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By E. P. Pfleider, W. D. Lacabanne

Rotary percussive drilling, vibro-drilling, vibro-rotation drilling, rotary pulsating drilling-all names that mean the same thing-are gradually appearing in mining literature. What is rotary percussive drilling? It is a combined system superimposing a rapid percussive impact on a continuous rotary action in an attempt to utilize the most desirable features of both methods. At present single and multiple carriage-mounted rotary percussion units are being used in the European coal mining regions. One well engineered unit is the Hausherr "Albo" rotary percussive drill, utilizing two alternately operating percussion pistons, and another is the multiple-unit, jumbo-mounted Salzgitter machine. Niisse & Grafer also manufacture rotary percussion drills.

Sep 1, 1955

By Richard N. Grigsby

INTRODUCTION The Chord property was acquired in 1975 from Roy Chord, an early prospector and miner of the area. He had staked numerous claims on the southern flank of the Black Hills in the early 19501s, and by the late 50’s, many small open pit and underground mines had been or were in operation. By the mid 1960's small tonnages of high-grade oxidized uranium ore had been mined from the property. Starting in 1975, Union Carbide conducted a series of exploration programs to determine the remaining economic potential. The previously mined areas were re-examined in order to define additional oxidized mineralization. Meanwhile, a wide-spaced drilling program was initiated to determine the potential for deeper unoxidized deposits. Through the exploration program of 1979, measured minable reserves in excess of two million pounds of contained uranium had been discovered. GEOLOGY The Edgemont District is located on the southern end of the Black Hills Uplift. A succession of pre-Cambrian to Cretaceous Formations is exposed within the core and across the flanks. The uranium host is the lower Cretaceous Inyan Kara Group which is divided into two formations, the Lakota and Fall River Formations (Figure 1). The basal Lakota Formation rests unconformably on the Jurassic Morrison Formation and consists of fluvial channel sandstones

Jan 1, 1983

By L. F. Reinartz

The furnace in which rimming steel is made has an important bearing on the quality of the steel produced. Furnace.—Particularly in the manufacture of low-carbon rimming steels, it is necessary to have an efficient, easily regulated furnace, because of the relatively high finishing temperature requirements. In recent years, the most important development in design of open-hearth furnaces has been the sealing and insulation of the greater part of the furnace to prevent air infiltration and loss of heat. Efficient, straight-line valves insure proper draft. Combustion controls guarantee correct gas-air ratios. Furnaces of all sizes ranging from 20 to 200 tons have been used successfully in the manufacture of rimming steels. Metal bath is varied from 20 to 40 in. in depth without appreciable variation in quality. Charging.—A normal open-hearth charge consists of pig iron (hot or cold), scrap of miscellaneous nature, and slag-making additions, such as limestone and burnt lime. Because of local conditions, some plants find it necessary to discard the use of pig iron and use some carbonaceolis substances with varying percentages of cast iron to replace the pig iron. It is questionable whether such practice will consistently produce the quality of rimming steel required for auto stampings and other severe drawing requirements. Pig Iron.—An open-hearth furnace under proper control should melt 150 tons of low-carbon rimming steel on about 35 to 38 per cent pig-iron charge basis. In some practices, best results are obtained when the total charge contains from 0.40 to' 0.50 per cent silicon. If reasonably low-

Jan 1, 1935

By John M. Dale

Sulfur has attractive features as a base material for coating systems. It melts at 246ºF and can be applied as a liquid above this temperature. Its melting point is just above the environmental stress level, 180°F, for most coatings and yet it is low enough to be easy to work with in comparison to many hot melt systems. The viscosity characteristics are such that sulfur lends itself to spray applications. The oxidation rate of sulfur in the atmosphere is very low and sulfur has outstanding chemical resistance characteristics, particularly in acid environments. One of the greatest potentials for these coatings appears to be in the protection of other materials. At one time, most acid tanks and pits were constructed with acid- proof brick and sulfur based mortars. This type of construction is much more expensive than sulfur based spray coatings. An attractive sulfur based coating composed of sulfur, talc, milled glass fibers and dicyclopentadiene,1 developed by the Institute for the Bureau of Mines has excellent acid assistance and can be used to protect concrete from acid attack.

