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By John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By Lawrence H. Roth

Past failures of coal refuse embankments have resulted in more intensified efforts in inspections of coal refuse sites. Inspections, however, are mainly qualitative and time consuming. In August 1975 CH2M HILL was awarded a contract to identify, develop, and test a rapid system for monitoring coal refuse embankments to aid in inspections. The rapid monitoring system developed uses convergent and vertical photography from conventional fixed-wing aircraft. The system was tested on an active landslide and on two coal refuse facilities using both black and white and color infrared film. Field tests showed the system was capable of accurate measurement while providing qualitative data through photointerpretation. The accuracy of the system allows it to be used to monitor coal refuse embankments, tailings dams, major earth dams, and natural slopes. Bibliographies of literature reviews in the area of past coal refuse embankment failures, monitoring instruments and methods, and photogrammetry are included.

Jan 1, 1977

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the ninth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township map. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By Clark P. Mangelsdorf

The report consists of two parts. In Part I is a state-of the-act study of roof truss technology as of January 1979. Included are a history of the truss concept, a review of analysis techniques, a record of hardware available and equipment used in its installation and numerous examples of user experience. Part II is concerned with a study of the role of friction in the behavior of a roof truss. The appendices include laboratory tests by the author.

Jan 1, 1979

By Richard W. Knostman

A study was made of the factors affecting lead and zinc production in the Pacific Northwest. Costs, ore reserves and potential resources, and domestic demand were analyzed. It was concluded that a projected 3.1-percent average annual increase in U.S. demand for zinc through 1975 and a corresponding 2.5-percent rise for lead will be supplied mainly from mines in the Eastern and Central States. Annual Pacific Northwest mine production of lead is estimated to fluctuate around 82,000 tons, while zinc output may average 135,000 tons through 1975. Measured, indicated, and inferred reserves in the Pacific Northwest, containing 1.56 million tons of lead and 2.59 million tons of zinc, are more than sufficient to maintain this level of production. Annual production from Pacific Northwest electrolytic zinc plants is expected to increase to over 300,000 tons of slab zinc by 1975. Lead smelters may experience difficulty in maintaining output at 1964 levels.

Jan 1, 1967

This Bureau of Mines investigation addressed two primary issues of air velocity measurement in mines: the determination and use of correction factors, and the development of guidelines for the selection of a suitable site at which the measurements should be taken. Other facets of the investigation included a comparison of measurement methods and devices, and aircourse cross-sectional area measurement. The study consisted of theoretical, laboratory, and in-mine investigations. The measurement devices included in the experimental phase were vane anemometer, vortex shedding anemometer, a prototype thermoan-emometer, smoke tube, and oil of wintergreen sprayer. The measurement methods included single-point centerline, timed-point traverse, continuous traverse for the anemometers, and various distances and cloud positions for the smoke tube and oil of wintergreen devices. The study resulted in guidelines for measurement site selection that are applicable to most inmine situations. It also showed that the use of correction factors is problematic. There are many potential pit-falls and there are cogent arguments against using certain correction factors. However, generalized correction factors were developed that can be successfully applied in routine ventilation work, provided that their use is properly understood.

Jan 1, 1985

By C. P. Mishra

The Bureau of Mines investigated the availability of mercury from 22 deposits in market economy countries. The 15 significant deposits evaluated have demonstrated resources of approximately 25 million metric tons of ore containing 5.3 million flasks of mercury and account for more than 85 pct of the demonstrated resources for market economy countries. Using data gathered as part of its Minerals Availability Program, the Bureau determined the mercury production potential of each deposit. At a January 1984 mercury market price of $300 per flask, the deposits evaluated could economically produce an estimated 2.5 million flasks of mercury from six mines operating at the time of this study; no mercury is available at this price from nonproducing operations. At $600 per flask, approximately 4.5 million flasks of mercury are available. For production costs up to $300 per flask, operating mines could supply mercury at the current production rate of 114,000 flasks per year until 1988, when the amount of mercury available from these deposits would decrease. This decline could be offset by the development of resources currently reported at the identified level (17 million flasks) at much higher production costs.

