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By Walter E. Heinrichs

The following is a condensed version of an open letter addressed to Bil Gilbert of Sports Illustrated: Your article, "When a Law Fights a Law, Sports Illustrated. April 26, 1971, betrays considerable unfamiliarity with the subjects of ecology, social science, mining law and history. In a magazine as widely circulated as Sports Illustrated, an article of such a slanted nature misleads the general public.

Jan 1, 1971

Jan 1, 1969

By George E. Erdman

Gouverneur Talc Co. had sought an effective means of depicting its mine at Balmat, N. Y. since it commenced operations in 1947. After considerable research the engineering department settled on the idea of a model made of plexiglas at a scale of 1 in. to 50 ft. The solid portion of this model represents the actual underground excavations. Talc is mined from two metamorphic tremolite-talc orebodies which are part of a complex fold system in this region. In the mine, stopes are laid out in panels and developed into openings 50 ft wide, 10 to 80 ft high, and perhaps 200 ft in length. Pillars usually approximate 30 ft in width. All present mining operations are contained within a block 2000 ft long, 1700 ft wide, and 1500 ft thick.

Jan 11, 1960

By S. A. Braley

THE first commercial production of bituminous coal in the United States was in 1820, and formation of acid in the areas from which the coal was removed began at that time. Thus it is 130 years since the development of mine acid began. The coal operator has had to deal with the acid water produced in his mines, and his losses from corrosion of pumps and equipment have been tremendous. Other industries and the public have been forced to spend large amounts for their water requirements because of the acid discharge from the mines. There are many contradictions in the literature on this subject probably because of variations in the analytical procedures followed and differences in the methods of calculation and reporting. The opinions previously expressed may be summarized as follows:

Jan 8, 1951

By Arthur R. MacPherson

The development of a simple method to predict the autogenous grinding possibilities of new ore deposits is attained. This method employs a 45-cm (18-in.) dry grinding Aerofall mill to grind small quantities of core or crushed samples in the top size range of 2 to 5 cm (1 to 2 in.). An extensive program has been carried out to correlate the data obtained in the 45-cm (18- in.) test mill with the actual results obtained in large commercial plants or autogenous test plants. Enough evidence now exists from these correlation programs that the 45-cm (18-in.) mill can be used to grind small samples from a new deposit and correctly predict the autogenous grinding mill requirements of a commercial plant to treat this ore.

Jan 1, 1978

By John J. Schanz

THE highly publicized shortage of students enrolled in engineering curricula has brought about a rapid increase in the enrollment in engineering schools in many parts of the country. Though most of the various curricula in the mineral industries field have participated in this increase, the experience at Pennsylvania State University has been that the nonmineral types of engineering have been increasing at a much more rapid rate than those in the College of Mineral Industries. [ ] It has been a matter of some concern to the staff of the College of Mineral Industries that enrollment in the curricula of the school has not been increasing at a rate commensurate with that experienced in the College of Engineering. If the lack of trained young graduates for our vital mineral industries is to be overcome, this situation must be remedied.

Jan 8, 1954

By Koehler S. Stout

At today's mineral prices, unproductive or low productive work in any underground mine must be kept at a minimum to insure a profit. Improper level and raise spacing can be one of the contributing factors to high production costs, and little can be done to reduce these costs after the spacing interval has been chosen. The objective in selecting level spacing is to find the most desirable interval which produces ore at the least cost per ton while still operating within the highest margins of safety and efficiency to the workmen. In addition, maximum possible recovery of ore under the conditions must be attained.

Jan 11, 1962

New York State Museum, Albany, N. Y. D H. Newland, State Geologist. A complete list of publications or the latest lists of available publications will be sent upon application. A series of Bulletins on The Mining and Quarry Industry of New York are available as follows: Bulletin 51 (1910), 15 cents; 161 (1911), 20 cents; 166 (1912), 20 cents, 174 (1913), 20 cents; 190 (1915), 15 cents; 277 (1925-26), 50 cents; 295 (1927-1929), 40 cents. Another series discusses the Geology of the State by Quad¬rangles, available as follows: Bulletin 153, Broadalbin Quad (1911), 25 cents; 154, Sche¬nectady Quad. (1911), 20 cents, 170, North Creek Quad . (1914)

Jan 1, 1933

By Walter S. Landis

The earliest example of attempting to form finely-divided materials into larger masses for better adaptation to commercial use mas probably the briquetting of peat and lignite-waste at Paris by the use of a clay binder. It was from this attempt that our word briquette has arisen (Fr. la brique), the formed masses being shaped similar to ordinary bricks. This term does not, however, lend itself to the many shapes of such formed material as are now being produced, as few of them, aside from some of the European brown-coal products, bear any resemblance to the shape of that well-known article. The

Jan 1, 1913

By Robert A. Bauer

This study showed that diametral point-load testing performed parallel to the bedding planes of highly anisotropic sedimentary rocks produced inconsistent results that cannot be used to accurately estimate uniaxial compressive strength. Axial point-load values from tests performed normal to bedding planes and evaluated by the T500 index produce good correlations with the uniaxial compressive strength values obtained for five different rock types. A strong correlation also existed between the moisture content and the uniaxial compressive strength of the tested lithologies. A combination of axial point-load and moisture content indices produces the best correlation with the uniaxial compressive strength test results.

