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By T. J. Ballard

The Ore Knob mine, in Ashe County, N.C., was one of the largest producers of copper in the eastern states during the 1870's. The ore occurs in a fissure vein, which strikes N. 64° E. and dips nearly vertical. The country rock is granite gneiss. Drilling indicated that the vein structure is approximately 200 feet wide and 1,500 feet long. The vein material shows evidence of replacement of the original gneiss by sulfides. Solution cavities in the vein were noted in some places. The ore minerals and pyrrhotite, chalcopyrite, pyrite, and minor quantities of sphalerite. The gangue contains biotite, magnetite, albite, calcite, and many silicate minerals.

Jan 1, 1948

By Robert L. Chufo

The paper, "An Electromagnetic Roof and Rib Thickness Sensor" presented at The 12th WVU International Mining Electrotechnology Conference in 1992, presented the results of roof coal thickness measurements in underground mines and rib coal thickness measurements in highwall mines. The microwave sensor described uses a unique spatial modulation scheme created by antenna motion, along with frequency domain signal processing, to solve the problem of media, target, and antenna dispersion. This paper further describes the advantages of the unique frequency domain signal processing technology chosen by the U.S. Bureau of Mines in extending previously reported one-dimensional thickness measurement technology to the generation of a full three-dimensional underground image of the underground environment. The electromagnetic signature of a media, whether it is coal or other geological material, is its permeability and permittivity and the effect on the velocity and amplitude of an electromagnetic wave as it passes through. High-quality imaging cannot occur without the identification of, and correction for, the permittivity and permeability of each layer of a multilayer geological deposit. Clutter, or any signal that can interfere with target discrimination, usually comes from objects in the field of view for which there is no design control. These are nuisance targets with possibly very high contrasts compared to the real target. The only proven tool to reduce clutter is to increase spatial, spectral, and polarization diversity. This paper will describe some techniques being used by the U.S. Bureau of Mines to increase the information content of both single-dimensional and three-dimensional imaging systems through the identification of media distortion mechanisms made possible by the use of spatial/spectral sensor technology. These techniques will permit high quality imaging in an environment where the data is corrupted by dispersion and clutter.

By R. E. Heithecker, Van A. Mills

"Crude oils are capable of dissolving quantities of gas under pressure. This fact has been known for some time, but questions have arisen as to the effects of gas in solution upon the characteristics of the oil. Previous investigations4 show that gas in solution in an oil affects the viscosity and surface tension of the oil, but the effects on the volume and A. P. I. gravity of the oil have not been known. The results given in this report show that there is a decided change both in volume and in the A. P. I. gravity of the oil due to the solution of the gas in the oil under pressure. As gas is dissolved, the volume of the oil and the A. P. I. gravity increase. The converse of this phenomenon is also true: if the gas is released from a saturated oil, there is a shrinkage in volume and a decrease in A.P.I. gravity due to the release of gas from solution. However, various oils show marked tendencies to retain a portion of the dissolved gas upon releasing the pressure to that of the atmosphere. This retained gas has an appreciable effect on the volume and A. P. I. gravity of the oil because the oil does not resume its initial volume or gravity while it retains dissolved gas. In a sense the oil has been ""freshened"" and will not return to its original or weathered volume until it loses some of the lighter fractions. Wiggins5 has shown that a fresh oil decreases both in volume and in gravity because of the weathering of the lighter fractions while the oil is standing in storage tanks.This paper includes data attained during the determination of volume and gravity correction factors to be applied in the oil recovery investigations of the Bureau of Mines. Three oils having a wide range in gravity were used in determining the correction factors. These oils were from the Bartlesville-Dewey field, Oklahoma, the Seminole field, Oklahoma, and the Inglewood field, California. The same gas that was used in the oil recovery experiments was used throughout this investigation. Determinations were made of the volume and A.P.I. gravity increases resulting from the gas going into solution at 200, 400, 600, 800, and 1,000 pounds pressure; also the increases in the volume and gravity of the oil due to retained gas were determined after the dissolved gas was liberated from solution by releasing the pressure to that of the atmosphere.Samples of residual and liberated gas were taken throughout the investigation in order to study the selective absorption and selective retention by the oil of the various constituents of the gas. The analyses of these gas samples showed that there was selective absorption and selective retention of the constituents of the gas. The tests on Inglewood crude gave the most pronounced example of selective absorption and selective retention of the gas.All of the tests were conducted at a constant temperature of 709F."

