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By John C. Machisak

INJURY EXPERIENCE AND EMPLOYMENT DATA on all stone quarries and associated plants in the United States are presented in this publication for the calendar year 1959. Such related operations as the manufacture of cement and lime and rock dressing are included. Data on clay and sand and gravel operations are not included and will be found in other Bureau publications on injuries and employment. The Bureau is authorized to make requests for such data and the information voluntarily submitted by the operators contributes to the promotion of safety in the quarrying industry. Every effort has been made to make this canvass as complete as possible. Data for production workers and office employees at the quarry site are included.

Jan 1, 1963

By S. Atallah

A survey was conducted relating to the current practices for the classification of hazardous locations in coal preparation plants. Several plants processing bituminous, anthracite and lignite coal in Pennsylvania, West Virginia, North Dakota, Colorado, Montana and Wyoming were visited. Coal preparation plant operations and designers as well as MESA inspectors were interviewed. The National Electrical Code was discussed with selected members of the NFPA committee and electrical equipment manufacturers. Data provided by MESA on fire and explosion accidents in coal preparation plants were examined. The requirements of the pertinent Federal Regulations, National Electrical Code, National Electrical Manufacturers Association and Underwriters' Laboratories were compared and evaluated. This report consists of two parts. Part I: "Analysis and Review" provides a summary of the findings. Part II: "Recommended Guidelines" consists of recommended uniform guidelines that may be used for interpreting the National Electrical Code as it applies to the classification of hazardous areas in coal preparation plants.

Jan 1, 1977

By Ann G. Kim

Studies on the initiation and propagation of mine fires have dealt almost exclusively with coal. It has been assumed that the self-heating potential of carbonaceous shales and coal wastes is relatively low. However, in abandoned coal mines and waste banks, initiation and propagation of fires may be strongly dependent on the self-heating tendency of these materials. The purpose of this study was to compare the self-heating probability of carbonaceous shales and coal wastes to that of coals. This study utilized a modified differential thermal analysis method, in which the combustion furnace temperature was the reference to which the sample temperature was compared. Based on the distribution of the maximum temperature differential and the sample heating rate, a self-heating probability value (SHPV) was calculated that corresponded to observed self-heating behavior. In this study, several of the carbonaceous shales and one coal waste had relatively high SHPV. The SHPV did not correspond directly to heating values or to differences in sulfur concentration.

Jan 1, 2010

By John C. Machisak

INJURY EXPERIENCE AND EMPLOYMENT DATA on all stone quarries and associated plants in the United States are presented in this publication for the calendar year 1959. Such related operations as the manufacture of cement and lime and rock dressing are included. Data on clay and sand and gravel operations are not included and will be found in other Bureau publications on injuries and employment. The Bureau is authorized to make requests for such data and the information voluntarily submitted by the operators contributes to the promotion of safety in the quarrying industry. Every effort has been made to make this canvass as complete as possible. Data for production workers and office employees at the quarry site are included.

Jan 1, 1963

By Thomas A. Phillips

An economic evaluation of the Bureau of Mines process for the separation of raw urban refuse into its metal, mineral, and energy components is presented. The process recovers ferrous metal, mixed nonferrous metals, aluminum, mixed-color glass cullet, and refuse-derived fuel products from raw refuse. Data for this evaluation were obtained from selected runs at the Bureau's pilot plant in Edmonston, Md. A cost estimate was prepared for a plant capable of processing 1,000 tons per day of raw urban refuse operating two shifts, 6 days per week. The fixed capital cost, based on second quarter 1976 equipment costs, is approximately $14.5 million excluding land and shipping containers. The estimated operating cost is approximately $8 per ton of refuse processed. This does not include credit for the products, transportation of the products, a tipping fee, or a dumping fee for wastes produced. No finance charges or taxes are included in the operating costs.

Jan 1, 1977

By M. M. Wong

Beryllium possesses attractive properties for use in the nuclear and space fields. Since fused-salt electrorefining can be employed to produce this metal in high-purity form from low-grade or scrap metals, the Bureau of Mines investigated electrorefining of beryllium in electrolytes composed of a LiC1-KC1 eutectic mixture plus varying amounts of BeC12. Results showed a 99- percent or better reduction of oxygen and magnesium and a substantial reduction of other minor metallic impurities. Extremely pure beryllium metal was produced. Operating variables, including BeCl2 concentration in the bath (3.5 to 16.5 mole-percent), temperature of operation (450° to 550° C.), and cathode current density (45 to 770 a,/sq, ft.), were studied; their effects on the deposition of metal, working condition of the bath, and purity of the refined metal are discussed. The safety precautions used in handling beryllium in the laboratory are also described.

