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By R. A. Spitz, T. C. Frankiewicz, R. E. Lueders, D. S. Davies

Further development of the Nitric-Sulfuric Leach (NSL) process has led to an improved design of the leach and nitric acid recovery steps. NO produced in the leach step is reacted with oxygen, regenerating NO2, which is sparged directly into the leach reactor. Leaching is simplified to two steps, and the nitric acid plant is replaced with an oxidation recycle gas system. Laboratory work substantiated the concept and led to selection of operating conditions. The lab work also pointed to improved process control compared to use of nitric acid as the sole oxidant. Recovery of copper from purified pregnant liquor is modified to use air agitation electrowinning improving cathode quality and lowering tankhouse costs. Economic evaluation shows reduction of capital requirements from $2640 per annual ton to $2220 per annual ton in 1978 dollars for 45 kt/a of copper production.

Jan 1, 1982

By G. A. Vissac

In continental Europe the feldspar jig is used almost exclusively for cleaning the fine sizes of coal; it operates with an artificial bed, made up generally of pieces of feldspar or of any other hard and heavy rock with good cleavages. A primitive form of this machine requiring close supervision was used in this country years ago, but output was small. The modern machines are generally air-pulsated Baum-type jigs, with capacities up to 150 tph, and treat sizes from 3/s in. to 0, usually previously dedusted or deslimed. These jigs are equipped with very accurate and sensitive automatic controls insuring satisfactory operation even at low separating gravity and with feeds irregular in quality and quantity. This paper will deal more particularly with coal cleaning separation, but the technical studies apply equally to all minerals.

Jul 1, 1955

By W. L. Freyberger, H. Alter, K. L. Woodruff, E. L. Michaels

Laboratory and pilot scale tests have been made to determine the utility of heavymedia separation, particularly a cone-type separator, as a means of recovering aluminum and other values from shredded municipal solid waste. The effect of the method of shredding on the behavior of aluminum in a heavy-media system was determined. Two-stage pilot-scale heavy-media separations were made with size fractions of shredded refuse. Recoveries of aluminum, as well as other components of the refuse, were measured and medium losses determined. The experimental results indicate that with certain reservations a heavy-media cone system can be utilized for aluminum separation and recovery from shredded and air-classified municipal solid waste. Observations made using two-stage heavy-media separation in a drum unit are included. Qualitatively, the results from the two types of separators are similar.

Jan 1, 1976

By R. L. Loofbourow

The objectives of this report are (1) to indicate what is known of natural rock temperatures as deep as 5000 ft below the surface, (2) to indicate methods for estimating such temperatures in localities where directly measured temperatures are un- available, and (3) to outline as far as possible, areas in the 48 states within which rock temperatures are likely to be low and high. The usual object of temperature measurements in deep mines and wells is to learn the temperature of air or another circulating medium. This usually differs significantly from the undisturbed rock temperature. The subject is complicated further by the variety of the thermal properties and structures of rock masses, the migration of fluids within them, the diversity of the history of rock masses and of the processes which have been at work on them during that history.

Jan 1, 1966

By Julian Nardi

Pumping solids through a pipeline is not new but until very recently other means of transportation were cheaper. Many proposed pipelines for transporting solids, while technically feasible, have not been attractive enough to warrant the financial risk involved. In some instances, the difference in transportation cost was negligible. In others, the threat of pipeline competition resulted in a slashing of rates on existing transportation to the point where a pipeline could no longer be justified. In others, a competitive product was cheaper. FIRST IN PLACERS The earliest record of solids being transported in a pipe was in the late 1850s in California placer mines. Water under pressure was used to force gold-bearing gravel up through a pipe, from 30 to as much as 55 ft, to a point where it could be discharged into a flume or sluice.

Jan 9, 1959

By John W. Straton

The President of the United States signed Public Law 91-173 on December 30, 1969 and the Federal Coal Mine Health and Safety Act of 1969 became law. The Bureau of Mines was required to promulgate regulations to implement the law. Unfortunately, some stipulations of the Act were not technologically possible. The USBM employed many new inspectors and had to instruct both old and new personnel in the requirements of the law. Mine operators and mine workers also had to be informed. There was a fair measure of inconsistency during this period. Progress is being made, however, and it is becoming easier for mining personnel to know what needs to be done. There are some unresolved questions, however, and there still appears to be an appreciable lack of uniformity in the application of the law by the many federal inspectors.

Jan 10, 1972

By A. V. Henry

THE kaolins of the southeastern United States were known to civiliza-tion as early as the latter part of the eighteenth century-and yet the GEORGIA PRODUCTION UNITED STATES PRODUCTION IMPORTS Fig. 1.-KAOLIN PRODUCTION AND IMPORTS. commercial history of Georgia kaolins may be said to begin in the year 1900. The U. S. Bureau of Mines reported for that year a production of 6885 tons of "miscellaneous" clays in Georgia. A comparison of these figures with those of 1934, when the production rose to 284,556 tons (65 per cent of the domestic production), indicates the growing economic and technologic importance of this raw material. Fig. 1 clearly shows that a part of the increase is due to a normal growth in the use of kaolinitic clays and a part is due to replacement of clays formerly imported.

