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By C. O. Brawner

The advent of larger drilling, excavation, and milling equipment is resulting in a tremendous increase in the scale and annual tonnage of open pit mining. At the present time, open pits up to 3000 ft. deep, and tailings dams and waste dumps up to 600 ft. high are being planned. One of the major problems that projects of this magnitude create is stability. Stability at open pit mining developments must be assessed for tailings dams, waste dumps, and open pit slopes in overburden soil and in rock. Soil mechanics principles are used to assess the stability for the first three. This science was developed by Dr. Karl Terzaghi in the 1920’s, and since that time the theories and principles have been tested and evaluated. This experience has resulted in the development of sound theoretical concepts, workable sampling and testing techniques, and accurate methods of analysis. Typical problems that can be analyzed include: -bearing capacity of soil under dams and waste dumps. - amount of seepage under and through dams. - stability of slopes and determination of safe slope angles for tailings dams, waste dumps, and open pits. - influence of earthquakes on stability. - influence and cost of different excavation and construction techniques. To assist in comparing engineering experience, an international soil classification system has been developed and used for several decades. In addition, many excellent text books are available outlining soil mechanics principles and techniques. A high degree of technology exists in soil mechanics. This, the mining engineer cannot afford to ignore. If soil mechanics principles had been applied, many major failures involving tailings, tailings dams, or waste dumps, such as those at Aberfan, Mufulira, Luanshya, and El Cobre would not have occurred. Tailings dams are planned in Canada that will be up to 600 ft. high. Construction procedures used in the past have paid little attention to the compaction of the shell material or to the influence of earthquakes on stability. This neglect has led to failures. While failures in low dams may not be too serious, for high dams such failures could have catastrophic results. Another major area of concern is the stability of rock slopes. From the standpoint of long

Jan 1, 1971

By Frederik P. Agterberg

This paper deals with frequency distributions in the field of mineral resource evaluation when a grid is superimposed on the study area and metallogenetically significant attributes are coded with respect to the cells of the grid. It is shown that the parameters of a negative binomial distribution for frequency of mineral deposits per cell can be derived from the parameters of a gamma distribution for the coded attributes. It is also shown that an exponential model for spatial correlation of cell values and Matheron's discrete Gaussian model for indirect transfer functions may provide a suitable methodology for relating cell value distribution to cell size.

Jan 1, 1977

By R. A. Turpin

Bethlehem Steel's Research Department is developing a set of computer programs as mine-planning tools for Bethlehem's coal mines. Several of these computer programs have been completed and have been in routine use by Bethlehem Mines personnel since early 1975. The production scheduling and ventilation planning programs have been installed on an interactive time-sharing computer. The use of time sharing allows mines in remote locations to access these planning tools through standard phone lines and low-cost computer terminals. The capabilities of the interactive production scheduling and ventilation planning programs are briefly described. The advantages of implementing them using time sharing are discussed. A case study illustrates some of the benefits that planning based on the use of these programs has already provided.

Jan 1, 1977

By A. Tobey Yu, David A. Kinneberg

As the heart of a copper-producing complex, a smelter converts raw copper concentrates or leach-plant precipitates, or both, into blister copper. A typical smelter feed also contains matte chips, flue dust, flux, and lime. All these materials vary widely in their characteristics, ranging from sub-micron to lumps, from slurry to dust, from abrasive to corrosive, and free-flowing to adhesive. Handling all these materials becomes even more problematic since most of the world's open-pit copper mines are located in a semi-arid zone where rainfall is minimal.

Jan 12, 1976

The United States Civil Service Commission announces open competitive examinations for the positions of valuation engineer, assistant valuation engineer, and valuation aid for the Income-tax Unit of the Internal Revenue Bureau. The duties of these positions will involve the estimating of: (1) The quantity of mineral, oil, and gas or timber; (2) the theoretical and market values of mineral, or oil and gas in place, standing timber, and their products; (3) the value of equipment ordinarily used in discovery, exploitation, and utilization of such natural resources; (4) the cost of development, exploitation, and utilization of such natural resources. The entrance salary for each grade, within the range stated, depending on the qualifications of the appointee, is: Valuation engineer, $3600 to $4800 a year, though in exceptional cases higher salaries may be paid; assistant valuation engineer, $2500 to $3600 a year; valuation aid, $1200 to $2500 a year. Applications for valuation aid must have had a bachelor's degree from a college of recognized standing, graduation from a four years' high-school course, or education equivalent to that required for such graduation, and at least four years' experience in the technical branches of one of the industries mentioned in positions tending to qualify them for the duties outlined above.

