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By Bertrand Robinson

Epitomized, there have been no innovations recently in crushing, but in grinding the trend has been towards larger units under more automatic control with an increased use of autogenous grinding. Crushing Portability of primary crushers to "follow the face" reduces material handling costs. The top size of crusher feed still establishes the size of the crusher; the feed opening should be 1 1/2 times the size of the largest feed. The maximum size of crusher product is 1 ½ times the open scale setting of a jaw or gyratory crusher. Practice dictates use of scalping screens ahead of any type of crusher when the feed contains 25% or more of product size. If required capacity is under 600-700 tph economics favor a double toggle crusher or an impactor. For larger capacities the gyratory crusher is favored.

Jan 1, 1970

By C. C. Harris

The Gaudin-Meloyl equation for the size distribution of fragments resulting from single fracture is where y is the mass fraction of material smaller than size x, and x, and r are parameters to be determined from the experimental data. In physical terms, r is associated with the number of active flaws in a particle of characteristic dimension xo . The special attribute of this equation is its emphasis on the coarse size region of a distribution. There are various procedures2-5 for obtaining the parameters in Eq. 1, but a simple graphical method is awaited. This situation contrasts sharply with that in the cases of the familiar Gates-Gaudin-Schuhmann and Rosin-Rammler equations.6 The purpose of this note is to present a method based on a procedure7 which has been successful in several other applications.8-13

Jan 1, 1967

By W. E. Horst

During the past few years of operation at Kings Mountain, N. C., full-scale flotation has generally yielded poorer metallurgical results than those obtained in the laboratory or pilot plant. After 2 min in each size of Denver flotation machine in the spodumene rougher circuit, pilot recovery (41.7 pct) was almost three times that of the plant (13.6 pet) and about twice that of the laboratory (21.0 pet). Pilot and commercial plant data are based on continuous operation, and laboratory results on batch testing of rougher performance. The ore is a pegmatite containing spodumene, feldspar, quartz, mica, and amphibolite. Data were accumulated to evaluate the scale-up relationships between laboratory, pilot plant, and plant flotation cells. Flotation rate constants and dimensional analysis were used to define the relationship existing between flotation behavior and scale of operation.

Jan 11, 1958

NEW MEMBERS. The following list comprises the names of those persons who became members during the month of June, 1913: Members. ANGERER, VICTOR, Vice-Prest. and Genl. Mgr., Wm. Wharton, Jr. &, Co., Inc., 25th St. and Washington Ave., Philadelphia, Pa. BULLOCK, ALLYN, Min. Engr., Hazleton, Pa. CUNNINGHAM, NOEL Met. Engr. Hollinger Gold Mines Ltd., Timmins, Ont Canada ESTABROOK, EDWARD L., Supt. of Colliery 426 Center St., Ashland, PA. GATES A. O. Instructor Purdue Univ. La Fayette Ind. 1 LUDLUM, ALBERT C., Prest., New York Engrg. Co., ,2 Rector St., New York, N. Y. MILLER, HERBERT F., Met. Engr P. O. Box 142, Verona, Pa. MORTON, ELMER T., Min. Engr Clifton, Ariz. MURFIT, RICHARD H.. Fdv. Asst Hess Steel Castings Co., Bridgeton, N.J. QUAYLE, THEODORE W., Chief Sampler, Metcalf Mines, Arizona Copper Co., Metcalf, Ariz.

Jan 7, 1913

By Michael B. Kahle, Fred J. Scheaffer

Production scheduling, along with production planning, provides projections of future mining progress and time requirements for the development and extraction of a resource. These schedules and plans are used by management as a means of attaining the following objectives (1) maintaining or maximizing expected profit, (2) determining future investment in mining, (3) optimizing return on investment, (4) evaluating alternative Investments, and (5) conserving and developing owned resources. The first four goals are generally concerned with mining costs, both capital and operating requirements, and as such, play an important role in production planning. However, this chapter is concerned with the fifth management objective of resource development in order to conserve and perpetuate the corporate entity. The following discussion is based on the premise that detailed economic evaluations and market surveys have been performed and analyzed and that the results indi¬cate a viable project.

Jan 1, 1979

By C. Feng, C. Elbaum

AN investigation of the fracture plane of titanium, containing 0.5 wt pct to 1 wt pct 0, was recently carried out by fracturing large-grain specimens in a tensile jig at room and liquid air temperature. The experiments were carried out on strip specimens 3 to 5 mm wide, 2 mm thick and about 100 mm long. The specimens consisted of several grains, each occupying the entire cross section of the strip and extending over a length varying from 5 to 20 mm. These specimens were prepared by a method described elsewhere.' The identification of the fracture plane was possible in twelve of approximately thirty crystals investigated. In some cases severe local distortion took place near the fracture and prevented identification of the fracture plane. On, at least, three occasions the fracture propagated in a helicoidal

