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Jan 1, 1965

UNIVERSITY OF ALABAMA University, Ala Mining and Metallurgical Society G T Bator UNIVERSITY OF ALASKA College, Alaska Mining Society Earl H Beistline-

Jan 1, 1952

By H. T. Heard

An engineer's wife is more concerned with stores than stopes, and she answers the question-can you get rich overseas?

Jan 7, 1951

By Charles M. Cooley

A NOTED Prospector Passes-Stories of the grizzled old prospector that discovered what turned out to be a famous and highly profitable mine, only to die in poverty through the shenanigans of "the Interests," are legion. It is pleasant, therefore, to be able to report that the discoverer of one of Canada's most famous mines was more fortunate.

Jan 7, 1953

In the mile-high city of Denver. Colo., the mining industry's political adjunct, The American Mining Congress, held its annual meeting, September 27-30. The Honorable Maurice H. Stans, in what became the keynote address of the meeting, spoke of a "common interest in a basic reality of 1970, a reality involving ecology, energy, raw materials and natural resources.”

Jan 1, 1970

By Jack White

This paper gives details of the results of careful testing carried out on two types of ball mills, conical trunnion overflow and cylindrical grate discharge, on identical ore. The object of the test work was to determine which ball mill was the most economical to install for future extensions to the Mufulira concentrator.

Jan 1, 1950

By C. K. Leith

The question as to what grades of ore it pays to conserve for the future, and the valuation of low-grade reserves, are becoming immediate and definite as applied to the individual ore deposits, and seems to call for some sort of quantitative answer.

Jan 1, 1915

By Persifor Frazer

From the easternmost point reached by the Ural excursion of the VIIth International Geological Congress (the city of Tschéliabinsk, a little more than 30' of longitude east of St.

Jan 1, 1899

By Emanuel Trotz

As the long-felt need of a reliable and easily-managed pyrometer has now been fully supplied, by the latest form of Professor Wiborgh's pyrometer, an account of this instrument will, per-

Jan 1, 1893

By Philip S. Mathews

THE tremendous stimulus given to the mining industry by the gold and silver policy of the present administration has found the capital market for mines ill prepared to afford practical means of financing. Particularly has this been true of the host of abandoned high-cost producers and prospects which increased gold and silver prices have made potentially profitable. In a comparatively short time, experience has demonstrated abundantly that valuable properties have frequently failed to secure capital, while questionable properties have drawn to themselves and their promoters more of the public moneys than their prospects justify. Singularly enough the fault is usually attributable to faulty financing. Discussion and study of this problem are vital to the industry.

Jan 1, 1936

By R. T. DeHoff

A theoretical development is presented which reformulates Fick's first law for diffusion in the solid state. The diffusion flux of component i in a multi-component system, Ji, is related to its local concentration, ci, and local jump frequency, ri : where a is a geometric factor and d is the jump distance. The product, ciri , is defined as the local concentration of atomic jumps for component i. The analog to Fick's second law is also derived. A solution to this equation is presented, which permits the experimental determination of the variation of atom jump frequency with composition in multicomponent systems. HISTORICALLY, the description of diffusion in the solid state has been presumed to be best approached as an application of more general diffusion laws, known as the phenomenological equations. These equations relate the flux, Ji, of the various components, expressed in atoms, grams, or volume, to the driving force involved, expressed as either a compositional or chemical potential gradient, sumption that the flux is simply proportional to the driving force is the foundation of this approach. The phenomenological equations take the form: where the concentration gradients are assumed to be the driving force, and: if the chemical potential gradient is taken as the driving force. The coefficients Dij in Eq. [1.] are the "diffusion coefficients"; the elements of the corresponding matrix in Eq. [2], the Mij, are called the "mobilities". Eqs. [I] and [2] may be considered to be definitions of these phenomenological coefficients. A formidable body of literature has been generated about these equations; this literature dates back to their original formulation for the simplest case of binary diffusion in a fluid, by Adolf Fick, in 1855.' This description has been shown to be self-consistent. However, the "constants of proportionality", the Dij or ,Mij, are not constant: they vary with composition in all but the simplest systems. Even in the case of tracer diffusion, wherein it can be shown that the diffusion coefficient is constant, the mobility, which is considered in irreversible thermodynamics to be the more physically meaningful quantity, varies with the concentration of the tracer involved.' In more complex systems, it is necessary to evaluate the entire matrix of phenomenological coefficients, as a function of composition, in order to describe diffusion locally. Further, in order to determine this matrix experimentally, it is necessary to produce diffusion couples that have different sequences of compositions; the matrix may be evaluated only at points where these "composition paths" cross.* Finally, and perhaps most

Jan 1, 1969

EXECUTIVE COMMITTEES OF LOCAL SECTIONS Arizona E. P. MATHEWSON, Chairman W. V. DECAMP, First Vice-chairman F. W. MACLENNAN, Second Vice-chairman E. D. GARDNER, Secretary-Treasurer, U. S. Bureau Of Mines, Tucson, Ariz. MICHAEL CURLEY J. P. HODGSON HENRY F.1 ASTER CLYDE E. WEED Boston Meets first Monday each winter month GEORGE A. PACKARD, Chairman FRANKLIN B. RICHARDS, Vice-chairman F. LEROY FOSTER, Secretary-Treasurer Rooms 8-219 Mass. Inst. of Tech., Cambridge, Mass. G. W. METCALFE D. H. MCLAUGHLIN

