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By J. D. Hadden

The Bureau of Mines conducted drilling studies in the Pocahontas No. 3, the Pittsburgh, and a western coalbed to establish the gas migration characteristics for each. Gas pressures in the Pittsburgh coalbed were about 260 lb/in2 and in excess of 550 lb/in2 in the Pocahontas No. 3. Caving in drill holes prevented pressure measurements in the western coalbed. The Pittsburgh coalbed contained intersecting "clay veins" which formed gas pressure cells. Although these geological features hamper mining, they can be used to control the flow of methane into a mine working. Methane control techniques are proposed for the Pittsburgh and Pocahontas No. 3 coalbeds.

Jan 1, 1969

By Launa Mallett, Charles Vaught, Michael J. Brnich, R. Lincoln Derick

After thoroughly covering the health and safety training subjects required under Title 30, Part 48, of the Code of Federal Regulations (CFR), mine operators often find themselves with little or no time left in the class schedule for other important topics. This paper discusses a technique developed in partnership with RAG Twenty mile Coal Co., Oak Creek, CO, for incorporating employee participation at all levels in fire prevention and safe equipment operation training outside of traditional classrooms. The process involves development of training modules consisting of short, 5- to 7-minute videotapes coupled with toolbox talks that ground the content of the videos within the context of a miner’s workplace.

Jan 1, 2002

By L. B. Pankratz

The Bureau of Mines conducted heat-content measurements above 298.15° K for dehydrated analcite (NaAISi2O6) to 1,000°K, kaliophilite (KA1Si04) to 1,800° K, and leucite (KAlSi206) to 1,800° K. Heat content and entropy increments were tabulated, and the heat content data, were given in equation form. A first order transition was noted for kaliophilite near 810° K with a heat absorption of 160 cal/mole. Leucite had a second order transition which became complete near 955° K. In this transition a crystal change occurred from tetragonal (low-temperature form) to cubic (high-temperature form).

Jan 1, 1968

By Vijia K. Karra

Making sure workers within the aggregates industry go home safely each day is the goal of aggregate companies throughout the United States. At the National Institute for Occupational Safety and Health (NIOSH) researchers are contributing to NIOSH’s vision of safety and health through a fact-finding approach to reducing injuries/illnesses in various mineral sectors. Surveillance data from the Mine Safety and Health Administration (MSHA) has been the primary source for such analyses. It helps to focus research efforts on key machinery, workers, and their tasks. The crushed stone category referred to in this article is represented as crushed and broken stone in the MSHA database.

By Donald R. Johnson

Apparatus developed by the Bureau of Mines for thermal analysis of oil shale was used to determine the thermal properties of shortite. Dissociation of shortite near 470° C occurs as an endothermic reaction that could consume significant quantities of heat in the oil-shale retorting process that produces shale oil. The shortite dissociation products undergo other thermal reactions that would not affect the retorting process. These reactions include crystal inversions near 365° C and 425° C and melting and decomposition endotherms above 500° C. Two separate reaction route for fusion and decomposition of the shortite decomposition products are dictated by the presence or absence of CO2 around the sample.

Jan 1, 1974

By Alfred E. Schwaneke

The surface tension from 240° to 844° C and the density from 236° to 583° C of 99.999 percent purity liquid tin has been measured using the maximum-bubble-pressure method. Results for surface tension (y) show y (dynes/em) = 566.84 -4.76 X 10-2 T (° C) with a standard error of 1.9 dynes/cm. Results for density (p) show p (g/cm3) = 7.16 -6.3 X 10-4 T (° C) with a standard error of 0.012 g/cm3. Comparisons with other data found in the literature are discussed. The experimental results are considered to be as good as any data presently available.

Jan 1, 1970

By Charles L. Kimbell

The series summarizing the prices of the major nonferrous metals on the stock exchanges of the United States and the United Kingdom has been continued this year in tables 23 and 24. Time constraints have prohibited preparation of other price information that has appeared in this study in previous years. Users are urged to consult the 1993 USBM publication Metal Prices in the United States through 1991, which gives an analysis of historical price series and trends, or the 1993 edition of Mineral Commodity Summaries for current U.S. prices on non fuel commodities, and to utilize U.S. Department of Energy sources for information on fuel material costs.

