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By McHenry Mosier

This progress report on a national survey of the use of detachable bits in metal mines covers 10 mines. It presents comparative costs for drilling with conventional and detachable bits, describes the reconditioning of drill steel, and gives various data on rock drilling at these particular mines. Reports to follow will include similar data on drilling at other metal mines in the United States. ACKNOWLEDGMENTS This report is based on costs and data developed and furnished by the operators of the mines visited. The author is greatly indebted to the officials and staff members at these mines for their cooperation and assistance.

Jan 1, 1936

By D. Harrington

"Up to the last 10 or 15 years, responsibility for accidents in mines was generally, though not universally, placed upon the person or persons immediately involved. Present-day thought is rapidly veering toward holding the industry responsible for accidents, with ultimate payment of the bill by the consumer, if financial expenditure should be necessary. While it is undoubtedly correct in principle that responsibility for accidents in and around mines should be shouldered by the employer and while it is probable that as time passes the burden will become even more definitely than now that of the mining companies, on the other hand it is an undeniable fact that large numbers of accidents occur through acts of omission or of commission of some person, very frequently the victim of the accident being the offender.Out of about 3,000 persons killed every rear in our -mines and quarries, nearly half or approximately 1,500 of the fatalities are due to falls of overlying material or of persons, about 500 to haulage, about 350 to fires and explosions, about 125 to explosives, approximately the same number to electricity, and about 300 to various miscellaneous accidents.Generally the accidents from falls involve but one or two persons at a time, and the tendency is now as it always has been to charge the victim or possibly a coworker with the responsibility. Usually this sort of accident occurs at or near a working face (statistics indicate that about 80 per cent of fatalities from falls of roof or rib occur near the face), and as it is Generally agreed that it is the duty of the worker to keep his working place safe, the worker and especially the face worker is given the blame in case of accident."

Apr 1, 1930

By Joseph J. Wallace

1. The Investigation shows that there are six coal beds of major importance in McDowell County from the standpoint of present production - Pocahontas No. 3, Pocahontas No. 4, Pocahontas No. 5, Sewall, Beckley, and Pochontas No. 6 - and five beds of minor importance - Iaeger, Douglas, Welch, Pocahontas, No. 9, and Eagle. The Pocahontas No. 3 bed contains the largest remaining, known reserves. 2. Known measured, and indicated reserves in all beds, based on a minimum thickness of 174 inches and on 1,800 tons per acre-foot of coal in place, are estimated at 2,217 Trillion short tons as of January 1, 1951. Of this total, 1,731 million short tons are in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these area, such reserves should be added to he total estimated reserves.

Jan 1, 1952

By Curtis D. Edgerton

Miami Oölite limestone is the only significant construction mineral in southeastern Florida. Its source area coincides with that of rapid urban expansion. Two-thirds of the existing resource is already unavailable because of development. Land-use conflicts place future availability of limestone in jeopardy. However, a sufficient limestone resource to meet demand for many years is present if its extraction is not restricted. Adverse environmental effects of quarrying Miami Oölite are not severe; land values often increase following quarrying. Future availability depends upon--(l) achieving uniformity of Federal, State, county, and municipality statutory requirements governing quarry operations; (2) setting aside specific land areas for future quarrying; and (3) cooperative planning to provide for land utilization upon completion of quarrying.

Jan 1, 1974

By J. A. Baicker

A prototype borehole probe for ore grade determinations by means of in-situ neutron activation analysis was designed, built, and tested in a two-phase program. Phase I dealt with the design and fabrication of a borehole logging system for operation in 7.6 cm (3 in.) diameter or larger boreholes. It consisted of a 5.06 cm (2 in.) diameter borehole probe containing an intrinsic germanium detector, a canister-type solid cryogen cooling system, cooled FET preamplifier, linear amplifier, high voltage supply, analog-to-digital converter, microprocessor-based multichannel analyzer, buffer memory, bi-directional cable link, power supplies, and a Californium-252 neutron source. A surface support vehicle was designed and outfitted. A minicomputer system was constructed and software developed and tested. In Phase II the system was field tested at several mine sites. The system was calibrated, tested, improved, and demonstrated in a variety of applications. Tests were performed at sites pertinent to uranium, iron, coal, copper, silver and gold. Technical feasibility was demonstrated for all these applications except gold; the gold results were inconclusive. In-situ neutron activation analysis using high resolution gamma ray spectrometry was found to be a potentially viable logging method for are grade analysis under certain conditions.

