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MR. CHARLES F. RAND, President, BUTTE, MONT., APR. 29, 1913. American Institute of Mining Engineers. Dear Sir: In conversation here with Mr. Sales, who is much interested in the work of the Committee on Mining Geology, he made a suggestion which you may be interested to hear. He, and many of us, are interested in papers along our lines of special activity, as they appear from time to time in the Institute Transactions, and often take these papers with us into the field. It appears that the work of special committees which are being formed is likely to result in a much greater number of available papers than the Institute has ever before been called upon to publish. This year's Transactions, for instance, have to be published in two volumes. Why would it not be a good plan, instead of printing heterogeneous volumes, to classify the papers into several volumes, under main headings such, for instance, as iron and steel, precious metal mining, and mining geology ? We would, in fact, be very glad to suggest this as a topic for discussion, if you think it wise, in response to the Secretary's letter of April 18. Very truly yours, J. W. FINCH.

Jan 5, 1913

By P. J. Connors, William J. McCormick, F. B. Olender, Jerome F. Sheldon, Donald T. Mylar, Edgar T. Gregory, Owen S. Roberts, H. Colijn

A quiet revolution has taken place in the conveyor belt industry. Man-made materials, improved production facilities, better splicing techniques and emphasis on repair and maintenance have all contributed substantially to lowering material handling costs for the mining industry. Formerly the rubber industry had only cotton for a belt carcass and tree grown rubber for the protective cover. Monofilament rayon, with desirable elongation and elastic properties, was the first synthetic fiber to be used in place of cotton. But wet strength and other limitations restricted its use, and the conveyor belt industry turned to nylon.

Jan 3, 1972

By E. S. Leaver

THE purpose of this paper is to describe, in a general way, gold-dredg-ing operations in California, with particular reference to unusual features, including types of deposits and recent attempts to improve the recovery of the gold. DREDGING AREAS The gold-bearing formations that traversed the western slope of the Sierra Nevadas for a north and south distance of some 300 miles furnished the immediate source of the gold found in most of the placer deposits of California.. Erosion through a long period carried the gold, together with various forms of partly disintegrated material, to lower elevations and formed placer deposits. Through the classifying action of water in motion, the coarser gold and heavier material of various kinds were deposited relatively near the source; consequently, in' the higher moun-tain country, old river channels were worked feverishly during the early California gold-rush days because of their high gold content. With the working out of these known high-grade channels, and from the knowledge thus obtained of prehistoric stream beds, drift mining was started and flourished until about 1890. Even today many drift mines are operating with the objective of opening other old Tertiary river channels that have been covered by volcanic flows.

Jan 1, 1937

By G. G. Griswold, B. S. Morrow

The copper-bearing ores concentrated at the Anaconda plant of the Anaconda Copper Mining Go. are principally a mixture of copper and iron sulfides associated in a gangue consisting of quartz, lightly altered granite and feldspars, with sphalerite and galena and more rarely barite and hubnerite as accessory minerals. The predominant sulfide is pyrite. The copper minerals present are: chalcocite, bornite (erubescite), enargite, chalcopyrite, covellite, tetrahedrite and some tennantite. Normal concentrator practice removes a slime prior to ball-mill grinding. The deslimed ore is ground to approximately 10 per cent plus 65 mesh for flotation. Two selective flotation circuits are used, one for deslimed ore and one for slime. Microscopic studies of concentrator products disclose such an interlocking of copper minerals with pyrite that any material increase in concentrate grade entails additional grinding unless recovery is sacrificed to a considerable extent. During the latter part of 1931 and the early part of 1932 the problem of producing a high-grade concentrate (40 per cent Cu) with at least no

Jan 1, 1935

A severely technical article, however well written, can not be an agreeable form of literature. It suffers from the defects of its qualities. One defect is a congestion of language, due to a multiplicity of adjectival nouns. The sentences are packed with words of unpleasing sound, charged with complex ideas, crowding one another so closely that the phraseology moves like an ice-pack in Bering Sea or a log-drive in a river; the undercurrent of meaning may continue to move, but the surface is obstructed. This verbal congestion is made evident by ugly compoundings, many of which are adopted by the technical writer in the mistaken belief that they give directness to his statements. For example: A unanimously approved scheme "A scheme unanimously approved " The continuous temperature record "The continuous record of temperature " To stimulate interest in synthetic plant construction "To stimulate interest in the construction of synthetic plants " In smelters reverberatory-furnace firing with powdered coal has been practised for a decade. "In smelting, the firing of reverberatory furnaces with powdered coal has been practised for a decade." A tar consumption of one pound per ton "A consumption of tar at the rate of one pound per ton " A mechanical ventilating system

