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By D. Montagna

The Kroll-Betterton process for debismuthizing lead is based on adding calcium and magnesium to impure molten bullion to form solid Ca-Mg-Bi inter-metallic compounds that float on the surface as drosses. Present practice in industry is to hand-skim off these drosses, often followed by hydraulic pressing to squeeze out some of the entrapped liquid lead. In an effort to develop an improved technique, the use of an argon-shrouded dipping centrifuge to perform the required phase separation was investigated. Centrifugation experiments demonstrated that the bismuth content of an impure bullion could be lowered from an initial 0.5 percent down to 0.03 percent with a lead recovery of 90 percent, which is comparable to lead recovery after hand skimming of drosses in commercial lead-debismuthizing operations. Centrifugation provides better control in removing drosses, faster operation with less oxidation and relatively little fuming, and recovery of a lead bullion that approaches commercial specifications.

Jan 1, 1972

By D. L. Nussear, W. E. Wallace, N. N. Clark, M. Gautam, G. Hong-Guang

"Results from a study directed towards identifying and measuring the mutagenicity of diesel exhaust particulate matter involved in mining exposures, especially those which may synergistically affect genotoxic hazard, are presented in this paper. Particulate matter emissions from a diesel engine, representative of the ones found in underground mines, were sampled and assayed to determine the genotoxic potential as a function of engine operating conditions. Diesel exhaust was diluted in a multi-tube mini-dilution tunnel and the particulate matter was collected on 70 mm fluorocarbon coated glass fiber filters as well as on 8"" x 10"" hi-volume filters. A six mode steady state duty cycle was used to relate engine operating conditions to the mutagenicity potential.Protocols developed for using a primary component of pulmonary surfactant as a medium for collecting and applying respirable particulate material to cells for mutagenicity testing offer a true representation of in-vivo delivery of such respired aerosols to pulmonary cells and the genetic material within . The surfactant dispersion technique is discussed in this paper. Methods have been developed to sample and assay the diesel soot and diesel soot/mineral dust complexes which would not compromise the surface and physical properties of the particulate material."

Nov 1, 1995

By B. J. Scheiner

As part of the goal to maximize minerals and metals recovery from primary domestic resources, design factors associated with minimizing current leakage in bipolar cell configurations were studied by the Bureau of Mines as a means of improving the efficiency of bipolar e1ectrooxidation cells. Initial studies that were conducted in a small bipolar cell operating at 140 to 145 volts and 15.4 amp indicated how design factors could be employed to minimize cur-rent leakage around adjacent electrodes during cell operation. Based on these results, a 40-electrode, 108-kva prototype of an industrial-sized cell was constructed and tested for extracting metal values from offgrade molybdenite concentrates. The feasibility of recovering molybdenum and rhenium from the oxidized pulp also was determined. Feed to the process sequence consisted of flotation concentrates containing 16 to 35 pet Mo as molybdenite and 6 to 15 pct Cu. E1ectrooxidation in the prototype cell resulted in 84 to 97 pct Mo and Re extraction with a corresponding energy consumption of 9 to 13 kwhr/1b Mo extracted.

Jan 1, 1979

By J. J. Forbes

The Coal Mine Inspection Branch of the Health and Safety Division, Bureau of Mines, was established to carry out the provisions in Public Law 49, 77th Congress, H. R. 2082, approved May 7, 1941. The series of major disasters that beset the coal-mining industry in 1940 aroused public interest in mine-safety measures, and the act 18 the direct result of this rekindled interest. Under the provisions of the act, the Secretary of the Interior, acting through the Federal Bureau of Mines, is authorized and empowered to make, or cause to be made, annual or necessary inspections and investigations in coal mines, the products of which regularly enter commerce or the operations of which substantially affect commerce. The principal functions of the Federal coal-mine inspectors are to determine the causes of accidents and occupational diseases in coal mines and then endeavor to eliminate or ameliorate them (1) by revealing, through personal conferences with mine personnel, correspondence, and published reports, the unhealthful and unsafe conditions and practices existing in the mines and (2) by recommending practical means for correcting the conditions observed. The act does not provide any enforcement powers, and therefore compliance with the inspectors' recommendations is not mandatory; it does give Federal coal-mine inspectors the right to enter coal mines for inspection purposes.

