Search Documents

By AIME AIME

EVEN the weather man joined in a friendly conspiracy to make the fall meeting of the Industrial Minerals Division at Rolla, Mo., Oct. 23-25. the splendid surges that it was. Following weeks of rain, the foliage of the Ozarks was still green, merely enlivened here and there by splashes of autumn coloring. In contrast to the tranquil beauty of the School of Mines campus under smiling Indian summer skies, the pace of the meeting was lively. Registration was larger than at any previous meeting and included an unusual number of prominent names and delegates from all over the country. From 125 to 150 were present throughout the three technical sessions, at the Thursday evening smoker, and also at the banquet on Friday; when students trooped in to the technical sessions the audience was augmented occasionally to over 200.

Jan 1, 1941

By G. C. RIDDELL

THE metallurgist, chemist, and physicist are blazing trails that lead far afield. Pushing on into an "Alloy Age" they see a non-ferrous era over- taking iron and steel. Delving into the nature of the physical world, they break down a supposedly indivisible element, hydrogen. Not content with terrestrial problems, they peer back along the cosmic ray into iaterstellar space, glimpsing forces that are, apparently, still busy with the task of atom-making. Mastering and organizing the material and physical, they advance steadily toward that borderland of science where the concept of matter itself seems abandoned, and force is the substance left.

Jan 1, 1930

Thomas T. Read, New york, N. Y. (communication to the Secretary *):—At the meetings of English technical societies it not infrequently happens that, during the discussion of a paper, someone will arise to say that although he highly appreciated the material presented, nevertheless he believed it would have been better if some other phase of the question had been more highly emphasized. Assuming that this form of discussion is permissible in the Institute, I should like to reiterate the point made by Prof. A. J. Moses that conclusive proof of the identity of the minerals in question is an essential feature of the study of ores in this way. This is also expressed by Paul Krusch in his recent valuable paper on the sulphide ores (in which he arrives at conclusions diametrically opposed to those of Mr. Graton), as follows: "The diagnostic properties of the various ore minerals are known to but a limited circle of investigators." Many earlier investigators began the study of ores beneath the microscope by reflected light, but discontinued their work, in most cases, because they were unwilling to undertake the great amount of preliminary work necessary to securely establish a basis for their inferences. It is evident that Messrs. Graton and Murdoch realize that the promised later paper on diagnostic characters will be the more important of the two, but the point should be emphasized to forestall a flood of literature from other investigators who may gain the impression that the brief survey of polished specimens is a vade mecum to incontrovertible conclusions as to any given ore deposit.

Jan 1, 1914

Discussion of the paper Of JAMES JOHNSTON, presented at the New York meeting, February, 1914, and printed in Bulletin No. 85, January, 1914, pp. 107 to 133. CHAIRMAN E. GIBBON SPILSBURY.-I would like to call attention to the fact shown in this paper that less than five years or perhaps seven years ago nobody had thought it possible to cyanide with success silver ores. The cyaniding of silver and gold ores was first of all started in Mexico, and gradually extended to this country in the case of the silver ores alone. The average extraction, I think, for the metals in Mexico, in the case of the silver ore, is less than 85 per cent., whereas here, in the case of a very complex ore, carrying a high percentage of sulphur and arsenic, and other objectionable elements, the ore has been treated so as to extract an average of 95 per cent. of the silver contents of the ore. It is really a phenomenal revolution in the metallurgy of silver ores which has been demonstrated and worked out at the Nipissing mines. GEORGE A. PACKARD, Boston, Mass.-I would like to suggest a slight modification, perhaps, of the statement which is made that no one considered cyaniding of silver ores up to five, or perhaps seven years ago, because in 1897, when I was at Mercur, Utah, one mill near there was operating on silver ores. It did not operate very successfully from a commercial standpoint, because they did not have a great deal of ore, but the extraction, I was told, was very satisfactory, and I am quite confident that it was, because, as suggested by the name, Chloride Point, the ores were silver chloride ores, and of course very easily soluble. Some years before that, in 1892, I made some tests myself. I spent three months making tests on more or less complex silver sulphide ores at Virginia City, Mont., and while our tests on the plain sulphide ores, finely ground, were quite successful, on account of the presence of a small amount of copper we did not work out a satisfactory solution of the problem at that time; although since then a cyanide plant has been erected and for at least eight years these ores have been treated by cyaniding at Virginia City, and the mill is still in operation. The period of five to seven years should, therefore, be modified considerably, in justice to the pioneers in the cyanide processes. REGINALD E. HORE, Toronto, Ont., Canada.-I hoped that there would be metallurgists from Cobalt here to present and discuss Mr. Johnston's paper. In their absence a few remarks from me may help to make clearer to you what they have accomplished.

