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By Lauren A. Wright

General prosperity marked the industrial mineral industries of the U.S. and Canada in 1962. For most commodities, production and sales exceeded 1961 figures, and for several commodities, all-time production peaks were reached. Many millions of dollars were spent on exploration for and development of industrial mineral deposits, construction of new plant facilities, and expansion and modernization of existing plants. This generally satisfactory state is attributable mostly to a continuing high rate of building and heavy construction. However, for large segments of the industrial mineral field, 1962 was a year of increasingly severe competition and of problems, either existing or potential, of overproduction and overcapacity. Such problems are of particular concern to the asbestos, cement, potash and sulfur industries. As in years past, the trend continued toward larger-scale operations to permit lower production costs per unit of material mined, toward more stringent quality controls and toward marketing methods that provide greater efficiency and customer convenience.

Jan 2, 1963

By G. R. Wilms

In a recent investigation1 on the properties of chromium, and of Cr-10 wt pct W and Cr-5 wt pct Mo alloys at elevated temperatures, it was found that intercrystalline cavities developed in all of these materials during tensile creep at 950°C, and that the cavities led to intercrystalline fracture. There were some interesting differences, however, between the cavities produced in the pure metal and those in the alloys; these differences, moreover, were associated with a difference in ductility. The relevant conditions of creep testing are specified in the captions to Figs. 1 and 3. Chromium showed the presence of quite large intercrystalline cavities, Fig. 1, and these were more or less randomly distributed around the boundaries. The chromium alloys, on the other hand, showed the presence of both small cavities and cracks at the grain boundaries, Fig. 3; it is apparent that the cracks are formed by the linking together of the small cavities. Moreover, the cavities and

Jan 1, 1960

By W. C. Elmore

THE magnetic powder method, long used. for roughly mapping mag-netic fields, has recently been refined 1,2 for investigating the microscopic variations in the surface magnetization of ferromagnetic crystals. Bitter2 first discovered regular powder patterns connected with the crystal structure of such specimens. Several other investigators3 have used Bitter's original technique, with slight modifications, to study the varia-tion of the patterns with variations in the magnetizing field applied parallel to the surface, and their dependence upon the state of strain, of polish and of crystal cut. All of the explanations of these patterns on metallic ferromagnetics have been couched in general terms. In a preliminary report we have described an improvement in the powder technique which led us to the discovery of a new effect throwing con-siderable light on the magnetic secondary structure of alpha iron4 and of nickels single crystals. We now report additional evidence confirming the existence and stability of a magnetic block secondary structure.

Jan 1, 1936

By C. T. Sheeran, J. C. Franklin

A commercially available microprocessor-based system capable of monitoring 512 channels has been interfaced with monitors for radon, working level, air velocity, and fan power. The basic system utilizes both 280 and 8080 microprocessors in a desktop central processing unit (CPU). CPU hardware includes keyboard, video display (CRT), and disk drive; a printer is used to keep permanent data records. Signals from all channels are transmitted to the computer in digital form where they are processed for alarm status. Software developed for the system allows for audiovisual alarms in the event of low and high readings, rate change, change of state, or communica- tion failure. Up to six channels can be continuously displayed on the CRT for current readings. Shift reports and trend logs may be generated to help the ventilation engineer determine average working levels and ventilation effectiveness. Additional software permits the operator to program command sequences which may be used to automatically restart fans after a power outage.

Jan 1, 1982

By Thomas D. Henderson, Donald E. Crowell

INTRODUCTION This paper presents a "case history" of the steps taken to estimate capital and operating costs for a typical porphyry copper concentrator of ±9,070 metric tons (10,000 short tons) per day capacity. The concentrator described herein is hypothetical, but is based on experience and is, in effect, a composite of several actual projects. The numbers used are illustrative only and do not represent actual costs at any particular concentrator. These numbers are, however, representative of typical milling costs at one point in time, and. are sufficiently accurate to illustrate the cost estimating procedures described in this paper. It is not possible to publish actual, current milling costs and, in any event, actual cost figures quickly become meaningless in today's economic situation with various costs all rising at different rates. The paper is divided into three parts: (1) order-of-magnitude estimate, (2) feasibility study estimate, and (3) discussion of differences between estimated and actual costs.

