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By Charles A. R. Lambly

This paper, which describes the mining practices of the Pend Oreille Mines & Metals Co. at Metaline Falls, Wash., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in various mining districts of the United States. ACKNOWLEDGMENTS Acknowledgment is made to L. P. Larson, president, and Jens Jensen, secretary, of the Pend Oreille Mines & Metals Co. for permission to publish this paper. information was supplied by E. Berglund, mine superintendent; Earl Miller, chief engineer; Lynn Kinney, John Currie, and Wally Frick, engineers; Arthur Newman, chief clerk; and Jack Crampton, assayer.

Jan 1, 1941

By Albert W. Deurbrouck

This report describes the preparation characteristics of the significant, presently producing coalbeds in Mercer County, W. Va. Approximately 650,000 tons of coal was produced in Mercer County, W. Va., in 1960, of which over 630,000 tons was cleaned in four preparation plants. In 1960 the Pocahontas Nos. 3, 6, and 11 coalbeds supplied 99.5 percent of the total coal mined in the county. Because the number of working mines In this county was small, only six samples were collected; four of which were of metallurgical quality as mined. The remaining two samples could be upgraded by washing at suitable specific gravities. Many of the samples taken were of metallurgical quality as mined; however, the float-and-sink analysis on these coals has been included to point out their amenability to the production of premium quality, special purpose coals. In general the coals were low-volatile bituminous in rank with low ash and sulfur contents.

Jan 1, 1963

By T. L. Joseph

The size and accessibility of the Minnesota manganiferous iron ore deposits make them attractive as a potential source of erromanganese, which is essential in the production of steel. For several years the Bureau of Mines has been conducting experiments to determine the feasibility of producing ferromanganese from these ores by a three-step process which involves (1) the smelting of the ores in the blast furnaoe to produce a high-phosphorus spiegel; (2) the treatment of the spiegel produced from step 1 in an electric or open-hearth furnace to separate the manganese from the phosphorus and the iron; and 3) the smelting of the high-manganese slag from step 2 to produce forromanganese. The details of the first two steps of the process and the results of tests with the experimental furnaces Lave been given in previous reports.5 The m$ or part of the experimental work on the second step has been conducted in a half-ton open-hearth furnace. Some preliminary tests showed, however, that the electric furnace has some distinct advantages over the open hearth for producing, from high-phosphorus spiegel, a slag containing from 45 to 55 per cent manganese and phosphorus and iron in amounts required for ferro-grade ore. The electric furnace tests described in this paper were made to get more information as to the possibilities of the electric furnace in connection with this problem and to study the fluxing effect of alumina on high-manganese slags. Herty, Conley, and Royer have reported' results of laboratory tests which showed that slags containing from 60 to 75 per cent MnO, from 8 to 10 per cent S102, and small amounts of CaO MgO, and FeO, were sufficiently fluid at 1,450° to 1,550° C. to pour readily if 12 to 14 per cent alumina was present. With a normal A1203 content resulting from the A1203 in the

Jan 1, 1931

By James J. Olson

Previous Bureau of Mines studies of vibrations from quarry blasts have shown that the square root of the charge-weight may be used to group particle velocity data from various charge sizes, and that empirical propagation equations may be used to estimate vibration amplitudes. Particle accelerations of the sandstone roof of the White Pine Copper mine, Michigan, were measured to determine whether similar propagation equations may be developed for underground mine blasts. Vibration data from White Pine blasts were best grouped by scaling with the square root of the charge weight. Cube root scaling did not effectively group the data. The empirical propagation equation AW1/2 = 50,000 (R/W1/2)-2.21 where A is peak-to-peak acceleration in g's, W is the zero-delay charge-weight in pounds, and R is the distance from the blast in feet, may be used to estimate maximum vibration amplitudes from production sized blasts. Vibration differences among headings and types of explosive charge (AN-FO and dynamite), while statistically significant, were not a major factor in the estimation of maximum vibration amplitudes with an empirical propagation equation. Vibration differences between types of explosive charge were larger than the differences among headings, indicating that some reduction of vibration amplitude might be gained by using AN-FO rather than dynamite. Acceleration records from both White Pine's AN-FO and dynamite production blasts show that high intensity vibrations from the delayed portions of the blast (each delay interval = 25 milliseconds) were separate events, and that the zero-delay portion of the blast produced the maximum vibration amplitudes. If the pull of the underground blast round can be maintained, a reduction of the zero-delay charge-weight may effectively reduce the maximum vibration amplitude of the blast.

Jan 1, 1970

By K. R. Dorman

To further investigate the potential of precast concrete sets as a support medium for underground mines, the Bureau of Mines designed a five-piece precast concrete drift set for a small opening and tested it to destruction in a straining frame. Twenty-seven tests were made with three sizes of members using three loading conditions. In addition, six tests were made with sets in a distorted configuration, Test results and typical failure patterns are presented. A comparison of results with those previously reported for the three-piece set shows the five-piece set supports considerably larger total loads than does the three-piece set of equivalent cross section designed for the same size of opening. Recommendations are made for improvements in design.

