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By John L. Walte

Consolidation Coal Co.'s Renton mine, a 680 000-t/y (750,000-stpy) underground operation located in western Pennsylvania, has reduced the time required for overcast construction in its advancing operations by adopting a prebolting technique followed by multiple blasting. In the past, the mine's overcasts had been excavated by the continuous mining machines used to advance the section. More recently, the overcasts were blasted down and then rebolted with a stoper drill. The new system, using a two-part combination bolt, has proven very successful in speeding up overall construction time and providing more positive horizontal control in blasting. The prebolting approach allows the roof to be blasted down and loaded out without the need for rebolting the shot-out area.

Jan 6, 1978

By Martin J. Gungl, J. Lyman MacInnis

None of the industry submissions could persuade the Canadian Tax Reform draftsmen that the rate of return has had as much bearing on investors' decisions to invest in Canada as the success records of Canadian ore findings. The goverment opted for the position that mining capital goes where the ore can be found. Many tax incentives which were available until the end of 1971 have been greatly reduced. However, it is still recognized that new ventures in exploration and development of natural resources deserve a break even if there is reduced recognition of the established and highly successful members of the industry unless they continue to search and develop. The latter will also get some breaks for processing beyond the prime metal stage.

Jan 7, 1972

By R. A. Vandermeer, J. C. Ogle

The preferred crystallographic orientations (texture) developed in randomly oriented, poly crystalline niobium during rolling were studied by means of X-ray diflraction techniques. The evolution of texture at both the surface and center regions of the rolled strip was carefully examined as a function of increasing defamation throughout the range 43 to 99.5 pct reduction in thickness. Certain aspects of the center texture development in niobium are in agreement with the predictions of a theory by Dillamore and Roberts, but others cannot be explained by the theory in its present form. Above 87 pct reduction by rolling, a distinctly different texture appeared in the surface layers which was unlike the center texture. The present results are compared with previous results obtained from other bcc metals and alloys. RANDOMLY oriented, poly crystalline metal aggregates when plastically deformed to a sufficiently large extent develop preferred orientations or textures. In a recent review article, Dillamore and Roberts1 pointed out that the nature of the developed texture may be influenced by a large number of variables. These include both material variables such as crystal structure and composition and treatment variables such as stress system, amount of deformation, deformation temperature, strain rate, prior thermal-mechanical history, and so forth. From a practical point of view, the control of preferred orientation may often be important for the successful fabrication of metals into usable components. During the past few decades many experiments have been devoted to the study of deformation textures. This work, however, has been confined in large part to metals and alloys that have an fcc crystal lattice. By comparison, bcc metals and alloys have received much less attention, and consequently our understanding of preferred orientations in these materials is only shallow. This state of affairs worsens when it is realized that almost all of our present howledge about this class of materials derives from studies on irons and steels.' The bcc refractory metals, which are relative newcomers to the industrial world, have, on the other hand, been given at best only passing glances in the area of texture development. Our understanding of the evolution of preferred orientations in bcc metals can only remain fairly limited until systematic studies of metals and alloys other than the irons and steels have been carried out and the influence of the many variables has been determined. To that end a program was initiated to investigate in detail texture development in niobium. The present paper reports some of the results of this study. Textures were determined at both the center and surface of strips rolled variously to as much as 99.5 pct reduction in thickness at subzero temperatures. Emphasis in this paper is on texture description and on texture evolution during rolling to progressively heavier deformation. EXPERIMENTAL PROCEDURE The niobium was purchased from the Wah Chang Corp. as a 3-in.-diam electron-beam-melted billet. Chemical analysis indicated the impurities to be less than 300 ppm Ta, 40 ppm C, 10 ppm H, 170 ppm 0, and 110 ppm N. All other impurities were below the limits of detection by spectrochemical analysis. This large-grained billet was fabricated into specimen stock so that a fine-grained randomly oriented grain structure resulted. This was accomplished in three deformation steps alternated with recrystalli-zation anneals of 1 hr at 1200°C in a vacuum of low 10"6 Torr range after each deformation step. The first step was to alternately compress the billet 10 to 20 pct in each of three orthogonal directions. The second step was to compress in only two directions 90 deg apart to produce a 2-in.-sq bar. The final step was to roll this bar 50 pct to give a 1-in. by 2-in. cross section. After the final anneal, metallo-graphic examination showed the material to have an average grain size equivalent to ASTM No. 5 at 100 times (i.e., 0.065 in. diam). Specimens cut from the center and edges of this bar gave no indication of detectable preferred orientation when examined by X-ray diffraction. Samples 1.5 in. long, either 0.625 or 0.750 in. wide, and approximately 0.400 in. thick were machined from this fabricated ingot. The surfaces corresponding to the rolling planes were ground so as to be parallel. The samples were chemically polished in a solution of 60 pct nitric acid and 40 pct hydrofluoric acid (48 pct solution) prior to rolling to remove any cold work introduced in the machining operations. Rolling was accomplished with a 2-high hand-operated laboratory rolling mill that had 2.72-in.-diam rolls. Prior to operation, the rolls were polished with 600 grit paper, cleaned with acetone, and then soaked in a container of liquid nitrogen for several hours. The samples were also soaked in liquid nitrogen prior to rolling and were recooled between each pass. While some slight heating of the samples occurred during rolling, this procedure maintained the sample temperature well below 0°C at all times. The samples were rolled unidirectionally, and the rolling plane surfaces were not inverted during any phase of the operation. The draft per pass averaged between 0.010 to 0.012 in. After 96 or 97 pct reduction the draft was reduced to 0.001 to 0.002 in. per pass. Samples were rolled to various reductions in thickness between 43 and 99.5 pct.

