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By H. C. Ko

Heats of solution of calcium carbon-ate (calcite) and calcium oxide in hydrochloric acid were determined by solution calorimetry. Combination of these two heats yields a value of 42.643±0.024 kcal/mole for the enthalpy of calcination of calcite at 298.15 K. Literature data on ?H°298.15 of calcination of calcite were reviewed and compared. Thermodynamic properties for the calcination process were calculated from 298.15 to 1,500 K using Gibbs energy functions. This research was undertaken by the Bureau of Mines as an effort to provide thermodynamic data for the advancement of minerals technology, energy conservation, and environmental preservation.

Jan 1, 1982

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

C 2 Complete Hoisting Systems A Above Ground Installations A total of seven companies were identified who supply complete emergency escape hoist units for above ground installations The units have been designed predominately to meet the needs of coal mine operators to satisfy the requirements of the Coal Mine Health and Safety Act of 1969. The seven companies are as follows 1 Dover Conveyor and Equipment Co. 2. Coeur d' Alenes Co. 3. Connellsville Corp. 4. Scott Midland 5. W W Williams Co. 6. Equipment Corporation of America 7. Timberland Ellicott Table VIII contains detailed specifications and price information on each of these units. The units have a number of similarities

Jan 1, 1976

By T. J. Lutz, G. T. Homce

A standard Ford1 4600 agricultural tractor was converted to remote control to perform ASAE/SAE field upset tests (rear rollover and side rollover). This paper discusses the engineering process to develop a remote-controlled tractor in determining the critical parameters of operation, to choosing appropriate actuators, designing the circuitry to control them, installing the actuators on the tractor, testing the system for functionality and then conducting numerous overturn tests. The system uses off-the-shelf components for simplicity, replaceability, and economic concerns. The remote control system has withstood 21 tests to date with no failures and will continue to be used for at least three more years of testing.

1. Mining to prevent and control underground acid formation should begin with education imparted through: (A) Course work at mining schools to teach prospective engineers. (B) Training of engineers presently employed in the mining industry through appropriate mining extension courses. 2. Considerable need exists to devote more attention to: (A) Hydrogeologic studies of mining areas to enhance the planning of new mines and the abatement program of existing mines. (B) Additional research to explore methods of dewatering the strata associated with mining areas. (C) Further effort to develop sealants for preventing contact between water or oxygen and the acid producing material associated with the coal seam.

Jan 1, 1970

By A. J. Farstad, R. G. Olsen

The Coal Mine Health and Safety Act of 1969, passed by Congress in the wake of the disaster at Farmington, West Virginia, led to an extensive study by the National Academy of Engineering of the problems involved in coal mine safety. One of the results of this report and subsequent research conducted by the U. S. Bureau of Mines has been the investigation of electromagnetic techniques for the location of trapped miners after a mine emergency. The Westinghouse Georesearch Laboratory has been involved in both the 2 theoretical and field studies relating to this problem. A compact personal beacon transmitter has been developed which can be attached to and powered by a miner's lamp battery. A compatible lightweight loop antenna package has also been developed which can be easily carried on a miner's belt. This antenna can be quickly deployed on the mine tunnel floor. For the purpose of calculating its electromagnetic fields on the earth's surface, the loop can be considered to be a magnetic dipole buried in the earth. (The earth is assumed to be homogeneous and to have a conductivity of s mhos/m.) The surface of the earth is assumed to be uniformily sloping and the transmitter dipole oriented as in Figure 1. The fields on the earth's surface can be computed by using a superposition of the fields of a 4 vertical magnetic dipole3 and of a horizontal magnetic dipole in proportions which depend on the slope of the terrain. In the case of level terrain a null in the horizontal magnetic 5 field occurs on the surface directly above the dipole. This null is designated as the apparent source location and is the criterion by which the source is located. The criterion was tested at two hardrock mines and two coal mines in the fall of 1972. The apparent source locations were compared to actual locations determined by conventional surveying techniques. It was found that due to nonlevel terrain the apparent and actual source locations differed by up to 13 meters. This discrepancy can be resolved by an examination of the fields of a source beneath uniformly sloping terrain. Figure 2 shows the experimental and theoretical results for a