Jan 1, 1978

By Fred D. DeVaney

MINNESOTA taconites are extremely hard, and fine grinding is required to produce an acceptable concentrate. To reduce grinding costs, waste material is rejected by magnetic separators as soon as it is liberated. Cyclones are now used in all Minnesota taconite plants to close the grinding circuits. Erie Mining Co. installed its first grinding section at Aurora, Minn., in 1948-a 9 ½ x12-ft. mill and a fine grinding section consisting of a 10 ½ x12-ft ball mill in closed circuit with a duplex 60-in. spiral classifier. Concentrates from the magnetic cobbers treating the rod mill discharge passed directly into the classifier; the ball mill discharge was also treated in magnetic separators and the concentrate from these machines also went to the spiral classifier. Both concentrates passed through ac demagnetizing coils. It is axiomatic that for proper classification the material in suspension must be well dispersed, and it follows that magnetic concentrate must be almost completely depolarized if classification is to be successful.

Jan 8, 1957

By Eli Sani

Investment in the mineral industries-particularly in the mining industry-differs from investment in nonminera1 industries in that the latter have an indeterminate life, assumed to be perpetual, and are not called upon to replace the firm's original investment. In mining ventures, on the other hand, once the ore bodies are depleted the mine has no economic value; the original capital investment must be returned to the investor by the time the ore is exhausted. A mining venture is also characterized by the significant cost and time associated with the exploration phase. A myriad of samples must be taken, geological features investigated, and ore grade assured. In addition, most mining ventures require substantial capital expenditures aggregating several hundred million dollars for a number of years before the project begins producing any revenue. Any theoretical model employed in evaluating a mining venture, as well as similar mineral ventures, must take all these factors into consideration.

Jan 5, 1977

By R. P. Rothwell

A Reference to the geological map of Alabama shows the Goalmeasures of that State to form three distinct fields. The Coosu, or most easterly, contains about one hundred square miles ; the Cahaba, or middle field, which is also the most southern true coal in the United States, contains about 230 square miles ; and the Warrior field, which contains in the State of Alabama some 5000 square miles, is the southern extremity of the great carboniferous deposit, which extends through Pennsylvania, West Virginia, Kentucky, Tennessee, and Georgia. But very little has yet been done towards developing those coalfields, partly owing to the absence of all commercial manufacturing enterprise in the South under slavery, and partly owing to the want of capital and the disturbed condition of the South since the war. During the past three or four years I have devoted a large part of my time to the examination of the coal and iron ores of this range,

By Ferron A. Olson

Occasionally it is good to consider the past, assess the present and project the future. Curriculum, enrollment, matriculation of graduates and changes in industry which influence mineral education are all relevant for determining what changes will be needed in educational institutions to support growth and development in the United States. It would appear likely that with environmental pressures, energy needs with present stress in fossil fuels and general societal needs for metals and minerals that mining and metallurgical engineering faces a period of growth and may be on the threshold of a new era with a vitality that has not been enjoyed for several decades. The following information is based on material obtained through questionnaires received from twelve schools accredited in mining or mineral engineering (out of 18 in the U.S.), 2 not accredited and 5 which no longer have mineral engineering disciplines. The schools presented do not include the smaller nor larges of the undergraduate programs in mining engineering.

Jan 8, 1972

By T. M. Olson, B. G. Lewis

The adsorption of selenite on bentonite, kaolinite, and an iron--coated illite was studied to determine the importance of several soil variables on selenite removal from uranium mill tailings pond seepage. Adsorption capacities of the clays of selenite varied by orders of magnitude and decreased in the following order: illite > kaolinite > bentonite. Maximum adsorption of selenite on the clays was observed between pH 2.5 and the clay's zero-point-of-charge. Substantially less selenite was adsorbed on these clays in actual mill tailings solutions than in model systems. Virtually all selenite was removed from the tailings at pH 7. The principal removal mechanism at this pH is suggested to be the adsorption of selenite on freshly precipitated metal hydroxides. It is concluded that selenite can be removed from tailings seepage in soil or in clay liners in the presence of kaolinitic clays and iron oxides. Selenite would also tend to be removed from tailings seepage in calcareous strata.

