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By M. W. Von Bernewitz

Corduroy is used for saving gold in small Land large milling plants throughout the world. Investigations by the Metallurgical Division of the Bureau of Mine indicate that corduroy blankets, used with or without a trap or jig in the mill classifier circuit, often are effective in concentrating gold and sulfides, especially if the gold does not amalgamate readily and if not enough sulfides are present to warrant the use of a shaking table, flotation cells, or cyanide plant. Most cold-mining countries include several or many small miner, that produce siliceous ores low in sulfides and gold, which can easily be amalgamated or caught in traps or jigs or on corduroy and shaking tables. At these mines the ore is crushed by stamps or bill mills, and the flow sheets include plates, flotation cells, and cyanide treatment, yet probably nearly as much of the pair minerals may be recovered by the less expensive plant. A well-known western maker of mine and mill equipment asserts, as the result of considerable observation of installed plants, that old and other valuable minerals should be caught as soon as they have been released by a mill, end recommends jigs to do this. A supplier of corduroy has informed us that at some mines this material is being replaced by jigs that catch gold as fine as 400-mesh. But for the small operator, inexpensive equipment such as a corduroy table may be better adapted and give a good recovery of gold and associated minerals.

Jan 1, 1939

By A. W. Frolli

This paper, describing the mining and reduction methods and costs at the Oceanic quicksilver mine, is one of a series of similar reports being prepared by the Bureau of Mines on various mines in the United states. The property, which is owned and operated by the Anglo American Mining Corporation, Ltd., is 5 miles east of Cambria, San Luis Obispo County, Calif. It lies in a region of steep hills and sharply incised canyons on the west slope of the Santa Lucia Range at an elevation of about 500 feet above sea level. The climate is ideal for living and operating conditions. A 40-mile paved highway connects the mine with San Luis Obispo, the nearest convenient railroad town.

Jan 1, 1937

By Donald F. Reed

The bauxite deposits of Tippah and Benton Counties in northeastern Mississippi were developed by drilling as a part of the investigation by the Bureau of Mines of the domestic sources of supply of aluminum. The primary purpose of investigations of this nature was to provide essential information to the war agencies of the United States Government and to assist owners and operators of mining properties in the production of minerals vital to the prosecution of the war. These reports are based upon the field work of the Bureau of Mines and upon data made available to the Department from other

Jan 1, 1948

This report was prepared by Jacob Tolsma and Arnold N. Johnson of the Uniroya 1 Research Center, Wayne, New Jersey. The valuable assistance and suggestions of the project officers, Mr. Ronald D. Hill, Dr. David R. Maneval and Mr. John J. Buscavage is gratefully acknowledged. The authors are grateful to the following Uniroyal personnel: Mr. Daniel Shichman, manager of Engineering Research, and Dr. Emmanuel G. Kontos, manager of the Polymer Physics Research for their direction, encouragement and suggestions regarding the experimental work, and Mr. Mark Olson for the design of the hollow auger soil sampler. We also wish to gratefully acknowledge the efforts and contributions of ideas proposed by our consultants, Dr. Frank T. Caruccio, assistant professor of geology at State University College, New Paltz, New York, and Dr. Pa Ho Hsu, associate professor of soil chemistry, Rutgers University , New Brunswick, New Jersey.

Jan 1, 1972

By Edwin M. Murphy

Methods are described for filling underground cavities remotely with dry material pneumatically injected through a borehole to seal openings, prevent air movement, and reduce subsidence; this often brings underground fires under control by limiting the access of air. Large-scale tests were made in the Bureau of Mines Experimental Coal Mine, Bruceton, Pa., in an operating mine, and in an abandoned Pennsylvania mine. Supplemental trials were made aboveground in galleries and in the laboratory. The parameters studied include horizontal and inclined passageways, obstructions in the entry, water leakage into the borehole, dry material, and grout and slurry mixes. The materials studied were fly ash, crushed and pulverized limestone, and sand. Best results were obtained with dry fly ash, though satisfactory seals were obtained with the other materials. When a borehole is dry and ends at an open void, casing is not necessary. If more than 5 gpm of water flows in the borehole, if the void contains loose debris, or if coarse material is injected, a material feedpipe should be inserted through the borehole. Fly ash was most suitable for remote filling because of its low angle of repose (8°) and its good flow characteristics. The depth of borehole through which the fly ash is injected has no appreciable effect on the filling operation.

