Search Documents

By Rudolf E. Greuer

The existing computer programs for the simulation of ventilation systems under normal ventilation conditions are reviewed and a suitable program for including the influence of mine fires is selected. New program parts are written for the consideration of methane productions in coal mines, heat and gas productions of mine fires, temperature and air composition changes in ventilation systems, and the ventilation forces resulting from the latter. Other program parts are provided for the detection of danger zones and reversed air currents and for the inclusion of recirculated air currents in the network analysis. Existing program and new program parts are combined. The resulting new program can be used for a multitude of assignments. It is designed for the practical ventilation engineer and should be applicable to all types of ventilation emergency plans, in particular mine fire plans. The organization of the program and its mathematical basis are described. A FORTRAN IV listing and several flow diagrams are included. Eight executed examples are discussed, input and output for these examples explained. Storage requirements and execution times are estimated.

Jan 1, 2011

By John R. Reynolds

This paper describes mining and milling methods of the American Smelting & Refining Co. at the Morning mine in the Mullan area of the Coeur d'Alene mining region in Idaho and is one of a series of Bureau of Mines reports dealing with methods and costs of mining throughout the United States. The Morning mine has been described previously in a Bureau of Mines report published in 1930,2/ and the milling methods and costs at the Morning concentrator were presented in a Bureau of Mines report published in 1932. 3/ These reports are supplemented by this publication, which presents data to show the effect of changing times and conditions on a typical medium-size mining operation during the latter part of its history, when costs were rising and production was from increasingly greater depths. The report contrasts two periods in the history of the mine-periods not too far separated in years but considerably different in economic conditions. During the first period (1939) costs of labor and materials were moderate, mining operations were just being transferred from the main shaft to deeper workings opened from the offset shaft, and the operation prospered. During the second period (12 years later) production costs had increased following the national trend in all industry, mining was from greater depths near the bottom of the ore body, and the operation was becoming unprofitable. Mining on the lower levels of the property ceased in 1953.

Jan 1, 1956

By Lee Ann Gardner

This U.S. Bureau of Mines publication presents a case study of the processes used in permitting the Nome Offshore Placer Project, a gold mining project offshore Nome, Alaska which operated from 1985 through 1990. The mining project, developed by Western Gold Exploration and Mining Company, Limited Partnership (WestGold), used the BIMA, which was at the time the largest bucketline mining vessel in the world, to dredge gold from the ocean floor. This case study reviews the permitting process from the regulators' and industry's perspectives, as well as characterizing the efficiencies and inefficiencies associated with this case. The Federal, State and local laws applicable to the Nome Offshore Placer Project are identified, agency jurisdiction and interagency relationships are explored, and the chronology of the permitting process is examined. The regulatory authorities for both environmental monitoring and post-mining monitoring are delineated. Significant milestones affecting the project and required regulatory submittals are also included. The case study of the Nome Offshore Placer Project is detailed with respect to agency involvement and coordination, approaches to permitting from both the regulators' and developer's perspective, environmental issues, and permit stipulations which were unique to the project. The advantages and disadvantages of these topics are discussed.

Jan 1, 1992

By Nicholas R. Dixon

This report summarizes all work performed under Phases I, II and III of U.S. Bureau of Mines Contract H0387006, "Development of a Prototype Retrofit Noise Control Treatment for Jumbo Drills." The noise and vibration levels of four jumbo drills were characterized and a survey of percussive rock drill usage is reported. A Gardner-Denver DH 123 drill was chosen as a demonstration drill, and extensive noise diagnostic studies were performed. Noise control treatments were designed, developed and evaluated in a reverberant drill test facility. The treatments consisted of an integral enclosure/muffler for the drifter, vibration isolation of the drifter from the enclosure and feed, and a drill steel sheath. A 19 dBA reduction in overall sound power level was achieved with no loss in drilling rate. The prototype retrofit treatments were field tested in an aboveground mine and in a production section of an underground zinc mine. Long-term durability and operator acceptance of the enclosure/muffler treatment were excellent. Preliminary evaluation of the drill steel sheath was encouraging, although additional testing is required.

