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By Paul H. Johnson

Chemical mining may be defined as the use of chemicals in extracting metal values from in situ broken or unbroken ores within a mine. The present means for the generation and regeneration of sulfuric acid or sulfuric-ferric sulfate solutions are inadequate for most applications. This report describes a pressure oxidation process for the generation and regeneration of these solutions from pyrites and spent iron sulfate leach liquors. While recent mining developments such as solution injection, caving, and conventional and nuclear blasting, have provided new and better means for the per-colation of leach solutions through rock masses, little has been done to reduce cost and improve the quality of the leach solutions that are required. A leach solution for chemical mining should meet certain requirements. It should be 1) inexpensive on either a small or large tonnage basis, 2) capable of selectively leaching the desired ore minerals contained in a particular ore, 3) of the proper strength or quality to do the job of leaching in an underground environment and 4) amendable to simple and inexpensive metal recovery steps. It is also important that the capital investment be low for the solution generation and; or regeneration plant.

Jan 8, 1965

By Bai Shiwie, Li. Guangyu

This paper presents the study in situ on stress field of rock mass in a large dam site. By means of two different measure instruments and the method of stress relief, a lot of measure in situ has been done, including stress measurement of three dimensions at ten points and two deep-hole stress measurements in the perpendicular boreholes which are 59.4m and 53m deep seperately, and the basic accordant results corresponding two methods have been got. In the process of the deep-borehole stress measurement we got the stress value in critical state in which cylindrical core would become core-disking in the high stress area, which was first got in the world. The maximum principal stress was up to 650 kg/cm2. The stress value obtained by test and the thickness of rock disks all basically accord to the analysis by mechanical mechanism of core-disking The plane linear elastic finite element analysis has been completed. Results of inverse calculation all ac- cord to the measurement results in four different positions. The whole outline of the stress field of dam site was delineated clearly.

Jan 1, 1982

By William Y. Warren

Messrs. Thomas & Cross, having leased from the Akron Cement Company from twelve to fifteen acres of abandoned cement-tunnels and chambers, for the purpose of propagating mushrooms for the market, commenced operations about a year ago, and are now beginning to furnish mushrooms in quantities to the local markets of Buffalo and Rochester. The quarries, or, more properly, the mines, of the Cement Company are located at Akron, Erie County, PIT. Y. The cement-rock occurs in a stratum about 71/2 to 8 feet in thickness, which is overlain by from 1.5 to 25 feet of limestone and flint-rock. There is a gentle rise from the opening of the tunnel inwards, giving a natural drainage and leaving the chambers comparatively dry. The roof is good and is supported by pillars and heavy timbers. The mushroom-beds are located about 300 feet from the opening of the tunnel, and are made in the form of mounds about 3 feet by 12 feet, at the base, and 24 feet high, giving to the chambers the appearance of a subterranean graveyard. Many experiments have been made to determine the best form for the beds, and the mound

Jan 1, 1889

By T. A. Read, M. S. Wechsler, D. S. Lieberman

IN the formation of martensite in steel, it has been observed that the habit plane does not change continuously as the alloy content is varied. Instead, it appears that discrete habits correspond to certain ranges of composition. Greninger and Troiano' found that in low-, medium-, and high-carbon steels, the habits are approximately (1l1), (225), and (259), respectively.* The work of Mehl and Van Winkle2 indicated that the change from the (225) to the (259) habit is fundamentally a consequence of the lower transformation temperature rather than the higher carbon content. Also, Otte and Read3 observed that the habit plane orientation for a chrome-carbon steel scattered within a cone of semivertex angle of 5 deg, which was outside of the experimental error in the determination of the habit plane. These observations suggest the importance of investigating what factors in the crystallography of the formation of martensite account for the several types of habit and the inherent scatter in the precise orientation of the habit plane. A theoretical treatment of the austenite-martensite transformation has been given,4 which considers the total transformation distortion to be composed

