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By A. C. Richardson

The mine of the Porter Coal Co. is located at the town of Porter in the northwestern part of Jefferson County, Ala., about 20 miles west of Birmingham. The operations in this mine are confined to the middle and bottom benches of the Mary Lee bed. The coal from the Porter mine is handpicked and washed before being placed on the market. The handpicked lump coal and the washed egg and nut coal are sold chiefly as domestic and steam-raising fuel. The coal finer than 1 inch is washed in 2-compartment jigs and utilized in the manufacture of metallurgical coke. The coal company has found that, when coal ranging in size from 1 to 0 inch is washed in jigs, a considerable amount of high-ash material finer than 3/16 inch remains in the washed coal. This paper gives the results of an investigation which was conducted for the purpose of determining the washing characteristics of the through 3/16-inch raw coal and the extent to which the ash might be reduced by means of coal-washing tables. This investigation has been made in connection with an extensive study of the coal-washing problems now being conducted by the United States Bureau of Mines and the University of Alabama, with the cooperation of the coal-mining companies of the State.

Jan 1, 1933

By K. O. Bennington

Thermodynamic properties were determined by the Federal Bureau of Mines for lithium metasilicate (Li2Si03) and lithium disilicate (Li2Si205). Their enthalpies of formation were investigated by hydrofluoric acid solution calorimetry. The standard values are ?Hf°298 -393.8 ± 0.8 kcal/mole for Li2Si03, and ?Hf°298 -611.8 ± 1.0 kcal/mole for LiSi205. Enthalpy increments above 298 K were measured by copper-block drop calorimetry from 298 to 1,404 K for Li2Si03, and from 298 to 1,281 K for Li2Si205. Low-temperature heat capacities were determined adiabatically from 6 to 305 K for Li2Si205 only. The derived standard entropy is S°298 = 29.20 ± 0.10 cal/deg-mole. The various experimental data were combined with other data from the literature, and resulting properties of ?Hf°, ?Gf°, and log Kf were tabulated as a function of temperature.

Jan 1, 1976

A study was conducted by the Bureau of Mines to evaluate natural gas as an automotive fuel and to provide guidelines for optimum engine adjustments for low exhaust emissions. The study was conducted using a single-cylinder engine, a multicylinder engine, and a total of eight vehicles. Results from single-cylinder engine tests showed that the light-load, lean-limit misfire region for natural gas begins at an air-fuel ratio between 150 and 160 pct of stoichiometric. Changes in ignition timing significantly influenced emissions of nitrogen oxides and hydrocarbons, but had little effect on carbon monoxide emission. Low emissions can be achieved with current-design engines by adjustment of engine parameters, but only with heavy penalty to engine performance. Emissions from vehicles fueled with natural gas are virtually unaffected by ambient temperature change within the range 20° to 100° F. The organic emissions from engines fueled with natural gas were estimated to be 22 to 25 pct as reactive as the emissions produced using gasoline. Levels of exhaust emissions from vehicles fueled with natural gas were unchanged over 10,000 miles of normal driving.

Jan 1, 1973

By J. A. Eisele, D. J. Bauer, D. E. Shanks

As part of its effort to produce cell - grade alumina from clay , the Bureau of Mines investigated the hydrogen chloride gas - sparging crystallization of aluminum chloride hexahydrate ( ACH ) from aluminum chloride liquor , to provide information for optimizing the crystallization operation . Four parameters important in controlling the crystallization of the aluminum chloride hexahydrate and the concentration of impurities , particularly phosphorus and magnesium , in ACH crystals are ( 1 ) aluminum chloride concentration in the feed solution to crystallization , ( 2 ) hydrogen chloride gas flow rate , ( 3 ) temperature , and ( 4 ) concentration of phosphorus and magnesium also in the feed solution . Parameters 1 , 2 , and 3 affect crystal formation . The combined effects are very important because the phosphorus and magnesium concentrate in the crystals during the early stages of crystal growth . Aluminum chloride hexahydrate of cell -grade purity was crystallized from saturated aluminum chloride solutions containing less than 0.003 wt - pct P205 and 0.010 wt - pct Mg0 . Crystallization temperatures less than 60° C decreased crystal purity .

Jan 1, 1965

By John Ward Smith

The Bureau of Mines drilled Wyoming Corehole No. 1 in Sweetwater County, Wyo., to sample Green River Formation oil shale. Core obtained was assayed for oil yield to determine richness and stratigraphic distribution of oil shale in the deposit. Oil shale in place at Wyoming No. 1 site represents over 200 million barrels of oil per square mile. Additional data useful in evaluating the deposit, including generalized stratigraphy and mineralogy, detailed lithologic descriptions of the core, rock specific gravity, and bore-hole logs, are presented with the oil-yield data. The sampled Wyoming oil shale resembles Mahogany-zone oil shale in rock properties and gross mineralogy. A statistically derived equation relating shale density to oil yield for the Wyoming deposit compares with a similar relationship valid for the better known Mahogany-zone oil shales in Colorado and Utah. A density log from Wyoming Corehole No. 1 is calibrated for direct oil-yield logging. The alternating rich and lean beds of shale at this site may permit creating the permeability necessary for direct production of shale oil from the shale in place.

