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By E. B. Kester

A study of the composition of the corresponding fractions of a primary and a high- temperature tar was undertaken to throw light on the net results of the pyrolysis of the primary products of coal decomposition in high-temperature coking practice, with reference both to total quantities of the chemically similar constituents and to their distribution throughout the boiling range. No exactly parallel investigations are on record. The distribution of substances in high-temperature tars, however, is fairly well understood. Such tars are more or less similar, for they consist of the more stable phenols, aromatic and olefinic compounds resulting from the pyrolytic decomposition of a wide variety of primary tar constituents. For example, from a typical distillation curve for high-temperature tar phenols4 it may be seen that the greatest portion of the phenols distills between 180° and 220° C., a fairly narrow range.

Jan 1, 1932

By Jon K. Ahlness

The Bureau of Mines investigated technologies for testing the integrity of in situ leach mining wells, as required by environmental regulations. To test for leaks, inflatable packers were used to seal the well casing. Laboratory testing determined that the packers could contain a casing pressure up to 50 to 60 psi (345 to 414 kPa) less than the packer inflation pressure. Single-and double-packer configurations were successfully field-tested in 32 wells ranging from 500 to 530 ft (153 to 162 m) in depth. A rigid pipeline and a hoist truck were used to run the packers in and out of the wells for the double-packer tests, which averaged 2-1/4 h each. In an effort to decrease the time of the rigid-pipe double-packer test. a self-contained trailer-mounted test system was designed and built. It utilizes a winch and steel cable to run the packers in and out of the well and high-pressure nylon tubing for packer inflation. This system was successfully field-tested in eight wells averaging 650 ft (198 m) in depth and resulted in a time savings of 13 pct and an operator-hour reduction of 42 pct.

Jan 1, 1985

By E. P. Youngman

Zirconium, formerly distinctly a rare element, is rapidly becom- ing of rather extensive commercial importance. Economic features of the zirconium industry, together with general information regarding the metal and its compounds, are discussed in a separate paper, to which this paper is a supplement. In addition to giving a brief discussion of the four or five de- posits that so far have proved to be commercial sources of the element, this circular summarizes available data (including some hitherto unpub lished material from the files of the Bureau of Mines) upon other occur- rences, including many of scientific interest only, of the two commercial. minerals, zircon and baddeleyite, and also data upon some of the minor minerals, such as eudyalite and cyrtolite, which have attracted addition- al interest in recent years because they are frequently richer in hafnium than the more common zirconium minerals.

Jun 1, 1931

By A. M. Evans

Because of an urgent national need for manganese, the deposits in the Little Florida Mountains of Lune County N. Mex., were visited by O.H. Metzger, an engineer of the Bureau of Mines, on June 12 and 13, 1940, accompanied on the second day by S. G. Lasky, a geologist of the Federal Geological Survey. After this preliminary examination, it was recommended that exploratory work be done by the Bureau of Mines on several properties in the district. An exploratory project of trenching, sampling, and core drilling was started by the Bureau of Mines in September 1940 and completed in May 1941.2/ Work was done on three properties - the Luna mine, the American group of claims, and the Manganese Valley mine. The Little Florida manganese district is situated on the eastern slope of the Little Florida Mountains about 2 miles south of U. S. Highway 80-90, 12 to 14 miles southeast of Deming, Luna County, N. Mex. The principal claims comprise the Luna Manganese, American, and Manganese Valley groups.

Jan 1, 1949

By James F. Devine

This Bureau of Mines report describes tests conducted at three sites to determine if, and to what extent, a vertical presplit fracture plane placed between a blast point and detection point will reduce vibration levels. Statistical analyses indicate that the presplit fracture plane did not reduce the vibration level.

Jan 1, 1965

By Robert M. Doerr

Isothermal oxidation kinetics were determined for three grades of Ni and for 99.99 percent Co in Ca and in air from 800° to 1,200° C. The oxidation reactions followed approximately the parabolic rate law. For 99.99 percent Ni in 02 at 1,200° C, the parabolic rate constant was 2 mg cm-2 hr-2. For 99.99 percent Co in dry air, the constant ranged from 1 mg cm-2 hr-2 at 800° C to 18 mg cm-2 hr-2 at 1,200° C; for 99.99 percent Co in 02 the constant was 2 mg cm -2 hr-2 at 800° C and 10 mg cm-2 hr-2 at 1,000° C. For 99 percent Ni in dry air, the constant ranged from 0.2 mg cm 2 hr-2 at 800° C to 3 mg cm 2 hr-2 at 1,200° C. By X-ray diffraction measurements, only divalent oxides were found in the scales. Volumetric and quartz-helix gravimetric methods were used. The volumetric apparatus was designed to permit less stringent restrictions on the corrosion specimens; it was also more convenient to use. The agreement between the weight gain determined gravimetrically and the 02 consumption determined volumetrically was not good enough for direct comparison of gravimetric and volumetric results.

