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By Oliver Bowles

[Simple systematic accounting that adequately records all transactions has long been regarded as essential to the welfare of any business enterprise. Some of the defects that detract from the prosperity of the slate industry are attributable to a lack of effectiveness in cost keeping. This condition has promoted the United States Bureau of Mines to make a detailed study of accounting methods for the slate industry, and to present for consideration a system of accounts, which it is believe would enable the industry to attain more economical management and operation if accepted by a fair proportion of its important units. The method of accounting presented herein has been worked out with the assistance of leading slate producers and the recommendations are tentative and are submitted in this form as a means of developing constructive criticism. Believing that cooperative effort in this, as in many ether problems will bring the most enduring benefits to the industry as a whole, the writer urges that the cost earnest consideration be given to this vital problem now facing the slate industry.]

Jan 1, 1929

By Charles Vaught

The purpose of this study was to determine mine workers' state of fie-fighting preparedness and the technology being used to detect and respond to underground coal mine fires. To investigate this problem, 214 underground coal miners were interviewed by U.S. Bureau of Mines researchers. Frequency distributions of workers' responses are presented in this report, along with segments of narrative accounts, to profile miners' fire-fighting capabilities. The data indicated that much variability exists from mine to mine and that there are several important changes operators may undertake in order to make miners better prepared to deal with fire underground: select appropriate sensors, establish and test a warning and communication protocol, construct a system capable of delivering hundreds of gallons of water per minute for sustained periods, institute formal fire preparedness audits, develop case studies of events that occur at an operation to use as teaching and assessment tools, and provide structured practice that can be incorporated into fire drills.

Jan 1, 2010

By Deno M. Pappas

The purpose of this Bureau of Mines study of U.S. roof and rib (roof- rib) accident statistics and related accident costs is to define current accident trends (1980-84) associated with fatal and nonfatal roof-rib fall accidents. Data were retrieved from a data base containing all recorded U.S. mining accidents, then sorted and normalized utilizing a computer software program. The statistics indicate that roof-rib accidents have significantly declined in the 5-yr study period. Moreover, they indicate that there have been increases and/or patterns of roof-rib accidents associated with specific mine characteristics, such as seam height, mine size, geographic location, and seasonal variations. Also, roof-rib injury characteristics produced pattern changes involving worker activity, lost workdays, types of injury, and severity of injury. A conservative estimate indicates that there has been a 30% adjusted increase in the cost of a roof-rib accident over the 5-yr study period.

Jan 1, 1987

By L. Keith Hudson

The purpose of this study is to provide data that demonstrates that the Alcoa flash calciner design can be used for the decomposition of AlCl3?6H2O to A1203. Heat and material valance data for calcination provides data on the partial pressure of HCl in the off-gases. Experimentally determined data for the HCl partial pressure, over solutions expected in producing alumina from clay by the hydrochloric acid process, show that HCl can be absorbed from the off-gases into process solutions to effect crystallization of AlCl3?6H2O.

Jan 1, 1979

By McHenry Mosier

This paper describes the practice in diamond drilling blast holes and discusses the relative merits of this method as compared with drilling by percussion rock-drills at eastern magnetite mine A. The rooke that were drilled included: (1) Gneiss; (2) sohist; (3) crystalline limestone; and (4) granular masses of magnetite. The principal stoping methods were: (1) Sublevel open stoping and (2) inclined room-and-pillar. Diamond drilling was used in the sublevel stopes and in some of the large pillars in an old section of the mine. Experimental work on diamond drilling blast holes began in 1943. Drill- ing proved difficult owing to the occurrence of fingers of extremely hard barren rock in the magnetite ore. All diamond drilling was contracted to a firm that furnished everything necessary for drilling except compressed air and water. In most instances the diamond-drill machine is clamped directly to a 3.5-inch column to reduce vibration. For drilling in floor pillars in open stopes, the drill was set on a demountable, sectionalized steel, frame with four legs carrying a 20-foot, 3.5-inch, extra-heavy pipe. "Both coring and noncoring bits were tried. In holes drilled with a cor- ing bit, the core was ground into sludge as the bit advanced so that it was unnecessary to delay drilling for pulling core. Data on tests with several types of bits are given as well as some oper- ating results. A direct comparison of costs between diamond drilling and percussion drilling was not available. The advantages of diamond drilling blast holes at mine A included: (1) Safer working conditions in open stopes. (2) The recovery of additional ore. (3) A reduction in the amount of stops development.

