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By W. L. Dare

This information circular is one of a series the Bureau of Mines plans to publish describing the methods and costs of mining uranium on the Colorado Plateau. The Temple Mountain mining district is unique among the uranium-producing areas on the plateau. This relatively isolated mining district is in Emery County, Utah, on the eastern flank of the San Rafael Swell, about 35 miles southwest of the town of Green River. The district lies just within the eastern escarpment of the San Rafel Reef - a rampart of rugged and tilted sandstone cliffs that encircles the highly eroded core known as the Sinbad Country. The presence of petroleum matter found associated with the ore deposits, the occurrence of uranium in various formations, and the structural deformation caused by collapsed features have aroused a great deal of geologic interest. Mine development on Calyx Flat is distinctive, in that the ore deposits are worked through 36-inch calyx-drill holes.

Jan 1, 1957

By Luis Noval Noval García

El objetivo de la ventilación es desarrollar una atmósfera saludable, segura y apta para la realización del trabajo por parte del personal. En ese sentido, el presente texto señala los gases como problemas comunes presentados dentro del ambiente minero tales como asfixia por anoxia (caso de inhalación) intoxicación, envenenamiento y muerte (letal) e inflamación y explosión (Productos). Para eliminar estos riesgos se debe eliminar las causas a través de una buena ventilación. Asimismo, es necesario conocer las propiedades de los gases, disponer de equipos para detectar su presencia y procurar los medios para eliminarlos.

Sep 1, 1984

By R. D. Groves

Techniques were developed for preparing metallurgical-grade copper powder from industrially produced cement copper. Flotation was used for rejecting discrete gangue particles, acid leaching to remove residual iron and aluminum, hydrogen reduction to eliminate oxygen, sintering to consolidate the fine-sized copper, and grinding to obtain copper powder. Powders prepared from six different cement copper samples contained, in percent, 98.5 to 99.0 Cu, 0.10 to 0.05 Fe, 0.10 to 0.08 insoluble material and the remaining individual impurities less than 0.15 percent. The apparent density, flow characteristics, and other physical properties were suitable for powder metallurgy applications. An economic evaluation showed that this process was economically feasible. Processing costs appeared modest when considering that copper powder commands a price normally about 17.5 cents per pound over that of electrolytic copper.

Jan 1, 1971

This report is the first in a "final" series of publications on the Juneau Mining District (JMD). This volume summarizes the results of Bureau of Mines (Bureau) investigations in the JMD during the period 1984-1988. Volume 2 consists of a detailed description of Bureau investigations of mineral de-posits, prospects, and occurrences. Volume 3 is a report on industrial minerals within the district. This study has identified and examined more than 300 mines, prospects, and occurrences containing gold, silver, copper, zinc, lead, nickel, cobalt, tungsten, molybdenum, chromium, and PGM. More than 20 of these were discovered during this study. An additional 20 prospects not mentioned in the literature were rediscovered during the JMD study.

Jan 1, 2012

By Ann G. Kim

Studies on the initiation and propagation of mine fires have dealt almost exclusively with coal. It has been assumed that the self-heating potential of carbonaceous shales and coal wastes is relatively low. However, in abandoned coal mines and waste banks, initiation and propagation of fires may be strongly dependent on the self-heating tendency of these materials. The purpose of this study was to compare the self-heating probability of carbonaceous shales and coal wastes to that of coals. This study utilized a modified differential thermal analysis method, in which the combustion furnace temperature was the reference to which the sample temperature was compared. Based on the distribution of the maximum temperature differential and the sample heating rate, a self-heating probability value (SHPV) was calculated that corresponded to observed self-heating behavior. In this study, several of the carbonaceous shales and one coal waste had relatively high SHPV. The SHPV did not correspond directly to heating values or to differences in sulfur concentration.