Jan 1, 1931

The conservation movement, initiated during the time of Gifford Pinchot and Theodore Roosevelt, has gradually taken hold of the popular imagination of the American people; and today, although it is little understood, it is an accepted doctrine. But the subject should not degenerate into cheap and misleading publicity. In the wise development and use of human and material resources lies the answer (Fig. 4). Conservation does not mean the parsimonious and misguided avarice of the miser, but the prudent and intelligent use of all types of resources, and the opening of a way for the use of those potentialities that lie just beyond the horizon and wait for man's constructive efforts to make them available. Conservation consists essentially in not emptying the pools of primary wealth before the minds of men, guided by ingenious research, have found ways to replenish them from sources as yet untapped. To advance successfully along this path, man should be guided by science and by a decent understanding of his obligations to his fellow man and particularly to his children and his children's children. Two pathways branch from this general road. One is the restraining of those spendthrifts who would throw away our national heritage for the sake of a cheap and irresponsible enjoyment of the present. Conservation in the generally understood sense usually has meant

Jan 1, 1950

By Theodore H. Eyde

The Superior Oil Co. drilled two holes, 4720 and 5940 ft, respectively, using conventional oilfield rotary drilling equipment. The results indicated that large rotary drills can be adapted to mineral exploration purposes with few modifications. The principal advantages are: a large hole diameter, excellent samples of cuttings, a geolograph which is a constant drilling record, rapid penetration even in hard rocks, and the ability to use electric logs for measuring the properties of the rock being penetrated. The disadvantages are the high cost of mobilization, drilling, and oilfield service at remote locations. Though the oilfield sampling techniques are adequate for identifying lithology, improvements are necessary to obtain representative samples for analytical purposes. As deeper targets are explored, mineral exploration organizations will have to resort to rotary drilling.

Jan 1, 1975

By Walter C. Smith, O. J. Seeds

METALLIC bismuth was known in the Middle Ages and the name is supposed to come from the German Wismut. The origin of the German name is uncertain. References to bismuth are found in the writings of Valentine, Paracelsus, and Agricola between 1450 and 1550. Early specimens of bismuth were very impure and often were confused with antimony, tin, and zinc. About the middle of the eighteenth century, J. H. Pott, C. J. Geoffroy, and Torbern Bergman succeeded in producing fairly pure bismuth and showed it to be an elementary metal similar in many respects to lead. H. S. Washington has estimated that bismuth occurs in the earth's crust about as abundantly as tungsten and silver; i.e., to the extent of 10-6 or 10-7 pct. It is found as native metal, both alone and associated with tin, copper, and other metals, and in a large variety of ores. The important ores are the sulfide (bismuthinite), the oxide (bismite), and the carbonates (bismutite and bismutosphaerite) . Other occurrences of bismuth are in the vanadate (pucherite), the selenide (guanajuatite), the telluride (tetradymite), and in many complex sulfides, arsenides, and antimonides. Bismuth minerals have been found in many parts of the world but very few of the bismuth deposits have been of economic value, the oxide ores from parts of China being the exception. The major portion of the bismuth production of today is the so-called by- product bismuth. Bismuth often occurs in ores mined and treated primarily for other metals, and during the treatment of these ores

