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By Sandip K. Mukherjee

This report presents the results of the economic analysis of several applicable alternatives to increase airflow in four underground coal mines. Pressure-quantity surveys were conducted underground and measurements were also made at the main mine fan(s). The existing ventilation networks were modeled using the modified Penn State ventilation simulator. The applicable alternatives were simulated. Performance data obtained from these simulation runs were utilized to conduct the cost-effectiveness analysis. The costs for each of the alternatives included capital, operating and operating costs. These costs were expressed as annual ventilation costs per active section in terms of dollars per cfm taking into account the economic life associated with each of the alternatives. The benefits were expressed as increased airflow quantity in the critical sections. A section of this report also deals with comparison of simulator predicted air quantity values against air quantity values measured under-ground. This volume constitutes Volume II of the report and contains the outputs of the computer simulation runs.

Jan 1, 1983

By R. R. Joseph, K. A. Gschneidner

The solid solubility of magnesium in the close-packed modifications of lanthanum, cerium, praseodymium, neodymium, gadolinium, dysprosium, and lutetium was determined from approximately 250°C to the eutectoid temperature by the X-ray parametric technique. The maximum solubility at the eutectoid temperature was found to be 9.4 at. pet in La, 8.2 in Ce, 9.2 in Pr, 8.2 in Nd, 14.1 in Gd, 13.5 in Dy, and 11.5 in Lu. The solubility when compared at a homologous temperature was found to increase in a smooth manner with decreasing size factor from lanthanum to lutetium. It was found that the apparent atomic radius of magnesium when dissolved in the lanthanide solvent was constant and could be accounted for by consideration of several models dealing with departures from Vegard's law. The eutectoid temperatures for the lanthanide-rich La-Mg, Ce-Mg, and Nd-Mg systems were found to be 544", 505°, and 551°c, respectively. A study of the solid solubility of magnesium in the lanthanide metals was initiated because the valency and electron egativity difference are essentially constant and favorable for solid-solution formation, and thus one could examine the effect of size on terminal solid solutions. The size factors based on metal radii range from 14.6 pet for lanthanum to 7.5 pet for lutetium. Since the electronegativity difference is small, 0.06 unit or less, application of the Hume-~othery' and Darken and Gurry2 criteria for solid-solution formation indicates that the solubility of magnesium would be expected to be small for lanthanum (between 5 and 10 at. pet) and to increase as we proceed along the lanthanide series. A search of the literature revealed no data on the solubility of magnesium in the lanthanide metals except for the solubility of magnesium in cerium at 450oCA typical phase diagram for the lanthanide-rich end of the lanthanide-magnesium phase diagram is shown in Fig. 1. EXPERIMENTAL PROCEDURES Preparation of Alloys. The lanthanide metals used in the preparation of alloys for this investigation were prepared from the corresponding fluoride by metallothermic reduction techniques previously described by Daane.4 The chemical analyses of the metals used are listed in Table I.

Jan 1, 1965

By Charles Sabine

The U.S. Bureau of Mines studied mines and prospects in the Bristol/Granite Mountains Wilderness Study Area (WSA) in 1982. The 45,000 acre WSA, located in the eastern Mojave Desert of California, is underlain by Mesozoic plutonic rocks with scattered roof pendants of Paleozoic (?) metasedimentary rocks. Two mines and six prospects are identified; one mine, the Silver Lode Mine, and a prospect of unknown name are adjacent to the area. The Silver Lode Mine has occurrences of silver, lead and zinc. Within the study area, the Comanche Mine has occurrences of iron and copper and the Iron Victory Prospect has an occurrence of iron. None are large enough to constitute a resource. Occurrences of magnesian marble at the Comanche Mine, Iron Victory Prospect, and elsewhere in the area contain too much MgO for commercial use other than agricultural soil supplements or crushed stone. Transportation costs to markets would exceed the value of the rock. At the Comanche Mine, situated in a roof pendant of marble, about 10 tons remain of a 110-ton pod of magnetite which contained 42.5% iron, and less than 50 tons remain of a mineralized fault breccia which averaged 2.5% copper and 0.3 oz/ton silver. Magnesian marble contained 41 to 45% CaO and 14 to 16% MgO. Primary and secondary silver, lead, zinc, and copper minerals are disseminated along altered joints and in quartz veins in quartz monzonite at the Silver Lode Mine, adjacent to the WSA. Analytical data are sporadic; samples contained as much as 0.12 oz/ton gold, 1.8 oz/ton Silver, 1.1% lead, 3.8% zinc, and 0.3% copper. Mineralized zones in the workings are not resources, but they might indicate possible silver-lead-zinc resources at depth. At the Iron Victory Prospect, lenses of magnetite and hematite with some chalcopyrite occur in a skarn lone in a marble roof pendant. About 110,000 tons of iron-rich rock, averaging 47.2% iron, are present; the largest lens contains about 30,000 tons. About 150,000 tons of magnesian marble, averaging 41.0% CaO and 11.7% MgO, are also present. Deposits of stone, and sand and gravel in the WSA are too distant from markets to be resources. Occurrences of energy minerals were not identified.