Jan 1, 1984

By C. W. Owings

"Ventilation is one of the most important features of coal mining, and if a mine is exceptionally gassy it is often difficult to ventilate it in such a way as to make it safe. The general system of splitting the main air current so that two, three, or more sets of room entries are ventilated by the same current of air does not provide a safe method if non-permissible electrical equipment, such as cable-reel, crab-reel, or trolley locomotives are used on gathering haulage, or if open-type hoist or pump motors are used. The problem has been greatly simplified at the Crucible mine of the Crucible Fuel Co. at Crucible, Pennsylvania.The system is not only applicable to the room-and-pillar method of mining, but it may be adopted for any panel system of mining. There also appears to be a definite application in mechanized mining, where the rapid extraction often results in inadequate attention to ventilation and where the gassiness of the section generally increases because, as compared to hand loading, the methane has less time to drain off. The system to be described should commend itself to coal-mining men.ACKNOWLEDGMENTSThis investigation was made possible through the courtesy of H. J. Nelms, general superintendent. E. M. Marshall, safety inspector, E. G. Sauers, assistant superintendent, and Thomas Mark, mine foreman, assisted in the collection of information."

Sep 1, 1931

By A. J. Kauffman Jr.

The Petrographic Section of the Bureau of Mines, Northwest Electrodevelopment Laboratory, Albany, Oreg., annually examines thousands of minerals and rocks. Samples are received from mining, engineers, prospectors, and government agencies, both State and Federal. During the past 2 years certain uncommon minerals have been identified in the samples submitted. Eleven occurrences have been selected for reporting in detail. These selections were made because in most cases a new locality is involved. The data reported are the result of application of the latest techniques, and widely disseminated references concerning each mineral have been added for completeness. Several occurrences have been described by other investigators; in those cases new data have been supplied to supplement the already published information on these occurrences. No uranium-bearing minerals have been included; they will be treated in another paper. The Bureau of Mines does not make chemical analyses or assays for individuals or firms In direct competition with private laboratories. Mineral¬ogical examinations, however, are made for prospectors and the general public. Such examinations a call surface to determine whether the sample in question has possible commercial value. If it has apparent value, the sender is so informed, and suggestions as to its .Arc, development and marketing are offered. The latest scientific apparatus is available to aid in identification. The apparatus includes microscopes, both wide-field and polarizing, a Bunsen-type spectroscope for visual observation of the Zinc and band spectra of many elements, differential thermal apparatus for the examination of hydrous material, apparatus for cutting and mounting either thin sections for study in transmitted or polished surfaces for reflected-light studies, and a high-intensity magnetic separator for concentrating minerals according to their magnetic susceptibility. Also, available, but not an integral part of the Section, are several laboratory-type Geiger counters, a grating spectrograph, and X-ray diffraction apparatus. If need be, all of these tools may be employed to identify a mineral or rock.

Jan 1, 1950

By L. A. Eros

The U.S. Bureau of Mines and Western Fuels Utah, Inc. entered into an agreement to plan, install, and evaluate a micro-computer based monitoring and control system at Deserado Mine, an underground coal mine. The U.S. Bureau of Hines contracted the Colorado School of Mines (CSN) to independently evaluate the project. CSM evaluated and documented costs, benefits, problems, and management and labor perceptions in this report. Recommendations are provided for mine operators and monitoring system vendors considering future installations.

