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By Leigh J. Wardle

SUMMARY This paper describes a numerical method for calculating the three- dimensional stresses and displacements induced by tabular excavations in a rock mass consisting of parallel layers of distinct material properties. The method is based on the superposition of numerical solutions for elementary displacement discontinuities in a parallel layered rock mass. The method can be used to analyse complicated excavation layouts such as those encountered in room-and-pillar or longwall mining. The method can automatically take into account the effect of the earth's surface. The method offers an economic and efficient solution to stress analysis problems which cannot be adequately modelled using two- dimensional methods and for which the expense of three-dimensional finite element or general boundary element analysis cannot be justified. INTRODUCTION Underground mining often takes place in tabular or lenticular orebodies. In many cases, for example room-and-pillar and longwall mining, the excavation geometry cannot be adequately modelled by two- dimensional methods of analysis. In these cases resort must be made to three-dimensional methods of analysis. Although in principle three-dimensional finite element models can be used for these geometries, cost limitations have restricted their application to a small number of cases. For example, room-and-pillar systems of regular pattern have been analysed by numerically modelling

Jan 1, 1984

By J. O. Whiteley

IT is difficult to give a refining outline that may be followed for any and all combinations of the platinum metals; different combinations require different methods of attack. This paper does not pretend to go into all of the reactions of the metals of the platinum group, but will outline the commercial refining of platinum scrap. TYPICAL PLATINUM SCRAP As a concrete case, let us take 100 oz. of miscellaneous scrap, made up of jewelry scrap, dental scrap and laboratory ware. This lot will contain some platinum, palladium, iridium, ruthenium, rhodium, gold, silver and copper. The first problem is to get all of the metals in solution. If the scrap is principally platinum, palladium and gold, a treatment with aqua regia is the course to pursue; but if the scrap contains alloys high in iridium or ruthenium, aqua regia will act too slowly. In the case in hand, we are going to presume that we have scrap high in iridium and ruthenium, and proceed accordingly.

Jan 1, 1928

By Theodore H. Eyde

The porphyry-copper province of southwestern United States and northern Mexico constitutes the largest copper-producing region in the world. More than 20 deposits discovered since World War II are being exploited or in the process of exploration and development. Because of the remarkable success in discovering new deposits, exploration activity continues at a very high rate and deeper targets are explored each year. Exploration programs for deeply buried porphyry-copper deposits require a reevaluation of the conventional exploration techniques. Though surface induced-polarization techniques have about reached their practical detection limit, aeromagnetics will play an increasing role in the exploration activity as will downhole logging tools. In addition to a valid geological concept, any successful exploration program for porphyry-copper deposits in the southwest must have two other essential ingredients: money and guts. Unfortunately many exploration programs in the southwest are underfunded and doomed to failure. Future exploration will demand more joint venturing in which larger and more expensive exploration programs can be successfully funded by groups of companies or syndicates.

Jan 1, 1975

By R. D. Russell, R. M. Farquhar

ISOTOPIC tracers have become an important aid in following the progress of chemical processes in the laboratory. It has recently been found possible to utilize a system of naturally existing isotopic tracers to obtain information about the geo- logical history of lead ores. Common lead, such as is found in lead deposits, is a mixture of four stable isotopes having atomic weights 204, 206, 207, and 208. Of these, the last three are identical with the lead isotopes produced as stable end products of the radioactive decays of uranium and thorium: the first, lead-204, is not known to be produced on the surface of the earth by any process. Since uranium and thorium occur in the surface regions of the earth in amounts comparable with lead, and since the half-lives of uranium and thorium isotopes are of the same order as the age of the earth, they produce the radiogenic lead isotopes in amounts com- parable to the amount of nonradiogenic lead present. Every significant exposure of a sample of lead to uranium and thorium will therefore lead to the permanent alteration of the lead isotope ratios in that sample.

Jan 5, 1957

By E. J. Wasp, T. C. Aude, F. B. Raymer

The following paper deals with technical aspects of terminal facilities for western coal pipelines. The information is taken from the Ohio and Black Mesa pipelines and the proposed one in Wyoming. This paper first discusses the feed terminal, the product that it must produce, and the reasons for coal cleaning. Then in the delivery terminal section, the various methods of dewatering the coal and some recent innovative ideas on bunkering the dewatered product and storing the dewatered coal in large outdoor piles are discussed.

