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By W. L. Dare

This information circular is one of a series, published by the Federal Bureau of Mines, on methods and costs of mining uranium ore on the Colorado Plateau. This report describes the relatively small-scale operations of the Salt Wash miner: The mining method followed, the equipment used, and the production costs. It describes 10 lease-operated mines of Union Carbide: Nuclear Co. that are typical of Salt Wash operations on the plateau. These mines lie within the Uravan mineral belt3/ and arc in the Gateway, Bull Canyon, and Uravan mining districts. (See fig. 1.) Generally the ore bodies occur as irregular, discontinuous layers of ore minerals within sandstone beds in the Salt Wash member of the Jurassic Morrison formation. The ore bodies sometimes occur as rolls, pod associat with carbonaceous trash, or tabular masses. Their size and erratic distribution preclude the use of a prearranged and uniform stoping system. The mining method is simply to follow the ore and leave open scopes behind.

Jan 1, 1959

By W. J. Fene

"The prevalence of accidents in the coal-mining industry has prompted a study of the workmen's compensation laws of the various States and the statistics of accident costs, for the purpose of explaining to operators how the compensation laws are regulated and to show the cost of accidents.The subject of compensation laws and accident costs is by no means new, but the prevalence of coal-mine accidents would indicate that the mine operator in general is not thoroughly conversant with their importance. Unquestionably, compensation laws are a large factor in promoting accident prevention, and it is believed that a greater measure of success would be accomplished in preventing accidents if all mine operators were fully aware of their important bearing on the cost of production.Many operators seem to be indifferent to accident occurrence; possibly they do not real¬ize the seriousness of the accident hazards that exist in their mines, even after the hazards are brought to their attention. There is no question that material financial advantages are to be gained by the prevention of accidents and it would appear that when these advantages are thoroughly understood, operators would be anxious to eliminate, insofar as is feasible, conditions likely to cause accidents.The unsettled state of the mineral industry and the irregular operation of mines during the past several years has probably been an important factor in influencing the apparently indifferent attitude of the operator. The chaotic conditions in the mining industry and especially in coal mining are unquestionably a factor that tends to increase accidents, just as mine idleness increases roof hazards and results in deterioration in mechanical, electrical, and haulage equipment, and promotes disorganization of the personnel. During such times greater efforts should be exerted toward the prevention of accidents because of these increased hazards and of the financial advantages brought about by the various savings to be effected when mine accidents are held to a minimum.This report on accidents in the coal mines of Pennsylvania was made possible largely through the cooperation of William J. Maguire, director, Bureau of Statistics, Pennsylvania Department of Labor and Industry, and Rush N. Hosier, superintendent, Coal Mine Section, Pennsylvania Compensation Rating and Inspection Bureau, who made available their records and extended much assistance and numerous courtesies during this study."

May 1, 1932

A complete list of permissible mining equipment, rescue apparatus and gas masks tested. Prior to Jan. 1, 1929, w s published in Bureau of mines Information Circular 60972. The present list includes practically all equipment tested and. approved by the Bureau, up to and including July 1, 1929. It covers electric air compressors, coal drills, mining machines, loading machines, conveyors, mine pumps, room hoists,, mine telephones, rock-dusting machines, switches, electric cap lamps, flame safety lamps, electric hand and trip lamps, flash lamps, methane indicators and detectors, blasting units, storage battery locomotives, tandem locomotives, power trucks, concrete mixers, self-contained oxygen breathing apparatus and gas masks. The system under which these devices were tested permits the manufacturer, after his equipment has passed certain tests prescribed by the Bureau of Mines, to mark his equipment with a seal showing hat it has been "approved" by the Bureau. These tests are designs to insure that the equipment has the minimum requirements for safety in use. The only object of the Bureau in making such tests and publishing lists of permissible equipment is to safeguard the lives of workers and to help lessen the hazards of mining.

Jan 1, 1929

By David C. Oyler, Paul W. Jeran, William P. Diamond

The Bureau of Mines is cooperating with the U.S. Department of Energy in a directional degasification project at the Emerald mine near Waynesburg, Pa. This project is designed to combine the highly successful underground horizontal degasification technology with surface drilling methods. The objective of this program is to demonstrate that directional drilling can be used as a technique for degasifying coalbeds ahead of mining to reduce the hazards of methane-air explosions in coal mines. The directional hole at the Emerald mine is designed to start vertically and enter the Pittsburgh coalbed horizontally. A 3-inch-pilot hole entered the Pittsburgh coalbecl at a vertical depth of 999 feet, The hole will be reamed to 8-3/4 inches in diameter, and 5-1/2-inch casing will be cemented in place. Three individual 3-inch-diameter, 3,000-foot horizontal gas collection holes will be drilled into the coalbed in a “bird foot” pattern. A corehole and vertical dewatering hole have been completed at the anticipated coalbed intercept. The dewatering hole was drilled to130 feet below the Pittsburgh coalbed, a depth of 900 feet, and 880 feet of 7-inch-OD casing was cemented in place. Seven vertical holes for monitoring the extent and progress of degasification have been drilled within the horizontal drilling area.

