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By John A. Breslin

Three scale models of coal mine entries and mining machines were constructed by the Bureau of Mines to study the effects of ventilation parameters on dust concentrations where mining personnel would be working. A one-fifth-scale model of a coal mine entry with a drum-type continuous-mining machine and a one-sixth-scale model of an entry with a twin-borer-type machine were used as well as a one-fifth-scale model of a longwall face with a double-drum shearer. Methane was used as a tracer gas to simulate respirable dust in the models. The distance of the end of the brattice or tubing from the face was found to be more important than the airflow rate for the drum-type machine. Dust reductions greater than 90 pct were shown to be possible with a secondary ventilation system used with the twin borer and a dust collector mounted on the longwall shearer. Cutting-head speed had a significant effect on concentrations at typical positions of miners with the drum-type machine and longwall shearer but not for the twin borer.

Jan 1, 1976

By John Millhiser, Stephen J. Kravits

The U.S. Bureau of Mines preproduction Wireless Survey System (WSS) and its performance during an in-mine test are discussed in this report. The WSS was developed to reduce downhole surveying time in order to increase the efficiency of drilling long horizontal methane drainage boreholes in coal. Borehole survey data are electromagnetically transmitted from the WSS7s downhole guidance probe, via the drill rod, to the uph'ole subsystem in less than 1 min per survey transmission, regardless of borehole depth. The WSS7s in-mine test consisted of providing borehole survey data during the directional drilling of a 2,538-ft horizontal methane drainage borehole in the Pittsburgh Coalbed. By considering available drilling time, which does not include hydraulic drill downtime and the time spent traveling portal to portal, 24 shifts were needed to complete the borehole. Of the available drilling time during the tcst, 50 pct of the time was spent drilling and 50 pct surveying and maintaining the WSS to keep it operational. Previous Bureau experience indicates drilling efficiency was increased 108 pct because of the WSS, in comparison with using a commercially available wire-run directional survey instrument at 10-ft intervals.

Jan 1, 1990

By T. J. Ballard, Austin B. Clayton

"INTRODUCTION The Conrad Hill mine was first opened as a gold mine about 1832 and has been operated at various times since then.The Bureau of Mines, as part of the strategic minerals program, mapped and sampled the accessible mine workings.The: work failed to reveal appreciable copper values or evidence of additional ore deposits.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 and that they make the greatest possible contribution to national security and economy. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The field work embodied in this report was under the direction of Austin B. Clayton. The final report was prepared by T. J. Ballard uncle,- the general supervision of Mitchell H. Kline, chief, Raleigh, N. C., Branch, Mining Division. Analyses of samples and beneficiation tests were made by the Metallurgical Division. ACCESS AND OWNERSHIPThe property is 6 miles southeast of Lexington, N. C., and can be reached by U. S. Highway 64, turning off at Hedrick Grove Church, and is 1 mile north from the highway on the county road. The mine is in Davidson County at approximately 35° 47' latitude and 80° 10' longitude (fig. 1).The property comprises 471 acres and is owned (1943) by the McKeeMining Co., 512 Fifth Avenue, New York City. The property was optioned to Woodrow McKay of Lexington, N. C., in 1943, who in turn subleased the property to the Robert G. Lassiter interests of Raleigh, N. C."

May 1, 1948

By C. J. Thompson

In the course of the work currently conducted by the Bureau of Mines in cooperation with the American Petroleum Institute Research Project 48 on identifying sulfur compounds in petroleum, a micromethod was developed (12)5 for catalytically removing the sulfur atom from sulfur compounds. The product is the residual portion of the molecule; the structure otherwise was unaltered except for hydrogenation of any unsaturated bonds that were present in the original compound. Positive identification of sulfur compounds isolated from crude oils is a difficult problem. Direct comparison of properties of the unknown with those of reference compounds is often impossible because of the limited number of reference sulfur compounds available. However, a relatively large number of pure hydrocarbons is available, and the conversion of the sulfur compound to a hydrocarbon enhances the possibility of identification. The technique also can be used to prepare microquantities of scarce hydrocarbons by hydrogenating compounds that are readily available.