Dec 1, 1946

By C. A. Herbert

This paper sets forth the hazards of accumulations of explosive mixtures of methane and air due to inadequate ventilation, the causes of which are discussed as follows: 1. Lack of well-maintained air courses. 2. Air losses due to leaky stoppings, trap doors, and overcasts. 3. Faulty mining methods. 4. Poor supervision. A modified plan of room-and-pillar panel mine development is suggested, which, it is believed, will eliminate many off the hazards of gas accumulations inherent in the present method of mine development. It is also suggested that some water-proofing agent be used on the roof of permanent air-course entries in conjunction with roof bolting to eliminate the detrimental effect of the moisture-laden atmosphere during summer and thus prevent serious roof falls.

Jan 1, 1953

By R. L. Crosby, L. W. Higley

Magnesium- rich magnesium- aluminum- zirconium alloys in the cast and in the extruded and heat- treated condition were studied to identify the phases present and to determine phase distribution . In cast alloys , two intermetallic compounds were identified : ZrAla by X- ray diffraction ; and Mg₁ Al₁₂ by microscopical observation . Based on microscopical comparisons between the known phases in the cast structures and the phases in the structures of extruded and heat - treated rods , ZrAl₂ and Mg1 , Al12 were identified in the structure of the latter . The presence of these intermetallic compounds in rod specimens could not be confirmed by X- ray diffraction . ZrAl₂ was observed in the structure of extruded and heat - treated rod specimens containing as little as 0.01 weight - percent zirconium . The presence of aluminum restricts the solubility of zirconium in magnesium because of the strong tendency to form ZrAla . This intermetallic compound segregated in clusters of small particles in the matrix of cast alloys , and only slight improvement in distribution was noted when the alloying techniques were varied .

Jan 1, 1964

By David C. Oyler

Three long horizontal holes were drilled from a directionally drilled surface hole at the Emerald Mine near Waynesburg, Pa. The purpose was to adapt the technique of directional drilling for use in draining methane from coalbeds. A 504-m (1,652-ft) long, 76-mm (3-in) diameter, circular arc pilot hole was drilled, using a downhole mud motor, to enter the Pittsburgh coalbed at a vertical depth of 305 m (1,000 ft). The hole was reamed to 222 mm (8-3/4 in) and was cased to a measured depth of 486 m (1,595 ft). Three 76-mm (3-in) diameter horizontal drainage holes were then drilled, totaling 2,909 m (9,544 ft) of horizontal hole. Improvements in drilling methods increased the average drilling rate from 20.4 ill (67 ft) to 64.9 m (213 ft) per day. The cost of drilling the directional and horizontal holes (using a Government-owned drill rig) was $1,169,530, a figure inflated by inexperience and by delays caused by lost-circulation problems and fishing operations. An estimated total drilling cost of $960,000 (including rental of a drill rig) for an improved system, was determined by a detailed cost analysis. Initial gas and water production from November 1979 through May 1980 was low because of caving of the horizontal holes drilled in shale near the bottom of the casing.

Jan 1, 1982

By K. P. Wang

SIGNIFICANT general developments took place in the Far East during 1964, with far-reaching repercussions on the mineral and industrial economies of individual countries and the region as a whole. Japan, during this, "the Year of the Open Door," ushered in the era of industrial maturity, greater independence in economic policy, and expanded technical assistance to less developed countries. Symbolic of its dynamic economic growth is the fact that Japan out-produced the Federal Republic of Germany in steel during 1964 to take over a third-ranking world position. Mainland China, recovering from the "Leap Forward" debacle, made significant gains in industrial output. Mainland Chinese trade with Japan was on the upswing, and discussions were held between the Chinese and the Soviets for possibly resuming Soviet aid in industrial and mineral development. Meanwhile, United States aid to Taiwan was being phased out because of progress achieved. Rapprochement between South Korea and Japan was imminent late in 1964, a factor which may well affect South Korean mineral development. The Indonesian-Malaysian confrontation created economic difficulties in both countries. The war in Viet-Nam seriously disrupted industrial activities, particularly in the south.

Jan 1, 1966

By Charles Vaught, Richard S. Fowkes, Ronald S. Conti, Barbara Fotta, William J. Wiehagen

The purpose of this study was to determine mine workers' state of fire-fighting preparedness and the technology being used to detect and respond to underground coal mine fires. To investigate this problem, 214 underground coal miners were interviewed by U.S. Bureau of Mines researchers. Frequency distributions of workers ' responses are presented in this report, along with segments of narrative accounts, to profile miners' fire-fighting capabilities. The data indicated that much variability exists from mine to mine and that there are several important changes operators may undertake in order to make miners better prepared to deal with fire underground: select appropriate sensors, establish and test a warning and communication protocol, construct a system capable of delivering hundreds of gallons of water per minute for sustained periods, institute formal fire preparedness audits, develop case studies of events that occur at an operation to use as teaching and assessment tools, and provide structured practice that can be incorporated into fire drills.

