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By K. K. Kershner

The purpose of this investigation was to develop methods on a laboratory scale for recovering tin from metallurgical slime, Tin chlorides were volatilized using mixtures of hydrogen chloride and reducing gases, such as hydrogen, carbon monoxide, hydrogen sulfide, ethane, propane, and butane. Optimum conditions were found to be n mixture of 3:1 of hydrogen and hydrogen chloride at 475° C. Over 95 percent of the tin was volatilized as chlorides. Low temperatures and relatively rapid rates of reaction are distinct advantages of the chloride volatilization process. Research is being continued with various slimes and will be extended to tin ores, where the method offers interesting economic possibilities in comparison with current tin-smelting practice.

Jan 1, 1957

By John I. Kasteler

The Rambler mine is in the Douglas mining district, Albany County, Wyo. (fig. 1). The property was first operated about 1870 for gold found in the outcrop of a leached ore body. Copper and metals of the platinum group were discovered, in 1900, or soon thereafter, and intermittent mining was done until 1918, when a fire destroyed the surface plant, and the underground workings caved. The mine has since been idle. The Bureau of Mines conducted a development project on the property from October 1942 to October 1943, with a recess period between November 1942 and August 1943. Ten diamond drill holes, totaling 1,859 linear feet, were drilled on the property (fig. 2). The mine dump was sampled after preparation with a bulldozer. Assay determination and spectrographic analyses disclosed small quantities of copper and metals of the platinum group in the samples. Determinations were made on 11 samples from the diamond drill holes and 23 samples from the mine dump. The assay results and spectrographic analyses are given in tables 1 and 2. The logs of the diamond drill holes are given in an appendix to this report.

Jan 1, 1949

By Robert W. Gordon

This report describes the results and conclusions of the further development of a lightweight probe drill for use in anthracite mines. Improvements to the drill previously developed under Contract H0282044 were made and tested at an Eastern Pennsylvania mine. These improvements were: 1. Better hole cleaning due to the development of an air-water mist flushing system. 2. The application of roof drill bits to allow drilling through rock seams and lenses. 3. The development of a quick coupling drill system which reduced total steel change time. 4. Adaptation of a swivel to the drill anchoring system which greatly reduced set-up time between holes. With these improvements the probe drill demonstrated its ability to drill the required 11 holes in one shift. It also gained miner acceptance as a viable underground working tool. The probe drill proved to meet all of the design requirements of portability, low weight drilling controllability, structural integrity and reliability. In addition to its ability to drill the required probe pattern, the probe drill has the capability of drilling long holes. By drilling several holes over 80 feet deep the probe drill has demonstrated a potential for use in robbing pillars and for methane drainage.

Jan 1, 1981

By W. C. Phalen

"Tho the term “magnesite” is generally applied to the iron-bearing carbonate of magnesium, such as is found in Austria and Hungary, by some Austrian magnesite is referred to as bruennerite. The mineral bruennerite has become of commercial importance only in Austria. The important deposits are found in Styria, lower Austria and northern Hungary. It is of interest to know that the world's largest deposit of spathic iron ores or iron carbonate (FeCO3), occurs at Eisenerz, Styria, while the world's largest deposit of spathic bruennerite is found at Veitsch in the same province.The Styrian and lower Austrian deposits are located much nearer the Adriatic sea than are the deposits of northern Hungary; and it is from the former that most of the exported magnesite has come. They are located south-west of Vienna, and extend west from Semmering thru the Murz Valley to Tyrol. The chief deposits reckoning from east to west are those of Semmering, Veitsch, Breitenau, Trieben, Radenthein, and Dienten.The largest and most important deposit is that at Veitsch located near Mitterdorf, on the South Austrian railroad in the Murz Valley, Styria. Here the magnesite, which occurs in the form of a lens is quarried on the slope of a hill in a series of terraces about 50 feet apart. The entire work extends thru a vertical distance of 500 feet. The huge magnesite lens is nearly 4 of a mile long and over 1,000 feet in width, and probably extends to a considerable depth.The formation containing the magnesite extends eastward beyond Vienna into Northern Hungary where magnesite is quarried beyond Jolsva and Nyustya in the Gomor district. In spite of the remote location of these deposits as compared with those in Styria, magnesite was shipped from them before the war a distance of 360 miles to the port of Fiume for overseas shipments to other parts of Europe and to America.The average analysis showing the composition of the Austria-Hungary mineral is as follows:The magnesite occurs as lenticular masses in a belt of Carboniferous rocks consisting mainly of metamorphosed Shales, sandstones, conglomerates,,and limestone, It is grayish in color when fresh, and contains sufficient ferrous carbonate to blacken it when calcined. It turns brown owing to the oxide ion of the ferrous carbonate when exposed to the air. The quantity of carbonate of iron is ariable and different analyses show that it ranges up to 13 or 14%For the most part, only the sintered article has been imported into The United States. This material has achieved an enviable reputation for its uniformity both as to chemical and physical characteristics. The homogeneity of the sintered Austrian magnesite is doubtless due in part to the averaging effect of the different operations, such as crushing, dressing, sintering, And mixing, n effect which is not obtainable in mere hand samples.There is comparatively little variability in the sintered magnesite as marketed, and five analyses of this sintered magnesite as quoted by Cornu* are gas follows:"