Jan 1, 1962

By R. A. Beall

A series of 45 zirconium ingots has been cast by the consumable electrode arc melting process with the object of analyzing the effects of power input from 50 to 230 kilowatts and reduced pressure furnace atmosphere to improve the quality of regular 8-inch-diameter production ingots made thereby. Electrode consumption rate, molten pool volume, melting efficiency, sidewall quality, arc stability, and yield efficiency are considered. The use of direct current and alternating current is studied. In conclusion, reduced pressure furnace operation is shown to promote electrical efficiency, ingot homogeneity, high metal yield, and are stability. INTRODUCTION Zirconium is a particularly difficult metal to melt because of its affinity for atmospheric gases and its solvent properties when molten. In addition, zirconium sponge as produced by the boll process contains minor amounts of magnesium chloride, which cause severe spattering luring melting, because of these difficulties with zirconium, and its sister metal titanium, near techniques have been developed to permit production of commercial size ingots. Among the more promising is the consumable electrode arc melting method.

Jan 1, 1955

By J. S. Tosh

An equilibrium study of the system potassium carbonate, potassium bicarbonate, carbon dioxide, and water has been conducted with solutions of 20-, 30-, and 40-percent equivalent potassium carboaate concentrations. These equilibrium data cover the operating range of the hot carbonate scrubbing system for removing carbon dioxide from gas mixtures. Such data are necessary to establish the limits of purification and are used to design absorption and regeneration towers. Values of K in the relationship K = (KHCO3)2/(K2CO3)PCO2 were determined for higher temperatures of 70" to 140° C. and greater concentrations, I 20 to 40 percent, than employed by previous investigators. For the 20- and 30-percent concentrations, K is constant at a given temperature; thus, once K has been determined the equilibrium pressure of carbon dioxide can be calculated for any conversion. Variation of & values with changing conversion was observed with the 40-percent solutions, so that equilibrium calculated pressures are less reliable from average K values.

Jan 1, 1959

Preventive maintenance practices are listed in the manufacturers' instruction books. In general, equipment that requires frequent and extensive preventive maintenance is generally the most costly. The manpower spent on these frequent trips to remote areas is such that it is usually better to invest in a more costly system which requires little preventive maintenance. The best preventive maintenance for the system is a good installation. 7.2 Preventive Maintenance and Inspections With any system, periodic inspection is required because of the corrosive atmosphere and adverse conditions that exist in underground mines. These inspections can spot potential trouble in the system. Repair or replacement at that time averts the possibility of losing effectiveness of all or part of the system. 7.2.1 Cables Approximately once per month all cables in the communications system should be inspected for kinking, chafing, cracking, wear, stretching, or other signs of physical abuse. Particular attention should be paid to cable glands at the entry or exit points to the various units in the system, where the cable goes around sharp corners, in the vicinity of holding cleats which may be clamping the cable too tightly causing potential damage, and across the areas where the cable is exposed to physical damage from outside sources, such as equipment or falling objects. If a cable is damaged, it should be replaced as soon as possible. It is mandatory that the ground leads and connections to carrier current phones be thoroughly inspected and maintained in good condition, since considerable hazard may exist to the operator or equipment if a ground connection is broken. 7.2.2 Pager Phones The most readily available test set to determine if a pager telephone is operating correctly is the pager phone itself. The following physical check of the system can be performed at any phone station. 7.2.2a Listen Circuit Remove the handset from its cradle and listen to determine if the circuit is functional, as indicated by the presence of noise or conversation on the line. If no noise or voice signals are present at the handset receiver, take the following corrective action: 1. Operate the handset press-to-talk switch several times. Any corrosion on the contacts of this switch may cause a receiver to be temporarily inoperative. Repeated operation may clear the condition. 2. Open the cabinet and see if the battery cables are properly connected and are making firm contact. Check the handset cable and its connections in the cabinet of the pager phone, and see if there is any evidence of a break in the cable, corroded contacts, or poor connections. 3. Remove the handset receiver earpiece by unscrewing it counterclockwise (to the left), and remove the receiver from the socket. Examine the handset cavity; in some units, a patch of cotton batting or floss is used as a barrier to reduce acoustic feedback in the handset. If the cotton patch has absorbed moisture, remove it and replace with a crumpled ball of soft rubber, stuffed just far enough into the handset so it will not touch the receiver or switch terminals. 7.2.2b Page Circuit and Talk Circuit Push the page switch, squeeze the handset press-to-talk switch, and call any other phone. Release the page switch