Jan 1, 1968

By G. V. Sullivan, G. F. Workentine

Beneficiation studies were conducted by the Bureau of Mines on three samples of low- grade chromite - bearing material from the Stillwater complex of Montana . The objective of the study was to develop methods for recovering chromite from low- grade materials to improve the domestic reserve situation . Samples were obtained from the three largest deposits in the district , Mouat , Benbow , and Gish . The chromic oxide ( Cr₂ 0 ) content of the ore and of the chromite was about the same in each of the samples . The major gangue constituents ranged from clean olivine in the Mouat sample to such altered minerals as serpentine and talc in the Benbow and Gish samples . Tabling , flotation , high- tension electrostatic separation , and combinations of processes were applied to each ore . Treatment of the Mouat sample ( 9.95 percent Cr₂ 0 ) by high- tension electrostatic separation , a combination of tabling and high- tension electrostatic separation , and tabling with middling retreatment resulted in concentrates that graded 42.8 , 42.0 , and 40.7 percent Cr₂03 at chromium recoveries of 85 , 86 , and 84 percent , respectively . Other techniques were less selective . 2 The Benbow sample ( 7.75 percent Cr₂0 ) responded most selectively to tabling with middling retreatment and a combination of tabling and hightension electrostatic separation to produce concentrates of 40.1 and 39.5 percent Cr₂g with each process having a chromium 2 recovery of 69 percent . Response of the Gish sample ( 8.04 percent Cr₂03 ) to the various concentration techniques was about the same as that of the Benbow sample , but in general , somewhat less selective . A combination of tabling and high- tension electrostatic separation resulted in a concentrate that contained 71 percent The Mouat mine was reopened in 1953 when the American Chrome Co. contracted with the Federal Government to produce 900,000 tons of chromite concentrate . The ore , averaging 20.2 percent Cr₂03 , was treated by tabling to produce a 38.5 - percent Cr₂ O concentrate.

Jan 1, 1964

By Ben E. Lindsly

The study of "bottom-hole samples follows in natural sequence the study of samples obtained under high pressures at the well heads of flowing wells. The principal object of this phase of gas-solubility research, started actively in January, 1930, was to gain a more accurate knowledge of the physical and chemical characteristics of the oil-gas mixtures that exist in natural reservoirs.. In possession of actual data regarding the condition of the oil; the quantity of gas liberated from solution upon dimunition of pressure; and the relative volumetric proportions of gas to oil at various pressures throughout the flow string in a well, it should be possible to predict, with a fair degree of accuracy, That physical changes these mixtures would undergo throughout the life of a pool. Such information not only is important in designing flow strings in flowing Tells but is important also in solving problems relating to pumping efficiency and the power required for pumping. Although certain fundamental data were obtained in the study of samples taken at the well head, "bottom-hole" samples are more representative of subsurface mixtures of oil and gas because they are obtained at reservoir temperatures, and before the oil has had the opportunity of intermingling with extraneous gas; that is, gas which either was not in solution originally, or which was liberated from solution at higher pressure, and later became mixed with the original undissolved gas.

Jan 1, 1933

By J. S. Webb

This is one of a series of papers dealing with mining methods, practice, and costs be¬ing published by the United States Bureau of Mires. In this paper a description of the mining practice in vogue at the Braden unit of the Kennecott Copper Corporation is undertaken. PRODUCTION At present (1931) the entire production of ore is being obtained from the Teniente mine. The miring method in use is an adaptation of block undercutting which has been a development of the stoping and pillar caving experience obtained at this property. Improvements in mining practice are constantly being made.

Jan 1, 1932

By Mark Sheppard

[Considerable research work hi been done on secondary crushing and coarse and fine grinding, and the literature on the general subject of Crushing contains many references to the work of investigators on the laws governing end the factors entering into the economical production of fine materials. However, little information on primary crushing in available The literature deals mainly with problems and practices in ore dressing, end in this field the engineer or investigator is concerned largely with the production of fine material and the unlocking of minerals in the ore. Under such conditions close control of screen sizes of primary-crusher products is a secondary consideration and has received very little attention.]

Jan 1, 1938

By I. D. Shah

The Bureau of Mines investigated the sequence of principal chemical reactions taking place during the roasting of covellite (CuS). Practically all covellite is converted to digenite (Cul.SS) before oxidation to Cu20 begins. Part of the Cu2O is then converted to CuO, which in turn forms CuS04 through CuO?CuS04 as an intermediary. CuS04 and CuO'CuS04 decompose at 600° to 700° C to yield CuO and S03 (g) as final products. An overall mechanism is proposed for chemical reactions occurring at different interfaces of partially oxidized CuS pellets.

