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SUMPEARY OF CURRENT PRACTICES History The outcrop and surrounding area of Comincots Sullivan Mine was originally mined by small open cuts on surface and small open stopes underground to which shafts and adits were driven for access. When it was established that a commercial grade of ore was available, an adit was driven on the 4600 level (feet above sea level), and OM was extracted by larger scale open stoping leaving supporting pillars where necessary. After the depth of the ore body was proven to the 3900 level and an adit driven at this level, many miles of drifts, crosscuts, raises and sublevels were driven for the extraction of the ore above this level. Larger open stopea were extended from this development. The mining method was, and to a very limited degree still is, a benching method. Due to the strong hanging wall in this area of the mine, stopes with a width of 100 feet or more were opened. In 1931, because the orebody was proven to extend below the 3900 level, a winze was sunk from the 3900 level to the 3350 level. From this winze three intermediate levels were opened. Following a plan of development well in advance of production requirements, further sinking was done by winzes and eventually a large shaft was raised to surface. Prior to 1958 the 2850 level was bottom which since that time has been extended to the 2500 level. Open stopes were developed and mined as this area was opened up.

Jan 1, 1970

By A. B. Young

In the original design of the flue system, the flues from the roasters delivered their gases to a large brick dust chamber which discharged into another flue with stack connection, as shown in Fig. 1. The treater is so situated that the gases are taken by it directly from the chamber and discharged again into the flue. The complete installation comprises two treater units, only one of which has been installed at present. The treater is essentially a flue 1.0 ft. high, 12 ft. wide, and 61 ft. long. (3 by 3.6 by 18.5 m.). Suspended inside, vertically and running lengthwise, are four banks of No. 20 corrugated iron plates; each bank is 10 ft. long, making an effective treater length of 40 ft. The spacing from center to center of the rows of plat,es is 9 1/8 in. (23 cm.) giving six-

Jan 1, 1921

By Robert L. Schuster, James A. Doolittle, Ronald L. Sack

The effect of the height of a retaining-wall-supported berm on the slope stability of an idealized mine-tailings dam was investigated. The material in the dam was idealized as a two-layered system with the phreatic surface delineating the boundary between the layers. In each layer the tailings were assumed to be homogeneous and isotropic. The effect of variation in height of the berm was examined for tailings dams with three different, commonly occurring slopes. The stresses and displacements were obtained using the finite element method. An incremental analysis technique was employed to simulate sequential construction of both the tailings dam and the retaining-wall-supported berm. A one-dimensional element was used to represent all interfaces and discontinuities in the finite element model. Assuming a hyperbolic model, the nonlinear stress-strain relationship for the tailings was approximated using the method of successive increments. The stresses obtained in the finite element analyses were used in conventional slope stability analyses assuming circular failure surfaces. The results of the study show that the use of a retaining-wall-supported berm is an effective means of improving the stability of a tailings dam. This increased stability is greater for dams with steeper slopes. In addition, the increase in factor of safety is particularly notable for berm heights less than 25% of the height of the dam.

Jan 1, 1975

By Robert Sisselman

Saving time and energy at Consolidation Coal Co.'s Rowland mine is realized by exploiting its coal deposits via three mining methods. Surface, auger and underground techniques are uniquely combined with specialized transport vehicles to coax the coal from seams unduly protected by topography and lithology. These factors account for what is believed to be the swiftest and most economical means of working the Beckley, W. Va., property.

Jan 1, 1970

By E. A. Wieselmann

This chapter presents a successful approach for achieving mine entry stability at the Cane Creek potash mine by the utilization of closure measurements. The mine is located in southeastern Utah (Fig. l). Mining is being conducted at depths in excess of 3000 ft under structurally complex geologic conditions typical of the Paradox salt basin. The closure measurement systems described have definite application for determining relative entry stability in other nonelastic rocks which are similar in behavior to potash. Similar types of closure measurements have been taken in various underground openings throughout the United States, Canada, arid Europe. Application of this closure data has previously met with varying degrees of success as a tool for design of under- ground openings in both elastic and nonelastic media.1-32 Closure measurements can be made easily and economically and they provide a practical solutiori to a practical problem. They are in-situ measurements which do not necessarily require laboratory correlation. Simple closure measurements have special significance in potash because "steady-state" ' closure rate, or creep, of the entries is measured. These closure rates can be utilized because nonelastic media such as potash will never achieve absolute stability around a mine entry. The potash will tend to creep or deform until all entries are closed and the overburden stress is redistributed over what was previously the mine area. The time for this ultimate effect to occur is dependent on a number of mining and geologic variables. Percentage of mine extraction, mining