Jan 1, 1951

By Robert F. Holub

The U.S. Bureau of Mines (USBM) has tested a personal dosimeter for measuring radon decay products that is manufactured by Tom Scurry Associates. The tests were made to determine the accuracy of the dosimeter system for record keeping of radiation exposures to radon decay products encountered in mining. The radioactivity-detecting head is based on a design developed by the USBM, and the associated air pump was developed by the manufacturer. The dosimeter system was tested in the USBM radon chamber. The detecting head uses CaF:Dy thermoluminescent phosphors and is mounted on a self-regulating air pump. Batteries supply power sufficient for an 8-h shift. The dosimeter system is worn on the miner's belt. Dosimeter calibration tests were performed by the USBM. In addition, the pumps were tested and evaluated under continuous flow conditions. The results of these tests indicate that the Tom Scurry Associates Model DOSI600 dosimeter is suitable for general use in mines where record keeping for natural radiation exposure is required.

Jan 1, 1995

By Ralph B. Adair

The Bureau of Mines conducted laboratory and continuous pilot plant flotation tests to determine the feasibility of recovering commercial-grade mica from an Alabama graphitic-mica schist. Preconcentration of the ground ore on a Humphrey's spiral was employed to reject the heavy minerals and part of the quartz in a product virtually free of mica. The acid-cationic mica flotation process recovered over 89 percent of the mica in a product containing 98.7 percent mica. Grinding of the mica concentrate in a fluid energy mill produced a product with a bulk density of 12 lb per cubic foot.

Jan 1, 1969

By Michael Rieber

Rail cars are referred to as "yellow-balled" when they are sufficiently old or damaged to preclude their efficient operation on long-haul or main line routes. For most coal carrying railroads, their alternative value is salvage. This, however, does not necessarily preclude their effective use, on a limited basis, by small mines located near existing trackage. Because of age, the sizes of these hopper and gondola cars ace currently 50 and 70 tons rather than the 100 tons commonly built at the present time. As a gathering system, yellow-ball rail could provide an alternative, particularly in Kentucky, western Pennsylvania and west Virginia, to coal trucks, conveyor belts and pneumatic pipelines [4, p.17], belts and pneumatic pipelines. Rail service of this type provides a limited alternative to track abondonment, a possible financial return to a railbank [3], a direct contribution to service demand on main lines, and a means by which many small eastern coal mines could retain or regain competitive viability [4]. In terms of energy efficiency, compared to trucking coal, the total direct energy impact (fuel) of yellow-ball rail can be expected to range from 280-990 Btu/ton-mile while that for trucks ranges from 1850-3120 Btu/ton-mile [2].

Jan 1, 1977

By Harry Freund, Kenneth H. Hammill, Francis C. Bissonnette

"Gallic acid is a sensitive, stable, colorimetric reagent for the determination of tantalum in the range of 2 to 40 µ g.Ta/ml. The method consists of the fusion of tantalum oxide with potassium pyrosulfate and solution of the cooled melt in saturated ammonium oxalate, followed by development of a yellow complex with an ethanolic solution of gallic acid. The tantalum-gallic acid complex absorbs over a broad region in the blue and near ultraviolet. Adverse effects due to interfering ions and solution conditions, such as oxalate concentration and pH, can be minimized by a suitable choice of wave length.by a suitable choice of wave length.A new and sensitive colorimetric method is provided that has been used successfully at the Northwest Electrodevelopment Laboratory of the Federal Bureau of Mines for determining minor amounts of tantalum.INTRODUCTIONThe development of corrosion-resistant alloys at the Northwest Electrodevelopment Laboratory prompted a review of the analytical chemistry of columbium (niobium) and tantahnn. Not only are these elements difficult to determine in small amounts, but tantalum especially lacks both sensitive and characteristic color reactions. Various phenolic compounds have been suggested as colorimetric reagents for tantalum, Quentin and Wagner (10, p. 24B) 1/ recommend the use of tannin. The use of pyrogallol was suggested originally by Krivoshlykov (6, pp. 59-60), whose method recently has been subject to a number of modifications (3, pp. 249-254; 5, pp. 1340-1344; 1, pp. 1803-18oi; 4, pp. 345-350). The yellow coloration produced by pyrocatechol in an oxalate solution containing tantalum may also be used to estimate tantalum ( 11, pp, ll-1-4-148) . The use of hydrogen peroxide has been recommended also (7, pp. 164-165; 9, pp. 926-931).Aside from a lack of specificity and sensitivity, the major failing of phenolic reagents is their susceptibility to air oxidation. The oxidation products are highly colored and absorb in the same spectral region as the tantalum complex. Holding reductants are not completely satisfactory in minimizing this effect. Increasing the acidity, while retarding the oxidation, has an adverse effect on the tantalum sensitivity."

