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By Robert F. Pettit

This paper on methods and costs of mining and milling iron ore at the Iron Mountain mine of Ozark Ore Co., St, Francois County, Mo., is one of a series of Bureau of Mines reports on methods, practices, and costs of mining and milling throughout the United States. The Iron Mountain operation is notable for its successful transition from open-pit to underground mining, for use underground of large earth-moving equipment, and for development of a multilevel room-and-pillar mining method. Milling methods also have undergone transitions - from hand sorting and log washing in the early days to gravity concentration. Milling ultimately may include flotation to recover additional iron from products now discarded as tailing,

Jan 1, 1957

By P. D. Kovscek

The performance of a novel prototype kerf-cutting impact mining machine was evaluated under a cooperative agreement between the U.S. Bureau of Mines and RAMEX Systems, Bellevue, WA, while operating under conditions typical of normal tunnel entry development. Selected operating parameters were monitored concurrently to determine baseline operating conditions and to study relationships between operating parameters. Using the data obtained, the specific energy requirements of the impact mining machine were calculated and compared to specific energy requirements of tunnel boring machines cutting in rock having similar hardness. Tests results indicate that the kerf-cutting impact mining machine can provide a mechanical means for mining very hard rock that cannot be effectively mined using commercially available mechanical excavators.

Jan 1, 2010

By K. K. Kelley

Thermodynamics data for silicates have applications in the fields of extractive metallurgy, ceramics, and geochemistry. To facilitate these applications, up-to-date tables of heats and free energies of formation are needed. It is the purpose of this report to supply such tables for anhydrous silicates. During the last 15 years the heats of formation of a substantial number of anhydrous silicates have been reliably determined at or near room temperature. This resulted from the development (first by the Bureau of Mines and later by the Geophysical Laboratory of the Carnegie Institution of Washington, by the Institute of Geology of the University of Helsinki, Finland, and by the Department of Geology of the University of Chicago) of accurate solution calorimeters, employing hydrofluoric acid as the reaction medium. Specific references to work of these laboratories will be made in the next section of this report. Also, entropy data at 298.150 K. and high-temperature heat-content values are available for many of these silicates, mainly owing to work of the Bureau of Mines. Most of these entropy and heat-content data have been compiled in Bureau of Mines Bulletins (13, 15).3

Jan 1, 1962

By J. B. Zink

The Bureau of Mines developed a spectrochemical method to determine six constituents in coal ash in the following concentration ranges: silica 9 to 63 percent, alumina 7.5 to 35 percent, ferric oxide 2 to 30 percent, calcium oxide 1 to 29 percent, magnesium oxide 0.5 to 6 percent, and titanium oxide 0.5 to 4 percent. Samples of coal ash are fused with a mixture of lithium tetraborate and vanadium pentoxide. The resulting beads are crushed, mixed with powdered graphite, and briquetted. The pellets are analyzed spectrographically, using controlled high-voltage spark excitation. Vanadium serves as the internal standard. Effects due to matrix variations are minimized by fusion with lithium tetraborate. Intensity ratios of selected analytical lines are determined photometrically, Concentrations are read from analytical curves, prepared from synthetic standards, relating log intensity ratios to log concentration. A combustion procedure is used to determine sulfur tri-oxide. The method is most useful when large numbers of coal ashes must be analyzed but a high degree of accuracy is not essential.

Jan 1, 1967

By A. Oyler

The U.S. Bureau of Mines has compiled data on the major causes of fatal and nonfatal electrical accidents related to mining, and their associated costs, for the 1980-85 period. Specific electrical problem areas were identified, allowing future research to be focused on reducing the frequency of these occurrences. Recommendations for reducing the number of electrical accidents and injuries are provided. The four mining sectors for which data were gathered and compiled are (1) underground coal mines, (2) surface at underground coal mines, (3) underground metal-nonmetal mines, and (4) surface at underground metal-nonmetal mines. Nine categories of information pertaining to specific aspects of the accident are used in this report: activity engaged in when the accident occurred, source of injury, job title, mining method, location, machine, nature of injury, accident type, and part of body affected. The number of years of experience at the specific job the employee was performing when the accident occurred, time of accident, and in the case of nonfatal accidents, the total days lost per year, are also summarized.

Jan 1, 1990

By K. D. Plants, J. H. Holden, L. F. Willmott

Pulverized high- volatile A bituminous coal was gasified with oxygen and superheated steam in a pressure - gasification pilot plant equipped for steampickup feeding . The pilot plant operated satisfactorily at relatively high steam- to - coal ratios , but steam- to - coal ratios could not be reduced much below 0.5 lb / lb without condensation of steam or softening of the coal . Carbon gasified , gas composition , and coal and oxygen requirements were essentially the same as for a pilot plant equipped with a fluidized coal feeder . Average results from the pilot plant equipped for steam- pickup feeding were coal requirement , 37.3 lb/M ( 1,000 ) scf of CO + H₂ produced ; oxygen requirement , 358 scf /M scf CO + H₂ produced ; and carbon gasified , 87.7 percent .

