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By Evert Hoek

SYNOPSIS It can be shown that the properties of intact rock are relatively unimportant in rock slope stability and that failures are controlled by structural discontinuities such as bedding planes, joints and faults in the rock mass. The frequency, orientation and inclination of these discontinuities as well as their strength characteristics are important factors to be considered in any rock slope analysis and their influence will be demonstrated by means of a number of practical examples. Methods for determining the mechanical properties of discontinuities will be reviewed and the interpretation of the strength test results for use in stability computations will be discussed.

Jan 1, 1971

By J. A. Herbst, J. L. Sepulveda, J. D. Miller

Lead cake, a zinc smelter flue dust residue, consists primarily of lead sulfate. Characteristic properties of lead cake were determined in order to aid the understanding of reaction mechanisms involved in bismuth removal from lead cake by sulfuric acid digestion. Sp gr (specific gravity) measurements, surface area measurements, and photomicrographs revealed that the particles of lead cake are quite porous and seem to consist of an agglomeration of submicron grains (0.4 pm) fused together in a manner similar to cement clinker. Analysis of experimental rate data, which was independent of particle size, indicates that the dissolution reaction involves two distinct, rate limiting steps. The initial stage of reaction appears to be limited mainly by intergranular diffusion of the reactant, hydrogen ion, while the latter stage of reaction appears to be controlled by diffusion of soluble reaction products through the reaction product layer of the individual grains.

Jan 1, 1979

Jan 1, 1908

By Alfred H. Bell, George V. Cohee

In 1939 Illinois produced 94,302,000 bbl. of oil—almost three times the amount of oil produced at the peak in 1908, when development in the southeastern Illinois field was at its height (Fig. I). It represents nearly a fourfold increase over the 24,075,000 bbl. produced in 1938 (Table 6). This rapid increase in oil production in Illinois is largely due to development in the Salem and Louden fields (Table I). During 1939 daily production for the state increased from 135,000 to 332,572 bbl. A notable increase in production for 1940 is expected as a result of the drilling of the Devonian limestone in the Salem and Centralia fields,

Jan 1, 1940

By Wayne L. Dowdey

With proud humility and keen anticipation, I accepted the office of President of the Institute one year ago, and it is with a great deal of pride in you-our membership that I make this report. You are the reason for a productive and prosperous year for AIME. Superior, good or satisfactory results were experienced in 1978 from almost everything we did as a leading engineering technical society. I recognize and pay tribute to the WAAIME organization. Their work is vital to our efforts, and their programs have proven effective. WAAIME can depend upon our continuing support.

Jan 6, 1979

By Alfred H. Bell, George V. Cohee

In 1939 Illinois produced 94,302,000 bbl. of oil—almost three times the amount of oil produced at the peak in 1908, when development in the southeastern Illinois field was at its height (Fig. I). It represents nearly a fourfold increase over the 24,075,000 bbl. produced in 1938 (Table 6). This rapid increase in oil production in Illinois is largely due to development in the Salem and Louden fields (Table I). During 1939 daily production for the state increased from 135,000 to 332,572 bbl. A notable increase in production for 1940 is expected as a result of the drilling of the Devonian limestone in the Salem and Centralia fields,

Jan 1, 1940

By R. B. Sudderth, C. R. Merigold

Greater, emphasis is being placed on recovering nickel from laterite ores by ammonia leaching techniques. New methods are required for lower cost, non-polluting techniques to separate more efficiently the metals of interest. Liquid ion exchange techniques meet these requirements with the added advantage of producing salable electrowon nickel cathodes at the plantsite. A complete solvent extraction- electrowinning process is described, including preliminary engineering and cost data for a typical plant producing 50 million pounds of nickel per year.

Jan 1, 1973

By E. H. Lovitt, A. C. Skerl

After nine years of continuous operation it is a good idea to take stock of the geological concepts that guide the working of a mine. This is a welcome opportunity to discuss the Lovitt gold mine, which has been a challenge in both the geological and operational fields. The occurrence belongs to the extensive group of epithermal gold-silver deposits once worked so vigorously in the western states, Hungary, and New Zealand and still producing in Central America and the Philippines. These deposits are characterized by a relatively shallow vertical range up to 2000 ft, and often much less, and by bonanza orebodies of even more limited range. The area in which they occur is frequently widespread, so that exploration must be directed along and across the strike of known favorable structures in search of repetitions.