Jan 1, 1993

By A. R. Rule

Research was conducted by the Bureau of Mines to develop a process for utilization of Idaho kyanite. A continuous gravity-flotation separation process was applied successfully to recover kyanite-group minerals from an Idaho ore containing about 21 percent combined kyanite, andalusite, and sillimanite. Dry magnetic separation of the concentrate resulted in a product containing about 90 percent kyanite at a recovery of 63 percent of the kyanite-group minerals in the ore, Alumina and silica analyses were within the range generally accepted for conversion to mullite, and the finished products had a pyrometric cone equivalent of more than 38. A recovered garnet coproduct may be of commercial value.

Jan 1, 1973

By J. D. Hadden, Albert Sainato

The Bureau of Mines conducted drilling studies in the Pocahontas No. 3, the Pittsburgh, and a western coalbed to establish the gas migration characteristics for each. Gas pressures in the Pittsburgh coalbed were about 260 lb/in2 and in excess of 550 lb/in2 in the Pocahontas No. 3. Caving in drill holes prevented pressure measurements in the western coalbed. The Pittsburgh coalbed contained intersecting "clay veins" which formed gas pres- sure cells. Although these geological features hamper mining, they can be used to control the flow of methane into a mine working. Methane control techniques are proposed for the Pittsburgh and Pocahontas No. 3 coalbeds.

May 1, 1969

By R. E. Perry

In connection with a program of coal research at the Southern Experiment Station the Bureau of Mines, in cooperation with the University of Alabama and the various coal operators, conducts washability studies of coal from beds in Alabama and other Southern States in which commercially important deposits occur. One of the main objectives of a washability study is to obtain technically and commercially important data necessary for determining the best methods for preparing and utilizing the Nation's limited reserves of coking coal. Such information is important to conservation because it facilitates selection of preparation methods that will provide maximum yields of coal with low ash and sulfur contents.

Jan 1, 1958

By D. R. Babich, E. R. Bauer

US. National Institute for Occupational .Safety and Health (NIOSH) researchers are conducting a Cross-sectional survey of equipment noise and worker noise exposures in the mining industry. Surface and underground limestone is one commodity recently sun eyed. The sound levels of milling and processing equipment were recorded to identify noise sources. Full-shift worker noise exposures were completed to determine the exposure of various occupations. This article presents the results o f the noise research conducted in both underground and surface limestone manes, detailing the equipment likely to cause worker overexposures, and the occupations experiencing overexposures. Implications for worker noise exposure reduction are also reported.

By Kenneth E. Hjelmstad

The U.S. Bureau of Mines (USBM) has developed an electromagnetic (EM) fire warning alarm sys-tem for underground mines. The system generates a magnetic field for through-the-earth signal trans-mission to microreceivers carried by individual miners. EM fields can induce electric currents in metallic conductors; if an EM transmitting antenna and an electric blasting cap array are too close, the field could induce a current in the blasting array and cause an unintentional initiation of the electric detonators. The USBM conducted tests that define the safe and unsafe regions for using electric detonators near the transmitting antenna of the warning alarm system. The minimum safe distance between a transmitting antenna and a blasting array is the distance where the induced electrical current in the blasting array is 50 mA, which is the safe current level specified in Federal mine safety regulations. Tests indicate that at transmitting power levels of 100-and 1,000-W, separation distances of 9 and 21 m, respectively, were required. These distances are small compared with the dimensions of a mine. Thus, the tests indicate that, with proper placement of the transmitting antenna, the warning system can be used safely in the proximity of blasting arrays.

