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By F. H. Deily, H. W. Lownie, E. A. Loria, L. W. Ledgerwood, M. W. 207-000-000-012 Mallett, J. E. Eckel

MANY investigations have been made of the residual gas content of iron and steel. Very few, if any, quantitative measurements have been made on the oxygen content of cupola-melted iron.' The fact that cast iron is a complex alloy rather than

Jan 1, 1957

By A. Dorsey Lyon

INTRODUCTION A GREAT DEAL of attention has recently been given to the metallurgy of zinc, and much of that which has been said and written on this subject has been in the nature of a criticism. For instance, we are quite accustomed to hearing it said that the metallurgy of zinc has stood still, that it is antiquated, out of date, etc. We are, however, inclined to agree With George C. Stone1 When he says that, although there have been no such spectacular and radical changes as Were worked in the metallurgy of copper and iron by the introduction of converters, there has nevertheless been a decided and marked progress in the metallurgy of zinc, and especially during recent years. However, it must be admitted that, due to the fact that the chemistry of zinc is so different from that of the other metals, the retort process is the only process by which zinc is produced commercially; and, moreover, that losses which occur in the zinc industry-that is, in the mining, milling, and smelting of zinc ore-are very great, for it is stated' that probably less than 50 per cent. of the zinc mined, even

Jan 7, 1914

By J. Amanat, H. J. Siriwardane

A numerical procedure based on nonlinear finite element analysis has been developed for predicting subsidence profile over longwall mine panels. The developed procedure has been verified by comparing predictions with published field observations at several mine panels. This paper presents certain aspects of predicting subsidence profile over mine panels located in hilly terrain. Analysis of four such cases are presented herein.

Jan 1, 1984

By John S. Bell, J. M. Shepherd

pressure difference of 280 psi measured initially on opposite sides of the major fault in the Hawkins Field led to pressure determinations in the Woodbine sand throughout the East Texas basin. Considering the large area, there is unusually good correlation between pressure losses and points of major withdrawals, these losses indicating that the basin pressure has been materially reduced by withdrawals, primarily from the East Texas Field and secondarily from the old fault-line fields of Limestone and Navarro counties, with the pressure loss varying inversely with the log of the distance from these two main areas of basin withdrawals to the measurement points. Apparently faults located throughout the basin serve as local blocks to continuous pressure gradients. INTRODUCTION The pressure anomalies found in the Hawkins Field, Wood County, Texas,' shortly after discovery have led to an area-wide investigation of the pressure distribution within the Woodbine sand of the East Texas basin. These pressures were obtained by drill-stem tests made for that sole purpose while drilling wildcat wells to deeper horizons. The Woodbine sand of Gulf Cretaceous Age is or has been productive of oil and gas in 42 different fields, with the 28 oil fields currently active having produced 118,000,000 bbl of oil during 1949. With one exception, producing energy for all Woodbine reservoirs has been from water drive provided predominantly by expansion of the tremendous volume of water contained in the Woodbine sand. This producing mechanism was recognized at an early date and was described mathematically by

Jan 1, 1951

By John S. Bell, J. M. Shepherd

pressure difference of 280 psi measured initially on opposite sides of the major fault in the Hawkins Field led to pressure determinations in the Woodbine sand throughout the East Texas basin. Considering the large area, there is unusually good correlation between pressure losses and points of major withdrawals, these losses indicating that the basin pressure has been materially reduced by withdrawals, primarily from the East Texas Field and secondarily from the old fault-line fields of Limestone and Navarro counties, with the pressure loss varying inversely with the log of the distance from these two main areas of basin withdrawals to the measurement points. Apparently faults located throughout the basin serve as local blocks to continuous pressure gradients. INTRODUCTION The pressure anomalies found in the Hawkins Field, Wood County, Texas,' shortly after discovery have led to an area-wide investigation of the pressure distribution within the Woodbine sand of the East Texas basin. These pressures were obtained by drill-stem tests made for that sole purpose while drilling wildcat wells to deeper horizons. The Woodbine sand of Gulf Cretaceous Age is or has been productive of oil and gas in 42 different fields, with the 28 oil fields currently active having produced 118,000,000 bbl of oil during 1949. With one exception, producing energy for all Woodbine reservoirs has been from water drive provided predominantly by expansion of the tremendous volume of water contained in the Woodbine sand. This producing mechanism was recognized at an early date and was described mathematically by

