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By W. L. Austin

The advance made in recent times in this branch of metallurgy is indicated by the attention the subject is receiving from important American copper-producing companies. Reference to the files of publications devoted to the mining industry discloses that some 20 American companies are actively investigating the amenability of their ore, or other material, to leaching methods, and that plants of varying capacities up to 10,000 tons per day arc under construction or are projected. Several leaching works are in commercial operation. It has been frequently pointed out that no method of leaching is universally applicable, for the reason that each ore differs in some particular from apparently similar ore found elsewhere, and also because local conditions are rarely the same even where the ore closely approximates in character that being worked at some other point. For this reason the older companies are approaching the matter in a conservative manner, experimentally determining for themselves the salient features in each instance. In considering a leaching proposition three factors at once fix the attention: (1) disengaging the metal from mineralized forms in which it is found in nature; (2) recovering the metal in a commercial state after it has been dissolved; (3) the apparatus best adapted to carrying out the several operations. Bringing the Metal into Solution This feature.has been found to present no serious difficulties. Numerous solvents for copper are known, and it has been repeatedly demonstrated on a commercial scale that from 80 to 90 per cent. of the metal contained in an ore can be rapidly brought into solution. It is interesting to note, however, that all of the companies above referred to have selected sulphuric acid as the basis for a lixiviant. Where oxidized ore practically free from precious metals is treated simple leaching with

Jan 1, 1915

Jan 1, 1927

By Alexander L. Holley

Jan 1, 1879

Jan 1, 1915

Jan 1, 1917

By G. M. Swinkels, A. Vizsolyi, E. Peters

A process is described utilizing ferric chloride leaching followed by reduction of the cupric content to cuprous by cement copper, with CuCl obtained thereafter by crystallization. The residual liquor is cemented with sponge iron to produce cement copper and a copper free ferrous chloride solution. The latter is oxidized in an autoclave with oxygen to regenerate ferric chloride and to precipitate excess iron as a granular, filterable hematite. Cuprous chloride crystals are reduced to high purity metal with hydrogen, while sulphur reports almost quantitatively in residues in the elemental form. Pyrite and molybdenite are not leached. This paper describes the important variables in the process, as well as the deportment of minor elements as silver, gold, selenium, tellurium, bismuth, nickel, lead, zinc, magnesium, etc. An elegant method of isolating silver from CuCl crystals is described, as well as recovery of gold from residues by a chloride reagent The process is described as non-polluting and capable of producing refined copper, ore grade iron oxide, elemental sulphur, and yields of minor metals as good or better than obtainable by conventional smelting, without the use of solvent extraction or electrochemistry.

Jan 1, 1981

By R. S. Hutton

Jan 1, 1937

By H. W. Smith

This paper presents a review of developments to date in computer control practice, based in large part on Canadian experience. The basic problem examined is that of stabilizing control; matters considered are control strategies, hardware and software aspects of system implementation, reliability, human factors, and economic results.

Jan 1, 1976

By Waldemar Lindgren

Jan 1, 1905

By Burton H. Boyum

GREATER depth of exploration drill holes and increasing cost of drilling have been principal factors in reviving interest on the Marquette Iron Range in controlled directional drill-hole deflection. This deflection is obtained by the application of the Hall-Row wedging technique. Modifications were made in the technique and equipment in the effort to simplify and strengthen the procedure. The practice is similar in many respects to the oil well type of deflection with a whipstock.

Jan 1, 1947

By Erwin S. Sperry

The formation of cracks in metals is one of the most perplexing obstacles encountered during the process of rolling. When occurring in brass they may be due to several causes: 1. Shrinkage-cracks. These are caused by a rough or cracked mould which prevents the metal from shrinking uniformly and without rupture. It is consequently torn apart. In the majority of instances such cracks are visible to the naked eye, and often penetrate the metal to a considerable depth; in others they are nearly if not quite microscopic, but

Jan 1, 1899

By Russell A. Carter

Although significant phosphate mining activity has occurred in four western states-Idaho, Montana, Utah, and Wyoming-southeastern Idaho contains the largest, most easily mineable reserves, and mining has focused there. More than half of the western phosphate field's economic reserves are within a 32 x 96-km (20 x 60-mile) rectangle bounded by Montpelier, Idaho, on the south, Soda Springs on the west, and Grays Lake on the east. A large amount of this land lies within the boundaries of the Caribou National Forest.