Jan 1, 1984

By G. Van Esbroeck

THE copper mines of the Katanga region in the Belgian Congo lie along the same mineralized belt as those of Northern Rhodesia. There are two distinct types of deposits in that belt, the dolomitic and the quartzitic. In the dolomitic type the metallic minerals are found in a dolomitic limestone country rock. Through oxidation and enrichment, large deposits of high-grade oxidized copper ores were formed, some of which are being worked by the Union Miniere du Haut Katanga. Such deposits are all in Katanga. The quartzitic deposits are found in Katanga and Northern Rhodesia. Here the primary mineralization occurred in sandstones and quartzites, in horizons stratigraphically lower than the dolomites. These rocks are not favorable to secondary enrichment and the oxidized zone is poorer than the sulphide zone, which alone contains the ore. There are also in Katanga a few ore-bearing veins. One of them is being worked in the Prince Leopold mine at Kipushi.

Jan 1, 1939

By J. D. Prater, H. R. Spedden, E. E. Malouf

Application of research findings to the old art of leaching copper from copper-bearing mine waste has resulted in a significant contribution of copper to over-all copper production. For example, at the completion of the current expansion program at the Kennecott properties in the United States, copper produced from waste dump leaching will amount to about 25% of the total production, whereas formerly only 2% was derived from this source. This planned expansion of copper leaching focused attention on the problem of developing more efficient methods for the recovery of copper from greatly increased volumes of copper-bearing so1utions.l Detailed investigations made in laboratory pilot plant and plant tests for the recovery of copper from copper-bearing solutions have included electrowinning, solvent extraction, ion exchange and cementation with iron in launders, precipitation drums, activated launders, and precipitation cones. The results of these investigations have led to the development of a precipitation cone-type recovery system having advantages over older methods.

Jan 4, 1966

By Akira Ishizu, Nobuo Matsui, Hideo Yamamoto, Tatsuya Nagahama

At Kamioka Mine of Mitsui Mining & Smelting Co., Ltd., Japan there are three mills, treating a total of 6400 t/d of lead-zinc Ore. In the lead-zinc bulk differential flotation at Shikama Mill the addition of reagents is automatically controlled by the feed rate, the lead and zinc content in feed, froth and tailing, the pH and the concentration of cyanide ion in the pulp. As the zinc thickener overflow at Shikama Mill contains CU(CN)3--, ZnS, CdS, CN-, xanthate and frother, all the ingredients in the over- flow other than CN are floated by using the Nagahm flotation machine, and the water containing only CN- is effectively recycled to the lead- zinc differential flotation circuit. In the lead-zinc straight differential flotation at Mozumi Mill, the overflow of tailing pond is recycled especially to the cleaning flotation circuit by decreasing the pulp density. Thus the integrated recycling of wastewater greatly reduces environmental problem and in addition, it generates sizeable profit.

Jan 1, 1977

Birmingham - A City With a Future COURTING new industries is the time honored duty of the chambers of commerce; but Birmingham, until recently, has done its courting without the benefit of troubadors. This is all changed now for the iron and steel industry is singing an enticing song about steel priorities for new industries from Birmingham's own mills. Along with the increasing industrialization of Birmingham there has been a marked influx of industry into the Southeast and neighboring areas in the south central states which augurs well for business in Birmingham. This important stronghold of the foundry industry (consuming 95 pct of Birmingham's merchant pig iron in 1950) has been the source of important announcements about additions to steel ingot capacity. The virtual abolition of basing point pricing gives the Birmingham iron and steel industry an advantage in the South's new markets. This means more business for Birmingham, but the problem of raw materials supplies is posed.