Jan 1, 1979

By B. C. Scott, A. Baker

The Pitch mine of Pinnacle Exploration, Inc. is in the Marshall Pass district, thirty miles east of Gunnison, Colorado. This is a new mining district, having come into existence as recently as 1955, when uranium mineralization was discovered rather late in the days of the uranium boom. There have been three other mines in the district, all of them now inactive. Two of these produced a few hundred tons of very high-grade uranium ore, and the third, Pinnacle's Little Indian 36 mine, produced a few thou- sand tons of lower grade ore. Pinnacle was one of the first companies in the district, and was able to acquire a large acreage. The first two years of exploration were essentially wasted in looking for Plateau-type deposits in a mineralized sandstone bed, but this "wasted" work produced two specific items that paid off. One was an ore-grade outcrop that ultimately became the Little Indian 36 mine, and the other was a boulder of very high-grade uranium ore that eventually led to the discovery of the Pitch mine; however, the actual source of the boulder still has not been found.

Jan 5, 1961

By Terry E. Perkins, Len Marnewecke

Installation of a relatively simple, low-cost analog mill control system at Amax Lead Co. of Missouri's Buick concentrator has paid off handsomely. The system, which provides the capability of handling mill circuit upsets and ore changes while maintaining a desired particle size, is expected to generate annually a return on investment of several times its capital cost. In addition, the system stresses simplicity of field instrumentation and control strategy, leading to better operator acceptance and understanding, and its capital cost makes it very attractive for the specific installation when compared to more complex schemes using mass flow measurement and computers for calculating circulating load to infer particle size. This system has the advantage of utilizing an actual measurement for control, rather than a difficult-to-maintain inferred value.

Jan 2, 1978

By Steven Cordiviola, Richard Sergeant

The Kentucky Geological Survey(KGS) was established in 1854 as the official geologic research organization in the Commonwealth. Since that time the Survey has performed basic research in a number of geologic areas such as energy, applied geology, mineral resources, geologic mapping, and hydrogeology. Because of coal's importance to Kentucky, a significant part of the geologic data collected by the KGS is coal related. Coal-related data also occur in a variety of other KGS data sets such as the petroleum and water data files. To adequately respond to coal-related inquiries, the KGS maintains an inter- active, on-line data base in which various types of geologic and hydrologic information can be easily stored, retrieved, and manipulated. The KGS will continue to expand and update this data base through ongoing research, and by cooperating with the Kentucky Natural Resources and Environmental Protection Cabinet, Kentucky Department of Mines and Minerals, U. S. Geological Survey, and University of Kentucky Institute for Mining and Minerals Research. Data in this comprehensive system is available to State, Federal, and local governments; industry; researchers; and the general public. These data facilitate coal exploration, mine planning and permitting, coal production, and research activities in the Commonwealth of Kentucky.

Jan 1, 1983

By A. M. Gaudin, T. P. Meloy

This paper presents the theoretical derivation of the distribution equation for single fracture. The equation is shown to accord with experiment. Several empirical size-distribution equations have been proposed to describe the size of broken materials. Among them are the Gaudin-Schuhmann equation and the Rosin-Rammler equation.3*4 The Gaudin-Schuhmann equation relates the relative fraction of undersize to relative size —. In this relationship Mo is the total weight of crushed sample, M(x) the weight of undersize contained, x the size considered, K a quantity called the size modulus, which together with the slope parameter, m, characterizes the product. The slope parameter is usually close to unity. The Rosin-Rammler equation relates the same relative fraction of undersize to the relative size modulus by an equation of different form In this relationship, e is the base of natural logarithms. In the fine size-range when m is unity both equations give Gilvarry and Berstrom have sought a size distribution equation having a sound theoretical basis. They have come to an equation taking into account the effect of volume, surface and edge flaws in fragmentation. If the effect of the volume and surface flaws is neglected, the equation taking only edge flaws into account has the form of the Rosin-Rammler equation. In the present paper, a theoretical size-distribution

