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By Margaret R. Egan

This Bureau of Mines report presents results from experimental studies on wood crib fires in an intermediate-scale fire tunnel. Gas concentrations, smoke particle characteristics, heat release rates, and ventilation rates were determined. These measurements form a data base for wood, which can be used with previous analyses for coal and future studies of other mine combustibles, to comprehend the potential hazards of these materials in underground mine fires. A knowledge of the combustion products emitted from these materials will benefit fire detection and control. Results show the changes in burning rate and heat release rate produced by different crib configurations and ventilation rates. Also included are the effects that the burning rate has on smoke characteristics and gas production.

Jan 1, 1986

By M. J. Kovalik

Lower Sunnyside seam coal from Utah was blended with various proportions of char and high-temperature coke to improve the quality of the coke obtained from carbonizing this coal. The Hanson 5-pound carbonizer was used as a "screening test" for the larger scale Bureau of Mines-American Gas Association (BM-AGA) tests, which were correlated with industrial production. Eighteen carbonization tests were made in the BM-AGA 13-inch retort, with a coal charge of about 90 pounds; the cokes were evaluated by the standard ASTM tumbler test. Carbonization of blends containing char and coke breeze yielded less fissured and blockier cokes of significantly higher ASTM I-inch tumbler indices as compared with the value for the straight Sunnyside coal. It was found that the simultaneous addition of char and coke breeze yielded stronger cokes than that obtained by the addition of either one of these additives. Addition of a small proportion of Pocahontas No. 3 or Sewell coal to an optimum blend improved the resulting coke strength further.

Jan 1, 1969

By John W. Buch

In 1947, a Korfmann universal shearing machine was installed in a mine in the Southern field of the Pennsylvania anthracite region. The machine was obtained from Germany by the Bureau of Mines after the close of World War II as a part of a program of experimental work to increase the output and lower the cost of anthracite, which the Bureau of Mines initiated in 1944 when an agreement was made with an anthracite-producing company for use of one of the company's mines as a testing ground for certain mechanical equipment procured or developed by the Bureau. A major objective is to develop a mechanical mining method that will increase the rate of advance and reduce the coat of development of coal gangways in steeply pitching seams. In addition to the time to be saved in driving these openings by machine, it is felt that further economies will be affected by making it possible to concentrate producing sections into smaller compass and that savings will ensue in supervision, maintenance, and time required for mining a section. A higher percentage extraction also is an objective. Test work covered by this report was concentrated on the power characteristics, maneuverability, effectiveness, and general qualities of the Korfmann machine in cutting coal, the cutting tests representing the first use of a machine of this kind in steep-pitch mining in the United States.

Jan 1, 1951

By T. F. Mitchell, J. A. McAllister, S. J. Hussey

"INTRODUCTION During the Bureau's extensive program of investigating possible domestic sources of manganese, an are-dressing study was conducted in its laboratories at Salt Lake City, Utah, on a sample of oxide manganese ore representative of vein material from the Ophir Hill mine at Ophir, Tooele County, Utah. The sample (obtained by blasting down and mixing a portion of the vein) was submitted by the Ophir Development Co. of Ophir, Utah. As the ore was too law in grade to be acceptable for direct production of ferromanganese, it was tested to determine its amenability to concentration by ore-dressing methods.At the beginning of the investigation of manganese-ore beneficiation in December 1940, the only product marketable to Metals Reserve Company was ferrograde manganese, grade B, the requirements for which follow: Mn, min., 48 percent; Fe, max., 7 percent; Si02, max., 10 percent; P, max., 0.18 percent; A1203, max., 6 percent; Zn, max., 1 percent.Later, the specifications were modified gradually. As of May 15, 1943, manganese products were acceptable if they contained over 35 percent manganese and less than 3 percent zinc and 1 percent phosphorus. Prices were based upon material containing 48 percent manganese, 6.0 percent iron, and 11 percent silica plus alumina. Premium were paid for manganese content in excess of, 48 percent and iron content below 6 percent, penalties being imposed upon products containing less than 48 percent manganese or more than 6 percent iron or more than 11 percent silica plus alumina. The specifications for commercial manganese further required that maximum particle size be 12 inches and that 75 percent of the product be coarser than 20-mesh. Therefore, fine material, such as table and flotation concentrates, had to be nodulized or sintered. In addition, carbonate manganese ores were not acceptable unless calcined."

Oct 1, 1947

By H. P. Hamlin, W. A. Grosh

Samples of clays , shales , and argillites from 21 locations were subjected to preliminary bench- scale tests for bloating properties , and several samples were tested for ceramic properties . Samples showing favorable bloating properties were further tested in a pilot - plant - scale rotary kiln . Physical characteristics and concrete -making properties of the bloated products were determined . The Decorah shale from one area made a suitable material for a lightweight aggregate ; however , the limestone layers in the formation must be eliminated or the resulting activated lime must be controlled by quenching .