Jan 1, 1969

By J. Absil, H. Dreissen

Upgrading low-concentration ores is of increasing importance today. The heavy medium cyclone process, due to strong centrifugal forces, effectively separates particles varying only slightly in specific gravity but widely in size. The paper discusses separation efficiency, assessment of that efficiency, and the influence of such factors as medium solids. The operating results of nine heavy medium cyclone plants, each handling a different mineral, are reported.

Jan 1, 1982

By Suzanne T. Mathis, J. C. Ferm, J. T. Berger, W. Horger

A system of core logging and computerized entry and retrieval is described which permits accurate and rapid logging of core, cuttings and geophysical records derived from exploration and development bore holes. The system is so constructed that older drilling records can also be utilized. Output consists of conventional computer print out and graphic logs with a variety of scales, symbols and formats. Such logs can be used in constructing rock profiles which are necessary in property assessment and mine development.

Jan 1, 1983

Discussion of the paper of O. P. Hood, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October, 1914, pp. 2607 to 2611. R. V. Norris, Wilkes-Barre, Pa.-I have had a little experience with gasoline locomotives and I want to indorse very strongly Mr. Hood's point with regard to the danger of carbon monoxide poisoning. I think .the terrible danger is not fully realized. I was foolish enough some time ago, in investigating a gasoline locomotive, to attempt to walk out of the mine entry behind it, and for several days I felt very seriously the carbon monoxide effects. The use of gasoline locomotives ought to be confined to mine entries where there is a very large amount of air. One of the grave dangers is their great convenience and the temptation to run them into chambers for just a few moments to get a car or two. GEORGE S. RICE, Pittsburgh, Pa.-Apparently one of the great dangers is in the style of the gasoline engine. When my attention was. first directed to the type of gasoline locomotives which I saw in the foreign mines-France, Belgium, and Germany, I was most favorably impressed with them, and they have given no trouble on account of fumes, so far as I could learn. Large numbers of them were being used, but all were of small capacity, and of a kind in which the speed control is by a governor of the hit-or-miss type, the engine running continuously. Their power capacity was very low, if I remember correctly it was not over 4 or 5 h.p., but they were used under favorable conditions where the grades in the mines were slight, since the entries or tunnels bad a slight grade in favor of-the load, making about the same pull for the empties against the grade as for the load with the grade. I understand the hit-or-miss valve arrangement enables a setting that will give more perfect combustion than can be insured with the valve controlled by the operating man, as in the automobile type of valve and engine used in this country. Apparently the European type of locomotive does not have the capacity to permit use under the conditions existing in this country, where most of our entries or tunnels have variable grades and long heavy trips of mine cars are used.