Jan 1, 1982

By W. A. Calhoun

The purpose of this investigation was to develop economical mineral dressing processes for removing objectionable quantities of impurities, such as quartz and pyrite, from refractory clay deposits in east central Missouri. The presence of excessive quartz in these clays causes crazing. Pyrite causes bloating and unsightly dark blobs on the surface of fired refractory brick. The iron concentration in the proper state of oxidation may also act as nucleation centers for carbon crystal growth which can result in bursting of the refractory. Numerous deposits, representing a very large tonnage, have been examined and prospected by various refractories companies and found to contain impurities in objectionable quantities. Upgrading these clays would greatly extend our reserves of high-quality refractory clays. Wet-tabling and wet-cyclone concentration were found to be effective for removal of impurities from clays. Of the two methods, wet-cyclone concentra¬tion would be cheaper and more effective. Although wet-tabling improved the refractory properties of each clay, beneficiation by wet-cyclone produced clays of superior quality. Clay recoveries by wet-cycloning ranged from 56.1 to 81.8 percent of the weight of the crude samples, and the beneficiated clays contained from 71.9 to 94.4 percent of the total alumina. The pyrometric cone equivalent (PCE) was increased from 1 to 3 cones by wet-cycloning. The beneficiated clays also met the reheat shrinkage requirements on refiring to 1,400° C. Missouri is one of the major domestic sources of fare clay. In addition to deposits of high-grade refractory clays, there arc many deposits that contain small percentages of impurities, which render the clays unfit for the production of high-heat-duty firebrick. Development of methods to beneficiate these submarginal clays to usable materials would greatly increase commercial fire clay resources.

Jan 1, 1961

The U.S. Bureau of Mines has been concerned for many years with the general problems of underground coal mining and the particular problems due to the methane content of the coal. The Bureau and others have worked diligently to improve the health and safety conditions for underground coal miners. It has been recognized for many years that the methane in coal would have some value if it could he recovered and used, Also its removal before coal mining began or during the mining cycle itself would make mining safer and more economic due to a potential saving in ventilation costs. The work covered in this report was carried out to review methods of removing methane from active and inactive regions of operating coal mines and to determine how the methane could be concentrated and utilized economically.

Jan 1, 1975

This Bureau of Mines report reviews the information presented at the Sixth Mineral Waste Utilization Symposium cosponsored by the Bureau of Mines, U.S. Department of the Interior, and the IIT Research Institute. Environmental scientists and engineers from nine countries participated in the symposium, which was held May 2-3, 1978, at the Chicago campus of IIT Research Institute. The 56 papers presented on the reclamation and recycling of mining and mineral wastes, municipal solid waste, industrial wastes, and scrap metal are summarized herein.

Jan 1, 1980

By J. T. Popp

This Bureau of Mines study reviews the geological factors that affect methane in the Beckley coalbed in southern West Virginia, including overburden, coalbed structure, type of and changes in lithology above and below the Beckley coalbed, and presence of fractures in the coal and rock adjacent to the Beckley. Depending on the depth, the Beckley coalbed emits from 216 to 520 ft3 of methane per ton of coal mined, and the Bureau estimates that methane emission in a deep, extensively developed mine in this area may exceed 3,000 ft3 per day per ton of coal mined. Average face cleat and butt cleat trends in the Beckley coalbed measured underground are N 33° W and N 53° E, respectively. Close cleat spacing con¬tributes to the friable nature of the Beckley and provides easy movement for methane and water. Because rider coals, splits, and carbonaceous shales may contribute methane to mine emissions, predictions of methane emission based on gas content of the Beckley coalbed alone may be conservative. Beckley coalbed reserves in the study area are 234 million tons. The gas content of the Beckley coalbed averages 407 ft3/ton, and the coalbed gas reserves are 108 billion ft3.

Jan 1, 1976

By Gerald G. Johnson

The use of the Scanning Electron Microscope to characterize Coal Mine Dust has been possible because of two circumstances. First, the imaging process of the SEM allows multiple signals (secondary electrons, back scattered electrons, x-ray emission, etc.) to be viewed. Second, the use of a computer to analyze the signals and perform statistical tests on the results. The parameters described are size, shape, chemical composition, mass distributions, and particle thickness. Although the system is intended for particular systems, those of agglomerates (whether tile same or not) are handled by special aspects of the computer programs. The work on fibers is not completed at the time of this report. This work discusses the hardware (developed especially for this process) and software (both on an IBM 360/370 and a PDP 11/20). The latter system allows direct interaction between the operator of the SEM and computer for maximum information at the least time.

