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By R. J. Matetic

The objective of this U.S. Bureau of Mines hydrologic-subsidence investigation was to evaluate the effects of longwall mining on the local ground water regime through field monitoring and numerical modeling. Field data were obtained from multiple-position borehole extensometers (MPBX's) that were used to measure subsurface displacements. Survey monuments were installed to measure mining-induced surface deformations. Numerous drawdown and recovery tests were performed to characterize hydrologic properties of the overburden strata. Coreholes were drilled above the study area to determine lithologic and strength characteristics of the overburden strata using the rock samples collected. Electronic recorders were installed on all monitoring wells to continuously monitor ground water levels in coordination with mining of the longwall panels. A combined finite element model of the deformation of overlying strata, and it's influence on ground water flow was used to define the change in local and regional water budgets. The predicted effects of the postmining ground water system determined by the model correlated well with field data collected from the fieldsite. Without an infiltration rate added to the model, a static decrease of 3.0 m (10 ft) in water level would occur due to mining of both longwall panels and if an infiltration rate was inputted in the model, no predicted long-term effects would occur to the ground water system.

Jan 1, 2010

By G. W. Jones

[A survey of the Ii terature reJ.l....ting to iE;li tion temperatures of acet-ylene-air and acetylene-oxygen mixtures reveals rather '.'fide disagreement in the reported results. In SO!':1e instances the i ition temperatures of acet?-ylene-air mixtures were reported to be lower than those of acetylene-oTjgan mixtlU'es, which is contrary to experience 'tri th other combustibles. ':10 clea.r up some of t!le reported discrepancies, the authorn have icvestigated the igni tion temperatures of acetylene both in air anri oxygen, and their results are presented in this report.]

Jan 1, 1941

By Jerry Olson

The Bureau of Mines (Bureau) conducted a mineral resource investigation of the French Creek-Patrick Butte study area, in west central Idaho during 1989. No mineral resources or significant occurrences were identified. Other than small scale placer gold, no mineral production is known or recorded. At least 100 lode and 150 placer claims have been located in the study area. Most of the area was examined by ground or areal surveys, and 110 lode and 60 placer samples were taken. Four lode prospects were examined in detail, and all placer claim locations were sampled.

Jan 1, 1991

By J. T. Dunham

The Bureau of Mines studied by dilatometry the effect of titanium on the thermal expansivity of hot-rolled zinc and Zn-l percent Cu alloy. The titanium content of the alloys was varied up to 0.3 percent. Expansion coefficients were determined from measurements made both parallel and perpendicular to the plane of the rolled sheet. Titanium reduced expansion parallel to the plane of the sheet, especially in the rolling direction, but increased expansion perpendicular to the sheet. Basal-plane pole figures showed that the degree of preferred orientation increased with the titanium content in the alloy, and that anisotropic expansion can be correlated to sheet texture.

Jan 1, 1965

By Katherine Harding

Basic concepts of matrix algebra and manipulations of matrices are presented in such a way that little competence in mathematics is required. Examples are always included to illustrate concepts and techniques. The paper is divided into six sections. The first four sections are devoted to some of the more basic concepts of matrix algebra, whereas the last two sections are concerned with specific applications.

Jan 1, 1967

By F. D. Everett

The exploration work on a seleniferous tuff deposit near Lysite, Wyo., was confined chiefly to an area of approximately 1 square mile selected on the basis of prior examination and sampling work by the Bureau of Mines. This area was superficially explored by digging and sampling over 2,000 feet of trenches and 15 test pits. The surface sampling indicated that the deposit might contain a multimillion-ton reserve of easy-to-mine volcanic tuff assaying more than 0.01 percent Se. Later, 11 holes, ranging in depth from 57 to 135 feet and totaling 929.4 feet, were drilled under contract using a dry rotary drill. Samples for assay were cut at 5-foot intervals or at noticeable physical changes in the formation being drilled. Of the 206 samples assayed from the drilling, only 8 contained more than 0.005 percent selenium, and 2 of these assayed as high as 0.012 percent Se. Chemical analyses of samples obtained from six holes drilled by the Nugget Coal & Timber Co. to the south of the area explored by the Bureau of Mines showed that no selenium-bearing formations were encountered in that work. Two of 72 samples taken from 42 validation pits dug by claim holders contained more than 0.005 percent selenium. The exploratory work established that the selenium mineralization is erratically distributed in small irregular bodies and is not confined to any one tuff bed. Because of the lack of correlation between the infrequent showing of low-grade tuff, neither the extent nor grade of the reserves could be calculated.