Jan 1, 1962

By V. R. Garflas, J. W. Ristori, R. V. Whetshel

Preliminary estimates indicate that world consumption of petroleum products and related fuels in 1937 shattered previous records with a figure of 1,920,000,000 bbl.; that is, 124,000,000 bbl. more than the 1936 total. The writers, as in previous years, have been unable to account for all the available supply in 1937. This "unaccounted-for" supply, which formerly was thought to go largely into storage in foreign countries, was close to 53,000,000 bbl. in 1933; 93,000,000 in 1934; 111,000,000 in 1935; 75,000,000 in 1936 and 148,000,000 in 1937. As this discrepancy between supply and demand continued year after year, it became evident that other reasons than additional foreign stocks were responsible for it. It can now be stated that the "unaccounted-for" supply (see Table 1) goes to take care of: (1) consumption of petroleum products and related fuels for military purposes, the figures of which have been and are kept confidential by foreign countries, (2) additions to stocks to be consumed for military and nonmilitary purposes in foreign countries on which likewise no information is available, (3) errors incurred in the conversion of figures of production of crude oil, its products and related fuels from "weight" units, as used in Russia, for instance, to their American or "volume" equivalents and vice versa, and (4) to the lack of reliable statistics on production and consumption, particularly from Russia, the

Jan 1, 1938

By Paul H. Johnson

Chemical mining may be defined as the use of chemicals in extracting metal values from in situ broken or unbroken ores within a mine. The present means for the generation and regeneration of sulfuric acid or sulfuric-ferric sulfate solutions are inadequate for most applications. This report describes a pressure oxidation process for the generation and regeneration of these solutions from pyrites and spent iron sulfate leach liquors. While recent mining developments such as solution injection, caving, and conventional and nuclear blasting, have provided new and better means for the per-colation of leach solutions through rock masses, little has been done to reduce cost and improve the quality of the leach solutions that are required. A leach solution for chemical mining should meet certain requirements. It should be 1) inexpensive on either a small or large tonnage basis, 2) capable of selectively leaching the desired ore minerals contained in a particular ore, 3) of the proper strength or quality to do the job of leaching in an underground environment and 4) amendable to simple and inexpensive metal recovery steps. It is also important that the capital investment be low for the solution generation and; or regeneration plant.

Jan 8, 1965

By K. P. Wang, Virgil L. Barr

The U.S. Minerals Attaché Program, similar to the scientific and technical attache programs of other industrialized nations, is designed specifically to keep surveillance on significant worldwide developments in minerals, metals, and fuels. Knowledge of international minerals developments is essential for both domestic planning and conduct of foreign affairs. CONTROLLED BY DEPT. OF STATE Ten minerals specialists-eight minerals attaches and two petroleum attachés-man this far-flung, worldwide program for the U.S. Government as best they can. Minerals attach& also handle oil, in posts lacking petroleum attaché. The legislative authority for the Minerals Attaché Program is the Foreign Service Act of 1946 and succeeding amendments and Presidential Executive Orders. Therefore, this program is controlled by the Department of State. Interior (representing the Bureau of Mines) and State collaborate in policy formation and direction by means of a "memorandum of agreement" which covers establishment of posts, selection of officers, contents of reports, and supplemental training. State also has about half a dozen nonspecialist officers to complement the work of the minerals and petroleum attaché. It is not the intention here to evaluate the administrative arrangements of this program but rather to describe it and to provide examples of the important job it is doing.

Jan 11, 1965

By Wilson D. Michell

THE Magma copper vein trends east-west, dips 70° south, and cuts through a 6000-ft thickness of limestones, quartzites, shale, diabase, and schist. The vein is itself a fault with -a horizontal offset of 500 ft on the formation contacts in the two walls. There are two principal faults of large displacement and numerous smaller steep and flat faults that complicate the prediction of ore occurrence. A study of the geology, its systematic recording to facilitate ready reference, and graphic methods of interpretation of mineralization have aided the exploration, development, and mining of the ore. In making predictions of the distribution of mineable ore bodies and their shape in critical areas, studies are made of "mineralization contours" and "mineralization trends," which are developed on a longitudinal section of the vein from variations in the concentration of the combined base metal content as shown by assays of available openings in the mine.

Jan 1, 1947

By Larsen. Edward P.

The principle of "bed blending" in the agglomeration of materials is about 56 years old, but de- spite all education via technical papers, operating reports and results from functioning installations, the concepts of blending are still somewhat vague. Confusion exists between "mixing", "blending," and the basic role of each. The terms "blending" and mixing" are often used interchangeably, yet they describe two different processes. As properly understood and applied, a blend is a combination of different varieties of material which produces a desired quality, or the mingling of different elements to form a harmonious whole. In other words, blending is a process of combining granular materials by mechanical means, wherein the final product, or a portion thereof, must contain an exact proportional amount of every one of the several different materials which contributed to the mass and wherein all particles are so thoroughly intermingled with each other as to have lost their individual identities and become a part of the whole so that when a portion of the blend is taken at any time it will be substantially identical, chemically and physically, to any other portion taken throughout.