Jan 1, 1959

By David R. Mitchell, H. E. Oehler, Henry Emmett Gross

The production of fluorspar is one of the smaller nonmetallic industries in the United States with a capital investment—about $10,000,000. Shipments from United States mines1 in 1936 totaled 176,231 short tons valued at $3,111,268, an average price of $17.65 per ton. The United States produces about 40 per cent of the world's fluorspar, of which about 90 per cent comes from the Illinois and Kentucky deposits along the Ohio River.2 Further detailed information on the fluorspar industry in the United States is given by Hatmaker and Davis.28 The concentration of the coarser sizes presents relatively little difficulty, good recoveries being obtained with jigs and tables. However, sizes smaller than about 10 mesh cannot be successfully treated by ordinary gravity separation methods and so have been accumulating as

Jan 1, 1939

By Henry Emmett Gross, David R. Mitchell, H. E. Oehler

The production of fluorspar is one of the smaller nonmetallic industries in the United States with a capital investment—about $10,000,000. Shipments from United States mines1 in 1936 totaled 176,231 short tons valued at $3,111,268, an average price of $17.65 per ton. The United States produces about 40 per cent of the world's fluorspar, of which about 90 per cent comes from the Illinois and Kentucky deposits along the Ohio River.2 Further detailed information on the fluorspar industry in the United States is given by Hatmaker and Davis.28 The concentration of the coarser sizes presents relatively little difficulty, good recoveries being obtained with jigs and tables. However, sizes smaller than about 10 mesh cannot be successfully treated by ordinary gravity separation methods and so have been accumulating as

Jan 1, 1939

By O. P. Arora, J. B. Darby, Paul A. Beck

LAVES and Wallbaum' reported that the phases occurring at the compositions TiFe, TiRu, and TiOs, which are stable over a wide range of temperatures and are separated from neighboring phases by wide two phase fields, have a CsC1-type ordered structure. For TiRu and TiOs, this was recently confirmed by C. B. Jordan.2 Recent results of Greenfield and Beck3 show that solid solutions with ruthenium of the body-centered-cubic elements vanadium and tantalum (and presumably also of colum-bium) in group Va of the periodic table undergo CsC1-type ordering. Although detailed phase diagrams for these systems are not yet available, it would appear that these ordered structures are separated from the neighboring body-centered-cubic solid solutions by relatively narrow two phase fields.

Jan 1, 1957

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 A. T. Yu

Over the last 80 years the conveyor belt has advanced from the troughed rubber belt to those with standard steel cable cores and those which can navigate curves or climb steep inclines. Now the latest generation of belt conveyors can claim hitherto unheard of capacities of 20,000 tph and single flight lengths well exceeding 16,000 feet. The stranded steel cable core belt is principally responsible for the spectacular improvement in load carrying ability of belt conveyors. The allowable working tension of these belts ranges from 2,500 lb per in. of belt width for 1/4 in. diam cable to 4,000 lb per in, for 3/8 in. diam cable. These ratings far exceed the 240 lb per in. per ply for rayon or nylon construction, and 30 lb per in. per ply for a lowcost cotton fabric.

Jan 1, 1970

By Douglas Baker

Zinc concentrates assaying approximately 54% zinc and 30% sulfur are roasted in a suspension type roaster to yield a zinc oxide calcine assaying about 65% zinc and 0.40% sulfur. This calcine is the feed material to the sulfuric acid leaching section of an Electrolytic Zinc Plant. The SO2 gases resulting from the elimination of sulfur from the concentrates are passed through a waste heat boiler for the generation of high pressure steam, cleaned by a baghouse, and delivered to the humidifying tower of a sulfuric acid plant system. The gases are then treated in a mist precipitator for final fume removal and then converted to sulfur trioxide in a three pass contact system using vanadium pentoxide catalyst for the manufacture of sulfuric acid. Waste heat steam is used to power the steam turbine which drives the acid plant blower.

Jan 1, 1970

By I. Iwasaki, R. H. Heerema

The presence of calcium and magnesium ions in iron ore pulps that are upgraded by selective desliming can result in indiscriminate flocculation of both iron oxide and siliceous gangue slimes. The removal of these alkaline earth cations in pulp solutions by chemical precipitation was ineffective as a means of deflocculation of quartz. It was shown by using various techniques (electron micrographs, abstraction, and streaming potential measurements, and cationic flotation tests) that heterocoagulation between the precipitates [Mg(OH)2, hydroxyapatite, and CaCO3] and quartz particles was the reason behind that observation. In addition, the precipitates adversely affected the recovery of quartz by cationic flotation, due to slime coating, a case of heterocoagulation. Magnesium hydroxide produced a uniform layer of coating across the quartz surface, while hydroxyapatite and calcite produced discrete, localized deposits dotting the surface.