Jan 1, 1932

By E. Ryba, D. J. Michel

SAMPLES of REZn2 (RE = rare earth) intermetallic compounds prepared by a variety of techniques have been shown to exhibit an extensively twinned micro-structure.1-4 We have recently conducted compression tests at room temperature on specimens of HoZn2 prepared by a powder metallurgy technique.' The microstructures of specimens before and after testing are shown in Fig. 1. The "before" specimen, Fig. l(a), shows the basic twin structure of this material. Fig. l(b) shows the microstructure of the "after" specimen just below the fracture surface and reveals considerable cross-twinning as well as additional

Jan 1, 1970

By M. P. Nackowski

Geological engineering expanded its role and significance during 1966 in the areas of construction, raw materials exploration and inventory, water supply and pollution, mechanical properties of earth material and regional environmental planning. Efforts varied immensely in scope and magnitude, in simplicity, difficulty and importance. Observations, measurements, and analysis encompassed both simple and sophisticated procedures. CONSTRUCTION Activities in construction ranged from preliminary to detailed evaluations of sites, development of preventative measures and designing corrective measures following construction failures. Most investigations concerned dam sites, highway locations and slope stability, building sites, tunnels and underground storage facilities.

Jan 2, 1967

By C. Carlson, W. Muir

The oxygen demand of the complex lead-zinc-iron feed at the Cyprus Anvil concentrator was determined dependent on the cyanide ion concentration of the pulp. By redistribution of the cyanide added to the grinding circuit in direct proportion to the amount of surface area created, a more activated flotation feed is obtained. Monitoring the oxygen demand of the flotation feed and grinding mill discharges has proved useful in diagnosing metallurgical problems in day-to-day operation.

Jan 1, 1976

By D. W. Schmidt, J. W. Shuster

Use of electric-wheel-driven haulage trucks at Chino dates back to 1963, and in today's fleet of 38 units, 17 trucks are electric-wheel- type powered with 700 hp diesel engines. Output of these engines is not adequate to exploit fully the 1200 hp potential of the two electric- wheel-drive motors, and, as a result, Chino has been testing larger prime power sources. An earlier test involved the use and evaluation of 1000 hp gas turbine engine in a conventional Model M-100 Unit Rig haulage truck (see [ ], May 1967, pp. 57-60). Now Chino has tested a trolley-diesel application in the same 100-ton capacity vehicle, and has shown that trolley power on electric-wheel-drive trucks can improve productivity rates from 18-36% on adverse grades, depending, of course, upon haul road profiles.

Jan 3, 1968

By Stuart M. Buck

THE term "splint" seems to have been adopted to describe the fracture of the hard bituminous coals of West Virginia. It is not a scientific name,, but rather a trade term, and does not indicate a correspondence with English splint. At present it is a popular word, and is very loosely applied to coals of various qualities, in the desire to improve their sale. The Kanawha splint is distinguished by its hardness, dull lustre, coarse fibrous structure, its purity, and especially its resistance to atmospheric influence. It kindles very readily, burns with a bright flame, but does not cake, so that a lump when half consumed, may be broken by a slight blow in its plane of cleavage, though 'it will resist a' strong blow in any other direction. I have seen pieces that have been exposed to frost and sun

Jan 1, 1882

By Sir John Cadman

IN THE changed circumstances which now confront the world, an international open-door policy is the only way to keep pace with the world's demand for oil. You may rest assured that as far as the British Empire is concerned, American capital for the develop-ment of oil resources is welcome, and little obstruction will be found in the way to permit the use of foreign capital in the group of countries which constitute the British Empire. In the war days we worked in close cooperation and harmony, but in disbandment of the Petroleum War Service Committee, when the war ended, I feel that it left its task unfinished. In the wake of war there appeared a ghost of war-time conditions in the form of belief that Great Britain was straining to corner the petroleum resources of the world. I am certain that if the war-service committee had continued its work in the period of reconstruction the real story would be known and this sinister ghost would have long since vanished before the truth.

Jan 2, 1922

By Stuart M. Buck

The term "splint" seems to have been adopted to describe the fracture of the hard bituminous coals of West Virginia. It is not a scientific name, but rather a trade term, and does not indicate a correspondence with English splint. At present it is a popular word, and is very loosely applied to coals of various qualities, in the desire & improve their sale. The Kanawha splint is distinguished by its hardness, dull lustre, coarse fibrous structure, its purity, and especially its resistance to atmospheric influence. It kindles very readily, burns with a bright flame, but does not cake, so that a lump when half consumed, may be broken by a slight blow in its plane of cleavage, though it will resist a strong blow in any other direction. I have seen pieces that have been exposed to frost and sun

Jan 1, 1882