Jan 1, 1963

By C. H. Schack

Although viscosity is known to be important in processing and handling finely ground urea, its effect has never been fully quantified. This report describes the methods used and the results obtained in the initial phases of a broad investigation of the influence of viscosity of water suspensions of minerals in flotation, thickening, filtering, and other mineral-dressing unit operations. Several types of vis-cosimeters were tested before reliable and reproducible results could be obtained on mineral suspensions. After the viscosimeter used in the research was calibrated and standardized, tests were made on six pure minerals to study the relationship of pulp density, particle size, crystallinity, and cleavage on viscosity. An orifice-type viscosimeter equipped with a mechanical stirrer gave as good results as other types and was more flexible, faster, and simpler to operate. The orifice-type viscosimeter, when calibrated and standardized with glycerin and water mixtures, proved satisfactory over a wide range of viscosities. The accuracy and reproducibility were reasonably constant between 1 centipoise and 200 centipoises, the anticipated range in common mineral-dressing unit operations.

Jan 1, 1957

By C. W. Morris

This Final Report describes the major technical activities that were accomplished to produce a comprehensive continuous miner training system (CMTS) for coal industry utilization. The primary product of this program was a continuous miner part-task trainer. It is composed of an interactive computer graphics system combined with the operating controls of a continuous mining machine mounted in a simulated cab. The cab contains an audio system for reproducing continuous miner operational sounds. The trainer is supplemented with a complete set of cognitive materials that provide instruction in the operation, safety and health of continuous miner operations. A complete summary of the field test and evaluation of the CMTS is provided along with a set of recommendations for further training program refinements, expansions, and utilization.

Jan 1, 1982

By John Neil, John Bli ard

Coke breeze consists of the smaller particles of coke formed by handling coke on and after removal from the ovens. Its value as F, fuel is less than that of the larger pieces, both because the smaller pieces contain more ash and therefore have a lower calorific value, and because a greater draft is required to burn it.The tests described below show its value as a fuel when mixed with bituminous coal and burned in a hand fired boiler of a size considerably greater than that used in an ordinary house. The results of these tests, however, can be used to give a fairly good indication of the value of coke breeze when burned with bituminous coal in a domestic furnace.All who fire a domestic furnace know that for only a comparatively short part of the day, and then only on a few days, is it necessary to open fully the ash, pit door and stack damper to get the required rate of combustion in the average furnace in the average house. It will be practical, therefore, during the greater part of the heating season, to fire coke breeze with the coal and use more of the available draftsFor domestic heating the coke breeze should be stored separately, and used when the draft is sufficient to burn it in mixture with bituminous coal, at the rate required to warm the house.Purpose of tests: The tests were carried out at the request of the Chamber of Commerce of Pittsburgh, Pa., in order to determine the steaming value of coke breeze as a fuel when mired with Pittsburgh coal and fired by hand, and to see whether the mixture when burnt would give off an objectionable quantity of make.

May 1, 1921

[Early in 1936 the Interstate Oil Compact Commission and other groups interested in forecasts of demand .for petroleum requested the Bureau of Mines to make a physical inventory of crude-oil stocks in the United States. Accordingly, the 74th Congress appropriated funds for conducting such a survey during the fiscal year ended June 30, 1937. In the discussions and hearing2/ relative to the need for the sway, the opinion ms expressed that crude oil held in storage for long periods had lost so much of its gasoline content that he economic significant of total stocks should be discounted materially. Therefore, a primary objective of the survey was to]

Jan 1, 1938

Early in 1936 the Interstate Oil Compact Commission and other groups interested in forecasts of demand for petroleum requested the Bureau of Mines to make a physical inventory of crude-oil stocks in the United States. Accordingly, the 74th Congress -appropriated funds for conducting such a survey during the fiscal year ended June 30, 1937. In the discussions end hearings2/ relative to the need for the survey, the opinion was expressed that crude oil held is storage for long periods had lost so much of its gasoline content that the economic significance of total stocks should be discounted materially. Therefore, a primary objective of the survey was to