Jan 1, 1937

By Edward H. Williams

In the middle of the eighteenth century John Frazier and wife, Sarah Ingraham, removed from Boston, Mass., to Philadelphia, Pa., where he was held in such esteem that we find him one of the Committee which arranged the ball at Washington's inauguration. Their son, John Nalbro Frazier, was prosperous in his mercantile career and fortunate in his wife, Anne West, who was an important personage in the early life of Professor Frazier. This cultured lady brought into the family an atmosphere of religious enthusiasm, of thoroughness and of unity of purpose. Her son, Benjamin West Frazier, inherited her traits and displayed them during a short and active life. Like his father, he engaged in mercantile pursuits, and was a member of the firm of Zimmerman, Frazier & Co. In their interests he lived for a short time in Montevideo, and on

Jan 1, 1906

By Peter L. Swanson

A microcrack process zone is frequently suggested to accompany macrofractures in rock and play an important role in the resistance to fracture propagation. Attenuation of surface waves propagating through mode I fractures in wedge-loaded double-cantilever beam specimens of Westerly granite has been recorded in an attempt to characterize the structure of the fracture process zone. The ultrasonic measurements do not support the generally accepted model of a macroscopic fracture that incrementally propagates with the accompaniment of a cloud of microcracks. Instead, fractures in Westerly granite appear to form as gradually separating surfaces within a zone having a width of a few millimeters and a length of several tens of millimeters. A fracture process zone of this size would necessitate the use of meter-sized specimens in order for linear elastic fracture mechanics to be applicable.

Jan 1, 1984

By John Hillman

Reconstruction of the British mining industry began shortly after nationalization in 1947 and continued until well into the 1950s with the support of the government. This support diminished as plentiful supplies of cheap oil from the Middle East made many coal mines uneconomic. The planned rundown which followed was foreshadowed in the 1965 White Paper which outlined financial measures to speed the closure of uneconomic collieries. The decline appeared likely to continue into the 21st century as the role of coal in UK energy requirements became less and less significant. This policy was well on course in 1973 when the oil crisis led to a complete reappraisal of the position. A government examination in 1974 of the coal industry then supported the National Coal Board's general strategy of major capital investment as set out in its ' Plan for Coal ' .1

Jan 11, 1979

By John P. Bernardi, Ralph B. Hall

Past and present phosphate production in the central Florida phosphate district has been predominantly from the unique Bone Valley formation. As these lucrative reserves are depleted, production will shift to the Hawthorn formation in all areas, but particularly so within the southern extension, where vast potential reserves of low grade phosphates exist. Use of existing plants can be extended for some years by mining deeper into the underlying Hawthorn formation, and by mining previously ignored peripheral areas if erratic combinations of the two formations. Hawthorn Production, as compared to the Bone valley, will be characterized by lower grade; lower tonnage yield, lower pebble percent of product, higher mining ratios, higher slimes (- 150 mesh) content, and more complex mining and beneficiation problems. Geological control and more sophisticated operational procedure; will become increasingly more important as the lower quality reserves replace Bone Valley production.

Jan 1, 1981

By B. H. G. Brady, C. M. St. John

Computational schemes for analysis of rock mass response to excavation, loading and other imposed changes, are employed pervasively in rock mechanics practice. Applications range in complexity from determination of stress and displacement distributions around openings, to prediction of the thermo-hydromechanical behaviour of a saturated fissured mass. While this may be taken as apparent sophistication in rock mechanics design activity, the indiscriminate use of computer methods may sometimes conceal inferior and inadequate engineering procedures. These inadequacies may not always be recognized, due to the general uncertainties which are inherent in rock mechanics investigations. This paper seeks to identify some common deficiencies in rock mechanics applications of computational schemes, and to propose ways of eliminating them. It also indicates some specific developments and applications of computational procedures, which are required to address persistent design problems in geomechanics practice.

Jan 1, 1982

By R. S. Schechter, T. R. Guilinger, P. Bobeck, J. G. Price, L. W. Lake

This paper presents the results of an experimental study on the rate of uranium and molybdenum extraction from a flow reactor. Specific variables tested are fluid throughput and flow rate, lixiviant cation, and injected pH and carbonate concentration. The ore tested was from the Felder mine in southern Texas. It contained substantial quantities of marcasite and molybdenum disulfide that competed with the uranium ore for oxidant. Flow studies showed the oxidation of molybdenum disulfide under field conditions is mass transfer controlled, whereas the uranium oxidation is limited by surface reaction rate. The rate of uranium oxidation decreased with decreasing pH. The total carbonate levels, on the other hand, were unimportant. Ammonium carbonate appears to greatly decrease, if not completely halt, the reaction of marcasite with the oxygen. This effect was not found using either sodium or potassium carbonate.