Jan 1, 1970

By D. W. Bridges, S. R. Borrowman

Thorium and yttrium oxides were recovered from siliceous ores of the Powderhorn , Colo . , area . Processing comprised ( 1 ) acid curing and subsequent ( 2 ) acid baking , ( 3 ) leaching , and ( 4) solvent extraction of thorium , using a primary alkylamine , and yttrium , using di - 2 - ethylhexyl phosphoric acid . About 95 pct of the contained thorium and yttrium was recovered from ore containing 1.2 pct Th02 and 0.5 pct Y₂ 03. The thoria product was 99 pct Tho ; the yttria product was 77 pct Y₂ 03. A 150 - to - 1 concentration ratio was effected on the latter , but some contaminating lanthanon - group oxides remained .

Jan 1, 1964

By G. W. Birge, D. E. Wolfson, J. G. Walters

Seventeen samples were carbonized by the BM -AGA pilot - plant test method and in industrial ovens . Chemical and physical properties of the samples were determined , and the physical properties of the cokes prepared by the two methods were compared . Since the capacity of the plants from which these samples were obtained is about 30 percent of the 1959 total for the United States , the data given in this report are indicative of the chemical and physical properties of blends used to produce industrial cokes and the acceptable chemical and physical properties of the resultant coke .

Jan 1, 1964

By E. G. Baglin

The Bureau of Mines devised a procedure for selectively extracting platinum-group metals (PGM) and gold from Stillwater Complex flotation concentrate. The Stillwater Complex is the only major U.S. PGM resource. Development of a suitable extraction technique will contribute to its exploitation. The concentrate was roasted at 1,050° C to convert host base-metal sulfides to oxides and the PGM from sulfide minerals to their elemental states. The roasted concentrate was preleached with dilute sulfuric acid to remove easily soluble gangue minerals. After pre-leaching, the concentrate was slurried with 6M HCI and leached at ambient temperature and pressure with a strong-oxidizing agent. Hydrogen peroxide, chlorine, sodium hypochlorite, nitric acid, and a persulfate salt were the oxidants investigated. The two-stage leaching scheme ex-tracted up to 97 pct of the platinum, 92 pct of the palladium, and 99 pct of the gold from the roasted concentrate. The base metals were not solubilized and reported to the residue. No attempt was made to devise a procedure to recover the copper and nickel because they comprise less than 5 pct of the value of the concentrate. Viable techniques for recovering the precious metals from the pregnant solution were sulfide precipitation, cementation with nickel, or adsorption on activated carbon.

Jan 1, 1985

By T. L. Marchewka

As part of its program to conserve the Nation's natural resources by developing improved performance materials, the Bureau of Mines, U.S. Department of the Interior, in cooperation with the U.S. Department of Energy, has conducted an investigation of materials of construction able to withstand the high temperature and hostile environments encountered in coal gasification units. Refractory pipe liners are required when extremely hot gases or abrasive solids are transported between processing units in the gasification plants. One promising technique for producing refractory pipe (or refractory pipe liners) is centrifugal casting. For this study, the effect of processing variables such as workability, additives, reinforcement and spinning time, and centrifugal force were evaluated using four commercial refractory concretes. In addition, data on characteristics such as strength, density, abrasion, and spalling resistance of 5-inch-diam refractory pipe were developed. Techniques for forming large-diameter (19-inch) refractory pipe also were evaluated. The test results indicated that all four refractory concretes could be made into strong, homogeneous pipe, but that optimum casting parameters had to be determined for each specific composition. The investigation revealed that the major controlling factor in the production of the centrifugally cast pipe was the workability of the refractory concrete.

Jan 1, 1979

By T. F. Mitchell

During the investigation or the occurrence of manganese deposits in western United States, Bureau of Mines' examining engineers collected samples from four manganese properties in the Death Valley region, California. These were supplemented by samples submitted by owners of two other properties in the same area. Extensive laboratory tests were made to determine the, amenability of the ores to standard ore-dressing concentration methods. A small sample of high-grade oxide manganese ore from the McWhinney property, San Bernardino County, Calif., was submitted by the owner. Although the sample would sinter directly to plus 48 percent manganese grade, it appeared probable that the ore, if mined in quantity, would be lower in grade and would require beneficiation. Therefore, testing was conducted to remove the chief gangue constituent, calcite. The National Resources, Inc., property (also known as the old Owl Hole mine) is in the Owl Hole Springs district, I mile from Owl Hole Springs, San Bernardino County, Calif., near the southwest corner of Death Valley National Monument. The ore deposits occur as small lenses or ,pockets, evidently .replacements in limestone and granite. Laboratory work was done on a representative sample of orb procured by Bureau engineers.