Jan 1, 1938

By J. Mitchell Linnet

Bureau of Mines personnel examined mines, prospects, and mineralized areas to determine the mineral resources and potential of deposits in the Bucks Lake and Chips Creek RARE II areas in Plumas and Butte Counties, California. These areas lie along the west slope of the Sierra Nevada on opposite sides of the North Fork Feather River and encompass an area of 62,800 acres (25,400 ha). Metasedimentary and metavolcanic rocks of the Pennsylvanian Calaveras Formation are intruded by plutons of Mesozoic age. Mineral; of economic iterest are in quartz veins in metasediments close to these plutons; they are principally gold and silver with minor amounts of copper, lead, and zinc minerals. Molybdenum, copper, silver, and tungsten minerals occur in tactite along metasedimentary-granitic rock contacts. In both areas, auriferous Tertiary channel gravels have been extensively developed. Asbestos occurs in ultramafic rocks in both areas, and a limestone deposit was explored in the Chips Creek area. Gold is the principal economic mineral in the Bucks Lake RARE II area. The Shenandoah Mine (fig. 1, no. 19) contains 7,500 tons (6,800 t) of indicated and inferred subeconomic gold resources in sulfide-bearing, silicified metamorphic rocks of the Calaveras Formation (table 1). Similar rocks have yielded gold at the Edman and Megowen Mines, adjacent to the area. A high potential exists for additional lode resources in the area around the Shenandoah Mine. Callahan Mining Corporation personnel believe a multi-million ton disseminated gold deposit underlies the property.

Jan 1, 1983

By F. L. Wideman

This report describes a computer program that is used for the calculation of the coordinates and elevations of subsidence survey pins located by intersection. This program was developed for the Federal Bureau of Mines by the Numerical Analysis Laboratory, University of Arizona. These calculations, although relatively simple, are both tedious and time-consuming when computed with a desk calculator and trigonometric tables. In this survey, a large number of pins were surveyed repeatedly, and it was evident that both time and money could be saved by using a digital computer.

Jan 1, 1962

By D. E. Pollock, J. A. Organiscak

Water sprays and water powered scrubbers have both been utilized in the mining and milling industry to suppress airborne dust. Unconfined water sprays operated at lower water pressures of ?689 kPa (?100 psig) can be very effective at wetting the mine product at the dust source and significantly reducing the amount of respirable dust that becomes airborne. However, unconfined waters sprays can be somewhat ineffective in actually removing airborne dust from the air. On the other hand, water powered scrubbers operating at higher water pressures of ?1,724 kPa (?250 psig) in physical enclosures or ducts have previously been demonstrated to be very effective in removing airborne dust from the air. These higher operating water pressures are uncommon in many mines and mills, so their use is limited. The National Institute for Occupational Safety and Health (NIOSH) recently investigated the performance of a lower-pressure, water powered inline series spray scrubber for removing localized airborne dust emitted at the source. Results showed noticeable improvements in airborne dust capture efficiency through the operation o f multiple inline series hollow cone spray nozzles within a round duct or pipe at the same water pressure as a single spray. Operating hollow cone spray(s) at higher water pressures noticeably improved airflow through the scrubber and yielded some additional scrubber efficiency improvements. Thus, in-line spray scrubber efficiency trade-offs were observed to be made by altering spray power components of water pressure and/or quantity (number of sprays). Results show that, on average, up to 0.23 and 0.32 m3/s (484 and 679 cu ft per min) of airflow at 0.81 and 0.69 dust capture efficiencies can be achieved with three 81° and 33°hollow cone inline series sprays, respectively, operating at 1,655 kPa (240 psig).

By E. J. Gleim

A list of permissible mine equipment, tested and approved by the Bureau of Mines previous to January 1, 1942, was published in Bureau of Mines Information Circular 7207.3/ The list of that date was complete as to equipment then available and in current use. Information Circular 7240,4/ published as a supplement thereto, listed equipment approved curing the calendar year 1943. The present list is another supplement covering approvals issued during the calendar year 1943. The items are numbered to indicate the consecutive order in which each type of machine or device was approved in its particular classification. Thus, Information Circular 7207 gave 19 drills and drilling machines on the Bureau's active list. No additional approvals were given in 1942, but the three issued in 1943 bring the total to 22. Item 102, under Loading Machines and Conveyors, also appeared in Information Circular 7207, and items 120 and 124 appeared in Information Circular 7240. These numbers are repeated here to show that approvals were granted during 1943 for additional voltages on machines previously listed for one voltage only. Equipment listed in these circulars is approved by the Bureau of Mines only when found upon inspection and test to comply with minimum standards of safety as outlined in schedules prepared on the basis of many years of experience in dealing with safety problems of the coal-mining industry. The use of such equipment in mines known to be gassy, as well as in those that may become so, is earnestly recommended in the interests of safety. This circular is published so that the industry may be kept

Jan 1, 1944

The principal activities of the Bureau of Mines Explosives Research Center (now Safety Research Center) during fiscal year 1968 (July 1, 1967, to June 30, 1968) are reviewed in part 1. Part 2 presents short abstracts of the publications issued during this period in the Bureau series and in other media. Part 3 describes a short study on the thermal decomposition of RDX and HMX not destined for publication elsewhere. ACKNOWLEDGMENTS The Bureau gratefully acknowledges the support received through cooperative agreement in fiscal year 1968 from The Manufacturing Chemists Association.

