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By G. V. Sullivan

The Bureau of Mines conducted preliminary beneficiation studies of a gold-bearing graphitic schist from Blue Hill, Tallapoosa County, Ala. The average analysis of the material was 0.08 oz/ton gold. Tabling of minus 35-mesh material recovered 83 to 94 percent of the gold at grades of 6.925 to 2.165 oz/ton, respectively. A combination of jigging and tabling resulted in a concentrate assaying 24.3 oz/ton gold and contained 87 percent of the total gold. Treatment of the material by jigging, tabling, and amalgamation recovered 86.5 percent of the gold.

Jan 1, 1969

By V. M. Benson

A simplified, routine method for determining lithium in lithium-bearing rock is presented. The sample is decomposed by repeated treatments with nitric, hydrofluoric, and perchloric acids. Since this procedure does not appreciably dissolve beryl, interference by beryllium (the principal interfering cation) is minimized for most samples. The salts are brought into solution with water and enough citric acid-ammonium citrate buffer is added to make the final volumetric dilution 0.20 M with respect to citrate. The addition of citrate greatly reduces anion interference in the hydrogen-oxygen flame, slightly increases the intensity of the lithium 671 millimicron emission line, and reduces the effect of most of the interfering cations to the extent that analytical separations are not necessary. The accuracy of results of single determinations of lithium in a pegmatite containing spodumene, lithium-bearing mica, and beryl are approximately equal to that obtained by other flame methods, INTRODUCTION This investigation was undertaken in Bureau of Mines laboratories to develop a reliable, rapid, routine analytical method for determining lithium in lithium-bearing minerals. The requirements of the procedure were that the method should be applicable to the analysis of a variety of lithium-bearing ores and test products, and the results would be reasonably accurate for materials containing 0.05 to 8 percent Li20.

Jan 1, 1961

By John Nagy

Results of initial research by the Bureau of Mines are given on the dust explosion hazard of float coal and on the related factors of occurrence, rate of production, sampling techniques, transport, and deposition of float coal. Tentatively, it is suggested that where float coal deposits prevail, a mini-mum of 80 percent incombustible be maintained in the top 1/8-inch layer to neutralize the explosion hazard of the surficial coal deposit.

Jan 1, 1965

By Walter E. Lewis

A mothod of cutting St. Poter sandstono by streams of water under pressuro from nozzles and pumping the resulting, sand to the surface has roduced the cost of storm-sowor construction in the Minneapolis-St. Paul aroa. The hydraulic tunneling method, has boon in uso since 1934, and it is adaptable only to the lower part of tho St. Potor, sandstone, which lios within or just abovo the ground-wator levol. Tho upper part of the formation, immediately bolow tho Plattoville limestone, 18 comonted and camot bo mined by hydraulic mothods. The tunnel oporation observed in this instance is a main storm sowor starting at tho Mississippi Rivor below the 10th Avenuo SE bridge and will be drivon 6,000 foot at a grado of 1 foot por thousand undor the city of Minneapolis to Konnody and Arthur Stroots NE. A lateral storm sowor, which branchos from the main sovor at 8th Street SE, will oxtond from 10th Avonuo SE to 15th Avonuc SE. Tho tunnele are being drivon with the floor approximately at ground-wator lovol. All waters ontoring the main storm sower vill drain into the Mississippi Rivor. Tho main storm sewer cross soction is excavated to a roughly hox- agonal shapo 10 foot high by 10 foot wido at the contor. The upper half of the tunnol soction is solidly lined with either timber or stool. After all oxcavation is completed, the tunnel will be finished with a concrete circular lining 8 feet in inside diameter. The lateral storm sewer is excavated to a 5-1/2-foot by 7-1/2-foot section and will event- ually be finished with concrete to a modified horseshoe-shaped section 6 feet by 4 feet. Where the back or walls are considered unsafe during excavation, the upper half of the tunnel is lined solidly with timber. The equipment used by the Sower Division, City of Minneapolis, has been selected to meet a number of applications in storm-sewer work with diversified usage in mind. The sand pumps used on this job are rubber-lined, designed to work against a head of 100 foet. Either 4-inch or 6-inch diameter suction and discharge openings may be used. Other equipment, such as pipe, mine rail, flexible hoses, compressors, and general surface shop equipment, is drawn from a contral warohouse. It may be either new or used, depending on what is available at the warehouse. Much of the pipe and mine rail has been used for many years on several different tunnol jobs.

