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By David A. Andrews

Coal occurs at many scattered localities in Arizona, California, Idaho, Nevada, and Oregon, but in most of the known occurrences thick coal beds are of small extent and the coal generally contains a high percentage of impurities. The coal beds occur at many different horizons in strata of Cretaceous and Tertiary age. Bituminous coal has been found in several areas, the most extensive of which is the Eden Ridge field of Oregon. Lignite also occurs in many places, but the only extensive deposit is in the Goose Creek field of Idaho, Nevada, and "Utah. The coal reserves of the region are largely of subbituminous rank; most of the subbituminous coal is in the Black Mesa field of northeastern Arizona and the Coos Bay field of Oregon. The Black Mesa field contains more than 80 percent of the coal reserves of all ranks but is remote from both transportation facilities and centers of consumption. Substantial reserves ill the Coos Bay field are favorably situated with respect to transportation and markets. ARIZONA Subbituminous coal occurs in the Black Mesa, Pinedale, and Gallup coal fields in Apache, Navajo, and Coconino Counties, Ariz. (fig. 1). Bituminous coal occurs in the Deer Creek field in Pinal and Graham Counties and in a small area in Apache County at the north-east corner of the State. All the coal beds are in strata of Cretaceous age. The coal in the Gallup field and at the northeast corner of the State lies in the Western edge of the San Juan structural basin. "Vest and south of this basin the coal-bearing strata have been removed by erosion except in high mesas.

Jan 1, 1947

By Ann G. Kim

The U.S. Bureau of Mines mine fIre diagnostic methodology to locate and monitor fIres in abandoned mines and waste banks is based on the controlled sampling of the mine atmosphere to determine changes in the concentration of hydrocarbons desorbed from heated coal. To provide background data for this methodology, a laboratory study was conducted in which samples of coal and coal waste were heated under controlled conditions. Gas samples from the combustion furnace were analyzed for standard gases CO2 and CO and for the C1 to Cs hydrocarbons. In all tests, the concentration of desorbed hydrocarbons increased during heating and decreased during cooling. A dimensionless hydrocarbon ratio, Rl, was developed as the signature for heated coal. For bituminous coals, the value of Rl increases during heating of coal samples and decreases during cooling of the same samples. Generally, Rl values of 100 or more indicate coal sample temperatures of at least 100° C. The emission of higher molecular weight hydrocarbons from anthracite samples was very low, resulting in relatively low Rl values at all temperatures. Data from fIeld projects confIrmed these results.

Jan 1, 1991

By L. C. IlsLey, M. W. Von Bernewitz

"Introduction.Several hundred thousand open lights are daily carried in coal mines of the United States, each lamp being a menace to life and property through fire or explosion. They have been responsible for many disasters in the past, and will be again. Flame safety lamps have been available for over a hundred years, but during the last ten years safe and practical electric lamps have been perfected. These have eliminated many of the flame safety lamps, and in a few mines have replaced open flame lamps. But there are still more than twice as many open lamps as electric lamps in our mines, and the open lamps should be discarded in favor of an approved type of electric lamp. There are several electric miners' lamps which have been approved by the Bureau of Mines for safety and efficiency, give good light, and are easily maintained and carried, some flame safety lamps will always be used, hut mostly for detecting gas; although they might be supplanted if some simple, reliable, and cheap gas detector were developed.Explosion Hazards from Open Lights.An open light and gas*** constitute a vicious hazard; while if there be coal dust present in the vicinity the consequences are multiplied many times. An open light and black blasting powder also constitute an explosion hazard, vividly attested by several serious disasters."

Jan 1, 1924

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Also included are tables that show the principal nonfuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of Volume I and in the State chapters of Volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1988

By G. L. Oldright, F. S. Wartman

"In the process of smelting copper ores and secondaries in the reverberatory furnace to produce a copper matte and a slag low enough in copper content to be discarded on the dump, it is essential to the best functioning of the process that most of the iron in the material charged into the furnace be at the end in the form of sulphide in the matte or ferrous oxide in the slag. Ferric oxide and magnetite present in the charged material should be reduced to ferrous sulphide or oxide. Ferric oxide offers no difficulty in reduction, at least to the magnetite stage, because it reacts very readily with sulphides at quite low temperatures. Magnetite is less reactive and consequently more resistant to slagging, so that the furnace man must take advantage of all factors favoring its reduction in order to prevent accumulations in the furnace.In order to determine these factors more definitely, the Bureau of Mines in cooperation with the Department of Metallurgy, University of Arizona, has undertaken at the Southwest Experiment Station an investigation of the effect of various factors upon the rate of reduction of magnetite by ferrous sulphide. A previous paper's reported the nature of the reactions taking place and the effect of various physical factors when only pure sulphide and oxide were present. Since in the actual smelting operation, many other substances are also present, it seemed desirable to make a study of the effect of their presence upon the rate of reduction of magnetite by ferrous sulphide. Such a study has been made; the work done and the results obtained are described herewith.As will be shown later, it has been found that of the substances usually present in the smelting charge, silica and magnesia accelerate, whereas lime, alumina, and cuprous sulphide hinder the reduction of magnetite by ferrous sulphide.No report of a previous laboratory investigation of this subject has been found. Almost all furnace operators have made at one time or another at least qualitative ccmparisons of the effect of various changes in operating oonditions upon the behavior of magnetite in the furnace, but the conclusions derived from the experiments have never been published."