Jan 1, 1978

By Waldemar Lindgren

CONTENTS. [ ] THE following pages are a resun16 of some of the conclusions reached during a study of the copper-deposits near Clifton The field-work was finished in 1902 and a complete report is now in the press. A preliminary description of the district was published in 1903, in Bulletin U. S. Geological Survey, No. 213. pp. 133-140

Jan 1, 1913

By Ralph Hayden

PAGE I. IntRoduction........239 II. Definition of Anaconda SLime....240 III. The Source of Slime......240 Remodeled Flow Sheet......240 Old Plow Sheet,.......242 IV. ConStitution of Slimes......243 Chemical........243 Physical.........243 V. The Slime Problem.......247 VI. THe Experimental Slime Plant....248 VII. Slime Thickeners. ETc .......249 Slime Ponds........249 Tanks.........249 Comparative Efficiency of Open and Baffle Tanks .260 Callow Tanks........252 Kuchs-Laist Centrifugal Separator....253 Garred Filter........256 Dorr Continuous Thickener.....256 VIII. Concentrators........257 Round Table........558 Peck Centrifugal Concentrator....259 Competitive Tests.......260 Twenty-Deck Round Table..... 260 Slime Feed Distributor......261 IX. ConcluSion.........262 I. Introduction. In the wet concentration of ores there is always a certain amount of very fine material with which to contend. and which invariably carries such quantities of value that the treatment of it is worth while. commercially. This fine material usually contains that portion of the ore which hinders the separation of the mineral values: namely. the colloidal material resulting from the decomposition of certain constituents of the ore. The object of this paper is to show what efforts have been made to solve the slime problem as it occurs in the concentrator of the Washoe

Jan 1, 1914

Jan 1, 1901

By H. A. J. Wilkens, H. B. C. Nitze

At the Atlanta meeting of the Institute in October,' 1895, some brief remarks were made by Mr. Wilkens on the above subject. It is the object of this paper to set forth the substance of these previous statements, embodying therewith additional information gained since that time, and a brief illustrated description of the method and means of the separation.* Lack of time will unfortunately not allow as complete a resume of the subject in all its phases, especially those relating to the scientific side of the question, as its novelty and importance would warrant, so that even this paper must be considered a preliminary one. It is hoped that at some future meeting of the Institute we may find an opportunity of presenting supplementary data of interest. The paradoxical title above used requires some explanation. The term " non-magnetic material " is applied to such substances as have heretofore been considered non-magnetic in the arts, more especially in the practice of ore-concentration. Scientifically, it has been shown by Faraday, Plucker, Wiedemann and other physicists that magnetism is an inherent property common to all substances, solid, liquid and gaseous, i.e., all suhstances are either attracted or repelled by the poles of a magnet, although ill the great majority of cases the manifestation of this

Jan 1, 1897

Uranium was the prima donna of 1978, and the exploration pace was fast and furious in traditional uranium producing areas such as the Powder River Basin, Grants mineral belt, San Juan Basin, and Uravan mineral belt. Adding fuel to the fire were several significant discoveries: The Date Creek Basin of western Arizona, the McDermitt caldera of northern Nevada, and Tallahassee Creek in Colorado's intermontane basin. Advances in solution mining haw resulted in deeper drilling on the Texas Coastal Plain, and the price of uranium has encouraged widespread exploration in frontier areas and non-sandstone environments.

Jan 5, 1979

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Jan 1, 1938

By Richard L. Coleman

Metallurgical testwork to develop a flowsheet is described, beginning with background information required right through to a final process flowsheet. Both laboratory and pilot plant testing are reviewed with emphasis on the former.

Jan 1, 1978

By Chester R. McKee, Robert W. Terhune, Merle E. Hanson

The relationships describing the enhancement of permeability by firing explosives in boreholes have been derived and combined to yield permeability enhancement as, [ ] or the case in which the stress decays asymptotically as a power law kc and nc represent permeability and fracture density at the edge of the pulverized region near the cavity wall, f is a geometric attenuation factor, m is the dissipation due to real material effects, ko is the original permeability and rd is the scaled radius. This relationship has been compared with available measurements from the American nuclear shot "Hardhat", the French nuclear events in Hoggar granite and the chemical explosive shot in coal near Kemmerer, Wyoming. Significant correlation between this theory and the experimental measurement is observed. A comparison between single and multiple detonations shows that permeability enhancement falls off steeply near the shot; however enhancement can be considerable midway between two shots spaced 10 cavity radii apart. The degree to which enhancement, can be significant depends on material properties and fracture density. Porosity distribution from the explosive 1s the dominate parameter in permeability enhancement. Existing theories of permeability enhancement have also been reviewed.

Jan 1, 1976