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By A. K. Isaac

The effectiveness of coalface powered support depends upon its structural nature and the manner of application of the hydraulic system. A critical and largely unresolved feature of the system is the optimum setting pressure level at which a support should operate in its geological environment. This paper provides an argument for a generalised approach to the issue of setting pressure level quoting case study data for a high output British longwall installation.

Jan 1, 1984

By J. F. Myers, F. M. Lewis

This second progress report of grinding presents comments regarding ball consumption and data pertaining to the hydroscillator, which is closed circuited with the tricone mill. A study and postulate of how balls function is presented. The paper summarizes cost reduction obtained by the method of "grinding for the tail race" rather than for "mesh tons."

Jan 11, 1950

By E. P. Pfleider, C. A. Dufresne

The problem of mooing open-pit ores over large vertical distances is increasing in importance because of the immense deposits being mined. Gravity fall of ore through transfer raises to central haulage points underground has advantages for certain open-pit operations, and this method is being seriously considered for the Carol Project now underway in Canada.

Jan 6, 1961

By Lap-yan Chan

Chan and Goodman (1983) presented a procedure for simulating joint traces and identifying key blocks on an excavation. This paper defines six measures of support requirements that characterize the number and dimensions of key blocks, taking into account the frictional properties of joints and actions of support systems. When correlated with case histories, these measures of support requirements can help in choosing an optimal design for shallow excavations in discontinuous hard rocks.

Jan 1, 1984

By H. E. Mauck

The many factors that control bumping must be carefully studied for each coal seam where bumps occur, and specifications known to exclude bumping should be incorporated in the mining plans. This calls for complete knowledge of the seam's characteristics and its adjacent strata, and in many instances these characteristics are not revealed until the seam is actually mined. Pressure and shock bumps, the two general types, occur jointly and separately. In this discussion no differentiation will be made. Whether pressure or shock, they are treated as bumps, and both must be eliminated.

Jan 9, 1958

By Charles L. Elliot

Data for mining applications of geophysical activity in the Free World in 1963 has been collected by the Committee for Geophysical Activity of the Society of Exploration Geophysicists. This information has been made available to the AIME and is published here in abstract form with the kind permission of the SEG. The data is based or1 244 responses (51%) to the questionnaires circulated among 475 worldwide organizations engaged in mining geophysical operations and or research. It is believed that the data is a realistic appraisal of actual world geophysical activity.

Jan 8, 1964

By A. Stumpf, Y. Berube

An experimental apparatus for studying the aqueous oxidation of sulfide minerals is presented. The oxidation kinetics for molybdenite in solutions of caustic soda and dissolved oxygen are discussed; results of leaching experiments on chalcopyrite concentrates are given. Preliminary results on the transfer of oxygen into water are also discussed.

Jan 1, 1974

By ME ME

IT just so happens that we do our best thinking while painting wood- work and last Saturday while finishing up the screens (the bugs come late where we live) the paint very nearly ran out. By adding turpentine, it just stretched. It was pretty thin for the job though, which made us think that that is just about what the situation is going to be in the mining industry if something isn't done to increase the number of enrollments in engineering curricula. Engineers are going to be spread too thin for the job at hand.

Jan 8, 1951

By Duk-Won Park, Syd S. Peng

For an adequate design of the shortwall face support, it is necessary to understand fully the support- roof interaction. A series of studies has been carried out at a shortwall panel to develop the methods of monitoring support resistance and determining load density of the chocks. Various aspects of applications, for improvement of chock design and understanding of roof conditions, are discussed.

Jan 1, 1981

By Stewart K. Griffiths

A general method-of-lines numerical approach for modeling gas driven fractures has been developed and tested. The numerical solutions agree very well with known similarity solutions for laminar and turbulent flow. Acceptable accuracy is obtained with a very few numerical grid points and with modest execution times. The model has also been checked against the results of several field tests, in which air was used to drive axisymmetric fractures into permeable tunnel-bed tuff.

Jan 1, 1984

By John B. Pearse

THE works heretofore used in carrying out the Bessemer process have been constructed substantially as follows : The whole works or plant has been divided into three parts. 1. The division in which the metals for conversion are melted. 2. The division in which the metals are converted into steel and cast into ingots, or the converting department. 3. The engine and boiler department which supplies the hydraulic power required to move the machinery, and which furnishes the blast used for converting the crude metal into steel.