Jan 1, 1984

By A. L. Service

The four periods of test operation described in Report of Investigations 5219 indicated that planer mining of phosphate rock was feasible. Corrective measures proposed for design deficiencies indicated in test 4 had to be evaluated, however; and, before the attempt to design a prototype production model, it was considered advisable to test the original machine under more severe operating conditions. Planer A was modified, therefore, during the latter half of 1955, and one additional period of experimental operation was conducted in the Anderson mine of the Montana Phosphate Products Company near Garrison, Mont., during the first 4 months of 1956. Test 5 was made in a stope, where the phosphate bed had been offset in a number of places by minor faults. Considerable difficulty was found in negotiating the irregularities caused by these faults, and productionwise the test was not as successful as some of the previous ones. Information obtained, however, was valuable in designing model B.

Jan 1, 1959

By M. M. Tilman

The Bureau of Mines conducted research to evaluate superplastic behavior in commercial magnesium-base alloys AZ6IA, ZK60A, ZW3, AZ3IB, ZWI, and an experimental Mg-12 pct Al alloy. Strain-rate sensitivity indices (m-values), maximum elongations, and effects of superplastic elongation on tensile properties were determined on fine-grained sheet. Inert-gas-pressure hemisphere-forming tests were conducted on selected sheet stock of the five alloys. Formability trials on AZ31B alloy sheet were conducted on industrial equipment for comparison with commercial superplastic forming of Zn-AI alloy. Closed-die-forming tests were performed on extruded ZK60A rod. All alloys exhibited well over 100-pct elongation, indicating superplasticity, at temperatures and strain rates near the maximum m-values. Tensile properties were generally reduced following 100-pct superplastic elongation, but not to an extent that would preclude use of the commercial alloys in the superplastically deformed condition. The potential for industrial superplastic forming of AZ31B sheet was indicated by hemisphere forming in the laboratory and substantiated in industrial forming trials.

Jan 1, 1982

By R. B. Tippin

Research investigations conducted on five ore samples show the applicability of heavy liquid separation (HLS) techniques to mineral processing. Under proper operating conditions, semicontinuous tests in small fluid cyclones yielded 90 percent sink-float concentrates with recoveries exceeding 90 percent on minus 35-mesh ore samples of kyanite, potash, spodumene, fluorspar, and beryl. Although none of the ores were examined in detail, their response to this novel concentration method provides basic examples that are typical of the process. Various aspects of cyclone design and operational characteristics of heavy liquid cyclone circuits were studied which demonstrated the flexibility of HLS by using multiple units connected in series. A comparison of two heavy liquid solutions, tetrabromoethane and methylene bromide, exhibited their individual advantages and limitations. Unique problems relative to this process are discussed including liquid viscosity, mineral composition of the ore, toxicity, and material handling hazards.

Jan 1, 1968

By Wesley A. Grosh

The Allah Cooper mine, in Louisa County, Va., formerly was a producer of lead and zinc. It was believed that the critical shortage of leach and zinc and the fact that some ore had been produced at this mine justified exploration of it. A preliminary examination was made on April 30, 1943, by J. E. Hill, a Bureau of Mines Engineer. Diamond drilling was done on the property from November 30 to December 18, 1943, to determine whether the sulfide body extended to depth. One hole drilled to a depth of 650 feet and located so as to cut the Allah Cooper ore shoot about 150 feet below the lowest known mine workings failed to disclose sulfide vein at that depth.

