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By Oliver Bowles

"General.The term mica is probably derived from the Latin ""micare"", meaning to shine or glitter, for the brilliant reflection from mica flakes in rocks has directed more than ordinary attention to this group of minerals. Mica includes a group of several minerals all characterized by a perfect basal cleavage, by virtue of which they may be split into exceedingly thin plates. The minerals are of very common occurrence in all countries, constituting about 4 per cent of the igneous rocks of the world The term ""isinglass"" is sometimes applied to glazing mica, but this is incorrect, for true isinglass is a soluble combustible material made from the air bladders of certain fish. As a constituent of granites and schists, mica is present as flakes too small for commercial use. Mica occurs also as small scales in many sandstones. When granites decompose, the quartz and the white mica are the most resistant to weathering, and so remain when the other constituents have been decomposed and carried away. A secondary white mica known as sericite is formed by the metamorphosis of clay-bearing rocks, and thus, in extremely fine-grained form it constitutes an important constituent of slates and related rocks. Some schists contain a high percentage of mica, but the presence of large amounts of quartz and other minerals has up to the present time rendered them useless as commercial sources of mica for grinding. It is possible, however, that certain mica or seri-cite schists which are composed almost wholly of mica with very little quartz may be utilized for ground mica if found in large enough entity. Considerable micais sometimes found mixed with the residual kaolin that results from decomposition of pegmatites, and in one locality at least it has been recovered as a by-product in a clay purification plant."

May 1, 1922

By Lulie H. Crump

U.S. supply and demand data for dry natural gas by source, form, and major consuming sectors--within and between States and defined regions--were tabulated for the years 1960 and 1965. State-by-State quantitative data are provided for the natural gas industry that can be arranged into regional groupings and used to determine regional flow patterns. The tables show the derivation of the total supply of gas available for consumption from total marketed production. The tables also report the distribution of the supply among the major consuming sectors (household and commercial, industrial, transportation, and electricity generation, utilities). The summarized data show an increase in the absolute demand for natural gas in all regions for the period 1960-65, although the relative posit ions of the various subregions, with respect to national consumption, remained about the same. To enable comparison of data on dry natural gas with data on other energy sources, quantities in terms of million cubic feet were converted to British thermal unit (Btu) equivalents.

Jan 1, 1969

By E. C. Lane

This paper is the first putt of a report giving the results of the Bureau of Mines' twenty-third semiannual survey of motor gasoline marketed in the United States. A companion report, Part II, is in preparation and will give a more detailed discussion of the whole survey. Results of the determination of copper-strip corrosion, color, sulphur content, copper-dish evaporation residue, and gum content as given by the Bureau of Mines steam-oven method will be presented in the second paper, which will also include the prevailing retail price and the tax at the time the sample was taken. This paper deals specifically with data relative to gravity, Reid vapor pressure,' and distillation (method 100.13).6 The samples tested were divided into "competitive-price gasolines" and "premium-price motor fuels," a method of presentation that was begun with the twenty-second semiannual survey. A total of 312 samples were collected from service station pumps in 20 cities throughout the United States. Of this number of samples, 207 were "com-petitive-price gasolines" and 106 were "premium-price motor fuels." All of the samples were collected in March, 1931, and analyzed at the Petroleum Experiment Station of the United States Bureau of Mines at Bartlesville, Okla. "Competitive-price gasoline" includes those fuels that are sold at the generally recognized local base price and all fuels that are sold below that price. All fuels that are sold at an advance over the generally recognized base price are placed in the class of "premium-price motor fuels." These fuels include Ethyl gasolines, benzol blends, "high-test" fuels, and those fuels that owe their "anti-knock" rating to the process of manufacture rather than to the addition of other material such as Ethyl fluid or benzol. The term "high-test" is generally applied to motor fuels that are more volatile than the regular competitive-price gasolines. "High-test" fuels may also have a high anti-knock rating.

Jan 1, 1931

By F. J. Palumbo

An electronic color-sorting machine was tested for recovering colorless glass concentrates from mixed glass products. The tests were made using glass recovered from unincinerated (raw) urban refuse and residues resulting from the incineration of refuse. The results of the study revealed that concentrates analyzing about 86 percent colorless glass could be recovered from mixed unincinerated glass containing 54 percent colorless glass material. Recovery of the colorless glass was about 62 percent. Color sorting the incinerated glass was somewhat more difficult. Multiple-stage processing was required to recover 59 percent of the colorless glass material in a product analyzing 89 percent colorless glass. The feed material analyzed 41 percent colorless glass.

