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By K. C. Strebig

The effect of some organic additives in diamond drilling of quartzite was investigated in the laboratory with a drill instrumented to measure the rate of penetration, the thrust, and the torque and to record each as a function of the distance drilled. A statistical plan was followed throughout the investigation, and an equation representing the bit performance was derived from the mathematical theory of reliability. The coefficient of friction in drilling increased with the use of additives, although the wear coefficient decreased. The decrease in wear associated with an increase in energy per unit volume consumed and the increase in penetration rate resulted in a net decrease in the cost per foot of drilling. A hypothesis explaining the effects achieved with the additives is given.

Jan 1, 1971

By C. E. Schmidt

Condensate waters from the Bureau of Mines Synthane process for coal gasification have been investigated by mass spectrometric methods to determine the organic contaminants. Waters from the gasification of six coals were extracted with methylene chloride, yielding 0.6 to 2.4 weight-percent extractable material. Using high-resolution mass spectrometry (HRMS), combined gas chromatography-mass spectrometry (GC-MS), and low-voltage mass spectrometry, 60 to 80 percent of the extract was found to be phenolic. About 20 organic contaminants have been identified and are present in the condensate waters from each coal gasified. The relative distribution of contaminants in the condensate water was nearly the same for the six coals gasified under various conditions; phenolic compounds were the most abundant in all cases.

Jan 1, 1974

By Homer J. Ballinger

A multiple drill carriage or "jumbo," which is believed to be unique in both design and performance, was constructed and has been in use for the past year at the Bureau of Mines experimental oil-shale mine near Rifle, Colo. This jumbo mounts four long feed percussion drills and is so designed that two men can operate all four drills. Before the jumbo was placed in operation, a minimum of eight man-shifts was required to drill 72 fifteen-foot holes in headings 60 feet wide and 27 feet high. The sane round is now drilled by two men in about 6 hours. Over 500 feet of drilling per man shift is easily and consistently accomplished. Use of the jumbo has resulted in a 75 percent reduction in drilling labor and a substantially lower drilling cost.

Jan 1, 1950

By I. S. Solet

This study, of the liquidus temperatures and densities of molten alloys of zinc and aluminum was made as part of a broader investigation on refining of scrap aluminum. One of the methods of refining involves the separation of liquid and solid phases by gravity segregation and by filtration. More accurate data were required on the liquidus temperatures and the densities of molten' mixtures of the metals than were available in the technical literature. New data on the liquidus curve were obtained by thermal analysis. The new temperatures are, for the most part) somewhat higher than those reported previously by other investigators. The density of molten mixtures of zinc and aluminum were found to be less than would be calculated by assuming that the two metals occupy the same respective molal volumes in solution as they do as pure metals.

Jan 1, 1949

By A. W. Khair, S. J. Jung

"A fundamental study of fragment size distribution and characteristics of fracture pattern is presented for the dynamic penetration of a conical bit into coal block. In this paper, damaged zones during crater formation and fragment size distribution were studied. Bit with a sharper tip angle and a smooth body configuration performed better penetration. Results suggest that in coal cutting the trend should be toward the face cleat direction using a sharper angled tip bits which consumes less energy for an optimum range of penetration depths, thus attaining maximum cutting efficiency and reducing fine fragments.1. INTRODUCTIONMuch research in the past has been done on energy requirements and mechanism of energy dissipation for ideal rock fragmentation in cutting process. However the mechanisms of energy dissipation or failure criteria for rocks in cutting process in order to evaluate the efficiency of energy requirements in specific rock fragmentation is not well understood. The formation of a crater in rock under the impact blow of a bit has been observed experimentally (Hartman, 1959). It is known that directly beneath the edge of the bit the rock is crushed into fine powder, toward the sides of the crater it chips out into relatively large fragments. (Sikarskie & Cheatham, 1973). Singh et al. (1967) investigated the cratering process under the two different conditions of static and dynamic loading. They found that the amount of energy consumed per unit volume of crater is unequal for the two different loading conditions. A complex network of fractures often extends downward and laterally into the rock below the bit. The surface of the specimens showed that the dynamic loading damaged larger area then the static loading."