Sep 1, 1956

By C. J. Thompson

Two sulfur compounds--the 2,2,5-trimethyl- and the 2,2,5,5-tetramethyl derivatives of thiacyclopentane--were identified in Wilmington, Calif., crude oil, using microdesulfurization and gas-liquid chromtography techniques.

Jan 1, 1963

By T. J. Ballard

The Track Rock corundum mine was among the numerous corundum deposits investigated during the war by the Bureau of Mines in an effort to develop domestic reserves of that critical mineral. In the investigation of this property 562 feet of trenches were excavated and a l25-foot adit was reopened for the purpose of locating veins to of corundum which had been previously reported to occur in that locality. Only very minor amounts of corundum were disclosed in both the surface workings and the adit. The project was begun in May 1943 and completed in November 1943.

Jan 1, 1948

By J. R. Nettle

The electrodeposition characteristics of seven binary alloys of titanium have been investigated. The object of the electrorefining experiments with an alloy was to determine the efficiency of titanium separation from individual alloying elements under established conditions. Reported results are only indicative. It is conceivable that numerous duplications of tests might give average maximums that would vary from those noted in this report; however, in the few tests that were repeated, the magnitude of transfer of the alloying elements was of the same order. The results detailed herein are for a given set of conditions. Many combinations of operating variables are possible, and the results achieved under different conditions probably would differ from those reported.

Jan 1, 1958

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 E. P. Youngman

The mining law now in force in Finland is the Imperial Russian Ukase of 1883, promulgated November 12, 1883, by Czar Alexander III, with the sanc- tion and permission of the Finnish Estates. This law repealed prior legisla- tion, as follows: Crdinance of liay 25, 1857, concerning the appropriation of ores and minerals; as wall as the right to remove and utilize them; proclama- tion of January 20, 1868, amending, the ordinance of May 25, 1857; proclama- tion of October 3, 1621, concerning the appropriation of precious metals; and the proclamation of October 30, 1878, concerning prospecting for gold, etc., in Finnish Lapland. A proposal for a new mining lar is still being considered by the Finnish Diet. This new law, if and when promulgated, will differ only slightly from the law of 1683 but will be drafted in more modern language."

Jun 1, 1932

By Eliot J. White

The physical properties and clay mineral content of the major oil-producing formations in the Powder River Basin of Wyoming were determined by analyses of cores from 100 wells. Interrelationships were established among permeability, restored water saturation, clay content, and bulk swelling capacity of the crushed sample and used to estimate the susceptibility of the formations to water damage. The ratio of water permeability to gas permeability (kw/ki) offers a convenient scale for semiquantitatively estimating the water sensitivity of sands. The irreducible water saturation was also found to have a similar relationship to the clay mineral content and the water sensitivity of the sands. The average relation of water permeability to gas permeability is different for each sand, as shown by the curves, and the relative positions of the curves indicate the degree of water sensitivity of each sand from which the susceptibility to water damage may be estimated. How accurately these estimates show formation behavior under field operations will not be known until studies of field performance can be made. The water permeabilities of the Muddy, Minnelusa, and Tensleep sands average about the same as the gas permeabilities, and these sands are classified as insensitive. The water permeabilities of the Sussex and Shannon sands, at the other extreme, are much less than the gas permabilities [when average ki is 30 millidarcys (md), kw is 6.1 md], and these sands are classified as highly water sensitive. The sensitivities of the five other sands are between these extremes.