Jan 1, 2010

By T. T. Tomimatsu

This? Bureau of Mines paper discusses the corporate structure dynamics, methods of financing, and financial assessment approaches that should be utilized to evaluate the economic health of the coal industry. It suggests rates of return and other measures of corporate economies necessary to attract capital required to finance emerging coal demand, plus impact of coal sales to total revenues. The study illuminates the activities of 30 selected coal-producing companies, including their subsidiaries or affiliates, that were responsible for approximately 60 percent of the total U.S. production in 1974. The selected firms are not all primary coal producers; many of the larger producer's are classified by the financial institutions as petroleum, metal, and steel producers, public utilities, or chemical industries. The bituminous coal industry is highly competitive as to price, service, and quality of pronuct and is subject to competition from other noncoal energy sources. The top 15 bituminous coal-producing companies mined about 46.6 per-cent of the Nation's total production in 1974, and the balance of approximately 3,885 companies were responsible for the rest of the production. Thus, the U.S. bituminous coal industry is not an oligopoly. Today, about 65 percent of the Nation's total coal production is consumed by electric power utilities and 26 percent by steel, space heating, and other industries; the balance of 9 percent is exported.

Jan 1, 1976

By Mark W. Booth

THIS paper deals with the subject of inbye power as the mechanical . engineer sees it, and invites discussion, particularly from the electrical engineer. At the outset, it will be necessary to clear the ground a little by some definite statements. In this question of compressed air versus electricity for the transmission of power and driving of machinery in underground workings, we must see that there are definite fields that compressed air on the one hand, and electricity on the other, can fill to much greater advantage than the other, and in which there can be little or no direct competition, at least for the present. It is under conditions where these fields overlap, and as to where the line must be drawn between the two, that the respective merits of each must be considered. Steam was the first means used to transmit power from the surface of a mine to drive underground machinery, and so long as distances were short and means possible to ensure fairly efficient use of the steam, and where the fire hazard was not in evidence, it gave fairly efficient service. I have in mind an instance during my own connection with the mines-a duplex pump at the shaft bottom at Princess colliery, driven by steam, and which used the steam compound and condensing; and, but for the mechanical difficulties, it was a not inefficient proposition. The steam was taken direct from the surface boiler-plant through a line down the shaft, and used directly at the pump, being in effect a straight conversion from coal to steam to work done. It was the mechanical arrangement, and failure of the pump in that direction, that led to its removal and replacement by something better in the way of an electrically driven turbine pump. Given modern mechanical arrangements, such as a steam-turbine drive on a high-speed turbine pump, and all other parts made in accordance with best practice in the art of steam generation and use, a steam-driven unit fully as economical would have been obtained. But the central electric supply station, and all that that means or promises (not always the same), turned the scale against steam.

Jan 1, 1936

By Mark Rybak

On Aug. 31, 2006, Tropical Storm Ernesto hit the city of Richmond, VA. The Battery Park area was hit particularly hard, as flooding forced an evacuation of the area. A large sinkhole collapsed a sewer line in the Battery Park area, blocking the pipe and causing more serious flooding. This article describes the fast track design, bidding and construction of an emergency tunnel to bypass the collapsed sewer. Innovative value engineering, tunneling and shaft-sinking methods and final lining design all contributed to the success of this project. The storm inundated Richmond, VA with up to 305 mm (12 in.) of rain that, in some areas, caused widespread flooding and damage. One of the hardest hit areas of Richmond was Battery Park. A major trunk sewer in the Battery Park area collapsed and caused local combined sewer and stormwater flooding. The collapsed sewer was a 2.4-m x 76-mm (8-ft- x 3-in.-) wide by 2.7-m- x 152-mm- (9-ft- x 6 in.-) high arch sewer that was constructed in the 1920s and later filled over with municipal solid waste and a soil fill cap to cur-rent elevations. A sinkhole was created in the area of collapse approximately 18 m (60 ft ) deep and 31 m (100 ft) in diameter. This caused the existing arch sewer to become blocked. As a result of this blockage, contaminated floodwaters reached depths in low-lying areas in excess of 8 m (25 ft).