Jan 1, 2010

By C. P. Lazzara, R. A. Franks, G. F. Friel, J. C. Edwards, J. J. Opferman

A fire detection research program conducted at the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Research Laboratory (PRL) recently demonstrated the advantage of multiple fire sensors for early fire detec¬tion and nuisance alarm discrimination in underground coal mines. As an example, research has shown that an appropriate combination of smoke, CO, and metal oxide semiconductor (MOS) sensors has the capa¬bility to detect a smoldering conveyor belt fire which produces low visibility due to smoke, but CO concentrations too low for an early fire alarm. Such a sensor combina¬tion has the additional advantage of being able to distinguish a nuisance alarm event such as those produced by diesel engines or acetylene torches from mine fire products¬-of-combustion (POC) produced by a real tire. Research has also shown that the problem of hydrogen (H2) gas cross-interference with chemical CO sensors at battery-charging operations in diesel-emissions backgrounds can be resolved with a smoke sensor and a MOS sensor sensitive to NOx associated with diesel emissions. Other underground conditions, such as rock dust, exacerbate the problems with sensors. NIOSH has developed a neural network that takes many of these variables into account as it assesses real-time sensor data to discriminate nuisance alarms.

By J. W. Thompson

CONVEYANCE OF COAL IN PLACES. Coal or other mineral in place may be granted and conveyed as land, separate and apart from that which underlies or overlies it. Board, etc., of Greene County v. Lattas Creek Coal Co., 100 Northeastern, 561 (Indiana), January, 1913. MINERALS SUBJECT OF GRANT. Coal, mineral, and stone under the surface of the earth are the subject of grant and exception, and when excepted in a deed become a separate and distinct inheritance. Gordon v. Million, 154 Southwestern, 99 (Missouri), February, 1913. CONVEYANCE BY ONE COTENANT. One cotenant of land can not make a valid conveyance as against his cotenants of the minerals therein and a right to the small timber on the surface necessary for mining purposes with easements and full rights of way over the premises by the construction of roads, tram- ways, or railroads for the purpose of extracting, storing, handling, and shipping the mineral products. Ball v. Clark, 150 Southwestern, 359 (Kentucky), November, 1912. CONTRACT OF SALE COVENANTS RUNNING WITH LAND. Where a deed was made pursuant to a contract for the sale of certain copper-mining property at an agreed price, and at the same time and as a part of the same transaction a written agreement was

Jan 1, 1913

By C. B. Manula, R. L. Sanford, R. A. Rivell

The large amount of computer code required for this simulation model dictates that reasonable limitations be placed on some of the input variables. The program permits the following maximum sizes: 1. Ten mine car stations 2. Twenty track intersections 3. Three hundred mine cars 4. Eight motors 5. One hundred profiles 6. Twelve intersections between stations 7. Forty-five profile changes between stations 8. Thirty station pairs (routes) These may be changed by the user providing the particular computer in use has available core storage. Major Array Descriptions This section is a detailed description of four of the major arrays used in the rail haulage simulator for data storage and logical control. Other arrays are used; however, they may be considered sub¬servative to the major ones. These major variables are explained on the following pages. Motor Control Array (XXXDEF). The first 99 locations in this array are arranged according to and are developed by data input. Unit conversions are made at input time which include: 1. Tons to pounds. 2. Rolling resistance in pounds/ton to percent/100. 3. Miles per hour per second (mphps) to feet per min. per minute. 4. Miles per hour to feet per minute. The following information is stored for each motor at the array

Jan 1, 1974

By J. C. Edwards, C. C. Hwang

In the design for a fire or smoke emergency, a main concern is maintaining an evacuation path that is free of smoke and hot gases. In ventilated tunnel fires, smoke and hot gases may form a layer near the ceiling and flow in the direction opposite to the ventilation stream. The existence of the reverse stratified flow has an important bearing on fire fighting and evacuation of underground mine roadways, tunnels, and building corridors. In the present study, a computational fluid dynamics (CFD) program is used as a design tool to model floor-level fires in a ventilated tunnel. The fire is simulated by a diffusion flame of propane issuing from a circular hole on the tunnel floor. The computed profiles of velocity and temperature along channel cross sections are similar to those obtained experimentally. The computed reverse-flow layer length has been correlated with a densimatric Froude number with some success. A non-dimensional parameter involving the source fire intensity is also used for the correlation. These analyses show that an appropriate ventilation air current must be maintained to provide an evacuation path from the source fire clear of smoke and hot gases. It is believed that CFD modeling, employed correctly and interpreted carefully, can be a useful design tool for fire protection.