Jan 6, 1919

By J. J. Bodmer

ALTHOUGH the similarity between puzzolana, or trass, and blast-furnace slag, as seen by comparison of the analyses, is a well-known fact, blast-furnace slag has not been used commercially as a substitute for those cementing materials. The reason, the writer apprehends, lies in the fact that unless such slag is disintegrated or subdivided by rolls, the process must either be too costly, or the material is not in a fit and proper condition for the purpose. In order to produce a reliable slag cement, the slag must be ground together with the lime into an impalpable powder. The subdivided slag must, therefore, be perfectly dry, and, at the same time, friable. The stronger the hydraulic properties of the lime, the more reliable the slag cement will be, and practice has proved, that the slag from a gray-iron furnace gives the best results. The slag cement which has given the results shown in the annexed table, under pressure tests, was composed of six parts of slag, from a blast-furnace producing No. 3 foundry iron, and one part of lime, of medium hydraulic properties. The above-described class of cement bears storing as long as most Portland cements, and the cheapness of its production is self-evident.

Jan 1, 1874

Today there is unparalleled opportunity for constructive effort in the national mineral economy on the part of the Land-Grant colleges and universities. The matter is too important to be pushed aside. It is inevitable that in the aftermath of World War II, conscientious Americans the country over should want to take stock of national resources. Attention is now centered, as never before, on our mineral potentialities. Opportunities and responsibilities are unparalleled and a condition exists which will not occur for another generation. Mineral industries educators cannot pro- vide the answer without taking stock of its component parts, organizing, planning, and taking action in a real dynamic sense. The services encompassed by the various fields of mineral industries must be utilized to help in the solution of problems provided by the international emergency, the country's needs, the people's needs. Mineral industries colleges have a vital role in technical aid to backward countries through foreign student programs, especially in the Latin Americas.1 By helping them to help themselves develop and utilize their resources to the fullest, we will be helping ourselves. One day they may be a Godsend in a solution of the American demographic problem. They may be prepared to

Jan 1, 1950

Jan 1, 1907

Jan 1, 1907

By Wilbur Nelson

ALL of our accounts of the discovery of copper ore at Ducktown, Tenn., state that the discovery was made in August, 1843, yet it would appear that samples of copper from this district were found by the Spanish explorer, DeSoto, when he wandered into Southern Tennessee, in 1539, in his four years of exploration through the Southern States. The following quotation is taken from his diary: "Towards the north there was a province named Chisca; and that there was a melting of copper, and of another metall of the same colour, save that it was finer, and of a farre more perfect colour, and farre better to the sight, and that they used it not so much, because it was softer. And the selfe same thing was told the governor in Cutifa-Chiqui, where we saw some little hatchets of copper, which were said to have a mixture of gold. But in that part of the country it was not well peopled; and they said there were mountains, which the horses could not passe; and for that cause, the governor would not goe from Cutifa-Chiqui directly quicker." DeSoto sent two of his company to try to find these mines, but after five days' wandering through the mountains they returned, stating that their guides had become lost. Although the Ducktown area may have been known to the ancient Indians, it was not until August, 1843, when a Mr. Lemmons, who was panning for gold on Potato Creek, in the Ducktown basin, found some reddish-brown decomposed rock, which he supposed to be gold, that the copper deposits were actually discovered. His disgust on finding that this yellow metal. was not gold was so great that he did not. try to develop his find. In March, 1847, B. C. Dugger erected an iron forge at this same place, but was unable to work the iron as it contained so much copper that on cooling it would break to pieces. The finding of copper in the iron ore by Mr. Dugger led to further explorations; and in April, of the same year, A. J. Weaver, who was passing through that country, told the people that the black rocks they had dug out were rich copper ore. Mr. Weaver began the first mining in this district.

Jan 10, 1924

By Roswell H. Johnson, W. E. Bernard

To know the rate of declinc of oil wells is very important, yet ordinarily we are prevented from getting this rate because the oil from several wells is put into one or a few tanks as soon as the wells have been connected to the power. The object of doing this is economy of tanks, pipes, labor, and accounting. But we are making a great sacrifice for this small economy. The advantages of the individual records are that we would know better: 1. When the well has ceased to be profitable. 2. When a well has gotten into bad condition. 3. The real record of the yield per acre and the rate of decline of the wells. The lease total is too mixed as to age of the wells for existing records to have much significance. To obtain such individual well records and more accurate logs are the great desiderata of satisfactory management of oil properties. 4. Which wells show the slowest decline—information which is valuable in locating new wells or purchasing adjoining leases. The truth of this statement is evident, when we reflect upon the large number of purchases of producing property. Intelligent appraisal is of the utmost advantage and it is impossible without individual well-pro-