Jan 1, 1971

By E. V. Potter

"INTRODUCTION The oscillator and amplifier system described in this paper was developed specifically for driving sound generators of the type developed by H. W. St. Clair and described by him in an article 3/ published several years ago in the Review of Scientific Instruments.Nevertheless, with little or no alteration it can be used to drive any vibrating system in which the vibrating member must be driven at its resonant frequency; the only restrictions are that the driving mechanism be electrical in nature and that the vibrating member be accessible so that some type of pick-up can be coupled to it. Operation of the automatic frequency-control element in the oscillator, however, depends entirely on the operating characteristics of the vibrating member; therefore, in order to completely explain the operation of the circuit, it will be necessary to describe the construction and operation of the vibrator used with it. Only the essential features and characteristics of the vibrator will be described in this article, and the reader is referred to St. Clair's 4/ report for further details."

May 1, 1943

By J. B. Gayle

A half-ton experimental coke oven was installed at the Southern Experiment Station, Tuscaloosa, Ala., in 1948. Designated as the Tuscaloosa oven, this unit features a 17-inch carbonizing chamber, globar heating elements, and silica-brick walls designed to simulate as closely as possible the carbonizing conditions for commercial, slot-type ovens. The reasons for constructing an oven of this Size, the details of the design, and the operating characteristics of the oven have been given in previous publications.3/4 The present report deals with the reproducibility of test-oven data and the effects of variations in flue temperature on the physical properties of the cokes produced. Also included are the results of 2,400° carbonizing tests for several coals and coal blends not included in the earlier reports.

Jan 1, 1955

By Paul M. Tyler

Calcium chloride is a conspicuous example of a former waste product that has found a place for itself in the onward march of civilization. Formerly considered a troublesome constituent of the effluent sewage of many chemical manufacturing plants and salt works, it has now become a commercial product of substantial importance, with sales aggregating almost six million dollars in 1929. The point has not yet been reached where it would seem profitable to undertake large-scale production of calcium chloride as a main product, but as a byproduct it has become an item that warrants serious consideration by all who are in a position to recover it at sufficiently low cost. The largely increased demand for bromine and for certain magnesium salts, which are likewise potential byproducts associated with calcium chloride in most salt-works bitterns (and brines generally), adds further impetus to commercial research directed toward the fuller utilization of the natural saline resources of the United States.

Jan 1, 1934

By A. E. Lindquist

This Bureau of Mines publication identifies areas having sufficient coal reserves to support synthetic natural gas (SNG) development and summarizes those areas having the highest potential. Capital requirements, mining and coal cost factors, water availability, and coal-quality data pertinent to SNG production are presented. Evaluation of individual coal reserve blocks was based upon coal and water requirements of the Bureau of Mines Synthane coal gasification process.

Jan 1, 1977

By R. B. Tippin

To study continuous operation of the heavy liquid separation (HLS) of minerals, the Bureau of Mines concentrated spodumene from a typical ore. The studies included heavy liquid concentration, removal of the heavy liquid from the mineral products, and recovery of the heavy liquid for reuse. The research program examined the influence of feed moisture, steam consumption, stripping time, and condition of steam. Operation of multiple cyclones in series resulted in spodumene concentrates assaying 92 to 95 percent spodumene and indicated mineral recoveries of 86 to 89 percent. Continuous filtration and steam stripping produced mineral products containing less than I pound of heavy liquid tetrabromoethane (TBE) per ton of material. Problems unique to this process are discussed, including heavy liquid properties and viscosity, toxicity, material handling hazards, and safety precautions.

Jan 1, 1970

By G. W. Jones

Among its investigations into the prevention of waste in production and use of oil and gas, the Bureau of dines has made considerable study of the efficient utilization of gasoline and by-product distillates in motors, this being done chiefly by measuring and analyzing the exhaust gases therefrom. A number of reports3 of a highly practical nature have been published and are available on this subject. The results of these tests have shown that the average motor vehicle wastes approximately 30 per cent of the heat value of the fuel used, as incomplete combustion products - carbon monoxide, hydrogen, and methane, These unnecessary large heat losses are mainly due to improper carburetor adjustment, and by proper¬ly adjusting the carburetors for maximum power and efficiency a large part of this heat loss can be eliminated. This in turn results in an increased mileage per gallon of fuel used.4

Jan 1, 1924

By Alfred L. Ransome

GOLD output in Alaska in 1950, following a 2-year decline, increased to the highest point since 1942. Tills unexpected gain in production of the Territory's greatest value commodity was largely responsible for the increase in the over-all value of mineral output in the Territory to $17,852,000 from $15,549,000 in 1949. Although coal continued to rank second to gold in value of output, production was slightly less than the record production of 1949. The mining of platinum continued to be an important factor in the mineral industry, with production of crude platinum metals exceeding that of 1949. The output of lead was three times the 1949 production, and silver gained 46 percent over the previous year's total. Copper and zinc production-entirely as byproducts from other ores-showed an increase, but remained minor. Production of tin was relatively small, but substantially above the total for 1949.