Mar 1, 1931

By D. A. Hill

A survey of the literature on ELF and VLF atmospheric noise has been made. Most measurements have concentrated on the vertical electric field and the horizontal magnetic field rather than the vertical magnetic field which is of interest in transmission between horizontal loops. The limited vertical magnetic field data indicates that the vertical component is generally 10 to 20 dB below the horizontal component. Three laterally inhomogeneous earth models have been analyzed for conversion of horizontal to vertical magnetic field. The rough surface model examines surface effects, the inhomogeneous thin sheet model treats volume effects, and the buried cylinder model treats localized man-made effects. All three models predict the possibility of significant conversion from horizontal to vertical magnetic field. A thin sheet model has also been used to examine transmission from a buried magnetic dipole source. It is found that the predicted fields more nearly model the measured data than does the homogeneous half-space model.

Jan 1, 1982

By William R. Barton

COLUMBIUM (niobium) and tantalum are similar refractory metals with closely related properties and uses and close association in ore deposits. Until recently both metals, particularly columbium, were essentially laboratory curiosities. However, since the beginning of World War II, applied technology, under the impetus of national security requirements, has realized many chemical, electronic, nucleonic, and missile and rocketry applications, where high temperature or corrosive environments require the use of columbium or tantalum. At the same time, advances in these fields have resulted in intensive research on the geological distribution, resources, metallurgy, and properties of these two metals; their alloys and compounds; and the development of a full-fledged columbium-tantalum industry. The future appears to promise continued acceleration in such studies and ever-increasing demand for these elements. The raw material supplies of columbium are abundant, and the extractive metallurgy of columbium is well enough advanced to assure adequate supplies of the element at reasonable prices to meet any projected demands. Although the extractive metallurgy of tantalum is similarly well developed, raw material supplies are so limited that, lacking new ore discoveries, an increase in demand to five times the 1959 level would severely tax ore-production facilities. Approximately 120 tons of tantalum and about one-half as much columbium was produced in 1959. Additional quantities are consumed as compounds or additive alloys such as ferrocolumbium and ferrotantalum columbium (55).3

Jan 1, 1962

By Russell R. McLellan

As part of an effort to develop new or improved placer mining technology in the Tertiary gold-bearing channel gravel of northern California, the Bureau of Mines conducted investigations at the old Badger Hill placer mine in Nevada County, Calif., to collect data and information regarding drilling and sampling methods and deposit characteristics. Sampling studies involved the collection and processing of 400 tons of large-and small-volume samples from drill holes, underground workings, surface pits, and blasthole rounds. A total of 355 samples averaging 2,296 pounds per sample provided reasonably accurate data for analysis of the gold distribution. These studies indicated that the bulk of the gold is within 40 feet of bedrock in stacked, lenticular zones of cemented gravel that are largely confined to the relatively narrow, meandering course of the deepest portion of the bedrock channel. Drilling studies involved the testing of truck-mounted rotary, buckett and vibratory drills, none of which proved to be a completely versatile tool for sampling quickly and reliably both consolidated and unconsolidated gravel..

Jan 1, 1974

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 C. Özgen Karacan

Gob gas ventholes (GGV) are used to control methane inflows into a longwall operation by capturing it within the overlying fractured strata before it enters the work environment. Thus, it is important to understand the effects of various factors, such as drilling parameters, location of borehole, applied vacuum by exhausters and mining/panel parameters in order to be able to evaluate the performance of GGVs and to predict their effectiveness in controlling methane emissions. However, a practical model for this purpose currently does not exist. In this paper, we analyzed the total gas flow rates and methane percentages from 10 GGVs located on three adjacent panels operated in Pittsburgh coalbed in Southwestern Pennsylvania section of Northern Appalachian basin. The ventholes were drilled from different surface elevations and were located at varying distances from the start-up ends of the panels and from the tailgate entries. Exhauster pressures, casing diameters, location of longwall face and mining rates and production data were also recorded. These data were incorporated into a multilayer-perceptron (MLP) type artificial neural network (ANN) to model venthole production. The results showed that the two-hidden layer model predicted total production and the methane content of the GGVs with more than 90% accuracy. The ANN model was further used to conduct sensitivity analyses about the mean of the input variables to determine the effect of each input variable on the predicted production performance of GGVs.