Jan 1, 1984

By R. A. McIvor, R. Levac

"The Stobie No. 7 shaft, 14 ft diameter, double- drum skip hoist, was installed at the INCO Limited Frood Stobie Complex in 1942. Figure 1 shows the hoist layout. The hoist was originally equipped with babbitted journal bearings on the main drum shaft and pinion gears. In 1990, the hoist was modernized with a new braking system, two new 2000 hp D.C. drive motors, a thyristor armature supply and a PLC control system. The new drive motors were connected to the drive pinion gears with a gear type flexible coupling. The pinion gear journal bearings were refitted during the refit in 1990 as the existing babbitted bearings showed signs of wear. The pinion gear journal bearings had always run warm and had external cooling applied during the warm summer months. Figure 2 shows the journal bearings on the pinion shaft. The skip hoist main bull gear and two pinion gears were replaced in 1997 because of cracked bull gear spokes. New drive couplings were installed on the pinion gears and the pinion journal bearings were modified to allow some self-aligning properties to try to reduce the heating and wear on the babbitt. The modifications did not significantly reduce the heating problems and a decision was made in the spring of 1998 to convert the bearings to self-aligning, anti-friction-type bearings.The traditional roller bearings used on double helical pinion drive gears in hoist applications has always been double-row spherical roller bearings due to their high load-carrying capacity and misalignment allowances.Unlike single helical gears, double helical arrangements do not exert axial thrust on the pinion gear bearings, therefore, both bearings in the pillow blocks must float easily with any pinion displacement. Drum misalignment, thrust bearing end play and a multitude of other influences causes continuous axial displacement of the pinions when in operation. This constant displacement or “hunting” of the pinion gear to maintain its centre on bull gear often exceeds the axial clearance limits of spherical roller bearings thus resulting in a continuous sliding motion of the bearing outer rings against the housing seats. With time, the housing fit eventually wears, creating an out-of-round condition for bearing housing (maximum allowable cylindricity tolerance is IT4/2). When this happens, the pillow block housings must be replaced or re-machined to specification. Premature bearing wear and overheating will occur if a housing out-of-round condition is encountered."

Jan 1, 2001

By J. W. Klokow, K. L. Riemer, R. I. L. Ferreira

As a result of the increased depth of mining in the South African gold mining industry mining induced seismicity is a severe problem. One of the strategies within the industry to contain the problem is to incorporate a system of regularly spaced stabilising pillars into mine layouts. At the Driefontein Gold Mine a system of closely spaced dip pillars is used to contain seismic energy emissions. Comparisons of seismic data for several mining clusters initially indicated a possible measure of success in the containment and occurrence of larger events. A detailed analysis of data over a 5-year period since the start of mining however, has revealed a delayed seismic response to the increasing strike spans. Significant changes marked by an increase in certain seismic variables have been observed at mining spans of between 100 to 120 meters and could be of significance to pillar spacing in the design of deep level mining layouts. La sismicité occasionnée par l’exploitation minière est un problème grave dans les mines profondes de l’industrie minière aurifère en Afrique du Sud. Une des stratégies utilisées dans l’industrie a été de maîtriser le problème en incorporant un système de piliers de stabilisation régulièrement espacés dans la disposition des mines. A la Driefontein Gold Mine, un système de piliers de pendage proches les uns des autres est utilisé pour contenir les émissions d’énergie sismique. Au début, des comparaisons de donnés sismiques pour plusieurs groupes d’extraction ont indiqué un succès possible dans la limitation et l’occurrence d’évènements sismiques. Cependant, une analyse détaillée des données sur une période de 5 années a révélé un délai entre la progression de l’extraction et une réponse sismique accrue. Des changements considérables dans les variables sismiques ont été observés dans des intervalles d’extraction entre 100 et 120 mètres, ce qui pourrait être significatif pour l’espacement des piliers dans la conception de la disposition des mines de fond. Resultierend aus den zunehmenden Tiefen des Bergbaus in der südafrikanischer Goldbergbauindustrie stellt sich die vom Bergbau hervorgerufene Seismizität als bedrohliches Problem dar. Es war eine der Strategien innerhalb der Industrie, das Problem dadurch einzudämmen, daß regelmäßig plazierte Stabilisierungspfeiler in den Bergbaulayouts inkorporiert wurden. In der Driefontein Gold Mine wird ein System von knapp aneinandergesetzten im Abfallbereich befindliche Pfeiler benutzt, um seismische Energieemissionen einzudämmen. Vergleiche der seismischen Daten für mehrere Bergbaugruppen zeigten anfangs ein mögliches Maß von Erfolg in der Eindämmung und im Auftreten von größeren Fällen an. Eine ausführliche Analyse von Daten über einen 5jährigen Zeitraum hat jedoch ergeben, daß eine Verzögerung zwischen der Progression des Bergbaus und einer erhöhten seismischen Reaktion besteht. Bedeutende Änderungen in den seismischen Variablen wurden an Bergbauspannen von 100 bis 120 Metern beobachtet und könnten für Abstandsbemessung von Pfeilern im Design des Tiefbergbaulayouts von Bedeutung sein.