Jan 1, 1949

By Sidney Katell

This report is an economic evaluation of the production of hydrogen in a continuous system by the steam oxidation of partially reduced iron oxide in a fluidized bed at 7 atmospheres using producer gas to reduce the iron oxide. The oxidation-reduction step is based on experimental data obtained by the Bureau of Mines at the Pittsburgh Coal Research Center. The estimated capital requirement for a plant producing 30 million std. c.f.d.3 of 99.8 percent purity hydrogen at a discharge pressure of 450 p.s.i.g. is $13,100,000, using January 1961 equipment cost data. Based on a 330-day operating year, the operating cost before profit and taxes with coal price as a variable is estimated to be:

Jan 1, 1962

By Robert J. Timko

The objective of this Bureau of Mines research work was (1) to determine how well the E. I. Du Pont de Nemours and Company P-2500 personal dust sampling pump controls the flow rate at 2 L/min and (2) to compare respirable dust mea-surements made using the P-2500 with those made using a nonpulsating sampling flow system, both using the Dorr-Oliver 10-mm nylon cyclone dust size classifier. The calibrator and the operation manual for the P-2500, supplied by the manufacturer, were also evaluated. Flow tests consisted of long-term (6-to 8-hour) flow stability tests at various backpressures, a low-flow indicator examination, flow controller response time tests and pulsation tests. Dust tests were performed using coal, silica, and Arizona road dust. No tests were performed to examine effects of temperature, barometric pressure, vibration, or mechanical shock. These pumps performed well within manufacturer specifications in all tests.

Jan 1, 1982

By G. E. McClelland

During the 1970?s, the Bureau of Mines investigated a particle agglomeration technique for improving the flow of leaching solution through heaps of clayey or crushed, low-grade gold-silver ores, wastes, and tailings. This technology has been adopted on a broad scale by the precious-metals-processing industry. This report presents information on five commercial operations that have benefited from agglomeration technology and that represent a cross section of current heap leaching practice. The technology is cost effective because of decreased leach times and improved precious metal recoveries.

Jan 1, 1983

By Gertrude N. Greenspoon

Legislation and Government Programs.-The Occupational Safety and Health Administration (OSHA) held public hearings in early 1975 on proposed standards for exposure to inorganic arsenic. The findings obtained at the hearings will be considered to promulgate emission standards. Domestic Production.-Arsenic trioxide (As203) was produced domestically only at the Tacoma, Wash. copper smelter of ASARCO Incorporated. Production data cannot be published. Output rose 9% over that of 1974, shipments were less than half those of 1974, and stocks rose 31 %. Production of arsenic metal, begun by ASARCO in August 1974, continued in 1975.

Jan 1, 1977

By G. W. Murrie, W. P. Diamond, S. W. Lambert

A geologic study of the Mary Lee Group of coalbeds in the Black Warrior coal basin was undertaken to examine coal stratigraphy and determine regional trends and extent of the coalbeds. The area investigated encompasses 835 square miles in Jefferson, Walker, and Tuscaloosa Counties, Ala. More than 700 core logs were used to construct a structure map, coal, interval, and overburden isopachs, and cross sections. There is evidence that structure affected sedimentation. Coalbed isopachs indicate the Mary Lee Group was deposited in fluvial-deltaic and low-lying coastal plain environments. The Mary Lee coalbed is the only coalbed which is continuous throughout the area, commonly with two benches which have a combined thickness of 2 to 12 feet. The Mary Lee coalbed changes rank in the basin from high- through medium- to low-volatile coal. The methane gas potential of the Mary Lee Group coals is estimated to be greater than 1 trillion cubic feet. There is an excellent correlation between the orientation of surface cleats with those measured underground in the Mary Lee coalbed. The face cleats roughly parallel the axes of the area's folds and trend northeast-southwest.

Jan 1, 1976

By A. J. Kraemer

The Bureau of Mines for a number of years has been carrying on an investigation of properties of crude petroleum from producing, fields in the United States and the Western Hemisphere, and has published a series of reports on these fields, including oil fields of Oklahoma2. Acknowledgements Thanks are due to R. R. Brandenthaler and Peter Grandone, of the Petroleum Experiment Station of the Bureau of Mines, at Bartlesville, Oklahoma, who reviewed the manuscript and contributed valuable suggestions. The samples were analyzed under the direction of E. C. Lane at the Bartlesville station of the Bureau of Mines.

