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By John A. Emery, Frank G. Snyder

MINING geology has a threefold objective: to guide prospecting for new ore, to evaluate known orebodies as development risks, and to supply the detailed knowledge of ore structures necessary for more economical extraction. The role of geology in exploration is well established. This article will deal solely with orebody evaluation and the application of geology to development and mining problems as practiced by St. Joseph Lead Co. in the southeast Missouri district, which for many years has supplied approximately 30 pct of U. S. lead production. The primary concern of the present discussion is geology in the district, not geology of the district. The southeast Missouri district, locally called the Lead Belt, includes parts of St. Francois, Madison, and Washington counties. The first recorded mining was about 1720 at Mine La Motte in Madison County on surface showings of lead ore. Later discoveries near Bonne Terre, twenty-five miles to the north, led to extensive prospecting and underground mining. To date the district has yielded well over 8 million tons of pig lead, valued at more than $1 billion. By far the greater part of the lead production has come from an area of 50 sq miles, centering on the city of Flat River, as shown in Fig. 1. Role of Geology in Metal Mining The history of the use of geology in the older metal mining districts follows a simple consistent pattern that may be considered in terms of four distinct phases. Each geologic phase is a response to the economic status of the mining district; each has definite characteristics setting it apart from other phases; and each passes into the succeeding phase as the mining operation gradually exhausts the large, rich, easily discovered deposits and lives upon increasingly smaller, lower grade orebodies that are less easily found. The geologic phases and their major characteristics are as follows: Period of No Organized Geologic Program: During the early history of a great metal district ore is easily found by random prospecting and wildcat drilling. Many small operators are active, as profitable mining can be done with a relatively small capital outlay and a minimum of technical staff. Mining practice consists largely of sinking a shaft on an ore showing and following the ore in sight. When the ore is exhausted or becomes unprofitable to mine, the process is repeated on a new ore showing. The miners become familiar with certain ore habits and use this practical geologic knowledge to guide mining. The method is successful as long as large tracts of virgin mineralized area are available. This phase ends when small-scale mining methods are no longer profitable and the mines become consolidated into the hands of a few operators.

Jan 1, 1957

By J. Mazia, H. Rosenthal

An investigation has been made of residual stress in the head and body of caliber 0.30 cartridge cases. The head was divided into four ring-lie sections which were cut off by a jeweler's saw. Spring-out was measured after a radial cut had relieved the circumferential bending moment. The residual stress corresponding to the observed spring-out was calculated by formulas in which the computed stress was a function of wall thickness. All rings sprang open, indicating compressive stress on the inner wall and tensile stress on the outer wall. The production stress-relief anneal of 475 F. for 45 min. reduced the stress to almost half. The priming and crimping operation, however, again raised the stress, especially in the flange section. The dect of stress-relief heat treatments on residual stresses in the body of caliber 0.30 cartridge cases was investigated by the split-ring method. Although this method did not reveal any large stresses in the body, the neck before mouth anneal was found to contain a computed stress of 30,000 psi. at the surface. This value was reduced to 15,000 psi. in 120, 30, and 15 min. at 400, 475, and 500 F., respectively.

Jan 1, 1945

By M. J. Williams, C. P. Proctor, J. T. Crawford

The purpose of this paper is to present some data and comparisons regarding three types of Rheolaveur plants washing bituminous coal from the Pittsburgh seam. It deals only with the sections that handle coarse coal. The Rheolaveur system consists of launders or troughs in which coal and its associated impurities are conveyed by water. The impurities. being heavier than the coal, settle toward the bottoms of the launders and are drawn off through specially designed openings called Rheo boxes. Fundamentally, each plant consists of straight-sided, flat-bottomed launders of varying width and length, each launder equipped with one or more Rheo boxes for the removal of high-grauity fractions of the feed that are undesirable in the cleaned coal. Each launder has at least two longitudinal sections, the first with a slope of from 11/2 to 4 in. per foot of length, called the classification section. The single-box launder has a classification section followed by a washing section ahead of the box. A two-box launder is a single-box launder followed by a washing section and a second box. The slope of the washing section between the first and second boxes is determined to some extent by tonnage. At the end of the classification section, which may. vary from 8 to 15 ft. in length, the slope abruptly flattens out to a slope of from 92' to 1 in. per foot of length. This flatter section of the launder, called the washing section, may vary from a few feet, in a single-box launder, to 15 ft., in a two-box launder. Raw coal entering the head end of what we choose to call the "primary" launder or launders is pushed down the classification section by a stream of water entering the head end of the launder with the coal. As it strikes the washing section, of lower pitch, the velocity of flow is retarded and the heavier particles of slate, pyrite, bone, etc., take their places on the bottom and are drawn off as they pass over the Rheo boxes. The clean coal, of lighter gravity, remains on the top of the stream of

