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By W. E. Wickerman

The Magnetic Storm Monitor is an instrument that continuously records variations in the earth's total magnetic field at a fixed location. It is intended for use in conjunction with airborne magnetometer surveys. There are stormy periods when changes in the earth's magnetic field are so violent that data obtained with airborne equipment would be of little value. The Monitor provides this information so that flights may be cancelled or terminated, thus eliminating useless flying. Moreover, when some unpredictable change in the earth's field occurs during an airborne survey, the Monitor record, showing a similar event, may serve to salvage the data.

Oct 1, 1955

By Harold W. Smith

Ore beneficiation via grinding and flotation has traditionally been considered an art because, until recently, the beneficiation plants that operated effectively were those run by skillful personnel who had acquired an "eye" and a "feel" for the process. Today, thanks to technological developments of the past five to ten years, ore beneficiation can be tackled more scientifically. In properly chosen applications, two developments that can bring significant operational and control improvements to concentrating plants are: • X-ray fluorescent spectrometers-that continuously measure chemical composition of flotation process streams, and • Minicomputers-that are relatively inexpensive and highly reliable in data gathering and process control.

Jan 11, 1974

By William B. Plank

ENGINEERING educators and industries are worried about the engineering manpower shortage that is predicted as a result of the increasing demand for trained engineers not only by industry but by the armed services. This is in the face of a decreasing supply, as is shown by this and other studies. Not only has the number of entering freshmen been decreasing since 1947, because of a decrease in the number of high school graduates entering engineering, but the total number of high school graduates will continue to decrease until 1958 because of the lowered birth rate during the depression years.

Jan 8, 1951

By ir. H. Eraly

At the Zolder mine a S/7 computer is used for two purposes : - to monitor production at the coal face - to monitor the distribution of mine cars. By using sensors attached to equipment at the coal face and at the loading points, the computer provides realtime information and also summarized reports, which help management to control production better. The computer will display this information to the control room, where two operators monitor all production events and the availability of the right numbers of mine cars at every production face. All benefits obtained from the system are described.

Jan 1, 1977

By Sanjoy Shome

Recent legislation and the heightened environmental awareness of the public have brought about constraints in the location, process selection and operation of the modern electrolytic refinery. The modern electrolytic zinc process incorporating pyro, hydro, and electrometallurgy has emissions, effluents and residues which are acceptable only under severely restricted discharge conditions. Due to the necessity of maximizing zinc recovery, the additional cost of the environmental equipment has to be minimized, which may be achieved by intelligent process and location selection as well as by proper operation of the plant for maximum return to the Owner and minimum damage to the environment.

Jan 1, 1977

By George J. Conroy, James H. Green

Results of a long-term program of electrical parameter measurement in underground coal mine working sections, performed by The Pennsylvania State University under US Bureau of Mines (USBM) sponsorship, are utilized as the basis for an analysis of the electrical energy requirements during operation. A model section is hypothesized, developed from the average or most representative characteristics as determined from tabulations of the measurements. Performance factors of the model section's machine complement are then analyzed, particularly with regard to the energy required per ton of raw coal cut and delivered from the section. Results are given in kilowatt -hours per ton.

Jan 1, 1980

By Gerald M. Friedman

CONVENTIONAL usage defines emery as a natural aggregate of corundum and magnetite. Because emery bodies contain abundant spinel two types are recognized, spinel-bearing and spinel- free. Watson and Steiger1 introduced the name spinellite for emery in which spinel is a major constituuent, but this term has not been generally adopted. Spinel emery grades locally into spinel magnetite rocks with or without accessory corundum. Even this variety has been used commercially in the past. The term emery therefore applies to natural aggregates composed of corundum and magnetite; corundum, magnetite, and spinel; and spinel and magnetite.

Jan 7, 1957

By George W. Mitchell

THE property of Eureka Corp. Ltd. is located in the approximate geographic center of Nevada, 2 miles from Eureka, the county seat. The great sources of power, the Colorado, Snake, and Salmon Rivers and the rivers of northern California, are 300 to 500 miles distant, and no lines serve areas closer than 150 miles. Fuel for diesel and steam generation is available in Utah, 300 to 400 miles to the east. Eureka's railhead is 80 miles north where two trunk lines cross the county. A spur line serves Ely, 77 miles east. Good highways connect Eureka to the railheads.

Jan 8, 1953

By James R. Aggson, John C. Curran

In a cooperative research effort, the US Bureau of Mines Denver Mining Research Center and the Pittston Co. investigated floor heave ground control problems that have plagued underground coal mining of the Beckley coalbed in southern West Virginia. Floor heave is accompanied by a redistribution of stresses and loads that are associated with underground openings, causing roof and pillar problems. The floor and roof analysis techniques that were used in the USBM/Pittston investigation may have a wide range of applicability in the mining industry. Recommended orientations and geometries for mining operations are directed at floor problems, but may also enhance roof stability.

Jan 1, 1980

By P. A. Albert

THE to a transformation has been investigated by Newkirk1 in sponge titanium alloys which had been relatively slow-cooled so that several grains formed in a former grain. For a nucleated from , Newkirk assumed the following relationships and found them consistent with his experimental results: (00.1)a (110)Pll.01. II [111] Liu and Margolin,' in their investigation, found that the habit planes of martensitic in titanium consisted of planes of the families (3341, and (3441,. Using Newkirk's orientation relationship, the (3341 habit plane is found to correspond to the (1450) plane of a.