Jan 12, 1950

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1935 are available at Institute headquarters, unless otherwise noted. They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS. Copies of the TECHNICAL PUBLICATIONS have been mailed to members of the Institute that are registered in the different classes: A-Metal Mining; B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Institute of Metals Division; F-Coal Division; G-Petroleum Division; H-Industrial Minerals Division (Nonmetallics); I-Mining Geology; J-Mineral Industry Education Division; K-Mining Administration; I-Geophysical Prospecting. Other members may obtain copies by writing to the Secretary. Copies of CONTRIBUTIONS may also be obtained from the Secretary's office. Additional copies are sold at the rate of 1 cent per page; minimum charge, 25 cents. Nonmembers may purchase the papers at the prices mentioned. [ ]

Jan 1, 1936

By H. I. Ashby

INITIAL development of the south orebody at San Manuel is being carried out from the No. 1 and No. 2 shafts. The haulage and grizzly levels are being driven to develop the upper one third of the massive hydrothermally altered and fractured monzonite orebody. This first haulage level has been placed at the 1475-ft level with a grizzly level 60 ft above. The grizzly level will be connected to all service shafts so that men and supplies can come down to the grizzly level and go to working places without congesting the haulage level. These connections are also a vital part of the ventilation plan. The haulage level is being advanced along the north and south fringes of the orebody and connections are being driven to the three shafts now under construction. The No. 1 and No. 2 shafts will serve the development work with supplies, skip hoisting, and ventilation at each shaft and the two shafts are connected on both the grizzly and haulage level.

Jan 7, 1954

By George L. Lyle

WITH the advent of World War II, the need for agricultural products rose phenomenally and caused a similar increase in demand for plant foods of which phosphate rock is one of the more important raw materials. By the close of the war or shortly thereafter, all of the operating companies were expanding their production facilities. Many companies installed modern bulk material handling facilities. Designs varied, but were generally of the overhead trestle type of storing conveyors. American Cyanamid studied these various installations but was not satisfied with the conventional system because of high initial cost, increased maintenance problems in the way of painting structural steel that might be submerged in stored materials, and because of slightly increased operating costs. As a consequence of these economic analyses, conferences were held with the various conveyor manufacturers to develop a better method of storing and reclaiming. After considerable engineering study, one conveyor manufacturer suggested the unique system which was installed in 1950.

Jan 8, 1954

By Charles H. Mitchell

British Columbia is enjoying a period of sustained high-level activity in all aspects and sectors of its mining industry. The total value of mineral production for 1962 was in excess of $229 million. This was the greatest total value attained for any year to date, exceeding the previous record year of 1956 by more than $40 million. It appears reasonable to expect that value of production for 1963, stimulated by increased production attained during the year, and by improved metal prices for some of the major products, will be substantially in excess of that recorded for 1962. Elsewhere in this issue appears a detailed report of prospecting and exploration activity in the Province. For the purposes of this review it is sufficient to state that the level of prospecting and exploration activity during the past several years has been greater than at any previous time and that there does not appear to be any slackening in activity or interest.

Jan 12, 1963

By Ramachandra Rao

THE occurrence of copper ores at Garimenapenta, 14 59 min 30 sec N Lat., 79 33 min 10 sec E Long., in Nellore district, Madras State, India, has been examined and investigated on numerous occasions during the past two centuries.' No tangible orebody was ever located as a result of all the ex- tensive trenching and shafting done in the area by various agencies. However, during 1933 Messrs. Piepmeyer & Co., a German firm engaged by one of the leaseholders of the area, carried out an electrical survey using inductive methods.' On the basis of certain strong indications found in their survey, they recommended that the prospect be proved by drilling or shafting. But for want of financial backing no further work was carried out. When the Madras government more recently proposed investigation, Dr. Krishnan, then Supt. Geologist of the Madras Circle, urged that before further costly ventures were carried out a test geo-

Jan 1, 1954

By Carl Henrich

In the planning and erection of smelting-works, especially of such as contain the modern large water-jacketed blast-furnaces, we are often confronted with an insufficiency in the watersupply. It may be impossible to find in the immediate neighborhood of the selected site a sufficient supply to furnish the jackets with cold water. Or there may be enough water for this purpose, but it may be highly charged with scale-forming minerals held in solution. Or, the main water-supply, if pumped from the workings of a mine, may carry iron- or copper-salts, or even some free acid in solution, all of these substances being derivable from the oxidation of sulphuret-ores in the mine. Moreover, such mine-waters sometimes contaminate the waters of the creeks, so that these become unavailable, and we have to fall back on an inadequate supply of pure water furnished by some spring or springs, entirely too small in

Jan 1, 1896