Jan 1, 1963

By H. Herbert Hughes

Iceland spar is a variety of calcite ( calcium carbonate ) characterized by its purity , transparency , and perfection of crystalline structure . It takes its name from the country in which it was discovered . The actual demand for it is small , but the supplies of high - grade optical spar are so meager that the search for it has become international in its scope . Iceland spar is a scientific necessity , for without it research precision and technology would be hampered considerably . The earliest students of mineralogy were familiar with calcite , but the transparent variety was not discovered until early in the seventeenth century , when crystals of it were found in the bed of a stream in Iceland . It received little attention until 1669 , when Erasmus Bartholinus first recognized its powers of double refraction . The results of his investigation were published in a book , " Experimenta Crystalli Islandici , " which appeared in 1670. The law governing the action of the rerracted rays was discovered by Christian Huygens eight years later . The polarization of light rays in passing through Iceland spar was discovered in 1809 by Etienne Louis Malus , a French physicist , who published a paper describing the phenomenon . His work was closely followed by that of William Nicol , who in 1828 designed the Nicol prism which is still used as the source of polarized light in most optical instruments .

Jul 1, 1931

By R. N. Love, L. Goldman

"INTRODUCTION When tannin is present in a boiler water, it causes certain difficulties in many analytical testing procedures because of its colloidal action in interfering with the removal of suspended matter by filtration and also because of the color it imparts to the boiler water.For example, in any test for phosphate in boiler water the first step is to filter out of the sample all sludge and suspended solids. Calcium phosphate in the sludge would give high results if not completely removed. If tannin is present in the sample, the sludge and suspended matter tend to pass through the filter paper so that it is difficult to remove it all. It may even be that tannin makes some of the suspended material in the sample completely nonfilterable. If this is true, it would be necessary to destroy or remove the tannin from the sample before filtering to get complete removal of calcium phosphate from the sample. In addition, if the test used is a colorimetric one, the tannin causes interference by its own color.As the calorimetric phosphate test is so convenient for control purposes and the use of tannin for boiler water treatment has become common, it has become necessary to develop suitable methods for employing the colorimetric phosphate test for boiler waters containing tannin. In this paper three different methods for doing this arc described and studied."

Oct 1, 1946

By W. P. Yant

[At the majority of mines where flame safety lamps are used either as working lights or as a means of detecting gas, no check it made on this condition of the various parts of the lamp and their assembly other than a visual ink inspection. Although this inspection should be made carefully in view of tae serious consequence that may follow Vie use of a faulty lama, In many instances the inspection is of a perfunctory nature. The Bureau of Mines has therefore designed a small box or gallery for testing lamps for defects and improper assembly before they are taken into the mine. The test simulates the condition when a lamp is extinguished by its introduction into an explosive mixture and the operator attempts to relight the wick while the lamp contains the explosive mixture. This test is more rigorous than merely subjecting a lighted lamp to an explosive methane-air mixture. In the latter test the products of combustion tend to blanket the propagation of flame from within the lamp to the exterior, especially if there are defects at the top of the gauzes. Moreover, when the lighted lamp is subjected to an explosive methane-air mixture the methane builds up slowly within the lamp until the lower inflammable limit is attained, whereupon a feeble explosion occurs within. If the nonlighted lamps is first filled with the methane-air mixture that gives the maximum violence and is than ignited, the dampening effect of products of combustion is obviated and the strain on defects is]

Jan 1, 1930

By M. P. Dalton

This paper which describes the milling practice at the Morning concentrator of the Federal Mining and Smelting Co., Mullan, Idaho, is one of a series being prepared by the Bureau of Mines. ACKNOWLEDGMENT The author wishes to acknowledge the assistance given by H. G. Washburn, general manager of the Federal Mining and Smelting Co., and by C. S. Price, assistant mill superintendent, in the preparation of this paper.

Jan 1, 1932

By H. R. Babitzke

To develop alloys suitable for use at elevated temperatures, columbium and tantalum were combined with tungsten, hafnium, vanadium, zirconium, and titanium, and the resulting alloys were evaluated with respect to fabricability, hardness, Electrical resistivity, strength at elevated temperatures, oxidation resistance, and bend transition. Of the 23 compositions tested, Cb-2OHf-5W-10Ti exhibited superior high-temperature properties. A recrystallized sample of this alloy was fabricable at room temperature, had a strength of 44,000 psi at 1,200° C, and had an oxidation rate of only 7.7 mg/cm2/hr at 1,000° C.