Jan 1, 1979

By K. P. V. Lei

The Bureau of Mines as part of its research effort to minimize the generation of hydrometallurgical waste, investigated a sodium sulfide leaching-electrolysis procedure for treating hydrometallurgical residues for elemental sulfur and base-metals recovery. Research was conducted on a leaching residue from a lead concentrate. The following procedure was developed. 1. The elemental sulfur was dissolved as polysulfide with an Na2S solution. 2. The resultant metal sulfide bearing residue was oxidatively acid leached in a cationic membrane electrolysis cell; the metals were solu¬bilized at the anode, and a base was generated at the cathode. 3. The elemental sulfur was recovered from the polysulfide solution by neutralizing with the acid in the anolyte. Byproducts of the neutralization were H2S and a sodium salt solution. 4. Sodium sulfide was regenerated by reacting the H2S byproduct with the base in the catholyte. 5. Lead as PbCL2 was recovered from the anode residue by brine leaching, and the other metals were recovered from the sodium salt solution as metal sulfides. 6. The barren filtrate from the metal sulfide precipitation constituted the recycled electrolyte. Ninety-eight percent of the elemental sulfur, 98 pct of the lead, and up to 80 pct of other accessory metals were recovered from a residue obtained from the FeCl3-NaCl leaching of a lead concentrate.

Jan 1, 1982

By Dennis R. Dolinar, Eric R. Bauer

Skin failures of roof and rib in underground coal mines continue to be a significant safety hazard for mineworkers. Skin failures do not usually involve failure of the support systems, but result from rock or coal spalling from between the support elements. For instance, in 1997 more than 800 miners were injured by roof and rib falls, of which 98% were the result of skin failures [Bauer et al. 1999]. Also, nearly 80% of the roof and rib failure injuries occurred at or near the working faces in development sections. The face area is a zone where the potential for skin failure accidents and injuries and for roof and rib failures is high because of mining activity, ground readjustment due to changing stress conditions, and the higher exposure of mine workers. In addition, failures occur where the roof and rib are unsupported. This paper reviews the roof and rib accident statistics resulting from skin failure, and highlights the incidences by type, numbers and percentage, in-mine location, supported and unsupported roof, and worker activity at the time of injury. Also discussed are the causes of roof and rib skin failures, current and improved support methods and materials for skin surface control, and machine design modifications for improved roof bolter operator protection. It also reviews the historical literature on skin failures and control methods.

Jan 10, 2000

"It is evident that the incidence of coal worker's pneumoconiosis (CWP) or black lung disease varies in different coal producing regions of the United States. Many people have hypothesized about the reasons for the differing occurrences. Because underground coal mining involves many mining methods under changing geological conditions, several factors may be involved in contracting CWP such as: the amount of quartz in the respirable dust, the trace elements in the respirable dust, the rank of the coal that produced the respirable dust (bituminous, anthracite), the amount and size of respirable dust, etc.Recognizing the uniqueness of underground coal mining and CWP, research investigations involving seam characteristics, mining system and worker position are being conducted in the center to establish standard procedures for characterizing some coal properties that may be involved in workers contracting CWP. This has been accomplished by the in-mine sampling of airborne dust at various worker locations and mining system configuration and by performing laboratory analyses of mined material (coal and rock) taken from the mines. (FIGURE 49 and 50)The investigations includes a method of classifying coal seams according to their potential to generate respirable dust. It includes statistical analyses of the size and locational variations of the elemental compositions of respirable coal mine dust in operating underground mines from seams located in the eastern, midwestern, and western United States, and is currently completing research which is investigating the relationship between the elemental compositions of respirable dust sampled near a continuous-mining machine and a laboratory-produced respirable dust."

Nov 1, 1988

By Brian Kenner, Peter Swanson, Todd Krahenbuhl

NIOSH has developed an automated PC-based seismic event (induced earthquake) monitoring system for use in mine ground control studies. The distribution and coordination of data acquisition and processing functions across a local area network is a central feature of the system. Mine-wide installations utilize multiple, autonomous seismic networks located both underground and on the surface. Seismic event locations, magnitude estimates, and other processed data are distributed for display and analysis on network nodes both underground and in the offices of mine engineers and managers. This paper describes the system’s design philosophy, hardware and software components, examples of installations, and a few observational results.

