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By K. Y. Haramy, R. O. Kneisley

This U.S. Bureau of Mines report summarizes a study of large-scale strata response to longwall mining at a western U.S. coal mine. This study utilized surface and subsurface measurements, geologic mapping, in situ stress measurements, and pressure cell readings to characterize strata behavior. Preliminary analysis of surface subsidence and time-domain reflectometry (TDR) was used to determine a suggested main roof caving sequence. Coal ejected from the face apparently resulted from brittle failures that occurred because of lack of significant yield zone development. The combination of a strong coal with pronounced directional behavior, low overburden pressures, a good caving roof, and a high-production environment that minimized time-dependent loading apparently reduced yielding of the longwall face. The panel 1 headgate-entry design appears adequate; however, the abutment pillar and adjacent panel tailgate rib are highly stressed and may contribute to problems during second panel mining. The small chain pillar yielded after passage of the face, but the pillar width may be near maximum since evidence of a stressed core exists.

Jan 1, 1992

By E. O. Wagner, A. W. Koth, V. F. Parry, J. B. Goodman, D. C. Gernies

"INTRODUCTION A commercial-scale pilot plant for gasification of lignite was completed by the Bureau of Mines at Grand Forks, N. Dak., early in 1945 as an extension of work on, gasification of low-rank coals initiated in a smaller pilot plant at Golden, Colo., during 1943. The development work on this plant was part of a program to make reducing gases from lignite for beneficiation of low-grade iron ores. The background of this project has been described in a previous report. 6/ The present report describes the major features of the large pilot plant, a record of experimental operating data during five runs totaling about 1,800 hours, .and results of experimental work on the small pilot plant at Golden during 1945.This project has created considerable interest because heretofore there has been little success in several attempts to gasify American lignites.Furthermore, the methed employed is a departure from conventional processes. Natural lignite is fed continuously into an externally heated annular retort and is converted into water gas by heat conducted through alloy metal walls. Because of the high thermal conductivity of metal, the rate of gasification is several times greater than can be obtained when employing refractory walls. The process has been developed to a part that leaves one major question unanswered. - ""How long will the alloy last under practical operating conditions?"" - and this question has aroussed the interest of the Coal Division of the Bureau of Mines in this new development.Owing to the high reactivity of the lower-rank fuels, the water-gas reactions proceed rapidly at medium temperatures of 1,650°F. to 1,800°F. These temperatures can be attained in a reaction zone heated by external means when the temperature of the retort does not exceed 1,900°F. while transferring from 6,000 to 7,000 B.t.u. per hour per square foot. Such rates are several times greater than can be attained through refractory walls as employed in the Didier-Bubaig 7/ and the Ahrens processes. 7/ Therefore, the investment cost of the gas generator per unit of capacity will be considerably lower for the higher-capacity process. However, the maintenance cost of metal vessels will be higher than that of refractory retorts, and this emphasizes the importance of large-scale operation to determine the life of an alloy retort under practical operating. conditions."

Sep 1, 1947

By W. A. Cole

This report covers the preliminary phase of an investigation of some clays and shales and other materials in North and South Dakota to determine the feasibility of lightweight -aggregate manufacture in the two States. The background of the light - weight -aggregate industry, on a national basis, and results of preliminary laboratory testing of samples of North and South Dakota clays and shales from various localities are presented herein. The countrywide search for lightweight aggregates was necessitated toward the end of the 19th century by the change in building design from thick, heavy, load- bearing walls to a framework of structural steel .beams and columns with thin walls, followed shortly by the use of reinforced concrete and structural concrete as materials for the load-supporting frame. Ordinary concrete, with sand and gravel aggregate, weighs about 150 pounds to the cubic foot. A lighter concrete was needed to relieve the dead load and make it possible to construct higher buildings or add stories to existing buildings.