Jan 4, 1915

By AIME AIME

WHEN a local man has attained high position in business and civic affairs at home, his fellow citizens feel elated if his attainments are given recognition in the form of election to office in an organization of national scope. Eugene Ainsworth White, a new Director of the Institute, is one of the must prominent citizens of Tacoma, where for the past thirteen years he has managed the Tacoma Smelter of the American Smelting and Refining Co. A list of the civic duties he has carried with distinction would be a long one; for recent years it would show that he has been chairman of the Community Chest, vice-president of the Chamber of Commerce. and a member of the Pierce County Taxation Bureau.

Jan 1, 1945

By AIME AIME

For the convenience of persons who desire to file, or otherwise use separately, the technical papers in Section II of the Bulletin, each of these papers has been paged and wired by itself; the whole collection being held together by a single, heavy wire, upon the removal of which it will fall apart into individual pamphlets, substantially like those formerly issued. A small stock of separate pamphlets, duplicating the technical papers given in Section II of this Bulletin, is reserved for those who desire extra copies of any single paper. All communications concerning the contents of this Bulletin should be addressed to Dr. Joseph Struthers, Assistant Secretary and Editor, 29 W. 39th St., New York City (Telephone number 4600 Bryant).

Jan 1, 1907

By James J. Bean

Although determining and controlling specific gravity of operating medium in a heavy-media plant manually presents no problem, there are advantages to automatic recording and control. The two installations discussed employ the usual method of measurement. Pneumatic control with band control and reset features is used to regulate dilution water and hence specific gravity. Difficulties have been mechanical in nature and associated with obtaining a proper sample and maintaining tight air connections in bubble-tube piping.

Jan 3, 1950

By William Glenn

That basic slag will rapidly destroy ordinary (i.e., siliceous) fire-bricks is known to every smelter; and the smelter of copper-ores in particular knows that any kind of slag occurring in his practice is destructive. From this fact arises the chief distress of those who attempt to smelt copper-ores in any manner of furnace constructed of bricks or stone, or other similar material. We have passed the fire-brick stage of our experience; and now, having entered upon the period of the water-jacketed cupola, we will employ no furnace other than that having steel walls, kept cool by water. But,, unfortunately, the bottom of a water-jacketed cupola, kept cool by another water-jacket, fails of its purpose, being thereby made so cold as to chill both slag and regulus to a degree not bearable. The situation is more or less ameliorated when the upper surface of the water-jacketed bottom is covered with fire-bricks, since, so long as they last, they prevent the molten material from contact with the cold bottom. My own observation leads me to suppose that most smelters construct cupola-bottoms of iron slabs, which are covered, to a greater or less depth, with fire-bricks. There are cupola-bottoms which

Jan 1, 1902

By A. Weiss

Operations Research developments within the mining industry have evolved over the last few years through stages typical of any new technique. By 1965, most companies had passed from mere recognition of the usefulness of operations research techniques to cautious acceptance of and, in some in- stances, to confident utilization of this relatively new tool. This is reflected in the growing interest and increasing participation of mining companies in sponsoring individual papers on the subject published in mining journals or presented in full sessions at annual meetings. Chief among the sources which served, in 1965, as a barometer for measuring operations research progress within mining is the Annual Symposium on the Applications of Statistics, Operations Research, and Computers in the Mining Industry, which is now sponsored by the University of Arizona, Stanford University, Colorado School of Mines, The Pennsylvania State University, and the Society of Mining Engineers of the AIME. Two significant trends were evident in the applications of operations research techniques to problems typical of the mining industry. On the one hand, unique and imaginative O.R. applications were being developed by several companies, government agencies, and at the university level. These techniques were usually developed to solve specific existing problems. On the other hand, there was unmistakable evidence of attempts to look for problems which could be solved with those "operations research" approaches which would involve the use of the digital computer. In the latter instance, solutions may become applications or demonstrations of how the computer can be used in the reduction and interpretation of data, without the benefit of a decision model. This is a common tendency as most companies have computers, at least in their accounting sections, and many operations research solutions require the use of a digital computer. From the applications observed in 1965 and in prior years, the successful techniques have evolved.