Jan 1, 2003

By H. E. Powell

A laboratory investigation was conducted by the Bureau of Mines to study the magnetic characteristics and to measure the magnetic susceptibility of the mineral siderite. All susceptibility measurements were made by the method of Gouy on powdered samples and at room temperature. Specific susceptibilities of samples from 15 different locations, domestic and foreign, were determined. Values ranged from 66 to 103 (10-6) cgs electromagnetic units. The relation of susceptibility to mineral composition is discussed in this report. The specific susceptibilities of 76 minerals are tabulated in an appendix.

Jan 1, 1963

By Fred E. Fiedler

A demonstration project investigated the feasibility and effectiveness of two management interventions, Management Training and Organization Development, for improving productivity and safety in metal/non-metal mines. The management training intervention was conducted at Texasgulf Company's trona mine, using three nearby trona mines as controls. The Organization Development intervention took place in Hecla Mining Company's Lucky Friday mine, using the highly similar Star Mine as control. The two management interventions seemed about equally effective in reducing accidents and injuries, as well as MSHA citations, and the management intervention at the Texasgulf mine also appeared to have led to substantial improvement in mine productivity.

Jan 1, 1983

By LaMar G. Evans

The rapid determination of uranium in ores by radiometric means was investigated by the Bureau of Mines. Among the various procedures and schemes tested, two showed most promise. They were the ratio scheme developed in the Bureau's Tucson, Ariz., laboratory and the equilibrium method developed by the Canadian Department of Mines and Technical Surveys. The ratio method is a simple, empirical procedure for classifying the state of equilibrium in ores by measuring their radioactivity by means of a Geiger-Muller counter under three different conditions, using filters. The principal merit of the method is in providing a clue as to the reliability of equivalent uranium determinations.

Jan 1, 1958

By M. van Schoor

Coal remains South Africa?s most abundant and cheapest source of energy, and there is an ever-increasing necessity for optimal and safe extraction of the remaining reserves. Increasing focus on cost-effective mining and zero harm to the environment and miners has resulted in a shift in attitude towards the application of geophysics in local coal mining and exploration. Furthermore, technological advances have contributed to geophysics being embraced more readily by the coal mining industry, compared to a decade or two ago. Predictably, the growing interest in geophysical technologies has also created a need for education and training in the basic principles and application of geophysical methods, as local coal mining companies generally do not have in-house geophysicists. Consequently, the Coaltech Research Organisation?s Geology and Geophysics working group forum compiled a textbook aimed at addressing this need: to produce a guide for applying geophysics to coal mining problems in South Africa. The target audience for such a book would be coal geologists, mine surveyors, mine planners, and other mining staff with limited or no geophysics background. This paper provides a very brief overview of the book by summarizing key sections and selected examples. In doing so, the value of geophysics to solving a range of coal mining and exploration problems is highlighted.

Jan 1, 2014

This study was conducted to determine the feasibility of using large tractor dozers in land reclamation of strip-mined areas. The procedures used are patterned after engineering models developed for evaluation of military ground vehicles in cross-country operations. Tractor dozer manufacturers furnished information on capabilities of existing equipment and ideas on the practicability of using dozers larger than those currently available Generally, they believe that current dozers in the 500? to 700-horsepower range are about as large as can be built and remain economically feasible. However, one manufacturer has a wheeled dozer rated at 1200 horsepower, and another is testing a tracked dozer of about the same horse-power.