Oct 1, 1928

By C. W. Smith

Research was conducted to evaluate the effectiveness of a well-point dewatering system in conjunction with a french drain to intercept waste impoundment leakage while reducing the volume of waste water requiring treatment. A well-point dewatering system composed of 585 production wells was installed around the perimeter of a leaking impoundment that previously used only a french-drain system for leakage control. The placement of the well-point system was designed to intercept and remove the leakage from the groundwater before the contaminant reached the french drain. Groundwater monitoring at this site revealed that after a period of approximately 40 days the well-point dewatering system had stabilized and effectively prevented the further spread of contamination to the french drain.

Jan 1, 2010

By Kevin Ashley

Because toxicities may differ for Cr(VI) compounds of varying solubility, some countries and organizations have promulgated different occupational exposure limits (OELs) for soluble and insoluble hexavalent chromium (Cr(VI)) compounds, and analytical methods are needed to determine these species in workplace air samples. To address this need, international standard methods ASTM D6832 and ISO 16740 have been published that describe sequential extraction techniques for soluble and insoluble Cr(VI) in samples collected from occupational settings. However, no published performance data were previously available for these Cr(VI) sequential extraction procedures. In this work, the sequential extraction methods outlined in the relevant international standards were investigated. The procedures tested involved the use of either deionized water or an ammonium sulfate/ ammonium hydroxide buffer solution to target soluble Cr(VI) species. This was followed by extraction in a sodium carbonate/sodium hydroxide buffer solution to dissolve insoluble Cr(VI) compounds. Three-step sequential extraction with (1) water, (2) sulfate buffer and (3) carbonate buffer was also investigated. Sequential extractions were carried out on spiked samples of soluble, sparingly soluble and insoluble Cr(VI) compounds, and analyses were then generally carried out by using the diphenylcarbazide method. Similar experiments were performed on paint pigment samples and on airborne particulate ?lter samples collected from stainless steel welding. Potential interferences from soluble and insoluble Cr(III) compounds, as well as from Fe(II), were investigated. Interferences from Cr(III) species were generally absent, while the presence of Fe(II) resulted in low Cr(VI) recoveries. Two-step sequential extraction of spiked samples with (?rst) either water or sulfate buffer, and then carbonate buffer, yielded quantitative recoveries of soluble Cr(VI) and insoluble Cr(VI), respectively. Three-step sequential extraction gave excessively high recoveries of soluble Cr(VI), low recoveries of sparingly soluble Cr(VI), and quantitative recoveries of insoluble Cr(VI). Experiments on paint pigment samples using two-step extraction with water and carbonate buffer yielded varying percentages of relative fractions of soluble and insoluble Cr(VI). Sequential extractions of stainless steel welding fume air ?lter samples demonstrated the predominance of soluble Cr(VI) compounds in such samples. The performance data obtained in this work support the Cr(VI) sequential extraction procedures described in the international standards.

Jan 1, 2009

By H. R. Grau

NIOSH’s Pittsburgh Research Laboratory is currently involved in research to identify silica dust generation in underground metal/nonmetal mines. The ultimate goal of this research is to develop control technologies to reduce worker exposure to respirable silica dust. Commodities and job classifications with the highest silica dust exposure have been identified through analysis of the Mine Safety and Health Administration (MSHA) compliance dust sampling database. Dust surveys were conducted in an underground limestone and gold mine to investigate silica dust sources, generation levels, and controls being used. A summary of the mining operations, sampling procedures, resulting data, and suggested methods to improve the dust control will be provided.

By R. E. Lindstrom

A study of ion-exchange resin crosslinkage and eluant flow rate, resin-bed shape, and addition of separating ions to feed stock was undertaken to determine their effect on the separation efficiency of ion-exchange on bastna-site-rare-earth elements. Results show that 12-percent divinylbenzene (DVB) crosslinkage resin is detrimental to separation efficiency at flow rates over 2 to 5 ml./min./sq. cm.; whereas, separation with 4-percent DVB crosslinkage resin is relatively unaffected by flow rates between 2 and 10 m1./min./sq.cm.

