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By John H. Harden

The Koepe system of winding from shafts is the invention of Mr. Frederick Koepe, Manager of the Hanover Coal Mine, Westphalia, one of the collieries worked by Krupp, the well-known German ironmaster. The first trial of the system was made at the Hanover

Jan 1, 1889

By J. Winter, W. C. Setzer, A. J. Goldman

ANISOTROPY in cold worked tempers of commercial aluminum alloys is manifested in deep drawn products as protuberances or ears 45 deg to the rolling direction. This reflects the {123}(412) rolling texture.' In fully annealed material, 0 to 90 deg ears in and per-

Jan 1, 1970

By Norikazu Hashimoto

SILICIDE coatings on refractory metals are often applied by transporting a silicon halide vapor to a hot metal surface . The coatings are usually grown by solid-state diffusion reaction. The diffusion is often slower than the vapor transport and hence may become rate-controlling.

Jan 1, 1968

By AIME AIME

THE meeting of the Petroleum Division at Houston, Oct. 10-12-headquarters, Rice Hotel-was preeminently a technological success. Two hundred and twenty-five attended the Thursday morning session and approximately 200 attended the sessions on Thursday and Friday afternoons and Saturday morning. Harry Power, Chairman of the Division, in his opening remarks, credited Paul Weaver and M. Albertson, respectively chairman and vice-chairman of the local committee, with working long and prodigiously in organizing the program. The theme of the initial session was indicated by Mr. Albertson in a statement relative to the estimation of developed petroleum reserves. He said that the problem of securing more accurate estimates of developed petroleum reserves existed prior to curtailment of production. With curtailment, however, the problem became an acute one. Mr. Albertson gave some of the more important reasons for this situation. Since the decline-curve method became inapplicable, the volumetric method has become the chief one used. It depends on the factors of productive formation volume, porosity, saturation, and recovery. He briefly discussed the factors necessary for application of the volumetric method. P. P. Gregory discussed the estimation of petroleum reserves in prorated lime¬stone fields (see his paper in the October

Jan 1, 1935

By J. A. B. Forster

The operations of the Electrolytic Zinc Co. of Australasia Ltd. involve the preliminary roasting of zinc concentrate from Broken Hill, New South wales, at a number of acid-making centers on the Australian mainland. The partially roasted material is shipped to the Tasmanian plant where it was formerly re-roasted prior to leaching,' but this practice was gradually abandoned in favor of the flotation of leach residue for the recovery of a concentrate containing about 22 pct sulphide sulphur and known as secontlary or Risdon concentrate.2 This change, together with increased zinc production, called for new furnaces at Risdon for the roasting of 10-50 tonst of secondary concentrcite and 90 tons of new concentrate per day. The war situation made it imperative that construction be commenced without delay and to save time it was decided to base the design on that of Skinner type furnaces which had been built in South Australia twenty years earlier. This involved some sacrifice of desirable features but did not prevent the incorporation of provisions which had enabled small Herreshoff type furnaces to roast secondary concentrate autogenously. The roasting rate in existing furnaces was 10-12 Ib sulphide sulphur per sq ft of hearth area per day, and eleven hearths, 20 ft in diam, were provided in the two new furnaces in anticipation that they would prove capable of the autogenous roasting of 130-140 tons of concentrate per day from 28-29 pct sulphur down to 4.5-5 pct, with an oxidation rate of 11-11.5 lh S/S per sq ft of hearth area per day. It was soon realized, when the first of the furnaces went into operation, that a much better performance than this might be given, and the purpose of this paper is to show how a treatment rate of 100 tons per furnace day, and oxidation rates approaching 15 lb S/S per sq ft per day have been reached. Furnace Design General specifications for the design were based on the results of experience with several other types of furnace and on the special operating conditions

Jan 1, 1950

By George H. K. Schenck

The greatest difficulty in choosing solutions to environmental problems ill a free market economy (such as ours) stems from two factors: adverse effects of pollution are largely external to the producer, and expenditures made that improve the environment result in benefits that are free to all, These two factors are sufficient to explain why the solution to many environmental problems is to be found in public action. Such action is most likely to be economic- ally efficient if it can be carried out so that industry retains the freedom to make decisions based on the free market. Two examples-a zoned discharge fee and innovation of recycling systems-illustrate the type of changes in the mineral industry that would lead to an improved environment. The first requires that ownership of the relevant public resources be vested in control agencies. The second indicates that profit opportunities existing in solid waste recycling should facilitate innovation. Both concepts can reduce environmental loadings but will require imaginative thought from persons in the mineral industries.