Jan 1, 1979

By G. C. Lammers

The object of this study was to determine the economic feasibility of hydraulically transporting Sandow (Tex.) lignite 100 miles and dewatering and thermally drying the transported lignite to a surface-dry condition. The most important factors involved in the feasibility of hydraulic transport, are the degradation incurred during transit, the length of the line, and the cost of alternative methods of shipment. In pipeline tests in which roughly 75 miles of hydraulic transport was simulated the percentage of minus-325-mesh solids increased from about 1 to 41 percent for both lignite and bituminous coal; in the micron sizes the coal fared considerably better than the lignite. Such degradation, even though it enhances flow through the pipe-line, severely aggravates the dewatering problem on lignite. Cost studies indicated that continuous vacuum filters offer the most economical means of dewatering minus-1/8-inch material. Surface moisture, if high, must be removed by relatively expensive thermal drying.

Jan 1, 1958

By Verne E. Hooker

Near-surface temperature measurements in two granite quarries show that diurnal temperature variations are significant to a depth of 1 or 2 feet, and annual temperature variations are significant to a depth of at least 25 feet. As a result, ground stress anomalies due to temperature exist near the surface, and their magnitude depends upon the time of day and the time of year. Rock stress and corresponding temperature measurements were made in one granite quarry over a rock temperature range of 33° to 81° F. Measured rock temperatures show good agreement with values predicted from one-dimensional heat flow theory. Calculated and measured stress-temperature coefficients for the two granites in this study are given. Thermally induced stress variations in near-surface rocks tested were as large as 1,690 psi from combined daily and seasonal temperature changes.

Jan 1, 1971

By Galen G. Waddell

This report describes a method of measuring and analyzing the initial deformation which occurs in the medium surrounding a mine accessway as the opening is created. Discussed are (1) the hypothesis upon which the research is based; (2) the in situ rock-deformation measuring equipment developed; (3) the field tests, consisting of measuring the deformation of the medium around two 4-foot-diameter raise bores as the boring progressed; and (4) a finite-element technique to correlate theoretical with experimental results, using elastic theory. Described also are the raise-bore operation and performance. The instrumentation developed proved to have the sensitivity and resolution necessary to measure rock deformation around a full-scale raise bore during excavation. Tests show the relationships of rock deformation to progress of the raise boring and to time. The initial deformation of the opening appeared to be elastic. Using the deformation records and an estimated field stress, the modulus of elasticity was determined for the rock mass. In addition, the importance of this type of measurement in assessing support-problem areas is discussed.

Jan 1, 1971

By W. D. Kaiser

Recent legislation and expected future legislation is aimed at reducing the dust levels developed in underground coal mines. Several techniques for reducing dust levels are being evaluated. One of these is the modification of cutting parameters such as feed rates, cutting speeds, and pick configurations in order to reduce the amount of dust generated. In order to evaluate the feasibility of modifying cutting parameters to reduce dust, the Bureau of Mines commissioned Battelle to construct a small scale mining machine which could be used for evaluating the effects of those changes in cutting parameters. Specific features of this machine were that it should be highly instrumented to measure various cutting parameters, should have a wide range of feed and speed controls, and it should be possible to vary the pick configurations and geometries on the machine. In addition, it was desired that this machine should have cutting capabilities which greatly exceed present coal mining practice and also that the unit should be small enough and portable enough that it could be taken into and out of operating coal mines with a minimum of interference with the normal coal mine operations. The first step in constructing a machine to meet these requirements was to determine the cutting forces and approximate sizes of components which would be required to cut at the speeds and feeds specified by the Bureau of Mines. Initial calculations using; published data on cutting forces indicated that cutting forces in the neighborhood of 5,000 lbs and power levels of approximately 30 horsepower would be adequate for the application. However, further data developed during the course of the project indicated that when low efficiency picks are used, cutting forces and powers can be two to three times as high as these initially estimated values. After several design iterations, a design was chosen in which the cutting head was driven by four hydraulic motors which were part of a hydrostatic transmission which, in turn,