Jan 1, 1949

By R. E. Peterson

A reduction roasting/magnetic separation/flotation process for beneficiating oxidized taconite from the western Mesabi iron range in Minnesota was evaluated in a Bureau of Mines research program to insure an adequate supply of raw materials for future ironmaking and steelmaking needs. The research was performed on a sample containing 35.4 pct iron and representing a deposit of approximately 2 billion tons of raw materials. An average of 1,419 lb of oxidized taconite and 37 lb of lignite reluctant per hour were fed to a 35 -foot rotary kiln in which the iron oxides were converted to artificial magnetite. The kiln was heated with pulverized lignite and natural gas. Most of the dust collected from the kiln exhaust gas was pelletized and recycled to the kiln. Magnetic separation and cationic flotation of the roasted material in a 900-lb/hr pilot plant produced a concentrate analyzing 67.9 pct iron and 4.9 pct silica and containing 69.2 pct of the iron in the kiln feed.

Jan 1, 1981

By Donald O. Rausch, Robert H. Merrill, David W. Wisecarver, S. Jackson Hubbard

Results are reported for stress - relief borehole - deformation measurements made in three underground openings near open - pit mines in the Ruth mining district , Nevada . A total of 134 deformation measurements were made in 8 boreholes . These measurements determined the regional stresses in the horizons above , below, and at the elevation of nearby open - pit mine floors ; knowledge of these stress conditions is considered essential information relative to certain aspects in the designing of stable pit slopes . The determinations indicate that the stresses in the district are due to the gravitational load of the overburden in a confined stress field .

Jan 1, 1964

By W. A. Stickney

This report summarizes the results of laboratory tests of five samples of low-grade phosphate ores from Idaho. The laboratory test work has demonstrated that by grinding, desliming, and flotation a portion of the siliceous gangue can be removed. The highly carbonaceous ores responded successfully to treatment after preroasting, to produce a plus-30-percent-P205 product. It has been found that highly siliceous ores, as represented by the samples treated, are more readily amenable to concentration than ores high in calcium carbonate. Of the five samples tested, four were amenable to concentration to a product containing over 30 percent P205. One sample, from the Conda, second bed, was not amenable to mineral-dressing treatment to produce a plus-25-percent-P205 product.

Jan 1, 1955

By K. F. Anderson

The increasing number of oil-productive reservoirs in the Ellenburger formation has emphasized the need for information pertaining to the hydrocarbon recoveries that may be obtained from such reservoirs. Most of the space available for accumulating hydrocarbons in the Ellenburger formation is derived from fractures, which makes it difficult to estimate reserves or probable recoveries. The Ellenburger reservoir in the Big Lake field was selected for study because it is one of the few near-depleted reservoirs in the area. The experience gained in operating and developing this reservoir has been and should continue to be a helpful guide to operators both in predicting recovery and establishing methods of development and operation In similar reservoirs. Development and production data were gathered from different sources. The writers have compiled and interpreted these data to estimate the ultimate recovery of hydrocarbons. In addition to the estimates of ultimate recovery, the report contains sample calculations and estimates of theoretical recovery based on different methods of operation. The calculations presented in this report indicate that the Ellenburger reservoir is 95 percent depleted and that the ultimate recovery of hydrocarbon liquid from the oil reservoir and gas cap combined will he 4-0 barrels per gross acre-foot of reservoir rock. An estimated 32 barrels of condensate per gross acre-foot of reservoir rock in the gas cap has been recovered, and the estimated ultimate recovery of crude oil will be 47 barrels per gross acre-.foot of rock in the crude-oil reservoir.

Jan 1, 1954

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing gypsum mining and crushing methods and costs at various operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs may in many instances cause embarrassment to individual operators as well as to the industry as a whole. On the other hand, operating costs are essential to a technical discussion and study of the methods employed. The attention of the reader is called specifically to this differentiation so that there may be no misunderstanding of the scope of the cost tabulation. This paper deals specifically with the mining and crushing methods employed by Victor Plaster, Inc., Victor, Ontario County, N. Y. The maximum annual production capacity of this company is 150,000 tons of crushed gypsum. The methods and practices employed arc typical of those followed in the gypsum mines in western New York State. The shaft is, perhaps, the deepest and the thickness of the gypsum mined is above the average for the section.

Jan 1, 1937