Jan 1, 1971

By Gail Moulton

THE oilfields in Illinois are located principally along the LaSalle anti-cline in the southeastern part of the state. The oil produced comes most largely from beds of Pennsylvanian and Mississippian age, but there is an increasing important production from deeper horizons, as will be noted under new development. The oil is largely of paraffine base, and has an average specific gravity of about 35° Baume. The rank of Illinois as an oil producer has dropped from third since 1913, when its production was exceeded only by that of California and Oklahoma, to eighth in 1923. This has been the result of failure to find new pools of considerable size to offset the declining production of the old wells and of the greatly increased production of some of the other states. The noteworthy features of petroleum production in Illinois during 1924 are: the low rate of decline for the state as a whole; the smaller percentage of dry holes; and the larger average initial yield of the new wells.

Jan 3, 1925

By J. Donald Graham, John G. Kuhn

The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an ore body, no more and no less. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. The method for controlling development drilling programs to be described was developed during the latter part of a major development drilling project at the Christmas mine of Inspiration Consolidated Copper Co. in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous ore bodies of the porphyry-copper type would be the most likely candidates for application of the technique. Discontinuous ore bodies would not be amenable. The method is based on the measurement of the linear correlation between the spatial distribution of two sets

Jan 1, 1973

By Nicklaus Heil, L. D. Clark

As political tensions in African and Asian mineral producing regions increase, the orientation of Latin America's economic development assumes importance not only in the U.S. hemispheric policy but also in our mineral-based economy. Latin America as a mineral supply source has been confronted with regional, political and economic problems which may, at best, have limited further investment and, at worst, have suggested possible repudiation of existing investments. Historically, the mining industry has provided a basis for the national economies of Bolivia, Chile and Peru, and recently the governments of these countries have sought to force increased development of the industry through new and somewhat revolutionary mineral legislation. The extent to which the mineral industries are intended to finance economic development is uncertain and the influence of this legislation on economic freedom and incentive for foreign and domestic investment is a matter for some thought. Two facts are outstanding: first, mining, at present, provides approximately 80% of the foreign exchange in Chile and Bolivia and 42% of that in Peru and, second, existing tax revenues are insufficient to finance a developing economy.

Jan 5, 1967

By D. W. Fuerstenau

Locked-cycle grinding experiments on mineral mixtures provide a means to study circuit performance in simulated continuous grinding systems. Such experiments with calcite/quartz mixtures revealed that approximately twenty-five 2-minute cycles are required before the composition of the circuit product and the recycle material attain steady state. The circulating load, after steadily increasing during the first 15 cycles, continued to fluctuate over a narrow range. Previous batch ball mill grinding of mineral mixtures has shown that breakage rate functions of minerals are time- independent but composition-dependent. In the closed-circuit grinding of ores with constituents having different grindabilities, the grinding rate parameters for the components also would therefore change during the transient period. With fluctuations in feed composition occurring randomly every half to one hour in processing plants, it is quite likely that the grinding circuit can be in unsteady state perpetually. The significance of these observations is discussed in this paper in the con- text of the models used in control schemes for the grinding circuits

Jan 1, 1984

By D. N. Sutherland

The cassiterite flotation circuit at the Renison concentrator has operated with increasing levels of automatic control since late 1981. The circuit operates at high levels of recycle which make it difficult to control manually so that the initial control strategy was to stabilize the mass flows around the circuit prior to circuit optimization. Control of the air supplies to the flotation banks was introduced to achieve this stabilization and initial results indicated that some success has been achieved, as indicated by improvements in the overall circuit performance and reduction in the stream variabilities. These improvements were gained through control of the major recycle to the roughing stage which dominates the circuit behaviour. Feed-forward control of collector addition has also been introduced successfully, but attempts to control the final concentrate grade have been less satisfactory. This work is continuing and the objective of current activity is to include the three cleaning stages in an overall circuit control scheme as a first phase of metallurgical optimization of the operation.