Jan 1, 1954

By E. Don Dilling, W. F. Holbrook, Lloyd R. Michels, James W. Pennington, Dwight L. Harris, Wm. F. Hergert, Cyrus L. Blogett, H. A. Doerner, Ernest A. Reige

"IntroductionA process for production of magnesium by carbothermal reduction was developed at Padentheirm, Austria, by the Austro Americanische Magnesit Corporation& an independent investigation of this and other processes was started in 1937 by the Bureau of Mines at Pullman, Wash., with the cooperation of Washington State College. 10/ A preliminary study of the Radentheirm pro¬cess, as revealed by the meager information then available, demonstrated the following two major disadvantages,The use of hydrogen for shock cooling requires an enormous volume of gas - about 1,000 cubic feet for condensing each pound of metal as a pyrophoric dust which must be completely separated from this gas. Then if the gas is to be recycled for repeated use, the CO produced by the reduction reaction must be separated from the hydrogen. These separations are costly from the standpoint of equipment and operation. 11/The condensate is an impure, pyrophoric metal powder that must be purified and converted to coherent form. This is accomplished by distillation or sublimation of the metal. Distillation on a large scale involves difficulties inherent in the high boiling point (1,107° C.) and the chemical activity of the metal. To avoid these difficulties, the metal is sublimed at 600° C. and of very low pressure. This is quite easily carried out as a batch operation but is a costly procedure. A continuous sublimation process has not been accompli shed."

May 1, 1945

By A. J. Farstad

Characteristics of metal/non metal mines were evaluated to determine the suitability of applying the U.S. Bureau of Mines electromagnetic location system to the problem of locating trapped mines in metal/non metal mines. Statistical distributions of mine depths and overburden conductivities show that the existing USBM EM system is inadequate for most metal/non metal mines. Alternate approaches to trapped miner location in deep mines were identified and subsequent field tests were conducted at six (6) mines to evaluate their feasibility. The approach considered to be the most promising is one which utilizes the existing manpack transmitting system, modified slightly for a dual frequency output, in conjunction with a sophisticated signal processing receiver on the surface. The main advantage of staying with a "through the earth" approach is that the underground equipment can be kept simple, easily maintained, light-weight and inexpensive.

Jan 1, 1979

An accelerated and coordinated program of coal research is believed by many to be a necessary step in assuring coal's proper position in the expanding energy market. The President's Advisory Committee on Energy Supplies and Resources Policy, for example, made the following recommendation: We recognize that coal is a great national asset and endorse a cooperative study to determine what research and development could be undertaken. The coal industry and both Federal and State Governments should participate in this study and its costs. Representatives of the coal industry have agreed that such a study should be initiated. Accordingly, Felix E. Wormser, Assistant Secretary - Mineral Resources, United States Department of the Interior, requested the Bureau of Mines and Bituminous Coal Research, Inc., to conduct a survey of current research on bituminous coal. In addition to this survey, studies were made to determine research projects that would be of value to the coal industry.

Jan 1, 1956

Studies of coal reserves have shown that the total augerable reserve base for the United States is estimated to be five billion tons under the current state of mining technology; the potential reserve base at 850-ft penetration is estimated at 20 billion tons. It is with the idea of improving coal recovery, a basic objective of Project Independence, that new concepts, such as modifications and improvements in current machines and development of ways to recover pillars left by current augering, are required. Unless recovery is improved, these potential reserves amount to lost coal.

Jan 1, 1975

By David E. Siskind

The U.S. Bureau of Mines and the State of Indiana cooperated with AMAX Coal Co. and its consultants to determine the effects of coal mine overburden blasting on nearby pipelines. Five pressurized 76-m pipeline sections were installed on the Minnehaha Mine highwall near Sullivan, IN, for testing to failure. Four 17-to 51-cm-diameter welded steel pipes and one 22-cm PVC pipe were monitored for vibration, strain, and pressure for a period of 6 months while production blasting advanced up to the test pipeline field. In contrast to previous studies of small-scale, close-in blasting for construction, these tests involved overburden blasts of up to 950 kg per delay in 31-cm blastholes. Analyses found low pipe responses, strains, and calculated stresses from even large blasts. Ground vibrations of 120 to 250 mm/s produced worst case strains that were about 25 pct of the strains resulting from normal pipeline operations and calculated stresses of only about 10 to 18 pct of the ultimate tensile strength. No pressurization failures or permanent strains occurred even at vibration amplitudes of 600 mm/s.