Jul 1, 1950

By Nar S. Dala1, Xianglin Shi, Val Vallyathan

"Electron spin resonance (ESRJ and cytotoxicity measurements were made on newly fractured silica to examine specifically the role of the fracture-induced, silicon-based radicals (Si· and SiO·) and silica-generated hydroxyl (·OH) radicals in the mechanism of the cell membrane damage by silica. The concentration of the Si· and SiO · radicals was controlled through decay processes, thermal annealing, and boiling, while that of the ·OH radicals was varied by using catalase, superoxide dismutase, KMnO, Na;iSeO:y ascorbic acid, and metal ions, and monitored via ESR spectroscopy. The dust's cytotoxicity potential was evaluated by measuring the silica-induced hemolysis and also by determining lipid peroxidation (using linoleic acid). From the comparison of hemolysis and ESR results it is deduced that the radicals play little or no role in the silica-induced hemolysis. However, the lipid peroxidation data indicate that the radicals might be involved in the initiation of an oxidative chain reaction leading to the macrophage membrane damage through lipid peroxidation. INTRODUCTIONThe biochemical mechanism of quartz-related pneumoconiosis is still not fully understood. It is believed, nevertheless, that one event of primary importance is the perturbation of cell membranes by the dust particles (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Parazzi et al., 1968; Reiser and Last, 1979; Shi et al., 1989; Summerton et al., 1977). The ensuing cell: membrane damage unleashes certain lytic enzymes resulting in additional cell injury and eventual fibrosis (Nolan et al., 1981; Summerton et al., 1977). Thus considerable effort is currently being made toward the understanding of the processes by which quartz particles disrupt the membrane of a red blood cell (RBC) or a pulmonary alveolar macrophage (PAM). A simple but important method of evaluating the membrane damage potential of a dust is the hemolysis test (Harington et al., 1971). Even though this test is used routinely for screening dusts for their cytotoxicity potential, the biochemical mechanisms underlying the cell lysis by many dusts, including quartz, is still controversial (Kilroe-Smith, 1974; Singh and Rahman, 1987), and this provided us the impetus for the present undertaking."

Jan 1, 1990

By Michael D. Fenton

The very modest-sized mineral industry of Afghanistan was burdened for another year with problems of internal strife occassioned by the presence of Soviet armed forces. Despite this, production of the few traditional commodities continued, and the mineral industry moved to develop additional mines and plants for both traditional and new products with considerable technical and construction assistance from the U.S.S.R. Among the limited range of mineral commodities for which production was reported, there were no startling changes between 1984 and 1985. Production of both coal and natural gas advanced only slightly, despite substantially higher 5-year plan goals, and cement output was down marginally. Probably the most significant development in 1985 was the Possibility that mine and/or smelter production of copper was initiated during the year.