Jan 1, 1995

By L. A. VANFLEET, Allen D. Look

The ever -present danger of mine fires and the possibility of hazardous atmospheric conditions in underground mines make a well-equipped mine rescue station a valuable asset to any mining district . Rescue equipment without proper maintenance provides only false security , because neglect may make the apparatus unfit for use in an emergency . Promptness in fighting mine fires is important ; frequently the first 30 minutes of action are worth many hours later . Likewise , the equipment will be of little value if enough men trained in its use are not readily available . This circular points out how such protection has been provided in an Arizona mining district by establishing a well- organized , adequately equipped , central mine rescue station. ·

Aug 1, 1950

By Frank E. Cash

The compensation-insurance rates for quarrying in North Carolina are 11 times higher than for the State?s major industry, textiles. Some operators are willing to accept this as representing the ratio of existing hazards. This was not true of the management of the Southern Aggregates Corporation, and in 1935 it tools definite steps to correct the idea of its local officials and employees that loss of life and limb in quarries is inevitable. ACKNOWLEDGMENTS The authors acknowledge gratefully the assistance and information concerning these operations furnished by H. M. Shaw, safety director (also secretary and treasurer), Southern Aggregates Corporation, Raleigh, N. C.; by the following superintendents: J. H. Rodgers, Blair Quarry, Blair, S. C.; J. D. Lane, Greystone and Rolesville Quarries, Henderson, N. C. ; J. H. Arthur, Guilquarry, Stokesdale, N. C.; J. H. Watkins, Rockton Quarry, Wendell, N. C.; P. A. Wellenborne, Reidsville Quarry, Reidsville, N. C.; and J. L. Kirchin, Woodleaf Quarry, Woodleaf, N. C.; by the various foremen at the plants, and by Murry Id. Grier, safety engineer, North Carolina Department of Labor, Asheville, N. C.

Jan 1, 1940

By Eugene Frey

"INTRODUCTION The Good Fortune mine was sampled by an engineer of the Bureau of Mines in June 1944. Project 984 was set up under the strategic minerals program to make old workings accessible for this sampling program. Actual operations commenced June 1, 1944, and were completed June 30, 1944.The deposit was visited and discussed briefly by Sidney H. Ball 3/ of the Federal Geological Survey in the summer of 1906 and by H. M. Chance 4/ several times from 1887 to 1900.LOCATION AND ACCESSIBILITYThe Good Fortune mine is situated in the Hartville mining district in Platte County, Wyo., approximately 9 miles northwest of the town of Guernsey. The property is about 100 miles north of Cheyenne, Wyo. (fig. 1).ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective 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 exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metal¬lurgical Branch, O. C. Ralston, chief, analyzes samples and performs beneficiation tests."

Aug 1, 1947

By Robert C. Dyni

The use of techniques and equipment designed to pneumatically place backfill into an underground mine opening through boreholes for subsidence abatement has historically met with limited success, largely due to the inability to directly monitor the placement of the backfill in the opening. The success of a backfilling project cannot be guaranteed if it is not known whether the underground opening has been completely filled with backfill material. To overcome the inability to directly monitor backfill placement, the U.S. Bureau of Mines developed a pneumatic backfilling system that allows for direct viewing of the backfill as it is placed in an underground mine opening. This system utilizes a recently developed pneumatic nozzle coupled with an instrumentation package that allows for real-time observations and measurements of backfill placed in an underground opening through a borehole. The nozzle utilizes a high-velocity airstream to redirect backfill falling through a pipe in the borehole and directly in front of the nozzle; the airstream redirects and propels the backfill horizontally into the .mine opening at over 100 ft/s. The instrumentation package, mounted directly to the nozzle, contains a video camera, high-intensity lamps, laser-rangefinder, electronic compass, and water sensor.

Jan 1, 2010

By Ernest E. Berger

"INTRODUCTIONOne of the outstanding problems in the normetallic industries, and one which involves two of the greatest of these industries, cement and gypsum, is the reaction of Portland cement with calcium sulphate. To all Portland cement clinker there is added in the manufacturing process, a small amount of retarder, as a necessary ingredient of the finished product. This retards the initial set, increases the strength, and adds to the plasticity of the cement so it will have the desired working and setting qualities. The retarder commonly used is gypsum, (CaSOA.2HO), which is the hydrous form calcium sulphate. Calcium sulphate is also available as plaster of Paris (CaSO4 1/2 HC) and anhydrite (CaSO4). The purpose of this inquiry was to determine the form or mixture of forms best adapted for retarder. The problem is complicated by the fact that cement clinker is a complex mixture of calcium silicates and aluminates, and that clinker from different mills, making cement of approximately equal quality, differs considerably in chemical constitution. Thus the same retarder may give very different results with different types of clinker, especially in the percentage of retarder required for the same degree of retardation.It has been known for some time that a small percentage of plaster of Paris will greatly retard the time of set of Portland cement as well as increase its strength and plasticity, but whether gypsum and anhydrite will have a similar effect is as such disputed question. The offects of gypsum have received little consideration in laboratory research because, even though it will not retard a clinker when the two are mixed in the laboratory, as has been noted in some instances, the cement will have a normal set when the two arc mixed in the large tube mill at the plant, so that practically, gypsum seems to be equally as goou as plaster of Paris, and because of the great saving in cost it has been used almost exclusively."

