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By Eric E. Ungar

Some fundamental facts regarding noise are summarized. Guidelines for reducing plant noise are indicated, and simple means are discussed for determining, whether quieting of specific equipment items will reduce plant noise significantly. Design and installation recommendations are made for quieting chutes by means of dams, impact cushioning pads, impact shields, and damping materials, and for quieting; screens by means of resilient decks, lined screen bottoms, drive mechanism enclosures, and side plate additions. A brief account is appended of the wear and productivity performance of resilient materials observed in three cleaning plants.

Jan 1, 1976

By Jan C. Still

The Glacier Bay subarea is that part of the Juneau Mining District (JMD) within Glacier Bay National Park and Preserve (GBNP). It is the western portion of the JMD and consists of the land between the Fairweather Range crest and the Takhinsha and Chilkat Ranges crests (excluding that land east of Excursion Inlet.) Figure B-1 shows the area. It is bounded on the north by the Alaska-British Columbia International boundary, to the south by Cross Sound and Icy Strait, and contains Glacier Bay. During 1975 -1977 the Bureau conducted a detailed study of the occurrences, prospects, and deposits in GBNP (B_4).2 This work was in cooperation with the U.S. Geological Survey (USGS) under the provisions of the Wilderness Act (Public Law 88-577). As a follow up to this earlier Bureau work, limited studies were conducted, during 1985 and 1986, as part of the JMD study. This report covers the most important aspects of the earlier studies and the 1985 and 1986 studies. ACCESS The Glacier Bay area may be reached through Gustavus airport, a paved strip which is serviced by scheduled jet airliners in the summer and air taxi services year-round. The airport is connected to Bartlett Cove (GBNP headquarters) by an all-weather road. No other roads exist in the area except a skid road to the LeRoy Mine and mill in the Reid Inlet area. Much of the Glacier Bay area is accessible through the salt water inlets and fjords which are part of Glacier Bay. Cruise ships, charter boats, and fishing boats visit these inlets and fjords during the summer months. Elevations within the area range from sea level to over 15,000 feet in the rugged Fairweather Mountain Range. More remote areas are accessible by small boat, foot, or helicopter. Glacier ice is a year-round hazard to navigation in Glacier Bay, and during the winter months some of the more northerly inlets are frozen.

Jan 1, 2012

By Clarence A. Wright, JAMES T. NORTON, JAMES G. PARMELEE

The object of this paper is to give to mining companies and to all others who are interested some idea of the possibilities in the treatment, by differential flotation, of lead-zinc ores of the Coeur d'Alene region and other districts. The purpose of these investiga.. tions is not to evolve a differential flotation process that would replace present methods of gravity concentration but rather one that could be applied to the relatively fine material and slime produced in the mills and treated unsuc_pessfully by gravity methods or by flotation. It is expected, of course, that the products to be obtained by differential flotation would be of much better grade than those now produced by flotation in the Coeur d'Alene mills. In view of the fact that it has been difficult to obtain representative samples of flotation feed from the mills, owing to the necessity of shipping the material wet and free from oil or other foreign matter that might be deleterious to the differential separation of the sulphides, the writers have felt justified in running flotation tests with the mill feeds in order to ascertain whether a differential separation of the sulphides could be effected. However, two different lots of flotation feed were tested for differential flotation, and the results of tests of one of these are given in this report. It is hoped that it will be possible later to test out the flotation feed for differential flotation on a large scale in some of the mills. This paper covers part of the investigations carried on by the United States Bureau of Mines in cooperation with the Idaho Bureau of Mines, the University of Idaho, and certain mining companies of the Coeur d'Alene region. Although the results of the tests included in this report are not to be considered final, they indicate possibilities and may suggest others leading to a solution of the problem of separating lead and zinc sulphides by differential flotation in the treatment of certain ores.