Jan 1, 1957

By W. A. McKinney

A sample of oxidized copper ore from a large deposit located in Pinal County, Ariz., about 50 miles northeast of Tucson, was treated by the Federal Bureau of Mines in a small-scale continuous pilot plant by a procedure which comprised acid curing complemented by water leaching and countercurrent decantation washing in a series of drag classifiers. A feed was prepared by pugging minus 1/4-in, ore with concentrated sulfuric acid and about 10 pct, of eater, followed by curing in batches for about 24 hr. The cured ore was fed continuously to a leach drum, where it was mixed with advance solution from the countercurrent washing system to dissolve the sulfated copper. The pulp was thickened and washed in four Esperanza-type classifiers, using a flocculating agent to obtain rapid settling and thickening. The leached ore pulps thickened satisfactorily in the drag classifiers when about 0.8 lb. of a polyacrylamide flocculant per ton of dry feed was used. Clear overflow liquors were obtained, and classifier rake products containing about 60 pct. solids were produced, As much as 90 lb./hr. of ore was treated in the plant, with a recovery of 60 pct. of the total copper or 80 pct, of the acid-soluble copper when 2 tons of water per ton of feed was used in washing. The acid consumption was 4.3 lb./lb. of copper recovered. On the basis of the maximum feed rate employed and the effective pulp-settling area of the classifiers, a total of 1 sq. ft. of pool area was required per ton of dry feed per day for the thickening and washing operations. The washing efficiency in the test was 95 pct.

Jan 1, 1960

By D. W. Mitchell

This Bureau of Mines report summarizes experience and past research on methods for sealing abandoned areas of a coal mine and areas from which the pillars have been wholly or partially extracted. The Federal Coal Mine Health and Safety Act of 1969 requires that such areas be ventilated or sealed with explosion-proof bulkheads, but the present study indicates that bulkheads alone cannot isolate areas in a coal mine in which methane and other dangerous gases have accumulated. Gas-air exchanges between sealed and open areas must be controlled.

Jan 1, 1971

By Wallace W. Roepke

Research on coal cutting at the Bureau of Mines Twin Cities Research Center (TCRC) has evolved from a purely mechanical approach, specifically to reduce dust or frictional methane ignitions, into an understanding of the complexity of the cutting system relationships. Achieving an understanding of these relationships requires a wide variety of testing techniques and equipment. Laboratory facilities and the associated equipment exist for shallow to deep cutting in both coal and coal-inclusive rock with any desired bit type. Research efforts with this equipment are providing insight for significant advances to help solve the problems of pneumoconiosis and frictional ignition. This effort will ultimately affect both respirable dust and methane ignitions at the face through better bit design and will increase the salable percent of run-of-mine (ROM) coal processed. It will also affect the design of rotary-drum cutting continuous mining machines (CMM) and longwall machines. This report describes the main features of the coal cutting research facilities at TCRC.

Jan 1, 1983

By T. F. Mitchell, Walter J. Long

"SUMMARYThis report is one of a series giving results of laboratory and pilot-plant investigations of the concentration of western manganese ores begun in December 1940. Data given summarize results of laboratory investigation of three samples of complex oxide manganese ores from the Madeline property, Lake View, and Victory claims, Clallam County (Olympic Peninsula), Wash. The samples represented an extremely intimate and complex association of manga¬nese oxide minerals with silica and iron.Owing to the complex nature of the ores, no effective concentration by ore-dressing methods was possible. No high-grade manganese concentrates were produced and the highest recovery at minimum accountable grade was only 55 percent on one of the ores tested.Since the Clallem County ores did not respond to ore-dressing methods, leaching processes were investigated, results of which are to be published in a separate report.INTRODUCTIONOre-beneficiation tests were conducted on three samples of manganese oxide ere from the Madeline, Lakeview, and Victory claims, Clallam County, Wash. The ores are extremely complex because of the unusually small size of manganese mineral particles, their mode of occurrence, and relationship to the gangue. None of the three ores was amenable to the production of high-grade manganese products by ore-dressing methods."