Aug 1, 1919

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 Chas. G. Maier

The bright annealing of copper is an industrial practice of considerable importance. In connection with this process, equilibrium concentrations of carbon monoxide and dioxide, which may exist in contact with copper and cuprous oxide at elevated temperatures, are of interest. Data obtained at the Pacific Experiment Station of the U. S. Bureau of Mines enable estimates of these equilibrium concentrations to be made in two independent ways. Although the publication of final data on one method can not take place until certain further experimental work is accomplished, repeated requests which the Bureau of Minus has had for data relative to the annealing and deoxidation of copper justify the present preliminary report. This paper deals with the calculation of gas concentrations in the reduction of cuprous oxide, using more scientific data which will be published later, and refers especially to those conditions of temperature and concentration of practical implication, and from which critical limits ensue.

Jan 1, 1929

By Richard A. Winters

The 31,880-acre Battle Creek Wilderness Study Area (WSA) was evaluated for mineral resources by the U.S. Bureau of Mines in 1984. No mining district is in the area, nor were any mines or claims recorded or found. Oil and gas leases, or lease applications, covered about half the area in early 1984. No known exploration has occurred. The entire WSA is covered with thick volcanic flows. Faults in these volcanic rocks may have provided conduits for mineralizing solutions emanating from the basement rocks; however, no evidence of mineral deposits was detected from rock samples collected along the faults. Reconnaissance samples from sand and gravel deposits yielded gold at less than $0.02/yd3. The source of the gold is assumed to be intrusive rocks or the Challis Volcanics about 20 miles north of the study area near the headwaters of Battle Creek. No economic concentrations of minerals were found in the WSA. INTRODUCTION Mineral surveys of designated wilderness study areas (WSAs) 1/ are conducted by the U.S. Bureau of Mines (USBM) and the U.S. Geological Survey (USGS) at the request of the U.S. Bureau of Land Management (BLM). The USBM researches the mining and mineral exploration history and evaluates mines, prospects, and mineralized areas within or adjacent to WSAs. The USGS studies WSAs by regional geochemical and geophysical surveys and geological mapping. The USBM and the USGS investigations are summarized in a joint report used to help determine the suitability of WSAs for inclusion into the National Wilderness Preservation System. Although the immediate goal of this USBM study is to provide data for the President, Congress, BLM, and the general public for land-use decisions, the long-term objective is to help insure that the Nation has an adequate and dependable supply of minerals at reasonable cost.