By F. W. Hoertel

Near-optimum parameters were determined by the Bureau of Mines for vapor deposition of rhenium on heated copper substrates by hydrogen reduction of rhenium hexafluoride (ReF6). High-purity deposits of nearly 90-percent theo¬retical density were obtained with the reaction chamber at 250° C, with an H2 to ReF6 volume ratio of 25 to 1, and with an ReF6 flow rate of 5 grams per hour. Some rhenium deposited as a loose, black powder. When the established near-optimum parameters were carefully followed, this could be minimized but never completely avoided. Varying the reaction chamber pressure, both above and below atmospheric, yielded excessive quantities of rhenium powder. Deposition efficiencies, based on only the coherent metal, ranged between 70 and 75 percent. Massive deposits contained only spectrographic traces of impurities. The average microhardness (Knoop, 100-gram load) of vapor-deposited rhenium was 907. Limited research on the deposition of rhenium-tungsten alloys by reduction of the mixed hexafluorides produced deposits in which linear composition gradients were pronounced; this nonhomogeneity was attributed to the wide variation in optimum hydrogen-reduction temperatures of the two hexafluorides (250° C for ReF6 and 550° C for WF6). Using deposition temperatures between 250° and 550° C did not eliminate the composition variations.

Jan 1, 1967

By F. C. Gregory

"Introduction.The third annual mine-rescue maneuvers of the Globe-Miami District First Aid and Mine Rescue Association were held at Globe, Ariz., on November 5 and 6, 1923. The first demonstration was held in October 1922, and the results** from that experiment, both in the practical training and the interest aroused in the apparatus men, were so much more satisfactory than those from the ordinary smoke-chamber training, that Orr Woodburn, director of the Association, decided to hold similar maneuvers at frequent intervals. The second test was held on March 21-22, 1923, in connection with the meeting of the Southwest Mining Section of the National Safety Council at Globe.Place and Organization.The recent maneuvers were held in the same mine and conducted in the same general manner as the first, and the points of interest not brought out previously are described below. By studying the accompanying map the movement of the teams can be better understood.Thirty-three apparatus men were out on the first day and thirty-two on the second day, a total of forty-three men being trained.Mr. Woodburn was aided in directing the work by his two assistants from the mine-rescue station, two local safety engineers, and an engineer from the Bureau of Mines. Local mine superintendents and the State deputy mine inspector were interested spectators."

Jan 1, 1924

By Thomas V. Falkie, R. Venkataramani

Table

Jan 1, 1972

By A. W. Fahrenwald

The logic leading to the development of the experiments in this paper already has been stated in Part I,3 but is briefly as follows: The results of the batch-grind experiments in which time of "grind" and fineness of finished product were the variables, strongly indicated (1) that batch grinding involving a single grind could not be operated under any condition to give maximum mill efficiency, (2) that the, sieve analysis of the feed charge in the mill materially affected the efficiency of the mill, and (3) that the percentage of finished product in the mill is a vital factor in ball-mill efficiency. A laboratory closed-circuit grind technic designed to simulate present closed-circuit grinding suggested itself, in which: a ball mill and a classifier constitute the grinding unit. The features of the closed-circuit grinding system are: (1) Short large diameter mills, (3) rapid flow of pulp through the mill, (3) continuous automatic removal of finished product from the system, and (4) high circulating loads. The high circulating load is a result if the short length of the Mill - that is, of the time the charge remains in the mill - and the small percentage of finished material produced during each circuit of the feed through the mill.

Jan 1, 1930

By W. D. Riley

The U.S. Department of the Interior, Bureau of Mines, has been conducting minerals recovery research in support of the nation's geothermal program since 1974. The Bureau's program of laboratory and field studies has focused on determining the materials of construction for geothermal resource recovery plants and an the recovery of mineral values from the geobrines. An analytical program has been conducted at the Avondale Research Center to determine the chemical constituents of some high- and low-salinity geobrines found in the Imperial, Valley of California. Data are reported for the early stages of brine production of femur geothermal wells--the low-salinity, medium-enthalpy brines from the East Mesa Known Geothermal Resource Area (KGRA), Mesa 6-1 and 6-2, and the high-salinity, high-enthalpy brine from the Salton Sea KGRA, Magmamax 1 and Woolsey 1. The reported results indicate the importance of the operating and engineering history, the operating parameters during sampling, and the method of sampling in order to evaluate the chemical analyses.