Jan 1, 1938

By M. J. Williams, C. P. Proctor, J. T. Crawford

The purpose of this paper is to present some data and comparisons regarding three types of Rheolaveur plants washing bituminous coal from the Pittsburgh seam. It deals only with the sections that handle coarse coal. The Rheolaveur system consists of launders or troughs in which coal and its associated impurities are conveyed by water. The impurities. being heavier than the coal, settle toward the bottoms of the launders and are drawn off through specially designed openings called Rheo boxes. Fundamentally, each plant consists of straight-sided, flat-bottomed launders of varying width and length, each launder equipped with one or more Rheo boxes for the removal of high-grauity fractions of the feed that are undesirable in the cleaned coal. Each launder has at least two longitudinal sections, the first with a slope of from 11/2 to 4 in. per foot of length, called the classification section. The single-box launder has a classification section followed by a washing section ahead of the box. A two-box launder is a single-box launder followed by a washing section and a second box. The slope of the washing section between the first and second boxes is determined to some extent by tonnage. At the end of the classification section, which may. vary from 8 to 15 ft. in length, the slope abruptly flattens out to a slope of from 92' to 1 in. per foot of length. This flatter section of the launder, called the washing section, may vary from a few feet, in a single-box launder, to 15 ft., in a two-box launder. Raw coal entering the head end of what we choose to call the "primary" launder or launders is pushed down the classification section by a stream of water entering the head end of the launder with the coal. As it strikes the washing section, of lower pitch, the velocity of flow is retarded and the heavier particles of slate, pyrite, bone, etc., take their places on the bottom and are drawn off as they pass over the Rheo boxes. The clean coal, of lighter gravity, remains on the top of the stream of

Jan 1, 1938

By D. J. Barrett, M. A. Sochocky

INTRODUCTION Summary of Factors Influencing Comminution Circuit Design The selection of an appropriate comminution circuit for a specific ore is one of the most important decisions in the design of a processing plant. The importance is related to the fact that the capital and operating costs for crushing and grinding plant generally represent, as is well known, the major portion of the plant costs. This chapter will, therefore, identify as many as possible of the factors which influence the selection of a comminution circuit. The number of factors which will have to be considered for any comminution project will depend, among other things, on the type of project. If, for example, the project is an entirely new mining development, then most, if not all, the factors identified will have to be analyzed. If the project is an expansion of a developed mining operation or if the new orebody is adjacent to a viable operation, then the existing operation will influence the choice of factors or design constraints which need to be considered. The existing infrastructure or supporting systems may be quite adequate to accommodate the requirements of any expansion or new development. Hence, those factors may not have to be considered. To cover, however, the widest spectrum of projects, the factors which have been identified in this chapter are those which will have to be considered for the most complex of projects, that of developing an entirely new mining operation. The range of factors is as broad as the range of different ore types. Thus, each development must be treated with individualized care. The most important step in the development is the analysis and understanding of the ore characteristics. The hardness of the ore, its abrasiveness, friability, moisture content, grade, mineralization including gangue mineralization, liberation size, chemistry, and other characteristics should be the first to be analyzed in the investigation. The next should be the determination of factors such as plant size, throughput, location, climate, accessibility, and availability of water. The selection of samples for initial bench scale work and bulk sampling (when needed) for further

Jan 1, 1982

By L. C. De Jong, J. F. Shirley, M. L. Campbell

At the Southern Peru Copper operation in Toque-pala, Peru, a new process flowsheet for the recovery of byproduct molybdenite has proved successful in dealing with complex and highly variable ores. This paper describes the process and the functions of each of the chemicals used. The Toquepala concentrator of the Southern Peru Copper Corp., located approximately 720 miles southeast of Lima near the Chilean border, processes a daily 36,500 tons of ore containing between 0.50 and 3.00% copper. The molybdenite content in the ore also varies greatly ranging from essentially nothing to as high as 0.15%. The 1966 yearly averages were approximately 1.20% copper and 0.03% molybdenite. The Toquepala porphyry deposit is a mushroom-shaped ore body consisting of a flat-lying enriched zone of predominant chalcocite with a stem-like extension of hypogene chalcopyrite ore in depth within and around a large breccia pipe.1 The underlying chalcopyrite ore has not been reached; however, due to the presence of a major post orebody fault, predominantly chalcopyrite ore is present in the north side of the pit. Most of the molybdenite occurs either as small, fine granular, pulverulent masses in vugs or empty voids of breccia, or as thin foliated masses and narrow thread-like filling in rock joints and fractures. The normal occurrence of quartz gangue with the molybdenite gives some basis for correlating the molybdenite mineralization to some later periods of silicification. On April 18, 1962, the molybdenite recovery plant at Toquepala went on stream, approximately 27 months after the copper concentrator had been in production. The plant was designed and built by Southern Peru Copper Corp.'s engineering and mechanical departments. The basic method chosen for separating the molybdenite from the copper concentrate was the sodium hypochlorite-sodium ferrocyan-ide process. The selection of this process was based on the results of an extensive testing program performed by the Colorado School of Mines Research Foundation, Inc. and the economic conditions of the area. The originally designed process could never be fully implemented due to a lack of sodium hypo-chlorite and has had to be continually modified to satisfy the requirements of the kaleidoscope of ores from the mine. The three basic problems that plague the operation of any molybdenite recovery plant are all present at Toquepala in large measure. Both the quantity of plant feed and the quantity of molybdenite contained in the plant feed are continuously changing. Even more detrimental to an efficient operation is the fact that the copper mineralization in the feed frequently changes once in every 24 hours and occasionally once a shift. From the point of view of the molyb-

