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By David M. Hopstock, Jose M. Pastrana

The magnetic susceptibilities of samples of natural and artificial hematite and natural goethite were measured by the Faraday method as functions of temperature, magnetizing field strength and particle size. All samples showed weak ferromagnetism, which accounted for large variations in susceptibility with field strength and particle size. Three probable sources of the weak ferromagnetism were identified.

Jan 1, 1978

By C. W. Spencer, R. A. Rummel, F. N. Rhines

SPECIMENS of five cast Cu-Bi alloys, containing 4.68, 0.53, 0.043, 0.0064, and 0.0025 wt pct Bi and cast pure copper were subjected to a bend test to determine their relative ductility. Using metallo-graphlc methods the structures of the fractured surfaces were compared with those of the polished cross sections. Embrittlement was found to be associated with the presence of a second phase in the grain boundaries although, in the lower bismuth

Jan 1, 1958

By R. E. Stewart

The major mining companies of the world all face the problems associated with investing in new mining ventures. In particular, investment in foreign countries - whether these are advanced or developing countries - requires careful consideration. A thorough analysis of all the possible risks must be undertaken, so that realistic decisions can be made. Some of the points to be considered are outlined in this paper.

Jan 1, 1977

By Robert E. Reed-Hill, Edward R. Buchanan

A recent paper by Adams and vreeland30 describes dislocation density changes in zinc as a function of shear strain. The dislocation density was determined with the aid of an etching technique previously described by Brandt, Adams, and Vreeland.31 However, comparison of dislocation densities obtained by electron microscopy and this etching technique are not in good agreement, as will be shown below. Several zinc crystals of 99.999 pct purity were grown in air using a modified Bridgman technique.' These were annealed in air a 400°C for 1 hr and

Jan 1, 1969

By A. S. C. Owili-eger

The computer-aided simulation model re¬ported here is an extension of the one developed by the author while at The Pennsylvania State University. The present model, however, includes consideration of the deformability and secondary fracturing of the porous system. The modifications enable simulation of multiphase shallow unsaturated-saturated and/or artesian ground water systems in dynamic mining environments. The model has been validated, verified, and evaluated on a number of field case studies and the results have been excellent.

Jan 1, 1984

By J. W. Lewis

This review covers that portion of the area between the Llano mountains and the Red River which lies between Fort Worth and Abilene. The counties and fields included are listed in Tables 1 and 2. During 1929 there was a marked lull in both prospecting and development in this part of Texas. Archer, Coleman, Cooke, Wilbarger and Young were the counties most active. The total gross production of the year was 52,611,000 bbl., 3 per cent. more than for 1928. The production of the Coleman, Cooke-

Jan 1, 1930

By P. Schwed

IN determining the mechanism responsible for sintering, the most direct procedure available is the comparison of the observed time and temperature dependence of the process with the dependence to be expected upon the basis of each conceivable mechanism. This was done by Kuczynskil who, in treating the mechanism of surface diffusion, postulated, in effect, that the concentration gradient of vacancies is different from zero only within the neck. This procedure was recently questioned by Cabrera' who assumed, on the contrary, that diffusion occurs only in the region outside the neck. In the present note, the calculations are performed without restriction on the region of diffusion. To carry out this objective it is first necessary to

Jan 1, 1952

The Mining Enforcement and Safety Administration has called attention to the increasing frequency of accidents occurring during mine maintenance and repair tasks in a recent publication. Data from the agency's Health and Safety Analysis Center have been compiled and presented in a report titled "Analysis of Injuries Associated with Maintenance and Repair in Metal and Nonmetal Mines,"* a booklet aimed at answering four questions: (1) Which pieces of operating equipment are most frequently involved in maintenance accidents; (2) Which maintenance functions are the most hazardous; (3) Which tools are most often associated with injuries; and (4) What is the comparative hazard of welding or flame cutting vs. mechanical or electrical maintenance functions.

Jan 3, 1978

By Alexander L. Holley

IN order to put sufficient work on steel ingots for rails, they must be reduced from about 12 inches square. As this cannot be done at one heat, they are first drawn down to about 7 inches square, and then reheated and rolled into rails. This first reduction or " blooming," is usually done in this country in a 30-inch 3-high rolling-mill, with movable rolls, so as to get several reductions in each set of grooves. The first of these mills has been running at the Troy Steel-works above a year, with great success. Another at the Cambria Iron

In May 1952, a total grant of $750 was made for the establishment of a scholar- ship in petroleum engineering for the academic year of 1952-1953, to be ad- ministered by AIME and to be known as the AIME-Socony-Vacuum Scholarship in Petroleum Engineering It will be given In the general field of petroleum engineering The scholar selected must be an undergraduate who is expected to complete academic work during the period of the award In other words, upon completion of the award period, the recipient is expected to be ready to enter industry The establishment of this Scholarship and the selection of the Scholar there under will Impose no ob1igation upon the Scholar or upon Socony- Vacuum with respect to employment The Scholarship is being administered by the Mineral Industry Education Division of the AIME

Jan 1, 1952

BESIDES air -water, sulphur, salt, coal, and lime-stone are the key nonmetallic raw materials used by the chemical industry and each came in for attention at the AIMF, Industrial Minerals Division meeting at Morgantown. W, Va., Sept. 13 to 15. West Virginia is a growing chemical producing area with sites along the Ohio and Kanawka Rivers being favored because of power, accessibility of raw materials (many in the State), water supply, and transportation.