Jan 1, 1953

By E. H. Cho

INTRODUCTION Activated charcoal has been used for several centuries in many capacities including the recovery, isolation and purification of various materials (1). The first use of charcoal in a gold metallurgical system was in the extraction of gold after chlorination (2, 3,4). The gold was dissolved in a chlorine system and subsequently filtered through charcoal. The application of charcoal with cyanide extraction was patented by Johnston (5) in 1894 and adopted commercially in Australia in 1897. The process consisted of dissolving the gold and silver in a potassium cyanide solution and passing it through a series of charcoal filters. The charcoal was subsequently smelted to recover the gold and silver. The interest in the use of charcoal diminished in the first part of the twentieth century as the practice of the use of zinc as a precipitating agent increased. However, in 1916, the Yuanmi Mine in Australia replaced their zinc precipitation plant with a charcoal adsorption plant. In 1926, Scott and Gross (7) of the U. S. Bureau of Mines con- ducted extensive research on the adsorption of gold and silver from cyanide leach solutions. Among their findings was the result that the most important factor in improving the adsorptive power of charcoal was heat treatment with oxidation by air or steam. The work of Zadra (8) in 1952 stimulated renewed interest in the use of activated charcoal in gold and silver recovery with the development of a method of recovery of the gold and silver from the charcoal other than its destruction by burning. The process involved simultaneous desorption

Jan 1, 1983

By Byron S. Gottfried

This paper describes a comprehensive computer program, developed under the joint sponsorship of the U.S. Environmental Protection Agency and the U.S. Bureau of Mines, that simulates the performance of coal preparation plants. A typical plant configuration may include several different washers, crushers, and screens as well as stream blenders and stream splitters, interconnected in whatever manner the user may specify. The program will predict the mass and energy yields of each unit and the properties of each flowstream (weight, ash, pyritic sulfur, total sulfur, and energy distributions), provided the feed properties and appropriate values for various control parameters are given. The program is used to assess washability characteristics of different coals, to determine the effectiveness of different plant operating conditions, and to compare the performance of various plant configurations. A brief description is given of the methods used to carry out the calculations for each type of unit. Results of some calculations are also presented. These results illustrate the versatility of the program for analyzing both simple and complex plant configurations. The paper concludes with a description of other accomplishments and future plans.

Jan 1, 1977

By H. A. Schwartz

THE spheroidal form of the temper carbon nodules in malleable cast iron and of the graphite mottles of "mottled" cast iron suggests that in both all the graphite in a given mottle or nodule grew from a single center of crystallization or nucleus. ? There is, however, a distinct metallo-graphic difference between the mottle and the nodule; the area of mother metal impoverished in combined carbon by the crystallization of graphite in a mottle is practically coextensive with the ramifications of the graphite, while the impoverished zone of metal corresponding to a given nodule is always larger, and usually much larger, than the approximately spherical mass of graphite crystals forming the nodules. Furthermore, the mottle probably is formed during freezing and the nodule almost always at a considerably lower temperature. Assuming that the nodules or mottles can be used as a measure of the existing nuclei (capable of germination) we propose to record certain observations as to the graphitizing reaction in the light of the number and habits of growth of these nuclei. The present authors, in cooperation with others1-7, have reported upon various cognate aspects of the problem. The fact that temper carbon is a mass of flakes and not a solid granule has become well recog-nized since the introduction of an improved polishing technique8,9,10 for cast iron. The problem of deriving from the circular planar intercepts

Jan 1, 1936

By J. B. Stubbins, D. F. Coates, K. L. McRorie

Twenty-two pit slides that occurred in two Canadian open pit mining properties are analyzed. Information on the results of laboratory tests of the rocks and a brief description of the geological environment are also presented. One deduction from the study is that slides seem to be predictable by using established theory. This corroboration indicates that, contrary to normal mining practice, the appropriate slope angle should vary with the height of the wall. In addition, if the general ground water level around an open pit can be reduced, the appropriate slope angles of the walls could then be increased by a determinable amount. The ultimate objective of these investigations is to determine the relationship between the percentage probability of failure of any slope designed with specific strength paraheters. With this relationship it would then be possible to determine optimum slope angles. Because of changes in various economic factors, open pits are now being mined to much greater depths than previously. The need to keep stripping ratios low without endanrrerine.-- lives and equipment provides a strong incentive to determine the maximum practicable wall slopes. Applied research work is currently being conducted to establish the methods for analyzing optimum slopes.