Jan 1, 1985

By A. S. Prokopovitsh

A spectrophotometric method for the determination of small amounts of copper in tungsten metal powder using the principle of solvent extraction has been developed by the Federal Bureau of Mines. The metallic sample is dissolved in hydrogen peroxide, tartaric acid added, the pH adjusted, and the excess peroxide destroyed by boiling. Copper is reduced to the cuprous state, and the reagent neocuproine (2,9-dimethy1-1,10-phenanthroline) is added to form a colored complex with the copper. This colored complex is then extracted into chloroform and the absorbance of the separated chloroform layer measured on a spectrophotometer. Copper contents as low as 1 p.p.m. (parts per million) can be determined. The method is limited to finely divided tungsten powder. The interest of the Bureau of Mines in developing more sensitive methods for the determination of trace impurities in high-purity tungsten prompted an investigation of the possibility of using solvent extraction-colorimetric methods. The organic reagents now commercially available make possible many extremely sensitive colorimetric methods for the determination of metallic ions. Extraction of the colored complex into a small volume of organic phase can be used to further increase sensitivity (4) .4/ This general approach has the added advantage that no special equipment beyond that normally found in an analytical laboratory is required.

Jan 1, 1961

By J. G. Stuart, A. W. Cipkins, R. H. Thompson

Preliminary safe distances for blasting wiring from typical electromagnetic sources are presented. The distances are for underground coal mines and electromagnetic sources in the frequency range below 10 MHz. The distances are based on measurements performed at 3 locations in each of 3 coal mines. The measurement apparatus, measurement procedure, measurement results and the rationale used in the calculation of the safe distances are all described. The safe distances presented are dependent on the measurement results and their interpretation. More measurements are clearly necessary to establish the validity of the suggested distances.

Jan 1, 1985

By J. M. Singer

The objective of this investigation was to determine minimum air velocities and entrainment rates for coal and rock dust dispersion in wind tunnel experiments under conditions that simulate dispersion from surfaces in coal mines where airflows are induced by weak gas explosions. Dust deposits were bed-or ridge-shaped; particle sizes were 6 to 80 microns (cohesive deposits) or 100 to 150 microns (free-flowing deposits); and wind tunnels were 7.62 cm wide by 5.08 cm high by 300 cm long, and 2.4 m wide by 1.5 m high by 215 m long. The investigation showed that minimum air velocities (directed at mid-height) of separate, layered, or mixed piles of coal dust and rock dust were within the range 5 to 30 m/sec, independent of size of wind tunnel. This finding considerably facilitates scaling of data to mine-size passageways. Free-flowing deposits dispersed relatively slowly by single-particle detachment; cohesive dusts dispersed faster by the breaking and lifting of large clumps along weak failure flames; particle dispersion occurred in flight. Layered or mixed deposits of coal and rock dust did not disperse selectively. Semiempirical expressions were derived relating minimum air velocities and dispersion rates to dust-pile geometry, cohesion, porosity, and bulk density.

Jan 1, 1972

By S. Ralph Austin

This Bureau of Mines investigation determined the effects of so-called annealing at high temperatures on radon-222 emanation from domestic uranium ores. Concurrently, a method was developed for closely estimating the emanation coefficients of hot samples from measurements of their gamma activity after cooling. Emanation coefficients of 102 samples from 14 domestic areas of past, present, and possible future uranium production were investigated using modifications of the closed-can, gamma-only assay method at and after cooling from 100° to 1,000° C. True annealing probably does not occur below 500° C. In limited investigations at 500° C and above, effects of annealing are masked by the effects of other parameters. Emanation is commonly less at one or more of the steps investigated in the 100° to 500° C range than before heating. This decrease is tentatively attributed to water loss at temperatures dependent upon the minerals present. The average sample emanates least at 300° C; emanation increases with higher temperatures to at least 900° C. Emanation decreases sharply on cooling, but it is partially restored by prolonged exposure to the atmosphere at room temperature. Higher than average emanation of coffinite ores at 500° C and above may be related to destruction of the coffinite crystal structure.

Jan 1, 1979

Lower workers' dust exposures during bag stacking while ergonomically improving the bag stacking process. Approach Install a new pallet loading dust control system which uses a push-pull ventilation technique along with a hydraulic lift table to control the pallet loading height throughout the entire loading cycle. How It Works A low-volume, high-velocity blower system operating at approximately at 120 cfm blows a stream of air over the top layer of bags on the pallet. The blower system is composed of two 3-inch air jets (approximately 1,200-ft/min velocity) directed toward an exhaust system on the opposite side of the pallet. As these air jets travel across the pallet, they en-train dust generated during bag stacking. The dust laden air is then captured by the exhaust ventilation system which draws approximately 2,500 cfm through an exhaust hood on the opposite side of the pallet.