Jan 1, 1972

By W. B. Daly

THE sampling and estimating of, the orebodies in the mines of the Anaconda Copper Mining Co., at Butte, have been made a part of the work of the geological department. The wisdom of this assignment is apparent, considering the organization of that department, the nature of, its records, and the scope of its regular work. In the first place, the district is divided into units of two or three mines each and a geologist is assigned to each group. His trips to all the working places are frequent and he follows the mining operations closely. His notes are graphic and detailed. In the office, he posts his notes on the standard maps and sections and on special maps for correlation purposes. With the approval of the chief or assistant chief geologist, he recommends development work underground and watches its progress. This gives the geological department a precise knowledge of the character of each orebody. Sampling is done by one or two samplers at each mine working under a chief sampler stationed in the geological office. The chief sampler has access to all the office maps and is in frequent consultation with the geologists; his instructions to the samplers are issued with the approval of the chief or assistant chief geologist. Not only is it important that the geologic information be used to direct the sampling but the reports of the samplers and the records kept by their chief are useful to the geologist, who needs them in his work of I estimating ore reserves and deciding on recommendations for development work. The sampler, moreover, is at the mine every day and makes a daily report, which keeps the geologist in close touch with 'the progress of development work. The sampler is attached to the mine office and thus comes under the jurisdiction of the operating department. In fact, any special orders prepared by the chief sampler are submitted to the general superintendent, after approval by the geological department. The mine foreman may.

Jan 2, 1922

By Jean L. Leroy

The Lead Smelting works of Metallurgie Hoboken S.A. are located on the banks of the river Scheldt a few miles South of Antwerp. Lead refining began at Hoboken in 1687, when it was restricted mainly to desilverizing lead bullion from Central America. Since then, various changes have been made to develop the works into a comprehensive and integrated custom smelter and refinery. Multiple hearth roasting furnaces, down-draft sinter machines and blast furnaces of standard design are used for the treatment of "complex" lead ores and secondary materials. A lead refinery based on the Harris process, with Parkes desilverizing followed by vacuum dezincing and Kroll Betterton debismuthizing was commissioned in 1967. Facilities for the recovery of precious metals, bismuth, antimony, arsenic and sulfuric acid are available. Special problems arise from the presence of large quantities of copper in the materials treated.

Jan 1, 1970

By Frank A. Wilder

The most important process in a gypsum mill is calcining the crude mineral. There seems, however, to be little progress or change in calcining methods. This would not be surprising if the industry was not, in other ways, developing. The demand for gypsum in its various forms, however, is growing rapidly. The output has more than doubled in six years, while the value of gypsum products, through the introduction of higher priced. specialties like wall board, has nearly trebled in the same period. In other industries, under somewhat similar conditions, calcining in rotating cylinders, either by direct or indirect heat, has replaced the method that still prevails in gypsum mills. Efforts were made to use rotary calciners in manufacturing plaster of Paris in the early days of the industry in America; 25 years ago rotary calciners were in use in Germany. At that time there was great diversity of opinion in regard to their merit. In 1923, the output of calcined gypsum in the United States was 3,101,378 tons. About nine-tenths of this material was calcined in kettles, the remainder in rotary calciners. The ratio was about the same 10 years ago. During these 10 years, rotary calcining made relatively no gains, and there were no important changes in the construction of kettles. In their manipulation, the only change of consequence was in connection with the length of time that the gypsum is left in the kettle. For wall-plaster purposes, all producers who had not previously done so changed from second-settled to first-settled calcined gypsum, thereby reducing production costs and improving the plasticity and sand-carrying capacity of their plaster. Nevertheless, in the few mills in which they were installed, rotary calciners continue to operate, with possibly one or two exceptions, and to be highly successful. In these 10 years, the Cummer type of rotary calciner has disappeared. All rotaries now used are of the cement-mill type with a diameter of 6 or 7 ft. and length of 80 to 120 feet.