Jan 1, 1984

By Harry Bapty

LONGHOLE drilling with a heavy type percussion Leyner drill, jointed steel rods, and a tungsten carbide insert bit was investigated while drilling and working a quartz barite brecciated rock. Procedure and practice were developed and its suitability for tackling pillar and sill recovery proven and extended to regular stoping at Torbrit. Torbrit, as the name implies, is a contraction of the Toric property and the Britannia Mining & Smelting Co. Ltd., the former owners. This silver property, with minor amounts of lead, zinc, and rarer sulphides of little or no economic value, was discovered in 1916 from an outcrop in the Kitsault River, 18 miles north of Alice Arm Post Office, in the Portland Canal Mining District, B. C.

Jan 11, 1954

By P Shenon

THE Elk City district is in north-central Idaho about 60 miles east of Grangeville and near the headwaters of the South Fork of the Clearwater River (Fig. 1). At the height of its boom in the early sixties, Elk City had a population of more than 2000 people.1 Published estimates of the placer production from the district range from $10,000,000 to $18,500,000. Although the first quartz-vein location was made as early as 1870, very little gold was extracted from quartz ores until after the completion of the American Eagle mill in 1902. Between 1902 and 1932 a total of from $750,000 to $1,000,000 was taken from about six properties.

Jan 1, 1934

By Reed S. C. Rogers, Robin P. Gardner, Kuruvilla Verghese

The development and use of short-lived radioactive tracer methods for the onstream determination of residence time distributions in large-scale ball mills is described. Tests are reported on a pilot-plant ball mill with 0.43 m diameter and 0.86 m length and on an industrial mill with 1.83 m diameter and 2.74 m length. Tests with different tracer feed sizes indicate that the residence time distributions on both mills are independent of charge particle size. Similar tests are planned for a large ball mill of 4.57 m diameter and 9.30 m length. No safety problems were encountered in these tests and none are anticipated in tests of the larger mill.

Jan 1, 1981

By T. A. Rickard

In " The Genesis of Certain Auriferous Lodes "* Dr. Don makes a reference to a curious vein-formation known as the "Indicator," which characterizes a portion of the Ballarat mining district,, in Victoria, Australia. During 1890 and again in 1898 I had an opportunity of making a few notes, which, although somewhat belated,t may be worth adding to the observations recorded in the Transactions of the Institute. The country of the Ballarat gold-field consists of the Lower Silurian slates and sandstones, which also enclose the reefs of Bendigo; but it is noteworthy that the successive anticlinal folds, and accompanying saddles of quartz, which distinguish Bendigo are not characteristic of Ballarat, the geological structure of which presents greater complexity. That part of the district known as Ballarat East became famous early in its history on account of the large nuggets which were found in the alluvium, and subsequently it became further known because of a peculiar persistent black seam, traversing the bed-rock underlying the alluvial deposits, which was found to be associated with rich bunches of gold-ore, not only in the gravel that capped it at the surface but also in the quartz-veins which crossed it underground. The name of " Indicator " was early given. In 1871 Mr. Morgan Llewellyn directed attention to it as influencing the distribution of the gold. In the government quarterly report for December, 1888,

Jan 1, 1901

By S. M. Bishoff

The disturbance of surface land to support the underground mining of coal requires several hundred acres to produce easily in excess of $1 billion in sales at a moderately sized mine over 20-30 years. Due to the recent influx of environmental legislation, these surface operations must now undergo complete reclamation upon permanent cessation of production. This reclamation procedure has become so complex that the cost of reclamation must be a major consideration in the design of a new mine. This presentation will discuss these costs as they may be methodically evaluated and surcharged as a percentage of the product price. When placed in the proper, logical perspective, it is anticipated that the obstacles involved in this process may be minimized.

