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By S. G. Lasky

Editorial writers and convention speakers are inclined to lean hard on certain perennial topics which need a better degree of definition. One of those topics is mineral self-sufficiency. Everyone interested in it ought to adhere to the definitions and absorb the background data set forth here by Mr. Lasky which nails down the subject to talkable dimensions once and for all! Mineral self-sufficiency is a flexible concept-one which changes with both economic and political vicissitudes.

Jan 8, 1961

By H. M. Howe, W. E. C. Eustis

THE processes which form the Subject of this paper have been experimented on in the laboratory of W. E. C. Eustis, but have not passed beyond the experimental stage. The first is the invention of Mr. J. L. Thomson, of Capelton, Quebec, Canada, the others have been invented by the writers. THOMSON'S PROCESS FOR THE EXTRACTION OF NICKEL This consists essentially in first rendering the nickel magnetic, and then separating it from the materials. with which it is mechanically

Jan 1, 1882

By Pete Turcic, Wade E. Cooper

Many factors influence radon-222 influx and radon-daughter concentrations in underground uranium mines. A brief review of some of these factors is presented. Current radon-222 and radon-daughter control principles and practices for U.S. underground uranium mine atmospheres are discussed and a brief review of the applicability of other possible control methods such as rock sealants, radon-222 removal, and radon-daughter removal is given.

Jan 1, 1982

By T. A. Read, H. M. Otte

THEORETICAL analysis by Wechsler, Lieberman and Read of the crystallography of martensite formation has shown that the requirement for the existence of a macroscopically undistorted plane between austenite and martensite permits a calculation of the indices of the habit plane of the marten-

Jan 1, 1958

By E. A. Sondreal, F. I. Honea

This paper summarizes coal and ash properties and pilot-plant results for 14 key lignite seams in the Gulf Province, as well as discusses operating problems encountered by the four Texas power plants burning Gulf Province lignite. Some consideration is given to the design of future power plants.

Jan 1, 1982

By Gerald Sherman

Asbestos ore is hard, well intersected by free fissuring but not completely enough to avoid heavy secondary blasting, and is a more valuable ore than usual for caving. These factors have resulted in deviations from standard caving practice in details but not in principles.

Jan 4, 1950

By William P. Dyrenforth

The principle of electrostatic separation is discussed and elaborated on by dividing into the three main mechanisms of electrification as applied to separation of solid substances, i.e., (1) contact electrification, (2) electrification by conductive induction, (3) electrification by ion bombardment. Types of equipment used for electrostatic processing are described and the effects of humidity mentioned. Processing of iron ore, titanium minerals, rare earths and cassiterite is discussed and some existing plants are described.

Jan 1, 1978

By D. W. Gentry, H. E. Sherer

Determining the age at which to replace a specific piece of mining equipment, and choice of the best possible replacement, is a problem common to nearly all mining operations. This paper examines the data required for intelligent equipment replacement decisions and discusses how to predict future repair cost from historic data, determine the total cost of various replacement alternatives, and evaluate the different replacement alternatives. Various operations research and computer methods were used to develop this easily-used, practical equipment replacement method.

Jan 1, 1984

By W. W. Anderson

A formula for quantitative efficiency is proposed, in which the efficiency value is a function of the improperly distributed material at the gravity of separation effected by the cleaning equipment. The misplaced material is expressed as a percentage of the total material discharged from the equipment. Numerous examples are given, demonstrating application of the formula to various types of separation, including multiple-product separations.

Jan 2, 1950

By Roger Thunvik, Carol Braester

Excavation of cavities below the ground water level induces water influx from the surrounding aquifer. An estimate of the rates of flow prior to excavation operations may be of valuable information for the mining engineer. The present paper deals with water influx into cavities of the tunnel type, e.g., mine galleries, tunnels, etc. The solution of the flow problem was obtained by a numerical finite difference method. The results are presented in dimensionless form as a function of the parameters characterizing the location of the cavity in the aquifer.