Jan 1, 1968

Low-cost housing, like automobiles, should be appraised in the light not merely of first cost but of upkeep as well. Even more important than the number of miles the family car will go on a gallon of gasoline is the number of days the family home can be kept comfortable on a ton of fuel. A furnace tender who tossed every third shovelful of coal into the ashcan would lose his job promptly, but the effect is the same when homes continue year after year to pour out precious heat through uninsulated roofs and walls, Greater economy in household heating means even more to the national economy than to the individual, especially now that we are preparing for defense. Our fuel resources, although large, should be conserved. If less fuel is used for civilian needs, augmented requirements for defense can be met without unduly increasing the number of men needed at the coal mines and oil ells or adding new producing units that might complicate ultimate readjustment to peacetime conditions when the emergency is past and over-expansion of many industries brings new problems if unnecessary demands for transportation facilities are reduced, public carriers will be able to haul more munitions, and manpower needed for national defense will be released; and by protecting workers from health hazards in their homes additional man-hours of productive effort will be gained. Moreover, reducing the running expenses of houses by proper heat insulation helps home owners to maintain payments on property, and by minimizing foreclosures helps to stabilize the financial structure of the country. In short, here is a situation where the interests of the individual and the Nation are identical and the greatest good for the greatest number is obtained without sacrifice to anyone.

Jan 1, 1941

This volume contains a series of papers describing research conducted by the Bureau of Mines to develop or improve equipment and systems that satisfy the communication requirements of miners doing work related to rail, belt-conveyor, trackless, and hoist haulage systems.

Jan 1, 1977

By T. Estelle Gardner

Heat-capacity measurements were made over the range 8° to 350° K on beryllium sulfate dihydrate and beryllium sulfate tetrahydrate using an adiabatic calorimeter. No anomalies were noted in the curve for either compound. Smooth values of heat capacity, entropy, enthalpy function, and free-energy function were calculated from the heat-capacity data at 10° K intervals and at 273.15° and 298.15° K. The entropy values calculated at 298.15° K were 39.01 ± 0.12 entropy units (eu) for the dihydrate and 55.68 ± 0.17 eu for the tetrahydrate.

Jan 1, 1967

By T. J. Ballard

Chromite deposits in the vicinity of Louise, Troup County, Ga., were studied y the Bureau of Mines from September 1, 1942, to March, 15, 1943. They are about three-fourths of a mile southeast of Louise and 8 miles northeast of La Grange, Troup County, Ga. The existence of chromite deposits in that area has been known for more than 75 years, but no active prospecting was done until World War I. Prospecting continued intermittently' until 1928. The Bureau became interested in the deposits in connection with its strategic minerals investigations during World War II. The chromite in these deposits occurs as grains ranging from "pin-head" size to 3/8-inch and occasionally 1 inch. Some of the material is magnetic, indicating the presence of magnetite. Of the 300 samples taken during the course of the project, 266 were analyzed. Tables showing the analyses accompany this report.

Jan 1, 1948

By Homer J. Ballinger

The Alma, Degraff and other mines controlled by the Mon-Ark Mining Co. comprise one of the more important groups of zinc-lead mines in Christian County, Mo. The mines were first operated in .1857 and produced more than 5 million pounds of lead from rich, shallow ore deposits. Recent exploration and development led to the discovery of zinc sulfide ore at a depth of 165 to 214 feet in the northern part of the Alma mine. After examination of these mines in September 1942 by Bureau of Mines engineers, investigation of the extension -of the Alma mine and of the depth of mineralization at the other mines appeared justified in order to encourage the production of additional zinc and lead for war purposes. Twenty-nine churn-drill holes totaling 6.463 feet of bore were completed by the. Bureau from September 1943 to January 1944.