Jan 1, 1989

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 Russell R. Trengove

The Bureau of Mines developed by core drilling the Cove Meadow copper property, also known as the Patterson property, from May 6, 1949, to August 6, 1949. It is in the Cove Meadow mining district, northwestern Humboldt County, Nev., 102 miles northwest of Winnemucca. The purpose of the work was to determine possible reserves in a mineralized shear zone in andesite that has been partly explored by several surface cuts and two shallow underground workings. Production from this zone to August 1, 1,949, was 98 tons of hand-sorted copper ore assaying 5.1 percent. The development work performed by the Bureau of Mines comprised a study of the geology, mapping the area, sampling the outcrops, and exploring by diamond drilling the shear zone adjacent to the fault. Seven holes were drilled for a total of 1,246 feet. Mineral reserves indicated by the project are confined to a length of 500 feet along the strike.

Jan 1, 1950

By H. S. Chiang, Zhao. Y. F., G. C. Sun, S. S. Peng

"Chiang; H. S. West Virginia UniversityPeng, S. S. West Virginia UniversitySun, G. C. West Virginia UniversityZhao, Y. F.West Virginia UniversityDust sampling was performed in two longwall faces working in two separate seams. Instantaneous dust samples were measured by RAH's. for various locations In the longwall faces. Preliminary analysis of the data shows that in addition to the shearer's haulage speed, there are four major factors that influence the airborne dust distribution in longwall face areas: locations with respect to the position of the shearer's cutting, hardness of the materials, characteristics of water spray, and roof conditions. This paper presents the effects of those four parameters in detail.INTRODUCTIONA research project was initiated in September 1983 to measure and construct .a dust distribution map for the longwall face. During the first year, airborne dust samplings were performed in two longwall panels located in northern and southern West Virginia and working in the Pittsburgh and Eagle Seams, respectively. The physical parameters and equipment employed for both panels are 1 isled in Table 1. Figure 1 shows the detailed characteristics of the coal seams. Notice in both panels floor cutting was involved either to gain sufficient mining height or to reduce the adverse effects associated with a soft floor.The purpose of the research is to define the dust distribution at any instance in the longwall face area so that proper working positions can be determined and/or effective dust control techniques can be developed.This paper presents the partial results obtained during the first year."

Jan 1, 1988

By J. Mutmansky, C. Lee

"The size distribution of coal mine dust is one of its most important characteristics because the particle size is known to govern the region of deposition of dust within the human respiratory tract. In addition, dust characteristics, particle settling rate, transportability of the dust and the efficiency of dust control measures are all affected by the particle size. As a result, particle size distribution of the airborne dust in a coal mine is a fundamental property that impacts on the health of underground workers.This paper deals with some basic findings on the size distribution of cool mine dust based upon the results of data collection in six underground coal mines using continuous miners. All airborne dust sampling was performed on development sections using eight stage cascade impactors and permissible 2. O l / min pumps. Samplers locations were fixed in the sections with respect to the continuous miner and roofbolter or with respect to the intake and return airways • Sampling times varied from 45 minutes to 6 hours , depending upon the dust concentration. The first topic of analysis was the test to determine whether the commonly used lognonnal distribution is valid when applied to airborne coal mine dust. Secondly, the conventional method of representing the· distribution using two parameters, the geometric mean and the geometric standard deviation, is questioned. Since almost all size data were found to show some degree of bimodality, the two parameter lognonnal distribution may not represent the total airborne coal mine dust size , quite adequately. Bimodal lognonnal distribution was tested to be a good approximation in the case with two modes in the size distribution.The final topic discussed in this paper is the 'locational variation of the airborne dust size distributions within the continuous mining section. The size distributions varied considerably at the different sampling locations with the continuous miner and roofbolter producing the coarser distributions. Fine size modes in the range of 2 to 4µ m including mostly respirable dust particles were present in almost all samples • Second dust generating sources such as the shuttle car movement were found to be major causes of high respirable dust concentrations in some cases ."