Jan 1, 1963

By John Birkinbine

Among the notable deposits of iron-ore, the Iron Mountain at Durango, Mexico, is prominent. But, although it has been noticed in records of travel and official reports for three centuries, the statements made concerning it have been so largely alloyed with improbabilities that general credence has not been given to data relating to the Cerro & Mercado, that being the name by which this remarkable mountain of ore is known. Location. Geographically, the mountain is centrally located, being situated immediately at the City of Durango, which is distant in direct lines (as the crow flies) as follows: From the Rio Grande River at El Paso, Texas, in the north, 510 miles; from the same stream at Laredo, Texas, in the northeast, 410 miles; from Tampico, in the east, 475 miles; from the City of Mexico in the southeast, 520 miles; from Mazatlan in the west, 110 miles. At El Paso, the standard-gauge Mexican Central Railroad, and at Laredo, the narrow-gauge Mexican National Railroad, enter Mexico. Tampico is a prominent Mexican port on the Gulf of Mexico, and Mazatlan occupies a similar position on the Gulf of California. To reach Durango from Laredo or Tampico, spurs of the Sierra Madre Mountains must be crossed, and between Mazatlan

Jan 1, 1885

By P. A. Tucker, T. B. Rhinehammer, D. E. Etter, J. E. Selle

The Ce-Cu phase diagram was investigated by differential thermal analysis and rnetallography. Two congruent melting compounds, CeCu2 (817°C) and CeCua (938°C), and three incongruent cornpounds, CeCu (516°C), CeCu, (796°C), and CeCu, CERIUM and copper have been suggested as possible diluents in a liquid-plutonium fueled reactor. As part of the determination of the Ce-Cu-Pu ternary phase diagram, a review Of the Ce-Cu system (798°C), are present in this system. Eutectics exist at 28 at. pct Cu (424°C), 74 at. pct Cu (756°C), and 91 at. pct Cu (876°C). The purity of the cerium used has an important effect on the results obtained by differential thermal analysis. was considered necessary. Previous work by Hanaman was conducted with relatively impure metal: 96.7 pct Ce with 2.5 pct other rare earths and 0.5 pct Fe as major impurities. The metal had a melting point of 715°C as compared to the melting point for pure cerium of 804°C as reported by Spedding and Daane.2 Results presented in this work were obtained primarily by differential thermal analysis (DTA) and metallographic examination of slow-cooled or quenched samples.

Jan 1, 1964

By T. Nakao

Fujiwara quarry had been operated by the glory-hole benchcut mining system, but as it became difficult to meet expanding demand with this system, a central-shaft mobile crushing plant (MCP) system was introduced in 1979. This MCP is equipped with a hydraulic walking system manufactured for the first time in Japan. Central-shaft mining is now the common mining method of Japanese limestone quarries. With this method, crushing facilities are usually installed at the bottom of the shaft. But at the Fujiwara quarry, MCP was adopted and installed on the quarry surface. Many MCPs are operated in foreign countries, but few examples exist in Japan. Normally, Japanese limestone deposits lie in high mountain, obviously making it inconvenient for MCPs to walk in and around the quarry. This difficulty, however, was overcome, and the MCP has operated satisfactorily and efficiently for two years since its installation. To overcome difficulties in the central-shaft MCP mining system, two mining methods are employed: the slice-down method and the block-cut method.

Jan 1, 1985

By Roussey Roussev

The use of chemical additives on grinding is of significant importance considering the high energy consumption of grinding processes. My research indicates that the dispersant approach explains the effects, in this particular case of wet grinding. Further, the dispersant approach combined with torque measurements give the possibility of clarifying the mechanisms involved when using grinding aids. I find the conclusions derived from the data obtained to be correct and useful for grinding. In general, I agree with the explanations. However, I would like to discuss several additional points that I consider to be important, and in the same time to mention some of my own results from investigations similar to those presented in the study under discussion. The "bed volume concept" and the change of slurry viscosity explain adequately the data plotted on [fig. 3], in conjunction with [Figs. 1 and 2]. However, the significant increase of the average torque in the case of 83% solid with XFS-4272 introduces the necessity of establishing the optimum of percent solid when dispersant is used. For example, the optimum percent of solid for different materials varies. One of the reasons is the material's mass density. On the other hand, it is necessary to determine the concentration of the chemical used. Because of this, it would be interesting to know how the cited concentration was selected.