Jan 1, 2010

By Manuel Gomez

This report presents prediction equations for 12 variables that are indicative of metallurgical coal quality. The variables include six for coke strength and six for carbonization product yields. All variables were predicted for coking coals having volatile matter contents from 16.3 to 42.1 percent, dry basis. The prediction equations, developed by mathematical-statistical techniques, were based on information from the proximate and ultimate analyses, the size consist, and the petrographic composition of bituminous coals carbonized in BM-AGA retorts at 800°, 900°, and 1,000° C. The equations were evaluated for validity with independent data derived from the 900° C carbonization of 33 binary blends of various coals and 22 binary blends of Pocahontas No. 3 low-volatile bituminous coal with 11 high-volatile bituminous coals. Results show that metallurgical coal quality can be predicted ahead of mining because data used to derive the prediction equations can be obtained at the time of exploration. Capability to forecast coal quality is useful in mine planning and should provide basic information for optimization of blending and crushing techniques and thus lead to the production of uniform coke.

Jan 1, 1970

By J. W. Thompson

CONSTRUCTION OF STATUTE-SALE BY ENTRYMAN. The timber and stone act (20 Stat., 89) does not forbid an entryman from alienating his interest in his claim; but the act makes illegal any prior agreement by which the entryman acts for another in the purchase. Worden v. United States, 204Fed., 1, p. 4, April, 1913. ASSUMPTION OF DEBT BY GRANTEE-LIABILITY TO CREDITOR OF GRANTOR. A grantee of a mine who agrees to pay the grantor's debts in part payment of the purchase price of the mines becomes to that extent the principal debtor, and the grantor becomes the surety, and the grantor's creditor may in equity enforce his claim against the grantee of the mine, and the grantor in such a case is not a necessary party. Silver King Coalition Mines Co. v. Silver King Consolidated Mining Co., 204Fed., 166, p. 169, April, 1913. RIGHT OF COTENANT TO MINE AND SELL. A cotentant in exclusive possession' of mining property who extracts and sells ore is entitled to charge against the proceeds of the sale the reasonable and necessary expense of its extraction and marketing, as in such case the cotenant is not a trespasser.

Jan 1, 1914

By R. Duncan Gardner

This paper describing the milling practice at the concentrator of the Harmony Mines Co. is one of a series being; prepared by the Bureau of Mines on milling methods and costs in the United States. For the period February 15, 1929, to June 1, 1929, the concentrator treated 200 tons of copper ore per day containing 3.84 per cent copper and recovered 99.2 per cent of the total copper in concentrates averaging 26.61 per cent copper. Milling practice at the Harmony Mines is in most respects similar to the usual practice at the average flotation concentrator producing bulk flotation concentrates. The exceptionally high recovery is due to a number of minor conditions. These minor details will be stressed throughout this paper.

Jan 1, 1930

During the period 1979 thru 1982. Multi Mineral Corporation conducted a mining research program at the United StAtes Department of the Interior's Bureau vi Mines Oil Shale Mining Environmental Research Facility in the Central Piceance Creek Basin, Rio Blanco County, Colorado. The program consisted of mining, environmental and geotechnical research data and. the results are described in this report.

Jan 1, 1983

By H. Tomlinson

"PURPOSE OF REPORTFatalities from falls of roof and coal are responsible for the death of more than 1,000 miners annually in the bituminous coal mines of the United States or practically one—half of the total fatalities in and about these mines. The men are killed by falls singly or in small groups and little or no publicity is given these accidents as they lack the spectacular features of gas and dust explosions. As a result, the public and even the miners have the impression that accidents from falls of roof and coal are just one of the unavoidable hazards of the coal—mining industry. This belief is not true. Accidents caused by falls can be avoided largely by the application of sound engineering principles, by education, and by proper leadership in the industry, just as gas and dust explosions and accidents caused by explosives have been reduced in recent years.The necessity for studying falls of roof and coal becomes apparent by referring to the following data from a table by Adams and Chenoweth:3"