Jan 1, 1969

By B. J. Arnold, F. F. Aplan

"The captive bubble and sessile drop contact angle techniques have been used to evaluate the hydrophobicity of petrographically identified coal macerals. The magnitude of the contact angle on vitrinite is shown to be a function of coal rank ( %C, %0 and % vitrinite reflectance), increasing with increasing rank to a maximum for low volatile bituminous rank coals then decreasing for anthracite. The least data scatter is found when vitrinite reflectance is used as a rank parameter. Contact angles measured or estimated for other discrete macerals, indicate a variation in hydrophobicity based on coal type. These data correlate well with known flotation results. Coal is a heterogeneous mixture of plant remains and associated minerals that have undergone chemical and physical changes by biological and geological processes. These plant remains form coal macerals, discrete organic entities in the coal which have characteristic chemical and physical properties. As the differing chemical nature of each maceral will affect its behaviour in processes such as carbonization the separation of macerals during coal preparation may provide an important asset in coal utilization.Separation of some of the macerals based on specific gravity has been achieved in the laboratory, and by Sun and Cohen , in a study of two Pennsylvania bituminous coal preparation plants. It was indicated that the lighter exinites report almost exclusively to the clean coal while the denser inertinites are concentrated in the higher gravity fractions. The Longwy-Burstlein process6 took advantage of the difference in hardness or friability of the macerals by using impact breakage followed by screening to remove the more friable vitrain,clarain and fusain. The remaining durain, often high in spore content, was then recrushed. The re-mixed fractions produced the optimum size for obtaining the best coke strength for a particular coal.Separation or concentration of rnacerals by froth flotation largely depends on differences in the hydrophobicity of the macerals. Sun and Cohen 5 . indicated an order of decreasing floatability as exinite, vitrinite and inertinite, while a Russian study (as cited by Brown 7 ) showed that vitrains floated more readily than the duller types. More recently, Hirt and Aplan8 showed that 'pseudovitrinite' floats somewhat faster than does vitrinite while fusinite floats very slowly. Olson and A plan found that vitrinite floated easily while substantial quantities of the non-floated coal contained fusinitic material. Burdon noted that vitrinite is more floatable than semifusinite, and Sarker et a/. 11 have shown that vitrinite is selectively concentrated by froth flotation and oil agglomeration. Sun indicated that flotation, based on his calculated floatability index, should decrease in the order clarain, vitrain, fusain and durain; while Horsley and Smith 13 indicated the decrease to be: vitrain, clarain, durain and fusain. These differences can be attributed to the specific coals used in each study and to the individual macerals composing each coal type within a given coal."

Jan 1, 1989

By Heinz W. Sternberg

A method for the electrochemical reduction of the benzene ring was developed and applied to the electrochemical reduction of coal. Successive electrochemical reductions of a vitrain from low-volatile bituminous coal in ethylenediamine saturated with lithium chloride resulted in the addition of 53 hydrogens per 100 carbon atoms. Ultimate analyses and pyridine solubility of the vitrain recovered after each reduction showed that hydrogen added at the beginning has a much greater effect on solubility than hydrogen added at a later stage. Surprisingly, the removal of sulfur from the vitrain takes place only after the more reactive aromatic rings are reduced. Nuclear magnetic resonance analysis and average molecular weight determination of the extracts of the reduced vitrain samples, representing about 18 percent of the vitrain, showed that these fractions had 95 percent of their hydrogen content on saturated carbon atoms and an average molecular weight of 800 to 900. A study of the effect of operating variables on current efficiency showed that current efficiency is highest with aluminum as cathode material and with lithium chloride as electrolyte. A substantial increase in current efficiency of difficulty reducible olefinic double bonds was achieved by adding a proton donor. This result is significant in connection with the electrochemical reduction of coal which proceeds from readily reducible aromatic double bonds to difficultly reducible isolated double bonds. It is proposed that reduction is achieved by electrolytically generated and subsequently solvated electrons and hence does not require prior adsorption of the substrate at the electrode surface. This offers a distinct advantage for electrolytic reduction of sparingly or insoluble substrates such as coal.

Jan 1, 1967

By H. F. Yancey

Although a general relationship exists between the two criteria used to measure sharpness of separation -error area and probable error -they sometimes give quite different appraisals of a particular washing operation. Error area takes into account how the entire raw coal was treated, whereas probable error reflects only how the material of intermediate density was separated, ignoring completely the recovery of clean coal and the rejection of heavy impurity. Error area is thus more reliable for general use. In heavy-medium cleaning, sharpness of separation decreases with increase in separating density, but ordinarily the change is not great enough to affect the yield and ash content of washed coal measurably. Therefore, distribution curves for heavy-medium units can be transposed from one separating density to another, at least in the range of separating densities ordinarily used in the United States.