Jan 1, 1959

By E. C. Lane

Although motor gasoline marketed in the United States in January of this year was, on the average, slightly more volatile than that sold in January 1925, the improvement in quality is too small to be of importance. In other words, there is no evidence that any radical change in the quality of gasoline is being made at the present time. During the past six years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States, the survey just completed being the thirteenth in the series. The cities in which samples have been collected have been chosen as representative of the more important marketing territories as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country.

Jan 1, 1926

By Floyd D. Everett

The Cougar Spar property is in southwestern Beaver County, Utah, approximately 35 miles by road northwest of Lund, a station on the mainline of the Union Pacific Railroad (fig. 1). Original fluorspar discoveries on the property were made a. short time before 1941. During 1941 lessees produced approximately 600 tons of ores averaging 40 percent CaF2. Bureau of Mines engineers examined the property in 1942 and recommended development. Work was begun in December 1942 and completed in October 1943. The area was mapped by members of the Federal Geological Survey during the project period. Development included surface trenching; drifting, and crosscutting, a short distance below the outcrop. The surface work comprised a total of 440 linear feet of bulldozer and hand trenches. A total of 550 feet of workings was driven on the 100-foot level. Samples were taken for assay from the trench exposures and from the underground workings as work progressed. Pocks in the area of the Cougar Spar property are igneous and consist mainly of fine-grained tuff and quartz monzonite porphyry. The fluorspar mineralization occurs in a northwest fault zone.

Jan 1, 1951

By Wing G. Agnew, Paul L. Russell

"INTRODUCTION During the past few years, the development of millisecond-delay electric blasting caps has made possible a more flexible control over timing the firing of individual charges in blasting, The use of these caps has proved especially productive in quarry blasting and in numerous construction operations, but their use in underground mining is developing more slowly, although in some cases, as the solution to a difficult breaking problem, they have been well-received. When used in metal-mine drifts, the general objection is that the broken rock is thrown too far. In nearly all cases, however, use of millisecond-delay caps results in better fragmentation of the rock and a lower powder consumption per ton of rock broken.Prom 1949 to 1952, several series of experiments were conducted at the Mount Weather, Va., Experimental mine in conjunction with driving a 6- by 10-toot ventilation raise. 3/4/ The raise-round experiments in this 238-foot shaft, using millisecond-delay electric blasting caps in various drill-round patterns, are the subject of this report.SUMMARY AND CONCLUSIONSAll rounds discussed in this report were drilled in the hard rock (epidosite and greenstone) of the ventilation raise at Mount Weather Experimental mine (figs. 1 and 2). The drill-round patterns varied from 28- to 32 holes and from a V-cut design to one having no cut boles at all. With the exception of the first two rounds, all blasting was done with millisecond-delay electric blasting caps. In all rounds 60-percent ammonia gelatin dynamite was used and holes were stemmed with two cartridges of sand stemming."

Apr 1, 1953

By D. E. Andrus

This paper, which describes the milling practice at the Montana mine concentrator of the Eagle-Picher Lead Co., is one of a series being prepared by the United Slates Bureau of Mines. LOCATION The Montana mine is situated on the eastern edge of the Oro Blanco mountains at an elevation of 4,300 feet. It is in the Oro Blanco mining district, Santa Cruz County, in the southern part of Arizona, about 4 miles north of the Mexican border, 30 miles northwest of Nogales and 80 miles southwest of Tucson. Amado, a station on the Southern Pacific Railroad, midway between Tucson and Nogales, and about 40 miles northeast of the mine, is the shipping point and is reached over an excellent highway.

Jan 1, 1931

By Green R. E.

The removal of silica from commercial iron oxide concentrates by dissolution with sodium hydroxide was investigated by the Bureau of Mines as a means for producing supergrade concentrates. The effects of strength of solution, temperature, and digestion time on the extraction of silica were evaluated using eight iron oxide concentrates. Silica extraction from the eight concentrates was enhanced by autoclave leaching in the temperature range of 150° to 250° C and varied from 70 to 95 pct depending on the concentrate used. Superconcentrates containing less than 2 pct Si02 and more than 69 pct Fe were made only when magnetite concentrates were leached in the autoclave. The investigation showed that it is not difficult to obtain a supergrade product if the gangue is mainly quartz.