Jan 1, 1953

By Juel H. Stears

The bureau of Mines analyzed data from 47 coal mine roof-fall resupport accidents that occurred from 1966 through 1974 to identify critical hazards .and problems. These accidents resulted in 62 injuries or fatalities. It was concluded that the majority of the accidents might have been prevented by observance of recommended practices and use of available technology such as setting temporary supports, adequate roof testing, etc. Additional work is needed in the following problem areas where present technology is inadequate: (1) warning of impending roof falls shortly before they occur, (2) better methods of detecting unsafe roof and ribs, (3) providing access to and temporary support of high roofs for testing and bolting, (4) reducing the noise level of stopers, (7) developing temporary roof support; that have greater stability and can be remotely installed, and (6) reducing the number of roof falls through better permanent support.

Jan 1, 1976

By M. P. Board

The U.S. Bureau of Mines, under a cooperative agreement with Hecla Mining Co., conducted a rock mechanics study at four widely spaced horizons in a deep mine shaft in northern Idaho. The objective of the project was to measure and analyze rock deformation and lining behavior during construction of a deep shaft in a high in situ stress field within an isotropic rock mass. Rock mass displacements were monitored with multiple-position borehole extensometers. Liner stress and strain were measured with concrete pressure cells and embedment strain gauges. This report discusses the general trends and magnitudes of data from the four test sites, and relates the data to a proposed anisotropic constitutive model for the rock mass. A design procedure is then outlined for specifications of liner thickness and support installation sequences for future shaft sinking.

Jan 1, 1989

By Jim F. Lemons

The Bureau of Mines Minerals Availability System collected and analyzed data for 34 nonlaterite and 9 nickeliferous laterite domestic chromite deposits in order to assess their viability as sources of chromium under present technologic and economic conditions. These 43 deposits, none currently in production, contain approximately 6.3 and 22.3 million metric tons of Cr203 at the demonstrated and identified resource levels, respectively. Approximately 4.6 and 15.6 million metric tons of Cr203 are recoverable at the demonstrated and identified levels, respectively, for the 34 nonlaterite deposits. None of these resources are economically recoverable at January 1981 market prices. Production of metallurgical-grade chromite (market price $128 to $144) would require a minimum chromite market price of $237 per metric ton. Chemical-grade chromite production (market price $74 to $85) would require a chromite market price in excess of $188 per metric ton. From the 34 nonlaterite deposits, roughly 5.4 and 17.6 million metric tons of ferrochrome could be produced at the demonstrated and identified resource levels, respectively; however, a minimum market price of $770 per metric ton of ferrochrome would be required to stimulate production. The nine nickeliferous laterite deposits were not evaluated through production stages because of uncertainties in process technology and cost.

Jan 1, 1982

By H. B. Brunot

The United States Bureau of Mines under provisions of Schedule 2C4 issues approvals covering complete operating units such as loading machines, room hoists, and storage-battery locomotives. Certain manufacturers design and build entire machines. Other manufacturers purchase a part or all of the electrical accessories from manufacturers of electrical equipment and make up permissible units by assembling them. Before the assembler purchases electrical accessories for use in such contemplated units he may require certain information from the accessory manufacturer as to whether the particular accessories are suitable for assembly in his proposed permissible outfit. To aid accessory manufacturers in marketing their product, a provision was incorporated in Schedule 20 whereby tests might be made on individual accessories and reports rendered as to the suitability of a given accessory for use in permissible assemblies.

Jan 1, 1935

By E. L. Singleton

The electrochemical reduction of aluminum chloride to aluminum was investigated in a closed, two-compartment cell utilizing a molten chloride electrolyte. The externally heated cell was divided into a reduction compartment and a combination AICl3 feed and metal removal compartment. Aluminum was deposited at 700° C on a molten aluminum catbode from a KCI-NaCI-AICI3 electrolyte. The AICl3 content of the electrolyte was replenished by either vapor or solid additions. The chlorine evolved was collected and measured to give a quantitative evaluation of AICl3 reduction. The effects of anode and cathode current densities and AIC13 concentration on anode current efficiencies were studiedo A range of 64 to 84 percent anode current efficiency was obtained with the 25-pound electrolyte capacity cell and related auxiliary equipment.