Jan 1, 1927

By Warren E. Morrison

The continuing high-level performance of the domestic mineral and mineral fuels industries during 1966 was sustained by the longest business upturn in the Nation's history. Spurred by consumer demand at home and the defense production requirements of the Viet-Nam war, the rising trend of economic activity during the year was reflected in the upward movements of the major economic indicators. At yearend the gross national product (GNP), representing the value of all goods and services produced, stood at $740 billion, $58 billion greater than in 1965. Corrected for price changes, the real value of GNP in terms of 1958 dollars was $648 billion and represented an annual increase in economic activity of 5.4 percent. Some 74 million persons were employed during the year out of a total population of 196.8 million, while unemployment fell below 4 percent. The Federal Reserve Index of Industrial Production averaged 156 for 1966, up 13 points from the previous year. However a jarring note in the 1966 expansion, and one which affected the mineral industries in particular, was the increasing pressure on prices and the threat of inflation. From 1961-65 economic growth was facilitated by relatively stable wages and prices and only mild inflation. During the period average wholesale prices hardly moved while average consumer prices rose only about I percent per year. But this long run of relative price stability ended during 1966 when consumer prices rose 2.9 percent and wholesale prices were up 3.2 percent from the previous year.

Jan 1, 1967

By T. A. Johnson

Recovering from low demand in 1975, raw mineral production in the United States maintained a steady climb in value and quantity throughout 1976, keeping pace with the gross national product (GNP), which increased 11.5% compared with that of 1975. The minerals industry, in the past, has met ever-increasing demand while keeping production costs to a minimum. To maintain this capability, technological research and development of more efficient processing methods must continue. The role of Government and its increasing involvement in minerals industry actions received unfavorable comment from various segments of the industry in 1976. Government pricing controls were of concern to most industrial firms marketing like products. Public land withdrawals in large blocks were of concern to the mineral industry.

Jan 1, 1978

By Verne S. Mutton, William A. Slivensky, Eric S. Weiss, Kenneth L. Cashdollar, Deepak R. Kohli

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory, cooperated with Tecrete Industries Pty. Ltd. and BHP Australia Coal in a research program to evaluate the strength characteristics and air leakage of four seal and two stopping designs for use in underground coal mines. A fundamental safety research area for NIOSH is to eliminate the occurrence of coal mine explosions or to mitigate their effects. One approach to achieve this goal is to develop new and innovative seal designs that provide increased explosion isolation protection for the mining personnel against ignitions that originate from within the gob or. other worked-out areas of the mine Full-scale seals and stoppings were constructed in the Experimental Mine at Lake Lynn Laboratory near Fairchance, Fayette County, PA. They were ail--leakage tested, then subjected to a series of explosions with average pressure pulses ranging from 25 to 500 kPa (3.5 to 72 psi). Instrumentation measured seal displacement and acceleration as a function of time, providing data to assist in the development of numerical models 1'01- future seal design. All three seals designed with Meshblock wire forlnwo~-k ant1 a lnonolithic shotcrete core withstood the first explosion test, which generated an avcr-age rnaximu~n pressure of - 140 kPa (-20 psi) while maintaining acceptable air leakage rates. These seals I-anged from 175 to 325 mm thick. They included a 2.7-m-high by 325-mm-thick seal that was tesled 27 hr after completion against this - 140-kPa explosion pressure, a special requirement of the test program. This seal survived explosions with pressure pulses up to 300 kPa (43 psi). The 2.3-m-high by 325-mm-thick Meshblock seal survived three explosion tests with overpressures up to 455 kPa (66 psi) and satisfied the air leakage criteria. A I ,200-mm-thick plug seal was constructed of two Gunmesh formwork walls in-filled with shotcrete and a 3,450-kPa (500-psi) strength Aquablend core. This plug seal survived three explosions with pressure pulses ranging 11-om 150 lo 430 kPa (-22 to 62.5 psi) with no measurable postexplosion air leakage. Two Gunmesh stoppings with thicknesses 01' 40 and 75 inln withstood explosion overpressures of 23 and 115 kPa, respectively. Anchoring all seal and stopping designs into the roof, ribs, and floor with steel "rootbolts" provided very effective boundary constraint that is critical to the performanceofstructures subject to explosion overpressures.

Jan 8, 1999