Search Documents

By Fred C. Turin, Lisa J. Steiner, Kim M. Cornelius

Like many experienced workers, remote control continuous miner operators perform their everyday jobs making choices and decisions that they may not consciously think about. While performing tasks, they are continuously processing feedback and cues which guide them for the next move. Initial training teaches the operators the tasks necessary to operate the equipment and perform the job. However, with experience they are better able to deal with hazardous conditions and non routine situations. To better understand what potential cues and feedback help to guide the operators, a questionnaire was developed to learn what factors affect decisions. Operator responses address issues related to specific tasks, equipment operation, visibility, lighting, and communication issues. The information collected is useful to understand what cues experienced operators use to make task performance decisions. Results will be used to develop interventions and training for safe and effective operator performance.

To determine the relative permeability of the soil a series of percolation tests were performed at the three locations of interest at Lanse, i.e., 3C, 03A and strip bank, and KA and KB at Kato. Soil cores were removed to 2, 8, 16, 24 and 32 inch depths with the thin wall sampler tube, each core separated from the next by about fifteen feet. Then two-foot-long thin-wall tubes were inserted into the 2, 8, and 16 inch deep holes and three-foot long tubes were inserted into the 24 and 36 inch deep holes. Each tube was tamped down about one inch further to assure a bottom seal; the tubes were filled with water and the rate of fall was measured. The test is similar to those done for septic tank percolation studies 6; but is not quantitatively related to Darcy's coefficient of hydraulic conductivity because the water can flow in three dimensions from the bottom of the tube. The measurements are dependent on the length of test, since the rate of fall is a function of the head. Therefore, it should be noted that the 24 and 32 inch deep tubes should give faster percolation rates because of the one foot greater head. At locations 03A and 3C the data show a sharp decrease in percolation at increasing depth, Table XV. However, the percolation at 03A and 32 inch depth is much higher than at 3C (0.2 vs. 0.01 inches/hour); the fragipan layer must be deeper at the 3C location since this area does experience a perched water table. On the strip bank the rates of falling head are randomly variable, appearing to be as much dependent on the particular location of insertion as on depth of placement. For example, water drained from the 16 inch tube as fast as it was added, probably into a sub-surface cavity or crevice. At Kato the tubes were more difficult to place because of interference of tree roots. For this reason 2 inch deep tubes were not inserted. These short tests at Kato were inconclusive, varying extensively when the tubes were moved. Field permeability tests were also performed in two (previously described) eight-inch diameter permeater tubes at Lanse and one at Kato. Because the soil is confined inside the tube, hydraulic conductivity can be calculated according to Darcy's flow equation. The high values reported in Table XVI experienced when the tubes were rewetted from a dry surface condition, enable us to conclude that infiltration is faster than the saturated permeability of the soil. In contrast to the falling head percolation tests, these permeability results do not show a high variation between locations.

Jan 1, 1972

By R. V. Thurston, Edmund S. Leaver

"During the development of the sulphur dioxide leaching process for the treatment of ""mixed"" copper ores at the Southwest experiment station of the Bureau of Mines*** the pulp from treatment of roasted cupriferous pyrite with sulphur dioxide gases and water showed an unexpected amount of sulphuric acid. After following out several false premises it was found that this was due to iron in the solution, and also that this iron tended to oxidize to the ferric state if the concentration of sulphur dioxide in the roaster gases used did not rise above a certain figure. While the percentage of iron present was email it was enough to cause an entirely different set of conditions from those of the original sulphur dioxide leaching process and to promise a much wider application of the general idea. Sulphurous acid dissolves only certain copper minerals, sulphuric acid solutions certain additional minerals and ferric sulphate solutions certain further additional copper minerals, so this observation was of importance in connection with possibilities in the hydrometallurgy of the so-called ""mixed"" or partly oxidized copper ores.The work has been carried along by a number of experimenters. L. R. Eckman, junior chemist of the Southwest station, contributed largely to the early developments. L. Roberts, W. D. Bonner and C. G. Maier each in turn physical chemists at the Pacific Experiment station, (Berkeley, Calif.) have studied the reactions involved. A complete report of all the work on this process will be prepared later under the direction of O. C. Rolston. The purpose of the present paper is to place a summary of the more practical phases of this seemingly important piece of work before those interested."