Jan 1, 1966

By John Gross

Studies in grinding efficiencies carried out at the Midvale plant of the U. S. Smelting, Refining & Mining Co. and at the Tooele plant of the International Smelting Co. Were made possible by the cooperation of these two companies with the U. S. Bureau of Mines. Mr. Alan Probert of the U. S. Smelting, Refining & Mining Co. and Mr. E. C. Peterson of the International Smelting Co., devoted their entire time to the work during the respective tests, and their services are hereby gratefully acknowledged. It is a pleasure to acknowledge also the assistance and kindness of the staffs of both companies in making it possible, at considerable trouble and expense, to sample the entire mill circuits and in furnishing the necessary supplies and special apparatus required in the work.

Jan 1, 1929

By V. E. Edlund

Laboratory batch flotation tests were conducted on copper converter slags to evaluate the relative merits of recovering copper from slow-cooled versus water-quenched slags. Three slags containing 1.6, 5.0, and 6.6 percent copper were used. More than 90 percent of the copper was recovered in a rougher concentrate leaving a 0.2- to 0.3-percent copper tailings when treating slow-cooled slag. Lower recoveries and higher copper tailings ranging from 0.5 to 0.6 percent copper were obtained from quenched slag. Grindability studies were made on the respective heat-treated slags. Quenched slags proved more difficult to grind than slow-cooled slags. Cost studies showed that quenched slags can be treated at slightly lower cost than slow-cooled slags. However, the cost advantage of processing quenched slags is more than offset by the higher copper recoveries obtained from slow-cooled slags.

Jan 1, 1971

By J. M. Stuve

Standard heats of formation (AH°p) of YbCl3 (c) and TmCl3 (c) were measured by solution calorimetry. Heat of solution data are given for ytterbium and thulium metals and corresponding anhydrous trichlorides in 4.360 molal hydrochloric acid. The derived standard heats of formation of YbCl3 (c) and TmCl3 (c) were -229,370 ±720 and -235,820 ±400 cal/mole, respectively, at 298.15° K. The resulting heats of formation for YbC13 and TmCl3 are about 1 kcal and 6.3 kcal more negative than previously published values.

Jan 1, 1967

By F. E. Block

The reaction between calcined dolomite and ferrosilicon has been studies with the aim of developing a continuous process for magnesium production. Small-scale tests were made in vacuum retorts similar to those used in the vacuum retort process as developed by Pidgeon (1)2/ and operated during the period of World War II in several Government-owned plants. Factors investigated with respect to the silicon efficiency were the reaction temperature, reaction time, amount of excess dolomite in the charge, and effect of adding sodium silicate to the charge to serve as a binder. Additional laboratory tests were made to study the reaction at elevated temperature but at atmospheric pressure. Silicon efficiencies exceeding 80 percent were found to result when operating in the temperature range from 1,750° to 1,800° C. for periods of 20 to 30 minutes.

Jan 1, 1956

By J. A. Organiscak

The U.S. Bureau of Mines investigated the relationship of bituminous coal seam parameters and the amount of airborne respirable dust generated at longwalls. Dust and coal samples were obtained from 20 longwalls operating in geographically representative coalfields throughout the United States. Statistical analyses of coal seam parameters and airborne respirable dust measurements indicate a likely causal relationship between seam type and respirable dust. Low-ash, high-volatile coal seams were associated with higher airborne respirable dust levels. A negative linear correlation (significant at the 95-pct confidence level) was observed between the seam's ash content and airborne respirable dust, explaining up to 18 pct (R2 = 0.18) of headgate dust level variation and up to 15 pct of tailgate dust level variation. Volatile matter was found to have a positive linear correlation with tailgate dust level, explaining 16 pct of the variation. Further data examination indicates that these relationships with dust are most likely nonlinear, because of improved R2 values over the linear correlations. However, a notable portion of longwall dust production is influenced by other operational parameters, so additional research under more controlled conditions is needed to determine the seam's causative functions.

Jan 1, 2010

By R. J. Hundhausen

The Takilma-Waldo copper district in Josephine County, Oreg., was studied by the Bureau of Mines from September 1950 to April 1.951 and from December 1953 to April 1954. Funds for the investigation were provided by the Bureau of Mines and the California-Oregon Power Co., Medford, Oreg., on a cooperative basis. The copper mines in the district are credited with a total production of ore worth $1,700,000. Since 1933 the mines have been unproductive and, except for minor exploration, largely inactive. The history of the district indicates that the copper deposits were mined principally during periods of high metal prices.