Jan 1, 1973

By Roger J. Morrell

Bureau of Mines laboratory experiments with reduced scale cutter and cutter forces were performed to (1) define the fundamental relationships governing disk cutter performance and (2) to develop a method of predicting disk cutter performance in soft, medium, and hard rocks. The rock cutting experiments were performed in four igneous and metamorphic rocks that ranged in compressive strength from 38,000 to 67,000 psi. A special testing machine called a linear cutter apparatus (LCA) was used to load and traverse a free rolling disk cutter across a smooth rock surface. Each pass of the disk produced a single crater, and runs were spaced to avoid breakage between craters. During each run the normal and tangential cutter forces were measured and recorded. The soft and medium rock data were obtained from previous Bureau experiments with disk cutters. Crater depth, tangential cutter force, crater volume, specific energy versus normal cutter force, and crater width versus depth are defined within this study. With the use of standard physical properties, performance prediction equations were developed using stepwise linear regression analysis techniques. A method of using these prediction equations to calculate the boring rate, the cutter spacing, and the torque and energy requirements of a full-scale boring machine was also developed.

Jan 1, 1974

By G. W. Jones

One of the major activities of the Bureau of Mines is the promotion of safety in mining and other industries, In this connection, the Bureau determines the explosion hazards' of combustible gases, vapors, and solids and investigates means of controlling and preventing explosions. Many dangers are likely to confront men who must enter a building immediately after it has been damaged. Rescue workers must watch constantly for common gases and vapors that may be present in dangerous concentrations in and about demolished, buildings. Fuel gas is the most common source of danger, although refrigerants, gases from furnaces, flues, fires, sewers, and industrial processes, and gas from bomb, explosions in confined places also constitute definite hazards. To rescuers and trapped casualties, these gases offer the hazards of (1) explosion, (2) toxic effects, including asphyxiation and death, and (3) displacement of air so that the oxygen content of the atmosphere is reduced to or below the danger level.

Jan 1, 1944

By Robert C. Hickman, Xavier B. Starnes

"The general location of the Kentucky, Fluorspar District and the Moore Hill fault area are shown in figure 1. An engineer3/ the Bureau of Mines visited the district in July 1942 and reported on the Moore Hill fault system. Subsequently the Bureau explored the Summers, Pepperbox, McCune, Eagle-Watson, Henry Watson, Davenport, Felix Tyner, and Eagle-Wring prop¬erties by core drilling. These properties and the principal faults are shown on figures 2 and 3.Collaboration of the Federal Geological Survey4/ was of great benefit, particularly in mapping the properties, determining the stratigraphy, and furnishing information on that and other geologic factors.Fluorite was noted as early as 1818 near Shawneetown in southern Illinois.5/ In 1835 an attempt was made to work deposit in Crittenden County, Kentucky, but interest centered chiefly upon the galena found with the fluorite. The first shipments of fluorspar from Kentucky wore made in 1373 from the Yandell mine of Crittendon County.6/ It is not known when the first work on the Moore Hill fault was done, but it seems probable that the Cullen-Eagle and Nancy Hanks were being ,worked in 1900. Gravel spar was found on the surface at the Two Brothers mine in 1904,7/ and the main shaft was started in 1914; work also began at .the Davenport in 1914, and in 1917 the Eagle-Watson was in production. A shaft was gunk on the Pepperbox in 1918, and in 1922 fluorspar was found and work was started on the Summers property. In 1924 work began at the McCune, Felix Tyner, Eagle-Wring, and probably the Hicks properties.No Good approximate record of production from each property on the Moore Hill fault system is obtainable, but an estimate based upon all data available is as follows:"

Sep 1, 1946

By Robert M. Doerr

The research objective was to determine the effect of aluminum alloy additions on the oxidation behavior of cobalt-nickel alloys. Thirty high-purity alloys were reacted with 02 at 0.5 atm at 1,351°, 1,389°, and 1,429° K in a volumetric apparatus for about 300 min. The alloy compositions consisted of Co-Ni master alloys (0, 22, 50, 70, 91, and 100 wt pct Ni) with aluminum additions of about 0, 1, 2, 4, and 8 wt pet. Large early deviations from, or changes in, the parabolic rate constant were encountered, but in most cases, the reaction rate declined approximately in accordance with the parabolic rate law. A sharp peak in the parabolic oxidation rate constant was observed for specimens containing a to 22 percent nickel and 1 to 2 percent aluminum at 1,351° K, and the rate constants for these compositions were lower at the higher temperatures. Specimens containing 8 percent aluminum reacted far more slowly than did any of the others.