Jan 1, 1933

Continuously monitor and record respirable dust levels underground by a reliable, sensitive, and fast-response device. Approach A light-scattering photometer, having a LED (Light Emitting Diode) light source and other significant improvements, has been designed and incorporated into a portable continuous monitor. How It Works The monitor continuously draws air into the sampling inlet through a cyclone that removes dust particles larger than respirable size. The dusty air enters the photometer vertically downward through a cylinder which is intersected by the optical system. (This cylinder appears as a circle in the drawing of the photometer.) The center of he column of dusty air intersects a beam of pulsing light from the LED, causing some of the light to be reflected, scattered, and refracted. Only the light that is scattered at an angle of about 700 from the light beam passes through a lens to the photodetector which generates an output voltage Signal proportional to the dust content in the air. This signal is detected, amplified, and converted to a digital readout directly in milligrams of dust per

Jan 1, 1979

By B. F. Naylor, C. H. Shomate, F. S. Boericke

"Ilmenite is the most important titanium-bearing constituent of titaniferous iron ores. Such ores, of which the United States has abundant reserves, are of interest because they constitute an important potential source of both iron and titanium that may be tapped in times of stress, and which eventually may be utilized in the normal course of events.As the iron and titanium constituents of titaniferous iron ores are not completely separable from each other by ore-dressing methods, any process for metal recovery will, of necessity, involve reduction of the iron in ilmenite. Consequently, knowledge of the thermodynamic properties of ilmenite should supplement information already available concerning those ores. With this in view, the Pacific Experiment Station of the Bureau of Mines undertook to evaluate thermodynamic properties; the data obtained are the subject of this report.Three types of experimental work were involved. First, low-temperature specific heats of ilmenite were measured in the temperature range 500 to 29S° K. These data serve to evaluate the entropy, a quantity necessary for a reliable evaluation and correlation of other thermodynamic properties. Second, high-temperature heat-content measurements were made in the temperature range 298° to 1,743° K. The data serve to bridge the gap between room temperature and elevated reduction-process temperatures. Finally, hydrogen-reduction equilibria were measured in the temperature range 1,220° to1,375° K. These data-give a direct measure of the free energy of reduction of ilmonite at these temperatures and, in conjunction with results of the other two types of measurements, serve to obtain the heat of formation of ilmenite, a quantity not readily determinable by direct calorimetric means.The data are correlated to form a composite, self-consistent portrayal of the thermodynamic properties of ilmenite, which may be used in evaluating the efficacy of any reducing agent of known thermodynamic properties. Selective-reduction of iron in ilmenite by hydrogen, carbon monoxide, and carbon are considered in this report."

May 1, 1946

By M. N. Rubin

This report summarizes the work performed under USBM contract J0100018. The purpose of this work was to document the currently available noise control techniques that can be incorporated into new coal preparation plants during the design stage. This was accomplished by reviewing the related experience of the contractor and subcontractor (Bolt Beranek and Newman Inc.), conducting an extensive literature search, visiting operating coal preparation plants, and contacting various equipment manufacturers. The treatments addressed include equipment substitution, changes in plant layout, and retrofit treatments for existing equipment.

Jan 1, 1982

By Steven E. Mischler, Jon C. Volkwein

A diesel particulate matter analyzer capable of direct, real-time measurement of engine exhaust particulate is necessary to effectively institute source control technology currently being used on diesel equipment and to ensure that the control measures are working. To investigate the potential of a differential pressure monitor to measure diesel particulate matter in undiluted exhaust, samples were collected from three different diesel engines-Kubota, Isuzu, and Deutz-running under 12 different RPM and load scenarios. These measurements were compared to elemental carbon concentrations in the sampled exhaust as determined by using the NIOSH 5040 analytical method. Elemental carbon is used as a surrogate measurement for diesel particulate matter. The results of the two data sets were then compared using a linear regression analysis. The coefficient of determination (or R2) was calculated to be 0.98, 0.94, and 0.74 for the Kubota, Deutz, and Isuzu engines, respectively. R2 values of this magnitude indicate that this method can be successful in estimating elemental carbon emissions in the engines tested. In addition, for replicate samples, the coefficient of variation ranged from 7.1% to 10.2% with an average of 8.5%. These data indicate that this method could prove useful to mechanics as they work to maintain engines and DPM control technologies.

