Search Documents

By E. G. Davis

The Bureau of Mines made laboratory-scale experiments to examine the technical possibilities of reclaiming manganese from slags produced by oxygen lancing of high-manganese pig iron. Ferromanganese was added to molten pig iron to yield a 4-to 5-percent manganese hot metal, which simulated a product obtainable from the blast furnace. This was injected with oxygen to reduce the metal to 1 percent or less manganese and form a slag containing about 40 percent manganese. The molten slag was water-quenched, treated with H2SO4) roasted at 660° C, and water-leached to give soluble manganese and iron sulfates. The sulfates were precipitated as hydroxides, converted to the oxide form, and smelted to produce a standard ferromanganese containing 74.6 percent Mn and 0.01 percent P. As an alternate method of manganese recovery, a manganese cell feed was prepared from the leach solutions and electrolytic manganese was produced. Direct smelting of the high-manganese slag resulted in 74.2 ferromanganese meeting ASTM specifications except for phosphorus content. The high phosphorus content of the metal and high slag-to-metal ratio obtained made this approach unattractive.

Jan 1, 1966

By Robert R. Perron

The U.S. Bureau of Mines is engaged in many diverse programs for improving mine safety. Of particular interest to the Bureau are new and improved means for minimizing the hazard of fire which can be initiated by prolonged low energy electrical faults on trolley line systems. When a high energy fault occurs on a trolley line, wherein the current exceeds the magnitude normally drawn by legitimate loads, such as locomotives, then the circuit breakers at close-by power rectifier sets trip. Tripping of the breakers not only protects the equipment at the rectifier sets, but also disconnects the energy source from the fault and thereby minimizes the fire risk. However, the fault current is frequently of a level substantially below that required to trip the overload breakers. When the fault is a substantial percentage of the set level of the breakers, the energy dissipated by the fault is frequently sufficient to clear the system by rapidly burning itself clear. Such a fault is often short-lived and does not present as serious a fire risk hazard as a prolonged, much lower energy fault, wherein the energy level is too low to clear the system. The breakdown of a trolley line insulator, in which there was a 20 or 30 ampere leak, would represent such a fault or illegitimate load and a substantial fire risk.

Jan 1, 1974

By Edward E. Johnson

The principal purpose of this study was the development of an engineering and economic model of a hypothetical large-scale open pit gold mining operation. The guiding concept in developing the model was the idea that, through study of a number of such models, it would be possible to evaluate a mineral property and to make reasonable estimates of the benefits to be derived from research in mining and metallurgy. The model by use of a computer is able to produce results easily and quickly when cost factors are varied. Cost factors may be varied as a result of assumptions of improved technology or of assumptions of assuming different approaches or methods to accomplish a particular segment of the mining or processing operation. The discounted cash flow rate of return was used to measure the effect of changes in costs or expected revenue. In this study, assumptions based on past processing practices were made in an effort to reduce costs of processing the ore These assumptions were: (1) Eliminating the low-grade cyanide circuit; (2) reducing the quantity of material to be processed by screening after crushing; and (3) using a combination of assumptions (1) and (2). All three assumptions resulted in reduced capital investment and operating cost that caused substantial increases in the rate of return.

Jan 1, 1968

By C. E. Julihn

In the fall of 1933 a new discovery of gold was made in the old Mojave mining district of California about 70 miles north of Los Angeles. It led to mining operations that have surpassed in their results all reasonable expectations and are of exceptional promise for the future. In less than 3 years, exploration has opened up a number of veins, from some of which a substantial amount of high-grade ore has been shipped, while a large tonnage of milling ore has been disclosed. Two mills, operating on ore averaging better than $12 a ton, will probably produce more than a million dollars worth of gold in 1936, and a considerable increase of their output in the following year is anticipated. While continuance of these operations for a number of years is already assured by ample reserves of ore, future discoveries of still other veins are reasonably possible, as occurrence of gold throughout the volcanic rocks of the district is widespread and the veins now being mined showed little to attract attention at the surface.

Jan 1, 1937

By N. S. Petersen

As part of the Demand Evaluation Program of the Bureau of Mines to determine future needs for minerals, a study was instituted to develop and describe a methodology for approaching the problem of substitution between mineral commodities and between mineral commodities and other materials. The report comprises three sections: A review of general factors relative to substitution, a case study of the effect of substitution on zinc die-casting markets in recent years, and a general methodology for reviewing materials substitution with specific emphasis derived from reviewing substitution in the domestic zinc die-casting markets.

