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By Catherine C. Kilgore

The Bureau of Mines investigated the availability of lead and zinc from 104 domestic mines and deposits. Fourteen primary lead and fifty-three primary zinc operations with in situ demonstrated resources containing 27.3 million metric tons (t) of lead and 53 million t of zinc were subsequently evaluated. Potentially 17.5 million t of lead and 2.4 million t of byproduct zinc could be recovered from 14 primary lead operations. Economic evaluations performed in constant January 1982 dollars determined a long-run total cost per pound of recoverable commodity. Including a 15-pct discounted-cash-flow rate of return (DCFROR), 59 pct of primary lead was potentially available at or below $0.32 per pound of lead. Potentially 40 million t of zinc and 5.6 million t of byproduct lead could be recovered from 53 primary zinc operations. Ninety percent of the recoverable zinc is potentially available from currently nonproducing mines and deposits, and a weighted average of their long-run total costs was determined at $0.98 per pound of zinc. At a breakeven (0-pct) DCFROR, these non producing operations had a weighted average long-run total cost of $0.58 per pound of zinc. Sensitivity analyses illustrated that operations that recover byproducts were most sensitive to fluctuating metal prices, producing operations were more sensitive to increased smelter treatment charges, and nonproducing operations were impacted most by the DCFROR.

Jan 1, 1983

By Gregory J. Chekan

The Bureau of Mines, in an effort to improve planning and development in coal mining, is investigating strata interactions associated with mining of multiple coalbeds. Two common interactions that occur between adjacent coalbeds are subsidence and pillar load transfer. The study described involves underground observations and measurements conducted at two Pennsylvania mines, each affected by one of these interactions. At the mine affected by subsidence, measurements show that undermining had little effect on upper mine pillar stability, but had a more severe effect on the development and maintenance of entries. Roof-to-floor measurements recorded over four times more convergence in entries developed over gob as compared with entries developed over support pillars in the lower mine. At the mine affected by pillar load transfer, Initial in situ measurements have shown the existence of a pressure arch in the lower workings. Prior research has shown that arch interaction between two adjacent openings can create stress concentrations in the in-nerburden. Underground measurements and results obtained from both mine sites correlate with theoretical and photoelastic multiple-seam models, and eventually these field data will serve to refine model accuracy. Further study of multiple-seam interaction mechanisms will lead to improved mine planning, increased resource conservation, and a safer working environment.

Jan 1, 1986

No noticeable international economic recovery occurred during the first half of 1982. Industrial production continued to fall in the United States, Canada and Italy and to hold steady in France. Modest increases in production occurred in Japan, England and Germany, although some decline took place from March to April. The U.S. mining industry has been more severely affected by the world recession than the U.S. economy. This is not immediately obvious when comparing the U.S. mining industrial production index from 1981 to 1982, which decreased 8.5 percent, as compared to a 7.1 percent decline for total domestic industries. However, "mining" industry statistics in the U.S. national economic accounting system include petroleum and natural gas as well as minerals. When metal mining is isolated, the decrease in production from 1981 to 1982 is 19.3 percent. If metal mining production continues to perform at the same rate during the third and fourth quarters of 1982 as during the first half of the year, declines from 1981 levels will be quite severe. Aluminum will have declined 22 percent, copper 18 percent, iron ore 24 percent, lead 3 percent, steel 29 percent, titanium 2 percent and zinc 25 percent.

Jan 1, 1982

By Robert S. Schechter

This report describes the development and application of PHASEQ/FLOW, a geochemical flow simulator capable of describing the dynamic changes in chemical composition of an aqueous solution during flow in a permeable medium. The solution components can react through intraaqueous reactions, redox, precipitation, or dissolution. The assumption of local thermodynamic equilibrium ensures maximum generality with respect to the number of species and components possible; however, the fluid flow itself is limited to one-dimension. The report describes several applications: generic batch equilibria, flowing equilibria, uranium roll-front deposition, and roll-front leaching.