Jan 1, 1968

By G. Sachs, L. J. Ebert, W. F. Brown

INTRODUCTION ISOTHERMAL transformation, or "austempering," of a carbon-containing austenite at elevated temperatures yields so-called "intermediate products." Their structure and properties are, for a given hardness, rather different from those of "tempered martensite" obtained on conventional quenching and tempering.1 Several investigators2,3 have found that for high carbon and slightly alloyed steels the intermediate products formed at temperatures close to that of the martensite reaction possess strength properties superior to those of tempered martensite. The structure of these low temperature, intermediate products is generally acicular (bainite) but clearly different from that of martensite. However, at higher austempering temperatures, between 1000 and 1300°F (540 and 700°C) carbon steels were found to exhibit a rather low ductility.4-5 Thus notch bar tensile tests showed the ratio between notch strength and regular tensile strength to decrease with increasing austempering temperature. For ductilities below a few percent this notch strength ratio is a measure of ductility, according to investigations on low alloy steels.6-7 Furthermore the presence of intermediate products formed unintentionally on quenching was considered as responsible for the low ductility and impact energy of some heat treated steels.8 These intermediate products could result from partial transformation at the so-called "nose-temperature" where the rate of the transformation is a maximum. Tempering improved such mixtures of martensite and intermediate products, their properties approaching those of tempered martensite of equal hardness. The following investigation constitutes an attempt to determine certain strength properties of a partially austempered and subsequently quenched low alloy steel, namely, a chromium steel (SAE 5140). The structures formed by such a treatment should consist of a mixture of intermediate products formed on austempering and a martensite formed on oil quenching from the austempering temperature. It was intended, by varying the austempering time, to vary the quantity of the intermediate products between zero and 100 pct. The austempering temperature of 860°F was selected after extensive preliminary tests close to the nose-temperature. Austempering at this temperature yielded an acicular intermediate product. Additional tests under less exacting conditions were made for an austempering temperature of 950°F where the intermediate product appeared to be very fine pearlite. To determine the effects of tempering on structures containing various amounts of

Jan 1, 1948

NEW MEMBERS The following list comprises the names of those persons who became members during the period of Aug. 10, 1917, to Sept. 10, 1917. ADKERSON, J. CARSON, Mgr., Stockwood Realty Corporation, Inc. Woodstock, Va. ARAKAWA, EIJI, Min. & Met. Engr., Min & Met. Dept., Imperial Univ., Kyoto, Japan. BAINS, THOMAS MELLOR, JR Major, Officers' Reserve Corps, Presidio, Cal. BARTON, Louis ARTHUR.. , . Vice-Pres., Adbar Development Co., Dewed, Minn. BLACKSTONE, ALEXANDER J....Asst. Engr., Honiestake Min. Co., Lead, SO: Dak. BOGARDUS, CHARLES EUGENE, Assayer & Chem., Bogardus Testing Laboratories 90 Columbia St., Seattle; Wash. BOISE, DAVID WELLS Chief Clerk, Chino Copper CO., Burley, New Mex. BREEDING, FRANK OWEN Assayer, Eden Min. CO., Bluefields, Nicaragua. BRUYERE, ALAN, Petroleum Geol., Producers' Oil CO., Box 96, Shreveport, La. BUTTS, ALLISON, Asst. Editor, The Mineral Industry, Lehigh Univ., So. Bethlehem, Pa. CALVERT, CLARENCE E Safety Engr., Anaconda Copper Min. CO., Butte, Mont. CHARLTON, HARRY.... Min. Engr, Commonwealth Edison CO., Taylorville, 111. CLAGUE, HERBERT NADEN, Surveyor.. Duncan, V. l., British Columbia, Canada. CLOSE, FREDERIC BAGLEY The Rampart, Los Angeles, Cal. COLLIER, DAVID HENDERSON, Mine Supt., Thumb, Butte Mines Co., Kingman, Ariz.