Jan 1, 1986

By W. W. Adams

Increased employment and a lower accident-frequency rate were the outstanding features of the metal- and nonmetal-mining4 industries of the United States in 1939 compared with 1933, according to reports furnished by individual mining companies to the Bureau of Vines, United States Department of the Interior. Except for 1937, the reports for 1939 showed gains both in number of employees and number of mar -hours worked over all years since 1929. The accident-frequency rate per million man-hours of exposure to mining hazards was lower than in any year since 1925. Reports for 1939 revealed a total of 111,909 men employed in and about mines, an increase of inure than 8 percent over 1931 The total volume of labor performed at all mires was slightly more than 299 million plan-hours, an increase of mare than 10 percent over 1938. As these gains suggest, the average employee had a longer period of work in 1939, the increase amounting to r workdays per employee.

Jan 1, 1941

This manual is for use by mine operating personnel and vehicle manufacturers in the selection and proper use of automatic fire protection systems for underground metal and non-metal mining vehicles. Most of the currently available systems are manually operated, dry chemical fire suppression systems. When properly designed, installed, and maintained these systems have proven to be effective both in fire suppression and in withstanding the rugged mine environment. Portable fire extinguishers and manually actuated systems have provided adequate protection for most of the reported fire incidents. However, there have also been incidents where injuries and property losses would not have occurred if the vehicle had been protected with an automatic fire protection system. The need for reliable automatic systems exists when the operator is not present, especially when the vehicle engine is running without the operator in the cab; and also in cases where the operator leaves the vehicle to fight a small fire with a portable and is then forced to abandon the vehicle because the small fire becomes uncontrollable. In the later cases manual systems on the vehicle are never actuated. Although these incidents have been relatively few in number in the past, the increasing use of mobile diesel powered equipment and the related importance of personnel safety, high costs of the mining vehicles, and high cost of down time warrant consideration of automatic fire protection systems. The fire history data and the design concept discussed in this manual were developed under the Bureau of Mines Contract H0252038 which is part of the government's mining research safety program. The purpose of the contract was to develop a low cost, reliable, prototype automatic fire control system for underground vehicles. The industry needs were determined through an extensive mine visitation program, and the prototype system was demonstrated on a vehicle in an underground mine fire test. The system developed under this contract was specifically designed for a load-haul-dump. However, the design concept is applicable to the full general class of mobile underground mining equipment.

Jan 1, 2011

By Gary A. Kingston

This examination of Pacific Northwest (Idaho, Montana, Ore on, and Washington) ferrous scrap-industry opera ions, principally those in Oregon and Washington, points out factors influencing the supply and consumption of scrap materials, such as the complete dependence of steel ingot producers in these States on scrap as a metal raw material and the sizable quantity of scrap exported from Seattle and Portland to Japan. The pattern of the industry is presented as a movement of materials from their diverse sources to the consuming market. The geographic locations of the consuming industries in relation to the area generating scrap materials and the movement pattern of the supply from source to destination strongly influences the cost of the commodity. The best measure of the scrap supply available in an area is experience in terms of how much scrap was withdrawn at a given price. Scrap availability is not finite, because the return of materials as scrap is secular and influenced by constantly varying market conditions. Steel ingot producers use 75 percent of the approximate 500,000 tons of scrap consumed in Oregon and Washington; steel foundries take 15 percent of the total; and iron foundries, ferroalloy plants, and other miscellaneous consumers utilize the remainder. Also, from 1955 to 1960 an average of about 200,000 tons has been exported annually from Oregon and Washington. The foreign exports are supplemented by lesser .shipments to other steel producing States, principally in the western United States. From 1955 to 1960 the preferred and higher value heavy melting scrap grades accounted for about 60 percent of total withdrawals which varied between 600,000 and 950,000 tons annually. Total scrap withdrawals from Oregon and Washington are projected to 1.8 million tons by 1985, 60 percent (1.1 million tons) of which will be heavy melting grades. No. 1 heavy melting scrap is most attractive to scrap consumers at $35 per ton or less. Price-supply relationships compared with projected scrap requirements indicate future prices possibly over $35 per ton. High prices over a long period could motivate the Pacific Northwest scrap consumers to produce steel from iron ore. However, technologic changes taking place at integrated steel plants could reduce scrap withdrawals from the Pacific Northwest, which might keep the scrap price sufficiently attractive to obviate production of competitive iron products by the Pacific Northwest scrap consumers.