Jan 1, 1971

By Thomas Jenning, C. M. Keithly

"INTRODUCTION This report is one of a series. 4. 5. 6/ concerned with presenting historical development, and operating data on secondary-recovery projects in various States to stimulate interest in sound secondary-recovery programs. Preceding reports in this series have dealt exclusively with descriptions of and results obtained by water flooding in three states, but no recent publication of comparable purpose describes gas-injection 7/ practices. The authors intend to present material relevant to the development and operation of gas-injection projects in Illinois, with particular emphasis on those producing from oil-bearing horizons that had been depleted to a point near the economic limit of operation by past oil-recovery methods.Most operators realize that the energy expended on the movement of fluids through gas-expansion- or gas-cap-type oil reservoirs to producing wells must be supplemented to attain maximum recovery of the oil present. Under favorable conditions, many operators choose to maintain oil-propulsive forces at or near their original magnitude by injecting extraneous fluids into a reservoir or recycling produced fluids early in the life of a field. More common, and less desirable, is the practice of replenishing these forces after primary producing methods become unprofitable. The lattes practice has been adopted in many stripper fields in Illinois and most of the oil-producing States during the last 40 years, but other old oil fields, and oil properties within those fields which were partly exploited by secondary--recovery methods, also may offer favorable opportunity for further development. To encourage and, aid operators in the development of gas-injection projects in the old oil fields of the United States, four projects have been described in detail in this report."

Nov 1, 1944

By V. F. Parry, W. S. Landers, John B. Goodman

"INTRODUCTION The object of this investigation was to demonstrate a satisfactory method of storing slack subbituminous coal in open pits in a manner,that would minimize the cause of the physical deterioration and would have a practical application.The storage of coal by industrial plants is to their advantage, since an adequate operating supplying of fuel is available at all times as insurance against transportation delays, shortages, and strikes. Furthermore, it is possible to participate in low seasonal freight rates and mine costs by permitting the railroads to utilize idle equipment and by taking advantage of the off-peak production at the mines. For a number of years, one of the larger beet-sugar companies operating in the Rocky Mountain region has taken advantage of the lower prices and seasonal production of subbituminous slack coal during the summer months and purchased a large proportion of its requirements for the annual winter campaign. This company, operating sugar-refining plants in the 1943 campaign, used 256,613 tons of subbituminous coal. Of this quantity, 166,636 tons was purchased during the off-peak season and stored for use during the winter. It is the practice of this concern to place coal purchased through the months of January to October in underwater storage for use in the beet-sugar campaign, which lasts from October to as late as, January. The beet-sugar refining ""campaign"" period starts immediately after the beginning of the beet harvest and lasts 60 to 70 days."

Aug 1, 1946

By F. S. Karn

Conditions necessary to obtain optimum yield of useful products when coal is rapidly heated to extreme temperatures by laser irradiation were determined by the Bureau of Mines. Product distribution and yield were investigated as functions of several variables. Low-rank coals with high-volatile matter gave highest total gas yields. Medium-rank coals gave the highest yields of H2 and CA and low-rank coals gave highest yields of CO and C02. Macerals gave gases of approximately the same composition, but the total gas yield increased in the order fusinite, micrinite, vitrinite, and exinite. Total gas and C2H2 yields varied inversely with particle size. The addition of nominally inert gases such as Ar, He, N2 increased yields of H2, C2H2, and total gas. Metals such as nickel and platinum had little influence on the rate of coal decomposition. Total gas yield increased with total energy of irradiation, and the ratio of C2H2-CH4 increased with concentration of energy. A study was also made of the irradiation temperature, and a material balance was calculated.

Jan 1, 1970