Jan 10, 1917

By C. K. Ferguson, J. A. Klotz

This paper describes experimental investigations conducted at the California Research Corporation's model oil well. The first part describes filter loss from several drilling muds through bore hole walls during mud circulation and drill string rotation. The effect of mud properties and drill string rotation with mud circulation is described. Filtration from a bore hole full of drilling mud, not circulating, but under pressure for extended time periods, is also discussed. The second part describes filter loss to permeable formations from beneath a drilling bit where filter cuke has no opportunity to develop appreciable thickness. If potential flow theory is applied to predict filtrate invasion from this hole bottom, targe invasions arc calculated. But model well experimentation shows that filtrate invasion from the hole bottom is controlled by mud particles that penetrate the formation ahead of the bit. This experimentation provides data to estimate the effect of mud particle penetration on fluid loss to formation. The third part presents an estimate of mud filtration during drilling of a well. INTRODUCTION As oil wells are drilled by the rotary method, drilling mud circulates up the annulus between drill pine and well wall. Drillers adjust mud density so that the pressure at the bottom of the mud column is several hundred psi greater than the pressure of reservoir fluid. As a result of this pressure difference, the liquid part of the mud filters into the rock around the bore and mud solids deposit as a filter cake on the well wall. For many reasons the petrogleum industry, within the past 20 years, has spent much money and energy to determine the volume of mud filtrate that enters rock around the well bore and dedicated much research effort to reduce this volume. Among the reasons for attempts to determine the volume of mud filtrate and to reduce this volume are the following: 1. If filtrate damages the permeability of oil sand, the resultant damage to oil well productivity will depend on the distance that the filtrate invades the oil sand; reduction of filtrate volume may, therefore, increase well productivity. 2. Filtrate that penetrates shale sections may cause the shale to swell and to slough into the well bore. Uncontrolled sloughing may stick drill pipe. Reduction in filtrate volume may reduce drilling trouble. 3. Electric log resistivity curves are changed by invasion of a mud filtrate; the change depends on the depth to which filtrate invades. Knowledge of this depth is necessary before resistivity logs can be interpreted accurately. For these reasons, specifications the place an upper limit to drilling mud filter loss are now written into almost all drilling programs. These specifications are based on APT Recommended practice 29, Standard Field Procedure for Testing Drilling Fluids,' which describes a static filtration test operated at 100 psi filtration pressure and at ambient temperature. Although this test is adequate for mud control, it cannot be used to compare filtration properties of different muds. Schremp and Johnson' showed, for example, that mud with a low API filter loss does not necessarily have low filter loss at bottom hole temperature and pressure. Also, no information has been available about the effect of bottom hole mechanics (mild circulation, drill string rotation, and bit action) on mud filtration. This paper discusses filtration data measured in the California Research Corporation's model oil well, which models closely oil well bottom hole geometry and hydrodynamic conditions. The filtration processes that

Jan 1, 1955

By H. H. Smith, G. J. Danek, M. R. Achter

Nickel, Type 316 stainless steel, and copper show decreases in reversed bending fatigue strength with increases in air and oxygen pressure. The leveling off of the log N us log p curve for nickel at 300" and 816°C is discussed in terms of a model in which surface saturation gives rise to a critical pressure. A metallographic study indicated that the effect of environment on crack initiation and growth rates is a function of temperature. It is shown that small amounts of impurities in inert gases may substantially reduce the fatigue strength of nickel. 1n a previous investigation1 of high-temperature bending fatigue in air and in vacuum, reversals in the effect of environment with changes in test conditions were atrributed to a mechanism consisting of two processes acting in competition. One of them, oxidation strengthening, has been demonstrated in a straightforward manner by measuring the rupture strength of a sintered nickel-oxide bond.' The detailed operation of the other process, facilitation of crack propagation by surface absorption of oxygen, is uncertain. Thompson et UZ advanced the possibility that the formation of an oxide layer prevented rewelding of cracks during the compressive part of the cycle, while Wads worth and Hutchings4 further proposed that the reaction of oxygen with atoms at the tip of the crack helped the metal to break there, a possibility which has also been advanced to explain crack formation in creep.5 A difficulty in arriving at a mechanism for this lowering of fatigue strength in air is the inconsistency of some of the data. For example, Wadsworth and Hutchings4 found an approximately linear decrease of log cycles-to-fracture (N) with an increase of log pressure-of-air (p) for copper and aluminum at room temperature, while snowden,' although finding a similar linear dependence for aluminum, observed a stepped curve for lead. Between l0-' and 10"1 torr there is a sharp decrease in the fatigue life of lead with increasing air pressure, but plateaus, signifying no dependence on pressure, are found at higher and lower pressures. If, as discussed elsewhere: these environmental effects arise from the adsorption of gas on crack surfaces, it would be expected that as the pressure is increased a saturation point would be observed, beyond which there is no further effect. To gain further information about the form of the log N vs logp curve, it was decided in the present investigation to repeat this type of measurement at elevated temperature on nickel, copper, and Type 316 stainless steel. An additional object of this program was