Dec 1, 1945

By K. O. Bennington

The thermodynamic properties of synthetic acmite, NaFe3+Si206, were determined by the Bureau of Mines. The enthalpy of formation was determined by hydrofluoric acid solution calorimetry. The values of the standard enthalpy of formation at 298.15 K, ?Hf°298.15, from the elements and from the oxides, ?H°298.15, are ?Hf°298.15 = -615.87 ±0.71 kcal/mole, ?H°298.15 (from oxides) = -32.08 ±0.53 kcal/mole. Various experimental data were combined with other data from the literature to calculate all the related thermodynamic properties in the range of 298 to 1,263 K. The standard Gibbs energy of formation is ?Gf°298.15 = -575.8 kcal/mole.

Jan 1, 1981

By Townsend. James W.

"INTRODUCTION As a byproduct of its mineral investigation program, the Bureau of Mines has developed a number of operating devices and techniques worthy of note. This paper, prepared under the direct supervision of Paul T. Allsman, chief, Salt Lake City Division, Branch, and under the general supervision of Lowell B. Moon, chief, Mining Branch, reports upon one such device. A simple device has been developed for measuring angles of deviation from the horizontal as recorded on a glass tube by acid etching. The device has facilities, also, for measuring the angle between the long axis of the ellipse and the north-south reference points established by a Maas compass or from an established axial lamina, on the tube, which was ori¬ented to a specific direction in the hole by rod alinement.The device was found accurate within half a degree on repeated orientations of the same tube. However, the degree of accuracy is dependent on the accuracy of personal manipulation in orienting the tube to the correct plane."

May 1, 1947

Although alternating-current (a.-c.) power systems and equipment have been used in coal mining for many years, most mines in the United States are powered mainly by direct current (d.-c.). There are several logical reasons for this, but the use of d.-c, equipment is, in most instances, a direct outgrowth of the original practice of using such power for haulage systems. For traction equipment such as the electric trolley locomotive the d.-c. motor has ideal operating characteristics, and thus it has been widely used for haulage locomotive service. The first efforts at electrification of coal mines started with the haulage system and from there branched out to include the many types of electrically powered mining machinery used in the industry today.

Jan 1, 1960

By W. R. Crane

Subsidence and ground movement are phenomena common to and attendant upon practically all large-scale mining operations, and under certain conditions may occur in all workings, large and small. The interpretation of the cause of failure in rock masses involves a study of the nature of plants of weakness common to all rocks. The dominating planes of weakness can readily be determined by observation in any given locality, and in order of importance in the study of subsidence are (1) faulting planes, (2) bedding planes, (3) joint planes, and (4) other prominent planes of weakness such as thrust and shear planes and contacts. This report has mainly to do with the third item, joint planes, and is a preliminary statement which t to be followed by a more complete report in bulletin form.

Jan 1, 1931

By R. R. Wells, W. W. Agey

"INTRODUCTION Oxide manganese ore from the Sheep Mountain property was of intermediate grade (23.0 percent manganese) and contained silica as the major impurity. The deposit from which the ore was taken is known as the Sheep Mountain manganese property and is 8 miles west of Durkee, Oreg. Test work was done in the metallurgical laboratories of the Bureau of Mines at Salt Lake City, Utah, on representative samples cut from a 290-pound shipment of crushed ore submitted by the Oregon State Department of Geology and Mineral Industries and reported to be typical of the Sheep Mountain deposit.ACKNOWLEDGMENTSThe authors wish to acknowledge the assistance of R. S. Doan, former assistant director of the Bureau of Mines, under whose supervision the manganese program was initiated in 1940, and, the valuable suggestions made to them by S. R. Zimmerley, now chief, Salt Lake City Division, Metallurgical Branch. Acknowledgment also is made to H. G. Poole and C. H. Schack for their suggestions and contributions to the organization and prosecution of the work of the Ore Dressing Section. Microscopic work on the ores and many ore-dressing products was done by L. G. Evans -and the late. B. E. Head. Our appreciation is extended also to H. E. Peterson, chief chemist, and members of the analytical staff for the many analyses made of the ores and ore-dressing products."