Jan 1, 1955

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 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 Ludwig Schmidt

The attention of operators of oil-producing properties long has been directed toward methods of' disposing of petroleum wastes as well as the disposal of oil-field brines. The problem of disposing of' petroleum wastes is not easy to solve, and although many operators are to be commended for the efforts they have made, much work remains to be done before the problem can be considered solved. Petroleum wastes include emulsions of petroleum and brine or mixtures of petroleum and sand that cannot be "broken down" or treated economically by known methods of separating petroleum from deleterious matter; crude petroleum that escapes from pipe lines, fittings, and tanks because of holes in the lines, leaky connections, or some accident; and oil-saturated materials that accumulate accidentally or otherwise an the normal operation of an oil-producing property.

Jan 1, 1938

By Ludwig Schmidt

[The attention of operators of oil-producing, properties long has been directed toward methods of disposing of petroleum wastes as well as the disposal of oil-field brines. The problem of disposing of petroleum wastes is not easy to solve, and although many operators are to be commended for the effort they have made, much work remains to be done before the Problem can be considered solved. Petroleum wastes include emulsions of petroleum and brine or matures of petroleum and sand that cannot be "broken down" or treated economically by known methods of separating petroleum from deleterious natter; crude petroleum that escapes from pipe lines, fittings, and tanks because of holes in the lines, leaky connections, or some accident; and oil-saturated materials that accumulate accidentally or otherwise in the normal operation of an oil-producing property.]

Jan 1, 1938

By James Paone

The Bureau of Mines made drillability studies with impregnated diamond bits in the laboratory on 7 rock types and in the field on 21 different rock types. Results indicate that drill parameters of rotational speed, thrust, and torque must produce sufficient applied forces to induce stress levels that cause continuous failure in rock to achieve efficient penetration rates. Higher rotational speeds appear to be more effective in drilling relatively harder rocks, although the increased speed causes more bit wear; increases in thrust result in higher drilling rates but not linearly; and up to a critical value a linear relation exists between torque and penetration rate for a specific rock type. Penetration rates with impregnated bits show a trend similar to that obtained with surface-set bits for rock under 25,000 psi compressive strength.

Jan 1, 1966

By Donald H. Mullen, Walter R. Storms

"INTRODUCTION The Copper Flat area of the Central mining district, Grant County, N. Mex., has been visited by numerous engineers 4/ of the Bureau of Mines and geologists 5/ of the Federal Geological Survey. In December 1944 the Bureau. 6/ proposed that geophysical work be done in that area in order to locate favorable sites for future company exploratory and development work. This geo-physical work was begun early in 1945 but never fully completed because of insufficient funds. The engineers who made the survey recommended that more work be done, especially to locate the bottom of the Copper Flat laccolith by resistivity-depth surveys. All known minable zinc-lead ore bodies had been found above this laccolith in the Copper Flat mine, but it was thought that other minable ore deposits should occur in favorable limestones beneath it. The geophysicists also recommended core drilling beneath the laccolith.In the summer of 1946, following some mapping by S. G. Lasky of the Federal Geological Survey, funds were appropriated for a Bureau of Mines project in the Copper Flat area. The project was completed in June 1947. 8/"

Apr 1, 1948

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 John W. Buch

This is the first progress report to be released on the anthracite, mechanical mining research and engineering development program of the Bureau of Mines. This phase of Bureau work, which was initiated as an aid to stimulating wartime production of anthracite, has been continued after the war to assist primarily in improving the general economic position of the anthracite industry. Field work was started in. the 1945 fiscal year with the cooperation of an advisory committee representing management, labor, and the Commonwealth of Pennsylvania. For a beginning, several matters were suggested by members of this advisory committee as being worthy of investigation, and sections of underground mines yore offered for test purposes. Among the suggestions accepted for investigation was the problem of increasing the rate of advance for driving gangways in thin, steeply pitching anthracite beds 4 to 6 feet thick and pitching 60 degrees or more. The problem was undertaken as a field study, and this report relates to accomplishments on this project to June 30, 1947.

Jan 1, 1949

By C. H. Elder

A 5-hole pattern was drilled from the surface at a site near Oak Grove, Jefferson County, Ala., to degasify the gassy Mary Lee coal bed in advance of mining. Gas and water production was monitored for 1 year, 4 months to allow gas flow to stabilize fully. A thickened water stimulation treatment was designed and applied in one hole of the pattern to evaluate this degasification technique for the Mary Lee coalbed. A gas production rate of 70,000 fts/day after stimulation treatment indicates that the use of vertical boreholes coupled with hydraulic fracturing in advance of mining the Mary Lee coalbed would provide for more rapid degasification and could provide a possible source of natural gas.

Jan 1, 1974

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 A. C. Richardson

During the past two and a half years the U. S. Bureau of Mines and the University of Alabama, with the cooperation of the different coal operators, have been making an extensive study of coal preparation in the State of Alabama. Considerable time has been devoted to the study of the washing characteristics of the Mary Lee bed and the various methods used in preparing from it a low-ash coal suitable for the manufacture of metallurgical coke. One of the phases of this problem is the utilization of middlings products from the washing plants. This paper gives the results of treating jig middlings on a coal-washing table at the Bureau of Mines laboratory at Tuscaloosa, Ala. The sample used was secured from the Sayreton washery Of the Republic Steel Corporation, Sayreton, Ala.

Jan 1, 1931

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