Jan 1, 1962

By B. W. Madsen

To help maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines developed a mathematical model that describes acidic ferric sulfate leaching of copper from sulfide ores. The leaching model can aid in maximizing minerals and metals recovery from primary sources by giving operators and management a better understanding of the copper leaching process. This will aid in improving dump leaching operations. The model is based on a steady-state approximation of the continuity equation for diffusion of ferric ions in the rock pores and the intrinsic leaching kinetics of the various sulfide mineral particles. Ore characteristics included in the model were ore particle-size distribution, particle shape, grade, mineral content, mineral particle size, porosity, and tortuosity. The continuity equation was used with ferric ion concentration gradients and a fixed value for the diffusion coefficient. Except for effective diffusivity, each of these factors was either measured experimentally or estimated from theoretical considerations. The effective diffusivities were determined by fitting calculated leaching curves with experimental leaching data. Vertical variations in leach solution composition and temperature within a dump are not considered in this model. The model accurately predicted copper extractions for several large-scale tests during nearly 500 days of leaching.

Jan 1, 1981

By M. J. Ferrante

Laboratory-scale tests were undertaken to examine several electrolytes for possible use in separating nickel and cobalt from products being prepared at Nicaro, Cuba. The most extensive work was done with nickel sulfate-ammonium fluoride, ammonium fluoride, ammonium sulfate, and nickel sulfate-boric acid electrolytes. All four electrolytes exhibited some selectivity for dissolving nickel carbonate from Nicaro basic carbonate used for regeneration. The nickel sulfate-ammonium fluoride electrolyte exhibited less selectivity for dissolving nickel carbonate from Nicaro basic carbonate than it did from synthetic mixtures. Ammonium fluoride leaching experiments showed that a low concentration and high temperature gave a good nickel extraction with C. P. reagents; however, this was not confirmed in tests using Nicaro basic carbonate. Electrolytic tests employing ammonium fluoride leach liquors gave no further separation, since approximately 90 percent of the cobalt was deposited at the cathode with the nickel.

Jan 1, 1958

By William R. Barton

Sampling to determine development potential of beryllium deposits was conducted at 31 New England localities. A total of 54 additional areas where the geochemical environment appeared favorable were sampled to determine if economically interesting percentages of beryllia (BeO) might occur. Newry Hill-Plumbago Mountain, Maine, Iron Mountain, N.H., and Long Island, Maine, were investigated in some detail to determine the size and grade of deposits. The mineralized pegmatites at Newry Hill-Phunbago Mountain are extensive but very low grade; at Iron Mountain the ore bodies are very rich but of small volume; at Long Island beryl occurs with molybdenite, wolframite, and scheelite, but the tonnage of ore was not determined.

Jan 1, 1968

By Raja V. Rarnani, Robert L. Frantz

"The more than 75 research projects funded throughout the first 10 years of the Dust Center's operation have resulted in numerous cumulative findings fulfilling the goals of the Center. These project descriptions present the methodologies and project-to-project relationships leading to their various accomplishments and demonstrate the mesh between project objectives and Center goals.To develop equipment for collecting respirable dust samples.To develop experimental methods for particle-by-particle characterization of morphology, size, and chemistry.To develop experimental methods for overall respirable dust sample characterization of size distribution, chemistry, and crystallography.The project directly addresses the Center's goals to enhance the understanding of the scientific and engineering characteristics of fine and respirable mineral particles found in mining and milling atmospheres and to establish the relationship between natural and cultural factors (mine geology, mineralogy, mining and milling methods, equipment, and control measures) in the generation of fine particles. The project also aims to contribute to the development of control mechanisms for reducing ambient respirable dust concentrations and worker exposures.The work on this project is related to similar work on Coal Mine Dust Characterization (Project No. 2701/MN1) and Characterization of Dust Particles (Project No. 4203/PS3).Airborne dust sampling was performed at the following locations: 1) a sand and gravel quarry in Southern New Hampshire, 2) a welding facility, 3) a ceramic powder facility, 4) a metal powder facility, and 5) the air in Cambridge, Massachusetts. A portable sampling box incorporating two Sierra personal cascade impactors was designed and produced. At a 2-LPM flow rate, the effective cut-off diameters of the Sierra impactors were 10.0, 6.0, 3.5, 2.0, 0.9, and 0.5 mm, respectively, for each stage, and the air passed through a PVC filter after the last stage. In addition, the sampling box contained a total respirable dust filter. The substrates were weighed carefully before and after collection, and the weight increases were recorded. All films, foils, and filters were put in the balance chamber for more than 8 hours to stabilize the temperature and humidity before weighing. A Cash 21 microbalance (±0.001 mg) was used to weigh the Mylar films, SS films, and filters."