Jan 1, 1986

By Evangelo Agelopas

Steelmaking operators are familiar with the costs involved when ingot molds must be scrapped prematurely because of the failure of a stripping or turning lug. Some mold sizes can be expected to produce one hundred or more ingots per mold before normal wear causes the mold to become unserviceable. Therefore, the failure of lugs at less than the average life for that mold size represents a sharp increase in terms of mold cost per ingot ton produced. To combat these wasteful and costly occurrences, it was determined that an efficient method of replacing lugs should be developed to extend the life of molds which are otherwise in good condition. The purpose of this paper is to describe a lug welding method which has proved effective and economical. This method is known as the Oxygen and Mapp Process.

Jan 1, 1972

SEC. 1. The membership of the 'Institute shall comprise six classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6, Rocky Mountain Members. All shall be equally entitled to the privileges of membership, excepting that no member of any class whose residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the class of Member must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members.

Jan 1, 1932

By Eckley B. Coxe

I DES~RE to call the attention of the Institute to two deep vertical shafts, which are now being sunk in Schuylkill County, Pennsylvania, about miles north of Pottsville. These shafts are of interest to the mining engineer, not only on account of the novelty of the method of sinking adopted, which promises to produce a revolution in that branch of mining engineering, but also as examples of the manner in which such work should be undertaken. GEOLOGICAL SKETCH OF THE TERRITORY TO BE WORKED BY THE SHAFTS AND REASON FOR SINKING THEM. The Mammoth or E Vein of the anthracite coal-measures in that part of the Schuylkill region near and north of the town of Pottsville lies at a great depth below the surface, and has, in consequence, never been worked in that locality.

By W. J. Keep

We have found that our graphic representations were, in some cases, not perfectly understood. In the tables by which we illustrate all our tests, the records appearing in the vertical columns between the rulings are the results of the tests of iron having the percentages and characteristics noted at the top of the column. The record is made by a short horizontal line in such vertical columns. It is located in horizontal spaces, which divide the table into units of measure, to indicate the value of the record. For example, in the upper part of Table VII. is recorded the transverse strength of the series of tests with white iron and aluminum, which were reported in our former paper. The numbers at the extreme top are the test-numbers. The fractional numbers below are the percentages

Jan 1, 1890

By Paul E. Dorr, Kenneth P. Pavlich

This paper covers the practical aspects of economic analysis of mineral ventures and the application of a publicly available computer program. The paper touches briefly on the time value of money concepts and the phases of project evaluation. The most comprehensive port ion of the paper deal s with the requirements for economic evaluation, including capital expenditure categories, operating expenses, required geological and engineering data, and tax considerations. Highlights of the 1981 and 1982 tax laws are covered. A case study using the MINECO computer program will be used to illustrate the economic evaluation concepts developed. Guidelines and goals of sensitivity analysis and Monte Carlo simulation will be discussed and demonstrated on the MINECO example. The MINECO software system will be displayed as an example of a "user-friendly", interactive, and flexible computer tool available to the mining professional today.

Jan 1, 1983

By George A. Desborough, Forrest G. Poole

Marine black-shale samples of Paleozoic age in the western United States that exceed 10 wt % organic carbon contain as much as 5000 ppm vanadium, 5000 ppm molybdenum, 1300 ppm nickel, 600 pprn cobalt, 16 ppm silver, 11,700 ppm chromium, 18,800 pprn zinc, 280 pprn cadmium, and 350 ppm selenium. Depositional set- tings include: (I) continental-rise and marginal- ocean basins, (2) continental-shelf and foreland basins, and (3) cratonic-platform embayments. Most of these metalliferous organic-rich shales have not been examined for resources because rapid weathering and poor exposures preclude easy sampling of unoxidized rock necessary to determine actual concentration and residence of indigenous metals. Generally, when interval thickness is considered, the marine black shales of Paleozoic age in the western United States are richer in metals than marine upper Paleozoic black shales in the eastern United States.

Jan 1, 1983

By Charles R. Keyes

In the dry regions of the globe many silver-deposits display certain remarkable features, which at the same time are so totally unlike anything met with among ore-bodies elsewhere that they hare long presented exceptional dificulties, not only to a satisfactory explanation of their origin, but to economical milling. A most striking peculiarity of these ores is the haloid character of many of their bonanzas. To this fact more than to any other may be ascribed most of the unusual uncertainties of mining-operations in desert countries—the marvelous local richness of the ores under certain conditions and the often abrupt transition to utter poverty; the inadequacy of ordinary prospecting customs and the constant devising of new exploratory methods; the unaccountable losses in smelting and the continual change in treatment-practice. For these anomalies certain climatic conditions seem to be chiefly responsible.

Jan 1, 1912