Jan 1, 1925

By William Fink

ALTHOUGH age-hardening in an aluminum-base alloy containing magnesium was observed by Alfred Wilm1 as early as 1911, it was not until 1919 that a theory of the mechanism of age-hardening was proposed. Merica, Waltenberg and Scott,2 studying the age-hardening character-istics of Duralumin at the National Bureau of Standards, came to the conclusion that age-hardening of this alloy is caused by the precipitation of CuAl2, which is less soluble at the aging temperature than at the solu¬tion heat-treating temperature. It was postulated that the initially precipitated particles were of fine colloidal dimensions but that they gradually grew in size. Maximum hardness was assumed to be attained when the particles reached a critical size. This theory was at first received skeptically, since it was a widely accepted view at that time that the solid solution state should represent the hardest state of an alloy. Shortly thereafter, Jeffries and Archer proposed their well-known "slip interference theory."3 They suggested that age-hardening was accomplished by the precipitated particles acting as keys interfering with slip along crystallographic glide planes. They showed that this mechanical theory led directly to the assumption that maximum harden-ing would be produced by particles of a critical size, which they suggested would have a diameter approximately 10 times that of the aluminum atom. This contribution amplified and explained so rationally the age-hardening theory of Merica, Waltenberg and Scott that wide accept-ance resulted.

Jan 1, 1939

By James P. Kimball

By the term weathering of coal is meant the process of deterioration to which under various circi~mstances it may be exposed at ordinary temperatures, both from outward agencies on the one hand, and on the other hand from its own constitutional qualities. This process involves along with some minor qualitative changes certain quantitative changes resulting in a gradual and limited reduction in the quantity of the organic elements, and relatively a corresponding increase of its inorganic or mineral constituents as represented by its ashes, and often in an increase of the absolute weight of the coal. In common with many mineral substances, coal absorbs oxygen

Jan 1, 1880

Adams, Bernard, Student, South Dakota School of Mines. Rapid City, S. D. '30 Ahlskog, Harold A., Student, Washington State College Pullman, Wash. '30 Aldridge, John, Student, New Mexico School of Mines Socorro, N M. '30 Almstrom, Adne A., Student, Met. Engrg., Washington State College Pullman, Wash. '29 Ancell, Virgil F., Student, Missouri School of Mines Rolla, Mo. '30 Ankudinoff, N., Mill Draftsman, Arthur G McKee & (:o., 2422 Euclid Ave., Cleveland, Ohio. '30 Apablasa, Salvador C., Student, Univ. of California Los Angeles, Cal. '31 Armstrong, Robert H., Student, Lafayette College Easton, Pa. '31 Armstrong, Thomas E., Student, Univ. of California Los Angeles, Cal '31 Aud, Robert A., Student, Lafayette College Easton, Pa. '30 Backus, Robert Small, Student, Mass.- Inst. of Tech . Cambridge, Mass. '30 Bailey, William C., Student, Univ. of California Los Angeles, Cal '30 Banning, Lloyd H., Student, South Dakota State School of Mines Rapid City, S D. '81 Barclay, M. G., Student, Colorado School of Mines Golden, Colo. '30 Barger, Thomas, Student, Univ. of North Dakota Grand Forks, N. D. '29 Barker, C. L., Student, Colorado School of Mines Golden, Colo. '30 Barker, Edgar Morgan. Student, Univ. of Utah Salt Lake City, Utah. '31 Barnwell, Earl E., Student, Oregon State College. Corvallis, Ore. '30 Bartholomees, Geo. C Box 304, Bonne Terre, Mo. '29 Bartholomees, Louis P., Student, Colorado School of Mines Golden, Colo. '30 Bary, Robert L., Student, Univ. of Kansas Lawrence, Kans. '30 Basham, Lester G., Student, South Dakota School of Mines Rapid City, S D. '31 Bates, Walter H., Student, School of Mines, Univ. of Utah .. Salt Lake City, Utah. '30 Beardshear, George T., Student, South Dakota State School of Mines.Rapid City, S D. '31

Jan 1, 1923

By T. N. Andersen, K. J. Richards, C. N. Wright

The kinetics of the important reactions occurring in an electrowinning cell have been determined. This information has been used to quantify relationships between the operating variables of current density, solution composition, agitation, and temperature and the resulting current efficiency and deposit quality. Analysis of these results has shown (1) the importance of dissolved iron in determining maximum possible current efficiency and corrosion rate at the cathode suspension loop, (2) the role of agitation, current density, inert salts and temperature in*determining deposit quality and (3) the effects of non-uniformity in the hydrodynamic conditions from the bottom to top of the cell. The significance of the results of this study to the operation of a commercial plant directly treating acid leach solutions is discussed.