Jan 1, 1971

By Lawrence G. Houk

Lithium is the lightest of all metals, but as it deteriorates rapidly in air it has no structural applications. Alloys of lithium that will float upon water can be made with other light metals, but these ultralight alloys are not useful in aircraft production or elsewhere at present. Alone or alloyed with alkaline earth meals, lithium acts as reining agent on molten metals, and as a minor constituent with other metals it imparts characteristic properties to the allay. Lithium compounds have somewhat wider application in commerce than either the metal or the alloys. They are used in the glass, ceramic, chemical, and air-conditioning industries and less extensively in the optical, pharmaceutical, electrical, and textile industries. The United States is the leading producer anti consumer of lithium ores and compounds and apparently has the largest known ore reserves. The value of lithium ores and primary chemical byproducts produced is relatively small, yet the lithium chemical industry yields products worth hundreds of thousands of dollars each year, owing partly to the high degree of purity demanded by the trade for most finished products and to the low combining weight of lithium. Fortunately, the low-grade ores can now be concentrated economically, and this fact, together with our extensive reserves, assures adequate supplies to meet any reasonable increase in demand. Lithium is listed as essential by both the American and British war agencies, and its military importance may be greatly enhanced.

Jan 1, 1942

By M. L. Skow

Large tonnages of the manganese ores found in Aroostook County, Maine, are refractory to conventional mineral-dressing techniques and to the common chemical- extraction procedures. The Maple Mountain-Hovey Mountain ores are typical of this type. Because the most promising method of recovering the manganese from these ores has been a chloridizing roast in which the ground ore is in contact with gaseous hydrogen chloride, preliminary batch tests were made with a fluidized bed. On the basis of these tests, it was concluded that fluidization, with careful control of operating conditions, could be employed for this cloridization and warrants further study. Selective volatilization of the iron at 600° C. was unsuccessful. An operating temperature of approximately 950° C. was necessary for a practicable rate of volatilization of manganese chloride. Hydrogen chloride contents of 10 to 100 percent of the fluidized gas gave essentially equivalent manganese recoveries with an 80- minute retention time, For shorter periods reaction was more complete with the higher hydrogen chloride concentrations. At the 80-minute retention period the lower hydrogen chloride concentrations volatilized somewhat less iron and also improved the physical operation of the process. Fluidization gave results superior to comparable tests on chloridization in a fixed bed.

Jan 1, 1956

By Albert E. Long

During the summer and fall of 1948 the Bureau of Mines, in cooperation with the U. S. Geological Survey, conducted 6xperiments in diamond core drilling in the Phosphoria formation in southeastern Idaho and southwestern Wyoming. Nearly all of the diamond core drilling in the Phosphoria formation has been done by mining companies interested in finding and developing phosphate-bearing beds amenable to stripping. The recovery of sludge; and enough core (usually 30 to 60 percent) to identify certain marker beds produced by current drilling practices meets both the primary requirement of mining companies in determining depth of overburden and their secondary need to determine the phosphate content of relatively thick minable units whose general composition and nature are already fairly well established.

Jan 1, 1949

By F. W. Wood

A program of research was conducted by the Bureau of Mines to investigate anomalies in electrical-discharge behavior during consumable-electrode arc melting of titanium and to study the effects of these irregularities on arc-furnace explosions. A major effort was devoted to an experimental survey of arc behavior and a qualitative definition of discharge phenomena.3/ An important conclusion was that the "glow" of industrial arc-melting terminology is not a glow discharge but a skittering arc in a displaced position. The conditions that permit displaced skittering were tentatively defined. The displaced skittering arcs tended to damage melting crucibles in two ways, and details of possible mechanisms leading to crucible rupture and explosive reactions have been proposed accordingly. However, no acceptable means of preventing crucible damage was discovered.

Jan 1, 1961

In 2007, a total of 4,639 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Stone mines comprised 31.2% of all mining operations. ? Mines producing the primary commodity of limestone (crushed and broken) comprised the largest number of operations (n=2,051; 44.2%). ? Stone mining operations were located in all states and territories except Delaware and North Dakota. ? Pennsylvania had the most stone mines (n=373; 8.0%), followed by Texas (n=352; 7.6%).

