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By W. W. Adams

"The present world-wide demand for increased production in all branches of essential industry involves a matter of vital concern t persons engaged in the mining industry, namely, the productive capacity of the individual mine employee. This applies particularly to coal-mining, upon which other industries so largely depend.The folded and faulted condition of the coal beds in some countries, as well as the thinness and depth of the seams, the adaptability to the beds of available mining machines and equipment are factors which cannot be overlooked in determining what increase in individual output may be looked for in any given country. This subject, while of fundamental importance, can only be referred to in a paper of this length, the primary object here being merely to present a comparative tatamant of individual output under prevailing conditions.The quantity of coal produced by a miner does not accurately indicate the miner's capacity as a workman, not only because of the natural conditions referred to above that limit his annual output, but also because of human factors which may possibly, however, be controlled, such as the demand for coal, the car supply, use of labor-saving machinery, number of days worked during the year, accidents in the mine, etc. It will, however, be an aid in answering the important question as to how and where the immediate need for coal throughout the world may best be surlier, if we examine the output of the miners in the important coal-producing countries over a period of years.Complete official information for recent years is, for several countries, jacking, particularly for France, Austria, and Prussia, but partial data from unofficial sources may be used to show the individual output of the miners in these countries."

Jul 1, 1920

By Laurance L. Oden

Titanium-enriched smelter slag produced commercially by Quebec Iron and Titanium Corp., Sorel, Quebec, was evaluated as feed material for a process developed by the Bureau of Mines to prepare rutile. Glass-forming agents including P205, B203, and two binary mixtures were added individually to the as-received and preoxidized smelter slag, and the nonferrous tramp oxides were effectively partitioned into the resulting noncrystalline phase. Iron in the ferrous oxidation state was moderately soluble in the glass of reduced specimens but less soluble under oxidizing conditions. The solubility of iron oxide in phosphate glass exceeded the solubility of iron oxide in borate glass. Effective conversion of titanium oxide to rutile was not achieved in the high-iron commercial smelter slag, and 20 to 30 pct of the titanium remained as pseudobrookite, a mixed iron-titanium oxide.

Jan 1, 1973

By Richard F. Link

The objective of this report is to explain a statistical method for the summarization, organization, and classification of multivariate assay and other data from the mineral industry. Multivariate data are those characterized by several measurements at each data point, such as assay data from a mixed metal mine, or blast furnace data. A specific method of linear discriminant analysis, the Mahalanobis d2 procedure, is explained, starting from elementary principles; the d2 procedure enables many measurements at many data points to be studied by investigating the interrelationships among the data. The relation of linear discriminant analysis to other statistical methods for treating multivariate data, in particular the eigenvalue technique of factor analysis, is also explained. Example analyses are made on data from the Frisco mine, San Francisco del Oro, Chihuahua, Mexico. The data comprise assay values for silver, lead, copper, and zinc taken at some 19,000 sample points distributed into 91 groups.

Jan 1, 1967

By J. E. Tiffany, Z. C. Gaugler

In presenting this list of permissible explosives and blasting devices , the Bureau of Mines desires to call attention to pages 16 and 23 , outlining the conditions in use under which , and only under which , the explosive or blasting device is permissible . In view of publications recounting trade practice favoring the use of a blasting device without stemming , particular emphasis is placed upon condition 4 on page lt and condition 2 on page 23 .. An explosive or a blasting device enumerated in the permissible lists of this Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming .

Dec 1, 1943

By Max L. Glenn

As part of its goal to minimize requirements for mineral commodities through conservation and substitution, the Bureau of Mines conducted research to develop molybdenum as a potential substitute for superalloys containing the strategic and critical materials, nickel, chromium, and cobalt. Since molybdenum requires protection from oxidation at high temperatures, several complex oxides of the spinel and perovskite structure were investigated to determine which possessed the greatest potential for use as oxidation-barrier coatings. Two spinels (MgCr204 and MgA1204) and five perovskites (BaHfO3, YCrO3, NdCrO3, BaZrO3, and LaCrO3) were selected for testing. Various high-temperature prop¬erties that are important for oxidation-resistant coatings were examined, including diffusion rates of oxygen and molybdenum, recession (vaporization) rates, hardness, erosion resistance, sinterability, reactivity with molybdenum, and ease of application. From the evaluation of high-temperature properties, two spinels (MgCr204 and MgA1204) stand above the other oxides as possible coatings for molybdenum. However, laboratory coatings of MgCr204 at 1,360° C (2,480° F) are equivalent or inferior to currently available MoSi2 coatings; laboratory coatings of MgA1204 may be comparable under limited conditions to currently available MoSi2 coatings at the same temperature.

Jan 1, 1979

By BUREAU OF MINES

PLATINUM

Feb 1, 1922

By Arnold P. Pipilen

In a study of the principal factors affecting the transport of coal-water mixtures through a centrifugal pump and a pipeline, the interrelation between solids concentration, velocity, and pressure drop was established for a bituminous lump coal (minus 2 inch) in concentrations up to 48 weight-percent. An optimum concentration was found to exist for maximum capacity of a given pipe-line, and for minimum energy requirements per ton of coal. Coal size degradation by particle fracture took place in the pump; abrasion and attrition to form fines took place in both pump and line. A novel system of studying flow of solid-liquid mixtures in pipelines by the determination of relative sound intensities was developed.