Jan 1, 1962

The regular activities of the Insti¬tute are financed mainly by income derived from members' dues, from advertising in MINING AND METALLURGY, and from the sale of publications to the public. In addition, collateral activities and special projects are financed each year by means of income from endowed funds controlled and administered by the Institute. In the aggregate, the principal sums of these endowments amount to more than $530,000. An active effort is being made to in¬crease the endowment funds of the Institute through a standing committee, of which H. T. Hamilton is chairman, and of which the other members are: W. H. Aldridge, George D. Barron, Cleveland E. Dodge, D. C. Jackling, Henry Krumb and J. V. W. Reynders. This committee feels that there exists a tremendous opportunity for the Institute to be of ever-growing service to the public, to the mineral industries, and to the profession. It welcomes suggestions as to names of men of means who are vitally interested in the mineral industries, and to whom the opportunity to make a contribution or bequest might appeal favorably if presented in the proper light by the committee.

Jan 1, 1942

By William Glenn

Almost beyond doubt, the most important contribution to the assaying of copper yet made, is that of Mr. Eustis (Bans., xi., 120) on the " Comparison of Various Methods of Copper Analysis," which indicates in a manner for which the assayer cannot but feel grateful, how a copper sample ought to be treated from the moment it enters the laboratory until the copper is finally weighed. Admitting, as the present writer is inclined to do, that this paper establishes, as the official standard, the method of electrolysis, we may note as one of the few details which it does not finally fix, the kind of battery most desirable for precipitating the copper upon platinum. In this respect each assayer appears to be a law unto himself, while all feel more or less " shaky " as to the results. Classsen seems to suggest a remedy when he directs the measuring of the -gases liberated by the battery employed. But, in fact, that measure is not a constant in the Bunsen elements which he prescribes for copper determination. Furthermore, measuring gases necessitates more machinery and labor than the average assayer has a stomach for. It is, however, but just to Classen, to whom we owe so much, to reeall that he wrote more especially for students in the schools.

Jan 1, 1889

By C Gunther

In deposits in which the secondary zones are well defined a layer of rich oxidized ore is frequently found immediately to overlie the enriched sulphides, from which it is derived by direct oxidation in place. In deposits that contain oxidizing precipitants particles and masses of residual oxidized ore are likely to be scattered through the leached zone, having been precipitated during migration before reaching the zone of enrichment. This precipitation hinders secondary enrichment and in extreme cases prevents the formation of such concentrations. Residual ores are precipitated by various reagents. Carbonates are formed through the action of the carbonic acid contained in surface waters, and also directly through the replacement of calcite, especially where the containing rock is limestone. Native metals, such as copper, gold, and silver, are formed by the action of reducing agents, among which organic matter and ferrous sulphate are prominent. Kaolin, gouge, and certain shales occasionally act as powerful precipitants through adsorption. Silver is often found as residual chloride, formed through precipitation by the chlorine contained in surface waters. Residual ores are often the result of incomplete solution, the relatively insoluble minerals being left behind during the migration of associated metals; incomplete oxidation and solution often leave residual masses of unaltered, or partly altered, sulphides in the oxidized zone. Such residual particles or masses have commonly been enriched by additions from circulating, metal-bearing solutions. During oxidation under conditions that permit reprecipitation, such as the oxidation of sulphide deposits in limestone, a scab

Jan 1, 1932

By T. Egleston

Although the success of metallurgical operations depends so largely on the possibility of finding proper refractory materials, which enter so prominently into the cost of their operations, it can hardly be said that our knowledge of them is in a very satisfactory condition, or even that we know very much about them, beyond a few facts which have been gathered through their use. Experience, as a general thing, is an excellent master, but the requirements of

At its meeting on February 21, 1933, the Board of Directors passed the following resolution defining and expressing the policy of the Institute with respect to official participation or action in controversial matters: WHEREAS, the Board of Directors at its last meeting passed the following resolution: "The Board of Directors, having been appealed to by several Local Sections for advice concerning the attitude and policy of the Institute relating to the endorsement of candidates for public office, the following statement of policy is formulated;

Jan 1, 1932

Jan 1, 1932