Aug 1, 2009

By David S. Yantek

A-weighted sound levels around vibrating screens in coal preparation plants often exceed 90 dB(A). The National Institute for Occupational Safety and Health (NIOSH) is actively developing noise controls to reduce noise generated by horizontal vibrating screens. A 121-microphone, 3.5-meter-diameter array was used to perform beamforming to determine locations of significant noise radiation on the screen. Below about 1 kHz, the screen body was found to be the most significant noise source. The beamforming contour maps showed several key locations on the sides of the screen and the feedbox are the most significant contributors. Operating deflection shape (ODS) analysis was used to examine the screen behavior under actual operating conditions. This information is helpful in determining how to modify the screen body to reduce the noise radiated by the screen below 1 kHz. The analysis showed modal vibration patterns on the sides and feed box were the main contributors to noise. The results show several areas on the screen sides and feedbox that can be modified to reduce noise.

Jan 1, 2009

By M. C. Malamphy

A general description of the activities and results of bauxite investi-gation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the sixteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project, except the deep holes drilled to test the geophysical anomalies. The locations of the latter holes show on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By W. A. Selvig

"The tests described in this paper were conducted under the sponsorship of Subcommittee VII on Pulverizing Characteristics of Coal, a subcommittee of Committee D-5 on Coal and Coke, American Society for Testing Materials, with a view to evaluating various laboratory procedures for testing grindability of coal in connection with commercial pulverization of coal for use as powdered fuel. The subcommittee, at a meeting in New York City on February 21, 1934, selected for test four methods that had been developed during the past few years for testing grindabilitay of coal and were being used by coal-testing laboratories in the United States and Canada. These methods are:Bureau of Mines method, Cross method, Fuel Research Laboratory method, and Hardgrove method. Subcommittee VII agreed that the grindability tests should be made on five coals selected to cover a wide range of hardness. The Pittsburgh Experiment Station, Bureau of Mines, was asked to direct the investigation and to prepare representative samples of the coals. Laboratories of the fol. lowing institutions and companies agreed to cooperate by making grindability tests: Babcock & Wilcox Co., Foster Wheeler Corporation, Fuel Engineering Co., of New York, Fuel Research Laboratory of the Canada Department of Mines, and Northwest Experiment Station of the Bureau of Mines.ACKNOWLEDGMENTSHelpful suggestions in planning the investigation were made by A. C. Fieldner, chairman, Committee D-5 on Coal and Coke, A.S.T.M., and chief engineer, Experiment Stations Division, U. S. Bureau of Mines, Washington, D. C., and E. B. Ricketts, research engineer, New York Edison Co., New. York City.The coal samples were supplied through the courtesy of floats, Wheeler Corporation, New York City; Philadelphia & Reading Coal & Iron Co., Pottsville, Pa.; Pittsburgh Coal Co., Pittsburgh, Pa.; and Pocahontas Fuel Co., Inc., New York City."

Feb 1, 1936

By James R. Boyle

The mining methods and practices used at the Young zinc mine, American Zinc Co. of Tennessee, have resulted in a low-cost, high-yield operation. Zinc ore (sphalerite) occurs in limestone-dolomite beds of the Kingsport Formation and is mined by modified room and pillar method. Utilizing trackless mining equipment which incorporates a high degree of flexibility, this operation has had a steady increase in productivity.

Jan 1, 1965

By Laurence G. Britton

Accurate flammability and ignitability data for chemicals form the cornerstone of procedures used to assess the hazards associated with commercial chemical production and use. Since 1967 the ASTM E27 Committee on the Hazard Potential of Chemicals has issued numerous, widely used consensus standards dealing with diverse testing and predictive procedures used to obtain relevant chemical hazard properties. The decision to issue a standard rests solely with the membership, which consists of representatives from industry, testing laboratories, consulting firms, government, academia, and instrument suppliers. Consequently, the procedures are automatically relevant, timely, and widely applicable. The purpose of this paper is to highlight some of the widely used standards, complemented with hypothetical but relevant examples describing the testing strategy, interpretation, and application of the results. A further goal of this paper is to encourage participation in the consensus standards development process. The paper is published in two parts. The first part (in the preceding issue of Process Safety Progress) dealt with the E27 standards pertaining to thermodynamics, thermal stability, and chemical compatibility. The second part, published here, focuses on the flammability, ignitability, and explosibility of fuel and air mixtures. © 2005 American Institute of Chemical Engineers Process Saf Prog 24: 12?28, 2005