Jan 1, 1975

By Heiner J. Sander

Stanford University operates the National Research Facility which is located at the Stanford Linear Accelerator Center (SLAC) in Menlo Park, California. In order to improve and allow for enhanced experiments, the current facilities required expansion. A1500 foot long tunnel (20 ft wide by 21 ft high) and a 220 foot long underground cavern (49 ft wide by 32 ft high) were excavated through the Ladera Sandstone formation which is an intermediate geo-material with week rock properties. The overburden between surface and crown of the structures varies from 10 to 80 feet. The underground structures were excavated according to the principles of the NATM (New Austrian Tunnel Method). This paper addresses the challenges that were encountered during the construction phase of the project and how construction issues were resolved mutually by the owner, engineer and contractor. The implementation of geotechnical instrumentation, recorded data and interpretations, soil conditions and behavior encountered during construction are also presented.

Jan 1, 2008

By Calvin K. Lee

This Bureau of Mines report describes a simple fire-retardant treatment for wood. The treatment involves preheating the wood surface at high heat flux (~0.6 cal/cm2 sec) to form an in situ surface char layer (~3 mm thick) on the wood. Laboratory-scale fire tests show that the precharring technique improves the fire-resistance of virgin wood by decreasing and delaying generation of volatile gases through thermal insulation effect of the surface prechar layer.

Jan 1, 1978

By T. J. McKeon

Partition curves are used to evaluate the separation performance of gravity-based concentrators. The partition curve is used to identify the nominal density cutpoint and relative sharpness of the separation. In addition, the graphical representation makes it possible to quickly identify the root cause of misplacement based on the characteristic shape of the partition curve. Partition curves have been traditionally constructed using data obtained from float-sink tests using heavy organic liquids. These toxic liquids are environmentally unfriendly and have been banned in several countries. Another method of establishing the partition curve is to introduce density tracers into the feed and plot the distribution to the lights and heavies. For heavy mineral separations, this approach is generally impractical due to the fine particle size. In addition, the partition data obtained using these existing techniques do not account for secondary factors such as particle shape that may influence the separation. In light of these problems, a methodology was developed for constructing partition curves using experimental data obtained from microscopic grain-counts. This technique, which essentially uses the different mineral species as density tracers, provides a powerful tool for evaluating heavy mineral separations. A case study is provided to demonstrate how this analytical approach can be used to assess and improve the separaton performance in an industrial upgrade plant.

Jan 1, 2005

By Arnis Mangolds

A study of the technical and economic feasibility of using a unique undercut and fill system developed by USBM engineers to mine steeply pitching coal is discussed. A brief resource assessment has indicated that significant reserves exist in most coal regions to justify the development of a safe and economical method of extracting steeply pitching coal. The undercut and fill system combines hydraulic coal cutting with unassisted gravity fluming of the coal slurry. Mining occurs across strike and the extended entry is backfilled to provide uniform strata control and an impermeable water and air barrier. Subsequent mining occurs beneath the previously filled stope such that the roof consists of a solid, controlled back. In addition to providing positive roof and hanging-wall support, the backfill system eliminates subsidence potential, post-mining drainage, and the danger of spontaneous combustion from naturally drafting air currents. A unique through-flowing ventilation system permits passage of return air through the production face via ducting located at the backfill-coal junction. This provides a constant supply of fresh air at the face, eliminates the need for brattice cloths, and provides an additional escapeway for the miners. The preliminary estimates indicate a production rate in the neighborhood of 31.9 tons/ manshift. Capital costs are approximately $3.17/raw ton over a 20-year life with an initial investment per annual ton of $48.29. Total cash-costs for labor, supplies, power and benefits range in the vicinity of $19.59 for a 704,460 ton/year mine, or a total cost of $22.76/ton. These costs do not include federal and local taxes or post-of-money; however, the cost of coal is well within the area selling price.

Jan 1, 1981

By Narasimhan K. S, Sastri S. R

A typical high silica low grade magnesite from the Salem area of Southern India, was used in studies to develop a suitable flotation system involving commercially inexpensive sodium oleate as the collector together with other reagents which can give a product of the required grade with an acceptable recovery. It was found that the presence of metallic ions such as Cu+, Fe+++ or Ca++ introduced by the addition of their salts, or by their formation with the addition of hydrochloric acid to react with magnesium and calcium carbonate in the me, can act as effective depressants for silica. The addition of 'hydrochloric acid' was found to give best results.