Jan 1, 1964

By David A. Summers

Coal is increasingly viewed as one of the major fuel resources of this country for the remainder of this century. The need to extract a greater percentage of the coal in a given seam, together with advantages of improved safety, indicates that longwall mining will become more widely used within this time frame. A novel method of mining coal on a longwall face, utilizing high pressure water jets, is herein described. The mining machine proposed will exploit the stress conditions which exist on a longwall panel in order to achieve the required productivity while at the same time reducing respirable dust and methane ignition hazards. The water jets will excavate only the boundary of the extracted seam section, and thus the energy requirement of the machine will be minimized. The action of the machine is similar to that of an existing coal plow, except in that the wedge teeth of the plow are replaced by oscillating high pressure water jets. The machine can, therefore, cut to the depth and at the speed of existing shearer units at equivalent power levels. The removal of impact stresses from the machine will reduce downtime required for maintenance and replacement of picks and lower the load on the haulage motor of the system. The ability of the machine to increase the depth of cut without an increase in horsepower will further improve productivity when transportation systems to remove the greater production are in operation.

Jan 1, 1974

By Carlton E. Brown

Broom and Yant6/ recently described a. microprojection method for determining the particle-size distribution and number concentration of samples of dust collected from the air by such samplers as the Owens jet dust counter) and the thermal precipitator8/ . This method was developed to obviate or reduce the eyestrain consequent to the regular filar-micrometer method9/ and to save time and work. The article stated that work was in progress on a micrcprojection method for counting impinger dust samples; this article describes the method developed. ACKNOWLEDGMENTS The assistance of the personnel of the ventilation Department of the Anaconda Copper Miring Co., Butte, Mont., in developing this method and particularly in suggesting a suitable material to use for the microprojector screen is sincerely appreciated. Much of the work was done in the laboratory of the Anaconda Copper Mining Co. on samples collected in Butte mines during a cooperative study with this Bureau.

Jan 1, 1938

By G. W. Jones

In cooperation with the Edison Electric Illuminating Co. of Boston, Mass., and the Boston Consolidated Gas Co., a survey has been conducted continuously since 1929 by the Bureau of Mines to determine the general hazards of combustible gases and vapors in manholes of the Edison Electric Illuminating Co. The New England Telephone & Telegraph Co. also has cooperated in the investigation, and tests have been made in its manholes since May 1, 1933. Yearly reports6/ on the results obtained since the beginning of the survey have been published. The method and procedure of conducting the survey in 1936 were the same as heretofore.

Jan 1, 1938

By G. W. Jones

In cooperation with the Edison Electric Illuminating Co. of Boston, Mass., and the Boston Consolidated Gas Co., a survey has been conducted continuously since 1929 by the Bureau of Mines to determine the general hazards of combustible gases and vapors in manholes of the Edison Electric Illuminating Co. The New England Telephone & Telegraph Co. also has cooperated in the investigation, and tests have been made in its manholes since May 1, 1933. Yearly reports6/ on the results obtained since the beginning of the survey have been published. The method and procedure of conducting the survey in 1936 were the same as heretofore.

Jan 1, 1938

By R. S. Fowkes

The degree and manner of packing of bulk materials influences all phases of their loading, such as by a front end loader or a dragline, and their mechanics of flow, such as through a binhopper or an ore pass. The most important quantity in analyzing the handling of a bulk material is its shear strength which depends primarily on the same parameters as those that determine the packing state. Some of these are size, size distribution, moisture content, particle shape, particle orientation, and cohesion. The variables that affect the packing state arc vibration, pressure, intensity of deposition, velocity of deposition, and, when the material is confined, container used. The analysis of packing by a number of investigators has been done almost entirely with spherical particles. Most of these studies have dealt with monosized spheres. There is scant information on particles with angular shapes. Since most of the investigations by far have been concerned with ceramics and powder metallurgy, the particle sizes and ranges of size distribution have been small compared to those generally found in mining after fragmentation.