Jan 1, 1918

WHOEVER has occasion to judge tin in its whiteness from the testimony of his eyes alone would surely believe it to be purest silver, or something that comes very near to it in nature. This is even more so when, on handling, it is found to be harder than lead, to which it can be said to have a greater and closer resemblance. But whoever has actual experience with tin knows that none of the other metals is less similar to it than silver. For silver mixes with every metal, as does gold; and they unite together, and the others do likewise; and except for their color they change their natures but little. But this metal tin, wherever it is found, acts like a powerful poison which envenoms and corrupts the others; and it does this not only with large quantities but also with every small amount; indeed just the trace remaining where it has been melted is enough to embrittle silver and gold as well as iron and copper. The greater the quantity of it in these, the greater are its effects. Speculators of natural causes say that this fact arises from its great wateriness, which is very subtle and poorly decocted and almost like that of quicksilver. This wateriness, then, by means of its subtlety which joins itself with metals, imposes itself into that unctuous and viscous material which renders them flexible, and thus deprives them of their toughness

Jan 1, 1942

By P. R. Gage, R. W. Bartlett

SILICIDE coatings on refractory metals are often applied by transporting a silicon halide vapor to a hot metal surface where dissociation or hydrogen reduction occurs. The subsequent chemical reaction to produce the coating requires diffusion of silicon or the refractory metal through the in situ silicide layer. This solid-state diffusion process step is often slower than the vapor-transport step and, therefore, rate controlling. This situation is analogous to the parabolic oxidation of metals in which the oxidation rate is controlled by diffusion through the oxide layer. The purposes of this study were to 1) measure the rate of formation of MoSiz and MoSi2 coatings under conditions such that the silicide diffusion process is rate controlling and lower silicide compounds are not formed and 2) determine by a marker experiment whether silicon or the respective refractory metals are the principal diffusing species in the disilicides.

Jan 1, 1965

By S. Jess Larsen

Modern technology has provided the world with many innovations to improve living standards, ease of job performance, efficiency, and managerial control. While not expected to compete with the computer revolution, Kerr-McGee Coal Corporation has found a way using laser technology to solve one of their haulage problems. Operating successful and profitable surface coal mine facilities in Wyoming's Powder River Basin require economies of scale, flexibility of operation, conscientious cost control, and ever-present innovative effort. Because haulage costs are the major source of expenditure in surface mining, Kerr-McGee recognized early the need for maximum haulage productivity and the economies of scale provided by large haulage trucks. Special conditions that exist in the Powder River Basin coal fields require consideration. The coal thickness (up to 100 feet and more) and varying depths of overburden dictate that a haulage unit with good gradability characteristics be used to avoid undesirable long ramps. Two and often three coal seams are encountered by most mines, which necessitates operating from several coal and parting faces simultaneously. This situation consumes much space, and to minimize the scope of problems, a coal haulage unit with good maneuverability and stability is needed. Finally, the low density of coal (±1500 pounds/loose cubic yard) demands a large volume capacity to utilize truck load carrying capability effectively. These conditions prompted Kerr-McGee to select unitized two-axle bottom dump trucks of the 160-170 ton size for primary coal haulage at its two Gillette-area mines. Use of 170-ton bottom dump trucks at the Clovis Point Mine handles most of the coal haulage, but the truck

Jan 1, 1983

By Adrian E. Ross

DRILLING through caving formations in diamond drill holes at depths greater than 2000 ft has long been a serious problem. These caving formations are normally passed only by casing the hole or by cementing the hole. Casing the hole is possible only when a resulting smaller hole is acceptable. In as much as only a limited number of reductions are economically practical, cementing is frequently considered the only method suitable for solving these problems. Cementing either by pumping a slurry into the hole or by dropping cylinders containing cement has proved satisfactory on holes under 2000 ft. In holes substantially deeper than 2000 ft these methods are not satisfactory, since during the pumping process cement separates out, whereas cylinders usually break before the bottom of the hole is reached. A new procedure, the injector method, apparently solves these problems.* With this method, cement is lowered in the hole in a cylinder, the cement being

Jan 1, 1952

By P. H. Mell

The little village, from which this formation receives its name, is situated on a bluff of the Alabama River, 175 feet above water level. This bluff is a portion of high table land that begins in the western portion of Choctaw and extends through Clarke and Monroe counties. We find points on this ridge more than 100 feet higher than Tuscaloosa, and nearly as high as the Tennessee River at Tuscumbia. Through this the Alabama River cuts its way, exposing a beautiful cross-section of the strata, of which the accompanying sketch may give some idea. The fossils are found about 75 feet below the surface and 100 feet above the level of the river. There are seven distinct strata. 1. The lowest, extending from the water's edge up the bluff 80 feet, is a soft calcareous rock containing about 15 per cent. of carbonate of lime, with occasional specks of mica. In this a few Ostrea, Turritellæ, and Flustræ were found, but so friable as to fall to pieces when handled. 2. Next comes a stratum varying from 2 to 8 feet, consisting of

