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By Daniel N. Tallman

To provide technology for achieving more efficient water filtration systems for the mineral industry, the Bureau of Mines performed demon-stration filtration tests at three iron ore mines and one steel mill. A comparison of equivalently sized magnesium oxide (MgO) and sand filters showed that MgO had a higher capacity and could operate at higher fil-tration rates than sand. In demonstration tests when alum (AlK(S04)2) was the coagulant, suspended solids breakthrough occurred even though the pressure across the filter (head loss) was 7 psig or less. Under these circumstances, the MgO demonstrated 20 to 100 pct greater filtra-tion capacity, defined in terms of the volume of water filtered before breakthrough. When an organic floccu1ant was used at one location, head loss was the run-limiting factor; the filters essentially plugged with-out any solids breakthrough.

Jan 1, 1985

By C. A. Rhoades

A major contributor to the problem of short life expectancy for blade-type conveyor belt cleaners is uneven wear along the blade edge. Uneven wear results in the formation of channels in the blade edge, which allow material to be carried back between the blade and the belt. In an effort to reduce the uneven wear problem, the U.S. Bureau of Mines has studied the mechanisms responsible for effective belt cleaning. From this study emerged a design for a cleaner blade that would greatly reduce uneven edge wear. The design consists of a standard cleaner blade incorporating air passages that allow for the expulsion of air along that part of the blade edge in contact with the conveyor belt surface. The results of 18-h tests indicated that the expulsion of air on the blade edge prevents scratches from developing into deep grooves. These tests showed that effective blade cleaning life can be extended 25 times using the pneumatic cleaning blade, compared with solid metal cleaning blades.

Jan 1, 1989

By Thomas E. Marshall, Roy H. Grau

The U.S. Bureau of Mines has developed an acoustic test for determining if a rock salt sample is from a "normal" nongassy salt face or from a gassy face where an outburst has the potential to occur. The test is based on the observation that a salt sample taken near an outburst-prone zone produces an audible popping sound when it is dissolved in water. The sound is produced when pressurized gas that is trapped in salt samples is released. In the acoustic test, the sound is electronically measured, digitized, and transmitted to a microcomputer; the output is an average decibel value that classifies the sample as "normal" or "outburst." The acoustic test procedure and equipment are described, and raw test results and data analysis are shown. Results are also shown for several salt samples that were analyzed using a laser Raman microprobe.

Jan 1, 1990

By Manuel Gomez

Areal distributions for ash, total sulfur, and sulfur forms were developed for the top 12 inches, the middle section, the bottom 8 inches, and the total seam of Pittsburgh coal in southwestern Pennsylvania. The sulfur and ash exhibit an apparent high local variability. As a general rule, both the sulfur and ash show high concentrations in the top 12 inches and in the bottom 8 inches of the seam relative to the concentrations observed in the middle section of the seam. The high-low sulfur and ash concentrations in the top 12 inches of the seam are not coincident with the high-low sulfur and ash concentrations in either the middle section or the bottom 8 inches of the seam. With respect to sulfur and ash, it is suggested that the top and bottom sections of the Pittsburgh coal may reflect both a syngenetic and epigenetic origin. Present data support the belief that paleotopography controlled Pittsburgh seam deposition. Evidence is presented to show that channels were cut at various times into the semilithified sediments that buried the Pittsburgh seam. In this channeling process, portions of the Pittsburgh coal may have been eroded away. Following channel development, the lower part of the Pittsburgh sandstone filled the complex system of braided channels to produce the "want areas" encountered in present mining operations. In localized areas of the Pittsburgh seam, impingement of Pittsburgh sandstone may be responsible for the lateral displacement of the coal. Information of this type becomes important in the assessment of exploration data, in the development of a quality control system for mine output, and in mine life planning.