Jan 1, 1995

By J. L. Morning

During recent years, the Bureau of Mines has conducted an extensive investigation of the materials for making iron and steel. This work includes iron ore concentration, agglomeration, direct reduction of iron ores and concentrates, the production of pure manganese, chromium, and cobalt by electrolytic processes, the production of ferroalloys from low-grade domestic ores, and the development of special alloys to utilize these products. As a part of this general program, a Congressional appropriation allowed the con¬struction of an electric-furnace, semicommercial, ingot-producing plant at Shasta Dam near Redding, Calif. The primary objectives of the pilot plant were to determine the costs and operating problems involved in the production of steel and ferrous alloys in which sponge iron was used as melting stock, and to determine the physical properties of the materials produced. The pilot-plant equipment and the results of sponge iron-melting tests in the basic lined, electric arc furnace have been reported in previous publications.3/4/

Jan 1, 1953

By Oliver Bowles

ASBESTOS is a name applied to a group of naturally fibrous minerals. As indicated in a later section devoted to a detailed discussion of the early history of asbestos, the tern may be defined as a. fibrous form of serpentine or amphibole. It does not include fibrous forms of other minerals, such as wollastonite, nemalite (fibrous brucite), or the fibrous forms of calcite or gypsum. A material that has the characteristics of silk or cotton and at the same time will not burn is unique. Because it combines these qualities with other advantageous properties, asbestos has specialized uses for which no substitutes are yet available. Asbestos furnishes a major raw material for a great variety of essential products and their manufacture constitutes a vast industry. The United States leads all countries in the manufacture of asbestos products. The value of such commodities manufactured in 1952 exceeded $332 million. They are not only of vast importance to budding construction and industry but axe absolutely, essential to certain important fields of use, for example, steam packings and friction materials, such as brake-band linings on automobiles.

Jan 1, 1955

By R. N. Hambright

Gaseous and particulate exhaust emissions are characterized for a 1200 Bhp two-stroke cycle diesel, a 1000 Bhp four-stroke cycle pre-combustion chamber diesel, and a 900 Blip four-stroke cycle, direct injection diesel using steady-state modal testing and a versatile exhaust dilution-collection system. In addition, a 1.50 Bhp four-stroke cycle, pre-combustion chamber, turbocharged diesel was characterized for use in experimental water injection evaluations. Water injection downstream of the turbocharger compressor and upstream of the turbocharger exhaust turbine are evaluated for their particulate removal effectiveness on the small turbocharged diesel engine. The water droplets are inertially separated using cyclone separators designed for minimum pressure drop and outsize, lip to 50 percent of the total particulate mass generated was removed using a combination of both inlet and exhaust water injection techniques.

Jan 1, 1981

This manual is for use by mine operating personnel and vehicle manufacturers in the selection and proper use of automatic fire protection systems for underground metal and non-metal mining vehicles. Most of the currently available systems are manually operated, dry chemical fire suppression systems. When properly designed, installed, and maintained these systems have proven to be effective both in fire suppression and in withstanding the rugged mine environment. Portable fire extinguishers and manually actuated systems have provided adequate protection for most of the reported fire incidents. However, there have also been incidents where injuries and property losses would not have occurred if the vehicle had been protected with an automatic fire protection system. The need for reliable automatic systems exists when the operator is not present, especially when the vehicle engine is running without the operator in the cab; and also in cases where the operator leaves the vehicle to fight a small fire with a portable and is then forced to abandon the vehicle because the small fire becomes uncontrollable. In the later cases manual systems on the vehicle are never actuated. Although these incidents have been relatively few in number in the past, the increasing use of mobile diesel powered equipment and the related importance of personnel safety, high costs of the mining vehicles, and high cost of down time warrant consideration of automatic fire protection systems. The fire history data and the design concept discussed in this manual were developed under the Bureau of Mines Contract H0252038 which is part of the government's mining research safety program. The purpose of the contract was to develop a low cost, reliable, prototype automatic fire control system for underground vehicles. The industry needs were determined through an extensive mine visitation program, and the prototype system was demonstrated on a vehicle in an underground mine fire test. The system developed under this contract was specifically designed for a load-haul-dump. However, the design concept is applicable to the full general class of mobile underground mining equipment.

Jan 1, 2011

By T. O. Llewellyn

The Bureau of Mines conducted batch-?scale tests on a sample of parphyry copper mill tailings as part of a study to determine the feasibility of rutile recovery from this source. The tailings that were tested contained 0.75 percent titanium dioxide (Ti02), with about two-thirds of the Ti02 values occurring as rutile. Mineralogical studies indicated that about one-half of the Ti02 content could be considered recoverable. Beneficiation studies of the tailings showed that best flotation results were obtained when sulfides and carbonates were removed by bulk flotation prior to rutile flotation. Rutile flotation was most effective when a petroleum sulfonate collector was used in an acid circuit. From this basic method of flotation, two alternative procedures were developed. The first procedure was to size and grind the tailings to minus 200 mesh; deslime the total pulp; and then float the sulfides, carbonates, and rutile. The second procedure was the same, except that it did not include sizing and grinding. Flotation of the sized and ground tailings yielded rutile concentrates containing 43.1 percent Ti02 and 75.7 percent of the recoverable Ti02. Rutile concentrates floated from the tailings that were deslimed but not ground contained only 34.7 percent Ti02 and 69.4 percent of the recoverable Ti02.