Jan 1, 2008

By F. H. Gibson

An investigation was made by the Federal Bureau of Mines of methods for determining phosphorus in coal, coal ash, and coke ash. Several of these methods are being considered for international standardization. As might be expected, methods and proposals from other countries for determining phosphorus differ considerably from those accepted an standard in the United States. Some of the methods differ fundamentally in principle from the American Society for Testing Materials (ASTM) standard used in the United States; others differ only in details of procedure. Because the Bureau considered that certain of the proposed methods might offer advantages in obtaining increased accuracy and precision or in decreasing the time required for making analyses, these methods were investigated, and the results compared with those obtained by the ASTM method. The methods investigated may be grouped into three types--volumetric, colorimetric, and gravimetric. All were about equally accurate and may be used alternatively. From a practical viewpoint, when only a limited number of analyses are made intermittently, the gravimetric procedure probably is the most suitable because no special apparatus or standard solutions are required. The volumetric methods are more rapid when more analyses are made. For mass production, the colorimetric methods, although requiring a suitable photometer or spectrophotometer, are more suitable because a large throughput should be feasible.

Jan 1, 1961

By John B. Gayle

A new, experimental coke oven was installed at the Southern Experiment Station, Tuscaloosa, Ala., in 1948. This oven, designated as the Tuscaloosa oven, features a 17-inch carbonizing chamber, globar heating elements, and silica-brick heating walls designed to simulate as closely as possible carbonizing conditions in commercial, slat-type coke ovens. Zoned heat-input arrangements maintain uniform temperatures over approximately 95 percent of the total flue area. The reasons for constructing an oven of this size, the details of the design, and the operating characteristics of the oven were given in an earlier publication.2/ This report presents the results obtained from the first series of carbonizing tests on Alabama coals with the new oven. Factors leading to the development of standardized operating and testing procedures and the results of crosscheck determinations with a commercial oven producing foundry coke are included also.

Jan 1, 1954

By John Paul Gries

During World War II, when the curtailment of imports led to an unprecedented demand for domestically produced mica, beryl, and other pegmatitic minerals, the Bureau of Mines and the Geological Survey entered upon a program designed to expedite the production of these minerals from the Black Hills area of South Dakota. The program involved mapping, sampling and drilling many pegmatite dikes found in the southern portion of the area and beneficiation tests in the field and in the Bureau of Mines laboratories at Rapid. City, S. Dak., Rolla, Mo., Salt Lake City, Utah, and College Park, Md. This paper describes the mode of occurrence and the sampling and beneficiation tests on one dike, the Helen Beryl pegmatite, which was investigated as part of the general pegmatite study in South Dakota. Investigation of the Helen Beryl Pegmatite by the Bureau began in August 1943 and was terminated in April 1944. During this period the Bureau took a series of bulk samples from pits for beneficiation tests, drove an adit through the center of the dike to obtain feed for a bulk-sampling plant operation, and finally drilled a series of long holes to sample the deposit further. Geologists of the Federal Geological Survey mapped the deposit and the faces of all excavations and logged drill holes from sludge samples recovered from long-hole drilling.