Jan 1, 1985

By Maria I. De Rosa

The Bureau of Mines performed experiments to determine concentrations of toxic gases and liquids, and smoke-particle diameters and diameter-concentrations evolved during degradation of PVC-derived brattice with and without nylon-woven fabrics, fiberglass, cotton, and jute brattices, and other mine materials. The samples were exposed in a 20-L chamber at temperatures of 1500 to 4500 C, with a chamber airflow of 10 L/min; 27.3 cm3/s of which was directed into a submicrometer-particle detector-analyzer. During the degradation of PVC-derived brattice, large concentrations of hydrogen chloride (TLV, 5 ppm; STEL, 100 ppm) evolved at a temperature as low as 2000 C. The minimum toxic load of 3.1 mg or 40 ppm in 50 L of dilution air, with O.l~g weight loss, may be reached at a mine face with 314,000 L of dilution air, at the 5th min, during which less than 1 kg of brattice undergoes combustion. Fiberglass, cotton, and jute brattices, pine wood dust, and coal dust showed small concentrations of carbon monoxide evolving during early stages of combustion. Hydrogen cyanide gas evolved from the PVC-derived, nylon-reinforced brattice; at a later stage of combustion, large concentrations pf carbon monoxide and dense smoke evolved from all PVC-derived brattices. Experiments to characterize smoke particles showed that marked differences exist in particle diameter-concentrations among the materials.

Jan 1, 1986

By Arnold M. Lansche

[Selenium and tellurium are rare elements in the earth's crust. Their scarcity and primary dependence of supply on copper and lead output are in consonance with the relatively small quantities consumed at 1964 level. Production depending on output of copper and lead creates a supply situation- which would appear to militate against development of large-scale usage of these elements. However, supplies have adequately met. demand in the past decade and can be increased substantially if warranted by new uses for either selenium or tellurium Ores of copper and lead re the principal sources of selenium and tellurium. Byproducts from the smelting and refining of copper and lead concentrates are incorporated in refinery anode slimes from which selenium and tellurium metal are recovered.]

Jan 1, 1967

By W. R. Moorehead

This paper, describing the mining methods and colt at the New Indria quicksilver mine, is one of a series of similar papers being prepared by the Bureau of Mines on various mines in the United States. The New Idria mine lies at an elevation of 3,500 to 4,200 feet in the Coast Range of San Benito County, Calif. The property is accessible by automobile stages from Gilroy or Hollister via Tres Pinos. Tres Pinos, 65 miles northwest of the mine, is the nearest railroad point.

Jan 1, 1931

By R. D. Currie

"INTRODUCTION Compressed air for operating coal-mining equipment is seldom considered in conjunction with modern methods and appliances. But the Jamison Coal & Coke Co. has proved the economy and efficacy of compressed air for this purpose at its Mine 8 near Farmington, 8 miles west of Fairmont, Marion County, W.. Va., and the mining industry as a whole concedes its superior safety in gassy or dusty coal mines.The uses for compressed air in coal mining are now generally associated with such equipment as coal punchers, chain-breast machines, and to a lesser extent the ""radialaxe"" type of mining machines.Electricity has rapidly superseded compressed air for power in coal mines during the past 20 years; and in the last few years the general, and often unwise, use of electricity at the face region has taken on added impetus through the widespread use of mechanical loading equipment.Some of the unfavorable results of this increased use of electricity are shown in the growing number of mine explosions and fires of electrical origin. In the past four years 59 explosions of this type took the lives of 672 men, or 74.8 per cent of the total number of deaths from explosions were due to explosions of electrical origin.3In 1926, an explosion in Mine 8 of the Jamison Co. killed 19 men. The exact source of ignition was not determined, although it was definitely decided that it was of electrical origin and probably was at an electric coal-cutting machine.Prior to this disaster the company had done some experimenting with compressed-air-driven mining machines, and its Mine 9 had been completely equipped with air-driven chain-breast machines; a few of these machines were also in use in Mine 8. The explosion, however, gave impetus to the adoption by this company of compressed air for operating face equipment. The chain-breast machines were as satisfactory as electric machines of the same type; but the trend in the industry was toward faster cutting machines, which required less physical exertion on the part of the operating crews. A track-mounted machine of the arcwall type was found to be suitable for the conditions and system of mining, so that one of these operated by compressed air was developed by the Jeffrey Manufacturing Co. working with the officials of the Jamison Co.The first of these machines was installed in the latter part of 1926 and additional machines were delivered from time to time, until at present there are nine of them in the mine. Necessary improvements have been made, with the result that a fast-cutting, easily handled, efficient, and safe mining machine has been developed for cutting the hard Pitts¬burgh bed coal of the Fairmont field."

