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By C. B. Barmore, B. W. Gandrud, B. M. Bird

"The Bradford mine of the Alabama By-Products Corporation is located in the Warrior coal field of Alabama, in the northern part of Jefferson County, about 25 miles north of Birmingham. The coal mined from the Black Creek bed at this point is not considered to be ideal for coke making by itself but because of its exceptionally low ash content is mixed with the higher-ash coking coals from other beds of the district to control the ash content of coking mixtures. Further reasons for using this coal only as a diluent of the higher-ash opals are that the thinness of the bed renders the production costs relatively high and the reserves are somewhat limited.This paper, which is the fourth of a series on the washability of Alabama coals, Like its predecessors dealing with the Mary Lee beds and the Clark bed,6 contains screen-sizing and float-and-sink tests of a representative sample of the raw coal, and flakiness tests showing the proportions of flaky particles in certain selected sizes. However, inasmuch as the float-and-sink tests of the coarse sizes showed excellent liberation of coal from impurities, crushing tests have not been considered necessary.The data on which this report is based have been obtained in connection with an exhaustive study of coal preparation in Alabama now being conducted by the U. S. Bureau of Mines and the University of Alabama with the cooperation of the different coal operators. As the work progresses other papers will follow containing further data on Alabama coals and giving results obtained in preparing these coals by various methods."

Apr 1, 1931

By G. L. Oldright

This paper is the twelfth of a series on smelting in the lead blast furnace and the fifth dealing with blast-furnace gases. It was noted in Report of Investigations 2957 that the gases evolved from the top of the lead blast furnace at Tooele were similar in composition to those from the top of an iron blast furnace. It was noted in Report of Investigations 3095 that at Kellogg, where a smaller percentage of coke on charge and shorter stock column were employed, the gases evolved were much less reducing. At times there was a considerable amount of oxygen in the top gases at the second plant. More SO2 was also evolved from sulphides in the charge. Then operations were conducted as at Kellogg, the gases were alternately reducing and oxidizing. This paper deals with the gases evolved in smelting a charge containing more zinc than at either of the other two plants with about the same amount of coke as was used at Kellogg,: To compare other factors influencing the composition of the gases, it may be noted that at Tooele the approximate height of the charge column was 15 feet, at Kellogg 9 feet and at Trail 13 feet. The furnaces have about the -same cross-sectional area- tog. The furnaces at Tooele are about 6 inches wider at the tuyeres, being 54 inches wide against 48 for the other two plants. At Tooele and Kellogg the furnaces are fed at the top from bottom-dump cars. At Trail the charges are dumped from Decauville cars (bottom cars which dump when tilted), which run on tracks placed on both sides of the blast furnaces. The hoods through which the waste gases are conducted are directly above the shafts of the furnaces. The flues for removing the effluent gases lead off from under the charge floor at Tooele and Kellogg. (Charging and distribution of the feed in the furnace covered later in a rate paper of series.)

Jan 1, 1934

By F. H. Gibson

In recent years physico-chemical techniques have been applied for rapid analysis of coal and coke ash as replacements for classical wet-chemical methods. Although the classical methods are accurate, they are time consuming because many chemical separations are necessary to complete an analysis, and they require skilled analysts for accurate work (12).4 For the past several years the Bureau of Mines has applied some of the newer physico-chemical techniques in its continued search for new and improved methods at analysis. The methods of analyzing coal and coke ash evolved from this work include spectrophotometric methods far SiO2, A120, , Fe203 , TiO2, and P2O5; chelatometric titration for CaO and MgO; and flame photometry for Na20 and K2O. The methods are rapid and direct, are suitable for analyzing a group of samples at the same time in production work, and dire results with almost the same accuracy as classical procedures. With the new methods, complete analyses in duplicate can be obtained at a rate of 2 to 3 times that of conventional methods.