Dec 1, 1923

By R. H. Storch

This report describes work done as part of a Bureau of Mines program to appraise the titanium-mineral resources of Idaho. The work included both field reconnaissance and a spot churn-drilling program. Much general information was available, as a result of earlier work done under the Western Radioactive Minerals Exploration Program conducted between 1950 and 1954 by the Bureau of Mines for the United States Atomic Energy Commission. This particular exploration provided data as to the quantity of ilmenite (TiFe03) and accessory black-sand mineral concentrates in a number of placer deposits; however, at that time no tests were made to ascertain if the ilmenite was of marketable grade. The spot churn drilling was begun in the Gold Fork area of Long Valley, Valley County, Idaho (fig. 1), in August 1956 and was completed during October of the same year. Eleven holes (designated as the GF series on fig. 2) 35 to 45 feet in depth, aggregating 425 feet, were completed during this period. Data from other exploration drilling in 1951 was used in this report. The 13 holes in the G series shown in figure 2 were drilled by the Bureau of Mines for the United States Atomic Energy Commission; the 7 holes of the DH series were drilled by the Bureau of Reclamation. The 20 holes, ranging from 16 to 140 feet in depth, totaled 1,625 feet. The combined number of all samples recovered was 422. Those taken in 1956 were composited for each drill hole and sent to the Bureau of Mines laboratory in Albany, Oreg., for analyses.

Jan 1, 1958

By Richard A. Andre, R. Larry Grayson, Thomas Simonyi

"INTRODCICTIONThe search for the cause(s) of coal workers' Pneunoconiosis continues despite the vast amount of research that has been undertaken over the past forty to fifty years. Good correlation between the mass of dust inhaled over workers' lifetimes and the incidence of the disease has led to the development of effective environmental standards and implementation of good procedures for the control of dust generation and dispersion in the working place. Research has only begun, however, to uncover the biochemical mechanisms involved in initiating the disease.Correlation between the rank of the coal seam in which miners worked and disease incidence and severity is acknowledged worldwide, but the agents in the higher rank coal seams which cause CWP arc still not defined. The basic components of the coal seams, i.e., the elements and minerals, are generally known, but the way in which they interact with human pulmonary cells is largely still a mystery.The process of disease development is a biochemical one which depends on the characteristics of the pulmonary cells within their immediate biochemical environment and the characteristics of invading respirable coal mine dust particles, probably both chemical and physical ones. The cell-particle relationship, therefore, must be defined, and both cells and particles must be characterized according to properties which potentially are involved in the disease process.Following such characterization, specific respirable dusts from different coal seams, which appear to have different effects on coal workers, must be obtained or constructed and then used in experiments designed to determine dust toxicity or the response of animals exposed to the dusts.The results presented here focus on characterizing properties of respirable coal mine dust particles collected from operating longwalls in West Virginia and Virginia Longwall panels were selected for analysis because the respirable dust in the coal face areas is largely uncontaminated by rock dust and analysis of the dust yields results unconfounded by rock dust."

Jan 1, 1990

By Oliver Bowles

"A New Mica Company in China A report has been received from the American Consulate at Chungking, China, to the affect that a new company has been organized to operate a mica mine north of Ta-chien-lu, in the province of Ssu-Chuan. The company, which is entirely under Chinese management and control, has a working capital of $10,000. While comparatively new, the mine has been worked before, and apparently with some success. The mica is said to be of good quality. It is claimed that the deposit will supply a limited amount of mica that will cut in pieces a foot square or over, and larger quantities of smaller sizes. The chief difficulty is transportation, for it is reported that a ten days' journey, part of it over mountain trails, will be necessary to transport the mica from the mine to Yachow, the nearest practical waterway. It is probable, therefore, that the output of the mine will be limited.Necessity for Careful Trimming and Grading of MicaA recent report to the Department of Trade and Commerce, Ottawa, Canada, by Acting Trade Commissioner C. G. Venus, London, England, contains information which is of vital interest to mica producers in the United States. It is pointed out that mica exports from Canada to England show a gradual decline dur¬ing recent years, the figures being as follows: 1913- 1,383 cwt: 1914 - 1,225 cwt: 1915 - 1,864 cwt: 1S16 - 879 cwt: 1917 444 cwt: 1918 - 480 cwt. Shipments from India to England, on the other hand, show a steady increase from 40,178 cwt. in 1913 to 66,401 cwt, in 1918."