Jan 1, 1949

By Tulu B. Ihsan, Mark A. Van Dyke, Ted M. Klemetti

"How well do current modeling procedures calculate the rear abutment extent and loading? Does an improved understanding of the rear abutment extent warrant a change in standing support in bleeder entries? What is the optimal standing support for bleeder entries separated from the longwall startup room by a barrier pillar? To help answer these questions and to determine the current utilization of standing support in bleeder entries, four bleeder entries at varying distances from the startup room were instrumented, observed, and numerically modeled. This evaluation was intended to determine the rear abutment extent and magnitude at various locations to optimize standing support in these entries and those under similar conditions. This paper details observations made by NIOSH researchers in the bleeder entries of a deep cover longwall panel; specifically data collected from instrumented pumpable cribs, observations of the conditions of the entries, and numerical modeling of the bleeder entries during longwall extraction. The primary focus was on the extent and magnitude of the abutment loading experienced by the standing support. As expected, the instrumentation of the standing supports showed very little loading relative to the capacity of the standing supports—less than 25 tons load and 1 inch convergence. The observations of the conditions showed little to no change from before the longwall panel extraction began to when the panel was more than 50% extracted. In addition to the observation and instrumentation, numerical modeling was performed to evaluate the bleeder design. The Flac3D program was used to evaluate these four bleeder entries using previously defined modeling and input parameter estimation procedures. The results indicated only a minor increase in load during the extraction of the longwall panel. The model showed a much greater increase in stress due to the development of the gateroad and bleeder entries, with about 80% of the increase associated with development and 20% with longwall extraction. The Flac3D model showed very good correlation between expected gateroad loading during panel extraction and those expected based on previous studies. The front and side abutment extent modeled was very similar to observations from this and previous panels with similar conditions. The results of this study showed that the rear abutment stress experienced by this bleeder entry design was minimal. The convergence measured in these bleeder entries was small enough not to mandate any additional support beyond development even by U.S. or Australian standards. The pumpable crib load and convergence experienced depends on the geological setting, mining geometries, and timing. The farther away from the startup room, the lower the applied load and smaller the convergence in the entry if all else is held constant. Finally, the numerical modeling method used in this study was capable of replicating the expected and measured results near seam."

Jan 1, 2017

By Miro Mihelich

The mines and prospects in the vicinity of Landlocked Bay, 25 miles southwest of Valdez, Alaska (fig. 1), were examined, mapped, and sampled in July and August 1955 as part of a comprehensive investigation by the Bureau of Mines of ore deposits adjacent to Prince William Sound. The purpose of the investigation is to establish and record the location, nature, extent, and metallurgical characteristics of copper and associated metallization in the Prince William Sound district and to indicate, if possible, those areas in which additional exploration and development may be justified. Of particular interest are the possibly numerous deposits of massive iron sulfides that were neglected during early mining operations. These deposits may constitute important reserves of sulfur and iron. At Landlocked Bay deposits of copper-bearing iron sulfide minerals have been mined or partly explored through mine workings, which are in a zone about 1 mile wide along the western side of a large overthrust fault known as the Landlock Overthrust. Eight of the principal mines along this zone were examined end sampled. Although only three of the mines have a recorded production of shipping-grade copper ore, all have deposits of copper-bearing iron sulfide minerals that are similar in occurrence. The deposits occur as lenticular masses and disseminations of chalcopyrite, pyrite, and pyrrhotite which replace crushed rock or fill cavities along shear zones in greenstones and in sedimentary rocks that are exposed between sea level and an altitude of 2,500 feet. These lenticular masses of sulfide minerals range in size from small pods to ore bodies that have been stoped to maximum widths of 9 feet, strike lengths up to 70 feet, and dip lengths as much as 350 feet. Where accessible for sampling,, the copper content of the deposits ranged from a few hundredths of a percent to over S percent; zinc, gold, and silver are present in negligible amounts. Flotation tests of a sample composited to represent typical mine-run ore indicate that 81 percent of the copper is recoverable in a product assaying 28 percent copper at a concentration ratio of 17.5 : 1. INTRODUCTION Statistical records indicate that approximately 110,000 tons of metallic copper (about 16 percent of total Alaskan production) was produced from mines adjacent to Prince William Sound during the 40-year period ended in 1938. Although the principal production was from a large-scale mining and milling operation on Latouche Island (Kennecott Copper Corp., Beatson mine), a substantial amount of the total copper was derived from direct-shipping ores selectively mined or hand-sorted from numerous other deposits in the district. No production has been made since 1938; many of the claims have long been abandoned, and mine workings are either caved or deteriorating rapidly.