Jan 1, 1987

By Chester L. Arnold, Reinhardt Thiessen, Alexander Lowy

"INTRODUCTION Peat is the accumulated mass of plant materials that remain after partial decay under specific conditions. In the swampy peat bogs dead material which falls on the surface immediately is attacked by fungi and aercbic bacteria. Decay under these conditions is rapid, but of relatively short duration, since the constant addition of new material soon forces the older layers below the water level, in this position, without access to oxygen, the plant constituents are attacked mainly by anaerobic bacteria, and decomposition proceeds slowly. The largest part of peat is contributed by the woody tissues of plants, the chief constituents of which are cellulose and lignin, together with a small proportion of hemicelluloses. During the normal process of biological decay celluloses disappear more rapidly than lignin. The result is a complex substance known as humin, from which the humic acids may be extracted.In 1826, Sprengel 5 found that when decayed plant materials were extracted with alinnli and the resulting black liquid acidified with mineral acid a brown gelatinous precipitate was formed. To this product, which was a brown amorphous powder when dry, he gave the name ""humic acid'. Since that time, chemists have used the name rather loosely to designate products which have been isolated by very diverse means from soils, decayed woods, peat, lignite, and coal. An excellent review of the early work on humic acids was published by Baumann 6 in 1909. This publication aroused the interest of Oden, who then investigated the humic acids. An account of Oden’s work, as a good survey of the literature, is contained in his monograph “Die Huminsauren”. 7"

Nov 1, 1934

By James P. Bennett

In this Bureau of Mines study, portions of four acidproof bricks (two red shale and two fireclay) were exposed to 20 wt pct RCI at 900 C for periods of 30 days. Three different techniques were selected to deter-mine volume expansion of these materials after exposure. Linear expansions ranging from about 0.02 to 0.12 pct were noted from Ta pin and dilatometer measurements. The use of strain gages to measure expansions was not successful. The red shale and fireclay brick with the lowest apparent porosities had the lowest expansions. Expansion data obtained by direct measurement of samples exposed for 30-day periods or by dilatometric measurement of autoclaved samples ex-posed for 2 h were comparable. This suggests the use of an accelerated autoclave exposure procedure for determining volume expansion effects of ceramic materials in acid environments.

Jan 1, 1985

In this U.S. Bureau of Mines report, proposed narrow-vein and longwall mining concepts using drill-split technology (described in part 1 of this series) and in situ liner concepts (described in part 2 of the series) are combined and applied conceptually to environmental problems. Proposed applications deal with (1) acid mine drainage (AMD), (2) solid waste disposal, (3) site remediation, and (4) pollution prevention through innovative industrial design. For control of AMD from abandoned hillside mine workings, it is proposed that source veins be re-mined, processed for residual values, then backfilled using an impermeable compound backfill mix. For solid waste disposal, "vertical landfills" are proposed, consisting of trash-backfilled underground rock quarries. Vertical landfill activities take place in in situ lined containments that geohydrologically isolate the mining-backfilling activities. Site remediation through the creation of in situ underliners, for the capture of toxic leachates, and pollution prevention through the underground storage of toxic, flammable, and explosive materials in in situ containments, are proposed.

Jan 1, 1995

By R. V. Ramani, A. S. C. Owili-eger

List of Numbers

Jan 1, 1974

By P. F. Sands, Michael Sokaski, M. R. Geer

The purpose of this investigation was to determine the advantage of using either a conventional sieve bend ahead of a vibrating screen or of attaching a sieve - bend screen surface onto a vibrating screen to serve as a scalping deck when dewatering or draining dense medium from fine coal . In dewatering , use of either the sieve bend or scalping deck increased the capacity of the vibrating screen tenfold and the recovery of coal finer than 0.5 mm threefold , with no sacrifice in the moisture content of the oversize product . In dense -medium drainage , either the sieve bend or the scalping deck reduced the amount of magnetite retained on the product of the vibrating screen , particularly when the medium was as dense as that characteristic of the underflows from dense - medium cyclones . The sieve bend was slightly superior to the scalping deck in dewatering , but the scalping deck was clearly superior in dense -medium drainage . Additional advantages of the scalping deck are lower cost and a substantial saving in headroom.

Jan 1, 1963

By F. N. Kissell, C. H. Elder, C. M. McCulloch

The applicability of the "direct method" for determining the methane content of virgin coalbeds was tested. Preliminary results indicate that the direct method, when applied to exploration cores, can be successfully used to estimate coalbed gas content and also approximately predict the total gas emission from a prospective mine located in the coalbed at the exploration site.

