average mill recoveries in the treatment of certain classes of ores. As in the past, every effort has been made to conceal individual plant operations.ACKNOWLEDGMENTSIt is realized that the publication of this information is possible only through the assistance of the mill operators, and the authors wish to express their appreciation of this cooperation. Thanks are also due the various field offices of the United States Bureau of Mines, division of mineral statistics, for assistance in collecting this information."

Aug 1, 1931

By N. E. Hanna

The current list of permissible explosives includes 124 different brands. Fifteen of these are gelatinous, and the rest are the more commonly used granular ammonium nitrate type. Their rates of detonation range from 1,300 to 5,600 meters per second, and the weights of 1-1/4 x 8-inch cartridges range from 86 to 244 grams. The list of permissible blasting devices includes 1 Cobra, 2 Hydrox, and 9 Cardox models. All of these devices are based on discharge of high-pressure gas from a pressurized shell in a shothole. INTRODUCTION To be approved for use in underground coal mines in the United States, explosives and blasting devices must pass certain schedule tests prescribed by the Bureau of Mines. The explosives listed here were tested under Schedule 1-G,3 which has since been replaced by Schedule 1-H;4 the blasting devices were tested under Schedule 26A.5

Jan 1, 1962

Sixteen papers concerned with the technology and utilization of low-rank fossil fuels are presented as the proceedings of the 1973 lignite symposium. This symposium, the seventh in a series of biennial meetings, was cosponsored by the Bureau of Mines and the University of North Dakota.

Jan 1, 1974

By FRANKM. SEIBERT, G. G. Oberfell, GEORGEA. BURRELL

The Bureau of Mines is conducting a series of investigations with the common aim of minimizing the losses that occur in the mining and treatment of mineral substances. The results of the investi- gations are being published in reports of the bureau. This report treats of a method of preventing some of the waste of the natural gas incidental to oil mining. This method, the condensation of gasoline from natural gas, offers to the oil operator and others a profitable means of utilizing some of the oil-well gas now being wasted. The most desired constituent of crude oil is obtained, the production of oil is not hindered, and the gas, after the extraction of gasoline, can be returned to the leased area to drive pumps or into pipe lines for uses to which natural gas is ordinarily put, usually with its fuel value lessened only in slight degree. Publications already issued briefly discuss the subject. In this report the work is treated in greater detail, and the results of many additional tests are shown.

Jan 1, 1915

By Andrew B. Cecala

The Bureau of Mines conducted a brief laboratory study on the 10-mm diam Dorr-Oliver nylon cyclone to investigate (1) whether high wind speed (>300 ft/min), or sampler inlet orientation with respect to wind direction, can introduce errors when sampling respirable dust, and (2) whether any such errors can be reduced by using an inlet shield. Being preliminary in nature, the study was not structured to produce definitive results, but rather to discern likely trends and to indicate whether or not a more in-depth study of the problem is warranted. Photometric mass sensing measurements suggested that as the wind velocity increased, the cyclone sampling directly into the high-velocity airstream tended to oversample, relative to the cyclone sampling in a low-velocity airstream. Orientation of the sampler introduced measurable differences in sampling efficiency at higher wind velocities. A shield placed around the cyclone diminished the effects of wind velocity and sampler orientation on sampler performance. Results of this work offer sufficient evidence to substantiate the need for a more in-depth study.

Jan 1, 1983

By W. F. M. GOSS

For the purpose of procuring data that could be used in estimating the value of the briquetting process as applied to American fuels, the United States Geological Survey, in cooperation with other interests, began in 1904, at the Louisiana Purchase Exposition, certain experiments involving the production and use of bituminous-coal briquets. It installed at St. Louis, and later at Norfolk, machines for the manufacture of such briquets, and the output of these machines has been tested in locomotive service on several different railroads in comparison with natural fuels. An elaborate and carefully executed series of tests involving the use of natural coals and of briquets made from the same coal, previously crushed, was carried out on a locomotive mounted at the testing plant of the Pennsylvania Railroad Company at Altoona, Pa.; and some preliminary experiments involving the use of briquets in marine service were made in connection with one of the Government's torpedo boats. A description of these tests is presented herewith. The results sustain the following general conelusions: 1. The briquets made on the Government's machines have well withstood exposure to the weather. and have suffered but little deterioration from handling. 2. In all classes of service involved by the experiments, the use of briquets in the place of natural coal appears to have increased the evaporative efficiency of the boilers tested. 3. The smoke produced has in no test been more dense with the briquets than with coal; on the contrary, in most tests the smoke density is said to have been less when briquets were used. 4. The use of briquets increases the facility with which an even fire over the whole area of the grate may be maintained.

Jan 1, 1911