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By K. K. Kershner

Sulfide ore concentrates containing cobalt, nickel, copper, lead, and iron were salt roasted and leached on a laboratory scale. More than 95 percent of the cobalt, nickel, and copper was recovered. Heating patterns for salt roasting different concentrates were established. More cobalt, nickel, and copper were recovered from a bulk concentrate composed of a mixture of copper concentrate and iron concentrate. This mixture corresponded roughly with the mixture of these materials in stockpiles in southeastern Missouri. A temperature range of 375° to 400° C. was best for salt roasting. Metal chlorides were leached at a pH of 1 from chloridized charges of concentrates, Although the amounts of cobalt, nickel, and copper extracted were high, the amount of iron dissolved simultaneously interfered with subsequent separation and recovery of these metals. The amount of dissolved iron was reduced substantially by steam treating chloridized charges of bulk concentrate at 300° C. In this way, the ratios of cobalt, nickel, and copper to iron in leach liquors permitted satisfactory separation and recovery of these metals. INTRODUCTION The Federal Bureau of Mines is experimenting with chloridizing reactions.4 5 6 7/ Salt roasting of sulfide ores and concentrates, or their calcines, to form metal chlorides has certain advantages. Chlorides of

Jan 1, 1961

By H. B. Brunot

A complete list of permissible mine equipment, tested and approved by the Bureau of Mines previous to January 1, 1947, was published as Information Circular 7432.2/ A list of permissible mine equipment tested and approved by the Bureau of Mines during the calendar years 1947, 1948, and 1949 was published as Information Circular 7569. The present list supplements Information Circulars 7432 and 7569 and includes all of 'the equipment approved during the calendar year 1950. Information Circular 7465, which included a list of permissible mine equipment tested and approved by the Bureau of Mines during the calendar year 1947 therefore is superseded.

Jan 1, 1951

By S. A. Matthes

This Bureau of Mines report describes analysis of a copper slag for 13 elements from a single sample solution by flame atomic absorption spectroscopy. Samples are dissolved with 7 ml of an HC1-HF-HN03 (3:1.5:2) mixture in heated plastic pressure vessels. A 1.5-pct boric acid solution is added to dissolve precipitated fluorides and to reduce matrix effects that interfere with atomic absorption analysis. Preparation time is less than 1 hour per batch of 10 samples. Total analysis time is less than 6 person-hours for 130 determinations with an average relative standard deviation of 1.83 pct for the 13 elements. Simple acid standards were used for all determinations. Values obtained by this method are in excellent agreement with values obtained by slower, more costly procedures.

Jan 1, 1980

By John R. Benham

The West Pioneer RARE II study area, No. 1-006 (fig. 1), has Figure 1.--NEAR HERE a high molybdenum resource potential. Two molybdenum-bearing areas are being explored by Utah International and by Cyprus-Moly Corp, Inc. using geophysical exploration and diamond core drilling. The study area also contains potential resources of gold and silver at six prospects: the Bear Paw (Ibex), Black Bear, Coeur d'Alene, Franklin No. 1, Martin, and Maynard. In addition, the Black Rear and the Martin contain possible copper, lead, and molybdenum resources. Most of the workings are caved.

Jan 1, 1981

By H. G. Iverson

The effects of adding boron and boron plus carbon to electrorefined vanadium were evaluated with respect to mechanical properties at low temperatures and response to heat treatment. Grain size was significantly decreased with the addition of 0.05 percent boron, the decreases ranging from 30 percent at 800° C to 75 percent at 1,100° C. Increasing the boron content resulted in only a small increase in strength at room temperature, but at 77° K, boron contents of 0.005 to 0.076 percent increased the yield strength of vanadium over 50 percent, from 70,000 psi to 110,000 psi. When boron and carbon were present together, the individual grain-refining effects obtained with either element were retained. Approximately a twofold increase in strength was obtained by age-hardening the alloys containing both boron and carbon. Alloys with only boron additions did not age-harden.

