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By Homer J. Ballinger

The Rex mine is one of several zinc deposits in Ozark and Howell Counties, Mo. It is the second of these deposits investigated by the Bureau of Mines in an effort to demonstrate reserves of sulfide ore underlying the shallow carbonate ores from which the district's major production has come. The initial investigation was made during 1945-46 on the Alice mine, Ozark County, Mo.21 The investigation reported herein was conducted during 1947. The Rex open pit is about 250 feet long, 100 feet wide, and about 25 feet deep (average). Three caved shafts are evident in the bottom of the pit, but the extent of the workings from these shafts is not known. The Bureau of Mines drilled five churn-drill holes in and around the Rex pit to test the grade and the vertical and lateral extent of the deposit. Two of the holes indicate notable zinc mineralization ranging from less than 1 to more than 10 percent metallic zinc, but largely in the oxidized condition.

Jan 1, 1948

By J. B. Littlefield

[At B. meeting of the Subcommi ttce on Chemica.l _ et.lOds of Air Ant:..1ysis of-the American Public Health Ascociation in October 1937, the llse of the impinger for collectinG lcs.d fu.l1e wa:., discussed. The Bureau of \~nes de-cided to obtain infornw.tion on the efficiency of the lerge and midget im-pingers for this purpose y using the electric recipitator as a r?ference ]

Jan 1, 1938

By K. C. Dean

A semiquantitative test for the presence and identification of cesium and rubidium in rocks, clays, and mineral waters has been developed by the Bureau of Mines. The test can be used in the field, as a guide for the prospector, geologist, or mining engineer engaged in location or development [w]ork. It comprises two simple spot tests of a solution prepared from the [m]ineral sample. Phosphomolybdic acid, added to a drop of the test solution, [d]etects cesium, rubidium, and potassium in quantities as low as 60 parts per [m]illion. Silicomolybdic acid, added to a second drop of test solution, enables the operator to distinguish between cesium and/or rubidium and potassium. Test procedures, equipment requirements, and limitations of the method are described in this report. Cesium and rubidium were discovered in 1860 and 1861 by Bunsen and Kirchhoff with a spectroscope. The elements usually occur together, particularly in granite and granitic pegmatites. Rubidium does not occur as an essential constituent of any known mineral, yet it is found as a minor element in so many minerals that rubidium is 16th in abundance in the earth's crust. Cesium, which ranks as the 37th most abundant element, is the principal component of pollucite and a minor element in a wide variety of minerals.

Jan 1, 1960

By J. A. HUFF, V. V. BAKER

This circular contains a statement of the statutory provisions of the several States regarding the appointment , qualifications , and remuneration of State mine inspectors . States have been omitted where no specific provision has been made by the State law for mine inspectors .

Jul 1, 1931

By R. W. Dalzell

The performance characteristics, efficiency, and operating pressure of jute line-brattice systems were studied under varying underground conditions; various fabric grades and installation methods were used. The test results indicate that line-brattice system efficiency is dependent upon the method of ventilation the method of installation, porosity of fabric, and size of tight rib area.

Jan 1, 1966

By Helen W. Lang

This report describes a monitoring system applied by the Bureau of Mines to provide rapid, continuous determination of the main constituents of exhaust gas during the Bureau's approval schedule testing of diesel engines for under-ground use. Commercially available continuous analyzers with strip chart readout are employed for nitric oxide (mass spectrometric), carbon dioxide (nondispersive infrared), methane (NDIR), carbon monoxide (NDIR), and oxygen (polarographic). Good correlation is obtained between the continuous instrumental results and those obtained by batch chemical and gas chromatographic methods.

Jan 1, 1969

By J. E. Pahlman

The Bureau of Mines performed research on a fluid-bed magnetic roasting process for nonmagnetic taconites that utilizes low-rank coals and lignites as reductants and fuels. Roasting tests on a Michigan nonmagnetic taconite were conducted at 600° to 725° C with lignite or subbituminous coal as reductants. Partial combustion of the reductant reduced the amount of heat externally applied to the reactor to maintain the desired reactor temperature. Cleaned, dried reactor top gases were recycled to recover a portion of the reducing potential in these gases without adversely affecting concentrate grade and iron recovery. Highest iron recoveries for magnetic concentrates were obtained at a roast temperature of 650° C with lignite and at a roast temperature of 725° C with subbituminous coal. Magnetic concentrates were obtained that were comparable with commercial concentrates.

Jan 1, 1976

By Harold E. Marr

The Bureau of Mines evaluated two drill-hole probes for the delineation of Missouri lead ores. The battery-powered, portable instruments, weighing less than 30 pounds, were designed for logging holes of 1.8 inches in diameter or larger. These probes have dual scintillation detectors, balanced filters with a pass band for lead Ka radiation, and a cobalt-57 source of radiation. The results of field tests in Missouri confirm laboratory tests indicating that probe response can be correlated to lead ore grade using counting times of 10 seconds or less at any selected depth in the hole.