Jan 1, 1920

Metals From Oil Shale. -A Geological Survey News Release in mid-January indicated that a surface sample analysis of oil shale in central Montana found a ton of shale to contain up to 13 pounds of zinc, 2 pounds of nickel, 1.8 pounds of molybdenum, 16 pounds of vanadium oxide, and nearly a quarter pound of selenium. It might be possible to recover some of these metals economically on a byproduct basis. The shale in central Montana was also estimated to contain 180 billion barrels of synthetic crude oil, which compares to estimated oil reserves in the Middle East of 360 billion barrels. Merchant Fleet Dwindles. -The National Maritime Council reports that although the U.S. is the world's largest trading power and that well over 90% of its foreign trade is conducted by shipping, the U.S. fleet is tenth in absolute numbers and less than 5% of its foreign trade is carried on U.S. ships. In 30 years, the U.S. fleet has dwindled from over 4,000 oceangoing vessels to about 600. U.S. ships carry less than 2% of imported iron ore, bauxite, and tungsten, and only 3% of oil imports.

Jan 1, 1981

By P. G. Clites

This study was conducted to determine the patterns of heat transfer to water-cooled copper crucibles during vacuum arc melting. Values of heat flux from the ingot to the crucible were determined during nonconsumable electrode vacuum arc melting of zirconium and during consumable electrode vacuum arc melting of titanium) zirconium) and steel. The results of these studies con-firm the existence of a high thermal resistance between the ingot and the crucible wall which results from the shrinkage of the ingot as the metal solidifies. Maximum heat flux occurs near the top of the ingot where maximum values of heat flux of 1.4 X 106 Btu/ft2 hr were observed during small-scale consumable electrode arc melting of zirconium and titanium. The maximum heat flux for consumable electrode arc melting of 8-inch-diameter ingots was 0.5 X 106 Btu/ft2 hr. The effects of electrode material) electrode diameter) arc current) and arc potential on heat flux from the ingot to the crucible were studied. Data were also obtained on crucible wall temperatures and on the effect of very narrow annular water jackets.

Jan 1, 1967

By Edward F. Divers

This Bureau of Mines report describes the results of a program to develop small, rugged scrubbers with high dust collection efficiency for use in under-ground coal mines. The Bureau's Pittsburgh (Pa.) Research Center has developed and assisted in the development of several types of improved scrubbers that are especially suitable for various underground mining applications. Research efforts concentrated on reducing the size, power, and water consumption of these scrubbers, while optimizing their dust collection efficiency. Fractional dust collection efficiency, air volumetric range, size, power, water consumption, and application guidelines for each type are described. Air pressure differentials ranged between 2-and 3D-inches water column (wc). The dust collection efficiency of six scrubbers--a venturi, two flooded-fibrous-bed, a venturi-impaction plate, a wetted-fan, and a rotating flooded-bed--were compared. The rotating flooded-fibrous-bed and the stationary flooded-fibrous-bed scrubbers showed the highest coal dust collection efficiency. Test results show that these scrubbers can generally achieve respirable size coal dust collection efficiencies in the high 90-pct range required to reduce both long-(8-hour) and short-term coal mine dust concentrations below Federal requirements.

Jan 1, 1979

By D. H. Baker

This report, one of a series prepared by the Federal Bureau of Mines on the technology of titanium, describes the development of an electrorefining cell from which cathode deposits up to 30 inches long can be produced. Data show individual deposits to be homogeneous, comparable from top to bottom, and not varied in quantity or quality of metal over the entire length of the deposit. Investigations concerned with various diameter cathodes showed that cathode current efficiencies were materially reduced with cathodes less than 2 inches in diameter. Deposits produced on 1/2-inch-diameter cathodes showed cathode current efficiencies of 19 percent and on 1-inch cathodes, just over 22 percent, whereas deposits produced on 2- and 4-inch-diameter cathodes showed about 70-percent current efficiencies. A series of 20 deposits on 4-inch-diameter cathodes was produced under simulated production operation. The average current efficiency, based upon a divalent ion, was 72 percent with 11 1/2 pounds of metal produced per cycle of operation - 98.8 percent of which had a Brinell hardness number (B.h.n.) of 80 or less.

Jan 1, 1959

Lower the respirable dust expo-sure of longwall mine workers by reducing the amount of air-borne respirable dust generated during coal extraction. Approach Increase the moisture content of the coal seam through water infusion before the coal is mined. How Water Infusion Works Increasing the moisture content in coal tends to prevent respirable dust from becoming air-borne during mining and transport. The moisture content of the coal seam can be increased by infusing water into the seam. Water under pressure is forced into the cracks (cleats) of the coal seam through sealed bore-holes. The effectiveness of water infusion is a function of the amount of water the coal seam accepts (its infusibility), which depends on the cleat density (cleat spacing) and cleat size (crack diameter). Thus the effect of water infusion on dust control depends mainly on coal seam characteristics. Water infusion techniques are generally used to restrict the flow of methane gas to the working face; however, the technique provides an alternative dust control method in mines with severe dust problems which limit production.