Jan 1, 1948

By Nan C. Jensen, Oliver Bowles

"INTRODUCTION Limestone (which consists essentially of calcium carbonate) and dolomite (calcium magnesium carbonate) occur widely in the United States. Their presence is of vast economic importance, because they are used much more extensively than any other form of rock. In 1945, limestone (which, broadly, includes dolomite) was quarried in every State except Delaware, New Hampshire, North Dakota, and Rhode Island, and also in Hawaii and Puerto Rico. Total production (including that used in cement and lime manufacture) exceeded 151,700,000 tons, or 79 percent of the quantity of all kinds of stone sold or used during that year.Important well-known uses of limestone are as concrete aggregate, road material, railroad ballast, for liming the land, for cement manufacture, as riprap for shore protection, harbor work, and spillways at dams, and as building stone.. None of these uses, however, are considered herein. The purpose of this paper is to discuss the industrial and chemical uses that are less widely known and yet are of tremendous importance in a great variety of processing industries. Important examples are dolomite as a refractory furnace lining and limestone as a fluxing agent in blast furnaces, and as a raw material employed in sugar, paper, glass, and alkali manufacture.PRIOR REPORTIn May 1941, the Bureau issued a report 4/ that described these uses in some detail. As new and important developments have taken place during the ensuing years, a revision and representation of the salient features of these uses seem desirable. Asphalt filler and mineral wool uses included in the earlier report are omitted from this paper because they are identified more closely with the highway and building industries, respectively, than with the industrial applications."

May 1, 1947

By C. W. Vierrether

Tailings from the Pea Ridge iron mine contain significant amounts of apatite, which has rare-earth element values associated with it. In association with the recovery of rare-earth minerals as a secondary resource, the U.S. Bureau of Mines conducted an investigation on the recover ability of the rare-earth minerals from these tailings. The mill tailings were subjected to a phosphate flotation to separate the apatite from other constituents. More than 70-pct recovery of the rare-earth values was achieved. Based on mineralogical characterization and prior analysis of rare-earth-bearing breccia pipe material at Pea Ridge, it is proposed that processing this phosphate concentrate on a vanner table would yield up to a 95-pct recovery of the rare earths in the concentrate, with the apatite reporting to the tailings. Intensive ore microscopy studies of the original tailings to the flotation products led to the identification of monazite, xenotime, and rare-earth-enriched apatite as the major rare-earth-bearing minerals in the tailings.

Jan 1, 2010

By Walter E. Lewis

Ventilation-air-heating plants are in use at several iron mines on the Menominee Iron Range, Iron River, Mich. Many of the mines are exceptionally wet; during winter months, when fresh air is forced down the wet air shafts into the mine, it is usually necessary to heat the fresh air to above freezing so that the openings will not be closed by ice. The problem of ice closing air shafts has been solved by the practice of reversing the air current before the openings have become completely closed. This procedure involves drawing warm air from the mine up the usual down-draft air shaft. The M. A. Hanna Co. has found, at some of their mines on the Menominee Range, that it is more convenient to heat the below-freezing air rather than reverse the air current. Intermittent freezing and thawing of ice that has formed in the air shaft tends to loosen the wall rock, requiring major shaft repairs. The openings are kept free of ice the year around by heating the fresh air during periods of below-freezing weather. Table 1 shows the monthly minimum moan, maximum mean, and mean temperatures for the Iron River area. Under normal conditions of temperature, the furnaces are fired in November and usually are not allowed to go out until April of the following year.

Jan 1, 1951

By Thomas J. Albin

This U.S. Bureau of Mines report identifies potential causes of slip-and-fall accidents occurring during surface mine equipment maintenance and describes the relative roles of direct worker behavior and machine design. The relative roles of human behavior and machine design in the causation of slip-and-fall accidents were determined through analysis of accident records, observations of maintenance worker behavior, and evaluation of mine machinery. From these data, relative risk ratios were calculated. Behavior had a relative risk ratio of 1.5; machine design, specifically access systems design, had a relative risk ratio of 2.2. Of the access systems, ladders had the highest relative risk ratio, 7.0. This study suggests that accident intervention would be most profitably made in improving the design of systems used to access maintenance worker areas of mining equipment.

Jan 1, 1990

By William Cochran

Data on the cost and quantity available were developed for rutile (TiO2), which is potentially recoverable as a byproduct at sand-washing plants in the Southeastern States of Alabama, Georgia, North Carolina, and South Carolina. Baaed on 1969 production data, an estimated 4,300 tons of rutile could be recovered annually from plants that process more than 25,000 tons of sand per year. Rutile prices at which this resource would be available ranged upward from $262 per ton, compared with the current market value of $185 per ton.