Jan 1, 1966

By H. D. Kline

Manganese ores have been mined in the Batesville district since 1849. Although not continuous over the intervening years, production had totaled approximately 432,000 tons of manganese ore and ferruginous manganese ore to the end of 1953. The ores occur in deposits, essentially low in manganese content, distributed over an east-west belt 24 miles long and 4 to 8 miles wide, the core of which is about 6 miles north of Batesville, Independence County. Although the reserves of high-grade ores in the district are comparatively small, the large deposits of subgrade ores and low-grade manganiferous material comprise potential sources of supply of manganese that may have increasing future importance. The manganese occurs as primary oxide and carbonate minerals in relatively flat-lying limestone and shale formations in which they were originally deposited and as oxides in residual clays resulting from decomposition of the shale and lime-stone. Most of the deposits underlie from a few to over a hundred feet of sedimentary chert, but many occur in the residual clays on exposed slopes of chert-covered hills.

Jan 1, 1956

By D. Bienstock, J. H. Field, M. J. Lempel

A computer program is presented to perform the detailed and numerous calculations required for determining the interface temperatures and steady - state heat flow through a furnace wall composed of several refractories in layers . A method is developed that will allow the designer to determine the various thicknesses for each refractory layer to minimize either the total wall thickness or the cost of the wall per unit of area . A sample problem is presented and analyzed to illustrate the techniques involved .

Jan 1, 1964

By Heine Kenworthy

"INTRODUCTION In 1930 the Shenandoah-Dives Mining Co. near Silverton, Colo., put into operation a newly erected, 300-ton selective flotation plant to mill complex ores from its nearby mine. The operation was a steady producer and was enlarged to treat 600 to 800 tons a day. In 1942 the company opened and started milling an area in the mine containing semioxidized ore. The valuable mineral content of this ore was considerably higher than in, the straight sulfide ore previously handled alone. The mixture of clean sulfide and semi-oxidized ore was difficult to treat; consequently, tailing losses, especially with respect to lead, were high. A few years later, in order to study the possibilities of obtaining higher recoveries by a modification of the mill flow sheet, a 1,200-pound sample of mill, feed, taken over a period of several days by the company, was submitted to the Mississippi Valley Experiment Sta¬tion for testing-. Although this sample proved to contain more than twice as much lead as the average yearly mill feed, the same problem of recovering the oxidized values was present.A résumé of the ore-dressing treatment used in the Shenandoah-Dives mill follows. After crushing, the ore passes through a ball mill, the minus 5-mesh discharge of which is distributed to three tables. A finished lead concentrate is made on the tables, and the table tailing goes to the classifier which is in closed circuit with the ball mill. The classifier overflow is treated -by flotation to obtain a bulk sulfide concentrate at a relatively coarse size. The bulk concentrate is thickened and reground to about 95 percent minus 325-mesh before flotation treatment to separate a lead-copper and a zinc concentrate. A typical monthly average showed that the table concentrate contained about 45 percent lead, 1 percent copper, 4 percent zinc, 12 ounces of gold, and 40 ounces of silver; that the lead flotation concentrate contained '35 percent load, 6 percent copper, 7 percent zinc, 3.5 ounces of gold, and 50 ounces of silver; and that the zinc flotation concentrate contained 2 percent lead, 0.5 percent copper, 60 percent zinc, 0.15 ounces of gold, and 4 ounces of silver. Recoveries in salable products were roughly b5 percent of the lead, 70 percent of the copper, 45 percent of the zinc, 85 percent of the gold, and b5 percent of the silver."

May 1, 1948

By Warren D. Longwill

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Jan 1, 1981

By Denise A. Herzog

The U.S. Bureau of Mines conducted a study of cyanide leach technology used in Alaska's mineral industry from 1987 through 1990. Literature and cost data were obtained for mines in the contiguous United States, Canada, and Alaska that use cyanide to recover gold and silver. The data was compiled in an effort to evaluate the economics and conditions associated with cyanide use in Alaska. This report discusses heap leaching methodology and evaluates a "typical" heap leach operation in Nevada and compares the results of the Nevada operation to an analogous hypothetical mine in Interior Alaska. Five daily tonnage rates were analyzed for both the Nevada and the Alaska operations to evaluate the spectrum of economic possibilities. The discounted cash flow rate of return (DCFROR) for each production rate was then evaluated in terms of recoverable metal value (RMV). The Nevada RMV for each production rate was then compared with its Alaskan counterpart, and the results averaged. The Alaskan production costs are an average of 1.71 times greater than costs associated with mining in Nevada at a 0% DCFROR. At 15% DCFROR, costs in Alaska are 2.01 times greater than those in Nevada. Costs are higher in Alaska because of the shorter leaching season, increased labor and transportation costs, and heavier precipitation and vegetation.