Jan 1, 1973

By A. C. Johnson

The Ellington manganese deposit in Reynolds County J Mo., had been known for some time; and limited exploration, consisting of test pitting and sinking a shaft 54 feet deep on the property, had been done by private interests. Late in 1941, the Bureau of Mines cleaned, deepened, and sampled many of the existing pits and dug and sampled 27 new ones. The shaft was unwatered and sampled, and several pockets of manganese ore were trenched to determine their extent. Samples were analyzed and beneficiation tests on 1 ton of the ore were made at the Rolla, Mo., station of the Bureau of 'Mines. Results of the investigation indicated that the deposit was small and low in manganese content.

Jan 1, 1948

By Owen W. Terry

During the summer of 1943 the Bureau of Mines conducted an investigation and program of churn drilling on the McIlhon and adjoining Pearson land in the Mineral Point district of Iowa County, Wis. Sixteen holes, aggregating 1,570 feet .of bore, were completed. The work was undertaken as part of a general investigation of the zinc-and lead-producing area of southwestern Wisconsin at a time when great effort was being made to increase the production of Metals important to the war program. The Bureau's drilling program supplemented a previous drilling pro-gram conducted by the Vinegar Hill Zinc Co., and demonstrated the presence of a strongly mineralized zone at relatively shallow depths.

Jan 1, 1948

By H. H. Fields, Stephen Krickovic, M. G. Zabetakis, Albert Sainato

The Bureau of Mines is in the process of degasifying a virgin area in northern West Virginia from the base of an 839-foot -deep vertical borehole. An in situ gas pressure hole 199 feet long, and seven degasification holes ranging in depth from 500 to 850 feet (average 618 feet) were drilled in an 8-foot-thick virgin Pittsburgh coalbed from the enlarged (14-foot-diameter) bottom of this borehole. The in situ pressure at the back end of the hole and the range of gas and water flows from degasification holes as they were completed and closed off were 203 psi, 79,000 to 257,000 cfd (average 160,000 cfd), and 5 to 8 gpm per hole (average 6.8 gpm), respectively. Twenty-four hours after the seven holes were connected through individual water traps to a common collector for natural venting of the gas through pipes to the atmosphere, the total gas and water flows and the in situ pressure dropped, respectively, to 971,000 cfd, 1.3 gpm, and 18 psi. Eighty days later the corresponding values dropped to 529,000 cfd, 0.50 gpm, and 13 psi. After 180 days of degasification, 91 million cubic feet of gas had been removed from the affected virgin area. This represents 60 to 70 percent of the gas calculated to be contained in the area of coal affected by the holes.

Jan 1, 1973

By E. R. Cole

Bench-scale research at the Bureau of Mines has resulted in the successful development of a combination electrorefining-electrowinning method for recycling all the lead in scrap batteries. The method reduces energy consumption and eliminates toxic emissions, in contrast to present pyrometallurgical smelting, and the lead produced is pure enough for use in maintenance-free batteries. Anodes cast from molten lead scrap were electrorefined in 1-and 2-liter plastic cells using an electrolyte composition of 70 g/l Pb and 90 g/l free H2SiF6 (fluosilicic acid). Both reagent-grade and waste H2SiF6 were used. Cathode starting sheets were made from refined lead. Aloes, and later bone gelatin, and calcium lignin sulfonate addition agents were employed. The sludge remaining after separation of the lead metal was treated in a two-step leaching operation to solubilize the lead for recovery by electrowinning. Conditions for electrowinning were essentially the same as for electro-refining, except that insoluble Pb02-Ti (lead dioxide-coated titanium) anodes were used. The best results for both electrorefining and electrowinning were obtained with a current density of 170 amp/m2 and a cell temperature of 25° to 35° C. Cathode purity ranged from about 99.9 to 99.99+ pct Pb. Maximum energy consumption after 3 days, for electrorefining and electrowinning, was 90 and 700 kwhr per metric ton of refined lead, respectively.