Jan 1, 1973

By Edward Walsh

In the early history of the production of metallic iron from the native oxides or ores, success attended the labors of the workman according to the care he devoted to his work, and according to the degree of skill he possessed in furnishing the required amounts of fuel and ores to be acted upon by the blast propelled by the bellows, trompe, or wooden tub, and delivered into the hearths of the Persian, bloomery, or Catalan forges. The same skill may also have been of avail in the use of the lower forms of the ".Stück," "Blue,"or" Wolf"

Jan 1, 1887

By Alvin H. Lense

In the spring of 1967, after a careful study of existing geology along the Pacific Coast including Alaska, the USBM, in conjunction with the USGS, decided that the offshore area around Nome, Alaska, presented an unparalleled land-to-sea comparison site for the evaluation of marine core drilling techniques and sampling equipment. Considering the geological evidence available and the production history of the Nome Beaches (5-6 million oz. of gold recovered), it appeared likely that gold in commercial quantities could occur in the offshore area. A 180 sq mi area of Norton Sound, extending roughly 14 miles to the east and west of Nome and averaging 6 miles to the south, was tested by approximately 530 line-miles of sub-bottom profiling. A total of 4043 ft (56 holes) were drilled in unconsolidated sediments, yielding mixtures of gravel, sand, silt and clay. Of the total holes drilled, 16 went to bedrock and six were terminated short of their intended depths due to boulders which halted penetration, or rough seas which caused the ship to move as the anchors slipped over hard sea-floor surface. The rest of the holes were terminated when the penetrative capabilities of the drills were reached, or when the required amount of geological data were attained.

Jan 8, 1968

By J. H. Westbrook

UNTIL very recently the development of high temperature alloys has been strictly empirical. It is, in fact, a great tribute to the intuition, perseverance, and industry of the practicing metallurgists of this country and abroad that the amazing increases in gas turbine service temperature over the past 15 years have been achieved with so little fundamental knowledge. The result of this development has been the realization of successful but highly complex alloys possessing five, six, or more alloying elements and correspondingly complex microstructures. Within the last few years, considerable effort has been devoted to the identification of the secondary phases in these alloys and to the correlation of the presence or absence of such phases with alloy properties. Little attention, however, has been given the problem of identification of the mechanism (s) by which such phases enhance the properties of the alloy and especially to the assessment of the particular properties of the secondary phase (either in- trinsic or relative to the matrix phase) which are basically responsible for the improvement. Conceivable mechanisms which might apply include dispersion hardening and precipitation hardening. In both cases geometrical factors—particle size, dispersion, volume fraction, etc.—and agglomeration re-

Jan 1, 1958

By Herbert Clark Hoover, Lou Henry Hoover

We give the following brief notes on early works containing some reference to mineralogy, mining, or metallurgy, to indicate the literature available to Agricola and for historical notes bearing upon the subject. References to these works in the footnotes may be most easily consulted through the personal index. GREEK AUTHORS.-Only a very limited Greek literature upon subjects allied to mining or natural science survives. The whole of the material of technical interest could be , reproduced on less than twenty of these pages. Those of most importance are : Aristotle (384-322 B.c.), Theophrastus (371-288 B.c.), Diodorus Siculus (1st Century B.c.), Strabo (64 B.c.-25 A.D.), and Dioscorides (1st Century A.D.). Aristotle, apart from occasional mineralogical or metallurgical references in De Mirabilibus, is mostly of interest as the author of the Peripatetic theory of the elements and the relation of these to the origin of stones and metals. Agricola was, to a considerable measure, a follower of this school, and their views colour much of his writings. We, however, discuss elsewhere1 at what point he departed from them. Especially in De Ortu ct Causis does he quote largely from Aristotle's Meteorologica. Physica, and De Coelo on these subjects. There is a spurious work on stones attributed to Aristotle of some interest to mineralogists. It was probably the work of some Arab early in the Middle Ages.[ ]