Jan 9, 1958

By Henry Howe

§1. FOUR ASPECTS OF FLOW in the plastic deformation of steel by overstrain, such as punching, wire-drawing, tensile rupture, etc., are: (1) The inter-granular, i.e., the relative movements of the several grains, each as a whole; (2) the intra-granular, i.e., the relative movements of the masses of ferrite or cementite and pearlite within those grains; (3) the intra-pearlitic, i.e., the relative movements of the pearlitic ferrite and cementite; and (4) the crystal unit slipping, i.e., the travel of the minute units past each other, along the slipping planes, giving rise to the slip bands of Ewing and Rosenhain. It may be objected justly that (2), (3), and (4) are in a sense "intra-granular," and that (4) is in a sense "intra-pearlitic." Hence clearness may be gained at times by calling these "Movements of the 2d, 3d, and 4th orders" respectively.

Jan 4, 1914

By Zavis M. Zavodni, Carl D. Broadbent

During the past 15 years, rock mass structural properties have become acknowledged as the focal point for rock slope design. Re- search into the methods for measuring and incorporating structure into the design effort has taken many directions and has produced a variety of useful techniques. Among the findings at Kennecott has been the realization that structure-controlled instability can be categorized as regressive or progressive depending on the relative geometries of slope and structure and on the strength characteristics of the structures. It was further identified that a failure condition can initiate as regressive and in time become progressive should external stimuli increase or structure characteristics be altered due to extensive displacements. The transition point has been shown to be a useful indicator of the expectable collapse time. This paper defines three fundamental failure types as dictated by structure and offers discussion on the practical value of such a classification to slope design and failure control. Several prominent examples of failures typifying the categories of structure- controlled instability are discussed. An application of f allure prediction based on the regressive-to-progressive transition point is described.

Jan 1, 1983

By George Evans

DURING the past ten or twelve years, the average reader of newspaper and magazine articles has been led to believe that enormous deposits of high-grade coal exist in the northland and that these can be mined for practically nothing. But much of the reputed glitter and attractiveness of Alaskan coals disappears when viewed at close range. Many areas of coal-bearing rocks are widely distributed geographically from Cape Lisburne, on Bering Sea, to Admiralty Island south of Juneau. Bituminous coal is found at Cape Lisburne, on the Bering Sea, at Five Finger Rapids on the upper Yukon, and at Herendeen Bay and Chignik Bay; lignite is found on the Kobuck River, along the Yukon River from points near the mouth to Tonakat, near Rampart, at Dawson, on the east shore of Cook Inlet, and in the Tanana Valley, 50 mi. south of Nenana. The Susitna and Matanuska Valleys contain coal ranging from lignite to anthracite, and in the Bering Lake district, there are coals ranging from semi-bituminous to anthracite. No effort will be made to describe all of these fields, but the writer wile confine himself to the four principal fields, namely, the Nenana field, in. the interior of Alaska, tributary to the Fairbanks district; the Matanuska, field, in the Matanuska Valley; the Kachemak Bay field on the east shore of Cook Inlet; and the Bering River field, east of the mouth of Copper River.

Jan 2, 1921

By E. W. Greig

This paper is an account of exploration for bauxite in the Amazon Basin, Brazil, and particularly of the discovery, exploration and development of the Trombetas deposits by Alcan. A general report of the Trombetas Project has already been published in E/MJ(Anon. 1975) to which the reader is referred for details on ownership, infrastructure and construction as well as the proposal for mining and treating the bauxite. A regional account of bauxite in and around the Guyana Shield and the northern part of the Brazilian Shield is included to help explain the geology of the Trombetas deposits and their relation to other bauxites in northern South America. It is suggested that all these deposits formed during Tertiary time under similar geologic conditions.

Jan 1, 1979

GENTLEMEN : It is my privilege to transmit herewith the reports for the calendar year 1932 of your Treasurer and the Chairmen of the following Standing Committees: Finance, Admissions, Membership, Papers and Publications, Library, and Mining and Metallurgy. To these reports you are referred for additional details of the year's activities. Finances.-Continuation of depressed conditions in the mining industry (in common with other industries) caused the income of the Institute to decline from $168,274 in 1931 to $138,331. However, economies were effected so as to reduce expenditures from $171,198 to $135,977. As a consequence the net result of the operations for the year was a-surplus of income amounting to $2,354 compared with a deficit of $2,924 in 1931. This gratifying result is accounted for in large measure by the foresight of the Finance Committee in anticipating a substantial decline in income and preparing the budget accordingly. Incidentally, the tentative budget for 1933 has been balanced at $125,000.

