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By J. M. Oestreich

Supercritical water (sew) Is being tested for commercial use 1n several organic extraction systems but little work has been done on the extraction of metals from minerals. This lack of information prompted Bureau of Hines (BOM) research into the sew treatment of minerals. As a result, this research project is intended to serve mainly as a starting point for further experimentation. A simple flow-through reactor was built out of high pressure tubing and used to treat minerals with SCU at 400? C and 3500 to 7000 psi. The research produced four main conclusions: (1) carbonates of copper, iron, and lead convert to oxides; (2) most iron minerals showed alteration to oxides with some iron dissolution; (3) valuable trace elements including nickel, chromium, and others leached to some extent from sea minerals along with some calcium, iron, silicon, and sulfur; and (4) treatment of sulfides extracted elemental sulfur and resulted in several alteration reactions, though with the exception of cinnabar and the iron bearing minerals, the metals in sulfides were mainly insoluble. Surface alterations on many of the minerals show significant changes have occurred in the minerals even when only minor extractions were detected. These surface effects may be very important when used in conjunction with flotation processes since the sew treatment may selectively enhance or suppress a mineral's floatability.

Jan 1, 1989

By H. P. Rue

The Bureau of Mines has recently collected two samples of crude oil from wells in the Greasewood Flat, area of northeastern Colorado. Sample 31310 was taken from the Continental Oi1 Co.'s well Briggs No. 1 which came in on September 27,7.931, with a maximum production of 940 barrels per day. Sample 31311 was taken from the Reiter-Foster Oil Co.'s well Ida Johnson No. 1 which came in on August 24, 1931 with a maximum production of approximately 1000 barrels per day. These two samples of crude oil are typical "intermediate base" crude oils according to the classification defined by Smith and Lane. The characteristics of these two samples, as shown by the Hempel analyses, indicate that they are almost identical. They have a very low sulphur content, and the residuum has a low carbon-residue content which would indicate that they are excellent crude oils for refining. Crude oils yielding a residuum which has a carbon-residue content of 4 per cent or less usually make good material for the manufacture of cylinder stocks. The pour points of the samples and the cloud test of the fractions obtained from the vacuum distillation indicate that the Greasewood Flat oil contains considerable wax. The high wax content would cause some difficulty in transmitting this oil through a pipe fine during extreme cold weather.

Jan 1, 1932

By John H. Perry

The Bureau of Mines has developed several techniques for draining methane from coalbeds in advance of mining. Drilling long horizontal holes from an underground location is one such technique, which was successfully demonstrated in the Pittsburgh and Sunnyside Coalbeds. The same technique has now been applied in the Mary Lee Coal bed at Jim Walter Resources, Inc.'s No. 4 Mine, Brookwood, Ala., where two holes were drilled horizontally--one to a depth of 1,010 feet (308 m) and the other to 540 feet (165 m). The 1,010-foot (308-m) hole proved successful in degasifying a portion of the Mary Lee Coalbed. The hole drained methane for 1 year, during which time the initial gas flow of 200,000 ft3/d (5,663 m3/d) declined to 65,000 ft3/d (1,840 m3/d). Total gas production was 40 x 106 ft3 (1.1 x 106 m3). The gas was of commercial quality, with 98 pct methane and a heat rating of 990 Btu/ft3 (36.89 Mj/m3). The methane emissions from the faces of the mine section advancing into the degasified zone were reduced by 60 pet. The 540-foot (165-m) hole was terminated prematurely when it became impossible to maintain an open hole. Because of caving, very little gas was drained through this hole.