Jan 1, 2009

By Melford H. Salsbury

The maximum net return from the sale of ores and concentrates of gold, silver, copper, lead, and zinc accrues to the producer when these mine products are marketed to the best advantage. Data are presented that the producer, especially the small mine operator, can use to survey available markets and make a preliminary estimate of the net return to be expected from an ore, on the basis of typical mill, smelter, and freight schedules. A review of the industry is presented by States in which recent production statistics are given, marketing facilities are discussed, and locations of principal mining districts, custom mills, and smelters are shown. Explanations of treatment processes, ore types, treatment charges, payments for metals, and deductions are given. Published rail and truck freight rates for mine products, based on marketing patterns developed over many years, are listed and explained.

Jan 1, 1964

By C. Hellar

A new dual-boom remotely controlled roof bolter was designed, fabricated, and then tested in an underground coal mine. Remote-control functions allowed complete bolting cycles to be performed on two booms with both operators located within protective cabs. Capabilities included 3-to 6-foot-long bolts in 5-to 8-foot seams, limited to bolts 20 inches shorter than seam height. Machine was in compliance with all regulations including dust collection, machine lighting, and permissibility.

Jan 1, 1979

Minerals are vital to any industrialized civilization. Annually, the United States uses more than 4 billion tons of new mineral materials, or about 40,000 pounds per person-about half being mineral fuels and the other half being metals and nonmetallics. Stable and economic domestic mining, mineral, metal, and mineral reclamation industries are essential to the economy. The value of United States energy and processed materials of mineral origin exceeds $200 billion annually. Although a number of minerals are imported, especially some designated as "strategic and critical," most U.S. mineral supplies are derived from the domestic mines and processing facilities that you will be seeing, reading about, and visiting as you use this visitor guide. We hope you enjoy your experiences. This pamphlet, a guide to mining and mineral operations that may be observed or visited and some other points of interest relating to minerals, is in-tended to aid tourists and students who are interested in mining. Some may wish to study our Nation's romantic past; others may plan to enter the minerals industry as a career; still others may have a primary interest in conservation practices. The pamphlet is also intended to aid State and local officials, Chambers of Commerce, and mining firms in answering some of the many questions of tourists and students.

Jan 1, 1977

By Robert I. Fujimoto

The work described was conducted to develop standards for the application of wire rope clips on wire rope. These standards include optimum number of clips and clip nut torques for wire rope sizes 1/4 through 2-1/4 inches, when used for forming an eye attachment in wire rope. Wire rope test specimens with clip attachments were load tested on tensile testing machines to determine an effective combination of clip nut torques and number of clips for each size of wire rope to develop efficiencies above 90 percent of the catalog ultimate rope strength.

Jan 1, 1973

By G. W. Marks, A. H. Roberson

"Previous investigation 4/ has demonstrated that some of the aliphatic amines are suitable absorbents for 302, This paper reports the results of physical studies of a number of such amines with the object of determining which is most favorable as an absorbent.Monoethanol amine, diethylene triamine, and triethylene tetramine appear to be the most promising of all the amines studied, and most of this report has been devoted to studies of the physical properties of their aqueous solutions, which contain varying amounts of SO2.PURITY OF MATERIALSAll of the amines used were of commercial grade, because the primary object of this research was the investigation of a proposed works process rather than the accumulation of scientific data.The aminoethyl derivitives of ethylene diamine, namely, diethylene triamine, triethylene tetramine, and tetraethylene pentamine, only recently have been produced commercially. The chemistry of aliphatic amines is complex, and these newer derivitives have not been investigated, completely. Chemically pure material is not on the market, and since definite physical standards have not been published, one could not be assured of a pure product even if the commercial material was refined.The compilation of physical constants for the pure amines would involve much time—consuming effort without materially enhancing the value of this paper, as this work was not devoted to the development of fundamental standards."