Jan 1, 1962

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 Scott Turner

I have been asked to speak briefly about recent progress in the mining industry of the United States, and to touch on the general advancement of en- gineering science as applied to mining. By recent, I shall mean within the past 20 or 30 years. Such a period includes a great many of the changes which are of particular interest to the present generation of engineers, and the undergraduates of today will hardly turn back farther than the beginning of the present century in their study of develop- ment of methods and processes. Also, my own professional life spans this period, and I have seen or have been aware of most of these developments as they were taking place. In my review of developments, for the sake of simplicity and clarity, I shall deal separately with improvements in metal mining, coal mining, mechanical and electrical machinery for mines, metallurgy, petroleum engineering, and safety practices. Under each of these headings I have set down what appear to me to be the outstanding changes brought about during the past 2 or 3 decades. Other points will occur to other engineers; I do not represent that the following re- view is complete; it is only intended to be suggestive. In general, improvements in mining and metallurgical practices have come gradually, the charges being effected little by little, simultaneously in widely scattered places, and through the experience and inventive genius of many men. These changes have has small beginnings, and are generally the cumulative result of many steady and unsensational progressions, which still continue. What we today might be inclined to consider the culmination of a series of betterments in mining is, of course, but an instantaneous phase of developments which will continue in the future at even a more rapid pace than they have in the past. We are looking at but a flesh of a moving picture, with an endless reel to come after we finally leave the theatre. Behind all the changes in the mineral industry, the driving force has been the increasing demand of an expanding population for more metals and minerals with which to advance civilization. More people, with an increasing per capita consumption, together with the exhaustion of the richer but smaller, and more

Oct 1, 1930

By E. B. Swanson

Atlantic seaboard refining and marketing companies , dependent largely upon other producing and refining areas for the crude and refined petroleum needed to meet the demand for petroleum products within the Atlantic Coast States , reported an increase in 1929 receipts of 2,542,000 barrels of crude petroleum and 13,479,000 barrels of gasoline over the quantities received during the preceding year . The relatively large expansion in gasoline receipts undoubtedly resulted from the unexpected increase in gasoline consumption which characterized the petroleum industry during 1929. Gasoline receipts from California increased 6,354,000 barrels and shipments from foreign countries were 5,381,000 barrels in excess of the 1928 figures , while receipts from Gulf Coast ports , the major source of outside supply, declined 811,000 barrels . Shipments of domestic crude oil by tanker from Gulf Coast ports during 1929 continued the average annual increase of approximately 7,000,000 barrels which has been recorded during the five years of this annual survey . These shipments have increased from 72,556,000 barrels during 1925 to 99,828,000 barrels during 1929. Shioments of Mid- Continent crude by pipe- line to Atlantic Coast refineries have , on the other hand , dropped from 11,903,000 barrels in 1925 to 1,409,000 barrels during 1929. Receipts of foreign crude oil declined 1,461,000 barrels from the preceding year . : Gasoline demand within the Atlantic Coast area reached a total of 123,345,000 barrels , an increase of 15.7 per cent over 1928. Gasoline production increased 4,157,000 barrels , while tanker receipts were nearly 11,000,000 barrels larger than in 1928. Indicated shioments from Appalachian refineries were somewhat larger than in the preceding year . Gasoline production showed an average of 33.5 per cent of the crude throughout , as compared with 31.5 per cent in 1928 and 32.7 per cent in 1927. Cracking operations accounted for 44.6 per cent of the gasoline produced , as compared with 40.6 per cent in 1928 and 35.3 per cent in 1927. Gas oil and fuel oil production averaged 52.8 per cent of the crude throughput , as compared with 55.1 per cent in 1928 and 49.5 per cent in 1927 , the decline reflecting the smaller quantities of foreign crude refined during the year .

Nov 1, 1930

By G. L. Oldright

The data presented in this paper were collected et the smelter of the Consolidated Mining A Smelting Co. of Canada, Limited, Trail (Tadanac), British Columbia, through the courtesy of S. G. Blaylock, vice president and general manager; James Buchanan, smelter superintendent, George Murray, assistant smelter superintendent; and the staff members listed in Paper XI, Report of Investigations 3243. INTRODUCTION This paper is the twelfth of a series on smelting in the lead blast furnace and the fifth4 dealing with blast-furnace gases.