Jan 1, 1981

By M. R. Geer

The washability examination of a coal establishes the quality of the product that could be prepared by mechanical cleaning, shows how much impurity would have to be eliminated to attain a particular quality of product, indicates what type of cleaning process would be suitable, and tells whether the coal could be cleaned efficiently, The coal-preparation laboratories of the Bureau of Mines make washability examinations of coal for a variety of purposes. Sometimes these examinations are made as an integral part of research conducted on coal-washing problems. Occasionally they are made on coals mined on Government-owned land or on coals destined for use in Government installations. Often they are made on coals from new fields or new beds in existing fields to help establish the characteristics of the Nation's coal reserves. Whatever the original reason for doing the work, the results often are useful later in evaluating deposits or in the design of cleaning plants. Publication of the results of such studies provides for the widest possible usefulness. This report brings together the results of washability examinations made on 1 coal each from Oregon and Idaho, 2 from Wyoming, 5 from Utah, and 11 from Washington. Material of this nature is inherently difficult to summarize. Some of the coals are so clean} despite full-scam mechanical mining, that they could not be improved materially by washing; others present some of the most difficult preparation problems found in the country.

Jan 1, 1961

By M. E. Tyrrell

The purpose of the work leading to this report was two-fold: (1) To determine the properties of cemented tungsten carbide modified by the addition of one, two, and five percent of titanium diboride, and (2) to compare the properties of these mixtures when sintered, hot-pressed, and flash-welded (resistance-sintered). Minor additions of titanium diboride to mixtures of 94 percent WC and 6 percent Co decrease mechanical strength but increase oxidation resistance in proportion to the amount of the addition. One percent of titanium diboride increased the hardness by 2 Rockwell A units. Hot-pressing produced compacts with the highest density and the best mechanical strength, but losses of cobalt were high and grain growth was pronounced.

Jan 1, 1962

Provide guidance on the selection of millisecond initiator delays between blastholes in surface mine blasting to provide a desired degree of rock fragmentation consistent with safety and vibration considerations. The Problem Blasting remains the primary means of fragmenting, rock for all kinds of mining, quarrying, construction, and excavation activities, and it is the only practical and economic method of breaking up and moving large amounts of material such as coal overburden and stone aggregate. Because of the large amount of blasting done, typically using 4 billion pounds of explosive to break about 8 billion tons of rock annually in the United States, a small improvement in blasting performance will have a significant productivity impact. Standard blasting practices involve the selection of time delays in a blast for at [cast three purposes: (1) to control energy flow to minimize adverse vibrations, (2) to provide sufficient time relief for good rock displacement, appropriate muck pile shape for digging, and the prevention of collar violence, misfires, and flyrock, and (3) to provide an appropriate amount of interhole stress wave and gas pressure action for a desired fragmentation size distribution. Timing guidelines that exist are based on subjective observations rather than measurements, even for the relatively new casting methods. Until this Bureau study, no definitive analysis had been done to quantify the fragmentation and productivity of full-scale blast rounds as functions of precision delay timing.