Jan 1, 1932

Jan 1, 1902

International Trade in Nonmetallic Minerals. BY J W FURNESS AND E W PEHRSON (Man &. Met, Sept, 432 2500 words) International trade in nonmetalic minerals (exclusive of fuels) is dominated largely by fertilizer raw materials such as phosphate rock, potash, nitrates, sulphur and pyrites and the miscellaneous group of minerals including asbestos, mica, graphite, fluorspar and china clay Cost of trans¬portation deters any substantial movement of the building materials which usually occur widely in nature and are thus available near consuming centers at relatively low cost This paper, which presents a summary for 1932 of the world production, consumption and principal trade relations of asbestos, china clay, fluorspar, graphite, gypsum, mica, phosphate rock and potash illustrated by world charts, is based on an original study of 15 nonmetallic minerals conducted by the U S Bureau of Mines Practical and Legal Aspects of Mme Financing See METAL MINING Economic Significance of High-grade Concentrates See MILLING AND CONCENTRATION

Jan 1, 1937

By Waldemar Lindgren

I. Character of the Deposits, 226: Principal Features, 226 (Form, 227; Posi tion, 227 ; Constituent Minerals, 227 ; Exceptions, 228) ; Literature, 228 ; Geo graphic Distribution, 230 ; (California, 230 ; Idaho, 231 ; Arizona, 233 ; British Columbia, 233; Northwest Territory, 234 ; Mexico, 234; Other Countries, 235). 11. Origin oF the Deposits, 236 : Contact-Metamorphism, 236; Caw of Contact Metamorphism, 237 ; Similar Deposits of Different Origin, 240; Genetic Classifi cation, 240 ; Relation of Pegmatite- Veins to Ore-Deposits, 242. I.—Character of the Deposits. 1. Principal Features. In many schemes of classification and description the term contact-deposit has been somewhat loosely applied to all accumu-

Jan 1, 1902

By L. Adler

A fairly complex analysis is required to select or evaluate a piece of excavating and bulk handling equipment for its performance. At present, there is little agreement as to what points should be considered, and even less on what procedure to follow. This paper provides both of these in a consistent and direct form. The analysis applies to all types and sizes of equipment. The importance of the equipment characteristics, job activities, and work conditions are stressed. Separate analytical stems are established in a flow chart for these. They are combined using suitability tests in: problem statement; natural conditions; suitability guidelines; appropriate equipment types; operational activities; encumbered space; geometric design; equipment sizing; failure and limits; performance and consumption; public policy checks; and costs and profitability. Public policy and economics receive emphasis towards the end. The procedure is iterative, containing distinct feedback loops. Specifying the steps and sequence provides a necessary structure which has long been overdue.

Jan 1, 1985

The opening session of the A. I. M. E. was held at the King Edward Hotel, Toronto, on Tuesday, July 25th. Dr. W. G. Miller, on behalf of the Local Committee, opened the proceedings. [ ] President John Hays Hammond, who occupied the chair, introduced Alderman Graham, Chairman of the Reception Committee, and representative of the city, in the absence of His Worship the Mayor. A brief address of welcome was delivered by the Alderman and responded to by President Hammond. The President then requested Dr. James Douglas to present to the honoured Secretary of the Institute, Dr. Rossiter W. Raymond, an oil portrait.

Jan 1, 1907

By G. W. R. Kuzyk, John D. Smith

Tantalum Mining Corporation of Canada Limited has been mining tantalum ore from the Bernic Lake pegmatite dyke since 1968. The shallow nature of the dyke and relatively high strengths of the various rock types led to the choice of a room and pillar mining method. Rock mechanic studies have indicated that the original pillar dimensions of 50 feet x 50 feet are conservative for existing rooms. Therefore, a plan to reduce the size of pillars using rock mechanics instrumentation to monitor the resulting stress on pillar remnants and stope backs was devised. The paper describes the test work done on the rock types within the pegmatite dyke. The use of Irad stress cells and extensometers in monitoring the stress in pillars is described. The actual results of the program to date are presented.

Jan 1, 1983

By R. W. Raymond

The death of Professor Blake removes the oldest of American economic geologists and mining engineers, and deprives this Institute of one of its earliest and most illustrious members. To many of us it brings a personal loss also, the loss of a friend. William Phipps Blake was born June 21, 1826, in New York City. His father, Elihu Blake, was a surgeon-dentist of eminence, a direct descendant of William -Blake, who settled in the Massachusetts Bay Colony about 1630. He was prs pared for college at private schools in New York, and entered the Sheffield School of Yale, where he was graduated as Ph.B. in the chemical course, class of 1852, the first graduating-class of the institution. In the same year he became chemist and mineralogist of the New Jersey Zinc Co., and chemist of chemical works at Baltimore, Md. In 1853, he started the Department of Mineralogy of the World's Fair at New York City. In 1854, 1855 and 1856, he was mineralogist and geologist of the United States Pacific Railroad Surveys of Willianlson, Pope, and Whipple, and for the War Department at

Jan 1, 1911