Jan 1, 1973

By J. M. Mutmansky, S. Padmanabhan

"The subject of quartz occurrences in respirable coal mine dusts has been of increasing concern in recent years. The primary impetus for this concern has been provided by better measurement technology that has detected an increased number of mines with high quartz content in their respirable dusts. This paper presents the results of statistical analyses of quartz levels in multi-stage impactor samples from eighteen different coal mining sections located in Pennsylvania, West Virginia, Ohio, Illinois, Kentucky, Colorado and Ucah. The quartz and kaolinite determinations were then determined by combining impactor stage loadings to provide larger dust masses and applying the infrared spectrometry procedure outlined in Bureau of Mines/MSHA Method P7.The results will be presented using two categories of data collected during two separate phases of the research:(l) quartz concentration data from mines where quartz was known to be present in relatively high concentrations, and(2) quartz concentration data from mines chosen at random.The aspects of the occurrence of quartz in coal mine airborne dusts that will be reported include the size dependence of the quartz content, quartz variations with location in the mining section, and variations due to mining region. The results of the study show a strong pattern of size dependence of the quartz content in mines for which high quartz concentrations exist. A similar, though less pronounced, pattern exists in mines chosen at random. Quartz levels appear to have a varying relationship to section location and strong geographical patterns do not appear to exist in the data collected. Kaolinite content was found to be similar to that of quartz with patterns that are somewhat more consistent."

Jan 1, 1989

By A. F. Colombo, D. W. Frommer

Bench- scale tests were made to determine the applicability of flotation as a means of upgrading finished and semifinished magnetic concentrates prepared from reductively roasted iron ores . Both anionic and cationic flotation methods were used to remove siliceous gangue from the magnetic concentrates and produce upgraded products . Seven magnetic concentrates , containing from 6.7 to 13.7 percent SiO2 , were improved by the flotation treatment , yielding final concentrates containing less than 6.0 percent Si02 . Cationic flotation methods were studied on four of the seven samples ; of this group only one sample yielded better results by cationic flotation than by the anionic method .

Jan 1, 1964

By John D. Prater

Thallium is one of the rarer metals that has come into commercial importance in recent years. Although the element was first reported by Crookes in seleniferous deposits in lead chambers of a sulfuric acid plant in the Harz Mountains of Germany, it had no commercial significance until about 190O because of the high cost of extraction. Thallium occurs widely in the earth's crust but is found in such low concentrations that it is recovered only as a byproduct from processing other elements. There are no domestic ores of thallium; the entire output in this country is supplied by the American Smelting & Refining Co. as a byproduct of its cadmium operations at Globe, Colo. Thallium also is recovered from the flue dusts of sulfuric acid works in which thallium-bearing materials are used and as a byproduct of the lithopone industry. This paper describes methods for recovery of thallium from 'white arsenic" and lead Cottrell-precipitator dust of the American Smelting & Refining Co., lead smelter, Murray, Utah. Owing to an enlarged market for thallium because of increased military requirements and expanded peacetime uses, the Salt Lake Station of the Bureau of Mines surveyed the occurrence of thallium in ores, concentrates, and smelter products from all parts of the nation and found the most promising source was certain smelter products of the American Smelting & Refining Co. plant, Murray, Utah. Much of the thallium was being lost in marketed arsenic products; therefore, this investigation was undertaken to develop methods for recovering the thallium.

Jan 1, 1952

By Raja V. Ramani

The potential usefulness of reclaimed surface-mined land has received much attention recently. In an effort to develop a procedure for evaluating postmining land use potentials, specific mines in various regions of the U.S. were studied to determine the extent of current mined-land planning and to discover characteristics that are regional in nature. As part of this investigation, the Chinook Mine-West Field, located in western Indiana, has been studied. The Chinook Mine is presently operated by AMAX Coal Company and has been in continuous operation since 1928 under various ownership. The status of current reclamation and land use planning was reviewed. In addition, site planning principles were applied to the active mine area. This application included formation of a data base and development of postmining land use plan alternatives. Key factors affecting site potential realization for midwestern area mines have been identified along with suggestions for applying land use planning processes to mined-land planning.