By Robert C. Hickman

"INTRODUCTION The Cline mine has been worked intermittently for copper and gold since 1895. Scheelite has recently been detected with the aid of a ""Mineralite"" on the old waste dumps of the mine. Four diamond-drill holes were drilled by the Bureau of Mines from August 13 to September 25, 1946. Results of this drilling showed the vein to pinch at depth and to carry no mineralization of economic importance.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the 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 project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigation work, and prepares the final report. The Metallurgical Branch, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The project was under the general supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch.Acknowledgment is due Dr. Jasper L. Stuckey, State geologist, for logging the drill core and to J. B. Zadra and associates, Metallurgical Branch, College Park, Md., for analytical determinations."

Feb 1, 1948

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

A. 4 Illustrative Simulations The capabilities of the program are demonstrated by simulating various evacuation cases in different situations for a particular mine. The mine selected for the illustrative simulations is the mine I C' , as described in Section 2, chosen particularly because of availability of mine characteristic data and mine evacuation results for test drills. These evacuation results can be used to verify validity of the predictions made by the program A.4 1 Mine Characteristics A schematic diagram of the mine is shown in Figure 19. The figure shows all the major shafts, drifts, raises and stopes of the mine in the form of a network. There are four hoists, Hoist No. 1 and Hoist No. 2 are assumed to be single drum hoists and Hoists Nos. 3 and 4 form part of a double drum hoist, with Hoist No. 4 being the main hoist (master hoist) The positions of the 133 miners, typically working in a day shift of the mine, are also shown in the figure. The miners are identified by a miner number, and their total number on each level is chosen from the data on the fire drill simulated as Case No. 1 in the illustrative simulations.

Jan 1, 1976

By D. N. Nilsen

The U.S. Bureau of Mines investigated the use of unsupported liquid emulsion membranes (LEM's) for the extraction of copper from relatively dilute aqueous solutions (=0.3 and 2.5 g/L Cu), The performance characteristics of the three main unit operations of an LEM circuit (emulsion generation, metal extraction, and emulsion breaking) were assessed in laboratory-scale batch tests. In single-stage extraction tests using 2.5-g/L Cu feed solution, emulsion membranes extracted up to 94 pct of the copper from solutions without pH adjustment and 99.7 pct when the pH was maintained at about 2.5. Simulated two-stage crosscurrent and countercurrent circuits extracted all but 3 and 4 ppm of the original copper content, respectively. Extraction data from solutions containing mixtures of metals indicated a strong preference for Cu2+ extraction when oxime-type extractants were used in the LEM; however, some coextraction of Fe 3+ and Zn2+ was experienced. An electrostatic coalescer was used to break the copper-loaded emulsions for separation of the component phases. Up to 96 pct of the contained stripping solution (internal solution) containing the extracted copper was separated from the organic phase of the emulsion membrane. The recovered organic phase was recycled without apparent problems.

Jan 1, 2010

By Seth C. Schaefer

The Bureau of Mines studied the standard free energies2 of formation of ferrous fluoride (FeF2) and ferric fluoride (FeF3) with high-temperature galvanic cells employing calcium fluoride doped with 1 mole-pet yttrium fluoride as the electrolyte. A free-energy change for the cell reaction Fe (s) + NiF2 (S) = FeF2 (S) + Ni (s) together with the standard free energy of formation of nickel fluoride yields a standard free energy of formation of ferrous fluoride from the elements of ?GF° = -168.74 + 30.63 x 10-3T ± 0.41 kcal/mole (897-1,098 K). (2) Combining the standard free energies of formation of magnesium fluoride, ferric oxide, and magnesium oxide with the free-energy change for the overall cell reaction 3MgO(s) + 2FeF3 (s) = 3MgF2 (S) + Fe2 03 (S) (3) gives a standard free energy of formation of ferric fluoride from the elements as ?Gf° = -281.45 + 90.46 X 10-3T ± 0,67 kcal/mole (880-935 K). (4) Free energies and equilibrium fluorine pressures for the two univariant equilibria of the Fe-F system are tabulated and illustrated.

Jan 1, 1975