Jan 1, 1989

By A. J. Strazisar

The Bureau of Mines conducted a laboratory investigation to study the effectiveness of low-pressure steam and water spray in suppressing respirable dust at the tips of a saw-type cutting wheel. Suppression efficiencies were found to be proportional to the amount of the water or steam applied at the cutter tips. For equivalent water output rates, a maximum efficiency of approximately 80 percent was reached for both steam and water spray. Results from the steam and water spray tests showed an increase in suppression efficiency with an increase in particle size of 1 to 8 micrometers. The data indicate no advantages for using steam as a dust suppressant.

Jan 1, 1972

By E. J. Matson

The Little Castle Creek chromite deposit was examined in February and May 1941, respectively, by W. O. Vandenburg and O. H. Metzger, engineers of the Bureau of Mines. The Federal Geological Survey started a magnetometer survey of the area in November 1940 and completed its work during April and May 1941. Field work by the Bureau of Mines was conducted during May and June 1941. The purpose of the Bureau of Mines investigation was to search for a continuation of the chromite mineralization. The property at one time was the largest chromite producer in California.

Jan 1, 1949

By J. Gautam, T. Ong, W. E. Wallace, M. Keane, S. Xing, J. Harrison

"INTRODUCTIONOrganics extractable from respirable diesel exhaust soot particles by organic solvents have been known for some time to be direct acting frameshift mutagens in the Ames Salmonella typhimurium histidine reversion assay (Huisingh, et al). Upon deposition in a pulmonary alveolus or respiratory bronchiole, respirable diesel soot particles will contact first the hypophase which is coated by and laden with surfactants. To model interactions of soot and pulmonary surfactant, we dispersed soots in vitro in the primary phospholipid pulmonary surfactant dipalmitoyl glycerophosphorylcholine (lecithin) (DPL) in physiological saline. We have shown that diesel soots dispersed in lecithin surfactant can express mutagenic activity, in the Ames assay system using S. typhimurium TA98, comparable to that expressed by equal amounts of soot extracted by dichloromethane/ dimethylsulfoxide (DCM/DMSO)(Wallace, et al, 1987). Here we report additional data on the same system using additional exhaust soots and also using two other phospholipids, dipalmitoyl glycerophosphoryl ethanolamine (DPPE), and dipalmitoyl phosphatidic acid (DPPA), with different ionic character hydrophilic moieties. A preliminary study of the surfactant dispersed soot in an eucaryotic cell test system also is reported.MATERIALS AND METHODSSoots D4 and D6 were collected at two different times as scrapings from the exhaust pipe of a diesel tractor-trailer immediately after the engine was stopped. Surfactant dispersions were made by ultrasonic probe sonicating 25 mg of commercially obtained DPL, DPPE, or DPPA into 1O ml of O.85% physiological sterile saline (PSS) for 10 min at 40 watts power. For surfactant dispersions, 2.5 mg soot was mixed into 2.5 ml of the appropriate phospholipid dispersion. Mixtures were sonicated by 40 watts sonicator probe for one min, then incubated in the sonicator water bath for 30 min at room temperature; the mixture was then incubated for one hour at 37C while being rotated continuously. Dilution series were made with saline. For solvent extraction, 2.5 mg soot was mixed into 2.5 ml of DCM and incubated in a sonicator water bath for 30 min at room temperature. The sample was then mixed with 2.7 ml DMSO, placed in a dry bath at 45C, and the DCM evaporated under a stream of nitrogen gas until 2.5 ml of liquid remained. Ames salmonella/microsome assay utilizing TA98 for frameshift mutation was used for mutagenicity testing, with and without S9 activation, as described by Ames et al (1975). Unfiltered sample extractions or dispersions were preincubated with tester cells for 90 min at 37C : 0.1 ml of sample was mixed with 0.5 ml of PSS, or of S9 mixture, and 0.1 ml of an overnight TA98 culture incubated samples were then added to 2 ml of top agar supplemented with biotin and a trace amount of histidine, and overlayed onto Vogel-Bonner minimal media plates. After 48 hours incubation at 37C, revertant colonies were counted. Solvent controls were DMSO, DPL, DPPE, DPPA, and saline. Positive controls were trinitrofluorenone (1 ug/plate), for samples not treated with S9, and 2-aminoanthracene for S9 treated samples (2.5 ug/plate). All samples were assayed in duplicate. Sister chromatid exchange (SCE) assay was performed, following Lett, et al (1981), using V79 cells, of Chinese hamster pulmonary fibroblast origin. Stock diesel sample suspensions were made as 10 mg soot/ml DPL suspension, or 20 mg soot/ml in DMSO. Aliquots of these soot preparations were added to 15 ml of culture medium per sample flask to result in concentrations of 25, 50, and 75 ug soot/ml medium. After 12 hours incubation, 200 ul of 25 uM 5-bromodeoxyuridine (BrdU) was added to each flask. After another 35 hours incubation, 200 ul of 10 ug/ml colcemid were added; and the cells were harvested three hours later. Cells were swollen by hypotonic saline, and fixed twice with methanol/acetic acid, and burst on microscope slides. Cells on the slide were stained with Hoechst 33258, exp"