Jan 1, 1961

By S. Feuerstein, J. M. Galligan

SURFACE effects in the deformation of metal single crystals have been noted by a variety of workers.&apos; A large majority of these experiments have used surface roughening or a second chemical constituent at the surface. We performed the following experiment to see how the presence of a fine polycrystalline layer influenced the stress-strain behavior of single crystals of zinc. Spherical single crystals oriented for single slip were acid-machined into cylindrical dumbbell-shape shear specimens having a gage length of 3.2 mm and a cross section of 20 sq mm. The crystals were then deformed varying amounts at the surface of the gage section with emery paper. Following this treatment, the crystals were heated for approximately 8 hr at 200°C. This resulted in a polycrystalline surface layer, with an observed grain size of approximately 1/10 mm in diameter. Deformation of these crystals was undertaken at 78°K in pure shear, the shear direction <1120> lying in the basal plane. The deformation apparatus has been described elsewhere.2 The presence of a polycrystalline layer markedly raises the first observed plastic deformation, as can be seen from Fig. 1. This yield stress is then followed by a region of low work hardening comparable to that observed in shear tests on similar untreated zinc single crystals. However, the extent of easy glide is quite seriously curtailed, and is followed by a more rapid increase in work hardening, reminiscent of Stage II observed in the deformation of fcc crystals. The higher yield can probably be attributed to the difficulty of penetrating the grain boundaries by dis locations from sources interior to the boundaries. If we associate this yield stress with this breakthrough, then we might expect that more dislocations would be trapped in the crystal than is normally the case. If there is an increased density of trapped dislocations, this could lead to an increase in the amount of trapping with increasing strain, giving a larger strain hardening in the crystal. Although other explanations can be given, it is quite tempting to characterize the region of increased work hardening as a manifestation of Stage II-type deformation. This seems reasonable if the polycrystalline layer is quite efficient in holding up a large number of dislocations. In zinc crystals, since it is well-known that the slip distance can be as large as the specimen dimensions, one would only expect to entrap a large number of dislocation with very large crystals or by applying surface layers. If this interpretation of increased strain hardening is correct, it might present a method of studying Stage II in single crystals of zinc. This research was supported, in part, by the Office of Naval Research (1959). The encouragement and stimulation given by Professor E. R. Parker is gratefully acknowledged.

Jan 1, 1965

By T. E. Leontis

Several publications1-7 during the past few years have demonstrated the markedly greater effect of cerium, as compared to all other alloying elements, in enhancing the strength and creep resistance of magnesium at elevated temperature either with or without the presence of other elements. In the work reported in Ref. 1-6, the cerium was added in the form of Mischmetal, which contains all the rare earth elements in essentially the same proportions as they occur in monazite sand, the principal ore of these metals. Mellor and Ridley7 have presented the creep characteristics at 200°C of magnesium alloys prepared both with pure cerium and with Mischmetal. Up to the present time, however, no comprehensive study of the effect of the various component elements of Mischmetal on the properties of sand-cast magnesium has been made. This hiatus in magnesium technology undoubtedly is associated with the difficulty in obtaining the rare earth metals separately. This investigation provides such a survey, the object of which was to determine which of the elements present in Mischmetal contributes the greatest effect in developing high strength and high resistance to creep at elevated temperatures. Toward this end the compositional variation of these properties has been determined as a function of temperature in the following alloy systems: 1. Magnesium-Mischmetal 2. Magnesium-cerium-free Misch- metal 3. Magnesium-didymiuin 4. Magnesium-praseodymium- lanthanum 5. Magnesium-cerium 6. Magnesium-lanthanum This designation, based on the names of the metals as furnished by the producer, is used throughout the paper in order to avoid the complicated system of listing all the elements present in the more complex alloys. The composition of the metals and the alloys is discussed in detail below. Preparation of Alloys ALLOYING INGREDIENTS The chemical composition of each of the six alloying ingredients used to prepare the alloys reported in this paper is given in Table 1. In each case, the percent total rare earths, percent cerium, percent neodymium, percent praseodymium, and percent thorium were determined in addition to the listed impurities. The percent lanthanum was determined by difference from the total rare earth content and consequently includes the other elements (samarium, terbium, yttrium, etc.) present in Mischmetal. These additional elements, however, seldom amount to more than 1 to 2 pet of the total rare earth content of Mischmetal. The iron content of the Mischmetal is considerably lower than that of the other metals. This grade of Mischmetal is now readily available. The metals are listed in the order of decreasing complexity. Elimination of the cerium from Mischmetal results in what the trade calls "Cerium-free Mischmetal." Carrying the separation a step further by eliminating the lantha-

Jan 1, 1950

By L. D. Jaffe

IT is now well established that quenched and tempered titanium alloys have much better ductility when the quenching is from a two phase a-B structure, rather than from an all B structure. The corresponding microstructural differences, however, have not been shown in previous publications. Accordingly, specimens were cut from a % in. rod of commercial RC-130A, containing 7.9 pct Mn and 0.12 pct C, which had been previously hot rolled, heated 1 hr at 1100°F, and air cooled. (The same heat has been studied by others." 7 Samples about 1/4 in. cube were heated in helium 1/2 hr at 1450&apos; or 1700°F, quenched in brine, tempered in helium 1 hr at various temperatures up to 1250°F, and quenched in brine. They were then sectioned and metallo-graphically examined, using an etchant of HF-HNO, in glycerine. As quenched from 1700°F, the microstructure observed was clear /3. (Probably also present was U, as the hardness was 400 Vhn, but w is not yet reliably revealed by any metallographic technique.) When the /3 quenched alloy was tempered at a high temperature, a precipitated as a grain boundary film