Jan 1, 1964

By P. L. Weston

The Bureau of Mines used high-temperature reduction roasting, magnetic separation, acid-leaching, and autoclave precipitation processes to recover iron and manganese from brown Cuyana range ores of Minnesota. Wet magnetic separation concentrated over 90 percent of the iron in 3 of 4 ores as high grade products analyzing 74 to 85 percent iron, 2.5 to 6 percent manganese, and 3 to 10 percent SiO2. The nonmagnetic fractions were leached with dilute sulfuric acid extracting 83 to 93 percent of the contained manganese and small amounts of iron. The leach solutions contained Mn-to-Fe and Mn-to-SiO2 ratios favorable enough for possible consumption in metallurgical mane operations. Exceptionally pure Mn solutions were achieved by pressure precipitation of the remaining iron in an autoclave followed by lime precipitation of silica and alumina.

Jan 1, 1966

By J. H. Wiggins

The evaporation of crude oil without doubt causes one of the largest single losses to which the oil is subjected after it is taken from the ground. The few days during which crude oil is stored on the lease before being taken by the pipe line, causes an aggregate loss per year from evaporation estimated at 122,100,000 gallons of gasoline in the Mid-Continent field alone. This has a value, at 22 cents per gallon, of $26,880,000 and represents about 3 per cent of the total gasoline produced in the United States from all fields and all sources. The following table shows this in more detail:

May 1, 1920

By L. R. Burdick, J. F. Barkley

"The agglomerating index of coal is an index based upon the nature of the coke residue left when the standard volatile-matter determination of the well-known proximate analysis is made. In this determination a small amount of coal is heated in a container to about 950° C. (1,742° F.), at which temperature the volatile matter is driven off, leaving a coke formation. The coke residues for various coals are quite different in physical structure: and, for some time past, work has been done on studies of the nature of these residues in connection with the coking of coal. In 1934 Gilmore, Connell, and Nicolls proposed use of the agglomerating index for indicating the dividing line between noncaking coals and those having weakly caking properties. 4/ Its use was adopted in the standard classification of coals by rank as a requisite physical property index to differentiate semianthracite from low-volatile bituminous coal and also high-volatile ""C"" bituminous from subbituminous ""A"" coal, as shown in table 1, the standard coal classification adopted by the American Society for Testing Materials and the American Standards Association. 5./In studying the agglomerating properties of coals based on the coke residue the Bureau of Mines has adopted the notation given in table 2. Coals that in the volatile-matter determination give a coke residue either in the form of an agglomerate button that will support a 500-gram weight without pulverizing or a button that shows swelling or cell structure are considered to be agglomerating."

Nov 1, 1938

By R. L. Grant

The principal official test performed by the Bureau of Mines to determine the permissibility of coal-mine explosives, commonly referred to as the gallery test, has been in use at the Bruceton station for many years (2, 16).4/ In this test the explosive under study is loaded into the borehole of a steel cannon and fired into a flammable mixture of natural gas and air or natural gas, air, and coal dust. To meet the requirements for permissibility, the explosive must not ignite the gas mixture under the conditions of the test. There is little doubt that these tests have succeeded in the main objective, namely, to screen the relatively safe from the relatively hazardous explosives. It has been generally conceded that adoption of permissible explosives by the coal-mining industry in the United States has substantially reduced the frequency of disastrous underground explosions caused by blasting. In recent years, however, research workers planning programs for improving the safety of coal-mine explosives have felt the growing need of a more quantitative method for measuring the incendivity of explosives based on a better understanding of the role of the important variables in the gallery tests, Accordingly, it was decided to apply certain statistical methods and techniques to the gallery test to develop it into a more precise tool for evaluating permissible explosives. One of the first and more important methods applied for this purpose was the up-and-down technique (6,7,17), It was demonstrated (14,15) that the weight of the explosive charge directly affects the ignition probability of the natural gas-air atmosphere and that the curve of ignition probability versus charge weight is a cumulative normal curve. Following these experiments, a program, still in progress, was set up to study how the addition of sodium chloride to various permissible-type ex-plosives affects their incendivity. This program resulted in 3,294 shots,

Jan 1, 1961

By D. L. Soreck

The hazards to the public posed by abandoned mine shafts are well documented. As private development encroaches on previously mined areas, the potential for fatalities and serious injuries from abandoned mine shafts increases. The U.S. Bureau of Mines has conducted research into cellular concrete as a material for sealing these openings. The current work involves testing the characteristics of cellular concrete before and after it had been pumped or dropped from different heights into a simulated mine shaft. Cellular concrete was pumped vertically up to and subsequently dropped from heights of 18 and 37 m into concrete forms. Wet density measurements were made at multiple sampling points in the test circuit. Air content determinations and uniaxial compressive strength testing were conducted. Research results showed significant loss in air content and changes in the characteristics of cellular concrete during pumping or dropping from various heights. Recommendations on effective use of cellular concrete for sealing abandoned mine shafts are made.