Jan 1, 1982

By J. I. Paige

The Bureau of Mines, U.S. Department of the Interior, conducts research on methods to minimize the requirements for mineral raw materials through conservation, substitution, and increased minerals and metals recovery from primary and secondary domestic resources. To further this goal, prior Bureau research had devised a pyrometallurgical technique (RI 8211) to recover metallic iron and copper from molten copper smelting furnace slags by carbothermic reduction. As a continuation of this Bureau research on the carbon injection technique, reverberatory and electric furnace slags were treated in an 800-kva electric arc furnace by simultaneously top feeding the slag and injecting coke breeze into the bottom of the molten bath. Results of the tests show that 76 to 89 pct of the copper and up to 48 pct of the iron contained in the smelting furnace slag were recovered in a metallic phase, while 56 to 82 pct of the carbon injected into the sys-tem was utilized as the reductant. Laboratory evaluation has shown that the metal product, which contains 86.9 to 95.0 wt-pct iron and 1.3 to 4.1 wt-pct copper, will be a satisfactory medium for recovering copper by cementation. The expected energy consumption for the process is 110 kwhr per ton of molten slag treated and 520 kwhr per ton of solid material charged.

Jan 1, 1982

By David C. Oyler, Paul W. Jeran, William P. Diamond

The Bureau of Mines is cooperating with the U.S. Department of Energy in a directional degasification project at the Emerald mine near Waynesburg, Pa. This project is designed to combine the highly successful underground horizontal degasification technology with surface drilling methods. The objective of this program is to demonstrate that directional drilling can be used as a technique for degasifying coalbeds ahead of mining to reduce the hazards of methane-air explosions in coal mines. The directional hole at the Emerald mine is designed to start vertically and enter the Pittsburgh coalbed horizontally. A 3-inch-pilot hole entered the Pittsburgh coalbecl at a vertical depth of 999 feet, The hole will be reamed to 8-3/4 inches in diameter, and 5-1/2-inch casing will be cemented in place. Three individual 3-inch-diameter, 3,000-foot horizontal gas collection holes will be drilled into the coalbed in a “bird foot” pattern. A corehole and vertical dewatering hole have been completed at the anticipated coalbed intercept. The dewatering hole was drilled to130 feet below the Pittsburgh coalbed, a depth of 900 feet, and 880 feet of 7-inch-OD casing was cemented in place. Seven vertical holes for monitoring the extent and progress of degasification have been drilled within the horizontal drilling area.

Jan 1, 1979

1.1 Bituminous-Coal and Lignite Dust. - Carboniferous material having a volatile ratio of 12 percent or more by weight and a fineness such that the material passes through a No. 20 sieve. 1.2 Active Underground Workings. - Underground places in which men are required to be or to pass through in the performance of normal mining operations for the production of coal. 1.3 Working Areas. - Underground areas where bituminous coal and lignite are mined, specifically: (a) Face. - The solid surface of the unbroken portion of the coalbed at the advancing end of the working place. (b) Face Area. - The working area inby the last open crosscut in an entry or a room, including the pillar being extracted or longwall being mined. (c) Room. - A place abutting an entry or airway where coal has been mined and extending from the entry or airway to a face. (d) Crosscut (Breakthrough). - Passageways or openings cut through a pillar to connect adjacent entries or rooms. 1.4 Entry. - Underground haulageways, travelways, and airways, except working areas as defined in section 1.3. (a) Active Entry. - An entry in which coal is being mined from a portion thereof or from connected sections. (b) Parallel Entry. - Usually an intake airway parallel to the haulageway. (c) Back Entry. - Usually a return airway parallel to the haulageway.