Jan 1, 1968

By L. B. Berger, S. J. Pearce

One phase of Bureau of Mines' work in health and safety is promotion of the use of safe, satisfactory, and reliable respiratory protective. devices. To insure that such devices will be available, the Bureau has established schedules of minimum requirements for self-contained breathing apparatus, gas masks, supplied-air respirators. (hose masks, air-line respirators, and abrasive blasting helmets, hoods, or masks), dispersoid (dust, fume, and mist) respirators, and nonemergency gas respirators (chemical cartridge respirators). Approval tests of self-contained breathing apparatus are conducted by the Safety Branch; approval tests of other types of respiratory protective equipment are conducted by the Health Branch. Both branches are in the Health and Safety Division.

Jun 1, 1950

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1963 to June 30, 1964 are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1964; in general; the research reported in these publications antedates the report period. Part 3 describes a short-term investigation into safety problems associated with shipping of molten sulfur; this investigation is not at present destined for publication elsewhere.

Jan 1, 1965

Develop a means of determining both the fill level of material in an ore pass or bin and the location of bridging material causing a blockage.

Jan 1, 2000

By N. S. Dalal, X. Shi

"Electron spin resonance measurements provide evidence for the formation of long-lived Cr(V) intermediates in the reduction of Cr(Vl) by glutathione redtuctase in the presence of NADPH and for the hydroxyl radical formation during the glutathione reductase catalyzed reduction of Cr(Vl). Hydrogen peroxide suppresses Cr(V) and enhances the formation of hydroxyl radicals. Thus Cr(V) intermediates catalyze generation of hydroxyl radicals from hydrogen peroxide through a Fenton-like reaction. Thus the mechanism of Cr(VI) toxicity might involve the interaction between macromolecules and the hydroxyl radicals.C(Vl) compounds have been found to exert serious toxic and carcinogenic effects on humans and animals (1-3). In contrast, most Cr(III) compounds are relatively nontoxic, noncarcinogenic, and nonmutagenic (1,4). Cr(VI) and Cr(III) oxidation states are different in their metabolic pathways: Cr(VI) , ions are rapidly transported across cellular membrane (1,4,5), while Cr[III) moieties do not easily penetrate cells and are not oxidized by cellular constituents (!). Since it is known that the reduction of Cr(VI) ion is required for its reaction with DNA (1), the molecular mechanisms for the intracellular Cr(Vl) reduction has been the focus of current studies but the details are still not understood.Earlier studies on the mechanism of Cr(Vl) reduction include those on the reduction of Cr(VIJ by glutathione (GSH) .0,6-8), ascorbic acid (9), glucose (10), lactose (IO), galacturonic acid (11), microsome (12), and mitochondrial electron transport chain complexes (13). These studies have shown that the Cr(VI) reduction involves the formation of Cr(V)-containing species which are often considered to be the toxic form of chromium. Thus far, however, no information is· available on the subsequent fate of those biologically formed Cr(V) species, in particular employing well defined biochemical systems. In this context, we report here our investigations of the reduction of Cr(VI) by glutathione reductase (GSSG-R). This enzyme was selected because it is ubiquitously present in cellular systems and it has been postulated to be involved in the Cr(VI) reduction (14-17) but the underlying mechanism has not been clarified. We find that the reduction proces·s involves not only Cr(V) but also ·OH radicals. We further investigate the reactivity of Cr(V) and find that it catalyzes generation of OH radical from H2O 2 through a Fenton-like reaction. The role of ·OH in Cr(VI) carcinogenicity is suggested from this study."

Jan 1, 1989

By J. Baicker

A two-inch diameter probe containing an intrinsic germanium detector, a canister-type solid cryogen cooling system, cooled FET preamplifier, linear amplifier, high voltage supply, analog-digital converter, microprocessor, buffer memory, bidirectional cable link, and all power supplies has been designed, assembled and tested. A surface support vehicle was designed, built and outfitted. A mini-computer system was constructed and preliminary software developed and tested. A special handling system for a Cf-252 neutron source was designed and has been ordered. The entire system (less the neutron source) is ready for its first field tests. Lab description of the system is presented.