Oct 1, 1932

By F. P. Haver

The Bureau of Mines has investigated the electrochemical reduction of lead chloride as a method for producing lead without the pollution problems associated with smelting. It was determined that high-purity metal (>99.9 pct Pb) could be obtained, using PbC12 prepared by ferric chloride leaching of galena concentrate: PbS + 2FeCl3?PbCl2 + 2FeC12 + S°. Optimum results in small-scale electrolytic tests were achieved with a bath consisting of 40 to 70 wt-pct PbCl2 dissolved in KC1-LiCl eutectic, an operating temperature of 450° C, a current density of 2.5 amp/in2, and an electrode spacing of 0.5 inch. In large-scale tests made to develop a cell design for commercial application, the optimum electrode arrangement proved to be a bipolar configuration with horizontal plates. This gave a current efficiency of 86 pct with an energy requirement of 0.52 kwhr/lb lead. To determine the effect of impurity buildup in the bath, 1,200 lb of PbC12 prepared by ferric chloride leaching of galena concentrate was electrolyzed over a period of 2 months. Little deterioration of the metal quality occurred in that time; all of the lead produced had a purity equal to or better than corroding grade (>99.94 pct Pb).

Jan 1, 1976

By R. O. Dannenberg

The Bureau of Mines conducted laboratory investigations with the objective of developing an alternative process for recovering cobalt and copper from complex sulfide concentrates. Processes currently used depend largely upon precipitation techniques to remove impurities and recover cobalt from sulfate liquors prepared by oxidative pressure leaching of the sulfide concentrates. The Bureau conducted bench-scale research on a process for treating cobaltite concentrates, comprising (1) oxidative pressure leaching, (2) jarosite precipitation followed by H202 oxidation and pH control to remove iron and arsenic, (3) copper solvent extraction with a mixed hydroxyoxime-amine extractant, (4) copper electrowinning from recirculating acidic strip liquor, (5) selective cobalt extraction from copper solvent extraction raffinate with a phosphinic acid extractant, and (6) electrowinning of cobalt from a recirculating weak acid strip liquor. Overall cobalt and copper recoveries were 91.7 and 84.1 pct, respectively. Electrowon products assayed 99.8 pct Co and 99.89 pct Cu.

Jan 1, 1987

Dry weather since the third week in January has set back any prospects for an early increase in hydroelectric power in the Pacific Northwest, according to The Bonneville Power Administration. The 25% cutback made in July probably will not be restored in March or April. Noranda Aluminum, Inc., increased its price for 99.5% aluminum ingot from 66 cents to 70 cents per pound effective March 1, 1980. Revere Copper & Brass, Inc., also -increased its price for primary aluminum from 66.0 cents to 70.0 cents per pound effective February 1. Kaiser Aluminum & Chemical Corp. raised its international price for 99.5% primary aluminum from 72.6 cents to 82.6 cents per pound, c. i. f., effective February 26 on new orders and on shipments from March 15.

Jan 1, 1980

By J. N. Greaves

Investigations were conducted by the U.S. Bureau of Mines to develop flowsheets for the recovery of tungsten and gold from four Alaskan scheelite-bearing ores. Basic gravity concentration and cyanide leach tests were performed on all samples. About 46 pct of the tungsten and 30 pct of the gold from one sample were recovered in a gravity concentrate containing 24 pet W03 (tungstic oxide) and 119 troy ounces per short ton (tr oz/st) Au. Froth flotation of the gravity concentrate resulted in separate tungsten and gold products with grades of 38 pct W03 and 2,720 tr oz/st Au and recoveries of 60 and 97 pet, respectively. Additional gold was recovered from the gravity and flotation tailings by cyanidation. Overall recoveries of tungsten and gold from this sample were 28 and 94 pet, respeetively. A flowsheet with mill design parameters was developed that consisted of (1) free gold and scheelite recovery by gravity methods and froth flotation and (2) fme-grained gold recovery by cyanide leaching of reground gravity and flotation tailings, followed by a carbon-in-pulp (CIP) circuit. Data were developed from the Bond mill work index, gold and tungsten flotation, conventional and high-rate thickening, cyanide leaching, and CIP adsorption tests.

Jan 1, 1989

By J. C. Johnson

In situ stresses are important input data for the design of safe, stable stope layouts and extraction sequences. However, it is commonly assumed that normal and shear stress gradients in a stress field are negligible and, consequently, that stresses are uniform throughout the region of analysis. To evaluate these assumptions and to provide input data for an analysis of a shaft pillar mining plan, in situ stresses were measured at the Homestake Mine, Lead, SD, using overcoring on hollow inclusion cells and borehole deformation gauges. These measurements were used with conventional least squares, best fit data reduction schemes. The results showed that normal stresses within the shaft pillar were less than, but comparable to, those estimated from finite-element modeling. Shear stresses were an order of magnitude less than normal stresses and varied considerably from site to site. Possible causes of this variability include effects of scale, elastic moduli, anisotropy, and axial strain. Because of the variability, it is not possible to determine the magnitude of horizontal stress gradients.