Jan 1, 1951

By R. G. Clay, C. F. Seaman

THE mines of The Tennessee Copper Co. are in the Ducktown Basin, in southeastern Tennessee. The ore is a heavy sulphide consisting principally of chalcopyrite, pyrite and pyrrhotite and in places running as high as 05 per cent sulphur and iron. Operating mines are the Burra Burra and Eureka. Development of the Boyd ore body was started in 1940. Late in 1939 the decision was made to change from fuse and cap to all electric blasting and at the same time electric cap lamps were installed to replace carbide. These changes were made to improve the safety and working conditions in the mines. Both the Bureau of Mines and explosives manufacturers recommended electric blasting as a safety measure. Until that time, electric blasting had been used only for shaft sinking and in places where it was absolutely essential for safety. Very few men had had experience in this type of blasting, as the places where it was required were those that also required direct supervision. It was necessary for the mining staff to work out methods, procedure, and equipment to he used. In this they were ably assisted by representatives of the explosives manufacturers. Many mistakes were made and it is the purpose of this paper to describe the original plan and installation, show the major difficulties encountered, the remedies applied, and present the practices now being followed. Comparison of costs of the two methods will also be discussed. About six months were required to make the change and eliminate fuse and cap blasting entirely. The first electric blasting stations were installed in November 1939 and the last fuse was taken underground in May 1940. A very unusual condition forced the use of fuse for a short time in one heading after May, but that will be discussed later. ORIGINAL EQUIPMENT AND INSTALLATION A power line is generally recommended as a source of current where permanent blasting stations are used. The plan worked out for electric blasting was to tap 220-volt alternating-current lines when they were available and use 250-volt direct current from the trolley wire at all other places. A blasting machine would he available at each shaft for places where there were no regular blasting stations and could he used if a regular station should fail. The equipment decided on was No. 16 duplex reinforced lamp cord for lines to within about 50 ft. of the working place and No. 20 lead wire from that point to the shots. An open double-pole, double-throw switch with slate base was put in the circuit, so connected that the down position would close the line to the shots and the up position would connect it to the line from the power contactor. This switch was located in the circuit as close to the blast as was safe (should the shots explode when it was placed in the shooting