Jan 1, 1991

By Charles K. Rose

The Cebolla Creek titaniferous iron deposits near Powderhorn in southern Gunnison County, Colo., were examined by the Federal Bureau of Mines as part of an overall program to investigate the Nation's titanium and iron resources. The deposits occur around the periphery of the Iron Hill stock, which underlies an area of about 12 square miles. Concentrations of magnetite, ilmenite, and perovskite arc localized along fractures in the pyroxenite stock. Mineralogical studies of composite surface samples collected in 1956 showed that most of the iron is present in ilmenite-bearing magnetite. Perovskite is the chief titanium mineral in the magnetite-rich and augite-rich types, and sphene is the principal titanium mineral in the placer material. The mica-rich rock contains approximately equal amounts of perovskite, ilmenite, and sphene.

Jan 1, 1960

By E. C. Lane

During the past 15 years the Bureau of Mines has made and published several hundred analyses of typical petroleums and has developed a system of interpreting the analyses and of classifying crude oils. In describing crude petroleum frequent reference is made to the "base" of the oil, a usage the petroleum industry has found convenient. As part of its general study of the characteristics of crude oils, therefore, the Bureau of Mines has developed a system of classifying them according to "base." This system as first published in 1927 was limited to four classes and in its original form is no longer considered adequate. Since the system was first published the Bureau has analyzed a large number of crude oil, including representative samples from nearly every important producing field in the world, and has found that the system of classification could be revised and amplified to advantage. The revised system is presented herein.

Jan 1, 1935

By B. E. Davis

The Bureau of Mines conducted tests on samples of two Florida phosphate slimes t6 devise a technique to recover phosphate currently dis-carded because of its fine size. A flotation technique was devised to recover the phosphate contained in two fractions of each slime: the plus 37um fraction and the plus 20-um fraction. The technique involved conditioning the flotation feed with sodium silicate and a fatty acid-fuel oil emulsion, floating a rougher phosphate concentrate, and cleaning the concentrate in two cleaner stages with sodium silicate added to each for gangue depression. Concentrates containing 21.0 to 32.3 pct P20S were produced with recoveries of 68.1 to 84.2 pct of the P20S con-tained in the flotation feed.

Jan 1, 1987

By A. Viksne

A series of tests were conducted by the Bureau of Mines to determine the best means of reducing noise generated by the detonating cord that is utilized for trunklines in quarry blasting. Ten different types of detonating cord were tested and evaluated for their acoustic qualities. The results of the investigation showed that noise levels produced by "low-core-load-per-foot" detonating cord "not covered" were lower than those produced by "high-core-load-per-foot" detonating cord covered with 6 inches of unconsolidated material.

Jan 1, 1972

By C. C. Furnas

In the course of an investigation3 of the flow of gases through beds of broken solids the author obtained a number of data .on the specific volume of beds of broken solids of variously mixed sizes. A mathematical theory of the limiting conditions has been developed and some generalizations have been made for intermediate cases. A more definite knowledge of the relation between space occupied and size composition would be valuable to all those who are handling large quantities of broken materials. Such knowledge might be advantageously applied to the operation of a coke oven. For example, the output of the oven depends in general upon the number of pounds of coal which can be put in the oven at charging. It is known that the capacity of one battery of ovens was increased several per cent by slightly increasing the proportion of fine material in the charge.

Jan 1, 1928

By R. E. Campbell

Uranium metal of improved purity was prepared by electrorefining commercial magnesium-reduced uranium in a molten sodium chloride-uranium trichloride electrolyte. The best operating conditions for the preparation of refined metal were established as follows: an electrolyte containing 8.7 to 13.3 weight-percent uranium; initial cathode current densities from 300 to 1,500 amp/sq ft; and a molten salt temperature of 860° C. Ingots produced from electrorefined uranium crystals prepared with these operating conditions were substantially free of metallic impurities. The only impurities in the refined and consolidated metal were present in low or undetectable amounts.

Jan 1, 1965

By Tom Retka

This three volume final report summarizes the activities and conclusions of this contract. The objective of the contract was to develop noise control modifications on a retrofit basis, for auger miner coal-cutting systems. Manuals were prepared to assist mine shop personnel in retrofitting the auger miner with these noise controls. Final Report Volume I - Details all vibration and acoustical tests conducted in develop¬ment of the noise controls. Final Report Volume II - Noise Control Modification Manual for the Jeffrey 100-L Auger Miner describes the various noise control modifications to the auger miner, along with fabrication procedures, cost and vendor information. Final Report Volume III - Noise Control Modification Manual for the Jeffrey 94-L Bridge Conveyor describes the various noise control modifications to the bridge conveyor, along with fabrication procedures, cost and vendor information.

Jan 1, 1978

By Paul Hatmaker

Pumice and pumicite are siliceous volcanic substances quite similar in chemical composition , but somewhat different in physical properties , manner of formation , and mode of occurrence . Production in the United States has increased from 23,271 tons valued at $ 94,943 in 1910 , to 56,843 tons valued at $336,099 in 1930. Both pumice and pumicite are included in these figures as it has been impractical to collect statistical data on the separate commodities .

Mar 1, 1932