Jan 1, 1973

By E. P. Youngman

This paper is one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to can and ore rate mines in various foreign countries. This interpretation of the mining laws of the Irish Free State has been prepared from the best available material in Washington and is released subject to amplification and correction, if necessary, by American foreign-service officials. INTRODUCTION This paper is based upon the mines and minerals act, 1931, enacted by the Legislature (Oireachtas) of the Irish Free State (Saorstát Eireann), December 22, 1931, the lull title of which is "An act to establish a board to perform functions in relation to mines and minerals, to authorize the making of lenses of mines and minerals belonging to or vested in Saorstát Eireann, to name provider for facilitating the working of other mines and minerals and, for imposing restrictions on the working of minerals required for the support of buildings and works, to amend the law with respect to mines, and for other purposes incidental to the matters aforesaid.'

Jan 1, 1933

By D. J. MacDonald

This U.S. Bureau of Mines report reviews published information on synthetic berlinite (AlP04) and suggests experimental conditions requisite for its production. Berlinite is a piezoelectric material with potential use as a substitute for quartz in the crystal oscillators, which are components of electronic and electroacoustic equipment. Information gathered here (mostly from published sources) includes historical background, physical properties, end-use applications, criteria of quality, and physio-chemical factors involved in berlinite crystal growth. It is concluded that growing large high-quality berlinite crystal would require high-purity starting materials in an autoclave equipped with a noncorrodible liner and operated with temperature control of ±O.OO5 ac over a range of 250 to 350 ac.

Jan 1, 1995

By Arthur L. Murray

The first thought in the case of an accident or contagious disease is naturally that aroused by our humane instinct , how serious is the case and will the person recover ? The economic effects of such cases , owing to their many ramifications , are seldom realized either by those directing mining operations or those engaged in the labor of producing . This paper is based on the accident experience of the State of Utah and the number of cases of two well known preventable diseases , typhoid fever and smallpox , in that State for the fiscal years 1917-1918 , 1918-1919 , 1919-1920 , and 1920-1921 . The data and figures presented are from coal -mining camps only . W. W. Adams , mine- accident statistician of the bureau, contributed valuable corrections and suggestions . The economic results of accidents are considered first , and those of the two preventable diseases later .

Apr 1, 1922

By A. T. Iannacchione, D. G. Puglio

The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata. Trends established from mapping, including prediction of areas of high methane emissions, were extrapolated to unmined areas. "Wants" in the coalbed are of two types: Erosional and depositional. Erosional features occur where north-south-trending sand-filled channels cut into the coalbed. Variations in depositional environments have caused the coalbed to "split" into several thinner units. Slickensides, commonly indicative of unstable roof, are adjacent to and on the underside of sandstone channels; they were caused by differential compaction and by soft sediment sliding along the contact between the sandstone and adjacent shale. The frequency of unstable roof also increases where the interval between the Middle and Lower Kittanning coalbed is less than 30 feet. The zones of weakness at the contacts above and below the Middle Kittanning coalbed are the controlling factors for unstable roof in these strata. Methane emissions from the coalbed are controlled primarily by depth, fracture permeability, and rank of coal. Local geologic factors are coalbed thickness, associated rock strata, structure, and proximity to outcrop.