Jan 1, 1980

By Robert D. Perry

This report describes methods of reclaiming abandoned or inactive tailings ponds and dams. The investigated sites were selected tailings deposits adjacent to metal mines in the southwestern United States and the Pacific Northwest. The basic data developed for each site consisted of the following: a review of existing literature: a site visit that included sampling of the tailings and surrounding materials; laboratory and engineering studies; and development of reclamation plans. Laboratory tests determined the gold and silver content of each tailings deposit and the chemistry of the tailings and surrounding materials. Reclamation plans that include approximate costs were developed for five tailings deposit sites. These ranged in size from 52,000 to 103,000,000 tons. Our conclusions on the remining potential of each site are based on the tailings assay and other technical data. This study concludes that remining as a reclamation tool is feasible at certain sites. Included in this report is a remining program as part of the overall reclamation plan for two sites. Our preliminary results indicate that remining as a reclamation tool is feasible for only one of them.

Jan 1, 1981

Executive A R LEDOUX, Chairman ARTHUR S DWIGHT CHARLES F RAND E P MATHEWSON J V W REYNDERS Membership E DEGOLYER, Chairman W Y WESTERVELT, Vice-chairman WILLIAM H BASSETT H G MOULTON C MINOT WELD Finance WALTER H ALDRIDGE, Chairman GEORGE D BARRON GALEN H CLEVENGER Library GEORGE C STONE,' Chairman JOHN H JANEWAY ALEXANDER C HUMPHREYS, ROBERT LINTON FREDERICK F SHARPLESS

Jan 1, 1923

By W. H. Somerton

Many oil-producing formations contain significant amounts of clay. Because of the large surface area and reactivity of such surfaces, the response of the formations to various recovery processes may be dominated by the reactions of fine-grained minerals, including clay minerals, in the formations. Thus, the success or failure of enhanced oil recovery (EOR) methods may be controlled to a large extent by the amount and nature of these minerals in the formations to which the methods are being applied. One of the deterrents to the successful application of chemical EOR methods is the loss of chemicals injected into the formation, to non-oil recovery processes. These chemical loss processes include adsorption onto mineral surfaces, chemical reactions with rock and fluids in the formations, possibly leading to precipitation and plugging of the formation, and trapping of chemicals in parts of the rock structure so that they become unavailable for displacing oil. Chemicals that may be injected include surfactants, polymers and caustic solutions which react with organic acids in the crude oil to produce surfactants in-situ. These losses are most pronounced in fine-grained reservoir rocks containing substantial amounts of clays.

Jan 1, 1984

By J. S. Dunning

One Federal Bureau of Mines research goal, to minimize requirements for domestically scarce mineral commodities through conservation and substitution, can be accomplished by utilizing more abundant elements such as iron, molybdenum, and titanium. An example of this research is the study of precipitation-hardening, iron-base alloys containing molybdenum and titanium, as substitutes for the high-tonnage stainless steels that are high in imported nickel and chromium. The precipitation hardened iron-base alloys are strengthened by a dispersion of the ternary Laves phase, Fe2 (Mo, Ti). Aluminum and chromium additions changed the solid solubility limits of molybdenum and titanium in a-iron and affected the composition of precipitating phases. A baseline composition of Fe-7Mo-2Ti was selected to study the effects of aluminum and chromium additions on the precipitation-hardening mechanism and microstructure and was also used in studies of mechanical properties and oxidation resistance. The study yielded workable, precipitation-hardening alloys, with elevated temperature strengths equivalent to or superior to types 304 and 316 stainless steels. Chromium and aluminum additions in combination were more effective in providing oxidation resistance than either addition was alone.

Jan 1, 1980

By Parviz F. Rad

The Bureau of Mines used a linear cutting apparatus equipped with a 7-inch disk cutter to cut grooves in marble, limestone, granite, and quartzite under a normal force of 7,000 lb. The size distribution of the muck for various grooves was determined through sieve analysis. A statistical search showed that Weibull distribution describes the size distribution better than other available functions. Results indicate that fineness modulus, chip population, and dimension of the largest chip can be used as indicators of cutting efficiency. The results correlate with those obtained from the boring machines and other lab experiments. Application of the principles established through this work to the operation of boring machines is explained

Jan 1, 1974