Jan 1, 1972

By K. C. Dean

Time and motion studies were made by the Federal Bureau of Mines on the hand and machine dismantling of scrapped auto starter motors, generators, and alternators for recovery of copper, aluminum, and iron. The studies showed that an individual with power handtools and convenient access to a hydraulic press, power bandsaw, acetylene torch, and power lathe could, in an 8-hour day, disassemble about 100 starters, or 150 generators, or 30 alternators. The scrap copper yield would be 280, 390, and 45 pounds, respectively, and the iron yield would be about seven times the copper weight. About 100 pounds of aluminum would be obtained from the alternators.

Jan 1, 1976

By R. O. Dannenberg

This Bureau of Mines report describes the results of research to develop a process for recovering additional beryllium from a commercial mill waste product, fluoferrate leach residue. Forty-five percent of the total beryllium in the leach residue was recovered in a beryllia product assaying over 98 pct Be0 by a process comprising (1) leaching with 1 N sulfuric acid, (2) adjusting the acidity of the leach liquor to pH 2, (3) extracting the beryllium with di-2-ethylhexyl phosphoric acid (EHPA), (4) stripping the loaded extract with sodium hydroxide solution, (5) boiling the sodium beryllate strip solution to precipitate beryllium hydroxide, and (6) calcining the beryllium hydroxide. Calculated reagent requirements per pound of Be° recovered by a proposed flowsheet were 28.1 lb sulfuric acid, 0.04 lb flocculent, 0.15 lb EHPA, 0.06 lb isodecanol (IDA), 0.22 gal kerosine, and 6.3 lb sodium hydroxide.

Jan 1, 1966

By D. J. Bauer

A primary amine extraction system was investigated for fractionating a cerium-group, lanthanide sulfate mixture. Addition of diethylenetriaminepenta-acetic acid (DTPA) to the amine extraction system resulted in separation factors as high as 5.4 for lanthanum-cerium, 8.0 for cerium-praseodymium, 3.7 for praseodymium-neodymium, and 7.0 for neodymium-samarium. In multistage studies on a cerium-free lanthanide mixture, 96 percent of the lanthanum was recovered with a purity of 95 percent.

Jan 1, 1968

By B. W. Naugle

This report describes the carbonizing properties of coals from the principal beds in Cambria County, Pa. Samples of coals from Upper and Lower Freeport and Upper and Lower Kittanning beds having estimated minable reserves of 50-million tons or more were studied by the Bureau of Mines. Cambria County coals rank either as medium-or low-volatile bituminous. A preparation study indicated that all coals tested in this county, except one sample from the Lower Freeport bed, were responsive to cleaning and would yield a product with satisfactory chemical properties for metallurgical coal. All coals tested from Cambria County yielded strong coke; however, they expand excessively when carbonized singly, and should be used only as minor constituents in metallurgical coking blends when carbonized in slot-type ovens.

Jan 1, 1959

By R. Barany

The heats of formation of anhydrous ferric sulfate and anhydrous indium sulfate were determined by solution calorimetry. At 298.15° K the heats of formation from the metal, rhombic sulfur, and oxygen were -615.6 ±O.7 kcal/mole for ferric sulfate and -649.6 ±O.6 kcal/mole for indium sulfate. Heats of decomposition at 298.15° K are given for the reaction that forms metal oxide, sulfur dioxide, and oxygen) and for the reaction that forms the metal oxide and sulfur trioxide.

Jan 1, 1965

By Mark S. Sanders

Based on laboratory tests and preliminary field tests of off-the-shelf steel toed rubber boots, a molded sole design was developed to provide increased traction over conventional calendared sole miners' boots. The pattern provided sharp edges perpendicular to both lateral and fore-aft slip vectors. The sole was designed to reduce mud caking. An instep lace-up capability was added to better secure the foot inside the boot. A five month field evaluation compared the prototype boots to the boots the participants usually wear. Although objective slip and fall data showed no significant advantage for the prototype, subjective evaluations made by the participants indicated increased traction for the prototype boots. Approximately 75 percent preferred the prototype to their own boot. Approximately one-third used the lace-up capability. It was concluded that molded soles provide better traction than calendared soles for the underground mining environment.