Jan 1, 1988

By N. S. Dalal, X. Shi

"With a view of elucidating the role of glutathione (GSH) in the biochemical pathways of the chromate-exposure related carcinogenesis, we carried out electron spin resonance (ESR) spectroscopic investigations of the chromate-GSH redox reactions. The ESR measurements, employing spin-traps, provide evidence for the involvement of the glutathione (GS•) radical, as well as an isolable Cr(V)-glutathione intermediate. These results indicater a new mechanism for the reduction of chromate by GSH in cellular environment and help understand the (unexpected increase in Cr(VI)-induced DNA strand breaks at elevated GSH levels.We report here indirect electron spin resonance (EGR evidence for the involvement of the glutathionyl (GS) radical and direct evidence for a Cr(V) intermediate in the reactions of glutathione ¬(GSH) with chromate for the first time.. This work was undertaken to clarify the biochemical pathway of the reduction of chromate by GSH, since this reduction process is thought to be a critical step in the pathogenesis of the chromate-exposure related carcinogenesis. This follows from the literature reports which show that (a) Cr(VI)compounds have been proven to be carcinogens in laboratory animals as well as in human studies2-4, (b) Cr(VI) and not Cr(III) compounds are mutagenic 5-7, (c) Cr(VI) and not Cr(III) compounds can penetrate cell membranes 8.9 (d) the final state of Cr(VI) in cellular reductions is Cr(III)', (e) by itself chromate (or Cr(VI)) cannot be directly mutagenic since Cr(VI) is known not to interact with isolated DNA under physiological conditions 10, suggesting the significance of Cr(VI).reduction processes. One of the major reductants in cellular environments is thought to be the GSH, both outside and inside the ce11s 11-13. Other evidence for the role of GSH in the chromate toxicity is seen from recent studies showing that exposure of hamster cells to non-toxic levels of added selenite increases the levels' of GSH as well as the Cr(VI)-induced DNA strand beaks 14, and thatsuch DNA strand breaks in hepatocytes also change in direct proportion to their GSH content 15,16. These observations wereinterpreted as implying that the reduction of chromate by GSH, to some reactive intermediate is an important step in the chromatecarcinogenicity 15,16. The following reaction steps were,suggested 15, 16"

Jan 1, 1988

By John A. Johnson

Tests ere conducted at the Mount Weather testing adit of the 57 Bureau of Mines on the effectiveness of spraying water along the outside of the drill steel as compared with standard wet-drilling practice. The spray equipment used in the tests was designed primarily for the control, in quarries, of dust from dry drilling with solid type drill steel. Equipment Spray equipment is made in sizes to fit different drill steel but is alike in design, the only difference being in the diameter of the ring and the number of spray holes. The device is mace of cast steel and has a coating of Stellite on the inside edge that comes in contact with the drill steel. It looks like a garden spray, except that the spray holes point in only one direction.

Jan 1, 1939

By Frank E. Cash

Since ventilation adequate in quantity as well as quality is of paramount importance to the health and safety of men working underground in coal mines, mining officials, employees, and State inspection departments should give it the closest possible attention. MINING LAW OF ALABAMA The law governing, and regulating the operation of coal mines in Alabama was enacted in 1911 and amended or revised in 1923, 1925, 1930, and 1935. The original law and subsequent revisions were progressive steps in safeguarding the health and safety of underground employees.

Jan 1, 1939

By John A. Johnson

[Tests were conducted at the Mount Weather testing adit of the Bureau of Mines4/ on the effectiveness of spraying water along the outside of the drill steel as compared with standard wet-drilling practice. The spray equipment used in the tests was designed primarily for the control, in quarries, of dust from dry drilling with solid type drill steel. EQUIPMENT Spray equipment is made in sizes to fit different drill steel but is alike in design, the only difference being in the diameter of the ring and the number of spray holes. The device is made of cast steel and has a coating of Stellite on the inside edge that comes in contact with the drill steel. It looks like a garden spray, except that the spray holes point in only one direction.]

Jan 1, 1939