Jan 1, 1957

By John D. Sullivan

In leaching copper ores knowledge of the rate of dissolution of the copper minerals and of the impurities is desirable. With knowledge of these two factors and data as to what minerals are present in the ore the metallurgist has an excellent start on planning a leach¬ing cycle to fit that ore. The rate of dissolution is rather difficult to predict, and the time required to leach a given ore may differ markedly from that required by another ore. The whole study as related to mixed oxidized and sulphide ores is one of relative rates of dissolution of the different copper minerals and the impurities in sulphuric acid and in ferric sulphate. The aim of leaching is to choose a cycle and strength of solvents to ex¬tract a maximum amount of copper and a minimum of impurities. The consumption of reagents per unit of copper dissolved is a function of the strength of the reagents used and the relative rates of attack on copper minerals and impurities. An opportunity may exist of ob¬taining the kind of electrolyte wanted for electrolytic precipitation and yet of saving on the consumption of reagents by modifying the strength of ferric sulphate and of sulphuric acid during the cycle to fit the time needed for dissolving the sulphide and oxidized minerals present. Former papers have considered the rate of dissolution of azurite, malachite, tenorite, chrysocolla, cuprite, chalcocite, boruite, and covellite in common leaching solvents. A paper soon to be written will consider some of the less important copper minerals. The present paper considers the rate of dissolution of copper from ores of the Southwest in sulphuric acid of varying strength and the ratio of sulphuric acid consumed to copper dis¬solved. In this study two ores containing the copper principally in an oxidized condition were used. A study of other ores, especially those containing high percentages of sulphide copper minerals, would be desirable, but since consumption of acid has paramount interest,

Jan 1, 1931

By Walter R. Hibbard

Precipitation in the northeastern United States, Florida, California and in many industrialized areas of the world is now more acidic (lower pH) than can be accounted for by natural causes. At the same time, the acidity of many lakes and streams in the northeastern United States has been measured and found to be similar to that of actual rain. These facts have led to conclusions that the two conditions are related. Coal burning utilities, 700 to 1000 miles upwind, have been accused of being the cause, leading to proposals for strict emission controls on the alleged offenders. The costs of these controls would place an estimated $10 to $15 billion capital burden on utility customers in about 15 states plus $2 to $6 billion annual operating costs. There appears to be no direct well-established scientific evidence that the accused are guilty but that the indictment is based largely on circumstantia1 evidence. This study examines the evidence, describes the situation and proposes what must be done to reduce the acid precipitation in an orderly cost beneficial manner. It is interesting to observe that studies by the different adversaries on the acid precipitation issue come to different conclusions largely because they do not read the same literature, but selectively develop evidence to support their own points of view, This study will try to review the issues impartially and reach a position of scholarly balance.

Jan 1, 1982

By H. M. Harris

The Bureau of Mines investigated chlorination of domestic ilmenites in a fluidized coke bed at temperatures of 950° to 1,150° C. Objectives were to develop an effective process for producing TiC14 suitable for TiO2 pigment and to reduce pollution by collecting and treating waste byproduct chlorides. The reactor for these tests was a 10.2-cm-diam quartz tube heated externally by electrical resistance heaters. It contained coke beds of from 35.6 to 82.5 cm in depth that were fluidized by 13 to 25 l/min of chlorine. Ilmenite concentrate powders were introduced at the bottom of the fluid-bed reactor, using the chlorine gas stream as a carrier. Test results showed that greater than 90 pct of the ilmenite reacted at optimum conditions and recovery of TiC14 ranged from 95 to 99 pct of stoichiometric. A temperature-controlled cyclone was used to remove high-boiling-point chlorides such as MnCl2, MgCl2, and FeCl2, and also collected fine unreacted ilmenite and coke dust. Impure TiC14 and FeC13 were separated by collecting the, iron chloride in a condenser con-trolled at 200° C. Titanium tetrachloride vapor was cleaned by passage-through a salt-column filter followed by condensation in water-cooled and refrigerated condensers. Liquid TiC14 was purified further by well-known industrial methods to meet specifications for pigment-grade chloride. Integrated tests were conducted in which chlorine, produced by dechlorination of FeC13 with oxygen, was recycled and used directly in a fluidized-bed chlorinator.