Jan 1, 1963

By Gerald Sherman

In the southern field of the anthracite region of Pennsylvania, many of the coal seams dip at angles of 40" to 50" from the horizontal. For transportation purposes, "tunnels" are driven across the coal measures and, occasionally, "rock gangways," beside the seams and parallel with them. The use of gangways driven in country rock appears to be increasing, as they avoid the maintenance of long gangways in coal, which eventually are driven to the colliery boundaries, and permit mining from a number of intermediate blocks without interference. The rock consists of slates or sandstones of moderate hardness, which may range into very hard, highly siliceous, fine-grained conglomerates. In this distinctly bedded formation, the direction of the heading, whether parallel with or across the structure, makes it necessary to distribute the drill holes in a different pattern to break the ground, but does not change loading conditions. In 1932, practically all the mucking was done by hand, and it was the established custom to use four men on two drills for drilling and breaking the ground, and five for loading it out. A driver and mule was needed in addition, to assemble the rock cars at a siding or branching track in the rear, pending their final disposal. This might occupy the driver's whole time, or if the length of haul were short, he might be able to do other useful work. It was thought possible in 1932 to reduce the cost of driving such headings in rock by mechanical loading, and to investigate this subject a scraper loader was used in a section of tunnel then being driven. Operations while driving 195 ft. of this tunnel using a scraper loader were carefully observed. Time studies were made of the loading, and records made of the routine of breaking ground, but not in such detail. Tunnels or gangways in the colliery are 7 ft. high above the rails, by 10 ft. wide, which requires a minimum of 8 ft. in height, broken to allow for rails and ties. This cross section is of sufficient size to permit the use of any one of several types of power loaders, but for this demonstration it was found most convenient to use a scraper loader.

Jan 1, 1937

By R. Sporcic, P. J. Mudra

During the past year personnel of the Roof Control Research Group of the Bureau of Mines designed and developed encapsulated hydraulic cells for measuring pressure changes in coal in situ. Preliminary results from feasibility tests in progress in the laboratory and field indicate that the cells respond favorably to changes in pressures associated with a coal-mining environment. The ultimate objective is to use these cells to obtain engineering information relating to coal bump or coal outburst phenomena. Mining research has experienced a remarkable growth during the past decade and from all indications should surge forward at even a greater pace in the future. This increased interest in mining research has been brought about by the ever-multiplying number of technical problems being encountered by the mining industry in its effort to produce pay-dirt tonnages safely and economically from greater underground and surface pit depths. Among the various divisions in the field of mining research, the study of ground stress has received a large part of the overall attention. Numerous technical papers have been written with regard to ground stress conditions around mine openings and yet the total usable knowledge concerning this subject is extremely limited. Research teams around the world are endeavoring to bridge the gap between theoretical and laboratory approaches and the solution to design problems in the field. The problem of ground stress is not a new one for the coal mining industry. Operators in both eastern and western coal fields of the United States as well as in many foreign countries have long been plagued with a number of ground stress problems, one of which is commonly referred to as the coal-mine bump. This term or phenomenon has been aptly defined by earlier investigators as the violent and sudden failure of coal and adjacent rock. Direct results of such failures have been the loss of human lives and thou- sands upon thousands of dollars of sustained mine damages. In an effort to alleviate the magnitude and frequency of these failures, mine operators have employed and are presently employing various corrective techniques. These include: Inducing failure in heavily stressed areas by augering large-diameter holes into stressed pillars, using extensively yield-able steel arches in both long-term haulage and short-term face entries, backfilling unused or abandoned entries with mine waste to gain additional support, and using systematic pillar coal panel extraction techniques including mechanized longwall mining. The Health and Safety Activity of the Bureau of Mines has for a number of years contributed considerable time, funds, and talent in an effort to define better the ground stress problems associated with coal-mine bumps. As a part of this investigative program, in situ ground pressures are presently being studied in coal mines located in West Virginia and Utah. The description and development of the device being used to measure these pressures is the specific topic of this paper. CHOICE OF INSTRUMENTATION After consideration and evaluation of the various instruments and techniques that are being used by researchers in the field of rock mechanics to detetmine in situ stresses, a simple hydraulic system was selected for detailed investigation. Aside from simplicity, a hydraulic system is relatively inexpensive and also eliminates the need for electricity in its installation and operation. The hydraulic device referred to is, in essence, a simple unidirectional pressure-measuring cell. Hydraulic cells, which had been used for measurement of pressures in hard rock, were investigated but found not entirely suitable for use in coal, particularly since they involved (1) preparation and emplacement of cement grout at the test site, and (2) a waiting period before the cells became operational. At the outset, it was decided that certain design parameters be established. The cell should be simple and inexpensive, constructed of materials readily obtainable and easily built in the laboratory or field by unskilled labor. It was further decided that it was desirable to encapsulate the cell in a suitable mate-