Jan 1, 1985

H. H. Hill.—I believe that as petroleum engineers you are all more or less interested in geophysical prospecting. A large number of the papers that have been written on that subject are too detailed or too much involved to be of much value to a person who is not familiar with the subject, so I suggested to Mr. Fohs that he might bring us something that we could all understand. As I take it, we are interested in learning something about the different methods, the places where they have been used, their limitations and in general whether they have given satisfaction in locating oil deposits. F. J. Fohs, New York, N. Y.—I will briefly summarize some of the results as I Bee them from my practical contacts with them and my discussion of the subject with some of the more important rnen both in this country and Europe. Geophysical Methods 1. Seismographs: A. 1. Sonic refracting seismographs of Karcher, McCullom and Reiber. For rapid reconnaissance and also for detail—perhaps, the best type of instrument. 2. Mechanical refracting seismographs of the Weichert-Mintrop type. B. I. Sonic seismographs using reflected sound from contacts of sufficiently unlike beds where latter are thick enough, being used for detail of both salt domes and ordinary structures where a good reflecting key bed occurs. 2. Torsion Balances: Made in three sizes with greater portability and loss of but 20 per cent. in medium size and loss of 40 per cent. efficiency in smallest size. A. Used to best advantage in detailing salt domes, in noting anomalies of deep-seated structures of the Edgerly, La., type (but not always certain here and dependent on interpretation which involves both experience and the human equation to a large degree). R. Used to advantage in mapping faults where a lime or other denser bed occurs upthrown, and the topographic irregularities are not too involved. C. Of use where buried granite plugs and buried-hill structures occur as in the Western Texas fields. D. Believed of little use for other types of structure. 3. Magnetometers or Variometers: Now built horizontal and vertical with declinometer combined in one instrument. A. Practical in mapping granite or basic igneous rock plugs and intrusions, or of detritus therefrom. Adams has recently demonstrated definite results in mapping the well known Panhandle arch.

Jan 1, 1928

By R. L. Sandefur

Professor Kim's excellent review article1 on ultimate pit planning contains a statement of the apparently widely held but incorrect belief that "kriging provides information on the confidence limits around the estimate which no other extension technique is capable of supplying." If a geostatistical approach is valid, there are several good reasons for using kriging but uniquely provided confidence limits is not among them. If kriging is possible, then confidence limits can be calculated for any other linear estimate.

Jan 6, 1979

By J. Redstone, A. R. Laplante

Sidbec-Normines operates six large iron ore concentrate regrinding mills in parallel and open circuit at its Port-Cartier pelletizing plant. Grinding kinetics in these mills were characterized for slurry densities varying between 70 and 89% solids, using a lumped parameter size discrete model. Optimum grinding conditions were encountered at 83.5 to 84% solids. Higher densities decreased the normalized selection function and increased slurry short-circuiting, yielding a sharply coarser mill discharge. At lower slurry densities, the normalized selection function decreased and the mill discharge coarsened slightly. The grinding kinetic model predicted particle size distributions within the mill. These were found to vary significantly from the feed to the discharge end. This is likely to cause nonlinear breakage kinetics.

Jan 1, 1985

By Joseph Kittredge

AT the time this matter first came up in 1912, the National Malleable and Steel Castings Co. had seven basic-bottom open-hearth furnaces in its plant at Sharon, Pa., using fuel oil, then costing about 2 ½ ¢ per gallon. The fuel was satisfactory but its cost fluctuated widely, therefore the use of pulverized coal, which had been successful in the cement industry and in some metallurgical furnaces, was suggested. After a thorough investigation, and an actual trial on one of the open-hearth furnaces, to be certain that the siliceous ash in the coal would not seriously affect the basic slags, the management of this company approved its adoption and a complete installation was started. The conclusion had been reached that the success of the operation depended on pulveriz-ing the coal to greater fineness than had thus far been accomplished, and all equipment was chosen with this in mind. A coal drier was deemed essential, and one of ample capacity and efficiency was selected, which has done all that was expected of it, working without failure and with very small maintenance cost, and is still in operation.

Jan 1, 1939

By D. T. MacRoberts

Tins paper embodies the results of theoretical studies concerning gas reservoirs, especially the effect of drilling programs of various intensities upon pressure depletion and ultimate recoveries. The primary objective has been to determine the net quantity of recoverable gas that could be obtained as a result of each additional well, in comparison with the gas that might be secured from a single well ideally placed with respect to both acreage and geological structure. No method is yet known whereby the relative merits of intensive and sparse drilling can be compared experimentally; a reservoir must either be drilled closely or developed with wide spacing, but both programs cannot be conducted simultane-ously. Hence, the analytical method seems to be the only approach to the problem. While the present state of our theoretical knowledge does not offer a precise solution to the problem of gas flow in sand bodies, it takes such appropriate cognizance of the limitations of the methods used as to restrict any answer obtained to the realm of engineering accuracy. In solving the problem for the average gas field, it was found that practically the same answers resulted as to pressure distribution, regardless of the size of the drainage radius, even though the latter was assumed to vary from a few feet as a minimum to that of the entire reservoir as a maximum. Such limits represent extreme possibilities; therefore, the practical conditions that are associated with normal development programs, in which wells are placed in the center of tracts varying in size from 40 to 640 acres, will of necessity result in less extreme variations than those indicated in the tables accompanying this paper. Stated more concisely, the amount of gas unrecovered at abandonment (of the particular field used for illustrative purposes) will lie somewhere between 4.6 and 6 per cent of the total original content, no matter how intensively the field is drilled.

Jan 1, 1938