Jan 1, 1957

By J. A. Cordier

USINOR has conducted four blast furnace tests with formcoke made from marginal coals in the pilot plant of HBNPC ("H. B. N." process) in four different blast furnaces of various sizes and with medium and high grade burdens. The tests in which up to 30% of the blast furnace fuel burden was replaced by HBN formcoke yielded good results on furnaces ranging in hearth diameters from 5.6 to 9.5 m. The tests demonstrated that: - the slight increase of pressure drop in the stack did not prevent smooth operation at record production rates with the same blowers - the total coke rate was not significantly affected, but there was a slight increase of the calorific value of the top gas - the hot properties of the formcoke are satisfactory as seen from the samples withdrawn at the tuyeres and tapholes. At the end of the two months test on BE nº 2 of Dunkerque, the hearth was as permeable and clean as with good standard coke. Our conclusion is that HBNPC formcoke made from lean coals is an adequate substitute for conventional coke in the range of 20 to 40% replacement, which is of interest to USINOR.

Jan 1, 1977

By H. J. Levinstein, W. H. Robinson

A method of chemically polishing silver for metal-lographic examination has been developed. The samples are prepared by polishing on 0, 2/0, and 3/0 paper. They are then polished on 600 micro-cut paper, followed by a final mechanical polish on a cloth containing 5µ diamond paste. The samples are then chemically polished in a solution of 100 cc of saturated chromic acid and 5 cc of a 5 pct HC1 solution. The chemical polishing is performed by swabbing with a cotton ball saturated with the solution. During the chemical polishing, the sample is rinsed frequently in running water. Polishing in this manner for 5 min is sufficient to remove the strained material from the previous polishing operations. The amount of material removed is approximately 4µ/min. The surface obtained is flat and free of pits. Fig. 1 is an interference micrograph of a silver surface polished by this technique. If the solution employed is of improper HC1 content, an interference color film will form on the sample. This film can be removed either by swabbing with a cotton ball saturated with ortho-

Jan 1, 1962

By T. M. Allen, W. H. White

THE Greenwood-Grand Forks area of southern central British Columbia, known as the Boundary District, has a long history of mining exploration and production. At the turn of the century this was the premier copper mining camp in the British Empire, its total production amounting to some 20 mil- lion tons. Most of this ore came from the great Granby mines at Phoenix, but the Motherlode mine at Deadwood camp, 6 miles to the west, and several mines in Summit camp, 5 miles north of Phoenix, made important contributions. The large deposits were exhausted in 1918 and the district since has seen only desultory exploration and salvage operations. The orebodies are mineralized skarn zones in limestone members of a thick series of Upper Paleozoic sedimentary and volcanic strata. Chalcopyrite is the primary ore-mineral. Copper carbonates and silicates occur sparingly in outcrops, but the oxidized zone generally is very shallow. Much of the surface is mantled by glacial drift which in most places ranges in thickness from 2 to 15 ft. In some of the hanging valleys, however, the glacial drift may be as much as 100 ft thick and may assume drumlin-like forms.

Jan 1, 1954

By Donald W. Gentry

The recently established SME-AIME Education Board has completed its first full year of operation, and its six constituent committees-Accreditation, Career Guidance, Continuing Education, Educational Statistics, and Scholarship-have been extremely active in identifying and initiating programs to serve the educational needs of the Society of Mining Engineers and its members. The Continuing Education Committee-primarily concerned with the needs and problems associated with providing a continuing education program for SME members-is responsible for: (1) determining the need for short course offerings; (2) developing needed courses, along with new means and opportunities of presentation; and (3) scheduling and evaluating course presentation. In response to this charge, the committee has sponsored two short courses at the SME-AIME Fall Meeting in St. Louis and three short courses at the AIME Annual Meeting in Denver. Its major effort, however, has been directed toward the 1978 SME-AIME Fall Meeting to be held in Orlando, Fla., where 18 days of short-course instruction have been scheduled. A portion of these courses will be presented prior to the meeting, with the remainder to be presented in Nassau, Bahamas, immediately following the meeting.