Jan 1, 1950

By R. V. Wheeler

A matter of much concern at present to the coal-mining industry of Great Britain is the effect of the working of the Coal Mines Act, 1930. This Act, which received the Royal Assent on Aug. 1, 1930, contains five parts: (1) production, supply and sale of coal; (11) the reorganization of the coal-mining industry; (111) hours of work; (IV) the Coal Mines National Industrial Board; (V) general. The first three parts are of major interest and discussion can be confined to them. Part I.—Production, Supply and Sale of Coal Under Part I of the Coal Mines Act, 1930, provision is made for central and district schemes to regulate the production, supply and sale of coal by the fixation of standard tonnage, quota and minimum prices. By Nov. 1, 1930, all the district schemes came into force with the exception of that for Scotland, where the majority of the coal-owners did not see their way to accept the amendments to their draft scheme demanded by the Mines Department. A compulsory scheme for Scotland was thereupon prepared by the Mines Department and put into force on Nov. 24, 1930. It is administered by the coal-owners of the district. The essence of the schemes is the allocation of tonnage for each district by a Central Council, and the allocation of quota for each pit in a district by an Executive Board for that district. Up to Dec. 31, 1930, the various bodies of coal-owners engaged in administering the schemes were employed in work preliminary to their full operation. Standard tonnages had to be determined and coals had to be classified. In consequence, it was not found possible to put the regulation of output into force until Jan. 1, 1931. The determination of minimum prices proved to be an even longer process, and only in a few districts were minimum price schedules operative during the first quarter of this year. The working of the schemes during the March quarter, 1931, has been reviewed in an official publication by the Mines Department,' which can be summarized as follows:

Jan 1, 1932

By L. O. Howard

TWO or three years ago there were submitted to me some reports of tests that had been made on a semi-oxidized ore of silver looking to its treat-ment by combined flotation and cyanidation, together with a sample of the ore, with a request that I check the tests and confirm them, if possible. These tests had been made by a machinery-supply house and with them was a flow-sheet for a proposed mill, with full details of equipment to be used in the mill. The limited data on which this was based at once attracted my attention and have caused me from time to time to put various groups of students at work to develop simpler methods of obtaining data, which it appeared should be at hand and could be obtained by simple tests before attempting to treat these ores commercially. A brief discussion of the working out of such methods may be of interest and may contribute somewhat to the de-velopment of better testing methods for the small operator who has not at his command a staff of metallurgists. Of several tests on samples of varying assay and mineralogical composition, by cyanidation alone, by flotation alone, and, by combinations of the two, the following report was perhaps the most complete and may well serve as a typical example: METALLURGICAL TEST REPORT Silver Mines Co. Semi-oxidized Ore Procedure: Ore ground to 65 mesh, given flotation treat-ment using pine oil and potassium xanthate. Flotation tailing was thickened and given cyaniding agitation in solution strength of 5 lb. cyanide per ton and 2 lb. lime per ton.

Jan 12, 1927

By A. L. Mular

Optimization strategies of possible interest to mineral processing are reviewed and typical strategies initiated in processing plants to date are discussed. Both On-Line and Off- Line optimization procedures have been employed by industry, assisted either by operators or by digital computers. In every case, dollar benefits have accrued.

Jan 1, 1976

By R. L. Smith, J. L. Rutherford

ALTHOUGH considerable effort has been devoted toward the determination of the mechanical properties of pure metals, it is extremely difficult to compare the results of such work. This is because of differences in method and type of test, grain size, heat treatment, and purity of material. There is very little information on the properties of most of the high melting point reactive metals with purities greater than 99.9 pct. Previous evidence concerning the tensile properties of unalloyed metals show that: body-centered-cubic metals are brittle at low temperatures; face-centered-cubic metals remain ductile; some hexagonal metals remain ductile, others become brittle. It may be that traces of impurities decrease the low temperature ductility of the body-centered-cubic lattice. This would suppose that a body-centered-cubic lattice free from impurities would exhibit nearly the same ductility as a face-centered-cubic structure. The present investigation has been an evaluation of the tensile properties of zone refined iron in order to determine whether higher purity material than that previously evaluated behaves differently. Experimental Procedure In this investigation, high purity iron was zone purified using the floating zone method.' The starting stock was obtained from two sources. The first,

Jan 1, 1958