Jan 1, 1982

By C. Özgen Karacan

Methane emissions from a longwall ventilation system are an important indicator of how much methane a particular mine is producing and how much air should be provided to keep the methane levels under statutory limits. Knowing the amount of ventilation methane emission is also important for environmental considerations and for identifying opportunities to capture and utilize the methane for energy production. Prediction of methane emissions before mining is difficult since it depends on a number of geological, geographical, and operational factors. This study proposes a principle component analysis (PCA) and artificial neural network (ANN)-based approach to predict the ventilation methane emission rates of U.S. longwall mines. Ventilation emission data obtained from 63 longwall mines in 10 states for the years between 1985 and 2005 were combined with corresponding coalbed properties, geographical information, and longwall operation parameters. The compiled database resulted in 17 parameters that potentially impacted emissions. PCA was used to determine those variables that most influenced ventilation emissions and were considered for further predictive modeling using ANN. Different combinations of variables in the data set and network structures were used for network training and testing to achieve minimum mean square errors and high correlations between measurements and predictions. The resultant ANN model using nine main input variables was superior to multilinear and second-order non-linear models for predicting the new data. The ANN model predicted methane emissions with high accuracy. It is concluded that the model can be used as a predictive tool since it includes those factors that influence longwall ventilation emission rates.

By C. W. Smith

The Bureau of Mines conducted laboratory-scale beneficiation tests on a sample of corundum gneiss from Montana to devise a method for beneficiating corundum for use as a substitute for refractory-grade bauxite. A flotation process utilizing petroleum sulfonate as the collector in an acid circuit was devised. Results showed that two flotation schemes each produced a concentrate exceeding the national stockpile specifications for calcined bauxite. From a feed containing 28 pct corundum concentrates containing up to 92.5 pct alumina (A1203) were produced with a corundum recovery of 78.5 pct.

Jan 1, 1987

By Howard E. Parkinson

In 1969, new coal mine health and safety legislation was enacted in the United States. As a result of this legislation, the Department of Interior, Bureau of Mines has carried out communications research aimed at developing whole mine communications for increased safety and efficient operation. The research has advanced and many promising results are now being demonstrated to the mining industry. However, there remains a challenge to further improve wireless communications within the mine workings, and through the overburden above the workings. The objectives for future research and development will be discussed, together with the physical and operational constraints that new mine communication systems must face.

Jan 1, 1973

By J. D. Spagnola

The Bureau of Mines conducted research to obtain comparative data on the extent of reduction of galena and sphalerite with molecular hydrogen and with hydrogen from the thermal cracking of ammonia and methane at various time intervals. Galena reductions of 95 to 99 percent were obtained with H2 and with decomposed NH3 while reductions of 70 to 80 percent were obtained with cracked CH4? Sphalerite reductions of 99 percent were obtained at 1,000° C with Hz and with decomposed NBs; however, complete volatilization of the free zinc from the remaining concentrate and the subsequent recombination of zinc and sulfur vapors resulted. A promoted iron catalyst brought about a decrease of 100° C in the temperature required for complete decomposition of ammonia. It was found that H2S retards NB3 decomposition and that nitrogen retards the reduction of galena by H2? A mixture of N2 and He in about the same ratio as that obtained by the thermal cracking of NBs gave about 15 percent less reduction of galena than was obtained with decomposed NB3; this indicates that a portion of the hydrogen obtained by NBs decomposition is in an active form.

Jan 1, 1965

By K. K. Kelley, L. B. Pankratz

The heat contents of four silicate minerals -- akermanite , cordierite , gehlenite , and merwinite --were measured from 298 ° to around 1,700 ° K by the dropping method . The results were compiled into tabular and equation forms suitable for thermodynamic calculations . The heat contents of these compounds are nearly additive with respect to their constituent oxides .

Jan 1, 1964

By Erica E. Hall, Robert H. Peters, Charles Vaught, Jon C. Volkwein

Coal Workers Pneumoconiosis is the leading cause of death due to occupational illness among coal miners. This disease is caused by miners’ exposure to respirable coal mine dust. A Personal Dust Monitor has recently been developed to provide near real time feedback to miners regarding the number of milligrams of respirable coal mine dust in the air they breathe. This paper was prepared by the National Institute for Occupational Safety and Health to document coal miners’ reactions to this new device, and how they make use of the information it provides. Structured interviews were conducted with 30 coal miners at four mines. A four-stage conceptual model of miners’ decision processes with respect to how they interpret and respond to the dust exposure numbers from their personal dust monitor is proposed. The stages are: Diagnosis, Action Planning and Intervention, Evaluation, and Institutionalization. The interview responses provide considerable support for the model. Most miners paid attention to Personal Dust Monitor feedback and made efforts to reduce their dust exposure. Their efforts included: changing where they positioned themselves, making ventilation system improvements, and using respirators more often. The 29 miners who reported having experience wearing both the old and new type of dust monitors were asked which dust sampling system they preferred. Eighteen (62%) preferred the new monitors, 7 (24%) preferred existing monitors, and 4 (14%) had no preference. The most frequently cited advantage of the new monitor is its ability to provide relatively quick feedback on dust exposure. Miners provided several suggestions for improving the design of the instrument.