Jan 7, 1978

By K. Winterton

The effect of a near-saturation unidirectional magnetic field was to decrease slightly the endurance life in Armco iron in the annealed condition. This is expected since the energy-absorbing mechanism associated with domain wall movemenfs is inhibited bv the strong field. THE factors determining failure under dynamic loading are not yet clearly recognized. One of the properties of a metal which might be thought to influence fatigue life is its damping capacity. Foppl1 conducted an alternating torsion test at a frequency of 700 cpm continuously for a period of 3 years, without the test piece breaking or showing any sign of deterioration after 1100 Million cycles of stress; the rate of dissipation of energy was sufficient to maintain the test piece at about 100°C above the ambient temperature. cazaud2 concludes from this, and others follow him, that (&apos;the capacity for dissipation in the form of heat by internal damping is unlimited" and that therefore "damping is not directly related with fracture by fatigue." Future work may necessitate qualification of this rather uncompromising view. It is shown later that in all

Jan 1, 1960

By F. V. Tideswell

THE suggestion, which appears to find increasing favor, that the elementary composition of coals should be used as the basis of their classification, makes it important that our methods of expressing this elementary composition should be refined. It is doubtful whether many published ultimate analyses of coals are accurate within 1 per cent. carbon. Many are probably as much as 3 or 2 per cent. in error in carbon. It is, perhaps, not always realized that the extreme variation in carbon content over the range of bituminous coals is but 16 per cent. An error of 1 per cent. in carbon on analysis corresponds therefore with one-sixteenth of the whole range, an amount which is unjustifiable even for the application to commercial needs of a system of classification based on ultimate analysis. For the purposes of scientific research such limited accuracy is of little value. The object of this paper is to examine one important source of error in ultimate analysis, that due to the occurrence in coal of inorganic material, and to emphasize the need for the quantitative measurements (of carbon more particularly) on coals to be rendered independent of their contents of such material.

Jan 1, 1928

By G. S. Hume

Production of petroleum and natural gas increased in Canada in 1939 principally because of new wells in Ontario and Alberta. Turner Valley The Turner Valley field, Alberta, yielded 7,456,000 bbl. of petroleum in 1939 in comparison with 6,703,548 bbl. in 1938, an increase of 11 per cent. Turner Valley now supplies 96 per cent of all petroleum produced in Canada (Table 1). The Turner Valley field (Table 2) has reached a position where it call supply much larger volumes of petroleum than the Prairie market is capable of consuming. The allowable production is under the jurisdiction of the Petroleum and Natural Gas Conservation Board of Alberta and the daily rate is set from time to time as warranted by the demand. During June the allowable reached a maximum of 27,000 bbl. a day. This, however, was a temporary situation due in part to the completion of a new British American Oil Co. refinery in Calgary capable of processing 5000 bbl. a day and with a storage capacity of about 100,000 bbl. The maximum consumption was reached during the harvest season with

Jan 1, 1940

By G. S. Hume

Production of petroleum and natural gas increased in Canada in 1939 principally because of new wells in Ontario and Alberta. Turner Valley The Turner Valley field, Alberta, yielded 7,456,000 bbl. of petroleum in 1939 in comparison with 6,703,548 bbl. in 1938, an increase of 11 per cent. Turner Valley now supplies 96 per cent of all petroleum produced in Canada (Table 1). The Turner Valley field (Table 2) has reached a position where it call supply much larger volumes of petroleum than the Prairie market is capable of consuming. The allowable production is under the jurisdiction of the Petroleum and Natural Gas Conservation Board of Alberta and the daily rate is set from time to time as warranted by the demand. During June the allowable reached a maximum of 27,000 bbl. a day. This, however, was a temporary situation due in part to the completion of a new British American Oil Co. refinery in Calgary capable of processing 5000 bbl. a day and with a storage capacity of about 100,000 bbl. The maximum consumption was reached during the harvest season with

Jan 1, 1940

It is too late to gloat over the fact that minerals have furnished 67 per cent of the primary wealth of Pennsylvania. It is high time that Pennsylvanians do some constructive thinking in terms of the present and future with regard to the remaining mineral heritage.1 The discovery of a deposit of pyrophyllite in the South Mountain region of the Cumberland Valley indeed emphasizes the increased importance of a more exact inventory of the metal and mineral resources of Pennsylvania. Active geological work and research have been in progress for many years, but the surface has been little more than scratched. The results obtained thus far in survey and research have been extremely beneficial to the Commonwealth and a fundamental hub of its industrial development. But these activities are wholly inadequate in the face of rising demands for the future. The need for an accelerated program to continue a study of Pennsylvania&apos;s mineral resources on a more intensive scale was never more acute.2 In part, this has been caused by the insatiable demands of industry. It has been caused also by wasteful use and ignorance.