Jan 1, 1921

By B. D. Nash

The object of this research was to investigate the technical feasibility of preparing chromium metal by the thermal decomposition of bisbenzene chromium. Bisbenzene chromium, a pi-bonded sandwich type organometallic compound, was thermally decomposed under reduced pressure to form a metal plate on a heated substrate. Metal recovery was close to 100 percent of theoretical, with deposition rates up to 20.8 mg/hr/cm2. Metal purity was dependent not only upon the purity of the starting material, but also upon the sublimation rate of bisbenzene chromium. Total detectable metallic impurities ranged from a low of 18 ppm to several hundred ppm. In general, metallic impurities were less than 100 ppm. Carbon, the major nonmetallic impurity, ranged from less than 0.3 percent to more than 10 percent. The carbon contamination is most likely a result of the decomposition of the organic portion of bisbenzene chromium. An unusual property of some of the deposits was their outstanding corrosion resistance. Unlike pure electrolytic chromium, which dissolves readily, these deposits were insoluble in hot mineral acids.

Jan 1, 1968

By M. H. Chetrick

An important factor in the design and operation of a lignite-gasification plant is knowledge of the thermal requirements. These not only vary with different-size plants but also with the operating conditions for a plant of given capacity. Thermal data have been collected since 1945 from a commercial-scale lignite-gasification pilot plant operated by the Bureau of Mines at Grand Forks, N. Dak. The description and operation of this plant and a study of the gas-composition data have already been described in previous reports (1, 2, 3, 4, 5).2) / This investigation was made to review the thermal data taken in tests and to correlate them in terms of the fraction of undecomposed steam and the H2:CO ratio.

Jan 1, 1953

By Roy E. Peterson

The Bureau of Mines has been developing and evaluating methods for beneficiating the large deposits of nonmagnetic (oxidized) taconite located on the western Mesabi Range. In this segment of the research, a sample representing about 0.5 billion tons of nonmagnetic taconite from near Grand Rapids, Minn., was beneficiated using a reduction roasting, magnetic separation, flotation process. The sample contained 32.1 pct iron and 49.1 pct silica. Tests were conducted both on a bench scale and with a 1,000-lb/h pilot plant. In the bench-scale research a con-centrate containing 69.0 pct iron and 4.5 pct silica was produced with an iron recovery of 82.1 pct. In the pilot plant, reduction roasting was conducted in a 35-ft kiln using lignite as the reductant and major source of fuel. Dust from the kiln exhaust was pelletized and recycled to the kiln. The roasted taconite was beneficiated by magnetic sep-aration and flotation to produce a product containing 67.9 pct iron, 5.5 pct silica, and 69.7 pct of the iron in the kiln feed. The cyclone separation in the grinding circuit was sharpened by demagnetizing the cyclone feed in a 400-Hz, 1,000-Oe magnetic field.

Jan 1, 1983

By D. H. Baker

THIS REPORT presents the technique and equipment used in determining the hardness of titanium sponge. Detailed descriptions are given of the methods used in preparing test samples for chemical analysis and hardness testing, the method of melting and surfacing test ingots, and the technique of reading Brinell-hardness impressions. The arc-melting furnace described, for which engineering drawings are included, will produce from 70 to 90 double-melted buttons each 8 hours of operation. Experimental data are also presented depicting the effect on hardness of the methods of surfacing specimens, temperature of test specimens, and the effect of time at test load. These data show that surfacing of the specimen involves no critical machining operations but that the test surface must be paralleled by a relatively flat surface for contact with the anvil of the Brinell tester. The heating of a specimen to 150° C. during surfacing does not materially affect the results if the ingot is cooled to room temperature before the hardness impressions are made. The optimum time at load appears to be approximately 30 seconds, but load times of as much as 1/ ½ minutes will not cause major errors.

Jan 1, 1959

By Jerry W. Ramsey

The Bureau of Mines examined a low-, a medium-, and a high-volatile Pennsylvania anthracite by densimetric methods using four mesh si.s of each anthracite. Using high-pressure mercury the macropore volumes and distributions of these pore volumes determined, densities in mercury were calculated, and specific pore vo1.r. ware obtained from these mercury densities in conjunction with helium densities. The helium densities were also used with the ultimate analyses of these anthracites in calculating structural parameters by statistical densimetric methods. The effect of 106 or 108 rads of gamma irradiation in the presence of air and in vacuum upon the properties studied with two mesh sizes of each anthracite. Results of the statistical densimetric method seem to show some breakdown of condensed ring structural units at the lower irradiation level, with subsequent polymerization at the longer period of gamma irradiation. The structural parameters obtained also indicated that in going from high- to low-volatile anthracite, either the number of condensed rings per structural unit increased, or the degree of polymerization increased.