Jan 2, 1966

By Arthur S. Dwight

The profeseional career of Thomas Septimus Austin, who died at El Paso, Tex., Aug. 23, 1906, was contemporaneous with the growth of the silver-lead smelting-industry of the Far West, to which his talents and zeal contributed in no small degree. Born at Stratford, Conn., Dec. 7, 1853, he was the seventh son in a family of thirteen. His parents were well-to-do; and he received a thorough preliminary training at the Hopkins Grammar School, New Haven, Colin., passing thence to the Columbia School of Mines, in New York, where he was graduated in 1876. His first professional work was that of analytical chemist with a Cuban sugar company. In this position he spent a year, and, whatever else of benefit he may have acquired during that year in Cuba, he gained a facility of speech in the Spanish language which was of inestimable value in his subsequent work in Mexico and the southwestern United States. In 1877, he went to the Rocky Mountains, and, under the firm name of Murphy & Austin, opened an assay-ofice in Lead-ville, Colo., which was just then coming into public notice as a rich silver-lead camp. The next year, however, he entered the service of the Germania Smelting & Refining Co. at Salt Lake City, Utah, where he remained until 1882, first as assayer and chemist, and later as Assistant Superintendent. The Germa-nia bears the honorable distinction of being one of the first of the large " custom" lead-smelters erected in the West. Its founders may be called the pioneers of the modern lead-smeltr ing practice, and the Germania served, to a large extent, as a model for the many plants that sprang into existence during the next few years in Utah, southern Idaho, Colorado and other lead-producing districts. The formulation, for the first

Jan 1, 1908

By E. E. Duncan, G. Derce

REVIEW of the literature on hydrogen in steels indicates that inadequate consideration has been given to the influence of temperature gradients on segregation of this element. Even when segregation has been taken into account, the interpretation of the data has been seriously handicapped by incomplete understanding of the mechanism by which it occurred. Recognition of a mechanism which will be described as "thermal segregation" appears to rationalize many of the observed effects so well that it will be reported here with some preliminary experimental evidence. The complete quantitative evaluation of the factors controlling the mechanism will require extensive experimentation. The operation of the mechanism can be described in relation to fig. 1, which shows the temperature dependence of the solubility of hydrogen in iron at

Jan 1, 1951

This story of the salting of a supposed diamond mine is a part of our Western history and deserves to be recorded in this book. It was more than a local affair, because it was concerned with persons in London and New York, as well as San Francisco. Part of the story has been told by Asbury Harpending in a little book published 12 years ago. Harpending (who died at New York in 1923) was in London in March, 1872, when he received a cable dispatch from William C. Ralston, the president of the Bank of California, stating that "a vast diamond field" had been discovered "in a remote section of the United States". Before starting for San Francisco, Harpending had an interview with Baron Rothschild, who showed a lively interest in the story, which was as follows: two weather-beaten prospectors went to the Bank of California and deposited some uncut diamonds and rubies for safe keeping; these precious stones were estimated to be worth $125,000. The men said that they had found the gems in "a desert portion of the West". They departed quietly, but the story was told in business circles; whereupon George D. Roberts, a mining engineer of wide experience and an associate of Ralston, sought an interview with the prospectors. One of them proved to be a man that had been in the employ of Roberts. Both prospectors, named Slack and Arnold, appeared "coy and cautious"; they were "simpleminded fellows", and were "afraid to trust anyone with the momentous secret ". They refused to divulge the place of discovery and declined "to part with their rights", but later "they became more amenable to reason" and expressed willingness to sell a half interest to