Jan 1, 1974

Flexible hoses with rated working pressures up to 40,000 psi are used when high-pressure water jets are employed to cut rock or improve the performance of mining machines. Hose failures at such high pressures can result in serious injuries to workers. The Bureau of Mines used fatigue and burst tests to investigate the failure modes of high-pressure hoses at their rated working and burst pressures. Fatigue failure, at rated working pressures, occurred when the inner liner of the high-pressure hose broke, allowing water to seep through the wire wrapping, although the reinforcement wires did not break. At the burst pressure, all hoses failed catastrophically when the reinforcement wires broke. Low-pressure hoses placed over the high- pressure hoses for safety failed to contain water released by catastrophic failure.

Jan 1, 1987

CESIUM metal production increased sharply in 1963. Domestic Production.--Cesium metal was produced by The Dow Chemical Co., Midland, Mich., MSA. Research Corp., Callery, Pa., and by Penn Rare Metals, Inc., Revere, Pa. American Potash & Chemical Corp., Trona, Calif., produced some combined cesium and rubidium. This company, Penn Rare Metals, Inc., and Rocky Mountain Research, Inc., Denver, Colo., produced various cesium compounds. Complete production data on cesium and rubidium and their compounds were not available for publication. Consumption and Uses.-Substantially more pollucite was consumed to produce cesium metal and compounds in 1963 than in 1962 but the overall consumption of pollucite continued to be small.

Jan 1, 1964

By Henry M. Harris

The Bureau of Mines investigated a glass containing approximately 17 percent lithia and 83 percent silica to establish a method of devitrifying cast and rolled shapes. Glass shapes with high strength were made by melting, forming, and rapid cooling of the composition, and the shapes subsequently were converted to a crystalline condition by heat treatment. The best devitrification schedule included rapid cooling of the glass to below 300° C, followed by reheating at a rate of 50° to 400° C per hour, depending on the size of the shape, followed by a of 60 to 70 hours at 500° C and another period of 15 hours at 800° C. attempts to use faster heating rates or slow cooling to accomplish devitrification in deformation of the shapes. The crystalline shapes had flexural strengths that averaged over 33,000 psi, achieved with an annealing time of 60 to 70 hours at 500° C.

Jan 1, 1965

By F. N. Kissell, R. J. Bielicki

The Bureau of Mines found sulfur hexafluoride (SF6), released from a lecture bottle, to be an ideal gaseous tracer for studying mine ventilation systems. Air samples were collected in glass syringes and analyzed by electron-capture gas chromatography. In these studies, the lower limit of detection was about 1 part per billion by volume (ppb) of SF6 per part of air. Experiments conducted in a Pennsylvania limestone mine showed this technique useful in evaluating the effectiveness of auxiliary fans, measuring low flow velocities, probing the air circulating near a working face region where ventilation appeared to be poor, and estimating volumetric flow rates in airways of large cross-sectional area and having low flow velocities. This technique was also used in a western vein-type metal mine to measure the amount of return air being recirculated into the intake air due to leakage through old stoped areas.

Jan 1, 1974

By H. C. Howarth

The preliminary tests referred to in this report wore made at the Bureau's Experimental Mine under the general supervision of G. S. Rice chief mining engineer, to determine whether rock dust way be used to extinguish or control mine fires. DESCRIPTION OF THE DUST USED The dust used for application by hand was made from draw slate taken from the Experimental Mine. This draw slate was crushed in a hammer-type crusher fitted with 1/16 inch by 2-inch slotted screens. A sizing test of the dust showed 96.5 per cent through 20 mesh, 69.4 per cent through 48 mesh, 46.2 per cent through 100 mesh, end 33.5 per cent through 200 mesh.

Jan 1, 1927

By E. R. Bauer

The U.S. Bureau of Mines is investigating strata interactions associated with mining of multiple coal beds to provide the mining industry with improved methods of planning and developing multiple coalbeds, conserving resources, and increasing the safety of underground coal mining. This study involves analytical predictions and underground observations of longwall development ground control problems at a south-central Pennsylvania coal mine affected by subsidence induced by multiple-seam mining. As predicted, strata interactions were found in upper mine areas mined over lower mine gob. Observations revealed roof deterioration accompanied by excessive water inflows in the first 170 ft after crossing the gob line as mining entered and exited the subsided area (over the lower mine gob). In contrast, superimposed mine areas and areas mined a substantial distance out over the gob showed no signs of interaction with previous lower seam mining, again as predicted.