Jan 1, 1965

By P. G. Clites

The Bureau of Mines developed techniques for induction melting of titanium in a split, water-cooled copper crucible. Calcium fluoride, which was used as an inert slag cover during melting, formed an insulating layer of solid slag between the ingot and the crucible wall. This thin layer of slag effectively insulated the ingot from the crucible and prevented the molten metal from shorting across the slits between adjacent segments of the crucible. The technique provides a means of melting loose titanium sponge and scrap and eliminates the need for fabricating a consumable electrode. This report describes the equipment developed and compares ingots produced from two varieties of titanium sponge, from titanium scrap, and from previously melted titanium with ingots prepared by vacuum-arc melting and electroslag melting. A melting scheme was also proposed and evaluated whereby loose titanium sponge was consolidated into a first-melt ingot for vacuum-arc remelting.

Jan 1, 1969

By R. R. Sayers

The increasing use of hydrogen fluoride (annual consumption now exceeds 500,000 pounds (1)4/) directly and its occurrence as a byproduct of the utilization of fluorine compounds in the mineral industries, especially in metallurgical processes and in the refining of petroleum products, has aroused interest in its toxicity, and a brief review of the literature, with special reference to the hazard of poisoning in the mineral industries, seems to be opportune. Recently, residents in the vicinity of aluminum plants have been complaining of injury to livestock and vegetation as well as to their own health from the gases discharged into the air during operation of the plants, hydrofluoric acid gas apparently being the offender. The comparatively recent utilization of hydrofluoric acid in the alkylation process for the production of high-octane gasoline has raised the question of the hazard of poisoning in the petroleum Industry. In addition, the use of fluorine-containing refrigerants has extended the potential al exposure outside of industry (2).

Jan 1, 1945

By Daniel G. DiCanio

This report describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents in underground coal mines. The study undertook to identify and quantify the elements of accident costs, including field visits to coal mines, insurance carriers, and public agencies. The mathematical models developed for each tangible element of accident cost are presented in Volume I -of the report. A listing of the computer programs which comprise the model and instructions for using the programs are presented in Volume II. Statistical distributions of mining family characteristics, data on 95 miners killed in underground accidents, and other basic data used to develop the model are presented in Volume III. Application of the model to a data base of 9,286 accidents which occured in underground bituminous coal mines during 1974 yielded a total of $56,900,000 in tangible costs to industry, mining families, and public agencies. Loss of income to the families of miners injured or killed in these accidents accounted for 47 percent of the total.

Jan 1, 1976

Aluminum Production. -By October 1, Aluminum Company of America will restart a 35,000-ton-per-year unit at its aluminum smelter at Rockdale, Tex., restoring that facility to its full capacity of 325,000 tons annually. Primary Ingot Price Increase. -Most U.S. aluminum producers in mid-September were quoting a price of 72 cents per pound for primary aluminum ingot. On September 19, Kaiser Aluminum & Chemical Corp. announced that it would increase the price of primary aluminum ingot 4 cents to 76 cents per pound.

Jan 1, 1980

By S. J. Pearce

There are a number of methods for determining relatively small quantities of sulfur dioxide in air. However, those methods require fairly elaborate apparatus and laboratory facilities. Frequently in industrial hygiene surveys it is desirable to have a simple arrangement to obtain "on the spot" determinations. This has been accomplished for concentrations of sulfur dioxide of hygienic significance by using the midget impinger and decolorizing a starch-iodine solution.