Jan 1, 2010

By L. A. Neumeier

The Bureau of Mines investigated hot-rolling and forging characteristics of experimental ductile iron castings, both sand and permanent-mold, made with charges containing up to 70 pct foundry pig iron and 95 pct steelmaking pig iron. Between 1,550° and 1,950° F, most castings could be rolled to 90-pct reduction or forged to 70-pct reduction without serious cracking. Charge and composition have less bearing on workability than on subsequent properties. Permanent mold castings could be worked as readily as sand castings at 1,750° and 1,950° F. Plasticity improved with temperature. Small billets were also forged cold to 50-pct reduction without cracking. With equivalent nodularity, composition affects properties of wrought materials by altering matrix structure and strength. Properties vary with reduction and improve with increasing working temperature. Rolled material has high strength and anisotropy, and low ductility, particularly in the trans-verse direction. Annealing reduces strength and improves ductility, but anisotropy persists. At 70-pct reduction, impact resistance in the longitudinal direction is about twice that in the transverse. Annealing roughly doubles impact resistance. Deformation enhances damping capacity. The feasibility of die-forging and bar-rolling of ductile iron was evaluated in trial tests conducted under a Bureau contract. Although workability and ductility of ductile iron are inferior to those of steel, more advantage could be taken of ductile iron's plasticity to work rough shapes to final dimensions.

Jan 1, 1980

By O. H. Metzger

This is the first of two papers dealing with construction and use of aerial tramways in the metal-mining industry. It describes practices and equipment used in tramway construction and discusses the design of tramways. The second paper will describe the construction and operation of tramways and give operating costs. ACKNOWLEDGMENTS The author acknowledges the cooperation of a number of cable and tramway manufacturers Who supplied practical manufacturing data and other valuable information. Full credit for formulas used in the design of aerial tramways it given' to Edward B. Durham3/ and F. C. Carstarphen.4/

Jan 1, 1937

By D. S. Kingery

This study describes five fatal accidents so unusual in occurrence that the chain of circumstances bringing them about may never be duplicated. The intent of this publication is to illustrate that everyone working underground is subjected, at all times, to definite inherent mining hazards and that safety devices, though provided, often are ineffective or not used. It is hoped that a study of these fatal accidents in bituminous-coal mines will show workers and safety engineers that nothing can be taken for granted. Safety planning with continuous study can prevent these unusual accidents as well as the routine recurring types, which cause the majority of coal-mining injuries. The treacherous, fatalistic philosophy that "it can't happen to me" or that "when my time's up I'll get it regardless of what I do," still prevails among individuals and even safety engineers. The individual or safety man who believes in luck as applied to safety should not read any further, since this study was written for the sincere, safety-minded individual who accepts the prevention of all accidents as a challenge to his knowledge, initiative, persuasiveness, and salesmanship.

Jan 1, 1954

By Henry M. Harris, Hal J. Kelly

Electrical dewatering tests are described in which the laboratory cells were designed for continuous operation using an endless metal belt as the anode . The test slurries were dilute , containing from 2.5 to 14.4 percent solids (specific gravity of 1.02 to 1.10 ) that were all minus 8 microns in size . Recovery of the solids of low water content was the practical objective of the investigation . Process variables evaluated and reported are : The effect of feed rate , amount of electrolyte , samples from different sources , and the use of two cells in series . These variables are evaluated on the basis of yield of clay per kilowatt - hour , recovery , and the amount of solids in the deposited clay . Recovery , yield , and solid content of the belt anode product are interdependent , and changes that will improve one of these characteristics often are accomplished at the expense of the others . Tests in which recoveries range from 50 to 60 percent usually result in yields of 8 to 9 kilograms (kg ) of dry clay per kilowatt- hour (kwhr ) . Under these conditions , the solid content of the deposited clay approximates 50 percent . One test sample , composed of kaolinite , showed very high yield , 13 to 16 kg per kwhr ; high recovery , 53 to 58 percent ; and 52 to 54 percent solids in the cake .

Jan 1, 1964

By R. W. Dalzell

The performance characteristics, efficiency, and operating pressure of jute line-brattice systems were studied under varying underground conditions; various fabric grades and installation methods were used. The test results indicate that line-brattice system efficiency is dependent upon the method of ventilation the method of installation, porosity of fabric, and size of tight rib area.