Jan 1, 1942

By C. W. Thompson

The two-way belt conveyor for coal mine service simultaneously carries coal from faces and transports men and supplies into the mine, largely eliminating the necessity for rubber-tired supply and man haulage equipment and the necessity of maintaining additional headings. SINCE 1920 use of belt conveyor transportation has increased steadily, and capacity in tons per hour per unit has increased at about the same ratio. Belt conveyor systems for simultaneous two-way material transportation have been widely discussed, but heretofore have proved impractical for specific operations. Studies of a proposed means of disposing of wash-ery waste on the return trip of a main haulage conveyor, as yet uninstalled, led to the application of two-way belt haulage to Weirton's underground supply and mantrip problems. Except for a single-tracked main haulage entry, Weirton mine is essentially a full-belt haulage operation with attendant problems of supply and man-trip haulage that could not be handled with conventional belt conveyors during the regular work shift. It was necessary, therefore, to maintain rubber-tired haulage equipment and haulageways serving multiple-shift continuous operations. The conventional underground belt conveyor is primarily intended to transport coal from working faces to surface. Belts are usually reversed to haul men to face areas at the start of the working shift or to transport supplies. The two-way belt conveyor for coal mine service is not yet offered for sale as a unit by any manufacturer and must be built on order. This conveyor, with return run traveling parallel but opposite in direction to the outgoing or coal haulage run, permits not only haulage of coal from faces, but simultaneously permits transportation of men and supplies into the mine at any time, see Figs. 1 and 2. This eliminates, to a great extent, the necessity for rubber-tired supply and man haulage equipment and the maintenance of additional headings. Unlike conventional installations the return belt is in the open for inspection and maintenance. It is less subject to edge wear, since it runs on regular troughing idlers, see Fig. 3. The only points where the edge of the belt can rub are at the drive unit and the tail units where improved design should eventually eliminate edge wear entirely. Individual conveyor sections are lighter, since all that is needed is a tubular stringer on each side to carry troughing idlers only, no cover plates being necessary. The return run is carried on an assembly identical to that carrying the coal haulage run. These assemblies are definitely easier to handle and are cheaper than installations for the same length of conventional belt conveyor. The four pipes required for the complete conveyor frame may serve only as supports, or, with proper couplings, may be used for mine water discharge line, pressure line for face spraying, telephone cable conduit, or any other purpose requiring a pipe line, see Fig. 4. Additional expense, if any, for the increased number of pulleys needed to turn the belt over for the return service is more than offset by reduced expense for rubber-tired supply and mantrip haulage. The two-way belt haulage system is confined to a single heading on intake air, isolated from all other headings by stoppings on each side, and open for air circulation only at the main haulage way and at the faces. One additional heading, also on intake air, is maintained as an emergency rubber-tired haulage way, all other headings being center-posted and used as airways only until retreat work begins. This method, of course, can and should be used with any belt conveyor, since it provides two independent intake airways for escape in case of fire on the belt or elsewhere. Belt heading is heavily timbered even under good top conditions and space between the two runs permits center posting for the full length

Jan 1, 1954

By P. G. Dunn

Geologic studies during development at Copper Flat were directed at acquiring the necessary information in evaluating a low-grade porphyry copper deposit. In addition to the geologic mapping and core-logging of a typical exploration project, these studies included: - careful checks on the sampling and assaying, - selection of representative samples used to establish the recoverable amounts of precious metals in the ore, - examination of underground workings driven to provide samples both for metallurgical testing and for assay comparison, - evaluation of plant site and waste dump areas as non-material, including a placer examination of the tailings disposal area, and location of an adequate water supply. All these investigation were carefully documented to provide the necessary data both for the engineering design and, more importantly, for the feasibility studies required for successfully financing the project.

Jan 1, 1985

By Milton E. Wadsworth

INTRODUCTION The purposes of this conference are aimed mainly at the treatment of fine or ultra fine particles in terms of beneficiation and chemical processing of minerals. For this reason the discussion on leaching will be confined to processes which treat slurries rather than those which treat a large variety of low and medium grade materials by vat leaching or dump leaching techniques. This eliminates such hydro-metallurgical systems as solution mining from consideration. This discussion will focus predominantly upon the behavior of fine particles as associated with their chemistry in leach reactors. Four major sub-headings may be pointed to as encompassing the major areas in which research and engineering design activity should be directed. These are: 1) generation of fine particles, 2) heterogeneous kinetics of leaching, 3) solution chemistry, 4) engineering design and control of flow reactors. Each of these topics will be addressed briefly in this presentation to illustrate current developments and future needs. GENERATION OF FINE PARTICLES As will be pointed out more quantitatively in the next section the generation of fine particles has great influence upon leaching systems inasmuch as in most cases the rate of leaching is related to the surface area of the particles involved. This is true for acid or base leaching of oxide minerals as well as a large variety of sulfides which have been considered in commercial processes and which have in the case of copper received increased attention during the past decade. Mean particle sizes of slurries vary broadly depending upon the type of grinding equipment being used. For example, in the agitation leaching of uranium ore the slurry typically consists of particles approx-

Jan 1, 1979

By L. L. Davis

Current research by the US Bureau of Mines to develop technology for improving efficiency and productivity in metal/nonmetal mines is described. The research program addresses a wide variety of problems associated with each of the major categories of mining: underground mining, surface mining, m situ mining, and premining investigations. An overview of the Bureau's research activities is given with emphasis on underground mining. In particular, two innovative and promising concepts currently under development are described: a unique shaft sinking system that uses an impact hammer for rock fragmentation, and a low-profile portable crusher for underground hard-rock applications.