Jan 1, 1989

By Wilbur I. Duvall

In a previous report, entitled A Gage and Recording Equipment for Measuring Dynamic Strain in Rock, a control circuit for a drum camera was described. The purpose of this control circuit was to provide a means for firing seismic caps, synchronizing the firing of the cap with the opening of the camera shutters and generating an electrical impulse at the instant of detonation. The operation of this circuit depended on the following two characteristics of seismic caps: (1) these caps contain a bridge, which breaks at the instant of detonation, and, the firing delay time of the cap is a function of the firing current. During the course of the Bureau's studies, considerable difficulty was experienced from "firing hash", i.e., spurious vibrations that appeared on the records at the time of detonation. The cause of most of this "firing hash" was traced to the intermittent grounding of the cap leads at the time of detonation. As the cap leads were still connected to the firing battery, the grounding of the leads permitted current to flow through the rock to the gage and to return to the firing battery through the shield on the gage cables. The intermittent flow of current along the cable shield produced potentials on the gage leads that were recorded as the "firing hash." To eliminate this difficulty, it is necessary to remove the firing voltage from the cap leads the instant the cap detonates. This report supplements the previous report and describes an improved circuit that can be used to fire seismic caps, remove the firing voltage from the cap leads the instant the cap fires, control the firing delay time in the cap, and generate reference signals at the time current starts flowing in the cap circuit and at the time the cap detonates. These reference signals can be used to determine the firing delay time of seismic caps and the time at which the seismic wave is generated by the explosion.

Jan 1, 1950

By D. Harrington

"A tabulation is printed below showing the accident record of the thirty-two mines of the Anaconda Copper Mining Co., in Montana, for the years 1915, 1916, 1917, 1918, 1919 and 1920, with summation for the six years. The table gives the number of shifts worked by each mine with the serious plus fatal accident rate for each 10,000 shifts worked.It is seen that in a total of 16,460,767.5 shifts worked by employees of the company's mines during this six-year period, there were only 2,005 serious and fatal accidents and of these, 200 were fatalities, leaving 1,805 serious accidents (a serious accident being one in which 14 or more days' time are lost). This is at a rate of 9,120 shifts per serious accident and at a rate of 82,304 shifts per fatality. Hence, if 300 days be adopted as a year's work, there would be one fatality per 274.3 years of work in these mines and one serious accident for every 30.4 years work.According to Bureau of Mines Technical Paper 286, (Metal-mine accidents in U. S. in 1919, by W. W4 Adams), during the years 1916, 1917, 1918, and 1919, the metal mines of the United States worked a total of 210,548,640 shifts and had 39,705 serious accidents. During the same years, according to the following tabulation, the mines of the above-mentioned company worked 11,958,978 shifts and had a serious accident rate of 0.995 accidents per 10,000 shifts worked. If the metal mines of the United States, working these 210,548,640 shifts, had this company's serious accident rate of 0.995 serious accidents per 10,000 shifts, the total number of serious accidents would have been only 21,000 or the country's metal-mine serious accidents would have been reduced nearly one-half, and there would be 18,705 fewer serious accidents than actually occurred."

Jun 10, 1921

This report, which updates and supersedes the Office of Surface Mining's 10-year progress report published in 1987, deals with the accomplishments of the regulatory and abandoned mine land reclamation programs during the first 15 years of the Surface Mining Control and Reclamation Act of 1977 (SMCRA). Part 1 is an illustrated description of on-the-ground accomplishments; Part 2 presents statistical information for the 15-year period. The data in this statistical report are organized in two sections: national statistics and state statistics. The national statistics provide an overview of coal mining and the implementation of SMCRA since 1977. The information reported for the states presents a brief description of the coal reserves in each area, accompanied by detailed statistics and graphs that relate each state to the nation as a whole. The statistics compiled in this report are from the Office of Surface Mining's files, computer data systems, and annual reports. During the early years of the program, many of the data categories were evolving and changing; therefore, data reported over the 15-year period are not complete for all states for all years, and where data was unavailable or zero, a dash (-) is shown for that item. The data sources used to compile the tables and graphs are listed and described in detail on page 76. Due to the number of requests for this information in the past, statistical information about coal mining and its regulation will be available each year as an appendix to the Office of Surface Mining's Annual Report to Congress. Beginning in Fiscal Year 1993, this information will be compiled and published on an annual basis. For more information about this report, call or write the: Public Affairs Office Office of Surface Mining 1951 Constitution Ave., N. W. Washington, D.C. 20240 (202) 208-2553

