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By Robert L. Akre

When Marco Polo visited China in the 13th century, no one knew what black powder was except the Chinese: they knew enough to make dazzling fireworks with it. But the realization that black powder could also do useful work came much later and, like all important discoveries, it altered the course of history. It was in the 14th century that black powder was first used to break rock in a very crude way: there were no drills and the powder was simply poured into cracks and exploded by setting it afire. Because its energy value was pretty low, the need for something more powerful was felt when the industrial revolution arrived.

Jan 6, 1976

By G. Don Sullivan

Surface mine operators have organized a voluntary group known as the Mined-Land Conservation Conference for the specific purpose of developing and expanding reclamation programs on mined land. As a part of the Conference program, a Voluntary Industry Program was adopted and subscribed to by its membership. This program stated: "The basic approach to a sound conservation program is the restoration of mined land to its most practical and productive use within the shortest possible time . . . reclamation of mined lands, including planting to grasses or tress, should be done on a planned basis, under technical guidance by personnel trained in this field."

Jan 7, 1965

By Leslie C. Richards

The competitive position of producers of industrial minerals depends upon the delivered price of their product. Freight charges are a major factor in the sales to consumers. A comparison of freight rates on movements of limestone and silica rock in the Pacific North-west shows a wide variance in mills per ton mile for like hauls, thereby favoring some localities over others.

Jan 2, 1950

By H. Carroll Weed

By caving a block into the workings of its open pit and using the block as an ore transfer, the Inspiration Consolidated Copper Co. has solved a transportation and sizing problem, making possible a great expansion of open-pit methods as applied to Inspiration ore- bodies.

Jan 9, 1953

By C. A. Rowland, R. C. Nealey

Wet grinding rod mills have been used for 50 years to grind ores and to make specification sand. The application of wet grinding rod mills is well understood. Until recently, there have been very few installations of dry grinding rod mills. The selection of dry grinding rod mills follows the basic principles established for the selection of wet grinding rod mills. The basic Bond Formulae1 [ ] is used to select mills when using grindability test results as the basis for selection. W is multi- plied by the 1.3 wet to dry grinding factor established from wet and dry ball milling experience, and then by any other applicable inefficiency factors.1 Dry grinding rod mills have also been selected by scaling up bench scale continuous rod mill tests and pilot plant tests.

Jan 12, 1968

By K. S. Choi, B. S. Shin

The adsorption characteristics of sodium silicate on scheelite, calcite, and fluorite minerals were investigated. Adsorption equilibrium took about 60 minutes. Adsorption data show that the masimum amounts of adsorption of sodium silicate occurs at about pH 9.8. The adsorptivity was in the order of calcite > fluorite > scheelite. The amount of adsorption of sodium silicate increased with the increase in temperature of sodium silicate solutions. The amount of adsorption of sodium silicate decreases in the low concentration range of ferrous sulfate, while in the high concentration range of ferrous sulfate, the adsorption of sodium silicate increases.

Jan 1, 1986

By George Holderer

THE relation between man-hours of labor and production may be correlated for any industry, and already it has been widely used in piece-work studies. It is not in general use as yet for recording labor efficiency of an enterprise or an industry. An exception to this is the Cement Institute, which tabulates the man-hours used in each operation and FIG. 1.-LABOR PRODUCTIVITY IN COPPER MINING. thus gets the total man-hours per barrel of cement. The writer knows of one steel company that keeps a complete record of man-hours for every operation from mining the ore to finishing the product. No doubt many others find the information useful, and such a study could be of value to the mineral industries.

Jan 1, 1935

By Corale Brierley

The effect of hydrogen peroxide (H202) on growth and respiration of Thiobacillus thiooxidans and Thiobacillus ferrooxidans, organisms involved in acid leaching of copper sulfide minerals and uarnium oxides, was examined. Oxygen uptake and growth by T. thiooxidans were totally inhibited after contact with 0.82 mM H202. Complete inhibition of oxygen uptake by T. ferrooxidans occurred at 8.75 mM H202, and growth was inhibited after 6 hr exposure to 2.06 mM H202. Higher concentration of H202 can be used without detriment to thiobacilli if it is dissipated prior to reaching the oxidation pond or dump surface.

Jan 1, 1980

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York L. W. FRANCIS, Chairman. WILLARD S. MORSE, Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. P. A. MOSMAN; Treasurer. LOUIS D. HUNTOON. WILLIAM A. POMEROY Boston HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 1, 1915

By A. K. Burton

This paper reviews transportation trends in large base metal open-pit mines in recent years. Particular attention is paid to the unprecedented increases in the cost of oil and its effect on operating costs. Fuel conservation and measures to improve trucking efficiency are considered. The paper also discusses viable alternatives for reducing or eliminating the use of trucks. Various advantages and disadvantages of using conveyors to transport shot rock from the mine are reviewed. The paper concludes with some observations on current policies and trends primarily aimed at mitigating the high cost of energy.