Jan 1, 1982

By William H. Emmons

The problem of the metalliferous veins has always been an outstanding one in the science of ore deposits. In recent years interest has been stimulated by Spurr, who maintains that veins have consolidated from magmas that have densities as great as the densities of ordinary rocks. Lindgren published a noteworthy paper1 in 1926, in which he supports the theory that veins are deposited chiefly by hot waters. Lindgren's paper was discussed by Singewald, Spurr, Kemp, Anderson, Colony, Bateman, Porter and others. The discussion, in the main, was centered on the interpretation of fragments that are included in veins. This paper also treats the problems of fragments in veins and includes a reply to a review by Spurr2 of a bulletin by Larsen and myself3 published by the United States Geological Survey on the geology and ore deposits of Creede, Colorado. Mineral veins containing fragments of the wall rock are common. At many places the fragments are completely isolated, one from the other, and are entirely surrounded by vein matter. It has been stated that the vein matter around the fragments was heavier than the fragments and that the latter were floated in a magma. J. E. Spurr, who is the leading advocate of this hypothesis, 4 urges that normal mineral veins were deposited by solutions heavy enough to float fragments of the country rock, and it is mainly on this relation that he bases his theory that veins are deposited by solidification of magmas. If it can be shown that vein-forming solutions have a specific gravity greater than rock (2.77), one is justified in regarding them as true mag-matic solutions. It is shown later in this paper, however, that at Lead, S. D., water not more highly concentrated than ordinary drinking water is depositing vein matter around fragments of schist and of steel in such a manner that the fragments are completely isolated and completely surrounded by the mineral cement.

Jan 1, 1928

By Luis Emylnn Salas

If the ordinary wet method be attempted for silver-bullion containing tin, much trouble is experienced, varying with the amount of tin present. Even with a percentage as low as 0.05, the end-point is masked by a persistent turbidity, while with amounts ranging from 0.5 per cent. upward, the determination of the exact end-point is impossible, owing to the finely divided or colloidal metastannic acid resisting all efforts to cause it to settle, or to give a clear supernatant liquid. The object of the following experiments was to seek a remedy for these difficulties, and to find the conditions whereby the Gay Lussac method might be applied directly to these bullions. Material containing tin is met with frequently in bullion from Mexico or Bolivia; and tin is carried (sometimes in large quantities) in jewelers' sweeps. 1. A bullion was prepared containing Ag, 74; Cu, 25; and Sn, 1 per cent. A weighed amount was treated by the humid assay-method as if it were an ordinary bullion free from tin. Ten cc. of HNO, (1.21) was added, and the bottle was heated until all traces of

Jan 1, 1913

By James E. Jopling

The county of Marquette, Michigan, includes nearly all the iron-mines that have been worked on the Marquette range, which stretches in a generally western direction from the mines at Negaunee, 10 miles from Lake Superior, to those beyond Michigamme, some thirty miles further. The geographical position of this range, nearer to eastern ports than the other iron-ranges, and its ready access from the lake, gave it for a long time a controlling advantage. The country in which the mines are situated is from 800 to 1000 feet above the level of the lake, and is for the most part broken by steep hills, which rise from 100 to 200 feet; between these the land is rolling or

