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By M. Earl Volin, M. Adnan Goksel

The hydro thermal agglomerating process described (U.S. Pat. No. 3,235,371, 1966)* is different from the cotzventional high-temperature processes. Green pellets or briquettes made with mixtures of moist iron-ore concen- trates and burned or hydrated lime fines are hardened in an azttoclave at 198°C and under steam pressure for 112 to 5 hr, with or without previous drying. Under the neutral conditiotzs, oxidation of magnetite does not occur as in the conventional processes. The resulting azzlomerates-- are hard and resistant to abrasion and weathering, and they do not disintegrate in the Under test. The equipment required for the process is not complicated, and favorable operating costs are projected because of the low temperamre and efficient heat recuperation. A low capital investment makes the process attractive even when the annual pellet production is below a million tons.

Jan 1, 1970

By Nelson Severinghaus

THIS Rock Chapel plant of Consolidated Quarries Corporation (Fig. 1) is three miles northeast of Lithonia, DeKalb County, Georgia. It was opened about eight years ago for crushed stone aggregate. This paper reviews a number of experiments that have been tried in drilling and blasting, and gives the practice in use today. It also present, several theories on the action of explosives in this type of blasting. [ ] The rock worked is a bare dome of granite gneiss about 3000 ft. in diameter, rising 150 ft. above the surrounding ground (Fig. 2). It is uniform in composition and quality, without seams, and extends downward to unknown depth below the quarry floor. A water well drilled 600 ft. remained in the same rock. The principal difficulty encountered in blasting is an easy split, which tends to break clown the rock in large blocks.

Jan 1, 1938

By S. W. Zanolli

The history of labor relations in the coal industry of the United States is a study of its collective bargaining. This study of collective bargaining is largely the history of the United Mine Workers of America and its contractual relations with the various coal mining employers who have produced this country's coal over the years under a free enterprise system. There have been other unions in the picture from time to time and some coal miners have mined coal without representation by any union. Even today some 25% of the nation's coal is produced outside of the collective bargaining relationship with the UMWA. However, more than 100,000 coal mine wage employees - well over 75% of the total in the industry - are covered by labor agreements negotiated for them by the UMWA. Practically all of these work in bituminous mines.

Jan 12, 1972

By Walter E. Lewis, Robert L. Marovelli

Underground support has a long history as evidenced by Agricola's general description in Dc Re Metallica:1 "The timbering of these openings is done as follows: stulls are set at intervals into hitches in the hanging and footwall, and upon them smooth poles are laid continuously; and that they may be able to bear the weight, the stulls are generally a foot and a half thick. After the ore has been taken out and the mining of the vein is being done elsewhere, the rock then broken, especially if it cannot be taken away without great difficulty, is thrown into these openings among the timbers, and the carriers of the ore are saved toil, and the owners save half the expense. This, then, generally speaking, is the method by which everything related to the timbering of shafts, tunnels, and drifts is carried out."

Jan 1, 1971

By A. Thies, Wm. B. Phillips

1. Introductory Remarks.—The Haile Gold Mine is in Lancaster county, South Carolina, 3 1/2 miles east of Kershaw station on the Charleston, Cincinnati and Chicago Railway. It was first opened about, the year 1832, and since that time has passed through various fortunes. Many different operations have been practiced here for extracting the gold : panning, grinding in Chilian mills or arrastras, stamping, the Designolle process, dry-crushing, and finally the Thies process of barrel-chlorination, which has now been in successful use for 2 1/2 years, and by which 36,000 tons of ore have been treated profitably. The Thies process is in brief the treatment of dead-roasted auriferous concentrates (pyrite, sometimes also chalcopyrite, as at the Phœnix mine, Cabarrus Co., N. C.) with nascent chlorine, without ' artificial pressure or exhaust, in lead-lined iron cylinders; the throw-

Jan 1, 1891

By John V. Beall

Given: One large, but dated open-pit copper mine and processing plants, down about one third in production capacity in decade because of declining ore grade. Solve for: Restoration of former peak capacity without further losses during period of reconstruction. That is the problem that Kennecott's Utah Cop- per Division began solving in 1963. Most of the work went to a task force of engineers, several of whom were plucked out of line jobs and assigned to the so-called "Expansion Project" for the duration. There was no doubt from the beginning that effective cooperation between Expansion Project engineers and operators was critical to success, and personnel was chosen accordingly. This foresight paid off. The Expansion Project is all but complete, and the Utah Copper Division is returning to its rated capacity of 300,000 tons per year of copper metal.

Jan 6, 1967

By Nelson Severinghaus

The Rock Chapel plant of Consolidated Quarries Corporation (Fig. 1) is three miles northeast of Lithonia, DeKalb County, Georgia. It was opened about eight years ago for crushed stone aggregate. This paper reviews a number of experiments that have been tried in drilling and blasting, and gives the practice in use today. It also presents several theories on the action of explosives in this type of blasting. The rock worked is a bare dome of granite gneiss about 3000 ft. in diameter, rising 150 ft. above the surrounding ground (Fig. 2). It is uniform in composition and quality, without seams, and extends downward to unknown depth below the quarry floor. A water well drilled 600 ft. remained in the same rock. The principal difficulty encountered in blasting is an easy split, which tends to break down the rock in large blocks.