Jan 1, 1990

By W. L. Cornell

The Missouri Pb ores are the only domestic Co resource being mined and processed for other metals; therefore, they present a viable short-term opportunity for Co production. Lead, zinc, and copper concentrates are produced from the ore. The Cu concentrate can contain up to 30 pct Co and the Pb concentrate up to 15 pct Co. Since Co is detrimental to the processing of the Zn concentrate; the remainder of the Co is rejected to the tailings. The tailings can contain as much as 50 pet Co originally present in the mined ore. Researchers at the U.S. Bureau of Mines have successfully tested on a continuous basis a process that recovers a bulk sulfide concentrate from mill tailings. The concentrate contains up to one-half of the Co and from 50 to 90 pct of the Pb, Zn, and Cu. Concentrate weight represents 10 pet or less of the total tailings.

Jan 1, 1989

By F. R. Cattoir, D. H. Baker

Fused - salt electrorefining has been successfully applied to the purification of vanadium metal . The electrolyte used in this refining technique was sodium chloride to which had been added 3 to 6 percent vanadium as vanadium dichloride . The average deposition current efficiency was 91 percent . Oxygen and nitrogen , the impurities in commercially produced vanadium metal , were reduced by two - thirds of the amount contained in the feed material . Hardness of the vanadium- metal product was reduced from an initial 97 Rockwell B ( RB ) to a minimum of 35 Rg . The reduction of these impurities markedly improved the plasticity of the final product obtained by melting the crystalline cell metal into small ingots . These ingots could be given a 99 - percent cold reduction by rolling before edge cracking appeared . Growing interest in high - purity vanadium and the industrial need for purer metals and improved alloys for use under high temperatures and high speeds have demanded the elimination and/or control of impurities . Accordingly, research to eliminate or control the undesirable impurities has been expanded .

Jul 1, 1960

By Thomas M. Barczak

This U.S. Bureau of Mines study evaluates factors that influence longwall support and strata interaction. The longwall system is composed of an immediate and main roof structure and three supporting foundations: longwall panel, powered roof supports, and gob waste. The main roof forms a structure that is generally supported by all three foundations, while the immediate roof acts as a beam that cantilevers from the coal face to the powered support. In most cases, shield loading involves a complex interaction of both main roof and immediate roof behavior and is a combination of loads produced from convergence of the main roof and displacements of the immediate roof caused by deformations of the cantilevered roof beam. Since the shield stiffness remains constant for all leg pressures and main roof convergence is irresistible in terms of shield capacity, the shield must be able to control the behavior of the immediate roof or floor structure for shield loading to be sensitive to setting pressures. If the goal is to minimize total shield loading, any active setting force must be offset by reduced passive shield loading to justify the active setting loads. Field data sumest that the typical reductions in passive loading do not justify the required increases in setting pressure in some applications.

Jan 1, 2010

By A. W. Henderson

Methods for converting WOCl4 to WCle were investigated in small-scale, laboratory apparatus to devise a method for preparing pure WCls suitable for conversion to tungsten metal. Chlorine, COCI2, and CCI4, alone and in combination with various forms of carbon, were tested as chlorinating agents at various temperatures. More than 95 percent conversion of WOCl4 to WCls was achieved with all reagents at 8000 C in the presence of activated carbon. Only CCl4 maintained its effectiveness in the absence of carbon at 800° C. The effectiveness of carbon was found to be related directly to its surface area.