Jan 1, 1876

By George F. Sowers

THE geophysical methods of exploration employed so extensively in mining and petroleum investigations are now being used in civil engineering. Requirements differ from those of mineral ex- ploration and therefore modified techniques have been developed. The civil engineer is primarily interested in the uppermost soil and rock strata. In highway engineering the materials affecting design and construction may be found within 15 or 20 ft of ground surface, and data on soils and rocks is seldom needed for more than a depth of 100 ft even for the heaviest structures.

Jan 1, 1954

By William J. Bronkala

Magnetic Separation is a proven means of effectively obtaining purification and/or concentration of mineral products. In addition, magnetic separators are widely used for tramp iron removal in the protection of mineral processing machinery such as crushers, conveyors, mixers, etc. This paper summarizes the various types of magnetic separators available and outlines their basic selection and usage. Current magnetic separator costing is provided for general guidance and estimating.

Jan 1, 1978

By H. W. Imholz

This report covers most of the counties in North Central Texas in which oil is being produced in commercial quantities. The exceptions are McCulloch and Runnels, which were omitted because the production is small and the detailed information necessary for a report is not available to the writer. Complete information was not available regarding the number of wells drilled in this district during the year. The writer wishes to thank Mr. T. F. Petty, of the Humble Oil and Refining Co., Wichita Falls, Texas, for information used in compiling Table 2.

Jan 1, 1937

By Dale K. Fields

With today's technological advances in mineral processing equipment, there is an increasing demand for accurate system control. This can only come about through representative sampling. The purpose of this paper is to guide in the selection of sampling equipment and outline design parameters for the cutters used in dry and wet sampling without adding redundant mathematical probability formulas. Special attention will also be given to the equipment used in conjunction with samplers and sampling system, such as feeders, crushers, chutes, launders, and controls.

Jan 10, 1979

By Theron Wasson

During 1936 the state of Michigan produced 11,868,573 bbl. This is approximately 4,000,000 bbl. less than produced in 1935. The principle reason for the decrease in production over the previous year was the rapid decline of the Crystal field, which reached its peak in October 1935. The old producing area—Mt. Pleasant, Porter, Yost-Clark— accounted for over 7,000,000 bbl. during 1936. Crystal produced a total of 2,400,000. Outstanding among the old fields were Vernon and

Jan 1, 1937

By O. Skiredj, J. F. Elliott

It has been necessary to collate the available data on the solubility of graphite in Fe-Si-Mn alloys for a study of slag-metal equilibria in ferromanganese production. That study will be reported later; the collation is reported here. The carbon content of graphite-saturated liquid iron above 1153ºC by Chipman and co-workers1 is: %C= 1.34 + 2.54 x 10~3t(°C) [l] For graphite-saturated manganese above 1322ºC it is: %C = 2.68 + 3.52 x 1CT3 t(°C) [2]

Jan 1, 1963

By D. E. Munson, P. R. Dawson

An empirical model is developed that predicts accurately the transient response of salt creep to incremental and decremental changes in stress and temperature. Even though the model is empirical, it is derived from a firm theoretical framework for the micromechanical deformation processes of both steady-state and transient creep. In the model, the transient creep functions modify the steady-state creep behavior, which in turn is based upon creep mechanisms and the def ormation-mechanism map. The model is applied successfully to experimental stress-drop results obtained for salt.

Jan 1, 1982

By W. S. Hungerford

As several papers on the subject of mining in soft ore-bodies have recently appeared in the Transactions and in the Engineering and Mining Journal, the following brief account of the method introduced by the writer at Low Moor, Va., may be of interest. It is in some respects similar to the system at Longdale, Va., referred to in Mr. Rothwell's paper, though differing in many of its details. That system has been employed by the Longdale Iron Company for many years, and to that company the writer is indebted for many

Jan 1, 1889

By R. J. Block, G. H. Kehl

IN order to investigate the possibility of a spontaneous low-temperature transformation, resistivity measurements were made on a sample of eutectoid beryllium- copper. A cast specimen of 5.965 pct Be, 94.035 pct Cu was homogenized at 650°C for 22 hr, furnace cooled to 550°C, and held for 2 hr to allow the 0 - a ß-a+? reaction to proceed. In an attempt to refine the ß grain size, the specimen was then reheated to 620°C, held

Jan 1, 1960