Jan 1, 2010

By J. B. Gayle

Numerous investigators have studied the addition of inert4 substances to coking blends. Generally, the results have yielded trends applicable only to the particular coals and inerts studied. Recently, somewhat more general results were obtained for cokes produced from blends containing added inerts, using the sole-heated oven. The present investigation represents an extension of this work to include a wider range of inerts and to determine the applicability of the various conclusions to cokes produced with the Tuscaloosa oven. The results indicated that an increase in dry-coal charge density of 1 pound per cubic foot (p.c.f.) caused a corresponding change in the hardness (1/4-inch tumbler index) of Tuscaloosa oven cokes of 0.9 percentage points. This value compares favorably with the value of 0.7 determined previously for the sole-heated oven and Bureau of Mines-American Gas Association (BM-AGA) retort.

Jan 1, 1961

By T. E. Gray

This report describes the preparation characteristics of the more significant coal beds in Washington County, Pa. It is one of a series planned to determine coals suitable for producing metallurgical coke, either as mined or after beneficiation. More than 15 million tons of coal was produced in Washington County in 1956; 89.8 percent was cleaned mechanically in 10 cleaning plants. The Bureau of Mines has estimated that 2,280 million tons of recoverable coal remained in beds 28 inches thick or more as of January 1, 1954.

Jan 1, 1959

By A. L. Engel

Included in the program of the Rare and Precious Metals Station, Metallurgical Division, Bureau of Mines at Reno, Nev., are investigations of treatment methods for ores representative of various mining districts throughout the country. The samples received for this work may come from areas only recently explored or from newly discovered ore deposits in older mining districts. The present investigation deals with a case of the latter type, the. ample having come from a section that has a past record of considerable precious. metals production. The application of current treatment methods to this type of ore seems to offer excellent possibilities of satisfactory economic results. Definite identification of the silver mineral in this ore asthe chloride cerargyrite, AgCl, adds considerable interest to, the investigation, as in many cases where silver occurs in comparatively small amounts in an ore it is not possible to identify the particular mineral carrying the silver or else it is contained in or combined with other more common minerals. Cerargyrite is the "horn silver" of the bananza period and is mentioned in many accounts of pioneer mining of high-grade ores The occurrence of this mineral in finely disseminated form it a low-grade ore is believed to be unusual. The sample investigated was obtained from the' Bullfrog District neat Beatty, southwest Nye County, Nevada. The ore contained 16.7 ounces of silver per ton of ore, 0.007 ounce gold, and 0.32 percent copper in a silicious gangue, with accessory minerals, including iron oxides and scorodite; the hydrous iron arsenate.

Jan 1, 1949

By M. D. Marshall

This handbook is for the engineer or person responsible for the storage and removal of material from bins and silos in the minerals industry. The objective of the handbook is to prevent bin-related accidents by eliminating problems which require workers to enter bins. It provides basic information on handling materials so that knowledgeable decisions can be made on bin design and accessories to minimize flow stoppages. Materials are classified in terms of their flowability, and bin design and accessories suggested for each classification. A method for classifying a material is also given, and the various types of material flow aids reviewed. Safety around bins is the basic theme of the handbook. Federal regulations are reviewed and additional suggestions presented to prevent bin accidents. New equipment for releasing material hang-ups is reviewed.

Jan 1, 1984

By David P. Lindroth

The heat content above 25.0° C up to 1,000° C was measured for six rock types: St. Cloud Gray Granodiorite, Holston Limestone, Sioux Quartzite, Rockville Quartz Monzonite, Salem Limestone, and the basalt at Dresser, Wis. The calorimetric data were obtained with an isothermal jacket-copper block calorimeter. The experimental heat content data for each rock type are presented, along with specific heat data obtained from the temperature derivative of the heat content. For the six rock types the maximum deviations of the specific heats at a given temperature were within 10 percent below 575° C and within 34 percent above 5750°C. The increase in the values of specific heat range from a minimum of 13 percent for the basalt at Dresser, Wis. (temperature range, 100° to 1,000° C) to a maximum of 46 percent for Holston Limestone (temperature range, 100° to 870° C).