Jan 1, 1960

By R. H. Nafziger

As part of its program to help decrease the dependency of the United States on foreign imports of nonfuel minerals and to devise technology for the efficient and economic use of domestic resources, the Bureau of Mines smelted and sulfation-leached an ilmenite from northern Minnesota. The objective was to assess the feasibility of preparing chlorination-grade titanium feedstock. The concentrate was smelted with woodchips, coke, and soda ash in 91-kg-and 1-metric ton (mt)-capacity electric arc furnaces to form Ti-rich slag and commercial-grade pig iron. The slag contained from 67 to 77 wt pct titanium oxides and from 1.8 to 7.2 wt pct iron. Sulfation occurred in a 4.5-kg/h moving-bed reactor using S02-air mixtures at temperatures of 8000 to 8500 C to form soluble salts of the Ca, Mg, Mn,and Na impurities, which cause plugging of fluidized-bed chlorinators. Subsequently, the sulfated slag was leached in acid to remove the soluble sulfates. The final product from small-scale testing contained up to 95.5 wt pct Ti02, a minimum of 0.6 wt pct Fe, and a minimum total of 0.3 wt pct of the four impurities of interest. The final product meets charge specifications for chlorination. However, more large-scale testing is necessary.

Jan 1, 1987

1. Mine drainage constitutes surface or ground water which flows from mines or mine sites and is usually characterized by concentrations of acidity or alkalinity. 2. The regional geology controlling the ground water flow pattern in conjunction with the life cycle mining plan can serve as a basis for making decisions about quality of water that can be expected to be encountered. 3. In regard to the prevention and control of acid water formation in underground coal mines, much is left undone in research and education: (A) Very little literature is available on this specific subject although much has been written on water management in underground mines. (B) Little or nothing is contained in the text books and curricula used in mining departments at colleges and universities with the result that educational offerings may be seriously deficient in these areas. 4. Prohibiting water entry into underground coal mines is the best method of preventing water pollution. Since this is not possible as mining operations are extended, preventing water or oxygen from contacting acid producing material may offer the next best alternative. 5. More emphasis is needed during the mine planning stage on steps to prevent water pollution. Such life cycle considerations as type of mining, sequence of development and spatial configuration as well as the elements of the drainage network and final network organization and extent must be considered.

Jan 1, 1970

By H. H. Dewing

The Bureau of Mines conducted a laboratory-scale investigation of a technique that produces zinc sulfate and elemental sulfur from sphalerite concentrates by reaction with sulfuric acid at 175° to 200° C and ambient pressure. The objective of the investigation was to develop a hydrometallurgical method of producing zinc from sulfide concentrates that does not generate sulfur dioxide pollutants. Reaction with 80-to 85-pct sulfuric acid produced 4 moles of sulfur for every 3 moles of sphalerite reacted, with minimal production of sulfur gases under optimum conditions. More than 98 pct of the zinc was recovered as zinc sulfate after 3 hours at 175° C. The reaction mixture was leached with simulated spent zinc electrolyte containing 13-pct sulfuric acid to recover zinc sulfate from the insoluble, high-sulfur residue. Neutral zinc sulfate, which is required for electrolysis, was separated from the sulfuric acid solution by crystallization as ZnS04?7H20 at -10° C. Up to 80 pct of the water in the recycled electrolysis solution was removed by the crystallization process; evaporation was used to further concentrate the sulfuric acid for reuse in leaching sphalerite. Advantages of the proposed method over conven-tional roasting and leaching include virtual elimination of sulfur dioxide, production of a solid sulfur byproduct, and higher zinc recoveries due to elimination of zinc ferrite losses.

Jan 1, 1978

By H. Robert Ensminger

The Belizean economy had an estimated annual growth of about 3.4% over that of 1986. Economic growth during the 2 previous years was slower and was characterized by a negative trade balance. The gross domestic product (GDP) was an estimated $200 millioni2 in current dollars. Limited natural resources and scarce finances continued to make the Government's task a difficult one. Belize and China signed an economic cooperation agreement in April under which the Chinese Government is to provide technical assistance, a cash grant of $60.000, and a long-term, interest-free loan of approximately $1.5 million. In May, it was reported that gold was discovered in a remote area of the Maya Mountains in western Belize. An estimated unassayed value of $400 million has been placed on the deposit by one of its discoverers. However, the government in Belmopan has played down the discovery. Two U.S. oil companies. Seahawk Oil International of California and Alston Oil Co. of Texas, were granted licenses to explore for oil. Seahawk Oil will explore a large area of the Orange and Corozal Districts, while Alston Oil will prospect a 90,000-acre area of the western Cayo District. Another U.S. oil company, Pecten Oil Co., recently completed seismic studies off-shore of Belize City. Pecten Oil has made plans to start drilling in 1988.