Jan 1, 1934

By I. AITKENS

The precious stones rubies and sapphires are transparent varieties of the mineral corundum . Essentially they are aluminum oxide , but the aluminum is often replaced. by small amounts of chromium , titanium , or iron . The chromium is said to give a red color , titanium a blue , and iron a yellow . True rubies range from rose to a somewhat purplish red and are sometimes termed " oriental rubies " to distinguish them from spinel rubies , stones of inferior hardness , density , and value . " Oriental rubies " are very rare , and the so-called " pigeon's blood" variety is the most valuable . Sapphires normally range in color from palest blue to deepest indigo , but actually all precious varieties of corundum of any other color than red are called sapphires . The most esteemed tint is like that of the blue cornflower . Colorless corundum of gem quality is called white sapphire ; the yellow variety is described either as yellow or as golden sapphire ; and the pale pink is classed as pink sapphire . The word " oriental " is also used as a prefix in naming varieties of corumdum of less popular colors . For instance , oriental emerald is used for green corundum, oriental topaz for yellow , and oriental amethyst for violet to purple varieties . The chief physical characteristics of rubies and sapphires are hardness , adamantine luster , and moderately high specific gravity ( 3.9 to 4.1) . Next to the diamond, corundum is the hardest of all minerals ; in fact , the sapphire is number 9 on Moh's scale , ranking between the topaz and the diamond. Rubies crystallize in 6-sided prisms terminated by flat faces and other varieties of corundum with twelve inclined faces , six above and six below , meeting in a girdle . Corundum is doubly refractive , with a direction of single refraction running parallel to the edge of the prism . The refractive indexes are very constant, the ordinary index ranging from 1.766 to 1.774 and the extraordinary index from 1.757 to 1.765. The double refraction always remains the same.

Aug 1, 1931

By W. T. Benson

The nickel-bearing laterite deposits in the Pine Flat and Diamond Flat areas, Del Norte County, Calif., were investigated by the Bureau of Mines to determine the extent and nickel content of the two deposits and the amenability of the ores to metallurgical treatment. The work was based on drill-hole sampling and metallurgical tests in which attrition scrubbing and sizing, reduction roasting, and magnetic separation were used. Results of the sampling indicated that the deposits are comparatively small and are marginal or submarginal in grade. Metallurgical tests showed that no separation of cobalt from nickel and iron was made by sizing; however, a large portion of the chromium was separated. Reduction roasting and magnetic separation did result in upgrading the iron, nickel, and cobalt, and the simultaneous rejection of chromium.

Jan 1, 1963

By C. O. Hawk

As an exploratory effort to produce useful products from coal by a new path, the Bureau has made a few experiments on the fast heating of finely ground coal particles by irradiation with a flash of high intensity light. The flash was produced by an electrical discharge at high voltage through a xenon-filled tube. The flashes lasted from 2 to 3 milliseconds. The reaction took place in small sample tubes, ½ inch-dimeter by 4 inches long, and with small amounts of coal (total amount charged 0.1 gram, probable effective amount not more than 20 milligrams). Average particle size of the coal, estimated on a numerical basis, was 20 microns. Temperatures reached were evidently quite high, because all products obtained in quantity were characteristic of high temperature pyrolysis. Apparently, conversion of the coal was extensive where isolated particles received the full benefit of a flash. It seems particularly significant that acetylene was present in appreciable amounts--comprising almost 3 percent of the total gaseous product in one case. This is good evidence of a short heating period to very high temperature (well above 1,000° C) followed by rapid quenching. Although the results are interesting, they do not suggest any immediate practical application.