Jan 1, 1968

By M. J. Ferrante

High-temperature enthalpy and X-ray powder diffraction studies were con-ducted on aluminum sulfide (Al2S3) as part of the Bureau of Mines effort to provide new data for the advancement of mineral technology consistent with environmental preservation and energy conservation. Relative enthalpies were measured with a copper-block calorimeter from 298.15 to 879 K. Tabulated values are listed for heat capacity, entropy, Gibbs energy functions, and relative enthalpies between 298.15 and 900 K. Enthalpies were also given in the form of an equation and combined with published data to calculate standard enthalpies of formation and Gibbs energies of formation for reactions of crystalline aluminum with crystalline, liquid, and gaseous diatomic sulfur. The hexagonal, rhombohedral, and cubic phases of Al2S3 were identified by X-ray powder diffraction studies, and the indexed powder diffraction patterns of these phases are given. The hexagonal phase was stable to about 852 K and was partially converted to the rhombohedral form at 879 K.

Jan 1, 1981

By W. A. Calhoun

The purpose of this investigation was to develop a procedure for removing excess iron from representative samples of bauxite ore from the Quapaw deposit of American Cyanamid Co., Saline County, Ark., in order to produce a beneficiated ore suitable for use in the alum industry, At the request of the sponsoring company, the samples were reduction-roasted at 800° C. and then magnetically separated. Although some rejection of iron was effected under these conditions, the general results were not satisfactory, A much more successful procedure, from the standpoints of both rejection of iron and recovery of alumina, consisted of a short (l5-minute), low-temperature (400° C.) oxidizing roast, followed by a 2-minute interval in a hydrogen atmosphere, then cooling to room temperature, and, finally, high-intensity magnetic separation to remove the iron.

Jan 1, 1957

By E. G. Valdez

Iron foundries that melt automobile scrap produce flue dusts averaging about 32 percent zinc and 6 percent lead. Some is sold to smelters, but because of the meager return and difficulty in handling, most of the dust is discarded. As part of the Bureau of Mines program to find uses for mineral wastes, research was initiated to develop an economical process to recover zinc and lead from the flue dust. Research encompassed the extraction of zinc and lead by fuming, leaching, and agglomeration. Controlled vacuum fuming of zinc to produce Prime Western zinc and a lead-rich residue was the most effective method for treating the dust. This process involved two distillations, or fumings, with carbon and methane as reductants, and resulted in recovery of 91.4 percent of the zinc in a Prime Western grade product, and 98 percent of the lead. Hydrometallurgical techniques involved several leaching methods, but the simultaneous extraction of iron, manganese, and copper resulted in contamination of the solution and made the zinc recovery processes too complicated. Agglomeration was done by pelletizing or briquetting the dust for possible use as feed to a zinc smelter.

Jan 1, 1975

By Fred N. Kissell

Methane flows and pressures were measured in mines in the Pittsburgh, Hartshorne, and Pocahontas No. 3 coalbeds. From the data, the permeability of each of these coalbeds was computed. It was found to depend strongly on the type of coal and on the amount of water in the coalbed, and it was found to increase with time. All of the coalbeds had a high-permeability zone adjacent to the face or rib, and the Pittsburgh bed exhibited directional anisotropy. Surprisingly, little or no overburden effect was observed.

Jan 1, 1972

By Roberta L. Hudak, Ellsworth R. Spencer, Eric R. Bauer, Adam K. Smith

The National Institute for Occupational Safety and Health (NIOSH) is conducting research with the objective of preventing hearing loss in the mining industry. Longwall mining is one sector that has received considerable attention. Studies involving the monitoring of worker noise exposures, characterizing equipment sound levels and dominant noise sources, evaluating engineering noise controls, analyzing hearing protection device (HPD) effectiveness, and testing of improved sound level monitoring techniques specifically for longwall mining systems, are being conducted. The research efforts revealed that stageloader operators are the most exposed longwall workers, with the discharge end being the noisiest location along the stageloader. In addition, the studies have shown that using stationary dosimeters, coupled with observational data of the cutting cycle and worker habits, has the potential for improved monitoring of the effectiveness of engineering noise controls. To address the ineffective use of soft foam earplugs, a simplified 3-step method was developed for inserting soft foam earplugs. Results indicate a 9 dB greater attenuation after training subjects on the 3-step method. Finally, muff type HPDs are being evaluated for effects of speech intelligibility in noise. The combined results of these studies illustrates that much can and has been done to prevent noise-induced hearing loss (NIHL) in the mining industry, especially with respect to longwall mining workers. This paper presents an overview of ongoing studies, a progress report of results, and the implications for reducing worker noise exposures and preventing NIHL in longwall mining workers.