Jan 1, 1989

By Leonard J. Prosser, Joseph Cervik, John H. Perry

The Bureau of Mines has developed several techniques for draining methane from coalbeds in advance of mining. Drilling long horizontal holes from an underground location is one such technique, which was successfully demonstrated in the Pittsburgh and Sunnyside Coalbeds. The same technique has now been applied in the Mary Lee Coalbed at Jim Walter Resources, Inc. 's No. 4 Mine, Brookwood, Ala. , where two holes were drilled horizontally--one to a depth of 1,010 feet (308 m) and the other to 540 feet (165 m). The 1,010-foot (3083) hole proved successful in degasifying a portion of the Mary Lee Coalbed. The hole drained methane for 1 year, during which time the initial gas flow of 200,000 ft3/d (5,663 m3/d) declined to 65,000 ft3/d (1,840 m3/d). Total gas production was 40 x lo6 ft3 (1.1 x lo6 m3 ). The gas was of commercial quality, with 98 pct methane and a heat rating of 990 Btu/ft (36.89 Mj/m3). The methane emissions from the faces of the mine section advancing into the degasified zone were reduced by 60 pct. The 540-foot (165-m) hole was terminated prematurely when it became impossible to maintain an open hole. Because of caving, very little gas was drained through this hole.

Jan 1, 1982

To improve the reliability of the Bureau developed bore-hole gage now widely used to determine the absolute state of stress in rock. Approach Use the knowledge gained by extensive field tests to design a more rugged and reliable Instrument using lighter and stronger materials. How It Works The original gage consisted of a stainless steel cylinder 1-3/8 Inches In diameter and 10-1/2 inches long. The new gage is made from titanium. This lighter material reduces the weight of the gage by 43 percent, which enhances the gage placement and depth of overcoring in vertical up? holes. For added strength, the titanium case and placement end are now threaded to the gage body instead of using screw fasteners. Three pairs of strain gaged transducers are positioned to measure the diametral deformation of a 1-1/2 diameter borehole at 60-degree intervals around the Inner surface of the borehole. Each transducer consists of a beryllium copper cantilever with a strain gage cemented on each side. These transducers are secured Into the gage body by a tapered shank for minimal creep. The transducers opposite each other are wired together to form a 4-arm external bridge circuit. A pair of transducers is referred to as a component. Any deformation of the borehole, which occurs during overcoring, is detected by pistons which translate the motion to the components. Each

Jan 1, 1982

By Harry E. Tufft

Data were obtained by the writer from a number of the large coul-mine operators in Illinois, on the consumption and cost of timber used in their mines and the quality of the timber now being used as compared with former years. This information supplemented by comparative date for previous years published in bulletins of the filinois Coal Mining Investigation series, and other sources, is presented below. This survey is part of a cooperative study with the . S. Forest Service, of the mine timber situation, with particular regard to the economies to be derived by better selection, preparation, and storage of timber, and especially treatment with preservatives to prolong the life. Geo. S. Rice, chief mining engineer of the J. S. Bureau of Mines, under whose general direction the work was done, gave valuable advice and criticism. R. B. Miller, State Forester, contributed helpful data which he had recent- ly obtained in an independent study of the mine-timber situation in Illinois.