Jan 1, 1972

By T. D. Hackett

Multislice mining methods were analyzed by the U.S. Bureau of Mines to determine their application to western United States thick coal seams; ground control, geology, and costs were considered. Multislice mining is used in widely varying seam conditions worldwide, including flat seams too thick to mine in a single pass, pitching thick seams, and seams containing a rock parting. Longwall multislice methods predominate, but room-and-pillar variants also exist. The initial use of the method in western seams is planned at a deep Colorado mine where a rock parting will be used to separate two slices mined by longwall. Ground control and spontaneous combustion are major hazards associated with multislice mining. A well-consolidated upper slice gob can reduce ground control problems and provide a seal against spontaneous combustion. Geologic analysis indicates that the consolidation of the gob depends on the composition of the upper slice roof, the presence of water, and sufficient overburden pressure. A geologically competent intermediate rock parting can also reduce ground control problems and seal against spontaneous combustion. To compete in western coal markets, the cost of multislice mining must be within the range of normal longwall costs. Analysis indicates that multislice operating costs should be within this range, and that multislice mining costs decrease as panel width increases. Relatively wide (600 to 800 ft) panels also provide increased coal recovery.

Jan 1, 1990

By Scott W. Hazen, George W. Gladfelter

This report presents the results of an initial investigation into some problems resulting from the use of assays representing unequal sample interval lengths and the use of the weighted average grade of ore in evaluating bedded mineral deposits . A mathematical proof and examples are given to show that the unweighted and weighted assay averages are equivalent when there is no correlation between assay value and sample interval length but that these averages are different when there is correlation between assay value and sample interval length . The amount of this difference between estimates is a function of the degree of correlation . One set of sample and assay data , based on 11 stratigraphic sections of the Phosphoria formation in Idaho , indicates that the relationship between the amount of difference between estimates and the correlation factor is approximately linear . If this correlation relationship can be established , within acceptable limits of precision , as a consistent attribute of deposits , the estimate of weighted average grade of ore could be predicted directly from the unweighted estimate of grade of ore by using the relationship as a prediction factor . Randomness tests on the sample and assay data from the Phosphoria formation , using the mean - square - successive - difference method , indicate that correlation between assay value and sample interval length ( each sample interval length represents an individual bed or stratum of the formation ) , apparently has little effect on the independence between successive assays , between successive sample interval lengths , and between the products of assays and sample interval lengths . Therefore , these data can be analyzed statistically as long as the original sample sections have been selected at random for sampling .

Jan 1, 1964

By G. W. Jones

[As a part of its investigations pertaining to the promotion of safety, the Bureau of Mines is investigating various means, useful for the elimination or mitigation of the explosion hazards of combustible gases encountered in mining and industry. Information has been obtained and a procedure developed whereby the explosibility of many complex, gaseous, combustible atmosphere may be calculated in a simple manner without the necessity of performing laborious laboratory experiment. In a previous publication4/ data were given and a method described whereby the limits of inflammability of gaseous mixtures, including methane, hydrogen, carbon monoxide, nitrogen, carbon dioxide, and oxygen, could be determined by calculation. The information published in that retort enables one to calculate the limits of inflammability of such gases are liberated by mine fires, gases from explosives, automobile exhaust gas, gases present after mine explosions, blast-furnace gas, and other gases containing part of or all of the above-listed constituents.]

Jan 1, 1938

By Glen C. Ware

The Bureau of Mines determined the factors involved in the corrosion of starting sheets used in the production of electrolytic zinc with the ultimate purpose of adapting zinc starting sheets to commercial practice . Under present practice , zinc is electrodeposited on aluminum cathodes and subsequently stripped for melting . The use of zinc instead of aluminum would eliminate the need to strip the deposit , thereby reducing the cost of handling and melting it , but zinc has not been suitable because it was too vulnerable to the corrosive attack of the electrolyte . Serious attack was found to be limited to the areas of the cathodes situated immediately above the surface of the electrolyte and to re - entrant corners . It was possible to avoid solution - level corrosion by immersing the starting sheets completely , exposing only a relatively heavy suspension member to solution - level attack . Zinc starting sheets could be made as reliable as aluminum and could be continued in residence for periods up to 39 days . Periods as long as a week were feasible under conditions similar to those found in commercial practice . A test of zirconium as a starting - sheet material showed that it promoted corrosion of the deposit to a lesser extent than aluminum and that the deposit adhered less tenaciously . These two properties lend themselves to the development of ways to strip deposits mechanically from zirconium starting sheets . Titanium was unsuitable for use as a starting - sheet material .

Jan 1, 1963

By W. D. Mcmillan

During the fall of 1943 the Bureau of Mines put down four churn-drill holes totaling 435 feet of bore at the McGregor zinc lead mine near Potosi, Washington County, Mo., after the property had been examined by John Soule, an engineer of the Bureau, in the fall of 1942. A small production of lead and barite ore had been maintained at this property for many Years from shallow deposits in residual clays. A few shafts had penetrated the underlying dolomites and exposed a network of narrow fractures containing galena, sphalerite, barite, and marcasite. The drilling by the Bureau tested conditions at depths ranging from 80 to 130 feet. This report sets forth the data resulting from the work.

Jan 1, 1948