By Steven J. Page, John A. Organiscak

Laboratory crushing experiments were conducted on a range of low- to high-volatile bituminous coals to investigate the various factors influencing airborne respirable dust (ARD) generation. This research was conducted to identify the principles of ARD liberation from the coal product. Five U.S. bituminous coals were uniformly prepared and processed through a double roll crusher located in a low-velocity wind tunnel. Experimental factors studied included inherent coal seam constituents, coal grind ability, specific energy of crushing, product size characteristics, dust cloud electrostatic field, and specific ARD generated. The results of this investigation indicate that a combination of several factors are associated with ARD generation. One factor is the effect of coal rank, described by the inherent moist fuel ratio, on the product size characteristics, defined by Schuhmann size function parameters. Another key factor is the effect of air dry loss(ADL) moisture in the coal seam on the breakage-induced electrostatic field of airborne dust. The effect of these factors is that different percentages of <10-m coal particles are dispersed as ARD. A discussion of electrostatic field principles, coal ADL, and its effect on ARD generation is presented.

Jan 10, 1998

By P. R. Jones

A computer program was written for design and cost of a shell and tube heat exchanger in which the total cost, which includes annual fixed charges and annual operating costs, was minimized. The program was written for the type of heat exchanger in which only the tube side pumping costs were significant and for triangular pitch, single or multiple pass, heating or cooling, and no change in phase. Tube diameter was not optimized since the tube dimensions do not affect the cost very much. However, the tube dimensions do affect the shell diameter, number of tubes, and length of tubes; and price optimum design was obtained for four standard tube diameters. Standard heat exchangers having at least the required area are also listed. The program was made adaptable to various fluids and to various tube dimensions by including many of the required data such as physical properties of the fluids, tube data, and standard shell data as input data.

Jan 1, 1969

By W. P. Huleatt, Jr. Traver, Jr. Hazen

"Vanadium and uranium occur widely distributed throughout western Colorado and eastern Utah, and a few deposits have been found in northeastern Arizona and northwestern. New Mexico. The area in which it occurs includes approximately 10,000 square miles and is generally referred to as the vanadium region of Colorado and Utah.The majority of the deposits consist of replacement bodies and impregnations of rare minerals in the lower Morrison formation of Jurassic age. The ore bodies are flat, with irregular margins, and most of them conform to the stratification.The ""rim rock"" topography of the region includes many steep-walled canyons and plateaus, which afford an abundance of outcrops that have been responsible for most of the discoveries of mineralized areas. Delimitation of ore bodies within the areas is accomplished most effectively by core drilling from the surface.The deposits were discovered in 1899 and from 1911 to 1923 wore worked extensively for radioactive uranium ores, principally carnotite.The discovery and marketing of the richer and more cheaply mined pitch-blende ores of the Belgian Congo left the Colorado-Utah deposits without economic importance as sources of radium and uranium, and the region became inactive in 1923. After a period of comparative inactivity, the rising demand of the alloy-steel industry for vanadium renewed interest in the deposits, which were known to contain that metal. By 1938, vanadium production in the area had achieved respectable proportions, and new impetus was given to it by the United States’ entry into World War II in December 1941. In 1942, new treatment plants for vanadium ores were completed in Monticello, Utah, and Durango, Colo. In order to meet the requirements of these and other plants in the region, it became necessary to open new vanadium mines and prepare old onus for production.In an effort to stimulate mining, the Metals Reserve Company initiated a stock-piling program and appointed the united states Vanadium Corporation, to act as its purchasing agent.The extra production was expected to come largely from small, independent operators whose limited funds did not permit them to maintain development and exploratory programs. Study of conditions made it apparent that extensive exploration would be necessary to sustain production, and accordingly the Bureau of Mines initiated an exploratory drilling project on a cooperative basis with the Geological Survey. The principal objects of the work were to enlarge the known ore reserves of the area and, if possible, discover new ones. The results have been gratifying in both respects."

Sep 1, 1946