Jan 1, 1963

By N. S. Dalal, X. Shi, V. Vallyathan

"Correlated spectroscopic and cytotoxicity measurements were made on newly crushed silica to find whether the fracture-induced, silicon related (Si-0· or Si· type) free radicals play a direct role in the mechanism of hemolysis by silica particles. The free radical content of the silica particles was controlled through the radical decay, thermal annealing, and boiling processes, and was followed with electron spin resonance spectroscopy. Portions of the same sample were evaluated for their hemolytic potential, employing sheep erthyrocyte and optical absorption techniques. The results indicate little, if any, correlation between the amount of the silicon-based radicals and the hemolytic potential of the fresh dusts, but these or related radical sites might be contributors to silica cytoxicity and fibrogenicity via peroxidative pathways .INTRODUCTIONIn an earlier convnunication (1.) from our laboratory it was reported that mechanical crushing of coal and quartz under normal air atmosphere generates free rad;cals on the particle surfaces, and that these radicals decay with time, hence pointing to a higher toxicity of fresh dusts in relationship to pneumoconiosis and silicosis. More recently Fubin; et al.(2) have also reported the detection by electron spin resonance (ESR) of the formation of SiO· and Si·-type of radicals from quartz particles crushed under atmospheric conditions. In agreement with earlier ESR studies on single crystals of quartz crushed under high vacuum (10-10 torr) (3) and subsequent exposure to air (3), and to other gases (4), these radicals were identified (2) as being formed by the hemolytic cleavage of the Si-0-Si bonds and the reactions of the Si· and SiO· ,radical with atmosphere. Fubin; et al. (2) also suggested that these radicals might be involved in the mechanism of the fibrotic action by silica, either by transforming the particle surface into a selective oxidating agent or as an initiator of a sequence of reactions leading to fibrosis. Earlier Gabor and Anea (5) had reported that lipid peroxidation caused by free radicals on the silica surface might be involved in the red blood cell membrane damage. Thus far, however, no parallel cytotoxicity, fibrogenicity, and free radical studies on a given Quartz dust sample have been reported, except for some earlier work from our laboratory (1,6,7). We now present more recent results obtained from parallel cytotoxicity, fibrogenicity, and free radical measurements on a freshly made quartz dust. The dust’s free radical content was measured using ESR spectroscopy while its cytotoxicity poteni1al was estimated via hemolysis. Hemolysis was employed as the tox1c1ty test because it 1s a widely used method for estimating the potential of a dust for disrupting the cell membrane (8). The f1brotic potential was followed.by measuring the dust-induced lipid perox1dat1on. us1ng linole1c ac1d as a model lipid. As discussed below, the results obtained suggest new clues.to the mechanism of the Quartz-related cytotoxicity and fibrogenicity."

Jan 1, 1988

By M. Clair Smith

This report is one of a series describing exploration, development, mining, and processing of mineral deposits in the United States. The reports are prepared and published by the Bureau of Mines in cooperation with various mining companies The purpose of the reports is to promote development and conservation of our natural reserves by disseminating technological information on mining and milling procedures and related practices at operating mines. Simplot Silica Products, Inc., mines and processes a friable silica sandstone. The finished products are sold for use in glass manufacture, foundries, chemicals, and special applications.

Jan 1, 1959

By E. L. Sweeney

The mine and mill of the Davis-Dunkirk Lines, Inc., are about 16 miles by road south of Prescott, Ariz., which is the nearest railroad point for receiving mine and mill supplies and for shipping concentrates to smelters. A good trucking road reaches within 2 miles off the property, but from that point the grade is very steep. Outgoing loads are limited to 2 tons. The topography near the mine is exceedingly rugged, and the area is slightly wooded. The climate is mild excepting in a few winter months, when the snowfall is heavy. Electric power is secured by way of a 4 1/2-mile, high-tension line connecting with the main line of the Arizona Power Co. The concentrator was intended to treat 60 tons or more daily of gold-silver-copper ore and make a single gold-silver-copper concentrate for shipment to a copper smelter.

Jan 1, 1933

By F. D. DeVaney

[In the course of the investigation by the U. S. Bureau of Mines and the Missouri School of Mines and Metallurgy at the Mississippi Valley experiment Station at Rolla, Mo., on the beneficiation of the low-grade manganese ores of the country, some samples from the Cuyuna District, Minn., have been examined. The work was done under the direction of W. H. Coghill, supervising engineer of the Mississippi Valley Experiment Station. Josoph and Kinney5 in venting about the relative importance of Minnesota deposits of low-grade ore compared to the total reserves say:]

Jan 1, 1930

By Floyd D. Everett

The J. B. fluorite deposit is in the Washington mining district, southwestern Beaver County, Utah (fig. 1). Fluorite outcrops were found during 1942, and three lode claims wore located. Little work was done on the property until October 1943, at which time the Bureau of Mines started development to determine the subsurface extent of the fluorite mineralization exposed at the surface. The most prominent rocks in the J. B. mine area are porphyries, which vary considerably in composition. Dacite porphyry appears to be the most common host rock for the fluorite-quartz-calcite lenticular masses. The dacite porphyry in the area is highly brecciated over a strike length of more than 1 mile. Fluorite deposits in the brecciated zone cover a strike length of approximately 400 foot. The fluorite lenses range in length from 40 to 200 feet and in width from 4 to 10 feet (fig. 2). The Bureau of Mines work on the J. B. property was started in October 1943 and completed in October a year later. The work consisted of surface trenching by bulldozer and hand methods, shaft sinking, drifting, and crosscutting. Eleven trenches totaling 1,800 linear feet were excavated. An inclined shaft was sunk to a depth of 105 feet, and from thin shaft 577 feet of drifts and crosscuts were driven to outline the extent of the mineral deposit (fig. 3). Two hundred ninety-seven samples were taken in the surface trenches and underground workings. The locations of the samples and analyses arc shown in accompanying figures and tables. Results of metallurgical tests comprise the concluding section of this report.