Jan 1, 1932

By Edwin R. Phelps, Charles W. Porterfield

BACKGROUND OF SURFACE MINING Surface mining refers to the process of removing the material (over- burden) overlying a coal seam and exposing the coal so that it can be loaded out and conveyed by trucks or other methods to the preparation plant or other facility. Surface mining has not always been important in the coal industry. In the early 1900s, almost all of the coal mined in the United States was mined by underground methods. In 1900, about 192 Mt (212 million st) of bituminous coal were mined and less than 1% was mined by surface methods. The development and use of larger equipment has allowed surface mining to gain prominence throughout the years. Table 1 shows the total production of coal by mining method in the United States for ten-year periods since 1920 and indicates the growth of surface-mined coal production. Surface mining will undoubtedly continue to account for a large percentage of the coal production in the US for many years because: 1) The capacity of surface mining excavators has continued to in- crease. Today, mining companies are using shovels (see Fig. 1) which are able to move up to 137.6 m3 (180 cu yd) in each bite and draglines (see Fig. 2) which move up to 168.2 m3 (220 cu yd) in each bucketful. 2) Increasing tonnage from the thick western coal seams is being produced by surface mining methods. 3) Surface mining has normally had lower costs and a better safety record than underground mining. 4) Surface mining normally recovers a much higher percentage of the coal reserve than can be recovered by underground mining. 5) Some coal measures can best be extracted by surface mining

Jan 1, 1981

By D. E. Wolfson, H. J. Gluskoter, M. R. Geer, John A. Harrison, H. F. Yancey, I. S. Latimer

When this chapter was prepared for the kst edition in 1942, continuous mining machines virtually were unknown, and hand loading in underground mines, which gave an opportunity to discard impurities, accounted for 55 percent of the production of bituminous coal and lignite as compared with the 1965 figure of 11 percent. Only 24 percent of the total production was cleaned mechanically, compared with the present (1965) figure of 65 percent. The amount of refuse discarded during preparation for the same period increased from 13 to 21 percent. Changes in the equipment used in the cleaning process were as follows: [ ] Unclassified nearly 8 percent. Data on the amount cleaned by flotation was not collected until 1960 when 1.8 million net tons was so treated. In 1965 this figure increased to 6.9 million tons. Although the great increase in mechanization and full seam mining has resulted in substantial increases in the impurity content of the raw coal as well as in a finer size consist, some phases of face preparation are still important, particularly the variability of the distribution and thickness of the interbedded impurities and the changes in the character of the roof and floor from place to place in the mine. Knowledge of these factors in relation to all phases of the mining operation, particularly selective mining, are still of importance to the treatment of raw coal in the preparation plant. The major characteristics of coal and impurities from the standpoint of mechanical cleaning are particle size composition, generally called size consist, density differences, the relative friability of the coal and of its associated impurities, hardness, and strength. Some of the other factors related to preparation are petrographic composition and rank. COAL PROPERTIES Rank Perhaps 95 percent or more of the coal cleaned mechanically is of bituminous rank. Only a very small tonnage is subbituminous and prac-

Jan 1, 1968

By MILNQR ROBERTS

THE Nicola Valley coal-field is small, but it seems likely to become important because of its commanding position in a rich region that is developing rapidly. Bituminous coking coal in workable quantity has not been found at any other point between the Crow's Nest Pass region, about 400 miles to the east, and Vancouver island, 250 miles westward. The Canadian Pacific railway reached the Nicola valley two years ago; two other lines, the Canadian Northern and the Great Northern, are building towards the valley. The vast region between the Rocky mountains and the Pacific coast, extending northward for several hundred miles from the international boundary, which has been the scene of extensive mining- and smelting-operations for many years, is filling up with settlers, who are attracted by the wealth of minerals and timber, the rich soil of the valleys, and the fine climate. The Nicola river, flowing westward through the valley of that name in the Yale district, discharges into the Thompson river, which is the eastern branch of the Fraser. The transcontinental line of the Canadian Pacific railway crosses the mouth of the Nicola river at Spence's bridge, 178 miles from Vancouver. From Spence's bridge the Nicola branch line ascends the valley for 40 miles to Merritt, the coal-center, and continues 7 miles farther to the town of Nicola. Thus the haul from the mines at an elevation of 2,000 ft, to saltwater is 218 miles down river grades. The Nicola branch will be continued about 150 miles farther eastward to Penticton, where it will connect with an extension of the line through the rich Kootenay and Boundary districts. The Canadian government has granted a subsidy of $6,000 per mile, to which the pro-