Jan 1, 1984

By M. J. Shulman

With the spiraling cost of exploration, all stages of exploration must be optimized. Search theory calculates the optimal distribution of effort by maximizing the probability of discovery under the constraint that the total exploration budget is not exceeded. It may help formulate strategies during the reconnaissance phase of exploration. An incremental optimization analogous to the exact solution of the search problem is introduced. In conjunction with the optimization, various stopping criteria can be defined. The stopping criteria terminate exploration in an area during a particular stage. It does not refer to abandoning exploration. The following stopping criteria were considered: the exploration effort in an area should not exceed a maximum value; the posterior target location probabilities should not be less than a percentage of the initial probabilities; the change in the posterior target location probabilities should not be less than a given value; and the change in the marginal rate of return should not be less than a given value. The incremental optimization and the stopping criteria are used to allocate reconnaissance mapping and sampling effort for phosphorite in the Sinai Peninsula, Egypt.

Jan 1, 1986

By H. L. Riley, B. W. Gandrud

As far as the present writers know, this system of flotation has not been used elsewhere in this country, but in the last couple of years it has been introduced, with minor variations, at one plant in England and one in Wales. The system has been described and discussed in a number of publications. The following is quoted from an abstract of the latest of these," a paper presented at an International Conference on Industrial Combustion in 1952. On the basis of experience to date with the commercial plants, it is believed that the kerosene-flotation process incorporates all the necessary elements to make it greatly superior to anything else now available for treating of fines in wet processes of coal preparation. Additional study and investigation are still needed, however, to determine if certain phases of the process can be improved to such an extent as to make it generally satisfactory and acceptable to the industry. Further improvements will be needed with respect to the capacities of the flotation cells and the reagent consumption.

Nov 1, 1955

By D. M. Hausen

The amenability of a given vanadium ore to any given treatment depends largely on the mineralogic combinations of vanadium in the ore. Quantitative data on vanadium mineralogy provide not only an objective basis for selection of proper treatment, but also may eliminate many time-consuming amenability studies whose results are empirical, at best. Vanadium is distributed through the interstices of mineralized sandstone ores in the form of oxidized vanadates, reduced oxides, and silicates. Oxidized vanadates, e.g., carnotite, tyuyamunite, etc., are most readily beneficiated by simple acid leaching. Reduced oxides are more slowly solubilized, but relatively amenable to most acid treatments. The layered silicates, roscoelite, mixed layered mica-montmorillonite, and chlorite, are least amenable to most acid extractions, and constitute an assemblage of vanadium- bearing clays that are common to many sedimentary deposits. Vanadium is combined principally as layered silicates in the clay fractions of many sandstone ores. Mineralogic studies in this paper are largely confined to clay minerals, and to their amenability characteristics in low pH liquors.

Jan 1, 1985

By Vincent Carlsson

A comprehensive investigation has been undertaken to clarify how pellets are affected by alkali circulating in the blast furnace. The investigation has been performed with acid and basic pellets in a special furnace. Experiments were carried out to ascertain the influence of potassium on swelling and reducibility when added at different stages of reduction. After that, the significance of the quantity of potassium added in the hematite stage was studied. A parallel experiment with sodium as the alkali component was also con- ducted. Besides these vaporization experiments the effect of alkali on softening and reduction characteristics at high temperatures was investigated. The results showed that alkali always increases swelling, especially when added in the hematite stage. The addition of alkali increases reducibility of acid pellets during reduction from wustite to 70 % reduction. The softening temperature is significantly lowered by the addition of alkali and is, in any case, lower for acid pellets than for basic pellets. The microscopic studies showed that alkali ferrites can be formed irrespective of the influence of alkali on the slag phase.