Jan 1, 1978

By Jeffrey Shawn Peterson

Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response, the National Institute for Occupational Safety and Health (NIOSH) conducts research to reduce the noise emission of various underground coal mining equipment, an example of which is a roof bolting machine (RBM). After the removal of coal or rock, the remaining strata may be subject to fall, either from overhead (the roof) or from the side (the rib). One method used in underground coal-mines to prevent failures requires the installation of roof bolts. The roof bolting machine operator trams the machine to the required location, drills a hole into the strata, and then installs a roof bolt, supporting the roof or the rib, as the case may be. Field studies support the premise that, on average, drilling noise is the loudest noise that a roof bolting machine operator would be exposed to and contributes significantly to the operators? noise exposure. NIOSH has determined that the drill steel radiates a significant amount of noise during drilling. NIOSH is developing bit and chuck isolators to reduce vibration, and thus noise radiation of the drill steel, with the longer-term goal of reducing roof bolting machine operator noise exposure. Laboratory testing has shown that operator ear sound pressure levels may be reduced by 3 to 7 dB(A), depending upon the test configuration and drilling media.

Jan 1, 2009

By Oliver Q. Leone

Three electrorefining cells were designed to investigate various factors associated with the electrorefining of reject - grade titanium sponge . Operation of the cells provided information on cell design as well as on how design and operating variables affected the quality of the titanium product . A sodium chloride - titanium chloride electrolyte was used , and the electrolyte chambers had capacities ranging from 400 to 3,500 pounds of molten salt . Major factors investigated were electrolyte composition , temperature and useful life , effect of various cathode shapes and materials of construction , methods for removing cathode deposits , effect of current density and cell potential , and the mechanics of deposit growth and crystal morphology . One of the cells was in intermittent operation over a 4 - year period and produced 2 tons of refined titanium . A product with a hardness of 80 or less Bhn (Brinell hardness number ) was consistently and easily obtained . Some metal with a hardness of less than 60 Bhn was produced . In one of the cells in which the electrolyte was held at operating temperature with an internal heater an ac input of 25 kw maintained 3,500 pounds of electrolyte at 850 ° C , but with an external heater 35 kw was required to maintain 400 pounds at 850° C.

Jan 1, 1964

By David J. Kusler

This report describes a rapid, reliable, and relatively simple method developed by the Bureau of Mines Pyrometallurgy Laboratory at Bruceton, Pa., for determining lime (calcium oxide) and magnesia (magnesium oxide) in various materials containing these constituents in greater than trace amounts. Optionally, titania (titanium dioxide) may be determined for the same sample. The accuracy of the method, suitable for most purposes, is shown by comparing the Bureau results with those obtained by accepted procedures. The method has been applied satisfactorily to the routine analysis of blast-furnace slags, for which purpose it was primarily developed, and to other calcareous compositions. In the Pyrometallurgy Laboratory it has replaced the standard methods previously used to determine lime and magnesia, and has been in general use by that laboratory for the past several years. The analysis time, generally under 3 hours, is considerably less than required by standard methods.

Jan 1, 1960

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1963 to June 30, 1964 are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1964; in general, the research reported in these publications antedates the report period. Part 3 describes a short-term investigation into safety problems associated with shipping of molten sulfur; this investigation is not at present destined for publication elsewhere.

Jan 1, 1965

By R. R. Wells

This report summarizes the results of laboratory investigations by the Alaska Mining Experiment Station, Juneau, to determine the practicability of treating cinnabar-stibnite ore by bulk flotation and controlled-atmosphere roasting of the concentrate. Ore from the Red Devil mine near Sleetmute, Alaska, was selected for testing; it is typical of ores widely distributed throughout the Kuskokwim River Basin. The material, consisting of stibnite and cinnabar in ankerite, dolomite, and quartz, assayed 1.55 percent Hg and 2.87 percent Sb. Continuous treatment of the ore in a laboratory flotation circuit recovered 95.7 percent of the mercury and 82.6 percent of the antimony in a concentrate that assayed 20.4 percent Hg and 34.6 percent Sb.