Jan 1, 1985

By Wilford S. Wright, Harold E. Heide, Robert L. Thorne, Neal M. Muir, Aner W. Erickson, Bruce I. Thomas

A program of investigation of strategic and critical minerals began in 1940 to examine and develop tungsten occurrences in the western United States and Alaska. During the years in which the nation was at war, this work was given special impetus to stimulate domestic production. This report is a compilation of results of the tungsten investigations in Alaska supplemented by certain data made available by the Territorial Department of Mines and is designed to include in its scope descriptions of all known tungsten occurrences in the Territory. Two areas in Alaska warranted special investigation - one at Gilmore Dome, 16 miles northeast of Fairbanks, and the other in the Hyder District, at the head of Portland Canal. Three tungsten properties - the Stepovich, Colbert, and Yellow Pup - are at Gilmore Dome. The Stepovich property, referred to sometimes as the Cleary Hill tungsten deposit, was worked by the Cleary Hill Mines Co. from April 1942 until May 1944 and was first examined by Robert S. Sanford and Norman Ebbley, Jr., engineers of the Bureau of Mines, in September 1942. The Cleary Hill Mines Co. by that time had explored an 800-foot strike length of the ore zone with 10 bulldozer trenches and was sinking an inclined shaft on ore in the central portion of the explored zone. In January 1943, the senior author, in company with Ebbley and Harry C. Doheny, supervising engineer of R.F.C., examined the property. Preliminary work by the Bureau of Mines began in May 1945, but actual exploration did not commence until late in June and continued until the end of October 1943. The deposit was examined by John B. Mortie, Jr., and William C. Overstreet, of the Federal Geological Survey, in 1942, and this study was continued in 1943 by Frank Byors, who also assisted the Bureau’s engineers on geologic problems. A magnetometer survey of this area was undertaken in 1942 by Henry Joosting and Eskil Anderson, engineers of the Territorial Department of Mines, and was completed with Bureau of Mines assistance in 1943. During 1943 the Bureau completed exploratory projects on the Cleary Hill mine and adjacent Colbert prospect. The field work on the Colbert property was begun early in July 1945 and continued intermittently until the end of October 1943, when it was recessed because of subzero weather. During September 1944, the Bureau of Mines established (by means of a few surface trenches) continuity between the Colbert mineralized zone, high on the dome, and the Yellow Pup vein, the lowest known tungsten mineralization in the area. It is generally recognized that any extensive program to develop the area as a whole logically would be carried out from the lower horizon.

Jun 1, 1948

By William S. Roberts

The Bureau of Mines has initiated a program to determine the availability of land for mineral exploration and development in Alaska. Researchers involved in this pro-gram are comparing land availability, based on ownership and government policies and regulations, to the distribution of known mineral deposits and terranes. This report on southeastern Alaska presents the findings of the first of six regional studies that will cover the State. The study consisted largely of data compilation and analysis using various mapping techniques. Summary land availability data are presented on copies of U.S. Geological Survey (USGS) quadrangles at a scale of 1:500,000. Five categories of land availability were identified: open to mineral exploration and development (approximately 9.4 million acres, or 38% of the 24.8-million-acre study area), open but with possible use restrictions (4.2 million acres, or 17%), selected (0.5 million acres, or 2%), patented (0.74 million acres, or 3%), and formally closed to mineral exploration and development (10 million acres, or 40%). Of the 1,187 known mineral deposits in the study area, approximately 38% are on land in the open category. Mineral terranes comprise approximately 6.7 million acres, or 27% of southeastern Alaska. Approximately 34% of these terranes are on open land.

Jan 1, 1985

By Murray Greyson

A number of tests were made with various methanation catalysts in fixed-bed, conventional fluidized-bed, and multiple-feed, fluidized-bed equipment to develop catalysts and processes for methanation of synthesis gas. The results show: 1. Methanation reactions may be carried out in 1-inch, bench-scale equipment at high synthesis-gas throughputs with good temperature control of the reactions if a multiple-feed type of fluidized-bed design is used. 2. Nickel is superior to iron as a catalyst for the methanation of synthesis gas, unless the process is considered in terms of a combined operation that produces both gaseous and liquid products. 3. Techniques of catalyst preparation determine, to a large extent, the process life of nickel catalysts, and these techniques must be thoroughly investigated before any conclusions can be reached. 4. Enough data are available to indicate that the sulfur concentrations in synthesis gas that is used for methanation are extremely critical, and maximum process limits should be carefully evaluated.