Jan 1, 1983

By Peter Kovalchikb, Gregory Colec, Syd Peng, R. J. Matetic, Jeffrey Petersond

Mine Safety and Health Administration (MSHA) data indicates that the roof bolting machine is third among all equipment and second among equipment in underground coal mining whose operators exceed the MSHA-PEL (Mine Safety and Health Administration-Permissible Exposure Limit). In response to this, the National Institute for Occupational Safety and Health (NIOSH) has conducted a study to reduce overexposures of noise to operators of roof bolting machines. An important segment of the research is to determine, characterize and measure sound power levels radiated by a roof bolting machine during different drilling configurations. The determined sound power levels generated during the drilling cycle are of major interest because the levels represent the overall sound power generated by the machine. These sound power levels, determined from laboratory tests, can be used to accurately assess the effectiveness of proposed controls for reducing noise exposure to roof bolting machine operators. By using the sound power level results obtained from the laboratory and a commercially available acoustical modeling package, a method for predicting sound pressure levels to roof bolting machine operators for differing drilling types and parameters could be determined. This paper provides a method for predicting sound pressure levels at the operator’s position of a roof bolting machine in an underground coal mine using sound power levels determined in the laboratory. To determine validity, underground coal mine data was also collected to compare predicted and measured sound pressure levels. The results of the predicted sound pressure level data were the same as the underground measured results. This research will provide the mining industry with a valid method for predicting a roof bolting machine operator’s noise dosage underground given any type of drilling configuration or drilling method utilized from laboratory testing.

By H. J. Lechtenberg

This Bureau of Mines report investigates solvent injection as a means of increasing oil production from low-gravity oilfields; thus, wells in two California oilfields that produce from reservoirs having low-gravity oil were injected with highly aromatic solvents to increase their oil recovery. The wells were either allowed to soak or the solvent was circulated for a period of time. In some of the wells, the solvent was followed by a slug of water. The post-stimulation production rate was considerably higher than the prestimulation rate of the wells. Wells in which the solvent was not followed by water showed an immediate increase in oil production, and essentially all of the solvent was recovered. The wells in which solvent was followed by water essentially showed a delay in the increase in oil production, thus indicating a temporary water block. The results show that the production rate is usually increased by the injection of solvent, and the method may prevent early abandonment of marginal producers. Cumulative post-stimulation oil production indicates that cyclic solvent injection treatment can be an economic success.

Jan 1, 1974

By T. M. Romslo

"INTRODUCTION This report presents factual data obtained by the Bureau of Mines in the course of an investigation of the Antler mine in the Cedar Valley mining district, Mohave County, Ariz.The Antler property was first examined by Thomas L. Chapman, mining engineer, Bureau of Mines, on December 18, 1943, and January 28, 1944. In June 1945, A. H. Wadsworth, Jr., and R. L. Griggs, geologists, Federal Geo¬logical Survey, examined the Antler mine and several other mines in the district. Both Chapman and Wadsworth recommended diamond drilling of the Antler property to determine the character and extent of ore deposition.In October 1946, the surface and underground workings were surveyed by George Huseman, Mining engineer, and T. M. Romslo, project engineer. The following month Eldred. D. Wilson, geologist of the Arizona Bureau of Mines, assisted by the project engineer, mapped the geology. Subsequently trails were built to drilling sites and diamond drilling started January 16, 1947. The project was completed April 25, 1947.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes samples and takes beneficiation tests."

Mar 1, 1948

By K. E. Stanfield

Asphalts from. Wyoming "black oils" are being studied at the Petroleum Experiment Station of the Bureau of Mines at Laramie, Wyo., in cooperation with the University of Wyoming. These black oils are characterized by their high-asphalt, high-sulphur, and low-gasoline content and are difficult to refine by present methods into high-octane motor fuels, burning oils, and lubricants. Accordingly, their principal use, at present, is for the manufacture of road oil and asphalt. The present production of black oil could be increased to meet a greater demand. During 1937 the daily production of these crude oils in Wyoming was slightly over 13,000 barrels, while the estimated potential production from existing wells was 56,000 barrels.

Jan 1, 1939