Jan 1, 1898

By Don Blackmar

THE production of non-ferrous secondary metals has become a large and important industry in the United States, and deals with practically every type of manufacturing concern. Its business is unique in that it generally buys from its customers as well as sells to them, whether they are individuals, cities, corporations, or the United States government. Its operations are of vital importance to the success and prosperity of many of the nation's most important manufacturers; yet there are few industries about which less is generally known by those outside it, whether concerning the magnitude of its operations or the details of its actual technique. The industry itself is to blame for this meager publicity, because its technical men have made few attempts to openly exchange ideas, in spite of the excellent examples set by the iron and steel or the copper and brass industries. Whether this is due to the ancient shroud of secrecy generally supposed to cover smelting operations, or because its technical men actually felt that the industry was too puny to be interesting, is hard to say. This paper will consider its subject in a general way, attempting to show something of the size and importance of the industry, as well as its fitness to do its work well. Attention will be called to the sound economic reasons for the handling of non-ferrous wastes by specialists, and to the often unseen losses of metals and labor which occur when manufacturers reclaim their own metallic wastes.

Jan 1, 1928

By Leonard E. Wood, Yeghishe M. Avedissian

Knowledge of the basic properties of rocks-strength, structure, and permeability-is prerequisite for the success of foundation work for masonry dams, large bridge piers, and tunneling as well as for excavation in rock and special underground construction. Strength of engineering materials depends upon texture and structure as well as the environmental conditions to which they have been subjected. Failure in its widest sense implies the transition of a material from elastic to plastic state (yield strength), from continuous to discontinuous state (rupture strength). The compressive strength of a material such as rock is the stress at which a sample, loaded and unconfined at the sides, fails by rupture. Some of the external factors that control strength of rocks are the nature and type of stress, whether uniaxial or triaxial, compression, tension, or torsion. Another important factor is the rate of stressing-whether constant, impact, or gradually increasing. Of the internal factors, the effect of texture upon strength is obvious. Generally, fine-grained rocks have higher compressive strength than coarse-grained prototypes. Among metamorphic and igneous rocks those with better and higher degree of interlocking of their crystals are generally stronger than the ones with poor or lower degree of interlocking. In sedimentary rocks, the degree and type of cementation has a great influence upon their strength. Structurally, the existence of fissures, cracks, and seams of argillaceous or organic materials in a rock specimen will greatly reduce its strength. Because most rocks are characterized by bedding planes, laminations, or foliations, they are anisotropic in their physical properties and hence compressive strength depends on the orientation of the bedding planes to

Jan 1, 1972

By V. J. Bishop, R. G. Beverly

Recent publicity has focused attention on the hazard of lung cancer among uranium miners. Many mining people feel the danger has been exaggerated. Whether or not this is the case, the industry must thoroughly evaluate this potential hazard and take corrective measures to minimize the threat of radiation after-effects and to maintain the level of radiation in mines within the presently-accepted limit. The measurement and control of radon gas and its solid radioactive decay products, Po-218, Pb-214, Bi- 214, and Po-214, should be the one facet of most concern to uranium miners in any radiation control program. To illustrate the radioactivity involved with small quantities of radon gas, the activity from the decay products of five milliliters of radon gas (imagine a 5-ml vial) would be adequate to raise one cubic mile of air to seven times the recommended maximum working level of 300 [ ] (micro micro curies) per liter. This would be enough radioactivity to raise to the maximum working level a 6 x 8-ft drift which extended around the world 160 times. Obviously, a little radon gas goes a long way.

Jan 8, 1961

By R. R. Sayers

VENTILATION may be defined as the process by which vitiated air of an inclosed or partly inclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level PER CENT. Oxygen 20.94 Nitrogen 78.09 Carbon dioxide 0.03 Argon 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxid, ammonia, ozone traces CARBON DIOXIDE LIMIT For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent. carbon dioxide.