Jan 1, 1968

By A. C. Fieldner, G. W. Jones

Tests were made at the Government Fuel Yard , operated at Washington , D. C. by the Bureau of Mines , Department of the Interior , in order to determine and improve the adjustment of the carburetors on the trucks used for transporting coal from the Fuel Yard to the different Government buildings in Washington . The tests were made possible through the hearty cooperation of G , S. Pope , engineer in charge of the Fuel Yard . Joseph Burrows and A. E. Foote of the garage department assisted during all the tests and supplied information on the mileage obtained by the trucks for the months preceding and succeding the time the tests were made . The Mack trucks used range in capacity from 2-1/2 to 7-1/2 ttoonnss .. The majority of the carburetors were Stromberg G- 3 type , as shown in Table 2. During the winter months , when the demand for coal is heavy , from 30 to 35 trucks are used . At the time the tests were made , only about ten of the trucks were in daily use , owing to the small demand for coal during the summer months , and scarcity due to labor conditions . Samples of the exhaust gas were taken on the trucks kept in service for summer hauling in order to determine the carburetor adjustment as used . Changes were then made to a more economical adjustment wherever possible , without sacrificing flexibility of operation and power . In every case the adjustments were maintained for maximum power , but were adjusted to the leanest position to give that power . In all but one case the carburetors were found to be adjusted too rich for maximum power and economy . These results are considered in detail in a later part of this report .

Jun 1, 1923

By Edward G. Cunney

Track in underground bituminous coal mines was investigated and technology was taken from other industries in order to obtain information on conditions that impair the safety and efficiency of the track and to develop guidelines and useful information on the construction, inspection and maintenance of mine track. Volume 1 contains information on the investigations, observed track conditions, useful technology from railroads and other industries, derivations of track condition descriptors and limits, conclusions, and recommendations. Volume 2, Guidelines, contains recommended standards and practices for mine track. It includes the relation of track conditions to safe speeds; descriptions and limits for measurable track features, such as gage; descriptions of conditions for track components that are normally not measurable, such as subbase soils; construction requirements and techniques; inspection requirements and methods; and methods for managing and performing track maintenance work. It does not repeat the summary or? derivations. Volume 3, Inspection Handbook, summarizes recommended standards and procedures from Volume II and provides related information for ready reference by inspectors in the mines. As a research product to be used in mines, it does not repeat the summary, derivations or references.

Jan 1, 1977

By Paul T. Allsman

The vanadiferous deposits of the Sublette Ridge and Salt River Range, 2 miles east of Raymond, Idaho, in western Lincoln County, Wyo., were examined August 24 to August 30, 1942, by an engineer of the Bureau of Mines, who was shown these properties by W. W. Rubey of the Geological Survey, Washington, D. C. The Sublette Ridge deposits are owned by the former U. S. Phosphate Co. H. F. Chaney, Portland, Oreg., is the representative for the company. The following report covers the history of the district, outlines the physical features and communications, mentions the property, and notes the ownership. The deposits and ore are described, and work performed by the Bureau of Mines is explained in detail. Ore-dressing tests and methods are explained.

Jan 1, 1949

By Gordon L. Kinney

The only economically important mineral currently produced in Bangladesh was natural gas. Bangladesh was not a world? ranked producer of any mineral commodity, but the possibility of producing and exporting commercial amounts of liquefied natural gas (LNG) was being examined. Proved reserves of natural gas were sufficient to supply most of the country's industrial and domestic heating and electric needs and still support an export-oriented LNG plant. Other mineral production was of virtually no significance to the economy, although there were a few prospects for nonmetallic mineral development. Bangladesh continued to make economic progress during 1978 and into early 1979. Gross domestic product (GDP) at current prices rose from $6.6 billion in 1976-772 to $8.2 billion in 1977?78 and $9.3 billion in 1978.79.2 In fiscal 1979, the economic conditions were favorable until a severe drought hit most of the country. It W88 reported that conditions were the worst in 40 years, and 88 of July 1979, substantial crop losses were predicted. The agricultural sector accounts for over 53% of the GDP and about 75% of all employment. The poor weather will cause economic problems in the form of slower growth, larger trade deficits, and a higher rate of inflation. The 1978.79 statistics showed that real GDP increased just 4%.

Jan 1, 1981