By W. H. Eddy

The Bureau of Mines conducted laboratory batch-and small-scale continuous flotation processing tests on waste granite fines from Georgia, to determine the feasibility of recovering usable feldspar and quartz products by flotation. Two flotation methods were utilized for the removal of biotite and other iron-bearing minerals: One was in an acid-cationic circuit, and the other in an alkaline-anionic-cationic circuit. Feldspar was recovered using an acid-cationic method. To produce commercial-grade feldspar and quartz products it was necessary to employ either two sequential froth flotation circuits or one froth flotation circuit supplemented by wet-magnetic separation techniques to remove iron contaminants. Continuous flotation processing yielded a commercial-grade feldspar concentrate containing, in percent, 3.8 Na20, 5.4 K20, and 1.10 CaO, with recoveries of 77.8, 70.3, and 64.4, respectively. The feldspar tailing was high-quality glass sand containing 98.2 percent SiO2 and 0.024 percent Fe2O3. About 42 percent of the quartz was recovered at glass sand specifications. An effective separation of, potash feldspar from the bulk feldspar concentrate was achieved by batch flotation in a mineral separation cell.

Jan 1, 1974

By Richard V. Ageton

"Everyone admits that there are more accidents in metal mines than there should be but there is much difference of opinion as to the causes of accidents, whether avoidable or unavoidable, and the amount of responsibility attaching to the miner and the mine operator, respectively. However, it seems that one of the main reasons why there are so many accidents, is that there is so little general knowledge regarding their causes and costs. Some information regarding the costs and causes of metal-mine accidents is presented in this paper.The data contained were obtained from a study of the complete accident and medical reports of two large metal-mining companies, which carry their own insurance. Path maintain hospitals with competent medical attendants. One of these companies also maintains a very efficient safety bureau, consisting of a safety engineer, with two assistants who work in connection with the medical department, and with the safety committee made up from among the miners themselves.Daring the year of 1920, ""A"" Company employed approximately 900 men, and these men worked more than 270,000 shifts. There were 373 minor and major injuries, among these 900 men, hence assuming that each injured man was hurt cut once, 41 per cent of the men who worked in this mine received some kind of time-losing injury during the year. On account of these injuries the injured men lost 3731 shifts, and thus the time lost due to injuries amounted to approximately 1.4 per cent of the total number of shifts worked,"

Oct 1, 1923

By Michael J. Sapko, Samuel P. Harteis, Eric S. Weiss

The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) recently conducted full-scale explosion experiments; these experiments evaluated the strength characteristics of various seal designs used for safely isolating worked-out areas in underground coal mines. Large-scale explosion tests were conducted within the multiple entry section of PRL’s Lake Lynn Experimental Mine (LLEM) employing the only currently accepted test method endorsed by the Mine Safety and Health Administration (MSHA) for seal design in American mines. These explosion tests are labor-intensive, expensive to conduct, and can interfere with other critical underground safety and health research programs conducted by NIOSH. Therefore, the PRL has developed an alternative seal evaluation method, based on a hydrostatic pressure loading concept, that can facilitate the in-situ testing of seals in an operating mine. Two chambers within LLEM and one within the Safety Research Coal Mine (SRCM) were used for hydrostatic pressure loading various seal designs. The results from tests in these chambers compare favorably with those from the large-scale explosion tests in the multiple entries. Preliminary size-scaling relationships for predicting the strength of standard seal designs as a function of entry size is also presented. In addition to testing seal designs at the required 20 psi static pressure level, the new facilities also allow for the determination of the seal’s ultimate failure pressure. This new approach shows promise as an alternative evaluation method for improving mine sealing technologies which, in turn, will enhance the safety of the underground personnel.