Jan 1, 1955

By Ronald P. Hollenbeck

The value of mineral production in Alabama increased 1 percent above the record high set in 1965. Alabama ranked second among the States in the production of bauxite, third in the production of masonry cement, native asphalt, and scrap mica, sixth in the production of portland cement, ninth in the production of iron ore, and tenth in the production of lime. The mineral industry of Alabama was dominated by the mining and processing of coal and stone, the manufacturing of cement, and the production of crude petroleum. These industries accounted for 87 percent of the State's total value of mineral production, compared with 85 percent in 1965.

Jan 1, 1967

By David A. Summers

Coal is increasingly viewed as one of the major fuel resources of this country for the remainder of this century. The need to extract a greater percentage of the coal in a given seam, together with advantages of improved safety, indicates that longwall mining will become more widely used within this time frame. A novel method of mining coal on a longwall face, utilizing high pressure water jets, is herein described. The mining machine proposed will exploit the stress conditions which exist on a longwall panel in order to achieve the required productivity while at the same time reducing respirable dust and methane ignition hazards. The water jets will excavate only the boundary of the extracted seam section, and thus the energy requirement of the machine will be minimized. The action of the machine is similar to that of an existing coal plow, except in that the wedge teeth of the plow are replaced by oscillating high pressure water jets. The machine can, therefore, cut to the depth and at the speed of existing shearer units at equivalent power levels. The removal of impact stresses from the machine will reduce downtime required for maintenance and replacement of picks and lower the load on the haulage motor of the system. The ability of the machine to increase the depth of cut without an increase in horsepower will further improve productivity when transportation systems to remove the greater production are in operation.

Jan 1, 1974

By Jr. Fish

As a part of a study of iron are resources in the Appalachians, 9 diamond drill holes aggregating 1,580.7 feet were drilled in a portion of the Butt Mountain area of northeastern Giles County, Virginia. Three hematitic sand-stone beds were intersected in the Clinton formation but only one was consistent in thickness and grade in all 9 drill holes. This bed averages 18.9 percent iron over an average thickness of 24 feet. The drill cores were logged and chemical analyses were made on 161 individual samples and 22 composite samples. Beneficiation studies were made of three composite hematitic sandstone samples each representing a separate bed containing 14.6, 19.8 and 20.0 per-cent iron. Major mineral constituents of the samples were hematite, quartz, and sericite.

Jan 1, 1967

This manual covers the operation and lubrication procedures for the Eimco Pumpable Roof Bolting Machine. This machine meets U. S. Bureau of Mines Schedule 2G Approval. This manual is divided into three major parts: 1. Machine dimensions; 2. operating instructions and; 3. Lubrication. Whenever front or rear, right or left arc mentioned it is assumed that the reader is standing behind the machine looking toward the boom. The boom is at the front of the machine. Safety When leaving machine parked on an incline turn wheels into the rib or block wheels. Do not run over power cables. Make sure your power cable is up out of the way so others can't run over it. Machine has a fire suppressor system for the power unit. The remote actuator (pressure cylinder) is located at the operator's station. Components and service procedures on page 59.

Jan 1, 1976

By D. B. Gawthrop

"One of the properties of an explosive, of interest to the user, is its ability to transfer detonation across an air gap to another explosive charge. This Property is of particular importance with permissible explosives used in coal mines, since they are relatively insensitive to detonation when compared to many of the commercial dynamites used in metal mining.An essential characteristic of an explosive is that it shall always be sufficiently sensitive to propagate detonation completely. An insensitive explosive constitutes a hazard because of (1) the danger of drilling into unexploded portions of charges of explosives which have partially misfired, and (2) the likelihood of a low order of detonation, or the burning, of all or part of the charge in a hole prepared for blasting. The latter condition not only usually produces large volumes of poisonous gases, but it is particularly hazardous in gassy or dusty coal mines where explosions may result.The Bureau of Mines and manufacturers of explosives determine the sensitivity of explosives to detonation over an air gap by means of a [(halved-cartridge gap test,"" for which the ends of the cartridges of explosive exposed to one another, are cut off. Since in blasting, the crimped ends remain on the cartridges used, this investigation has been made to ascertain the effect of the crimped paper ends on the distance detonation is propagated over an air gap as compared with the propagation distances obtained when the crimped-paper ends are removed."