Apr 1, 1923

By John J. McClelland, Gerald T. Homce, John R. Thalimer

The U.S. Bureau of Mines has investigated the early detection of insulation failure in squirrel cage induction motors for the past 4 years. Research was done using a sophisticated empirical data-modeling technique based on values calculated from a motor's voltage and current phasors. This technique produces two polynomial equations that calculate the insulation leakage current and power. These models were implemented in a prototype system that monitors six motors on a continuous miner for insulation leakage. These insulation leakage values are used to anticipate insulation failure. The system consists of a motor-data-system for each motor on the machine and a control computer located away from the miner. Each motor-data-system consists of an analog interface to the motor's voltages and currents, a single-board computer that reads digitized data and calculates voltage and current phasors, and a bus node that interfaces the single-board computer with the rest of the system by way of a serial bus system. Using this bus system, the control computer requests and receives phasor data from the motor-data-systems. From these data the control computer calculates and displays two deterioration values for each motor, for leakage current and power, using Bureau-developed models. These values are stored in a data base from which the user can display graphs of each motor's deterioration values over time.

Jan 1, 1992

By Dave P. Cooper, Tim D. Burgess, Dean H. Ambrose

This paper discusses the application of digital human models (DHM) to examine computer generated forces necessary to move specific joysticks by using roof bolter virtual operators to predict the forces experienced on the operator’s upper extremities. Using DHM and simulations of static movements, investigators analyzed predictions of joint moment and joint force effects on virtual operator’s right wrist, elbow and shoulder and compared them to different body dimensions and work postures. This study exemplifies the ease of estimating upper extremity loads on equipment operators using virtual operators and computer models of equipment and work environment. As expected, comparing results of percentage of joint force and moment reduction using the electronic control and of the mechanical control showed that the electronic control had lower joint forces and joint moments over the mechanical control. The average predicted value of the joint moment on the wrist was 1.84 Nm, elbow 7.85 Nm and shoulder 14.55 Nm and of the joint force on the wrist was 5.06 N, elbow 4.56 N, and shoulder 3.67 N. Because the data illustrates low-level forces to move a joystick, inadvertent actuation of the control is addressed. Regardless of the findings, research is still needed on joysticks in real world situations such as an epidemiological assessment of equipment operators in the field before final recommendations and conclusions can be drawn.

Jan 1, 2007

By Thomas V. Falkie, R. Venkataramani

1. Summary This investigation is concerned with description of the loading function at the underground coal face, and the identification of varia¬bles - geological, geometric, mechanical, and operational - that affect the loading function. The immediate objective of this work was to provide information for operations-research studies as applied to underground coal mining, and the broad objective was to provide guide¬lines for planning and equipment selection in underground coal mining. The loading function was expressed as -a statistically-developed linear mathematical model. Originally, fifteen independent variables were considered which potentially could have influenced the loading function. These variables were constructed on the basis of measurable or estima¬ble geometric and geological properties at the working face, mechanical characteristics of the mining machine, and certain operational proce¬dures of mining. The original model explained 64.0 percent of the experimental variation. The final condensed model explained 54.1 percent of the experimental variation in terms of only five indepen¬dent variables, namely: 1. Ratio: width of cut/total width of cutter 2. Ratio: height of cut/diameter of cutter 3. Total horsepower of cutter-drive motors 4. Rotation speed (RPM) of cutter 5,. A subjective estimate of machine quality and operator skill Certain limitations were found to exist in the evaluation of the variables. Principle among these limitations was the impossibility of precise measurement of tonnage loaded in certain instances.

Jan 1, 1972

By E. P. Youngman

The mining laws referred to by those who furnished the reports mentioned in the preceding paragraph are : General Austrian Mining Law of 1854 and the Law of 1868 , which prescribes for Hungary (as well as for Transylvania ) the full text and decisions of the General Austrian Mining Law; Government Decree 18346 , 1859 ; Parliamentary Decree of 1861 ; the Law of 1871 ; the Commercial Code , Law 37 of 1875 ; the Industrial Lar of 1884 ; the Law of 1386 ; the Decree of the High Court of Justice , 5540 , of 1399 ; Laws 6 and 7 of 1911 ; Law of 1921 ; Laws 23 and 24 of 1922 ; Laws 5 and 21 of 1927 ; and Law 40 of 1928. ( Lev 21 of 1927 and Law 40 of 1928 are labor laws . ) A compilation of the mining laws of Hungary , " Magyar Banya Jog , " or the " Hungarian Mining Law, " was made use of in part . This volume is the second edition of a school textbook , which ras prepared by Dr. Bela Balkay and Dr. Imre Szeoke , and which was published by the Apollo Press ( V. , Sas -utca 13 , Budapest ) in 1909 .