Jan 1, 1948

By Martin H. Stanczyk, I. L. Feld

Continuous open - circuit attrition grinding of a coarse commercial kaolin to produce paper - coating clay , which must have a particle size analysis of 70 percent or more minus 2 - micron equivalent spherical diameter ( esd ) , was studied by the Bureau . The coarse clay , containing about 11 percent minus 2 -micron esd material , was ground in a 10 - inch- diameter attrition grinder using continuous single- and multiple - stage grinding circuits . The clay feed rates varied from 10 to 480 pounds per hour . In some tests , the influence of varying loads of sand grinding media on particle size reduction was studied . Batch grinding tests also were made for comparative purposes . Multiple- stage grinding gave better results than single - stage treatment when equivalent raw clay feed rates were used . In the best test made , a product containing about 80 percent minus 2 - micron esd material was obtained when grinding 60 pounds of raw clay per hour using a three - stage grinding circuit . Power consumption in the test was about 318 kilowatt -hours per ton of clay treated or 475 kilowatt - hours per ton of minus 2 - micron esd material produced .

Jan 1, 1963

By P. R. Tisot

This report discusses the waxes made from shale-oil wax distillate, a specific fraction obtained- from crude shale oil. The plate wax crystals Were exceptionally well suited to solvent extraction. Methyl ethyl ketone was the preferred dewaxing solvent.' The quantity of wax recovered at 32°F was 18.8 percent of the wax distillate, or 6.6 percent of the crude shale oil. The laboratory batch processes used for separating the wax from the distillate and subsequent refining were based .upon conventional petroleum methods. Three grades of shale-oil waxes were made and designated as crude, semirefined, and fully refined. The solvent-extracted wax consisted mainly of paraffin and olefin hydrocarbons. The physical Properties of the fully refined shale-oil wax were the same as er corresponded closely to those of Billy refined petroleum paraffin wax. Inasmuch as the crude and semirefined shale-oil waxes can be separated and refined in much the same manner as petroleum waxes, the cest of manufacture should be about equal to that for making petroleum paraffin wax. The cast of making a fully refined shale oil wax will be somewhat greater than for making .a fully refined petroleum paraffin, due to the loss of the oleofinic material from the shale-oil wax by acid treatment and the increased quantity of acid required for its removal. An analytical method for the determination of wax in shale-oil dietillates, a list of the physical properties that wore determined for the waxes, and the method for testing those properties are given in the appendix to this report

Jan 1, 1950

By Nicholas Kyriazi, John P. Shubilla

A joint effort by the U.S. Bureau of Mines (USBM) and the US. Mine Safety and Health Administration (MSHA) was undertaken to determine how well self-contained self-rescuers (SCSR's), deployed in accordance with Federal regulations (30 CFR 75.1714), held up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSR's in the fourth phase of testing from 1989 to 1993. The SCSRYs were tested on human subjects and on a breathing and metabolic simulator (BMS). These results indicate that most of the apparatus, if they pass their inspection criteria, perform as expected except units with manufacturing defects. However, when the apparatus are carried in and out of the mine daily and stored at the working section, they may suffer abuse. Physical signs of abuse, unless extremely obvious, are frequently not detected by the miners or mine operators. In addition, some apparatus collected for this study had not been returned to the manufacturer in a recall effort for correction of a manufacturing defect. In both cases, the apparatus would have presented problems in emergency use. Recommendations include improved training in inspection procedures and better enforcement of recall notices.

Jan 1, 1994

By J. H. East

"INTRODUCTION .Very little information regarding coal mining in Spain has been published in the American technical press, and few people realize the extent of this industry or the conditions under which coal is mined. The information in this publication was collected in 1945 and consists of personal observations in Spain, statistics, and other data of a, general nature obtained from official sources.Spain produces bituminous coal, lignite and anthracite, but the total tonnage mined is less than the national requirements. Before the war, an appreciable tonnages coal was imported from Great Britain under the Anglo-Spanish treaty, which rebated import duties and effectually prevented competition from any other foreign source. The war stopped the major part of the important of British coal and caused rapid expansion of the domestic sources, but this was not sufficient to supply the industrial demand. Coal that formerly was not acceptable to industry because of quality is now mined and marketed. The Government, allocates the better-grade bituininous coal to the various industries in accordance with the national importance of the work in which they are engaged; for example, the railroads are allotted 100 percent of their requirements, but cement companies can obtain only 25 percent.The Government offered to inducements to increase the production of coal of any class, but the larger part of the increased tonnage obtained was in inferior grades; as a result, the lignite production was taxed, while a bonus was paid for bituminous-coal production in excess of the 1942 tonnage.The anthracite and bituminous-coal areas were severely damaged during the Civil War and many experienced miners migrated to the lignite mines in eastern Spain. This has resulted in an acute shortage, particularly the Province of Oviedo where the most important bituminous-coal deposits are located."