Jan 1, 1950

By S. K. Kawatra, R. A. Seitz

Various mathematical models and expressions to describe the behavior of a hydrocyclone have been presented in the literature (Lynch and Rao, 1977; Plitt, 1976; Plitt and Kawatra, 1977). Two of these models, by Lynch (1977) and by Plitt (1976), have been extensively used for process control studies (Kawatra and Thayer, 1879; Seitz and Kawatra, 1984). However, neither of these models relates the fineness of grind in a hydrocyclone overflow to the corrected efficiency curve of a hydrocyclone. If such a relationship were available, then one could relate fineness of grind to the operating variables using equation (1) or (2). A plant metallurgist is interested in knowing the fineness of grind rather than the dso(c) of a hydro- cyclone. As a consequence, several empirical relation- ships between fineness of grind and hydrocyclone operating variables are available. These relationships (Fewings, Wickham, and Wiseman, 1979; Manning, 1978; Watson, Cropton, and Brookes, 1970; Watts, Thompson, and White, 1978; Wiegal, 1973) have only a limited relationship with each other and have met with varying degrees of success. The object of this paper is to develop a fundamental relationship between fineness of grind and the efficiency curve of a hydro- cyclone

Jan 1, 1986

By C. R. Boyd

This section is about fifty miles in length, extending from the semi-magnetic and brown iron-ore deposits, near South Fork of Holston River, on Virginia and Tennessee State line, through Bristol, Tenn., Goodson, Imboden, or Mineral City, and Big Stone Gap, Va., to the Cumberland Mountain, on the line between Virginia and Kentucky. Following a geological section from the southeast for near South Holston River), to the northwest, we encounter, first: The slates of No. III.,* generally dipping southeasterly with a trend of N. 65&apos; E. They ontcrop along the north bank of South Holston River, having a thickness of 375 feet, 260 feet of which, as at Pen Rhyn quarry and the James quarry, southeast of Bristol, is slate of high grade for interior architectural uses. Next northwest is an undulating series, giving surface-exhibits of these slates, alternating with Trenton limestone, for 21/2 miles, to the&apos; line of semi-magnetic red iron-ores and brown iron-ores, of the upper horizon of No. II., generally pitching southeasterly, as though the whole series, including the slate described, formed a great trough, with its middle

Jan 1, 1887

By G. W. Tracy, R. D. Carter

A method based on an approach by Hurst&apos; is developed for calculating water influx behavior. Using this method, superposition calculations may be eliminated. The principal diflerence between this method and that of Hurst is that, over finite intervals of time, constant oil-productton rates are assumed by Hurst whereas constant water influx rates are assumed in the presently described method. By adopting the assumption of constant water influx rate for finite time periods, a method is developed for calculating water influx behavior which lends itself to convenient combination with the material balance equation in the Schilthuis form. Above the bubble point, an equation is given for the explicit step-wise calculation of pressure history for a prescribed oil-production history. Use of this method of calculating water influx behavior should result in a considerable saving of time as compared to superposition calculations when the calculations must be made without using a digital computer. The connection is shown between the method described herein and the method developed by van Ever-dingen and Hursr2 (which requires superposition cal-culations). Also, results obtained using the two methods are compared.

By F. A. Forward, A. H. Ross, J. Halpern

IN treating carnotite ores by carbonate leaching it is often necessary to subject the ore to a prior roast. Among the advantages that may result from roasting are: 1) improvement in settling and filtering characteristics of the ore; 2) destruction of carbonaceous impurities that would otherwise contaminate the leach solution and consume carbonate reagent; and 3) substantial increase in extraction of vanadium, which is usually low when the un- roasted ore is leached. Recovery of vanadium may be an important factor in processing carnotite ores, and the fact that vanadium is usually recovered in good yield by acid leaching has often been an economic advantage over results obtained with carbonate leaching. It has been found that response of an ore to carbonate leaching, following roasting, depends primarily on its composition and on the conditions of the prior roast treatment, particularly with regard to the roasting temperature, the atmosphere maintained above the charge during roasting and cooling, and the presence of certain reagents. These factors, especially the last, virtually determine the extractions of uranium and vanadium attainable by carbonate leaching, as well as the reagent consumption on leaching, whereas adjustment of the leaching conditions has only a limited influence.

Jan 10, 1957