Jan 1, 1980

By A. Wahib Khair

"This article first describes the impact of respirable dust on the health of miners in underground coal mines in the United States of America. Second, it identifies the major sources of dust generation, namely cutting tools in the road headings. Two surveys associated with cutting tools were made to determine the useful life of these cutting tools, and to determine the effect of cutting tool wear on productivity of the continuous miners. Third, this article presents the results of a series of experiments carried out in the Rock Mechanics Laboratories at West Virginia University in order to study: 3.1 the effect of cutting tool rate of wear on respirable dust generation, 3.1.1 the effects of rock materials on tool wear and respirable dust generation, 3.1.2 the effect of cutting tool geometric parameters on respirable dust generation, and 3.1.3 the effect of tip materials used in the cutting tool on respirable dust generation. Recommendations in regard to cutting tool design are also presented in this paper.Silica and coal dust are the two major elements affecting the health of underground miners. According to Lemen [1] approximately 1,500 men died due to breathing in silica dust in 1936 while tunneling through a mountain of mostly silica, near the town of Gauley Bridge, West Virginia. Coal dust resulting in lung diseases in one of the major health hazards in underground coal mines. The impact of black lung on miners, coal workers' pneumoconioisis (CWP), has ranged from 16,000 to 23,000 each year since 1982 [1].The trend for conventional mining to continuous machine cutting of coal, using more productive machinery, is inexorable. Intolerable level of dust generated at the face is an indication of inefficient coal/rock cutting by these machines. The federal goverment of the United States paid about 11.7 billion dollars in workmen's compensation to more than 470,000 miners with CWP [2]. Bieniawski and Zipf [3] reported that annual benefit payments were about 2 billion dollars. The enactment of the Health and Safety Act in 1969 in the United States triggered the initial investigation into coal cutting mechanisms and cutting tool designs.The surveys concerning the utilization of cutting bits and performance of continuous miners in underground coal mines were made in order to have first hand information about bit consumption and coal produ¬ction.Three types of used bits, commonly utilized cutting tools on continuous miners, were collected from different coal mines. The used bits were grouped into symmetrically and asymmetrically worn bits. Distribution analysis for weight loss and conical height loss was done. Details of the results are presented elsewhere [4], here the results are summarized briefly. The analysis shows that approximately 50% of the collected bits have worn asymmetrically, which shows that many bits do not rotate properly during cutting. Analysis of the distribution of bit wear showed that the degree of bit wear varied from one type to another and with mining conditions. On average, the weight loss of the used bits was 4% to 7% with a maximum of 31%. Correspondingly, the loss of the conical height was observed to vary between 11% and 23% with a maximum of 71%. Figure 1 shows typical data associated with some of the used bits."

Jan 1, 1998

By Harold J. Bennett

This report deals with the processing and marketing of iron and steal scrap in the intermountain States of Arizona, Colorado, New Mexico, Utah, and Wyoming and the northwestern Plains States of Nebraska, North Dakota, and South Dakota. The quantity and quality of iron and steel scrap consumed in both the steel mills and iron foundries in these States in 1964 were decided by (1) the type of facilities used to produce an end product; (2) the availability of a dependable source of iron and steel scrap at competitive prices; and (3) the, ratio of the cost of iron in iron ore to iron in scrap. In recent years the quantity of scrap used per ton of steel ingot produced has decreased. The major individual. consumers of iron and steel scrap were the steel mills in Arizona, Colorado, and Utah, foundries in Utah and Arizona, and copper leaching, operations in Arizona, New Mexico, and Utah. About 2 million tons of iron and steel scrap was used by the iron and steel industry in 1964. Although there has been a decline in the amount of scrap used per ton of steel ingot produced because of changes in steelmaking methods, there has been a slight increase in the overall quantity of scrap used because of the increase in ingot production. It is estimated that the scrap consumption in the steel industry will increase by 19 percent by 1980. In addition to the scrap consumed by the steel industry, 273,000 tons of ferrous scrap were used by copper-leaching operations. Thirty-one percent of the ferrous scrap used by the steel industry in 1964 was purchased from dealers and other sources. The CF&I Steel Corp. (formerly The Colorado Fuel and Iron Corp.) at Pueblo, Colo., complemented its blast- and open-hearth-furnace operations with basic-oxygen converters in 1962. The basic-oxygen and open-hearth furnaces were charged with 30 and 90 percent scrap, respectively. Future use of the open-hearths would probably be used to supplement ingot production requirements. Because it was more economical to use less scrap and a high molten-metal charge, the United States Steel Corp. at Geneva, Utah, which uses the open-hearth process to make steel, charges the furnaces with 25 to 35 percent scrap. The Allison Steel Manufacturing Co. at Tempe, Ariz., uses a 100 percent scrap charge in its electric furnace. Although it was estimated that there were 327,000 tons of various grades of motor vehicle scrap generated in 1963, no estimates were made concerning the total quantity and grade of scrap available in the area. Most of the scrap used in the steelmaking industry originated within the area. It was advantageous to sell scrap generated in eastern Nebraska, North Dakota, and South Dakota to markets in the Midwest because of freight costs.