Jan 1, 1950

By G. J. Conroy

This Bureau of Mines study was initiated to determine whether or not a large-scale investigation of 400-Hz applications in coal mines was justified as a means of increasing safety in operations due to size and weight reductions in portable and other mining machinery. Potential uses for 400-Hz power in mining operations are explored, and cost and size comparisons with 60-Hz systems are made. The use of variable-frequency motor drive is suggested for conveyors. The conclusion was reached that there is no significant potential safety increase due to a general size and weight reduction, as the fact of such general reduction cannot be demonstrated.

Jan 1, 1974

By J. W. Town

The Bureau of Mines conducted phosphate beneficiation studies to determine the influence of mineralogical and textural features on the recovery of phosphate from select bed and composite samples representing different phosphate rock types of the western Phosphoria Formation. Batch heavy-liquid tests showed that ore grade) pellet size, and type of interstitial material were significant parameters affecting concentrate grade and recovery. Recoveries at acid grade (31.5 percent P2O5) ranged from 98 to 56 percent. Liberation was essentially complete at 28 mesh, and recoveries tended to drop when overgrinding occurred.

Jan 1, 1966

By H. P. Hermance

The Ely mine, which at one time was the largest producer of copper in the United States, has been idle for the past 30 years. A remarkably continuous ore shoot probably averaging 100 feet wide and 19 feet thick was mined on about a 25° slope for 3,400 feet on the incline. The ore was massive sulfides containing chalcopyrite, pyrrhotite, pyrite, and sphalerite. The estimated production of the Ely mine is 400,000 tons of ore averaging 3.3 percent copper. Because of the critical position of copper during the recent war, a search for extensions and recurrences of parallel ore shoots at the Ely deposit seemed warranted. The Bureau of Mines surveyed selected areas by geophysical methods, diamond-drilled nine holes, and sampled mine dumps during its investigations, which began in 1942 and terminated in 1946. The diamond drilling totaled 5,229 feet. The logs of the holes include chemical analyses of mineralized sections.

Jan 1, 1949

By K. C. Dean

During the investigations of the occurrence of manganese in the Western United States, a Bureau of Mines examining engineer collected samples frame two properties in Beaver County, Utah. As the ores were too low in grade to be acceptable by manufacturers of ferromanganese, beneficiation studies were made to determine the amenability of the ores to concentration. The Steelville property is about 37 miles southwest of Frisco, Utah. The deposit is an example of manganese occurring as a replacement of limestone in a bedded vein or as layers in limestone associated with shale and rock decomposition products. The Susie Q deposit, about 33 miles southwest of Milford, Utah, is also a tabular replacement deposit in limestone, apparently of limited extent. Test work was done on representative samples of 2-ton lots obtained by the examining 'engineer from each of the properties mentioned.

Jan 1, 1951

By Jon I. Voltz

The U.S. Bureau of Mines has conducted fundamental coal fragmentation studies to evaluate the effects of impact energy and direction of bedding planes on dust generation, size distribution, and impact-output energy relationships. Product size distributions were obtained for the fragmented samples by screening to minus 150 mesh. The minus lS0-mesh fines were analyzed with a light scattering photometer with a measurement range of 176 to 1.9 /.tm. Increased input energy produced a significant increase in the weight of plus 3/8-in material for impact perpendicular to the bedding planes. No significant trend was observed for parallel impact. Impact direction had little influence on dust size distribution, and input versus output energy relationships. As expected, total airborne dust measured at time of impact and percent particulates below 11 /.tm in size generally increased with increased input energy for both directions of impact. Energy used for sample fragmentation increased with increased energy input.

Jan 1, 1989