Jan 10, 1973

By V. Runolinna, R. T. Hukki

Preliminary separation of precious metals by flotation can offer a simplification of the conventional method of treatment of anode slimes. Laboratory flotation experiments show that rich gold and silver concentrate can be obtained with excellent recoveries. THE purpose of this paper is to present the results of an investigation into the possibilities of separating precious metals from anode slimes by selective flotation. The work was carried out at the State Research Institute in Helsinki, Finland. The sample of anode slimes tested was submitted by the Outo-kumpu Co. in Finland. In 1947 the average assay of filtered and dried anode slimes in the Outokumpu refinery in Pori was as follows: Au, 0.50 pct; Ag, 9.38 pct; Cu, 11.02 pct; Ni, 45.21 pct; Pb, 2.62 pct; Fe, 0.60 pct; Sn, 1.00 pct; Sb, 0.04 pct; As, 0.70 pct; Se, 4.33 pct; S, 2.32 pct; SO,, 2.17 pct; SiO2, 2.25 pct. The daily assay naturally varies considerably from the figures presented above. The present conventional method of treatment of anode slimes consists of the steps shown in the flowsheet in fig. 1. As seen from this simplified flowsheet, the present method of treatment involves many steps by which the components of the anode slimes are removed one after another until the main products, gold and silver, may be separated. Due to the small scale of operations, the above procedure is carried out in small batches requiring considerable amount of manual labor. If, however, the anode slimes could be treated in

Jan 1, 1951

By 000-001-568

August 15th, 1871. THE Institute assembled in Packer Hall of the Lehigh University, the President, Mr. David Thomas, of Catasauqua in the chair. Professor Henry Coppée, President of the Lehigh University, made an address of welcome to the Institute, and placed at its disposal a convenient hall for purposes of meeting. Mr. Thomas tendered his resignation as President of the Institute, as advancing years prevented him from actively participating in its meetings. The Institute declined to accept the resignation, and, on the assurance that active duties would not be expected of him, Mr. Thomas was induced to withdraw it. Invitations were received from Mr. B. C. Webster, President of the Lehigh Zinc Company, to visit the mines and works of the company; from Mr. Charles Brodhead, to visit the Chapman Slate Quarries ; and from the Lehigh Coal and Navigation Company, to visit their works at Summit Hill and Mauch Chunk and the Nesquehoning Tunnel. The Council reported the names of persons already elected in the two classes of members and associates. The following resolutions were passed: Resolved, That a committee of three be appointed, who shall take into consideration the printing and publishing of papers originating with the Institute, and that a uniform system as regards size and execution be adopted. The committee appointed consisted of Messrs. R. W. Raymond, E. B. Coxe, and the Secretary. Resolved, That the Council design and prepare a seal for the Institute at the earliest practicable time. Resolved, That a committee of six, with power to add to its numbers, be appointed to examine into the question of the more economical production of iron in this country. The committee appointed consisted of Messrs. G. W. Maynard,

Jan 1, 1873

By W. B. Heroy

The rapid development of transportation routes on the African continent in recent years has greatly stimulated the demand for motor fuels and this in turn has led to more extensive exploration of such limited portions of the continent as seem to give promise of commercial oil production. In 1930, however, only two countries were classed as producers of petroleum and only one, Egypt, attained any importance. Egypt The petroleum production of Egypt is derived from the Gemsah and Hurghada fields on the west coast of the Red Sea and the Abu Durba, on its eastern shore in the Sinai peninsula. The Gemsah field, which began to produce commercially in 1912, has now practically ceased production, owing to the invasion of salt water. The Hurghada field has been producing since October, 1914. It now has about 60 producing wells. During 1929, a deeper sand with flowing produition was discovered in the eastern part of the field, producing oil of lighter gravity and free from water. The Abu Durba field was discovered by the exploration work of the Egyptian Government in 1918, oil having been found at a depth of 172 ft. This field has now 15 producing wells but a very small production. The production of these Egyptian fields over the last five years, is as follows: Metric Tons Metric Tons 1926......................... 172,881 1929....................... 271,520 1927......................... 184,557 1930....................... 277,146 1928......................... 269,324 This oil was all produced by the Anglo-Egyptian Oilfields Ltd., a constituent corporation of the Royal Dutch Shell group. During the year 1930 the Egyptian Government was engaged in geophysical prospecting of reserved areas along the Red Sea coast. Other Countries Soma1iland.—A geological survey of Somaliland was undertaken by the Somaliland Petroleum Co., Ltd., a subsidiary of the Royal Dutch