Jan 1, 1976

By Joel N. Van Sant

The rapidly expanding economy of the West, with its growth of heavy industry, and increased steel production, is primarily responsible for the refractory clay industry's concern over the adequacy of the clay supply in States of the Great Plains and Rocky Mountains. Hence, the investigation by the Federal Bureau of Mines of the occurrence and use of refractory clays in North Dakota, South Dakota, Nebraska, Wyoming, Colorado, Utah, New Mexico, and Arizona has been encouraged by the major consumers and producers of this commodity. The Wyoming investigation is a part of the national program devised to close gaps in the domestic supply of specific types of clays to determine their characteristics and properties and to provide information that will assist the refractory-clay industry. Forty-two locations of clay-bearing rock in 17 areas in Wyoming were examined (fig. 1). Location 3 was not examined during this survey. Its description was taken from an earlier report. Locations 20, 21, and 22 were previously reported but were, also, examined by the Bureau. No samples were collected from these locations because field examination indicated that the shales were not refractory grade. The Hulett, Aladdin, and Newcastle areas are discussed in the section on the Black Hills district; the other 14 areas are described separately.

Jan 1, 1961

By Santosh Kumar Ray, DEBASHISH MISHRA, Niroj Kumar Mohalik, SOMU MANDAL, Jai Krishna Pandey, Asfar Mobin Khan

Coal is a low-cost and high-calorific-value fuel. The coal mining industry worldwide has been suffering from severe accidents due to coal dust explosion hazards since its inception. Statistically, it was observed that 12,489 fatalities had occurred in 104 reported mining accidents from coal dust explosions during 1900–2020. There are numerous methods for detection, prevention, and control of coal dust explosions in mines. The underground mining environment is unpredictable and has an array of variables. These undulating factors make it difficult to prevent or control the coal dust explosion hazard. However, coal mining is done aggressively throughout the world, especially in developing countries as coal is a major source of thermal energy used in power plants contributing to about 38% (IEA, (2019), World Energy Outlook, IEA, Paris https:// www. iea. org/ repor ts/ world- energy- outlo ok- 2019.) of world electricity. Worldwide, coal dust explosibility studies are carried out in experimental mines, laboratories, and simulations. The complexity, lack of proper infrastructure, and unavailability of laboratory equipment sometimes make it difficult to study coal dust explosibility. The authors have discussed in detail and proposed that the CFD modelling can be a viable option for studying and evaluating coal dust explosibility.

Jun 29, 2022

By Jr .. Ebbley

The investigation of mine shafts and underground workings at Leadville, Colo., was started in May 1946 and recessed in November 3, 1946. Thirty-eight shafts and connecting accessible underground workings, comprising about a third of the accessible shafts in the district, were investigated. The Leadville district, a former important producer of lead and zinc, was considered by the Bureau of Mines to be capable of bolstering 'the waning domestic output of .these important metal. Accordingly, the investigation was initiated for the purpose of. .obtaining more definite data on sulfide and oxide reserves, evidence to justify completion of the Leadville drainage tunnel, representative large samples of the complex oxidized and mixed ores for testing to determine methods, beneficiation factual data to be supplied to property owners in order to stimulate production, and to determine the more favorable areas for development by the Bureau.

Jan 1, 1949

By H. L. Gilbert

Zircon sand may be reacted with sodium hydroxide at 600° C. to form sodium zirconate and sodium silicate. Sodium zirconate is water insoluble and so may be washed free of sodium silicate. The sodium zirconate may then be converted to zirconyl chloride by the action of hydrochloric acid and the zirconyl chloride crystals separated by cooling the solution. This approach produces zirconyl chloride of satisfactory purity with less cost than is involved in buying anhydrous zirconium chloride and converting it. A proposed design for a plant is given, INTRODUCTION This work was conducted by the Rare Metals Branch as a part of research on zirconium at the Bureau of Mines Northwest Electrodevelopment Laboratories, Albany, Oreg., under the guidance of S. M. Shelton, Regional Director. The work was supervised by W. W. Stephens, head of the Rare Metals Branch (now with Carborundum Metals Corp.).

Jan 1, 1954