Search Documents

Jan 1, 1947

Jan 1, 1929

[ ]

Jan 1, 1938

Jan 1, 1947

By William P. Blake

A recent paper by Prof. George P. Merrill, Curator of the Department of Geology of the U. S. National Museum, Wash-

Jan 1, 1897

Jan 1, 1923

By E. J. Freeh, W. E. Horst, R. C. Kellner

A technique useful in the important area of process-model building is described. The procedure is illustrated in the development of a mathematical model to describe the unsteady-state process of batch ball-mill grinding. The influence of certain assumptions relative to model structure are quantitatively evaluated and reviewed.

Jan 1, 1969

By James B. Fletcher

Leaching of the block caved mine from 1941 through 1970 is described, and the improvements made are listed. Detailed is the increased knowledge of leaching gained through this operation, including methods used in forecasting production, prediction of the economical end point, rate of recovery, and ultimate recovery.

Jan 1, 1972

By Young C. Kim, William C. Cassun

A proper economic analysis of pit slope design must reflect the trade-off between the benefits and the increased risk of slope failure inherent in steeper slope angles. This paper describes the results of a case study in which a newly developed probabilistic economic analysis procedure was applied to the selection of a pit slope design at a large porphyry copper mine in the southwestern U.S. The paper also demonstrates the availability of the required data such as the probability of failure schedule and cost of failure models, under "real-life" conditions.

Jan 1, 1978

By Amos Bowman

In the last two years I have had an opportunity to study the conditions of gold-mining in the far northwest of the Pacific coast —in Cariboo district, British Columbia. That country joins Alaska

Jan 1, 1887

By Michael J. Abrams

The large amount of data available from Landsat has made digital processing necessary to extract and display that subset of data relevant to the problem being considered. Computer image processing techniques developed and used at the Jet Propulsion Laboratory can be divided into four categories: rectification, cosmetics, display, and analysis. These techniques have been applied to various geologic problems, including mineral exploration, lithologic mapping, hydrology, and tectonics.

Jan 1, 1977

By W. Arthur White

Underclay squeeze is the plastic flowing of underclay below coal pillars into mined-out entries and rooms. Squeezes may be caused either by wet mine conditions where the moisture is taken up by the clay-making it more plastic-or by the presence of certain clay minerals, such as mont-morillonite, which are plastic when there is enough natural moisture. Under either condition, sufficient stress will cause the underclay to flow. Squeezes may fill an entry or room within several hours, or it may be several months before movement stops. Squeeze areas commonly cover hundreds or thousands of square yards.

Oct 1, 1956

By O. E. Michaelis

The metal used at the Befors Works in gun-munufacture is unforged open-hearth steel, cast without blow-holes. It has from time to time been asserted that it is impossible to pro

Jan 1, 1888

By W. C. Peters

Geologists take the role of mine geologist when they apply their science to the design and operation of a specific minerals project. In doing so, they use the entire spectrum of procedures in economic geology and engineering geology to deal with a specific system of orebodies and associated environment. The objectives are established by stages in the life cycle of a mining operation as it goes from a prospect to a development project and on to a mine. This paper summarizes the elements of a mining geologist's role, with examples highlighted from the preceding papers.

Jan 1, 1984

By J. E. Lawver, G. L. Samsel

The success of many mineral dressing processes, including froth flotation and electrical concentration, depends largely on knowledge of physical and chemical structures of the mineral surfaces involved. As a general rule solids have surface layers, usually invisible by optical tests, that differ from the substratum. To the mineral engineer, therefore, a knowledge of the surface structures of minerals is of paramount importance. During the past decade one of the most powerful tools in the study of froth flotation mechanisms has been the use of radioactive tracers, but this technique usually cannot give definite information regarding the chemical changes that may or may not have occurred at the surface.

Jan 5, 1959

By J. D. Bateman

At Giant Yellowknife, where high grade gold-bearing orebodies are highly irregular in shape, geology has been applied extensively to the mining of ore. The classical functions of the mine geologist in the fields of exploration and mine development have been extended to guide ore extraction, ensuring "clean" mining and effectively reducing waste dilution.

Jan 12, 1951

By H. Conrad, K. Janowski, G. Stone

The available data on the dynamics of plastic flow of sapphire indicate that the deformation rate in the temperature range .from 900° to 1700°C can be expressed either as A number of investigators1-10 have established that sapphire deforms plastically above 900°C, the most common mode of deformation being slip on the basal plane in the [1120] direction. Under certain conditions and at temperatures above 1500°C, slip

Jan 1, 1965

By William Kent

During the discussions at the Philadelphia meeting in February last;) several speakers expressed their doubts of the general accuracy of chemical analyses of steel made by "iron works chemists," and especially of determinations of manganese. Since the meeting, the discussion of the " practical value of chemical analyses" has been continued at some length in 'the columns of the Iron Age.

Jan 1, 1882