Jan 1, 1931

By C. E. Birchenall, H. M. Schadel

Vapor pressure of silver over silver-gold alloys has been measured over a range of temperatures for four compositions. Orifice effusion has been compared with electromotive force measurement as a means for determining thermodynamic activities in these solid metallic alloys. Correlated activity coefficients are given for silver-gold alloys for the temperature range 200' to 1000°C. SOUND development of a technique for the measurement of some property of matter requires a comparison with other recognized procedures which have been used to measure the same property. Such a check is especially useful if the assumptions on which the applications stand are basically different for the two methods. Agreement in the results tends to confirm both sets of assumptions. The electromotive force method for determining thermodynamic activities depends upon the reversibility of the electrode processes and a knowledge of the valence states involved. The orifice effusion technique of determining vapor pressures requires that certain mean free path conditions be met, that the state of association of the vapor be known, and that efficient collection of vapors be maintained. Thus the requirements are quite different in nature. Although procedures often exist by which the fulfillment of these conditions may be tested internally, agreement of thermodynamic activities for a single system obtained by both methods constitutes a more severe test of the assumptions. The binary alloy system silver-gold is excellent for this purpose for several series of emf measure-

Jan 1, 1954

By Kenyon E. Richard, James H. Courtright

SILVER Bell is situated 35 airline miles northwest of Tucson, Ariz., in a small, rugged range rising above the extensive alluvial plains of this desert region. Its geographical relation to other porphyry copper deposits of the Southwest is shown on the inset map in the lower left corner of Fig. 1. The climate is semi-arid. Altitudes range within 2000 and 4000 ft. Opening of the Boot mine, later known as the Mammoth, in 1865 was the first event of note in the district's history. Oxidized copper ores containing minor silver-lead values were mined from replacement deposits in garnetized limestone and treated in local smelters. Copper production had approached 45 million pounds by 1909 when the disseminated copper possibilities in igneous rocks were recognized. Extensive churn drill exploration carried out during the next three years resulted in partial de- lineation of two copper sulphide deposits, the Oxide and El Tiro. Although the then submarginal tenor discouraged exploitation of these disseminated deposits, selective mining of orebodies in the sedimentary rocks continued intermittently until 1930, providing a production total of about 100 million pounds of copper.

Jan 11, 1954

By B. C. Craft, T. J. Johnson, H. L. Kirkpatrick

Petroleum engineers are displaying considerable interest in the problems of cementing oil wells, especially in the Gulf Coast and California areas, where steep temperature gradients are encountered and where wells are being drilled to greater depths. Deep drilling, that is, at depths in excess of 7000 ft., has been undertaken in these areas only in the last few years and with this trend oil-well cementing requires more technical treatment. It is not the purpose of this paper to describe the scope and application of cement operations in the oil industry or to give the standard specifications, methods of sampling and testing of portland cement. The various testing methods have been described by the American Society for Testing Materials1, Uren2, Tickell and Wankowski3 and Rakestraw and Parsons4. The latter authors (pp. 50-58) have also described in detail the methods of cementing. The authors realize that it is impossible to reproduce in the laboratory the scale of forces and dimensions that exist at great depths, but an attempt has been made to scale down these dimensions proportionally. The selection of problems to be studied was based largely upon the practical questions asked by several of the largest operators in these fields. All cements used in these experiments met the specifications of the American Society for Testing Materials.

Jan 1, 1935

By G. S. Hume

Three provinces in Canada—New Brunswick, Ontario and Alberta— produce oil and gas in commercial quantities. In addition a small amount of oil is being produced and refined in the Northwest Territories at Norman on the Mackenzie River. The production at Norman is derived from two wells drilled by Northwest (Imperial Oil) Co. in 1920 and 1923. The refined products of the oil are used locally in connection with mineral developments on Great Bear Lake. The production of petroleum by provinces and the consumption of natural gas are shown in Table 3. In addition a small amount of natural gas is produced in the southwestern part of Manitoba from shallow wells for local use. Tables 1 and 2 give detailed information. The greatest drilling activity in 1933 in Canada centered around the southern end of the Turner Valley field, Alberta. In addition to several wells previously commenced in this area, eleven new wells were begun. There were three completions to the Paleozoic producing zone in 1933 in the southern part of Turner Valley and one well was abandoned as a result of being off the favorable structure. Of two wells completed in