Jan 1, 1979

By George T. Faust, S. R. B. Cooke

"The Southern Experiment Station of the Bureau of Mines, United States Department of the Interior, in cooperation with the University of Alabama, is investigating the preparation of pulverized coal for fuel. In this study the relative amount of surface in various products and samples had to be assessed. Because of the familiarity with screens and because of the simplicity of using the inverse ratio of the opening for ascertaining the amount of relative surface in the respective sizes, screens down to and including 270-mesh were used. This choice was made in full cognizance of the irregularity of screens, but it seemed that if the same screens were used throughout all the tests the relative values would be satisfactory.In dealing with the subsieve sizes, pneumatic elutriation was used to make several fractions to extend the sizing analysis into the range of hypothetical screens. This kind of a sizing analysis was thought necessary because it is familiar to all operators, and, furthermore, it is amenable to several ways of plotting curves that bring out the characteristics of various coals and various methods of grinding.The method of obtaining the data from which to set up the hypothetical screen scale is the subject of this paper. It consists in determining the average projected area of the particles in the respective elutriated products. By extending the ""area method"" to sieve sizes, a factor is found that may be applied to the subsieve sizes, and thus the scale is projected in a regular manner. This method avoids contentions about specific surface and steers clear of ""average diameter"" except as material sized on screens may be said to have an average diameter."

Aug 1, 1939

By David C. Scott

Between 1990 and 1991, the Bureau of Mines studied the mineral resources of the Kaibab National Forest to appraise the resources present and to determine the types of deposits, and their location. The study included a comprehensive literature search and a limited amount of field investigation of minerals and mining activity in and near the Forest. Small amounts of copper with lesser amounts of gold and silver have been produced from limestone-hosted, strata-bound deposits in the North Kaibab and Tusayan Ranger Districts. In addition to these small metallic deposits, volcanic cinders, pumice, flagstone, and sand and gravel have been quarried in the Chalendar and Williams Ranger Districts. At least ten uranium-mineralized breccia pipes have been identified in the Tusayan Ranger District, One of these, the Canyon pipe, contains a high-grade uranium ore body with associated silver, copper, lead, vanadium, and zinc. The mine permit for the Canyon pipe has been approved and the mine shaft head frame erected.

Jan 1, 1992

By T. H. Jeffers

The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials such as sphagnum peat moss for extracting metal contaminants from waste waters. The beads, designated as BIO-FIX beads, have removed toxic metals from over 100 waters in laboratory tests. These waters include acid mine drainage (AMD) water from mining sites, metallurgical and chemical industry waste water, and contaminated ground water. Following the laboratory studies, cooperative field tests were conducted to evaluate the metal adsorption properties of the beads in column and low-maintenance circuits, determine bead stability in varied climatic situations, and demonstrate the beads' potential as a viable waste water treatment technique. Field results indicated that BIO-FIX beads readily adsorbed cadmium, lead, and other toxic metals from dilute waters; effluents frequently met drinking water standards and other discharge criteria. The beads exhibited excellent handling characteristics in both column and low-maintenance circuits, and continued to extract metal ions after repeated loading-elution cycles. Based on laboratory and field data, cost evaluations for using BIO-FIX technology to treat two AMD waters were prepared. Operating costs for BIO-FIX treatment, which ranged from $1.40 to $2.30 per 1,000 gal of water treated, were comparable with chemical precipitation costs.

Jan 1, 2010

By E. S. Leaver

The mineral value in the ores from the Mother Lode mining districts of California is almost entirely gold, Although many mines have produced extremely high-grade ore the usual mill grade averages approximately $7.00 gold per ton. Fully 80 per cent of the gold has been and is now being recovered by amalgamation. Various methods have been introduced to recover the gold that was not obtained by the amalgamation processes. They include vari¬ous kinds of gravity concentration which in some cases were followed by chlorination or cyanidation. The usual practice includes only stamp battery, plate-amalgamation, and vanner concentration. In the very early practice the tails were run to waste through the main drainage streams of the different mining districts. During later years very large storage dumps have been impounded. These old tails, together with those being saved from present mills, furnish the problem discussed in this article. The clean sand portion of these mill tails is amenable to the usual cyanidation. The slime portion contains the major amount of the gold lost, but it also contains 1-1/2 to 3 per cent carbon, which precludes direct cyanidation of this part of these low-grade waste tails. The black carbonaceous slime portion is the particular problem considered in this report.

Jan 1, 1930