Jan 1, 1958

By Ronald A. Vary

This paper is one of a series prepared by the United States Bureau of Mines dealing with milling methods and costs. In view of the current revival of interest in gold mining, information dealing with practices and costs in the development of gold properties is apropos. Milling practice at a small gold property in the prospect stage is described where, with a small outlay for plant and equipment, development has been carried on for about 20 months on the proceeds of the mill operation with little additional expenditure. The paper shows about what may be expected as to costs at a small property operated under northern climatic conditions and with rigid economy throughout the plant.

Jan 1, 1931

By Constantine C. Popoff

Several limestone deposits in western Washington were examined by the Bureau of Mines in 1946. This report presents data obtained from the investigation of limestone deposits in the vicinity of Arlington, Snohomish County, Wash. The work consisted of surface surveys and sampling. Samples were taken where complete, or nearly complete, sections of limestone were exposed or where individual beds were exposed at a number of separate .localities. Areas were cleaned by blasting prior to sampling. Channel samples were cut where practical; otherwise chip samples taken. Twenty-one samples were taken. The locations of the samples and the analyses are shown on maps accompanying this report.

Jan 1, 1949

By H. P. LeVan

Research was conducted to examine the feasibility of extracting manganese from Georgia umber ore by a three-stage continuous sulfuric acid-ferrous sulfate pickle liquor leaching process. A continuous cyclic process for treating the umber was operated successfully, using a synthetic solution simulating a ferrous sulfate fortified anolyte solution discharged from a manganese electrolytic cell as the leaching medium. Leaching efficiency based on removal of the manganese from the ore ranged from 83 to 89 percent for all systems tested.

Jan 1, 1965

By Charles E. Munroe

At the outset of the war the uncontrolled production and possession of explosives obviously became a serious menace to the safety of persons and property and the successful conduct of military opera- tions. Even in the years immediately preceding the entrance of the United States into the Great War explosives were employed in attempts to wreck munitions plants as at Eddystone, Pa., or to inter- rupt transportation and conveyance by demolition of munition-laden cars as at Black Tom Island, N. Y., or by attacks on ships, bridges, and viaducts. Outrages with explosives, such as that which Holt inflicted on the Senate reception room, United States Capitol, were not infrequent, and often caused serious loss of life and injury to persons as well as destruction of property. The regular manufacturers of explosives were keenly alive to this menace and early took such steps as lay within their power to meet it as is shown by the following letter:

Jan 1, 1921

By G. W. Birge

Carbonizing properties of the principal coalbeds of Elk, Clarion, Jefferson, Clearfield, and Centre Counties, Pa,, are described in this Bureau of Mines report, Twenty-six samples, representing the Upper Freeport, Lower Freeport, Upper Kittanning, Middle Kittanning, Lower Kittanning, and Brookville beds, were carbonized by the Bureau of Mines--American Gas Association (BM-AM) method, and yields of products and physical properties of cokes were determined. Expansion or contraction of the majority of the samples was measured in the Bureau of Mines sole-heated oven. Chemical analyses, agglutinating values, and free-swelling indexes are given for all samples. In this area the coals generally are characterized by high sulfur and moderately high ash content, and their suitability for metallurgical use would depend largely upon satisfactory cleaning. The samples from Elk, Clarion, and Jefferson Counties were high-volatile A bituminous In rank, whereas, most samples from Clearfield County and all those from Centre County were of medium-volatile rank. Coals from Clarion County had dry, mineral- matter-free fixed-carbon contents ranging from 56.5 to 60.3 percent and were weakly coking. With the exception of two samples which contained excessive ash, the medium-volatile coals of Clearfield and Centre Counties were strongly coking and, as indicated by sole-oven expansion results, would require blending with lower rank coal to avoid oven damage.

Jan 1, 1963