Jan 1, 1934

By George H. Ashley

It has been said that the Pittsburgh bed is the most valuable single mineral deposit yet known to man. The figures in Table 1 are presented in substantiation of that claim. Production and Value In order that the figures of Table 1 may have any weight, a statement must be made to show how they were arrived at. Because, to the writer's knowledge, no accurate separate figures ever have been kept of the production and value of the Pittsburgh coal bed, the states will be considered separately. Pennsylvania Accurate figures are obtainable for Pennsylvania for recent years because recent reports of the Pellnsylvania Department of Mines show the production from each mine and the bed worked at each mine. For recent years, therefore, it is only necessary to list the mines working in the Pittsburgh bed and add up their production. The value was obtained by treating each county separately, applying the average price for the county to the production of Pittsburgh coal in that county. Unfortunately for great accuracy, while production figures for individual mines are available for many years, the name of the bed being

Jan 1, 1938

By A. M. Gaudin, W. D. Charles

IN flotation lime is used to depress pyrite. For this purpose it is preferred to caustic soda. The low cost of lime and the widespread availability largely account for this preference. However, there is some evidence' that pyrite is more readily depressed by calcium than by sodium ions at the same pH. To measure the difference in adsorption of calcium and sodium, which is thought to lie at the basis of the differences in depressing action, radionuclides of calcium and sodium have been used. The experimental work has included an evaluation of the effect of dissolved oxygen, of the concentration of calcium or sodium, of the concentration of hydrogen ion, and of the anions present. Preliminary work in the investigation entailed preparation of the pyrite, development of a technique for counting pyrite coated with Ca and Na, the radionuclides used, and development of an apparatus to study the adsorption of calcium and sodium on pyrite. The main experimental work included calcium adsorption and sodium adsorption studies detailed below. The following are the most salient observations made during these experiments. Oxygen in solution increases the adsorptive power of pyrite for calcium

Jan 1, 1954

By Byron S. Gottfried

This paper describes a comprehensive computer program, developed under the joint sponsorship of the U.S. Environmental Protection Agency and the U.S. Bureau of Mines, that simulates the performance of coal preparation plants. A typical plant configuration may include several different washers, crushers, and screens as well as stream blenders and stream splitters, interconnected in whatever manner the user may specify. The program will predict the mass and energy yields of each unit and the properties of each flowstream (weight, ash, pyritic sulfur, total sulfur, and energy distributions), provided the feed properties and appropriate values for various control parameters are given. The program is used to assess washability characteristics of different coals, to determine the effectiveness of different plant operating conditions, and to compare the performance of various plant configurations. A brief description is given of the methods used to carry out the calculations for each type of unit. Results of some calculations are also presented. These results illustrate the versatility of the program for analyzing both simple and complex plant configurations. The paper concludes with a description of other accomplishments and future plans.

Jan 1, 1977

By William S. Dershowitz

INTRODUCTION Numerical methods commonly used in rock mechanics, such as finite element, displacement discontinuity, and boundary integral equation methods, offer solutions to problems which can be described by differential equations subject to boundary conditions. These numerical methods use approximations leading to solutions in terms of matrix algebra and numerical integration. Many rock mechanics problems which are beyond the scope of such approximations can be treated effectively by application of techniques developed in the field of artificial intelligence (AI). Among the possible applications are: site characterization (Duda, 1975), geological interpretation (Smith and Baker, 1983), solution of problems involving rock joint networks, and underground construction. Each of these applications utilize particular features of Al. Here we shall present results of AI applications which utilize primarily search and to lesser extent learning or pattern recognition. Specific examples presented are in the field of rock fracture network problems and underground construction. ARTIFICIAL INTELLIGENCE Artificial intelligence techniques attempt to achieve human-like reasoning and learning capabilities. This reasoning capability is valuable in applications where repetition, complexity, or tediousness makes human-like intervention impractical. In rock mechanics this occurs, for example, in stochastic rock mass modeling applications where some complex decision-making is required for each of a large number of iterations.

Jan 1, 1984

By CHARLES F. RAND

PRESIDENT CHARLES F. RAND,1 NEW YORK, N. Y. PAST PRESIDENTS CHARLES KIRCHHOFF,1 NEW YORK, N. Y. JAMES F. KEMP,2 NEW YORK, N.. Y. FIRST VICE-PRESIDENT BENJAMIN B. THAYER,1 NEW YORK, N. Y. TREASURER GEORGE C. STONE,1 NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER. W. RAYMOND, NEW. YORK; N. Y. SECRETARY BRADLEY- STOUGHTON NEW YORK, N. Y.