Jan 1, 1977

By Arthur T. Ward

WHEN the Board of Directors of the Institute in June 1931 approved the formation of the Committee on Eastern Magnetite and its then membership of eleven, little did any of those concerned envision that twelve years later the annual Committee luncheon would attract 34, and the technical session, jointly with the Iron and Steel Division, more than 70. Yet that was exactly what happened during the February meeting just passed. And what is more important, some members of the Committee are now predicting that by 1944 over 10 per cent of the iron ore produced in the United States will come from these Eastern Magnetite properties. Chairman Crockett, in opening the meeting, advised that due to the serious illness of Meredith E. Johnson, State Geologist of New Jersey, Mr. Johnson would be unable to brief his scheduled paper, which would therefore be reserved for a later date.

Jan 1, 1943

By John H. Bassarear, Harold W. Sorstokke

The never ending search for lower unit costs led Pima Min- ing Company's management to study various alternatives shortly after Expansion III was completed. A considerable amount of ore as- saying 0.35% copper had to be moved to maintain mill feed at the desired 0.54 % copper content, which is the overall grade of the ore reserves. Detailed investigations revealed that for a period of 8-10 yr, about 14,000 tpd of 0.30- 0.40% copper ore pass the crusher enroute to the low grade stockpile. This ore is very hard, very clean and has to be mined at a uniform rate. A six month pilot plant run testing autogenous and semi-autogenous grinding gave encouraging results. Since no mining costs need to be charged to the extra tonnage (it had to be mined anyway), the major costs would be against milling. The decision to proceed was made in August 1970. Fluor-Utah was retained as the prime design construction contractor. Ore was put through the new mill on December 29, 1971. By March of 1972 design tonnage

Jan 5, 1973

By Gail Moulton

THE oilfields in Illinois are located principally along the LaSalle anticline in the southeastern part of the state. The oil produced comes most largely from beds of Pennsylvanian and Mississippian age, but there is an increasing important production from deeper horizons, as will be noted under new development. The oil is largely of paraffin base, and has an average specific gravity of about 35° Baume. The rank of Illinois as an oil producer has dropped from third since 1913, when its production was exceeded only by that of California and Oklahoma, to eighth in 1923. This has been the result of failure to find new pools of considerable size to offset the declining production of the old wells and of the greatly increased production of some of the other states. The noteworthy features of petroleum production in Illinois during 1924 are: the low rate of decline for the state as a whole; the smaller percentage of dry holes; and the larger average initial yield of the new wells.

Jan 3, 1925

By William C. Peters

The pre-production interval, beginning with the recognition of an orebody's best potential and ending with significant production, contains time-dependent conditions well appreciated by miners but not always understood or appreciated by the landowners, investors, and legislators with whom a miner must deal. The expression persists, even outside of Western fiction, that someone has "found a mine." From a slightly more knowledgeable position, the question is asked "How long does it take to make a mine?" and an all-encompassing answer is expected. By scanning the discovery and development history of hundreds of mines and rejecting those which involve rehabilitation or expansion of older mines, some generalizations can be attempted. It should be kept in mind that while physical conditions involving the geology of the orebody and the geographic surroundings do not change markedly with time, technologic and economic conditions do change from year to year. The new methods, facilities, markets, land tenure, and politics form a pattern in which today's mines are made and which do sometimes modify the pre-production interval.

Jan 8, 1966

By Graham Swan, Ove Alm

In-situ fracture toughness experiments have been performed with a scanning electron-microscope. The rock, Stripa granite, was loaded both in tension and three-point bending using the same size notched plates. Observations, which included crack extension measurements as a function of load, are presented in the form of R-curves. The data does not sup- port the proposition that R-curves can be regarded as independent of specimen configuration for this granite. Typically crack extension was seen to begin at loads of 70-80 % failure load. Tensile specimens showed considerably greater sub-critical crack growth than the bend specimens. Evaluation of the approximate fracture toughness Km for both specimen types produced as expected erroneously low estimates Of KIC, being worst in the case of the tensile specimen. Some crack extension data for Stripa granite using the indirect methods of compliance calibration, fluorescent dye penetrant and acoustic emission are compared. In a material such as Stripa granite it is considered that no single method is without its limitations.

Jan 1, 1982