Jan 1, 1947

By R. T. Artz

Disposal of sewage is an important part of mine sanitation. Improper... handling and.disposing of sewagerare conducive to the spread of disease and often add foul and nauseating odors to the mine air. The diseases spread by unsafe methods of disposing of waste in mines are typhoid fever, cholera, amebic dysentery, hookworm, and other intestinal diseases due to parasites. Sanitary toilet facilities, with a good sewage-disposal system, each maintained in good order at all times, should help to prevent the spread of diseases transmitted by intestinal body wastos. The metal and nonmetal-mining industries have recognized the impor-dma tance and need for disposing sewage properly; accordingly, facilities of some sort are installed and need today in most large mines. The coal-mining industry has given little thought to the disposal of sewage underground; however, in most mines of the anthracite industry, the inflow of large vol- unes of highly acid mine water and the extensive drainage system required to remove this water provide a natural means for disposing of sewage.

Dec 1, 1946

By F. P. Haver

The Bureau of Mines is developing a leach-electrolysis procedure to produce Special High Grade (SHG) zinc from sulfide concentrate without the generation of sulfur oxide gases. Chlorine-oxygen leaching of the concentrate yields zinc chloride (ZnCI2) which, after purification, is electrolyzed in a fused-salt cell to obtain molten zinc metal and chlorine gas for recycle. This paper describes a laboratory-scale investigation made to develop a procedure for electrowinning zinc metal from ZnC12. Zinc chloride by itself is not a suitable electrolyte because it fumes badly above its melting point and is a poor conductor of electricity. Other salts therefore must be added to prevent fuming and improve the conductivity. Optimum results were obtained with a KC1-LiCl-ZnCl2 bath at 500° C, using a current density of 5 amp/in2 and an electrode spacing of 0.5 inch. Under these conditions, SHG zinc was produced at a current efficiency of 94.3 pct and an energy requirement of 1.16 kwhr/lb. Fused-salt electrowinning eliminates the need to handle and melt cathodes and increases the production of metal per unit cell volume through the use of higher current densities than are possible with aqueous electrolysis.

Jan 1, 1976

By J. W. Walkiewicz

The Bureau of Mines investigated alloys containing lanthanum (La), praseodymium (Pr), neodymium (Nd), cobalt (Co), copper (Cu), iron (Fe), and magnesium (4g) as possible components of a permanent magnet mate¬rial utilizing a cerium-free synthetic mischmetal (M) as a substitute for scarce samarium (Sm) metal. Magnets containing M-Co-Cu-Mg and M-Co-Cu-Fe-Mg were fabricated by powder metallurgy techniques and evaluated. A synthetic mischmetal (M20) containing 20 pct La, 60 Pr, and 20 Nd yielded the best overall magnetic properties. The M20-Co-Cu-Mg alloys had energy products as high as 13.2 MGOe, remanences as high as 7.89 kG, normal coercivities as high as 6.26 kOe, and intrinsic coercivities as high as 13.4 kOe. The best value of intrinsic coercivity, 22.9 kOe, was obtained with an M-Co-Cu-Mg magnet in which the synthetic misch¬metal contained 30 pct La, 50 Pr, and 20 Nd. These values compare favorably with those of the Sm-Co magnets fabricated and measured at the Bureau's Reno Research Center, which had energy product of 15.1 MGOe, remanence of 7.8 kG, normal coercivity of 7.5 kOe, and intrinsic coercivity of 27.4 kOe. Iron substitution for part of the cobalt resulted in a decrease of magnetic properties, although several percent iron can be added before a drastic loss of magnetic properties occurs.

Jan 1, 1983