Jan 2, 1914

By E. A. Holbrook

LOCAL yearly taxes levied on bituminous coal lands in Pennsylvania have become a cost of first importance to the coal industry of the State. In Pennsylvania there is no State tax on real estate, but local taxation of real estate furnishes the greater part of the revenue necessary for the small governmental unit, as counties, townships, boroughs, and local school, road, and poor districts. Coal in place in the ground, whether or not title thereto has been severed from ownership of the surface, is assessed as real estate and on its supposed sale or market value. There are eight classes of counties in Pennsylvania, based on population; in populous counties of the first, second and third class, assessments are made by a county board appointed by the county commissioners and are fairly uniform throughout the county. In counties of the fourth to the eighth classes inclusive, property assessments are made by property assessors elected by and for each township within a county. In these counties the board of county commissioners acts as a board of equalization and review to hear appeals. In most counties, therefore, where there is a large unmined reserve of coal, assessments on that coal vary for each township, irrespective of the fact that the coal bed is continuous under many townships.

Jan 1, 1933

By A. V. Pegler, R. C. E. Bray

The purpose of this study is to determine the distribution of stresses in a particular portion of the ore body of an operating mine. DESCRIPTION OF GEOLOGY The ore body of this base metal mine is a lenticular mass of copper-zinc-iron sulfides, enclosed in a drag-folded quartz mica schist. The schistose host rock has steep dip which varies from north to south and an east-west strike. The drag-fold plunges eastward at about 35º, and this gives a rake of similar inclination to the bottom horizon of the ore zone. The core of massive sulfides is surrounded by an irregular envelope of disseminated sulfides in the schist, so that stope walls are comprised, in most cases, of strongly foliated schist. Adjoining the schist on the south is competent gneiss, while instrusive into the schist in a direction nearly parallel to the foliation is a series of discontinuous quartz diorite dikes, whose contacts with the schist often prove to be lines of weakness. Coarse to fine-grained pegmatites of irregular dimensions are a second type of intrusive associated with the ore body. These dikes generally strike north-east and dip westerly at about 65º. They therefore intersect the schist at an obtuse angle. The dikes are considered to be older than the massive

Jan 1, 1972

By O. N. Carlson, K. E. Solie

The brittle-ductile transition temperatures of single and poly crystalline chromium metal were studied as a function of nitrogen concentration and chromium nitride distribution. It was observed that In recent years there has been an increasing interest in chromium-base alloys for high-temperature applications. The principal disadvantages, however, have been the difficulties of fabrication and the design problems associated with a material of such limited ductility. Various studies have been the effects noted in the poly crystalline material are essentially reversed in the single crystals. These observations are discussed in terms of existing theories for the brittleness of chromium. conducted recently directed toward a determination of the cause of this brittleness and to find ways for minimizing its effects. Allen et al.,' Wain Abrahamson and rant,' and weaver4 have carried out studies on the effects of interstitial impurities on the brittle-ductile transition of chromium metal of various degrees of purity. These investigations have shown that oxygen has little or no effect on the transition temperature of chromium in all conditions studied but that carbon increases the transition temperature under all conditions tested. Nitrogen was found to increase the transition temperature in the wrought condition and in the quenched or cast conditionS but reportedly has no effect in the furnace-cooled condition.

Jan 1, 1964

By R. W. Nelson

Methods for determining permeability presented by W. D. Kruger3 in a paper entitled "Determining Areal Permeability Distribution by Calculation" have considerable merit. They can be expected to contribute significantly to analysis of flow in heterogeneous systems. Some rather subtle yet important conditions must be met, however, to assure that the computed permeabilities are correct. The conditions which insure a unique permeability distribution may have been overlooked in the method as proposed and presented in the subject paper. The subtlety of the special requirements may permit good agreement between computed and measured pressures in the reservoir; but the computed permeability may still be in error. The general theory and discussion of the requirements for a unique determination of the permeability distribution are presented elsewhere in more detail.7'8 Accordingly, only major features will be presented here in the notation of Kruger. GENERAL DESCRIPTION OF REQUIREMENTS A brief mention of the route to be followed in showing the special requirements may be helpful. The equation to be solved is a quasilinear, first-order, partial differential equation in the unknown permeability. This equation can be solved through an extension of Lagrange's method by reduction to a system of subsidiary ordinary differential equations. Through consideration of the identity of one of the Lagrange subsidiary differential equations with the stream function, a special interrelationship can be shown. The interrelationship has special significance with respect to the boundary condition. If the boundary function satisfies part of the subsidiary differential equation, no unique solution for the permeability distribution exists. In the physical problem this requirement for uniqueness indicates that the permeability measurements used as a boundary condition can not be along a stream tube. The boundary condition must be along a line, or series of lines, which completely traverse the region and pass through every stream tube.