Nov 1, 1932

By J. Fletcher Smoak

Consumption of abrasive materials in the United States in 1981 was approximately $340 million, of which 37 % was industrial diamond (natural and synthetic), 39% manufactured abrasives, and 24% natural abrasives. Production and shipments of natural abrasives, excluding emery and industrial diamond, decreased in quantity 9% and 7%, respectively, when compared with that of 1980. Emery showed the largest change in output, decreasing 30% in quantity and 20% in value. Production of nonmetallic .manufactured abrasives material plus shipments of metallic abrasives material decreased 5% in quantity but increased 4% in value. Nonmetallic manufactured abrasives consisted of aluminum oxide (fused) and crude silicon carbide produced in the United States and Canada and accounted for 63% of the value of all manufactured abrasives. Metallic abrasives shipments included chilled and annealed iron shot and grit, steel shot and grit, plus cut wire, aluminum, and stainless steel shot and equaled 37 % of the value of all manufactured abrasives.

Jan 1, 1982

By M. J. Pazuchanics

This U.S. Bureau of Mines report presents results from an ongoing investigation of the use of adaptive signal discriminating methods to distinguish between cutting coal and cutting mine rock. Bit-cutting forces and tool vibration were measured in the laboratory as a linear-cutting apparatus (LCA) made constant-depth cuts in coal, sandstone, and shale test specimens. A portion of the collected data has been analyzed and some preliminary results are given here. The influence of data bandwidth, data window size, number of signal features, and voting among classifiers on classification performance are noted. Results to date, based on ideal-cutting conditions and simple geologic materials, indicate that of the four classifiers tested there appears to be no single best classifier. Usually, classification accuracy showed slight improvement as the number of features considered for classification increased. The highest classification accuracies were achieved when voting was conducted among classifiers followed by voting among force components.

Jan 1, 1991

By D. D. Hamilton

The ISMS program provided for the development and demonstration of equipment modifications for improved safety in both conventional and continuous coal mining systems. This report documents the success of the program in identifying accident hazards in underground coal mines with 4-to 8-foot seam heights, in designing modifications to reduce the hazards, and in demonstrating improved safety through extended underground use of the ISMS equipment.

Jan 1, 1977

By Ronald S. Conti

Historically, underground mine rescue teams have received training only in the course of actual emergencies, or in simulated mine environments, usually on the surface, with placards to identify objects and hazards. Also, while U.S. Federal Regulations require all underground miners to walk escapeways and conduct fire drills every 90 days, this does not fully prepare them for the conditions that may be encountered in real escape situations, such as smoke filled entries. This paper describes technology and realistic training simulations that have been identified for the general workforce and mine emergency responders. Of all the technology evaluated by underground personnel, laser lights and lifelines were most beneficial in leading personnel to safety and out of the mine in smoke-filled passageways. These technological advancements can improve the state of readiness for rescue personnel and increase the chances of survival for personnel escaping from underground emergencies.

By Edward E. Johnson

The principal purpose of this study was the development of an engineering and economic model of a hypothetical large-scale open pit gold mining operation. The guiding concept in developing the model was the idea that, through study of a number of such models, it would be possible to evaluate a mineral property and to make reasonable estimates of the benefits to be derived from research in mining and metallurgy. The model by use of a computer is able to produce results easily and quickly when cost factors are varied. Cost factors may be varied as a result of assumptions of improved technology or of assumptions of assuming different approaches or methods to accomplish a particular segment of the mining or processing operation. The discounted cash flow rate of return was used to measure the effect of changes in costs or expected revenue. In this study, assumptions based on past processing practices were made in an effort to reduce costs of processing the ore These assumptions were: (1) Eliminating the low-grade cyanide circuit; (2) reducing the quantity of material to be processed by screening after crushing; and (3) using a combination of assumptions (1) and (2). All three assumptions resulted in reduced capital investment and operating cost that caused substantial increases in the rate of return.

Jan 1, 1968