Jan 1, 1956

By F. D. DeVaney

In the course of the investigation by the U. S. Bureau of Mines and the Missouri School of Mines and Metallurgy at the Mississippi Valley Experiment Station at Rolla, Mo., on the beneficiation of the low-grade manganese ores of the country, some samples from the Cuyuna District, Linn., have been examined. The work was done under the direction of W. H. Coghill, supervising engineer of the Mississippi Valley Experiment Station. Joseph and Kinney in writing about the relative importance of Minnesota deposits of low-grade ore compared to the total reserves say: "***It has been estimated that 26 to 35 million tons of ore contain 5 to 35 per cent of manganese, and the total domestic tonnage is from 75 to 48 million tons. The mean of these values is 30.5 million and 42 million tons, so it is seen that about 75 per cent of the reserves are in Minnesota." The manganese-bearing ores of the Cuyuna district maybe roughly grouped into two classes. The most abundant ore is of the low-silica, low-manganese, and high-phosphorus type called brown are. The other type is the so-called black ore, which is characterized by a higher manganese and silica content and by a lowe phosphorus analysis than the brown ore. As a general rule the brown ore carries less than 10 per cent of manganese while the black ore contains about 15 per cent and sometimes as high as 22 per cent of manganese.

Jan 1, 1930

By Christopher Mark, Anthony T. Iannacchione

Falls of ground continue to be one of the most serious causes of injury to U.S. miners. Of the 256 fatal injuries that occurred in mining between 1996 and 1998, 52 (20%) were caused by falls of ground (Table I). Falls of ground affect some sectors of the mining industry more severely than others. For instance, nearly 40% of the 98 coal mine fatalities between 1996 and 1998 were caused by falls of ground. Underground miners are at much greater risk than surface miners. Nearly half (45 out of 101) of underground mine fatalities were attributed to roof, rib and face falls, while less than 5% of the 155 surface fatalities were caused by falls of highwalls or slopes. Sources of Data All of the injury data examined in this study were derived from MSHA’s Fatal Investigation Reports (www.msha.gov)and the MSHA accident database. Because falls of ground often result in serious injury, MSHA Fatal Alert Bulletins and Fatal Investigation Reports provide a useful snapshot of ground control issues in the mining industry. MSHA requires that mines file a report on every reportable accident that occurs, containing information on the accident’s location, severity, classification, activity, and nature of injury, etc. A short narrative is generally included as well. Accident reports can be searched by many of the above fields. From 1996 to 1998, miners suffered a total of 55,096 injuries, which ranged in severity from death (degree 1) to injuries with no days away from work nor restricted duty (degree 6). Six percent of the total injuries were from falls of ground, including machine accidents where caving rock was coded as the source. As the data in Table II indicate, 98% of all non-fatal fall of ground injuries occurred in underground mines, with underground coal mines accounting for 83% of the total. Table II also shows the distribution non-fatal fall of ground injuries by severity and commodity. The injuries are classified into Lost Time Injuries that resulted in permanent disability (degree 2) or days off work (degrees 3-4), and Injuries Without Lost Time that resulted in no more than restricted duty (degree 5-6). Overall, groundfall injuries appear to be more serious than other types of mining injuries. 65% of all ground fall injuries resulted in lost time compared to 54% of all types of mining injuries.

By George E. Blandford

A deterministic model to assess the hydrologic impact of small watersheds subjected to unsteady storm events is presented. The overland flow model is based on the kinematic wave approximation coupled with a Green-Ampt infiltration equation. The Green-Ampt infiltration parameters are estimated using the USDA-ARS parameter estimation technique which is based on soil moisture-tension data. A Galerkin finite element formulation of the kinematic wave approximation is presented for the deterministic analysis of overland flow on small watersheds. The finite element formulation includes linear, quadratic and cubic Lagrangian one-dimensional spatial elements. A linear time variation is assumed which includes both explicit and implicit time marching algorithms, depending on the choice of the time weighting parameter. The implicit time algorithms result in a system of nonlinear equations which are evaluated using a modified Newton-Raphson iteration scheme. Initial solution estimates are generated using a linear finite difference procedure. The coupled infiltration overland flow model is tested using storm data for impervious surfaces, a laboratory soil flume, and two natural, USDA-ARS experimental watersheds.

Jan 1, 1983

By K. K. Kershner, J. G. Donaldson

This investigation was conducted to obtain data on optimum conditions for chloridizing metal sulfides . Salt- roasting galena at 450° C for 8 hours chloridized 75 percent of the lead ; in an equal time of treatment at 750° C , the process chloridized 42 percent of the zinc in sphalerite . Hydrogen chloride at 500° C completely chloridized galena in 15 minutes , and at 600° C converted all of the zinc in sphalerite to the chloride in 4 hours .

Jan 1, 1963