Jan 1, 1981

By D. J. Christie, W. C. Hellyer

Three autogenous grinding flowsheets were considered as follows: 1) Primary autogenous grinding of a -8-in, primary crusher discharge to produce a product suitable for second stage pebble milling, or a flotation feed product in a single stage of grinding. 2) Intermediate autogenous grinding in which +4-in. rock media is screened from the primary crusher discharge and employed as grinding media to grind a tertiary crusher product to flotation feed size in a single stage.

Jan 8, 1972

The Howe Memorial Lecture, in memory of Henry Marion Howe, Past President of the Institute, was authorized in April, 1923, as an annual address to be delivered by invitation under the auspices of the Institute by an individual of recognized and out- standing attainment in the science and practice of iron and steel metallurgy or metallography, chosen by the Board of Directors upon recommendation of the Iron and Steel Division. The follow- ing were the Howe lectures and lecturers for the years indicated: 1924 What is Steel? By Albert Sauveur. 1926 Austenite and Austenitic Steels. By John A. Mathews.

Jan 1, 1932

By W. C. Krumbein

GEOLOGICAL problems are approached from a geometrical (space relations) viewpoint, a kinematical (time sequence) viewpoint, or a dynamical viewpoint. The first two require sound training in conventional geology and in field methods. The third approach requires a solid foundation of chemistry, physics, and mathematics. Modern training for geologists should include close integration of basic sciences with geological principles.

Jan 1, 1941

By Eckley B. Coxe

IN making surveys in the anthracite coal regions of Pennsylvania, the ordinary engineer's chain (50 or 100 feet long) is generally used, both above and below ground. Sometimes, where it is difficult to chain, as, for instance, across a chasm, a wire is stretched from one station to the other, the distance is marked on the wire and its length is then measured with the ordinary chain. Having had occasion lately to make some surveys where it was necessary to determine with great accuracy the position of the land or property line, not

Jan 1, 1874

By D. B. Reger

DAVID B. REGER.-T Want to 'add that since this paper was prepared a well is now being; drilled it the location recommended do the last page. It was not, however, done at my instance; it was done at the instance of Dr. White, the State- Geologist of West Virginia, who has been trying for several years to induce the large oil and gas companies to make a test of some of these, deep sands in West Virginia and a well is now just being started in Wood County, right at this immediate

Jan 4, 1917

By Joseph L. Mehaffey

A variety of chemicals offered by Armak were evaluated as dewatering aids for aqueous slurries of silica sand, sparsand and feldspar; an established commercial dewatering aid was used as a control. A number of Armak’s potential dewatering aids yielded lower moisture retention values than did the commercial product on all of the mineral samples. In addition to the chemical dewatering evaluations, some of the mechanisms involved in the removal of water from these mineral samples were examined.

Jan 1, 1984

By George W. Mansfield

My plan in this paper is, first, to prove three general points, and then to take up the specific applications of the electric motor to nining work. The three poinb are: 1. The electric system is the simplest method known for transmitting and distributing any amount of energy from one locality to another, irrespective of the intervening distance. 2. The electric system with its applications is not in its infancy.

Jan 1, 1888

By Colin G. Wilson

This paper considers the heavy liquid laboratory tests used to determine the amenability of a potential ore to the heavy media process. The results of the laboratory testing are correlated to actual plant performance and establish design parameters for the heavy media process. These parameters are used in the development of the metallurgical flow sheet and in the sizing of equipment in the metallurgical plant design.

Jan 1, 1978

By Walter L. Rice

It is a pleasure to report that the light metals industries are running well ahead of the growth schedule projected by the President's Materials Policy Commission. In the compilation of this survey on the five-year growth of our light metals industries, some gratifying facts come to light. By 1956, for instance, light metals consumption had increased more than 20 pct beyond Paley report expectations-a growth not anticipated by the study until the year 1960.

Jan 9, 1959

By Edwin A. Sperry

At the request of some of my engineering acquaintances, to whom the results became known, I submit the following description of the survey made by me for the underground tunnel-connection between the Riverside and Home coal-shafts, at Leavenworth, Kansas. The State law requires an escape-shaft; and as neither of the shafts had one, the two companies decided to make this connection in order to comply with the law and still escape the great expense of sinking

Jan 1, 1895