Sep 1, 1925

By M. K. Quinn, N. P. Reddy, A. W. Khair

"An analysis of coal fragmentation due to the action of a continuous miner is presented. Underground coal cutting by a drum-type continuous miner was simulated in the laboratory using a specially designed unique automated rotary coal cutting simulator (ARCCS). The rotary coal cutter provided the versatility of varying the operating and in-situ parameters to provide information on the effects of generating 37 pm (0.0015 in) particles. In these tests, coal blocks with an approximate dimension of 50.8 x 35.6x 20.32 cm (20x 15x 8 in) were first subjected to confining pressures equivalent to in-situ conditions. The blocks were then cut by the rotary cutting head of the ARCCS, thus simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-situ and operating parameters a number of other parameters such as (1) penetration of bit into coal, (2) penetration resistance (thrust and cutting pressures), (3) rotating velocity of' cutting head, and (4) acoustic emission activity in the coal block were monitored. During the test, all the cut products were collected for size distribution analysis. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted using a sonic technique. At the end of each experiment the cutting paths of the bits in coal were photographed using a camera attached to an optical microscope.The results led to a better understanding of the mechanisms of the fragmentation process during coal cutting and the effect of operating parameters, in-situ conditions and coal type on the size distribution of the cut product:"

Jan 1, 1989

By A. D. Garman

This paper presents one of a series of digests of foreign mining legisla- tion and court, decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Latin America has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it is being referred through the courtesy of the Department of State. Individual abstracts of the laws of each of the countries herein discussed have been prepared and published separately. This general summary is presented for the use of mining engineers and investors whose interests extend over the borders of a single country. It is also designed to bring out certain general principles of mining law and, so far as feasible, to indicate the trend of mining legislation in South and Central America. In order to gain perspective, the details of legislation are not com- pletely covered in this paper, but an effort has been made to bring out essential differences as well as points of similarity in the laws of the various countries. The course of legislation is first traced chronologically and the points discussed are then arranged in tables in somerhat greater detail. .Si. With a very few exceptions the existing mining legislation of Spanish America is a development, of the Spanish "Law Decree of Bases" (more briefly referr- ed to as the "Decree-Bases") of 1868. This in turn was influenced, particularly in its classification of minerals, by the French law of April 21, 1810.

Jul 1, 1930

By Raja V. Rarnani, Robert L. Frantz

More than 100 scientists from diverse professional backgrounds have contributed their expertise to the Dust Center as investigators. Approximately 50 researchers served as principal investigators, with responsibility for directing the work on Center projects, from experimental design and implementation in mines and in laboratories to coordination of efforts within the research infrastructure of the Center. The professional biographies which follow demonstrate the breadth and depth of research capabilities brought to the Center by its principal investigators.

Jan 1, 1995

By Oliver Bowles

Limestone, including dolomite, is the most widely used of all rocks - nearly 300 million tons annually in the United States alone. It occurs in some form in every State and is produced in thousands of localities. Because of its attractiveness, substantiality, and durability it is employed extensively as a building stone. In crushed and broken form it is used for concrete aggregate and railroad ballast and in highway construction, metallurgy, agriculture, and a host of chemical and industrial processes. This paper proposes to furnish general information on the origin and occurrence of limestone and dolomite, chief production centers, major uses, and methods of quarrying and preparing stone for market. Footnote references will guide the reader to sources of more complete information.

Jan 1, 1956

By John J. Henn

An evaluation is presented for an ammonium sulfate leaching process designed to extract manganese from Cuyuna, Minn., and Aroostook, Maine, deposits. In this process the manganese and iron in the ore are reduced to MnO and Fe 3 0 4 in a shaft furnace; the reduced ore is then leached with ammonium sulfate solution forming soluble manganous sulfate while leaving most of the iron undissolved. After filtration, the manganese and some impurities are precipitated from solution as carbonates which are then pelletized and calcined to form a product composed mainly of Mn3O4. The plants are designed to produce 100 tons per day of manganese contained in a product that is suitable for the production of ferromanganese. A byproduct credit, together with the extra processing cost, is included for the Cuyuna ore processing plants because Fe2O3 may be recovered for use in blast furnaces. The estimated operating costs per ton of manganese, excluding income taxes and return on investment, are: [ ] The process with or without byproduct recovery, when treating Cuyuna or Aroostook ores, is not economically competitive with ores available at $71.43 per ton of contained manganese.

Jan 1, 1968