Jun 1, 1931

By Brian White, Hamid Maleki

Sudden, violent failures of rock around mine openings influence access, ventilation, and safety in both hard-rock and coal mines. To develop predictive tools for assessing the potential for violent failure, the authors initiated a comprehensive study using (1) multiple linear regression and numerical modeling analyses of geological and mining conditions at 25 sites to identify the most significant factors contributing to stress bumps in coal mines and (2) investigations of the geological and mining factors contributing to rock bursts in the Coeur d'Alene Mining District of northern Idaho, particularly the influence of preexisting structures on rock bursts. Twenty-five factors were initially considered in the study of coal bumps. The most important variables were identified as (1) mechanical properties of strata, (2) gate road geometry and/or gate pillar factors of safety, (3) roof beam thickness, joint spacing, and stiffness characteristics, and (4) stress gradients associated with previous mining and anomalous geologic conditions. In the Coeur d'Alene district, burst damage related to preexisting structures results primarily from (1) sudden buckling and crushing of rock layers where surfaces of development and production openings lie at low angles to bedding, faults, or other planar structures and (2) disturbance of loose ground caused by seismic fault-slip on preexisting faults or previously sheared bedding planes that intersect veins near pillar-stope margins.

By G. R. Peterson, K. E. Porter

The U.S. Bureau of Mines has estimated the potential availability of copper from 204 mines and deposits in market economy countries (MEC's). The evaluated properties have demonstrated resources totaling 436.4 million metric tons of contained copper and account for 90% of the Bureau of Mimes reserve base for copper in market economy countries. Total recoverable MEC copper resources are 340.8 million metric tons, 69% of which is from producing mines and 31% from nonproducing mines and deposits. Chile had the lowest estimated average total cost from producing mines of W.48 per pound of recoverable copper at a 0% discounted cash-flow rate of return (DCFROR), with estimated average total costs ranging from $0.40 to $0.81 per pound. The estimated average total cost of production, per pound of copper, for producing mines in the United States amounts to $0.57 in January 1988 dollars at a Wo DCFROR, with estimated total costs ranging from $0.36 to $0.85 per pound. In both real and nominal terms, the United States has, on average, significantly lowered its copper production costs since 1981. Rationalization of the industry and significant increases in productivity have made a strong improvement in the competitiveness of the U.S. copper industry to the extent that the United States should no longer be considered as a marginal producer of copper.

Jan 1, 1992

By John T. Aydelotte, Martin J. Gavin

" Oil shale contains little or no oil as such , but it contains an organic material from which oil may be produced by destructive distillation" . This statement , or others conveying the same meaning, appears in many popular and techni cal articles on oil shale . It is based on the belief that the ordinary solvents of petroleum have but little action on the organic substances contained in oil- yielding shales , although on distillation these same shales may yield upwards of 50 gallons of crude shale oil per ton . A 50 - gallon shale thus yields by distillation 18.73 per cent of its weight as oil ( assuming the specific gravity of the oil to be 0.900 ) , although only a relatively small part of this can be recovered by extraction with such solvents as chloroform , carbon tetrachloride , and the like . In the course of certain experiments designed to determine the solubilities of different shales after they had begun to yield oil by distillation , it was found desirable to determine the quantity dissolved from certain unheated shales by various solvents , at or near the boiling points of these solvents . The method used and results obtained are presented below. These experiments were made in connection with the oil - shale investigations being conducted by the U. S. Bureau of Mines , in cooperation with the States of Colorado and Utah .

Jan 1, 1922