Jan 1, 1938

By Nelson Severinghaus

The Rock Chapel plant of Consolidated Quarries Corporation (Fig. 1) is three miles northeast of Lithonia, DeKalb County, Georgia. It was opened about eight years ago for crushed stone aggregate. This paper reviews a number of experiments that have been tried in drilling and blasting, and gives the practice in use today. It also presents several theories on the action of explosives in this type of blasting. The rock worked is a bare dome of granite gneiss about 3000 ft. in diameter, rising 150 ft. above the surrounding ground (Fig. 2). It is uniform in composition and quality, without seams, and extends downward to unknown depth below the quarry floor. A water well drilled 600 ft. remained in the same rock. The principal difficulty encountered in blasting is an easy split, which tends to break down the rock in large blocks.

Jan 1, 1938

Weston Portable Electrodynamometer The Weston Electrical Instrument Co. of Newark, N. J., believes that problems hitherto considered impossible of solution in the designing of portable electrodynamometers have been solved in its new models. The voltmeter, Model 341, is an instrument' of precision adapted to use on alterating- or direct-current circuits, guaranteed to an accuracy of 0.25 per cent. full-scale value either on direct or alternating-current circuits of any frequency to 133 cycles per second and commercial frequencies even as high as 500 cycles per second with very slight error. The polyphase electrodynamometer, Model 329, is accurate to 0.5 per cent. under the same conditions.; Double ranges are furnished in all instruments of this model. All current ranges can be used for 100 per cent. overload indefinitely without introducing error in Models 310 and 329.

Jan 12, 1915

By S. A. Braley

Drainage of acid mine water into surface streams of coal mining areas is one of the most serious problems of stream pollution, since there is no known method that completely prevents its forming and no economically feasible treatment after it has formed. The mine acid problem differs from other pollution hazards because acid production does not end with cessation of mining but actually becomes more evident when pumping is stopped. The acid problem in the Pennsylvania, Ohio, West Virginia, and Kentucky bituminous coal areas of the U. S. began with the first operation in 1761, and the volume of acid discharge today is largely the cumulative result of years of mining. Provided they lie above the drainage area, the oldest mines, now long abandoned, are almost without exception producing acid in the same manner as those now operating or recently abandoned.

Mar 1, 1956

Capable of processing 3500 tpd of uranium ore, the United Nuclear-Homestake Partners' mill in Grants, N. M., differs considerably from the nearby mills of Anaconda and Kerr-McGee in at least two major aspects: it leaches uranium ore with an alkaline solution of Na2C03 and NaHC03 instead of sulfuric acid; and it recovers yellowcake directly by precipitation from the pregnant alkaline leach solution, without any need of ion exchange or solvent extraction circuits. A first look at the flowsheet shows that this mill has two separate grinding and leaching circuits. Reason for the double circuitry: the mill treats, on a toll basis, uranium ores for Anaconda as well as for the partnership, and it must also treat ores coming from mines separately owned by Homestake Mining Corp. and from mines owned by United Nuclear Corp.

Jan 8, 1974

By W. P. Blake

THIS furnace is designed especially for the oxidation of sulphur or arsenic in pyritic ores, but may be used for all oxidizing or desulphurizing operations, and for calcining, roasting and chloridizing ores, or for drying ores in large quantities preparatory to treatment by magnetic separators or otherwise. It is of the tabular, revolving type, with automatic feed and delivery, and is a modification of the Cornish calcining furnace, designed by Brunton, from which it differs, however, not only in construction, but in two or more radical features, for which novelty is claimed and patents have been applied for. The principal of these novelties are: 1. A series of concentric terraced floors, one above another. 2. The introduction of superheated air upon the charge without contact with the fuel. In the furnace which I have had in operation for more than a

Jan 1, 1893

By R. L. Tobie, E. K. Staley

Because of high production demands at San Manuel mine (approximately 40,000 tpd) and the relatively narrow grade range of the orebody, no attempt is made by the company to mine selectively. The caving sequence is laid out to meet the production demands, and proceeds in a manner to induce the least amount of weight on extraction openings. Once an area is undercut, draw control procedures are applied uniformly until the area has been mined to depletion. The orebody, located 50 miles northeast of Tucsoil, Ariz., is a low-grade deposit of chalcopyrite disseminated throughout a structurally weak, highly fractured, strongly altered granitic host rock over- lain by several hundred feet of relatively competent andesitic conglomerate. When undercut, the granite ore caves readily into fragments which usually pass through the grizzly without either excessive breaking or an undue amount of secondary blasting.