Jan 1, 1910

By Karl Sundberg

ElectRical investigations carried out in regions containing sedimentary rocks showed that sediments generally are good electrical conductors, a fact which at the present time is used for structural investigations by electrical methods. It is of fundamental importance, not only for these investigations but also for electrical prospecting in general, to know the electrical properties of various soils and rocks. It will be useful, therefore, to discuss this question with the hope that the general points of view discussed in this paper will perhaps be completed by further observations and determinations of material from various localities. This paper is based principally on the study of literature, and the purpose is primarily a discussion of the main factors that determine the electrical conductivity of soils and rocks. It will follow, however, that the factors discussed here also frequently decide how far a certain orebody can be regarded as a good electrical conductor compared with the surrounding rocks. All rocks are more or less porous, and the pores are filled with liquids and gases. Their electrical conductivity, therefore, depends on the following factors: 1. The electrical conductivity of minerals composing the rock. 2. Electrical conductivity of the liquid filling the pores. 3. Proportion of the volume of liquid filling pores of the rocks to the solid rock material. 4. Shape of the pores. 5. Arrangement of the particles of gas and liquids. 6. Temperature. Dry minerals, with the exception of certain ore minerals, are complete nonconductors from the point of view of applied geophysics; in the present investigation we deal with rocks which have no conducting minerals, and factor 1, therefore, is not important. The same is true of soils. The liquids contained in soils and rocks in most cases are waters, sometimes oil. As oil is a nonconductor of electricity, the impregnating waters will determine the electrical conductivity of soils and rocks.

Jan 1, 1932

By M. C. Leverett

The behavior of mixtures of immiscible liquids in porous solids is of rapidly increasing interest to those engaged in the production of petroleum. The operation of artificial water-floods and the control of natural ones immediately raise questions concerning the fundamental nature of such processes. Moreover, it is now recognized that often water occurs dispersed throughout the rock from which the oil issues into the well,' and thus tends to move toward the well simultaneously with the oil. The work reported here is a laboratory investigation of the simultaneous, steady-state flow of oil and water through the same column of uncon-solidated sand. It is thus directly related to the situation in which water occurs in oil-producing sands; it may have less direct implications for the displacement of oil from sands by water. However, it is to be clearly understood that the experiments to be described were performed primarily to obtain information of a more or less fundamental nature, and are not an attempt to reproduce, on laboratory scale, any part of an oil field. The dynamic behavior of a system in which oil and water are flowing simultaneously through sand is best described in terms of its "effective permeability" to either phase. For incompressible fluids flowing through a system of uniform cross section, the effective permeabilities to the two phases, in darcys, may be defined by the equations: Ko = PA6A [la] and Ku = Q [lb] In order to put the results obtained on a comparable basis for different sands, the effective permeabilities will be stated as fractions of the normal permeability of the sand; i.e., fractions of its permeability to a homogeneous fluid. Algebraically, these fractions are: KO' = Ko/K, and KWr = K,/X [2a] and [Zb]

Jan 1, 1939

By M. C. Leverett

The behavior of mixtures of immiscible liquids in porous solids is of rapidly increasing interest to those engaged in the production of petroleum. The operation of artificial water-floods and the control of natural ones immediately raise questions concerning the fundamental nature of such processes. Moreover, it is now recognized that often water occurs dispersed throughout the rock from which the oil issues into the well,' and thus tends to move toward the well simultaneously with the oil. The work reported here is a laboratory investigation of the simultaneous, steady-state flow of oil and water through the same column of uncon-solidated sand. It is thus directly related to the situation in which water occurs in oil-producing sands; it may have less direct implications for the displacement of oil from sands by water. However, it is to be clearly understood that the experiments to be described were performed primarily to obtain information of a more or less fundamental nature, and are not an attempt to reproduce, on laboratory scale, any part of an oil field. The dynamic behavior of a system in which oil and water are flowing simultaneously through sand is best described in terms of its "effective permeability" to either phase. For incompressible fluids flowing through a system of uniform cross section, the effective permeabilities to the two phases, in darcys, may be defined by the equations: Ko = PA6A [la] and Ku = Q [lb] In order to put the results obtained on a comparable basis for different sands, the effective permeabilities will be stated as fractions of the normal permeability of the sand; i.e., fractions of its permeability to a homogeneous fluid. Algebraically, these fractions are: KO' = Ko/K, and KWr = K,/X [2a] and [Zb]

Jan 1, 1939