Jan 1, 1970

By H. M. Harris

The Bureau of Mines investigated chlorination of domestic ilmenites in a fluidized coke bed at temperatures of 950° to 1,150° C. Objectives were to develop an effective process for producing TiC14 suitable for TiO2 pigment and to reduce pollution by collecting and treating waste byproduct chlorides. The reactor for these tests was a 10.2-cm-diam quartz tube heated externally by electrical resistance heaters. It contained coke beds of from 35.6 to 82.5 cm in depth that were fluidized by 13 to 25 l/min of chlorine. Ilmenite concentrate powders were introduced at the bottom of the fluid-bed reactor, using the chlorine gas stream as a carrier. Test results showed that greater than 90 pct of the ilmenite reacted at optimum conditions and recovery of TiC14 ranged from 95 to 99 pct of stoichiometric. A temperature-controlled cyclone was used to remove high-boiling-point chlorides such as MnCl2, MgCl2, and FeCl2, and also collected fine unreacted ilmenite and coke dust. Impure TiC14 and FeC13 were separated by collecting the, iron chloride in a condenser con-trolled at 200° C. Titanium tetrachloride vapor was cleaned by passage-through a salt-column filter followed by condensation in water-cooled and refrigerated condensers. Liquid TiC14 was purified further by well-known industrial methods to meet specifications for pigment-grade chloride. Integrated tests were conducted in which chlorine, produced by dechlorination of FeC13 with oxygen, was recycled and used directly in a fluidized-bed chlorinator.

Jan 1, 1976

By Dwight L. Sawyer, Roy T. Sorensen

The Bureau of Mines has investigated the recovery of alumina by hydrochloric acid leaching of calcined kaolinitic clay . Bench- scale studies indicated that horizontal belt filtration was a pprraaccttiiccaall method for separating the siliceous residue from aluminum chloride liquor generated in the leaching step . Miniplant -scale continuous testing was performed to evaluate the filter circuits and to compare filtration response of different calcined kaolin feed materials and of different agitatorbaffle designs in the leaching reactors . Soluble alumina recovery with a single filter ranged from 94 pct with minus 10 -mesh feed more than 96 pct with minus 35-mesh or misted feed . Process advantages were confirmed for the calcined misted kaolin feed material prepared by a Bureau-developed misting process . With two filters in series , an overall filtration rate of 100 lb solids /hr.ft - 2 of filter area was attained with a soluble alumina recovery of more than 99 pct . More than 99.5 pct alumina recovery was obtained with a thickener and a two - filter circuit for either the minus 35-mesh or the misted feed . Modifications in leaching reactor design made to decrease particle- toparticle attrition were successful and significantly increased filtration rates and decreased flocculant requirements .

Jan 1, 1965

By Lung Cheng

Based on earlier tests that showed steel to be much more likely to cause frictional ignition than tungsten carbide, the Bureau of Mines redesigned coal-cutting bits to reduce the hazard of face ignitions. Two bit designs--a mushroom-shaped bit with a conical shank and a dove-tail bit with a rectangular shank--are described, as well as bit wear tests conducted in the laboratory and in an operating coal mine. In laboratory tests, for 1/8-, 1/4-, and 1/2-in-deep cuts and cutting speeds of 280, 500, and 660 ft/min, the mushroom bit had significantly longer tip wear life than the conventional bit; the dovetail bit was also superior to the conventional bit. Results of in-mine tests on the mushroom bit agree well with laboratory results. In-mine tests of the dovetail bit are underway.

Jan 1, 1983

By D. E. Traut

A fluidized countercurrent ion-exchange system was developed, operated, and evaluated by the U.S. Department of the Interior, Bureau of Mines. The system consisted of integrated multiple-compartment absorption and elution columns in which the solution flows were continuous except for short periods when resin increments were withdrawn. The exchange of uranyl carbonate between a simulated in situ uranium leach liquor and a strong-base ion-exchange resin together with the subsequent elution with an ammonium chloride solution was studied. The effects of the number of sections, section height, amount of resin withdrawal, solution flow rate, and column diameter were investigated. The kinetic and equilibrium relationships for the absorption and elution steps were also examined. The experimental data indicate a strong interdependence between variables. Solution retention time appears to be a major limiting variable in the absorption process, while resin residence time is the determining factor in the elution process. The column was efficient over a range of conditions, but close control was needed for optimum operation.

Jan 1, 1978