Jan 1, 1992

By N. W. Lord

The experimental work reported upon herein was performed at the laboratory of the United States fuel-testing plant on the grounds of the Louisiana Purchase Exposition at St. Louis, Mo., between Janu- ary 1, 1905, and July 31, 1906, and was undertaken for the purpose of checking the results obtained in the routine work of the laboratory, improving the methods of working, and investigating the chemical and physical properties of coal. The laboratory having been designed primarily for the analysis of the coal samples sent to the fuel-testing plant, as well as those taken in connection with the regular testing operations of the boiler, gas-producer, and other divisions of the plant, only a very small proportion of the time of the force was available for experimental work outside of the regular routine. From the nature of such work it was not possible to separate the results obtained in 1905 from those obtained in 1906, especially as many of the experiments, such as those on the alteration of coal, involved a long time and were started in 1905 and continued to the middle of 1906. This report therefore covers all such work up to its completion in July, 1906. The complete history of the coals used in these experiments is not given, the samples being usually referred to by their laboratory num- bers only, as such information is generally not necessary and does not affect the interpretation of the results obtained in the experiments. Fuller information as to any particular sample may be found in the published reports of the fuel-testing plant for 1905 and 1906. In the following pages the results of each line of experimental work are given under a special heading indicating the object of the investigation.

Jan 1, 1911

By H. C. Howarth

The preliminary tests referred to in this report wore made at the Bureau's Experimental Mine under the general supervision of G. S. Rice chief mining engineer, to determine whether rock dust way be used to extinguish or control mine fires. DESCRIPTION OF THE DUST USED The dust used for application by hand was made from draw slate taken from the Experimental Mine. This draw slate was crushed in a hammer-type crusher fitted with 1/16 inch by 2-inch slotted screens. A sizing test of the dust showed 96.5 per cent through 20 mesh, 69.4 per cent through 48 mesh, 46.2 per cent through 100 mesh, end 33.5 per cent through 200 mesh.

Jan 1, 1927

By Richard H. Singleton

Native asphalt was produced in 1980 by six companies in four States. Leading States were Texas and Utah. Output decreased 22% in 1980 to 1.25 million tons while value decreased 2% to $25.0 million. Bituminous limestone was produced by Whites Uvalde Mines and by Uvalde Rock Asphalt Co. in Uvalde County, Tex.; by Southern Stone Co. in Colbert, Ala.; and by Barton County Rock Asphalt Co. in Barton County, Mo. The product was used mainly in street and road repair. Gilsonite was produced by American Gilsonite Co. in Uinta County, Utah, and by Ziegler Chemical and Mineral Corp. in Weber County, Utah. This material was used for purposes other than road repair.

Jan 1, 1981

By M. K. Larson, J. K. Whyatt, F. M. Jenkins

The U.S. Bureau of Mines conducted an overcore stress measurement on the 5300 level of the Lucky Friday Mine, Mullan, ID, to investigate the stress regime around an experimental stope in a rock-burst-prone mine. The result indicated a stress field with unexpected magnitude and orientation [F . 135 MPa (19,600 psi) oriented S 80E1W]. An unusual amount of rock-burst activity was encountered during subsequent excavation. A careful review of the overcore data suggested the overcore strain measurements were valid. Moreover, concentrated rock-burst activity suggested that the measured stress field did exist, but was localized and therefore did not represent the far-field in situ stress field.

Jan 1, 1995

To find solutions for common safety problems encountered in the handling of trailing cables, based on observations at many different surface mining operations. Approach Practices in handling trailing cables were Investigated through personal visits to over 40 mines, supplemented by visits to cable manufacturers and cable repair service companies. The most effective solutions to the safety problems en-countered were noted and are described In the project final report. Examples are given in this Technology News. Accident Experience Most cable-related injuries occur as a result of workers lifting, pulling, tripping, or being struck by the cable. The Table gives the frequency of occurrence for injuries reported during a recent 3 1/2 year period.

Jan 1, 1982