Oct 1, 1938

By Paul L. Campbell

Investigations by the Federal Bureau of Mines of methods of upgrading tar obtained by low-temperature carbonization of lignite showed that ß,ß?-oxydipropionitrile, ß,ß?-iminodipropionitrile, and ß,ß'-thiodipropionitrile were effective solvents for extracting aromatics (aromatic hydrocarbons plus polar compounds) from coal-tar neutral distillate fractions. Batch extraction showed that these solvents extracted approximately the same percentage of aromatics from various neutral oil fractions boiling between approximately 170° and 350° C. In continuous countercurrent extractions using oxydipropionitrile and iminodipropionitrile, approximately 30 to 35 vol.-pct, and 65 to 70 vol.-pct, of the aromatics in 170° to 350° C. neutral distillate oil were extracted at room temperature when solvent-to-oil ratios were 2:1 and 12:1, respectively. As the concentration of aromatics in the neutral distillate oil fraction decreased, the capacities and, to some extent, the selectivities of these solvents for the remaining aromatics decreased. Aromatics were isolated from the extracts and the solvents recovered by washing the extract fractions with a low-boiling paraffinic hydrocarbon such as heptane, using hydrocarbon-to-extract ratios of at least 2:1. The heptane wash removed most of the aromatics but only part of the polar compounds (compounds containing oxygen, sulfur, and nitrogen) from the extracts. The recovered oxydipropionitrile and iminodipropionitrile, containing polar compounds, were effective in extracting aromatics from neutral distillate oils. The contaminated solvents showed essentially the same capacities and selectivities as the pure solvents.

Jan 1, 1961

By L. M. Irwin

This Bureau of Mines investigation relates the physical properties of copper reverberatory furnace slags to changes in composition, The smelting of upper Michigan copper ore presents some problems that probably differ from those of other copper smelting areas. The study of these problems has, however, provided important data regarding slags in general and therefore will be of value to other operations as well. Conclusions reached from this study were: (1) Slag fluidity and refractive indices varied directly with the iron content and inversely with silica, lime, and alumina, and (2) there was no apparent correlation between slag fluidity and its copper content.

Jan 1, 1962

By Joseph A. Sutton

This study was undertaken by the Bureau of Mines to determine whether the sulfur-oxidizing bacterium Thiobacillus thiooxidans could use sulfur compounds to produce sulfuric acid in sufficient quantities to leach valuable metals from low-grade ores. The results of extended tests indicated that the bacterium is capable of extracting appreciable amounts of copper and cobalt from ore and mineral samples when sulfur is available in a state that can be readily assimilated by the organisms. Under the conditions of these tests, this organism was not able to assimilate and oxidize the sulfur as it occurred in the ores and minerals. Ores containing copper minerals in the silicate, carbonate, and oxide forms, in the presence of elemental sulfur, were more susceptible to bacterial action than ores containing copper minerals in the sulfide form. Thiobacillus thiooxidans remained active on elemental sulfur in the presence of some of the ores which were tested, but could not tolerate others. Therefore, strains of the bacterium were progressively adjusted to increasing concentrations (0.5 to 10 grams) of the individual ores until they could remain active on 10-gram portions of all ores being tested.

Jan 1, 1961

By Raymond W. Hiteshue

Experiments were conducted al temperatures of 480° to 800° C. and hydrogen pressure of 6,000 p.s.i.g. to determine the effect of coal residence time on the conversion of a high-volatile bituminous C coal to liquid and gaseous products when using a semicontinuous apparatus designed fur rapid heating and cooling of reactants. The objective of the studies at high temperatures was to determine if appreciable quantities of coal could be converted to gaseous hydrocarbons and low-boiling liquid hydrocarbons. Experiments at lower temperatures were designed to indicate shifts in product distribution with respect to temperature and to learn more about the general mechanism of the reaction when using close control of coal residence time. One percent molybdenum, based on m.a.f. (moisture-and ash-free) coal, was used throughout this investigation. At 800° C., 6,000 p.s.i.g., and "zero" residence time) the yield of gaseous hydrocarbons was about 38 percent and the yield of oil about 4.5 percent, based on m.a.f. coal. With IS minutes residence time, under the same conditions, the yield of gaseous hydrocarbons was approximately 80 percent with no increase in yield of oil. Apparently at 800° C., and hydrogen pressure of 6,000 p.s.i.g. coal was rapidly carbonized to char with expulsion of volatiles. Char was then slowly hydrogenated to gaseous hydrocarbons without production of oil.

Jan 1, 1962

By D. D. Hamilton

The ISMS program provided for the development and demonstration of equipment modifications in both conventional and continuous coal mining systems. This report describes activities during the demonstration of the continuous equipment and includes machine performance, results of data gathering, system evaluation, and recommendations for implementing improvements.

Jan 1, 1976