Jan 1, 1962

By Alla D. Mah

Energies of combustion of vanadium nitride (VN) and vanadium carbide (VC) were measured. Correcting to vanadium tetroxide (V204) as the final state, the heats of combustion were ?H298.15=-118,700±100 cal/mole of vanadium nitride and ?H298.15=-240,270±360 cal/mole of vanadium carbide. With vanadium pentoxide (V205) as the final state, the heats of combustion were ?H298.15= -133.440±100 cal/mole of vanadium nitride and ?H298.15=-255,020±360 cal/mole of vanadium carbide. Combining these results with vanadium oxide data, the heats of formation obtained were ?298.15=-51,880±200 cal/mole of vanadium nitride and ?H298.15=-24,350±400 cal/mole of vanadium carbide. Heats and free energies of formation of vanadium nitride and carbide were calculated to 2,000° K.

Jan 1, 1963

By L. B. Pankratz

Heat contents, measured above 298.15° K, and derived entropy increments are presented in tabular and equation form for the two crystalline forms of zinc sulfide (sphalerite and wurtzite) and for four solid solutions of iron and zinc sulfides having the compositions Zno.,,6Fe0.302S, Zno.750Fe0.250S, Zno.650Fe0.3505, and Zno.498Feo.502S.

Jan 1, 1965

By Paul M. Tyler

The colony of French Guiana ( or Cayenne ) is administered by a governor , assisted by a privy council of five members . A council - general of 16 members is elected by French citizens resident in Guiana, and the colony is represented 3 in the French parliament by one deputy . The area is about 34,740 square miles . French Guiana is the largest gold producer of the French colonies , producing nearly $ 1,000,000 worth annually . Considerable prospecting has been done on the bauxite deposits , which are extensive . Copper , iron , lead , and 4 mercury deposits are also reported . In 1931 , 10,000 prospectors for gold were reported as working . The French Government is taking an active interest and has sent a committee of mining experts to explore the region ; no permits are to be issued to individual prospectors while the committee is in the colony . Plans for development of mining industry include consideration of 4,500 convicts and 2,500 natives already in the colony and available for labor .

Apr 1, 1933

By R. R. Sayers

There is probably no industry , trade , or art in which mercury is used but what has produced some cases of mercury poisoning . This is true of the mining and smelting of mercury , where the hazard has long been recognized . When the ore contains free mercury or the more soluble salts , and when the workings are underground and are poorly ventilated , cases occur , but there are a far greater number of cases among the employees about the reduction works . 3 In 1863 William V. Wells visited the mines at Almaden , * Spain , which were worked by convicts . He reported that the men at the furnaces suffered severely , being able to work only about one week out of four , when it was necessary to transfer them to places where the exposure was less . He states that "pale cadaverous faces and leaden eyes are consequences of even these short periods . " Mercury , like lead , when absorbed in small amounts at intervals , as daily, over an extended period of time will result in symptoms of poisoning . This is due to the fact that the mercury is eliminated from the body more slowly than it is absorbed . The frequency and severity of cases of mercury poisoning are far less with modern methods of mining and recovery of the metal than formerly . However , further reduction is possible and much can be done by both the workmen and the operators by following the proper precautionary measures , some of which are described in this chapter .

May 1, 1922

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of El Salvador has been prepared from the best available information in Washington , but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State . Under the terms of the Code of Commerce ( arts . 12ff . ) , foreigners living in El Salvador can engage in business on the same terms as nationals . This involves ( = $434.00 ) - except for those with a working capital , of less than a thousand pesos inscription in the merchants ' register , which can be refused only in case of manifest disability of a permanent nature .

Sep 1, 1930

By D. R. Dolinar, J. Pablic, D. C. Oyler, T. P. Mucho

At a mine in central PA, high horizontal stresses have caused long running roof falls resulting in hazardous conditions for the miners and the premature abandonment of panels. Because of these conditions, the mine requested assistance of the National Institute for Occupational Safety and Health (NIOSH) in utilizing the 'advance and relieve method to mitigate the affects of horizontal stress on the mine roof. "Advance and relieve" mining involves the removal of a pillar or a portion of a pillar during development, thereby creating a cave along one side of the panel. Following cave development, the horizontal stress is relieved over the workings adjacent to the cave in the active panel. The mine has used this system in three panels with a significant reduction in stress damage and no large roof falls.