Jan 1, 2010

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 R. R. Brown

The solubility and the activity of aluminum chloride hexahydrate, A1C13?6H2O, in aqueous solutions were determined as a part of the Bureau of Mines, U.S. Department of the Interior, research to improve mineral processing technology for recovering alumina from low-grade domestic resources. The solubility of A1C13 in pure water was found to be 31.09 and 31.77 wt-pct at 25° and 85° C, respectively, and decreased drastically to 10 and 0.1 wt-pct when the respective amounts of 20.3 and 37 wt-pct hydrochloric acid (HCI) were added in solution. The equilibrium constant for the solubility of hexahydrate, activities, and activity coefficients of A1C13 and H2O were calculated and compared with the results from the available methods of estimation. The results were shown to be useful in leaching nonbauxitic ores for extraction of alumina by changing the solubilities of component salts upon addition of HC1. Simultaneous solubilities of A1C13, FeC13, KC1, and NaC1 in solutions of HC1-H2O were also determined and their effects on the purity of A1C13?6H20 crystallized from mixed salt solutions are briefly discussed.

Jan 1, 1979

By W. W. Adams

The United States Bureau of Mines, in cooperation with the National Send and Gravel Association conducted a safety contest in 1929 Among producers of sand and gravel. Only 26 plants were enrolled, as the contest was late getting under way. It is hoped that a ranch larger number of plants will be represented in the safety competition of 1930. Two trophies, both of which were provided by Rock Products magazine, were awarded at the end of the contest; one trophy was given for the best safety record among plants working 100,000 or mare man-hours during the year and the other for the beat record among plants working less than 100,000 man-hours. The trophies were presented to representatives of the winning, companies on January 29, 1930, at the annual convention of the National Sand and Gravel Association at Memphis, Tenn.

Jan 1, 1930

By P. Comba

The U.S. Bureau of Mines investigated a hydrochloric (HC1)-calcium fluoride (CaF2) leaching procedure to treat domestic manganese (Mn)-bearing silicate resources. The proposed process is an alternative to high-temperature and energy-intensive extractive techniques. Single-stage leaching with a stoichiometric amount of HCl and a F-Mn mole ratio of 0.2 extracted 96 pct of the Mn when the leach conditions were 50° C, 3 h, and 35 pct solids. Ninety-eight percent of the Mn was extracted during countercurrent leaching at similar conditions. A process flowsheet was developed that incorporated HC1-Cab leaching, excess leach acid utilization, fluoride (F) recycle, and Mn recovery. When the domestic manganese silicate ore was processed, 98 pct of the Mn was extracted, 99 pct of the Cab was reclaimed, and a leach residue was produced that passed the Environmental Protection Agency (EPA) Extraction Procedure (EP) Test for nonhazardous waste.

Jan 1, 2010

By Stephen A. Swan

Certain types of mobile surface mining equipment are required to be equipped with rollover protective structures (ROPS) capable of protecting the operator in case of a rollover accident. The Bureau of Mines has developed ROPS performance criteria for wheeled front-end loaders. This report reviews the development of rollover test procedures and subsequent testing of ROPS for 52,000-, 286,000-, and 390,000-lb gross vehicle weight (GVW) loaders. The program consisted of both dynamic (roll) and static tests to assist in the development of the ROPS performance criteria. Each test included extensive instrumentation and photographic documentation to fully evaluate the performance of the ROPS. Data summarizing side, longitudinal, and vertical force and deflections are included. The data indicate that for loaders in excess of 240,000 lb, GVW, a side force-to-mass ratio of 1.0 and an energy-to-mass ratio of 6.0 appear to be adequate criteria to protect an operator in the event of a 5400 rollover. For smaller machines, Society of Automotive Engineers (SAE) 11040 performance criteria provide adequate protection. Longitudinal loading, though not ad-dressed in previous ROPS performance criteria, was shown to be a potentially significant factor in ROPS failure. Longitudinal loading and energy criteria equal to 80 pct of side loading criteria are recommended.