Jan 1, 1983

By Edgar S. Cook

The Warwick furnace at Pottstown, Pa., constructed for anthracite fuel, is, as may be remembered, 554 feet high, with 15; feet bosh. The actual working height from stock-line to bottom is only 474 feet, the bell-and-hopper taking up 8 feet. During the year 1886 we used mixed fuel, in the proportion of three-fourths anthracite and one-fourth coke. The total product of iron was 30,6299 tons of 2280 lbs., being a weekly average of 589 tons, including all ordinary and extraordinary stoppages. Deducting the latter, the weekly average would be about 600 tons. The fuel-consumption for the year was 1.2 tons per ton of iron, while the ore-mixture yielded 52 per cent. of iron. For about two months during the summer of 1887 we were obliged to run on anthracite exclusively, owing to the Connellsville coke strike. In the fall of 1885, in relining the furnace, the crucible had been built 8 feet 9 inches in diameter, with the view of using regularly one-quarter of coke (the largest previous diameter having been 7 feet 5 inches), and we felt somewhat apprehensive of the results when compelled to use anthracite only. The average of seven weeks' run on coal, as compared with the average of the seven corresponding weeks of 1886 (using one-quarter coke), was as follows:

Jan 1, 1889

By S. L. Couling, G. W. Pearsall

MOTT and Hainesl have summarized the available techniques for the examination of aluminum and some anisotropic metals under polarized light. Many of these techniques are rather complicated and cumbersome. This note presents a simplified procedure for using polarized light to obtain information about the crystallographic orientation of any particular grain in a magnesium alloy. Since other hexagonal metals are more anisotropic than magnesium, similar methods might well be applied to them. Ernst and Laves2 produced a double-refracting layer on magnesium alloy specimens by SuCCeSSiVe etches in solutions of perchloric acid in alcohol, magnesium perchlorate in perchloric acid and alcohol, and calcium and magnesium carbonates in water. They examined their specimens under polarized light and were able to determine the direction of the hexagonal axis in any particular grain from a measurement of the extinction behavior of that grain. The disadvantages of their technique were the complexity of the etching procedure and the explosive hazard of the perchloric acid-alcohol solutions. Results equivalent to those of Ernst and Laves were obtained in this investigation after etching specimens for 6 to 8 sec in an acetic picral solution containing 100 parts 6 pct picral, 10 parts distilled water and. 5 parts acetic acid. A. similar etch has been used by George3 in earlier metallographic

Jan 1, 1958

By Fred D. DeVaney

W. O. Philbrook (Carnegie Institute of Technology, Phila.)—Mr. DeVaney's paper is a valuable addition to the growing technology of the magnetic roasting of lean iron ores. His furnace is ingeniously designed to permit close control of the process and to achieve high thermal efficiency by counter-current heat exchange and the withdrawal of both solid and gaseous products at relatively low temperatures. The principle of using a lean reducing gas to avoid over-reduction of the ore even at high operating temperatures (for rapid re-action rate) is thoroughly sound. The gas analyses and flow rates reported, however, are internally incon- sistent and render suspect any details of a heat balance based upon them. While it is entirely proper to consider the entrant gas as a reagent and to account only for the heat evolved by consuming a portion of the gas, many operators are accustomed to a heat balance using the total calorific value of the reagent supplied; and comparison of heat balances made with different bases of calculation can be quite misleading. Since Mr. DeVaney's paper is likely to be cited frequently in future discussions of magnetic roasting processes, it seems worth while to point out the internal discrepancies and to give alternate values of heat requirements for different bases of calculation.

Jan 1, 1954

By Byron E. Eldred

Generally speaking, the practical study of combustion has been made mainly from the stand-point of the steam engineer. This narrow view-point has left open a large field for scientific research on the application of combustion in other arts, where the conditions of heat-utilization are widely different from those presented in the steam-generator. The great economic importance of the boiler and the ease of measuring its performance, together with the comparative uniformity of conditions in the steam-generator, is, probably, quite largely responsible for the practical neglect of the study of the use of fuels in other arts save only on the basis of their thermal value. yet these other arts show quite plainly that a thermal-value basis alone is not sufficient. For example, in burning lime, under ordinary conditions of firing, a cord of wood will do as much work as a ton of coal, though the latter affords more than twice the number of heat-units. Similar results are evidenced in burning brick, in the roasting of certain ores, in reheating billets, and in many other, arts where heat is to be applied over extended areas to fragmental masses of more or less refractory materials. In these arts much is to be gained by a

Jan 1, 1911