Jan 1, 1967

By M. Beus, R. Iverson, A. Dreschler, V. Scott

This paper describes research to improve safety during transport of ore and waste in underground mines. Field tests are underway in mines in Idaho and Montana. Strains measured on structural support members in an ore pass provided information about total forces acting on the structure as material was dumped into it. Results show that measured static loads were considerably less than actual total weight of the material dumped and that dynamic loads were subject to many factors, such as effects of blasting to remove hang-ups. Comparisons of measurements and computer results using a particle flow code indicated that several difficulties remain before achieving realistic determinations and models of the dynamic effects of particle flow in ort: passes and impact loads on the gates. Impact loads were overestimated in computer analyses as compared to loads measured in field tests. An alternative design approach based on softening the chute and control gate assembly is being proposed.

By Zsuzsanna Zborovszky

Experimental study directed toward gaining improved understanding of the exact mechanisms causing ignition in the PTB breakflash. Investigation and comparison of tungsten and copper wires as to their ability to cause hot wire ignition. Evaluation of the importance of discharge duration in the ignition process. Study of the parameters influencing the duration of a discharge (minimum discharge voltage, purity of electrode materials, purity and properties of the gaseous atmosphere contaminations, deposits on the electrode surface).

Jan 1, 1976

By E. Shekarchi

The mineral industry of Afghanistan improved substantially in 1976 as asbestos production was begun and feasibility studies were made of possible copper and iron and steel industries. The remarkable event of the year was the introduction of Afghanistan's 7-year economic and social development plan which covered the years 2976-82. The 7-year plan established ambitious goals for a gross national product (GNP) annual growth rate of 6.3% during its duration. To achieve this target, large increases in expenditures for economic development were programed in virtually every sector of the economy. Foreign assistance, in particular, was expected to finance a large share of new development projects. The major components of the plan were the development of transportation (highways and railroads), oil and gas exploration, construction of a copper smelter to exploit the copper deposits near Kabul, and development of an iron and steel industry to exploit the rich iron ore deposits in the central part of the country. Exports during the plan period were to continue to be principally agriculture products and natural gas to the U.S.S.R.

Jan 1, 1980

By H. H. Schrenk, Carlton E. Brown

"INTRODUCTION The angle at which a hole is drilled has long been thought to affect the amount of dust disseminated into the air during wet drilling. The amount disseminated has been reported as increasing rapidly with the approach of the angle of the hole to the vertical (up) position. 4/ This has been explained commonly as being caused by a decrease in contact of water with the face of the drill hole; increase in amount of sludge dropping through the air; and increase in amount of sludge running down the drill steel and being thrown into the air by the rotation of the drill steel and by leakage of air from the front head of the drill.The steep up angles of the holes drilled are responsible, at least partly, for the higher dust concentrations found in such places as raises, compared with those at level faces, where most of the holes are drilled at angles farther from the vertical (up) position. The mining industry is coming to realize more and more the importance of the angle of the drill hole as a contributing cause of the high dust concentrations found in some raises. Much work is being done to counteract the effect of the angle of the drill hole on dust dissemination. The rate of rater flow through drill steels is being increased by the use of water tubes of larger diameter or by higher water pressures to obtain better contact between water and the face of the drill hole. Traps are being developed to catch the sludge from the drill hole and allow it to drain down through a special pipe before it drops through the air or runs down the drill steel. Drills that permit little or no air to leak from the front head along the drill steel are being designed and used. Care is being taken to prevent the exhaust from the drill dispersing the sludge into the air."

Feb 1, 1938

By Robert Howard

With the rapid depletion of the Peerless Coal Co.'s mine in Spring Canyon, it was necessary, if the company was to remain in the coal-producing business, to look to the development of a new property or to acquire a mine already developed. After careful investigation of several operating properties it was decided by the officials of the company to take over the lease on an undeveloped acreage held by a private party in Price Canyon, about 3 miles north of Castle Gate, Utah.

Jan 1, 1930