Jan 1, 1963

By T. Reed Scollon

Coal reserves of the Rocky Mountain area are vast and are more than adequate to meet significantly increasing demands in the immediate future. Practically all of the increase in coal demand for the next decade or so will be in the electric power utility sector. All ranks of coal are available in the area, and from a technological viewpoint, all are suitable for electric power generation. Location of economically recoverable coal deposits, location of generating plants with respect to power demand areas and sources of cooling water, and availability and price of other fuels are the major factors which, individually or in combination, will determine the ultimate selection of Western coal deposits to be developed for electric power generation. The low sulfur content of most western coals and the non-urban location of many power plants should tend to minimize problems of air pollution. If projections for nuclear power prove correct, increases in demand for Rocky Mountain area coals beyond about 1980 will depend primarily on the extent of commercial development of synthetic fuel processes. Current research activities on the conversion of coal to liquid and gaseous fuels are promising. Most western coals range in rank from lignite through high-volatile bituminous coals and are particularly amenable to conversion. Vast reserves of Rocky Mountain coals have long lain dormant primarily because of their remoteness from major market areas. Recently, however, innovations in coal transportation and electric power transmission methods, combined with unprecedented demands for electric power in the West, have resulted in large-scale development of some of these coals. In the past few years, announcements of coal mine openings and transportation plans in the Southwest have been filled with superlatives: The Navajo mine in northwest New Mexico is expected to be the largest mine in the country in the near future. The largest single coal agreement ever made provides for coal shipment from northeast Arizona to Nevada via the largest and longest coal-slurry pipeline ever used. An 1100-mile haul of coking coal from northern New Mexico to California by unit train began last year. It is the purpose of this report to evaluate the coal resources of the Rocky Mountain area, and to project their potential utilization. In projecting energy demand levels on a national basis, the Bureau of Mines has developed some rather complex techniques to cope with uncertainties. Using these same techniques, an estimate has been made of consumption of Mountain area coal in 1980. No attempt was made to estimate coal consumption beyond 1980, but new market potentials are discussed briefly. The present and potential coal-producing fields of the Rocky Mountain area are in six states comprising the Mountain Region - Arizona, Colorado, Montana, New Mexico, Utah, and Wyoming. Since approximately 19% of the coal produced in these fields is shipped to the Pacific Region (Washington, Oregon, Cali-

Jan 1, 1969

By F. G. Miller, R. C. McFarlane, T. D. Mueller

During the process of gas storage in pressure-depleted oil reservoirs, it has been observed that in some instances additional liquid oil is recovered and that the composition of the storage gas is materially altered. A mathematical study was made of the dynamic behavior of such a depleted oil reservoir undergoing gas injection. The important variable considered in this study, not included in previously published work, was that of compositional effects on the phase behavior of two-phase flow. Pressure, saturation and component composition profiles were developed for a linear, horizontal and homogeneous porous medium containing oil and gas but undergoing dry gas injection. Special new techniques were developed to overcome the problems of numerical smoothing which arise in the solution of the equations representing such systems. The method of solution includes the development of partial differential equations describing the behavior of the system, representing these equations by finite difference approximations, making certain simplifying assumptions and, finally, applying methods of numerical analysis with the aid of a high-speed digital computer. In an example calculation, results using the mathematical model are compared with field observations made on a gas storage project in Clay County, Tex. This field project involved a depleted oil reservoir used 'for gas storage and gas cycling purposes. As a result of these processes, the reservoir yielded substantial amounts of secondary oil, both in the form of stock tank oil and as vaporized products in the produced gas. The methods derived in this study may be applied to a variety of oil reservoir problems which are dependent on compositional effects. In recent years the number of oil reservoirs being used for gas storage purposes has increased greatly, and there has been at least one published account of additional oil recovery resulting from gas cycling a depleted oil reservoir after repressur-ing with dry gas for storage purposes. Additional oil recovery from oil reservoirs resulting from gas storage operations could become an important secondary recovery process. This is especially true since the use of natural gas in large metropolitan areas continues to increase and more gas storage volume near these areas is needed. These facts provided the motivation for the work reported here. This paper reports on a study of the inter-relations of composition, saturation and pressure changes which occur when hydrocarbon gas is injected into an oil reservoir system. From an understanding of the process, prediction methods may be developed for use in forecasting the secondary recovery products from gas storage operations in oil reservoirs and, consequently, .the economics of such projects can be developed. The process of storing hydrocarbon gas in an oil reservoir and the cycling process both involve the transient multi-phase flow of oil reservoir fluids with changing fluid compositions. There is a scarcity of work published on the subject. One of the first laboratory models developed to study a problem similar to the one posed here was published in 1948 by Standing, Lindblad and Parsons. l They developed a model to study gas condensate recovery by gas cycling, including the effect of heterogeneous reservoir permeability. Their results showed the compositional effects of injecting a gas of known composition into a two-phase condensate reservoir of known composition. A major finding of their study indicated that maximum oil recoveries from gas cycling projects result when low cycling pressures are used. Previous to their work it was generally considered