Jan 1, 1954

By José Aloisio Paione, Eudes Prado Lopes

The geophysical exploration carried out by the Brazilian government through the Mineral Resources Development Co. (CPRM) to discover and develop Brazil's mineral resources is discussed. Particular mention is made of procedures specially adapted for contracting companies specialized in geophysics, CPRM's activities, statistical data from study programs, as well as the financial investments committed. More than 500 000 km of aerogeophysical surveys have been carried out by CPRM in the last four years, and it is expected that more than 600 000 km will be flown in 1974 and 1975, at an investment of approximately $30 million.

Jan 1, 1977

By Guy R. Johnson

In view of the attention now directed to the development of the iron-ores of Virginia, and of the frequent reference in the Transactions of the Institute to the Longdale mines, it is presumed that a brief account of the methods of working and surveying these mines will be of interest. For a better understanding of such a description, a few words will be said concerning the geological character of the ore-deposit. Professor Rogers says in his preliminary report of 1835, that this deposit has " more of the character of a true vein than is usually

Jan 1, 1892

By M. G. Taverner

Research was conducted into cold briquetting dross arisings and metallurgical coke fines from an Imperial Smelting Furnace (I.S.F.) as an economic means of agglomerating fine materials for smelting in a blast furnace. A mechanism was postulated whereby strong bonds were developed within the briquettes; laboratory scale smelting trials and full scale plant trials are included in the paper with a description of a two tonne/hour briquetting pilot plant. Benefits from smelting briquettes in an I.S.F. were measured directly in metallurgical coke savings and, indirectly, by a significant improvement in sinter plant productivity.

Jan 1, 1977

By H. R. Hanley

IT is a well-known fact that the solubility of zinc compounds decreases when these compounds are roasted in contact with iron compounds, but descriptions of tests to quantitatively express the fact have not appeared in the literature. Possibly such an expression cannot be uniformly and exactly duplicated by different operators because of the variation in the personal equation. In a general way, however, the reactions between zinc compounds and iron compounds under roasting conditions will show a certain trend with changing conditions and the approximate quantitative expression of this trend appears reasonably well established by experimental work conducted for this purpose.

Jan 1, 1929

By M. P. Board, M. J. Reus

Instrumentation was installed during construction of the Silver Shaft in northern Idaho to evaluate lining behavior and rock deformation. Rock mass displacements were monitored with multiple-position borehole extensometers. Liner stress and strain were measured with concrete pressure cells and embedment strain gages. Rock displacement data from the 5,955-ft level indicate rock mass anisotropy. Liner stress and strain data reflect high in situ stresses and nearby station and raise construction. Continued monitoring and preliminary analysis indicate that concrete-lined, circular shafts are stable for high, unequal stress fields and anisotropy in deep level mines.

Jan 1, 1984

Recognizing the fact that the problems of the committee named by the Board to prepare the "official ticket for officers and Directors of the Institute are various and difficult; and desiring to assist this committee by setting forth some of the principles that should guide the committee and some of the qualifications that should be required of candidates, the following instructions are formulated and the Secretary is directed to publish them in MINING AND METALLURGY concurrently with the publication of the names of each newly appointed Nominating Committee and to send a copy to each member of the Committee.

Jan 1, 1937

By James J. Scott

A four-year program of research, development, and field testing has led to the refinement of a ground support system utilizing friction rock stabilizers, or "Split Sets," as they are known by their patented trade name. These rock anchors are a distinct departure from conventional anchors or fully grouted anchor systems, and allow control of ground movement internally in a manner that permits controlled deformation during the early phase of rock "relaxation" around a mine opening, increased anchorage per unit length during the secondary creep stage, and have the ability to strengthen and stabilize mine openings for extended periods of time.

Jan 7, 1977

By Uros Bajzelj

To mine very weak carboniferous schists subjected to high ground pressures the underhand cut-and-fill stoping method was proposed using an artificial plate roof. An experimental stope was mined using three consecutive levels. Rock pressures, deformation of the reinforced concrete plate, and the quality of stowing were evaluated. It was found that roof deformations were minimized if the reinforced concrete plate and uncemented backfill were replaced with cemented backfill containing reinforcement near the bottom. The mining method prevented the occurrence of high rock pressures at the face. The method is suitable for mining subvertical ore bodies with large horizontal areas.

Jan 1, 1984

By John Peperakis

Coal mine bumps are normally associated with pillar mining under moderate or deep cover. Severe bumps at Sunnyside, however, have not been confined to pillar lines. Many have occurred in virgin development and in localities a long way from active pillar workings. As early as 1918 bumps in virgin territory were attributed to the faulted structure in the Sunnyside area.1 Sunnyside is an old property, mined for more than 60 years. Both man-made and natural conditions contribute greatly to bump occurrences, and loss of life and great destruction of workings have resulted from some unusual bumps in recent years.

Jan 9, 1958

By W. D. Forgeng, B. F. Decker

IT has been known for almost a century' that silicon and nitrogen combine when heated to a high temperature. Three nitrides have been reported, SiN, Si3N,, and Si,N, containing 33.3, 40.0 and 42.9 pct nitrogen by weight, respectively. The existence of SisN, is well established but that of Si,N, and SiN is doubtful. The first systematic study of the reaction between silicon and nitrogen was made in 1910 by Weiss and Engelhart" who determined the rate at which silicon absorbed nitrogen at temperatures from 1250°C to

Jan 1, 1959