Jan 6, 1967

By John V. Beall

New York was bathed in pale winter sunshine and, surprisingly, coatless weather. The time was the AIME Centennial and 100th Annual Meeting. From advance peeks into the fabulous schedule of events we were well aware that the Centennial Committee, New York Host Section and AIME staff' had pulled out all the stops, laying on the best of everything, but the weather gimmick was the frosting on the cake. The Formal Greetings Session on the first morning, Joe Alford confided, was the greatest AIME experience of his life. Without doubt the honor bestowed on AIME by the greetings and felicitations of the presidents of the world's leading professional engineering societies was the greatest moment in AIME history-save one. That one exception was in 1928, when 1920 AIME President Herbert C. Hoover was elected President of the United States.

Jan 1, 1971

By G. Stuart Jenkins

CONDITIONS at the properties of the Consolidated Coal Co. had reached a point where improvements were almost impractical. The mines, sunk years ago, had shafts and entries so small as to preclude the use of large mine cars. A radical change was necessary in the type of mining and also in the type of mine to accommodate such haulage units. After due consideration, the company decided to enter the field of trackless mining, utilizing belt conveyors and chain-flight conveyors, the belt conveyors to take the long haul, and the chain-flight conveyors to be used for gathering. It was decided not to sink a shaft, but to drive a slope on an inclination of 17 1/2°, which the company believes to be about the limit on which coal can be carried on a belt without rolling back unduly.

Jan 1, 1939

By R. Adair, W. R. Hudspeth, W. T. McDaniel

A NEW method for concentrating the flake mica either from present washing plant tailings or from new feed has been developed. In this paper, flake mica refers to that which occurs in weathered granites, alaskites, pegmatites, and schists in a form too fine to be considered sheet mica. It ranges in size from 1 in. or more down to 200-mesh or finer and occurs with kaolin, quartz, and partially kaolinized feldspar. Scrap mica, a term often used indiscriminately to describe everything other than sheet mica, will be used to denote the waste product from sheet mica mines and fabricating plants. Both flake and scrap mica are used in the mica grinding plants to produce wet-ground or dry-ground mica, although some flake mica recovered from clay mining operations is fine enough to be marketed without grinding.

Jan 3, 1951

By T. Okubo

Gold is generally recovered from silver anode slime by electrolysis in the final step of the copper anode slime treatment. In the present investigation, rapid and direct hydrometallurgical separation and recovery of gold in the early step of the process is studied. Gold is recovered just after the elimination of copper and selenium from copper anode slime. The studied process consists of: (a) oxidizing roasting for selenium elimination, (b) sulfuric acid leaching of the calcine for copper removal, reduction of gold in the liquor by the use of proper reductant such as hydrogen peroxide (production of gold powder), (el nitric acid treatment of gold powder for further purification and (f) melting and casting of gold. Laboratory and miniplant testwork showed that the extraction ratio of gold by chlorine leaching was 99 % up and four nine gold ingot could be recovered without electrolyses.

Jan 1, 1984

By S. R. Smith, W. M. Voorhis, J. D. Young

The Tennessee Valley Authority (TVA) has conducted investigations to identify the major causes of coal pile inventory adjustments. This paper describes past and current attempts to improve inventory survey accuracy and reduce costly inventory adjustments. The unique interaction between accountants and engineers is also reviewed. Data and results of a recent field test wing downward-looking radar developed by Ohio State University are presented. These show great promise in determining coal pile depth and density, thus improving inventory accuracy. This electromagnetic remote sensing technique, if successful, would provide an optimum technical and economic method of surveying all 12 TVA stockpiles without costly borehole drilling or disrupting stockout and reclaim activity. The effect of changing coal quality to meet environmental standards has made accurate coal pile density measurement more important than ever in reducing the costs of electric power generation from coal.

Jan 1, 1984

OCHRE is a semimineral composed by Nature of earth and a tincture of yellow caused by a fumosity of lead ore. By itself it is a material without any [38] metal, although when it is used in smelting it helps to melt the harsh and sour ores of metals. I do not know that it has any other use, except to painters. Bole is also a red viscous earth which has a very astringent and drying nature. It has no very apparent smell or taste, and I think that the cause of its redness lies in the fumosities of iron ore, for it is a companion to this and is found in its mines. It is an efficacious medicine against any poison and in this capacity has an action like terra sigillata* or perhaps better. In

Jan 1, 1942

By Thomas M. Drown

The following description of an attempt to separate bituminous coal from its slaty and mineral admixtures without the aid of jigging, was suggested by the successful use of dense solutions (such as the double iodide of mercury and potassium and cadmium borotungstate) in the separation of the mineral components of igneous rocks.* In the case of coal it is essential that we have a solution of a specific gravity greater than the coal, and less than the mineral or slate associated with it. Further, in order that such a solution should be practically admissible, it must be cheap and readily obtainable. Calcium chloride fulfils all these conditions, although it is not intended to be affirmed, in the absence of actual trial, that its use on a large scale would be economically successful. The records of experiments on several samples of bituminous coal

Jan 1, 1885