Jan 1, 1980

By A. W. Fahrenwald

The art of flotation has developed rapidly. Numerous technical staffs and individual investigators have, by their combined efforts, developed practicable methods of concentrating ores which ten or even five years ago were considered complex and impossible of commercial treatment. Also the work of those who have been engaged in pure research on the fundamentals of flotation has helped greatly to expedite the general development of the process. However, in spite of the highly successful practical operation of the flotation process, results are obtained and things happen that we are unable to explain completely, although much is known about the theory of the process. The rapid stride in flotation concentration, it is noteworthy to point out, is due to the freer exchange of facts and data by the staffs of the larger mining companies and the patent controlling corporations, and by investigators in general. Generally speaking, one may visit any mining plant and by presentation of proper credentials, be shown all that is going on or that is being done.

Jan 1, 1925

By K. E. Tame

Pollution from radioactive nuclides, principally Ra226, in liquid waste from uranium mills can be minimized by reusing the waste solution within the mill. Such reuse of waste solution in the Vitro Chemical Co.-type process was investigated in the laboratory. Vitro employs an acid leaching process for dissolution of the uranium, countercurrent decantation for liquid-solid separation and washing, and amine solvent extraction for recovery of the uranium from solution. The simulated reuse of barren raffinate in the mill circuit was carried through two separate laboratory campaigns of 29 and 31 cycles. Conventional chloride stripping of the amine was employed in the first campaign, whereas nitrate stripping was used in the second campaign. Dissolution of uranium from the are in the acid leaching circuit averaged 96 percent. Washing efficiencies of 98 to 99 percent were attained by using 4 volume tons of combined raffinate and makeup water per ton of ore. Uranium recovery from the pregnant solution using a 5-percent solution of amine LA-1 in kerosine ranged from 99.3 to 99.9 percent.

Jan 1, 1962

By Michael J. Magyar

The Federal Bureau of Mines has developed a hydrametallurgical method to recover aluminum, aluminum oxide, and fluxing salts from aluminum salt slags. The slag is leached with water at room temperature to produce a saturated brine slurry. Screening of the slurry yields an aluminum-rich fraction that can be returned to the dross furnace. The remaining slurry is vacuum filtered, yielding a clear brine solution and an aluminum oxide filter cake. Evaporation of the clear filtrate produces a high-purity fluxing salt for reuse in the dross furnace. Over 80 pct of the metallic aluminum is recovered in the aluminum-rich oversize fraction, while essentially all the fluxing salts are recovered by evaporation. This report contains the final results of an investigation on a process research unit scale, an economic evaluation of the method, and recommendations to further improve the process.

Jan 1, 1979

By P. G. Pigott

This Bureau of Mines laboratory research demonstrated that building bricks meeting ASTM specification C62-66 for grades SW and MW of FBS-type bricks can be produced from waste copper mill tailings. Waste tailings from accumulations at Magna, Utah, Anaconda, Mont., and Hayden, Miami, and San Manuel, Ariz., were dry-pressed into bricks, and the products were tested in accordance with ASTM Designation C67-66 on sampling, and testing of brick. An evaluation derived from pilot-plant production of similar brick at the Coal Research Bureau of West Virginia University indicated the production cost to be about $34 per 1,000 bricks. Utilization of such mill tailings on a commercial scale would eliminate the need for digging new pits for brick raw material production, conserve natural resources, and simultaneously remove potential sources of air pollution.

Jan 1, 1971

By James Westfield

Drilling for roof bolting has created a new dust problem for the coal-mining industry. Drilling is inherently dusty, and control of dust produced by drilling vertical or nearly vertical holes is much more difficult than control of that produced by drilling flat or down holes.4/ Also, the dust produced by roof drilling differs in composition from that produced by drill-fur, or cutting the coal face because it contains a significantly greater amount of free silica and therefore presents a greater potential hazard of silicosis. Roof bolting has been practiced successfully in the mines of the St. Joseph Lead Co. in southeastern Missouri for over 20 years, but it was not until 1947 and 1948 that large-scale roof-bolting experiments were conducted in coal mines.5/ Although the need for dust control in conjunction with roof drilling was recognized from the beginning, the development and acceptance of roof bolting progressed so rapidly during 1949 and 1950 that solution of the dust problem lagged behind other engineering phases of the technique.

Jan 1, 1951