Jan 1, 1981

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons. ) Position in sales department is open for a mining engineer with experience in mine ventilation and possessing some knowledge of fan design; one competent to lay out ventilating systems to meet various conditions. No. 2. A large company manufacturing mining machinery has an opening in one of its Western agencies for a young mechanical engineer who has had some experience in designing along general machine shop lines, and who is familiar with cost systems. No. 3. A large university desires to secure a prominent metallurgist for a vacant professorship in metallurgy. No. 4. Opening at a mine in New Jersey for a technical graduate to begin work as chairman on the surveying squad. Salary $50 per month to start. No. 5.

Jan 11, 1913

By George Schore

Radiation grafting of ion exchange structures contains ion exchange groups but may consist of neutral groups. High energy grafting of monomers on to polymers has-been known since 1950 (1.2); manufacture on an industrial level was-begun in 1970.(3) Proper choice of substrate and monomer will produce various ion exchange membranes with differing physico and chemical properties. Grafting a selected monomer to the proper polymer will provide selective ion exchange with assured chemical protection of the substrate. Ion exchange systems utilizing radiation grafted structures to polymers have been fabricated to "capture" gold from drag-out and rinse water and silver from cyanide rinse water. Other ion exchange systems can feasibly be produced to remove other precious metals. Rotating Cathode Technology is used to recover the metals from their concentrated eluating solutions as pure metal foil.

Jan 1, 1984

By L. D. Mullins, H. B. Bradley

Numerous articles have appeared in the literature citing the application of the potentiometric analyzer to cycling operations. Specific information obtainable by a potentiometric analysis, as noted by various investigators, includes: 1. Pattern sweep efficiency for various injection and production rate programs. 2. Injected fluid breakthrough time at production wells. 3. Optimum production and injection rates. 4. Prediction of injection and/or production well locations. 5. History of advance of the in-jected-produced fluid interface. 6. Ultimate life of the reservoir. 7. Ultimate reservoir production. This note describes a procedure for predicting pressure distribution in a gas-condensate reservoir by using the potentiometric analyzer to obtain potential distribution data on an analog model of the reservoir and then applying Muskat's' equations. The method relates the volumetric weighted average datum pressure to the mean potential in the model.

Jan 1, 1958

By E. C. Reed

Ninety wells were completed in Nebraska during 1941, of which 42 were producers. One of them was the discovery well of a new field. All of the production to date is in Richardson County. At the close of the year 14 wells were drilling and three more were shut down for orders, hoping for future development of production. Most of the drilling activity was in Richardson County, which had 68 operations; 10 wells were drilled in Nemaha County, 5 drilled or drilling in Gage County, 3 each in Otoe and Furnas Counties, 2 each in Cass, Harlan, Johnson and Sarpy Counties, and 10 wells were completed or drilling over the remainder of the state. The most important development of the year was the discovery in October of the Barada field, sec. 36, T. 3 N., R. 16 E.,

Jan 1, 1942

By E. C. Reed

Ninety wells were completed in Nebraska during 1941, of which 42 were producers. One of them was the discovery well of a new field. All of the production to date is in Richardson County. At the close of the year 14 wells were drilling and three more were shut down for orders, hoping for future development of production. Most of the drilling activity was in Richardson County, which had 68 operations; 10 wells were drilled in Nemaha County, 5 drilled or drilling in Gage County, 3 each in Otoe and Furnas Counties, 2 each in Cass, Harlan, Johnson and Sarpy Counties, and 10 wells were completed or drilling over the remainder of the state. The most important development of the year was the discovery in October of the Barada field, sec. 36, T. 3 N., R. 16 E.,

Jan 1, 1942

By D. L. Abata

This paper discusses recent technology dealing with the use of computer graphics in the mining industry. It presents a newly developed computer software package specifically designed for use in underground mining operations. This software package, developed under a US Bureau of Mines contract, 1) displays mine ventilation schematics and other representative illustrations for a real time data acquisition system and 2) uses the Bureau-owned Minefire and Ventilation Code for display of ventilation and contamination predictions on the microprocessor system. The package uses a unique system of display indexing that provides a simple yet efficient method of recalling a series of mine schematics detailing an underground operation and an alarm acknowledgment scheme that provides an effective method of identifying problem areas that may exist in the mine network. The package was written in Fortran for a 64-kilobyte, Z80-based microprocessor computer.

Jan 1, 1986

By D. C. Jillson

THE data on the critical resolved shear stress for zinc single crystals published by Rosbaud and Schmid1 showed many irregularities, as seen in fig. 1. There have been subsequent investigations,2,3 but no one has repeated this work with a wide range of orientations, with specimens of a higher degree of purity and perfection, and with improved experimental techniques in order to determine whether these variations were entirely experimental or whether they might have been due, at least in part, to some feature of the mode of deformation not known or understood. Mathewson4 and others have long felt that the glide observed in a [100]* direction between two (001)* planes in the zinc lattice might be actually the net effect of many consecutive unit glides or movements in two alternating [210] directions (fig.

Jan 1, 1951