Jan 1, 1974

By A. Wahab Khair

"This paper presents an analysis of fracture mechanisms in coal subjected to bi-axial state of stresses, indentation of laterally confined coal specimen. Coal specimens were loaded to failure by the straight wedge indenters at various lateral confinement pressures. Strain distribution and acoustic emission characteristics of coal specimens under stress were recorded. The influence lines of vertical forces acting on the horizontal straight boundary of the coal specimen for each type of wedge indenter have been established using holographic interferometry technique. The effects of wedge indenter angle, confinement pressure, and coal anisotropy on fracture types, failure modes, and post-failure conditions were studied. The results indicated that combined application of holographic interferometry and acoustic emission monitoring techniques is not only suitable ·for studying deformability of heterogeneous and microscopically discontinuous material under stress but it also enhances the mode of fracture during the post failure stage. INTRODUCTIONOne of the relevant processes in the coal cutting technology is the application of indentation theories. Since most cutting tools in the coal industry are wedge shaped most of the indentation research is found for a wedge shaped tool.A wide range of behavior is found in different rocks subjected to the wedge penetration. A rock which is elastic brittle at standard pressure might become elastic plastic at high confining pressure (Gnirk and Cheatham, 1963). It was also observed that some rocks will merely be crushed and indented by a wedge whereas others will crack and form chips, furthermore the existence or non-existence of chips depends mostly on the geometry of the indenter, type of rock and the depth of penetration (Evans and Murrel, 1958). However, coal cutting technology is mostly explained by models which use rigid wedge to penetrate into a brittle material in which both crushing and chipping will occur (Evans and Murrel, 1958, 1962)."

Jan 1, 1988

By S. A. Allen

The Eufaula bauxite district of Barbour and Henry Counties in southeast Alabama covers an area approximately 14 miles long, 6 miles wide at the eastern extremity near the Chattahoochee River, and 10 miles wide at the western end near the east fork of the Choctawhatchee River (see figs. 1 and 2). The long axis of this polygon bears a little south of east.

Jan 1, 1949

By G. S. Rice, J. W. Paul, M. W. VONBERNEWITZ

This bulletin abstracts and reviews essential details of reports on 59 fires in different coal mines in the United States, describes the circumstances of origin and the methods of controlling or extinguishing the fires, and points out the lessons taught. all, the fires caused great damage to property and killed nearly 400 men. The data have been compiled from the records of the Bureau of Mines, which cover most of the major mine accidents in the United States since 1.908. The names of the mines concerned and of the persons connected with the management of those mines have been omitted in accordance with the usual policy of the bureau. The bureau hopes that this bulletin will be of service to all persons interested in lessening the fire hazard at coal mines and to all who may be called on to fight a mine fire.

Jan 1, 1927

By C. H. Bloomster

This study estimated (1) radon and radon daughter emissions from underground uranium mines; (2) the reduction in radon that would be released to the surface by using control techniques such as bulkheads, sealants, backfilling, and positive pressure ventilation; (3) the cost for radon and radon daughter removal from total exhaust air; and (4) total radon and radon daughter discharge for lower occupational exposure limits. For 13 large underground uranium mines, estimated yearly radon emissions from each mine ranged from 900 to 3,400 Ci. The estimated age of air emitted from the mines ranged from 11 to 37 min. Potential radon removal methods for the total mine exhaust were evaluated. The cost of these methods was prohibitive. Diurnal and seasonal changes may affect radon emission over short periods of time, but do not affect the total emissions over the long run. Radon and radon daughter emissions would be little changed by increased ventilation requirements needed to achieve lower occupational exposure limits. The concentrations in the exhaust would be lower, but the total release would be the same

Jan 1, 1984