Nov 1, 1947

By Albert E. Long

Since December 10, 1945, the Mount Weather Branch, Mining Division, Bureau of Mines, has been maintaining detailed performance and cost records on the diamond coring bits used throughout the United States by the Bureau of Mince. Figure 1 is a copy of a typical master record sheet showing the scope and type of information recorded for each bit. It is the intention of the Bureau of Mines to issue analytical reports covering the effects of diamond size and quality on the cost of core drilling in different rocks as the information on a significant number of bits used in any one type of rock is accumulated. This report is the first of such a proposed series and is based on the diamond loss and bit costs incurred in the use of 539 AX bits in coring operations on 10 different projects involving 6,097 feet of drilling in gneiss. The 10 projects were located in New York, Pennsylvania, and New Jersey (fig. 2). As a result of the information accumulated on the use of diamond-coring bits in drilling in gneiss, it has been found that the type of bit, the matrix, the percent of core recovered, and the size and quality of diamonds used have a definite effect on the cost of bits per foot drilled.

Jan 1, 1950

By Leonard F. Heising

At the Groveland mine iron ore is mined by open-pit methods and concentrated by means of spirals and flotation. A brief history of the mine and its early development is given. The ore deposit is described, with emphasis on those physical characteristics that affect the choice of mining and milling methods. Development and mining, which include breaking ground, loading, transportation, engineering, and operating control, are explained, and the milling method is described Mining and milling costs are given in percent of total cost.

Jan 1, 1963

By Jacqueline A. McClaskey

The U.S. Bureau of Mines Information and Analysis Directorate collects worldwide data on virtually every commercially important non fuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The Bureau's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the U.S. Bureau of Mines survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1993

By W. J. Fene

Ventilation is undoubtedly the greatest single safety factor in the operation of a coal mine. Any condition or occurrence that interrupts the ventilating current or changes its normal course through the mine workings is a distinct hazard and should be considered as such by every coal-mine owner, operator, and worker. The hazard, of course, is much greater in a mine that is emitting gas, as an explosive mixture can accumulate in a very short period if the ventilating current is interrupted. It is common to find one or more entries producing 600 cubic feet or more of methane per hour. If the ventilating current were short-circuited from these entries for 15 minutes, there would be an accumulation of 150 cubic feet of methane, which, when mixed with enough air to dilute it to the lowest explosive point, would make about 3,000 cubic feet of explosive mixture; this gas could be ignited in almost any normally operated mine by a cutting machine or other electrical equipment. The ignition of this quantity of an explosive gas-air mixture can readily cause an explosion of coal dust that would completely wreck the underground workings and possibly some of the surface structures. In fact, the ignition of one-tenth of the above quantity of an explosive mixture of gas and air might readily start an explosion that would, extend through every part of a large mine. The possibility of occurrence of interruptions to the ventilating current has received comparatively little consideration from mine owners, operators, and workers in many parts of the United States. Such a possibility should be considered in connection with every mine that gives off explosive gas, and steps should be taken to prevent it.

Jan 1, 1943

By A. C. Johnson

This paper is one of a series being prepared by the Bureau of Mines on exploration, development, mining methods and costs at various mines in the United States. It describes such methods at the Lincoln tungsten mine of the Wah Chang Mining Corp., Lincoln County, Nev. The purpose of these reports is to promote development and conservation of our mineral resources by disseminating technologic information on mining methods, practices and costs. The Lincoln mine in Lincoln County, Nev., in the southeastern part of the [tate], was acquired by the Wah Chang Mining Corp., in April 1951. Mining methods and costs are of special interest at this property because of the low costs and good production record achieved through a well planned program of exploration, development, and exploitation. Operations were discontinued in July 1957 after the Federal Government suspended the tungsten purchase program.

Jan 1, 1959