By Joseph E. Worthington

Many thousands of years ago when our earliest ancestor first swung out of a tree, picked up a rock, and threw it at what he hoped might be his lunch, the minerals industry, in a manner of speaking, was born. It was then a very long step indeed to the primitive metal industry of our early civilizations, for we know that precious metals were accumulated and some metal objects were produced several thousand years ago. Prospecting, or "exploration" to use the modern euphemism, consisted of little more than outcrop examination and the use of a gold pan, and it probably did not change much from our earliest civilizations until relatively recent times. In a general sense, all the early explorers of North America were also prospectors, for mineral wealth was certainly one of the goals of the first pioneers and settlers. The earliest pioneers didn't do too badly either, for they discovered copper and iron in various places in the Appalachians and Michigan, gold in the Southeast Piedmont and many mineralized areas in the Southwest. In most places these were outcropping ores or gossans, and the prospecting was incidental to the arduous task of ekeing out a living in a new land. It was the explosive discovery of rich placer gold deposits at Sutter's Mill in California that caught the public fancy and precipitated the establishment of prospecting as a full-time occupation. After the end of the Civil War in 1865, full-time prospecting became an important occupation and continued as such for almost three generations. Prospectors equipped with picks, shovels, gold pans and four-footed transportation swarmed all over what are now our Western States, discovering thousands upon thousands of mineral showings-and certainly most of today's large mining districts. Our vigorous western mining industry is a tribute to the courage and persistence of these men. The techniques of these picturesque prospectors, however, were essentially the same as those of their predecessors-examination of every outcrop and assiduous use of the gold pan. The great increase in discovery at this time was therefore due to increased activity rather than to different techniques. An important result of this in- creased prospecting was the growth of interest in geology. It was during this period that the U.S. Geological Survey began to grow. Many of the major mining districts were mapped, and geological studies and projections began to have an impact on further ore discovery. Ore search and development gradually became more geologically oriented and the geologist became a fixture in most mining camps by the 20th century. The development of mass-mining techniques in the early part of the century also changed exploration concepts.

Jan 1, 1971

By Rollin E. Hook, Attwell M. Adair

The yield and fracture behavior of recrystallized chromiztm have been studied in order to gain an understanding of the recrystallization embrittlement-rheotropic recovery phenomenon. The duc tile-brittle tensile transition temperature of recrystallized chromium was found to vary from 225 ° to -80°C as the ratio of specimen diameter/mean planar grain size decreased. The applicability of this observation to other bcc metals is briefly discussed. Brittle fracture in recrystallized chromium was found to be initiated predominately from intercrystalline rupture nuclei. Single crystals exhibit a high degree of ductility at 23 "C. The experimental data indicate that grain boundaries play a significant part in the yield and fracture behavim. Pres training significantly reduces the transition temperature, and high temperature aging does not result in re-embrittle-ment until complete recovery or re crystallization occurs. SEVERAL theories have been used to explain the recrystallization embrittlement-rheotropic recovery phenomenon in chromium. Wain, Henderson, and ohnstone' propose a Cottrell dislocation locking mechanism due to nitrogen, and Weaver and Gross and weaver 3 propose a strain-induced precipitation mechanism involving a chromium nitride precipitate. The researches of many investigators seem to leave little doubt that brittleness in chromium is promoted by interstitial impurities. Smith and seybolt4 have shown that the ductile-brittle transition temperature is lowered as the interstitial content is reduced. weaver3 provides evidence for a 150°C reduction in the tensile transition temperature as the nitrogen content is reduced from 20 to 5 ppm. Maykuth and affee' have suggested that the amount and orientation of grain boundary impurities may be responsible for the brittle nature of recrystallized chromium. This suggestion was based on their findings that wrought iodide chromium possessing a fiberous grain structure is ductile in tension at room temperature while a recrystallized grain structure is completely brittle. Previous investigations have not studied this phenomenon sufficiently to determine its cause. Perhaps this has been largely due to previous experimental findings that brittle fracture observed in chromium has been almost entirely transgranular.' In addition McNeil and imb,' who investigated coarse-grained as-cast chromium, describe the point of initiation of fracture as cleavage, close to the (100) plane, near or at grain bound-daries, or at included particles or voids. However, Hook, Adair, and ipsitt found that fracture in coarse-grained recrystallized chromium is initiated by intergranular rupture and then propagates nearly entirely by cleavage. This result, together with their finding that room temperature ductility in bending is observed for single crystals and coarse-grained polycrystalline specimens for which the number of grains through the specimen diameter is small, suggests that grain boundaries may play an important role in the brittle behavior of chromium. The recrystallization embrittlement problem can be resolved into two questions. These are, whether the controlling mechanism is predominately one of crack initiation or crack propagation, and whether brittle fracture is initiated predominately by slip or twin induced intergranular rupture or by cleavage. The following research was designed to study the role of grain boundaries on the brittle fracture of chromium in an effort to resolve these questions. EXPERIMENTAL PROCEDURES, RESULTS, AND DISCUSSION General Procedure. All tensile specimens (except 0.04 in. diam wires) were prepared from 1/4 in. diam swaged rod fabricated from one ingot. Details of fabrication are given elewhere. The results of impurity analysis for the swaged rod and for the