Jan 1, 1971

By R. E. Perry

In connection with a program of coal research at the Southern Experiment Station the Bureau of Mines, in cooperation with the University of Alabama and the various coal operators, conducts washability studies of coal from beds in Alabama and other Southern States in which commercially important deposits occur. One of the main objectives of a washability study is to obtain technically and commercially important data necessary for determining the best methods for preparing and utilizing the Nation's limited reserves of coking coal. Such information is important to conservation because it facilitates selection of preparation methods that will provide maximum yields of coal with low ash and sulfur contents.

Jan 1, 1958

By R. C. Hickman

"INTRODUCTION The most productive area of the eastern Virginia pyrite belt lies to the north of the village of Mineral., in Louisa County. The largest producers of pyrite ore in the area were the Armenius, Boyd Smith, and the Sulphur mines.The Boyd Smith mine started production about 1890 and operated more or less continuously until 1922, when competition from the Gulf States and Spain closed the pyrite mines in Virginia. There are no reliable records of production or value of minerals produced.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the most effective utilization of our mineral resources to the end that they take the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, Oliver C. Palston, chief, analyzes samples and performs beneficiation tests.The project was under the immediate supervision of Mitchell H. Kline, chief, Raleigh Division, Mining Branch, Bureau of Mines.LOCATIONThe Boyd Smith property is reached from Mineral, Va., by traveling north on State Route 522 about 2-1/2 miles. An unsurfaced road, winding in a northwesterly direction, loads to the Boyd Smith headframe, which is about half a mile from State Route 522 (fig. 1). The tract comprises 181 acres."

Aug 1, 1947

By U. E. Brown

This papery describing the mining methods employed by the Bunker Hill and Sullivan Mining and Concentrating Co. at Kellogg, Idaho, is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the United States. The Bunker Hill and Sullivan mines are situated in the western part of the Coeur d'Alene district at Kellogg, Shoshone County, Idaho. The mines were discovered during the summer of 1885 and except for two short periods of labor trouble, between 1890 and 1900, have been in continuous operation. About 575 men are employed at the mine. The production is about 1,400 tons of lead-silver ore per day. This is treated in the company's concentrator and smelter at Kellogg.

Jan 1, 1931

By B. W. Gandrud

In the summer of 1950, Bureau of Mines engineers visited a number of coal-preparation plants in western Europe and Great Britain to obtain information on European and British coal-cleaning and froth-flotation practices. In view of the growing importance of froth flotation as a process for cleaning fine sizes of coal, it was felt that such data and information would be of value in this country, for, although froth flotation has been adopted for use in a few of our plants, it has not as yet been employed as extensively as in British and European preparation plants. Many of the important coal beds in western Europe, especially in the Ruhr Valley of Germany and in the Dutch coal-mining region of Limburg, Netherlands, are very friable, with the result that the run-of-mine product contains a large proportion of the sizes too fine to be treated successfully by any other method than froth flotation. Furthermore, the relatively high cost of producing coal from these beds has for many years made it economically feasible and desirable to treat the fines by froth flotation, especially in the coking-coal fields.

Jan 1, 1951

By C. M. McCulloch

A series of geological surveys were completed in six coal mines in connection with a Bureau of Mines research program on methane control. The aim of these surveys was twofold: First, to study the overall geology of the coalbed, and second to use the resulting data to evaluate the influence of the geological characteristics of the coalbed on safe and efficient coal extraction. This report explains the advantages of geologic maps and fence diagrams in coal mining, and how the knowledge gained from such geologic investigations of mines can help control many underground problems.

Jan 1, 1975