Jan 10, 1951

Coal was produced in this state, by white men, at an earlier date than in any state west of the Mississippi River, and for many years its production was larger than that of any state in that area. The coal immediately adjacent to St. Louis was mined commercially earlier than elsewhere because of a ready market which could be reached by teams. Generally the coal seams are more or less "spotty" in character, and in many places openings made in thick coal could only be mined for a few years. All of the data available from state survey reports, county histories and a few other sources are shown in Table 66.

Jan 1, 1942

By H. H. Pentz

THIS paper gives the derivation of a practical formula for the calcu-lation of slopes in seismic reflection prospecting. The derived formula is an approximation and can be used where the slope of the reflecting horizon is less than 250 ft. per 1000 and the depth to the reflecting horizon is greater than 2500 ft. The slope of sediments in oil regions is generally considerably less than 250 ft. per 1000. This is particularly true of the Gulf Coast, with the exception of the salt domes, which usually have the sediments at a greater slope than 250 ft. per 1000.

Jan 1, 1937

DAVID THOMAS 1871 R. W. RAYMOND 1872-1874 A. L. HOLLEY 1875 ABRAM S. HEWITT 1876 T. STERRY HUNT 1877 ECKLEY B. COXE 1878-1879 WILLIAM P. SHINN 1880 WILLIAM METCALF 1881 RICHARD P. ROTHWELL 1852 ROBERT W. HUNT 1883 JAMES C. BAYLES 1884-1855 ROBERT H. RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B. POTTER 1888 RICHARD PEARCE 1889 ABRAM S. HEWITT 1890 JOHN BIRKINBINE 1891-1892 H. D4. HOWE 1893 JOHN FRITZ 1894 J. D. WEEKS 1895 E. O. SPILSBURY 1896 THOMAS M. DROWN 1897 CHARLES KIRCHHOFF 1898

Jan 1, 1943

By W. R. Webster

Opinions still differ widely concerning the requirements, chemical and physical, which should be expressed in specifications for steel rails, in order to secure results satisfactory to both manufacturers and purchasers.

Jan 1, 1902

By David A. Rice

This note describes a simple, rapid technique for measuring the apparent volume and density of individual bits of porous materials such as iron ore pellets or pieces of coke. The method consists of determining the weight recorded on a balance when a particle is depressed below the surface of mercury, and calculating the apparent volume from the known density of mercury. The apparent density is calculated after weighing the particle in air. The method is particularly well suited for applications where a great number of determinations are to be made. An additional benefit is the minimal handling of the mercury. In any event, the usual recommended safety precautions should be adhered to.

Jan 1, 1982

BULLETIN 177. The decline and ultimate production of oil wells with notes on the valuation of oil properties, by C. H.- Beal. 1919. 84 pp., 4pls., 80 figs. BULLETIN 179. Abstracts of current decisions on mines and mining, reported from September to December, 1918, by J. W. Thompson. 1919. 166 pp. TECHNICAL PAPER 214. Motor gasoline; properties, laboratory methods of testing, and practical specifications, by E. W. Dean. 1919. 33 pp., 2 figs. TECHNICAL PAPER 219. Combustion and flue-gas analysis, by U. S. Fuel Administration. 1919. 12 pp., 5 figs. TECHNICAL PAPER 223. Cost-keeping for small metal mines, by J. C. Pickering. 1919. 46 pp. Only a limited supply of these publications is available for free distribution. Publications should be ordered by number and title. Applications should be addressed to the Director of the Bureau of Mines, Washington, D. C.

Jan 7, 1919

By C. R. Tinsley

A strictly limited number of specialist project finance banks exists, with the necessary specialist personnel able to address project cost-competitiveness, cost and commodity forecasting, joint venture negotiations, and completion and sales undertakings. Different techniques of internal bank appraisal are applied, with the usual equity investment project valuation criteria being seldom useful for loan assessment purposes. Company attention paid to the preparation of a sensitivity structured bankable presentation can prove most effective for securing development project finance. Substantial scope is possible for savings of time and money.

Jan 1, 1985

TENDENCIES toward nationalization grew noticeably stronger in some areas. Late last fall Bolivia took over the tin mines of four foreign operators and handed them a bill for a fabulous amount claimed for damages. In the same breath, the price Bolivia offered to pay for the mines appeared to many to be slightly ridiculous. Many engineers felt that the country would not be able to run the mines successfully. Even if they could, some thought that the Bolivian Government would gut the orebodies in an attempt to get at rich deposits for high profits, leaving the lean ores in unmineable condition.

Jan 2, 1953

W. M. CORSE, Mansfield, .Ohio.-We have sometimes seen in indi-vidual tests ultimate tensile strengths ass high as 55,000 lb. per. sq. in. being attained under electric furnace practice. These results, of course, average much lower than that, but with better methods of melting, can we hope to get the strength up to somewhere near the figure attained by these individual tests? C. P. KARR.--Yes, because with the electric furnace you can lessen the oxidation by means of the impurities always found in the melting. But one of the most important things in making 88-10-2 bronze of this class is to use a core-sand mold with a very open grain, so that the

Jan 12, 1919