Jan 1, 2005

By J. B. F. Champlin

The continuing development of the nuclear industry in the United States requires a program of waste disposal that insures against the release of large amounts of radioactivity to the environment. This paper describes research on one proposed means of disposal of this waste, that of injection into geologic formations at depth. Nuclear production plant wastes were simulated and injected into samples of sedimentary rock obtained from outcrops, quarries, and deep wells. Changes in the chemical and physical characteristics of the rocks caused by the interaction of ions and suspended particles in the waste solutions with the cementing material and claylike particles in the rock are discussed. Laboratory tests show that nuclear wastes can be injected into many natural porous, permeable geologic formations. Injectivity can be maintained over a longer period by monitoring the ionic balance and particle-size distribution of waste streams. The combination of permeability and porosity with low cation-retention capacity, as exhibited by most sandstones, would satisfy the engineering requirements for the subsurface disposal of nuclear waste. Shales and clays with their low permeability and high cation-retention capacity would make excellent confining formations. The amount of cation retained by sedimentary rocks increases with increasing valence or concentration of the cation or decreasing brine concentration. The use of rock cores as model reservoirs had proved successful in determining some of the parameters that need to be considered in full-scale field disposal of wastes.

Jan 1, 1967

By S. R. Rannels, D. E. Rannels

"I. IntroductionThe alveolar surface of the lung is covered by two populations of pneumocytes, type I and type II epithelium. The type I cell, which accounts for most of the alveolar surface area and provides a highly specialized barrier for gas exchange (Rannels et al., 1991), is poorly understood. Although approaches to type I cell purification have been discussed, they have not been applied widely because of the lack of phenotypic markers to monitor isolation procedures (Dobbs et al., 1988; Danto et al., 1992). In contrast, the type II cell has been studied extensively, largely because of the development of reliable procedures for its isolation and primary culture. Investigations based on the use of purified populations of cultured type II cells have provided convincing evidence to support a role for the pneumocytes both in the maintenance of normal lung function and in the response of the lung to injury (for review, see Rannels and Rannels, 1989).While type II cells can be isolated by a variety of approaches, the protocols used most commonly are modifications of the gradient method of Dobbs and Mason (1979) or of the panning method of Dobbs et al. (1986). Purification of the cells based on density gradient centrifugation is reliable and consistent, with yields of 30 to 40 X 106 type II cells per rat of 230 g body weight. Isolation procedures applied to a minimum of three to four rats provide the best results, as lower cell yields are common with the use of fewer animals. The protocol below is designed to obtain a maximal cell yield from the lungs of six rats.II. Materials and InstrumentationMaterialsCalbiochem: DNase I (Cat. No. 260912); Corning: culture flask, 75 cm2 #25115; Costar: culture plate, 24-well #3424; disposable serological pipette #4101; Elastin Products Inc: elastase #E-134; Falcon: cellulose nitrate membrane filter, 0.22 µm, #7105; conical tube, 50 ml, #2070; culture dish, 100 mm, #3003; culture plate, sixwell, #3046; Fisher: BaS04 , #B68-500; NaCl, #5271-3; NaHC03 , #5233-50; Fort Dodge Laboratories: pentobarbital, #1206-lE; Gibco: Dulbecco's minimal essential medium (DMEM), #430-1600EC; Hanks' balanced salt solution (HBSS), #310- 4185AG; Joklik's modified Eagle's medium (JMEM), #410-2300EC; HyClone Laboratories Inc: fetal calf serum (FCS ), # A-1115-L; I CN Biochemicals (Flow Labora tories): amphotericin B, #16-723-48; newborn calf serum (NCS), #29-121-54; try pan blue, # 19 5 5 32; Na/gene: Erlenmeyer flask, # 100-4116C; Pharmacia: Percoll, #17-0891-01; density marker beads, #17-0549-01; Sigma: gentam1cm sulfate, #G3632; penicillin/streptomycin, #P3539; trypsin inhibitor, #T9128; Tetko: HC- 160 nylon mesh, #3-160-53."