Jan 1, 1988

By W. L. Crentz

Knott County is one of the smaller coal-producing areas in the Eastern Kentucky coal field. It contains numerous coal beds, many too thin to support mining over a wide area, Coal produced in the county is from a few rail-shipping operations and many small truck mines. Many smaller mines are working beds whose exact location in the coal-bearing strata is uncertain. Samples were collected from 11 different coal beds, of which the Fire Clay, Hindman, Upper Elkhorn No. 3, and Flag are the most import ant from a product ion standpoint. Known reserves in the Hindman bed. are very limited, and almost the entire production from this bed is gathered from two comparatively, large rail-shipping mines in addition to the four principal beds, samples were taken in the Francis, Haddix, Fire Clay Rider, Whitesburg, Amburgy, Upper horn No. 2, and Upper Elkhorn No. I .beds. Figure 1 is a typical section of the strata, showing the more important coal beds and. readily identifying their location with respect to each other. The bed names as shown are particularly important because of the local tendency to assign several names to the same bed. To avoid confusion, the names by which each coal bed is known also are given in the following listing. The coal. beds., in descending order, follow: [ ]

Jan 1, 1953

By A. O. Ipsen

As part of the Bureau's intensive investigation of domestic manganese deposits, lots of ore for testing were collected by Bureau engineers during examinations of several properties in Juab County, Utah. One low-grade and two intermediate-grade samples (13.5, 25.3 and 27.5 percent manganese) were procured by engineers of the Bureau of Mines from the 900--and 1,100-foot levels of' the Tintic Standard mine, situated 2 miles southeast of Eureka, Utah. The ore bodies were described as blocks of ore approximately 60 feet long, 40 feet wide, and 20 to 100 feet deep. The manganese-iron association in the Tintic Standard ores was intimate, and no significant concentration of the low-grade sample was made by ore dressing, However, both of' the higher-grade samples were readily beneficiated to marketable manganese products. Ore from the Oxen No. 5974 claim, 2 miles northeast of Eureka, Utah was low in grade (19.4 percent manganese) and was not amenable to the production of high-grade concentrates owing to the intimacy of association of the manganese minerals with silica. However, a fair manganese recovery was obtained in a product that, when sintered, assayed plus 40 percent manganese. The ore body is reported to be a replacement in limestone and is composed of manganese oxides intermixed with silica, decomposed rhyolite, and limestone. The Fields property consists of five mineral claims situated 3 miles north of Eureka, Utah. The deposit is a replacement in a contact between limestone and a quartz dike. Tests were made on representative samples of a 50-ton lot stored on the property. Although the mineral association in the ore (22.2 percent manganese) is not particularly complex, the physical properties of the manganese minerals render the ore refractory to ore-dressing beneficiation. As the ores varied widely in physical and chemical characteristics, samples from each property were considered as separate ore-dressing problems.

Jan 1, 1949

By Manuel Gomez

A lignite from Milam County, Tex., has been oxidized by air at temperatures from about 27° to 300° C. for varying lengths of time. The oxidized coal was carbonized at 500° C. in a laboratory assay unit, and the products of carbonization were measured and analyzed. The data presented suggest that, as lignite is progressively oxidized, tar yields are decreased and gas yields are increased in a ratio approximating 1:1. It is surmised that tar-yielding structures in the nonoxidized coal produce gas, principally, when the coal is oxidized. Char-yielding structures of the nonoxidized coal give rise to additional water of decomposition after oxidation and pyrolysis. As lignite is subjected to greater oxidation, the gaseous product evolved on pyrolysis becomes almost entirely carbon dioxide. Tar yields decrease with an increased degree of oxidation, so that the reduction in tar yield may be used as a qualitative measure of oxidation. Pilot-plant drying and carbonization, where air is used as the transport gas and where some air is included in the drying and carbonizing gases, induces some oxidation of the coal particle. The short residence time in a fluidized system with reference to the oxidation environment limits the oxidation.

Jan 1, 1956

By G. E. McElroy

[The purpose of this paper is to present type: of charts adapted to aid in the graphic solution of fan-performance problems of selection and operation, and to urge the adoption of similar charts by the National Association of Fan Manufactures as standard forms for presenting fan-performance data. As matters now stand, it is difficult for the average engineer to solve such problems because a large number of variables are involved, and performance data are not presented in a manner that permits their direct application to many problems encountered in practice. The performance of any centrifugal machine is determined not only by the machine itself but also by the fluid-flow system on which it operates. Actual performance of centrifugal fans is therefore a matter of the type, size, and speed of fan, on the one hand, anti of the relation of pressure to quantity of flow, as determined by the physical condition of the airway s: stem, on the other.]

Jan 1, 1936