Jan 1, 1987

By Edward F. Divers

This Bureau of Mines report describes the results of a laboratory evaluation of a mechanical dust collector (scrubber) suitable for underground coal mine applications. The scrubber was developed by the Mining Research and Development Establishment (MRDE), Burton-On-Trent, England, and tested at the Federal Bureau of Mines Pittsburgh Mining and Safety Research Center (PMSRC) as part of a technical exchange program. The 2,000-to 8,000-cfm scrubber consists of an electrically driven vane-axial fan, water sprays, a 2-inch-thick, loosely knit stainless steel wire filter panel, and a water droplet eliminator. The dust-laden airstream travels axially through the water sprays, filter panel, fan, and eliminator. Slurry water drains into a sump where a belt-driven pump recycles it back to the sprays. Fractional breakdown tests showed a maximum dust collection efficiency of 96 pct of respirable-size (less than 7 µm) coal dust at 2,000 cfm. Efficiency decreased with increasing airflow; for example, to 91 pct at 6,000 cfm. Following these tests the original wire panel was replaced with a similar but smaller panel developed at PMSRC; a marked improvement in dust collection occurred at all flow rates tested.

Jan 1, 1979

By R. L. Handy

The goal of this research was to adapt the highly successful rock borehole shear test for use in deep, small-diameter boreholes. Operating somewhat on the principle of a rock bolt, the borehole shear test measures both the expansion pressure and pulling force to give discrete measures of rock shearing strength as a function of the applied normal pressure. A new instrument was designed and built to fit into a 2-3/8 inch diameter hole. Unfortunately the design became so complicated, the operation is nut reliable. This is attributed to constraints of the small hole, and added requirements of an in-hole anchor to push against, and a rotating shear plate cleaner for repeated tests down-hole. A clue to the d: vice complexity is its length, which is over 10 feet. Furthermore it employs concentric cylinders and one hydraulic cylinder bored into the piston of another, or it would be even longer. Meanwhile drilling technology has advanced to greatly reduce costs of drilling 5- or 6-inch diameter holes. The downhole tester therefore should be redesigned and simplified for use in a larger diameter drill hole.

Jan 1, 1982

By R. E. Peterson

The Bureau of Mines has undertaken beneficiation investigations on samples representing large tonnages of oxidized taconites in order to develop and evaluate applicable technologies for producing iron oxide concentrates from these materials. Information derived from the investigations can be used to expand the domestic iron raw-materials base and to establish the impact these taconite deposits may have on future national iron ore requirements. This report describes a process that includes reduction roasting, magnetic separation, and flotation, applied to a western Mesabi Range sample taken near Coleraine, Minn. The sample contained 36.8 pct iron and 46.0 pct silica, and represented 0.5 to 1 billion tons of crude material. An average of 962 lb/hr of oxidized taconite was roasted with 33 lb/hr of lignite in a 35-foot-long rotary kiln. Pulverized lignite and natural gas maintained the kiln operating temperature at 850° C. The roasted taconite was beneficiated by magnetic separation and cationic flotation in a 900-lb/hr pilot plant and yielded a product analyzing 68.1 pct iron and 4.6 pct silica, and containing 82.4 pct of the iron in the kiln feed.

Jan 1, 1981

By R. N. Roby

"INTRODUCTION A preliminary examination of the Green Monster and Benich copper prospects was made by engineers E. W. Newnan and George N. Bennett, of the Bureau of Mines, on December 13, 1943. In an unpublished report, it was stated that certain geologic features appeared to be similar to those associated with the copper deposits of the nearby Butte district. On these premises, a preliminary diamond-drilling program was recommended to explore 300 to 400 feet below the mineralized outcrops for the possible presence of a sulfide enrichment zone. In accordance with that recommendation, three holes were drilled. This report presents the data provided by that preliminary drilling exploration.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell D. Moon, chief, conducts preliminary exminations, perform the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyses samples and performs beneficiation tests.The field work on the Bull Run exploration project was supervised byE. W. Newman engineer in charge of the Helena field office. The chemical analyses and assays included in this report were performed under the direction of A. C. Rice, acting engineer in charge, Bureau of Minos Rare and Precious Metals Experiment Station at Reno, Nev. The diamond-drill cores were logged by geologists of the Federal Geological Survey."