Jan 1, 1963

By Stanley Kesler

The first of two initial 650-mw units of the Paradise Steam Station, located on the banks of the Green River in the south-central portion of the western Kentucky coal basin, is scheduled for operation in late fall of 1962. This plant will be the eighth large-capacity, modern station built by TVA in a series starting with Johnsonville, operated first in 1951. During the subsequent ten years, unit sizes have increased from a capability of 125 mw to 650 mw at Paradise. This new unit will take its place in a power system that serves an area of about 80,000 sq miles with a present installed capacity of over 12,000 mw. Upon completion of the Paradise units and other additional hydro and steam units presently under construction, the system capacity will have reached over 15,000 mw. Projected load estimates indicate that this system will provide a margin of slightly under 10% of dependable capacity above peak demand at that time. One Paradise 650-mw unit at that time will represent approximately 4yc of the total system installed capacity.

Jan 10, 1962

By ANDREW CARNEGIE

Although the noble building provided in New York City by Mr. Carnegie for the United Engineering Society has been pushed to about half-completion, the ceremony of laying its corner-stone was not performed until Tuesday afternoon, May 8, 1906. The stone lies just back of the southeast corner of the building, on the north side-of West 39th Street. Among those present were Mr. and Mrs. Carnegie, Miss Whitfield, the sister of Mrs. Carnegie, Ralph W. Pope, Secretary of the Institute of Electrical Engineers, Frederick R. Hutton, Secretary of the. Society of Mechanical Engineers, Rossiter W. Raymond, Secretary of the Institute of Mining Engineers, Charles H. Haswell, the first Chief Engineer of the United States Navy (1836-1851), now in his ninety-seventh year, John Fritz, of the Bethlehem Steel Company, William H. Fletcher, President of the Engineers' Club, E. E. Olcott, President of United Engineering Society, and other interested friends. After an inspection of the interior of the building, the group formed about the corner-stone, which had been draped with the American flag. The exercises were opened by Mr. Olcott, who appropriately welcomed Mr. Carnegie, and briefly expressed the essential value of the building, saying, in part " The societies to be housed underneath this roof have as their aim the pre¬serving and putting in tangible form of the records of scientific accomplishments so as to avoid the repetition of mistakes. The possibility of finding the records of these results all at one center, so near the great Public Library of our city, will be an inestimable advantage to all professions. It is an occasion of no ordinary moment, therefore, when we can welcome Mr. Carnegie and have him lay for us the corner-stone of this great building which his liberality has provided." Mr. Carnegie responded in happy vein, thanking the committee for their greeting, and expressing his pleasure. in being able to do what he had done to further so worthy a cause. Among other things, he said

May 1, 1906

Jan 1, 1920

By Frank Rieber

The discovery that strongly magnetic bodies localized near the surface of the earth could be detected by the distortion which they produced in the resultant magnetic field marked the beginning of magnetic surveying methods. From an original ability to detect bodies of magnetic iron ore and the like when located very close to the surface, these methods have been extended until today they promise to give much information with regard to the structure of such slightly magnetic material as sedimentary rock containing only a very small proportion of iron.' The recent extensions have been made possible through the development of more delicate instruments, and of methods for their use. From the original compass and dip needle, the design of apparatus has progressed until equipment is typified by magnetic balances capable of measuring the components of the earth's field to an extremely high degree of accuracy. It seems unlikely that the limit of such instrumental development has been reached. Just as the change from compass and dip needle has enabled the location of relatively minor changes in magnetic materials, so additional developments in the direction of increased sensitivity, as well as in greater dependability and constancy of operation, should reveal positively many slight changes which either escape notice in the present surveys or are so small that they cannot with certainty be separated from uncontrollable errors due to inconstant operation of the equipment. The ability to read smaller and smaller variations does not mean, of course, that deductions as to the causes of these variations will be made as accurately and definitely as is possible with the more pronounced anomalies.

Jan 1, 1929