Dec 1, 1995

By T. J. Ballard

Chromite deposits in the vicinity of Louise, Troup County, Ga., were studied y the Bureau of Mines from September 1, 1942, to March, 15, 1943. They are about three-fourths of a mile southeast of Louise and 8 miles northeast of La Grange, Troup County, Ga. The existence of chromite deposits in that area has been known for more than 75 years, but no active prospecting was done until World War I. Prospecting continued intermittently' until 1928. The Bureau became interested in the deposits in connection with its strategic minerals investigations during World War II. The chromite in these deposits occurs as grains ranging from "pin-head" size to 3/8-inch and occasionally 1 inch. Some of the material is magnetic, indicating the presence of magnetite. Of the 300 samples taken during the course of the project, 266 were analyzed. Tables showing the analyses accompany this report.

Jan 1, 1948

By Diana K. Schimmelpfennig

Assessment of revegetation success on mined lands is a difficult, time consuming task and has been the subject of a number of controversies. Present regulations require that both plant cover and aboveground plant biomass be measured for use in making that assessment. Of these two variables, biomass is the most time consuming to measure and requires destructive sampling, a most undesirable requirement on fragile, recently revegetated areas. On the other hand, plant cover can be estimated using the point-frame method which is relatively nondestructive. In addition, vegetation can be sampled more uniformly with the point frame and in less time if species composition measures are to be made. A study was done to evaluate the predictability of aboveground biomass production on revegetated mined sites and adjacent native prairies using plant cover estimates made with the point frame method. The predictability of biomass production by cover estimates bears on the need for both measurements in assessing revegetation success. In general, a positive, statistically, significant correlation was demonstrated between plant cover (estimated by the point frame) and aboveground biomass (estimated by the harvest method) regardless of community type (mined or native), species composition, diversity or level of biomass production. However, the latter did have their effects on the relationship and must be accounted for in any predictive equations (that is to say, the predictive equations must be considered site-specific). Considering the relationship observed between the two parameters, cover estimation may be a sufficient indicator of revegetation success, especially where time and minimization of disturbance are critical.

Jan 1, 1982

By Nar S. Dalal, Xianglin Shi, Val Vallyathan

"INTRODOCTIONIn an earlier communication 1 from our laboratory it was reported that mechanical crushing of coal and quartz under normal air atmosphere generates of free radicals 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 Fubini 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 identified2 as being formed by the homolytic cleavage of the Si-0-Si bonds and the reactions of the Si• and SiO- radical with atmosphere. Fubini 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 Anca5 bad 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 radica1 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 radica1 measurements on a freshly made quartz dust. The dust's free radica1 content was measured using ESR spectroscopy while its cytotoxicity potential was estimated via hemolysis. Hemolysis was employed as the toxicity test because it is a widely used method for estimating the potential of a dust for disrupting the cell membrane. 8 The fibrotic potential was followed by measuring the dust-induced lipid peroxidation, using linoleic acid as a model lipid. As discussed below, the results obtained suggest new clues to the mechanism of the quartzrelated cytotoxicity and fibrogenicity. MATERIALS AND METHODSReagentsCrystalline quartz particles with a size range of 0.2-2.5 mm were obtained from the Generic Respirable Dust Technology Center, Pennsylvania State University, University Park, Pennsylvania. These particles were crushed in air to obtain quartz dust samples with particle sizes smaller than 20 microns. We chose to work with a dust with mixed particle sizes, rather than a specific range, as an effort to simulate the mining atmosphere. An agate mortar-pestle arrangement was used for the crushing and grinding because of the close similarity of the structure of agate to that of quartz. Diethylenetriaminepentaacetic acid (DETAPAC) were purchased from Sigma. All other chemica1s were purchased from Fisher or Aldrich.Hemolysls ExperimentsHemolytic activity of silica was measured, following an established procedure,9 as the amount of hemoglobin released from a 2 % suspension of sheep erythrocytes after incubation with 10 mg of silica dust for one hour at 37 °C. The hemoglobin release was estimated via the absorbance at 540 nm using a Gioford spectrophotometer. The procedure was calibrated by substituting the silica dust by a phosphate buffer solution as a negative control (background) and O.S % Triton-X-100 as a positive control (100% hemolysis). The percentage of hemolysis was calculated as follows:"

Jan 1, 1990