Mar 1, 1947

By David C. Oyler, Winton J. Gale, Jinsheng Chen, Christopher Mark

A collaborative project between RAG Emerald Mine, NIOSH, and SCT Operations was conducted to investigate ground behaviour, reinforcement performance, and stress redistribution in a coal mine entry subjected to a severe horizontal stress concentration. Field measurements indicated that the stresses applied to the study site nearly doubled during longwall mining, resulting in roof deformations extending to a height of 4.8 m (16 ft) above the entry. This paper focuses on the computer simulation that was undertaken to provide more insight into the roof behaviour and rock bolt interaction during mining. The model’s input rock properties were derived from extensive laboratory testing, and the model itself simulated a broad range of failure mechanisms. The effects of different bolt patterns on roadway behaviour were evaluated. Comparison between the model results and the field measurements indicated that that the model effectively simulated the critical elements of the actual roadway’s behaviour. With the confidence gained, the model was used as a baseline for additional simulations that evaluated the expected performance of alternative roof support systems. The study will also provide a benchmark data set for future applications of numerical modelling to U.S. coal underground mining.

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

A - Contains the coordinate pair information for deriving the co¬efficients of the 3rd degree polynomial which approximates the loading station equation. C(N) - Coefficients for third degree approximating polynomial. I - General DO LOOP variable. K - Position in BRANCH of next character. L - Format specification in DEFINE FILE statement. X - Uniform displacement for random uniform number. Y - Load increment At. AO-A3 - Coefficients of approximating polynomial for loading station equation. GR - Grade direction, or grade resistance. IQ - Counts quadruples of distance grade speed and end of route for determining total distance. IT - Intersection counter in XXXDEF. Il - Station number trip is leaving. Jl - Station number for trip destination. J2-J8 - Motor assignments and functions for given trip. KK - Location of starting grade and distance in DISTGR KK - Position of decimal point in real number. KZ - DO LOOP variable for motor assignment check. LL - Location of ending grade and distance in DISTGR. Ll - Position in IECB of station satisfied. L3 - Next available position for IECB sort. MM - Flag for printing the failure of sanding to overcome slippage. NN - Trip destination in MOTSER RR - Rolling Resistance. XK - Station level or type.

Jan 1, 1974

By Thomas M. Barczak

Purchasing a new set of longwall shields requires a substantial investment. A poor shield design can lead to economic hardships, safety concerns for the mine workers, and closure of the mine. This paper addresses several key points that should be considered in the procurement process: (1) understanding your goals and the logic in selecting a higher capacity shield, (2) the importance of completing performance testing before production shield fabrication begins, (3) making sure performance testing is properly done, (4) measuring load(stress) development during performance testing, (5) testing a shield to failure, and (6) the value of buying extra shields. In addition, several challenges are proposed for consideration in future shield designs. These include (1) 100,000 life-cycle expectancy, (2) improved hydraulic diagnostic capability, (3) smart load control by optimizing setting pressures, (4) lubricated link joint design concepts, (5) composite material applications to reduce shield weight, (6) incorporating periodic weighting predictive algorithms into the data-processing software, (7) advanced component load measurement on two to three specially instrumented shields to detect loading in the structural components, and (8) constant set leg cylinder design.

Jan 10, 2000

By A. D. Garman

This paper presents one of a series of digests of foreign mining leg- islation and court decisions which is being repared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countrics. This interpretation of the laws of Panama has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers to who it is being referr ed through the courtesy of the Department of State.

Apr 1, 1930

Improve the safety and comfort of operators of large mining equipment. Approach Develop an improved driver restraint system that is easy to use, reliable, and cost-effective, while providing increased protection in the event of a collision or rollover. The Novel Restraint System There are several problems associated with conventional lap-belt type restraint systems. Among these are: restriction of movement, lack of comfort, and fear of entrapment. Standard seatbelts become dirty and oily from lying on the vehicle cab floor and can ruin a driver's clothes. Some haulage equipment may not even have seatbelts available to drivers since they are sometimes removed during maintenance activities or as a result of vandalism. Recognizing a need to address such problems by providing a more acceptable means of driver restraint, the Bureau of Mines designed and fabricated a novel vest-type restraint system. The vest is designed to be worn during a driver's 8-hour shift and would be issued much like safety glasses, hard hats and safety shoes, thus becoming part of the operator's individual protective equipment and assuring that each vehicle has a restraint system when in operation. The vest-

Jan 1, 1985