Jan 1, 1966

By M. J. Reasor, M. DiMatteo, J. M. Antonini, K. Van Dyke, Z. Ye

"The inhalation of silica has been shown to produce a dramatic inflammatory and toxic response within the lungs of humans and laboratory animals. A variety of cellular and biochemical parameters are used to assess the silica-induced lung injury. The purpose of this paper is to introduce the use of luminok:Jependent chemiluminescence as a new method to study inflammation in both phagocytic cells and lung tissue recovered from silicaexposed animals. Chemiluminescence, or the emission of light, accompanies the release of reactive forms of oxygen when phagocytic cells are challenged. In this study, male Fischer 344 rats were intratracheally instilled with either silica (10 mg/100 g bw) or saline vehicle. One day after the instillations. a marked increase in the chemiluminescence was observed in the lung tissue and bronchoalveolar lavage cells recovered from the silica- treated animals when compared with the saline controls. The light reaction was markedly decreased by either superoxide dismutase or N-nitro-Larginine methyl ester hydrochloride. Superoxide dismutase is involved in the enzymatic breakdown of superoxide anion. while N-nitro-L-arginine methyl ester hydrocholoride, a nitric oxide synthase inhibitor, prevents the formation of nitric oxide. When superoxide anion and nitric oxide react. they form the highly oxidizing substance peroxynitrite. This study then implicates peroxynitrite as an agent that may be responsible for some of the oxidant lung injury that is associated with silica exposure. The use of luminol-dependent chemiluminescence may prove valuable as a method to measure the earliest events in the inflammatory process. and may be an adjunct in studying the mechanisms that produce inflammation. - Environ Health Perspect 102(Suppl 10):37-42 (1994) IntroductionResearch on inflammation has not produced a method that links the initial events of the process to the controlling events. Rather, a variety of parameters are measured that are the result of and not the basis of the inflammatory reaction. Parameters such as tissue weight, edema, blood flow, enzyme and protein release, or production of metabolites (prostaglandins, leukotrienes) have been used extensively. A method is needed that could be applied to cells of a particular type, groups of cells of different types, and even tissue, in an attempt to study the kinetics of the inflammation as well as being sensitive enough to monitor the early events of the process . Since inflammation is so complicated, the relationship between the control of the initial events and the oxidation process has never been explained nor studied in any derail."

Dec 1, 1995

By Phillip Allender, Wolf Karo, Knox Van Dyke, Lixin Wu, Ali Ardekani, Jorge Garcia, Jaime Gutierrez

"We report that two different micropolystyrene round beads linked to either luminol or lucigenin have been developed. The 1-µ.m-diameter beads arc useful reagents that allow one to perform chemiluminescent (light producing) phagoeytic reactions without opsonization. It is known that luminol reacts with peroxidases (e.g., myeloperoxidase) while lucigenin reacts mainly with superoxide anion. Luminol and lucigenin beads produce cellular chemiluminescence (CL) with neutrophils, macrophages, monocytes, and differentiated human promyelocytic leukemic cells (HL60). When myeloperoxidase (MPO) is present luminol beads evoke higher CL from neutrophils, but when little or no MPO is present, lucigenin beads produce higher amounts of light. Lucigenin beads appear to be active inside these cells where unbound lucigenin does not enter freely.INTRODUCTIONA variety of cells, e.g., neutrophils (Ns) and macrophages (Ms), can engulf foreign particles (1). This engulfing or phagocytic activity is used by the body to kill bacteria and to eliminate foreign particles such as respirable dusts, e.g., coal, silica, or cotton. The neutrophil engulfs or phagocytizes bacteria which are coated with plasma antibodies and/or complement proteins (Fig. 1). The coating or opsonization allows the neutrophil to recognize foreign substances. Usually the absence of opsonization prevents the cell's recognition of a foreign particle and the particle is not phagocytized. Macrophages, particularly the alveolar Oung) cells, do not require opsonization for phagocytosis. Ms should not be selective toward individual dusts because they serve a major role in eliminating a variety of these.Particle size can also be a factor. Usually a particle with a diameter of 0.5-5 µ.m is considered in the respirable range. Larger particles are trapped before they reach the alveoli Oung spaces where oxygen exchange with blood occurs), ·and smaller particles do not generally settle, and are not engulfed by macrophages (2). Tabato and Ikada (3) found that maximal phagocytosis of microspheres takes place when their diameter is in the range of 1.0 to 2.0 µ.m. In addition, they found that beads with hydrophobic surfaces were more readily phagocytized than hydrophilic surfaces."

Jan 1, 1990