Jan 1, 1880

By M. J. Shulman

An algorithm used by the US Coast Guard to find lost objects is utilized to optimally allocate exploration efforts during initial stages of an exploration program. Based on classical search theory, the algorithm assumes a target probability distribution function, a detection function, and a cost function. The three functions are analogous to delineating areas of possible mineralization, choice of exploration methods, and exploration budget. Application of the algorithm is shown for a hypothetical target distribution. Using the maximum number of field day available as the cost function, the optimal allocation of effort is shown for different exploration methods, e.g. electromagnetic survey and induced polarization. The adaption of the algorithm for the exploration process is discussed.

Jan 1, 1984

By P. W. Bridgman

THE thesis of this article is that the age of Newton is now coming to a close, and that recent scientific discoveries have in store an even greater revolution in our entire outlook than the revolution effected by the discovery of universal gravitation by Newton. The revolution that now confronts us, arises from the recent discovery of new facts, the only interpretation of which is that our conviction that nature is understandable and subject to law arose from the narrowness of our horizons, and that if we sufficiently extend our range we shall find that nature is intrinsically and in its elements neither understandable nor subject to law. The new experimental facts are in the realm of quantum phenomena. Comparatively little has been written for popular consumption about this new realm which has opened in the last fifteen years. The man in the street has been much more interested in relativity, which to him has seemed extremely interesting and revolutionary. Occasionally, however, there has filtered down to him the news that nearly all the theoretical physicists are occupied with a new order of phenomena which they find very much more exciting and revolutionary than any in the realm of relativity. For after all is said and done, the practical effects of relativity, measured in ,dollars and' cents or in centimeters and grams, are exceedingly small, and require specially de- signed experiments executed by men of the highest skill to show their existence at all. The phenomena with which quantum theory deals, on the other hand, are of the greatest practical importance and involve the simplest aspects of everyday life. For example, before the advent of the quantum theory no one could explain why a tea kettle of water boiling on the stove should not give out enough light in virtue of its temperature to be visible in the dark; the accepted theories of optics demanded that it should be visible, but every burned child knew that it was not.

Jan 1, 1929

Meeting of Nov. 20, 1914.-Charles F. Rand was unanimously elected as the representative of the Institute on the John Fritz Medal Board of Award. E. Gybbon. Spilsbury was unanimously elected to succeed himself in January, 1915, on the Library Board of the United Engineering Society. . The President appointed Messrs. Walter Douglas, Charles E. Mills, and L. D. Ricketts as delegates to the seventeenth National Convention of the American Mining Congress, Phoenix, Ariz., Dec. 7 to 11, 1914. It was voted that the sum of $857.61, or so much of it as may be necessary, be advanced to the Land Fund from the general funds of the Institute, in anticipation of the collection of unpaid installments of subscriptions to the Land Fund; and that the Treasurer be instructed to pay to Andrew Carnegie at the present. time the sum of $2,500 on account of the Land Fund indebtedness.

Jan 1, 1915

By Norman Brown, Victor V. Damiano

ThE present paper proposes a mechanism of dislocation multiplication at internal inclusions or cavities and presents experimental evidence of such sources in zinc. Using an etching technique recently described by Damiano, Tint, and Herman1 to study the three-dimensional aspects of dislocations in bulk zinc crystals, an investigation was made of helically shaped and closed-loop etch patterns found to be associated with inclusions. Crystals containing 0.1 pet Cd and grown from the melt were deformed slightly by bending and then aged at room temperature to precipitate cadmium at the dislocations. The crystals were cleaved along the (0001) plane and then etched with Gilman's2 etch. Crystals were continuously viewed on the (0001) plane while the etching was in progress and numerous helical and closed-loops etch patterns were continuously recorded as shown in the sequences printed directly from the cine film in Fig. l(a) and (6). These etch patterns are not to be confused with the etch patterns previously reported by Damiano and Herman3 which revealed dissolution spirals on the (0001) plane of high-purity zinc crystals. In the present case, precipitates arranged in the form of closed loops or helicies are progressively uncovered by etching after suitable aging of cadmium doped zinc crystals. Viewed with dark-field illumination as shown in Fig. 2, portions of a helical figure and subboundaries were revealed simultaneously. Continuous viewing while the etching was in progress revealed in Fig. 1(b) that the short line segments observed on single photomicrographs were in fact continuous and described a helix which had its terminus at an inclusion. The observations suggested that a dislocation once nucleated at the interface between the inclusion and matrix may act in such a way as to produce ad-

Jan 1, 1964