Jan 7, 1926

By Donald W. Gentry

Many firms in the minerals industry are facing enormous capital-equipment requirements for existing operations, planned expansion programs, pollution control systems, etc. Yet, because of existing economic conditions, mining companies find it increasingly difficult to obtain reasonable financing for the acquisition of large, high-cost capital equipment. One way of obtaining the use of mining and other major pieces of high-cost capital equipment is through leasing. The popularity of this approach is evidenced by the growing number of leasing companies, equipment manufacturers, and financial institutions now offering this service to their customers. Indeed, leasing has become a billion-dollar industry, and many commercial banks have developed sizeable portfolios in this area. "Should we buy or lease?" This question eventually comes up whenever a mining company needs additional major capital assets. Unfortunately, many buy-or-lease decisions are made on an emotional basis-rather than on a proper financial evaluation that would yield the…

Jan 9, 1975

By S. Frederick Ravitz

JUDGING from the inquiries that are constantly being received by the Utah Engineering Experiment Station as to the "Why," so to speak, of the flotation process of concentrating minerals, it occurred to me that perhaps a brief statement of the more important theories might interest those who have not followed the technical literature. Like many other industrial processes, flotation has hitherto been developed on an almost purely empirical basis, with relatively little practical contribution from the fundamental chemistry and physics on which the phenomena are based. In fact, its development by the trial - and - error method has been perfected to such a high state that it is becoming generally thought that further important advances can be brought about only by a thorough understanding of the actual mechanism of the process. Natur¬ally, such a complicated process has brought forth numerous theories, most of which have failed to withstand the test of time. It is significant that no theory has yet been advanced which is universally accepted.

Jan 1, 1933

By Robert Lowrie

Nine intermetallic compounds were tested in tension at various temperatures. Seven exhibited extensive plastic deformation at elevated temperatures. Correlations of tensile strength and elongation are attempted with melting (decomposition) temperature, valence electron configurations of the component elements, heat of formation, crystal structure, density, and volume decrease accompanying compound formation. A LTHOUGH intermetallic compounds have been -tX known for many years, the study of their mechanical properties, particularly in tension, is just beginning. The problem has been unattractive because of the well-known, erratic behavior of brittle materials tested in tension. The strong influence of surface or internal flaws as stress raisers in non-ductile materials and the effect of eccentricity of loading in superimposing bending stresses on the state of tension in the specimen are extremely difficult to mitigate and impossible to completely eliminate. Thus, tensile properties determined for brittle materials, such as intermetallic compounds at temperatures low in comparison to their melting points, are at best only general guides to the values to be expected in an ideal test of a perfect specimen of the material. It is, nevertheless, surprising that apparently no attempt was made to follow up the pioneer work of Tammann and Dahl1 in this field. Working with crude apparatus, these investigators succeeded in showing unequivocally that at temperatures sufficiently close to their melting points (from 75" to 400°C for the compounds tested) intermetallic compounds did exhibit plasticity. This was indicated by the appearance of slip lines on the surface of the specimen. No observations of strength were made in these tests, which were of a compressive or indentation type. Rossi2 in 1932 attempted to study the physical and mechanical properties of single crystals of a group of intermetallic compounds. However, he was able to prepare only one material, Cu2Z8,, in the form of large, defect-free, single crystals. Thus, he was able to report only the relative fragility of the compounds at room temperature. He reported one compound, Ag,Zn,, to be somewhat plastic at room temperature and Cu,Si to be friable, the latter in agreement with results reported herein. Although test results are available only in classified literature, it has also been announced that MoSi, possesses some ductility at elevated temperatures." In 1948 and 1949 Savitskii and Savitskii and Baron -ublished their work on the hot extrusion of Mg-Zn, Al-Mg, and Cu-Zn compounds. Under the favorable state of stress existing for this process MgZn, MgZn,, MgZn,, ß (Al-Mg), ? (Al-Mg) and 0 (Cu-Zn) could be reduced by amounts up to 90 pct at elevated temperatures. These authors also report that hardnesses of Mg-Zn compounds decrease from room temperature values of about 300 kg per sq mm to 30 to 50 kg per sq mm at 325°C. They found that alloys consisting solely of one Mg-Zn compound were most resistant to softening on heating, mixtures of a compound and eutectic less resistant, and mixtures of two compounds least resistant. The more rapid softening of mixtures of

Jan 1, 1953