Jan 1, 1983

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York L. W. FRANCIS, Chairman, WILLARD S. MORSE, Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. P. A. MOSMAN, Treasurer. LOUIS D. HUNTOON. WILLIAM A. POMEROY. Boston HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. ROBERT H. RICHARDS,. ALBERT SAUVEUR. Columbia F. A.. THOMSON, Chairman. GEORGE W. RODDEWIG, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. R. S. McCAFFERY, S. H. RICHARDSON.

Jan 12, 1914

Jan 1, 1930

The income of the Institute is derived from dues, subscriptions to MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd M.emoria1 Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization and at a minimum of expense.

Jan 1, 1932

Jan 1, 1887

By L. G. Laureau

This paper is presented to call the attention of steel-manufacturers to the need of further reform in the manner of casting and handling ingots. The problem of making the work usually performed in and around the casting-pit less dangerous to the men and less costly to the management is one which has occupied the minds

Jan 1, 1885

By F. S. McNicholas

UNTIL the fundamentals of the physical behavior of rocks are completely understood, progress in block caving must proceed upon a cut and try basis. Criteria of rock failure are many and varied. If a rock mass behaved as a homogeneous isotropic solid, the problem would be greatly simplified. In practice we are never dealing with isotropic or homogeneous rock but with one that has been acted upon by geologic processes and which has pre-existing planes of failure. Under these complex conditions we do not find agreement. Actually there is little agreement between elasticians and physicists as to manner of failure in an isotropic homogeneous solid, although much progress has been made in the study of rock failure in recent years.

Jan 11, 1950

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period Mar. 10, 1916 to Apr. 10, 1916: R. C. Blanchard, London, England. George H. Packard, Boston, Mass. F. Lynwood Garrison, Philadelphia, Pa. Harvey B. Small, Mangangue, Colombia, S. A. S. A. Horton, Altoona, Pa. H. De Witt Smith, Kennecott, Alaska. J. S. Lane, New York City. Richard Tarantous, Terlingua, Tex. Harry T. Mercer, Painesdale, Mich. S. A. Taylor, Pittsburgh, Pa. A. L. Blomfield, for many years in the employ of Bewick, Moreing & Co. as metallurgist, and for the last eight years mill superintendent of the Golden Cycle mill at Colorado Springs, has become associated with The Dorr. Company as consulting metallurgical engineer, with headquarters at Denver. He retains his connection with the Golden Cycle mill as general superintendent.

Jan 5, 1916

By John H. Smith

Because of increased pressure from federal and state regulatory agencies, most acid flows will require some sort of treatment prior to being discharged to receiving streams. In many industries, the volumes of liquors are large and their acid content varied. Development of a waste treatment process minimizing equipment cost and utilizing land efficiently is mandatory. Methods of acid neutralization with lime have been known for years, however, the volume and characteristics of the resultant precipitated solids can create a disposal problem. Also, when standard lime treatment is used, the settling characteristic of the precipitated solids is normally slow. In some instances, the necessity of added dissolved solids removal, such as iron, needing aeration, add to the problem of concentrating neutralized solids.

Jan 12, 1972

By D. M. Bondurant

Auger mining-extraction of coal with large diameter augers is proving profitable in recovering coal left after stripping has ceased to be economical. Its many advantages-low initial cost of equipment, low operating cost, low power demand, adaptability to selective mining, simplicity of operation, etc.-have excited the interest of some in the industry in its possibilities for underground operation.

Jan 5, 1951

By Milton Glicken

The airborne geophysicist is a busy man these days. In his plane he may have the airborne magnetometer, the airborne scintillation counter, and the airborne electromagnetic surveying system. Each of these is an independent tool, but all require additional auxiliary equipment for locating the aircraft in space: recording altimeters and Shoran or aerial cameras. Now there is still another piece of equipment, the airborne magnetic gradiometer, an accessory to the magnetometer. To understand its uses, consider the function of the magnetometer itself. Aside from detecting magnetic ore, the airborne magnetometer finds greatest use in spotting intrusions of igneous material. Where there is enough contrast in magnetic susceptibility of igneous rock and adjacent formations, it outlines the intrusion. Certain minerals also influence the magnetometer directly, but with the exception of magnetite and possibly one or two others, their effect is weak and can be detected only when there is sufficient ore and the magnetometer flight passes very close to it.

Nov 1, 1955