Jan 6, 1914

By W. Joseph Schlitt, William D. Southard, Bruce P. Ream, Lawrence J. Haug

The operation of Kennecott's Bingham Canyon copper precipitation plant, one of the world's largest, is described. This description includes a brief historical review of precipitation at Bingham and the general layout and operation of the present cone cementation facility. Current practices are based on results of studies undertaken to define improvements needed in each unit operation. These improvements were required to meet changing plant conditions and were implemented primarily within the constraints of the existing facilities. Specific unit operations included were the cone precipitators, the cone discharge thickener, the cone effluent settling basins, and the plate and frame filter presses. As a result of these improvements, loss of precipitated copper decreased and the degree of precipitation increased, raising copper recovery by 9 t/d. At the same time, iron consumption was reduced by 22.5 t/d. Problems in drying the cement copper were also overcome so that a product containing 12 - 15% moisture could be consistently delivered for smelting.

Jan 6, 1979

By William D. Southard, Joseph W. Schlitt, Bruce P. Ream, Lawrence J. Haug

The operation of Kennecott 's Bingham Canyon copper precipitation plant, one of the world's largest, is described. This description includes a brief historical review of precipitation at Bingham and the general layout and operation of the present cone cementation facility. Current practices are based on results of studies undertaken to define improvements needed in each unit operation. These improvements were required to meet changing plant conditions and were implemented primarily within the constraints of the existing facilities. Specific unit operations included were the cone precipitators, the cone discharge thickener, the cone effluent settling basins, and the plate and frame filter presses. As a result of these improvements, loss of precipitated copper decreased and the degree of precipitation increased, raising copper recovery by 9 t/d. At the same time, iron consumption was reduced by 22.5 t/d. Problems in drying the cement copper were also overcome so that a product containing 12-15% moisture could be consistently delivered for smelting.

Jan 1, 1980

Jan 1, 1966

By Charles S. Barrett

THERE is a road into the microscopic realm that has remained untraveled through all these years of intense activity with high-power optical and electron microscopy. The road is worthy of careful scouting by metallurgists and other investigators, for it leads into relatively new country and it makes some areas accessible that heretofore could be reached only by very indirect paths or by the use of imagination. And when the road passes through familiar territory it frequently permits a new view of commonplace things that should prove of value from time to time. An accepted way to interest people in new sights such as this is to present an illustrated travelogue. This I propose to do, using many pictures taken in my recent exploration of this road. In the manner of travelogues, I shall touch briefly upon a large number of different subjects in physical metallurgy and shall, attempt to give an exhaustive treatment of none, for the objective is to provide a means for further research, to interest others in it, and to indicate what appears at the moment to be profitable directions for it to take. The method I shall present involves X-rays, but does not make use of the usual accompaniments of X-ray research such as reciprocal lattices, Fourier series, or the stereographic projection. The method is so simple in its fundamentals that it could have been developed 20 years ago, or perhaps even 30 years ago. It is well to have a destination for our travels, so that when we are through we shall have explored some region of importance, despite our preoccupation with the novel means of transportation and our interest in the sights to be seen along the way. So let us name the Cold Worked State as our destination, and make side trips into the territories known as Recovery, Recrystallization, and Precipitation-hardening. A great many investigations have been made of the nature of cold-worked metal, and a great variety of methods used, many of which are indirect, such as X-ray line intensities, X-ray line widths, calorimetric measurements, and magnetic measurements. Since comprehensive reviews of these investigations have been published in recent years, they need not be discussed here. The investigations that were the direct forerunners of the present work should be first mentioned. In 1931 I became interested in the structure of individual spots in X-ray diffraction patterns.1 When a crystal is placed in the narrow pencil of X-rays in a Laue camera, the spots recorded on the film are not always uniformly black, but may have an internal structure. The meaning of this may be understood from Fig. 1, which represents a narrow beam containing X-rays of many wave lengths ("general radiation") penetrating a crystal in the direction of the arrow and forming a pattern on the vertical film at the right.

Jan 1, 1945

By E. J. KENNEDY

METHODICAL AND EFFECTIVE: thus may be characterized the fall meeting of the Iron and Steel and Institute of Metals Divisions at the Hotel Statler, Buffalo, N. Y., on Oct. 4 and 5. Approximately 200 registered. Interest centered 1111 the technical papers which were keenly followed, with substantial discussion: During the entire week of the National Metal Congress (Oct. 3 to 'i), there were also other sessions of interest' to metallurgists, directed by the America11 Society for Steel Treating, American Welding Society, Production Division of the Society of Automotive Engineers, the Iron arid Steel and Machine Shop Practice Divisions of the American Society of Mechanical En,' the Wire Association and the American Drop Forging Institute. The National Metals Exposition at the 174th Regiment Armory was well attended.

Jan 1, 1932

By H. A. Pearse

NORMALLY, the Britannia ore mixture contains chalcopyrite and pyrite as the chief sulfide minerals, together with minor amounts of gold and silver and a low zinc content. Reduction is accomplished by jaw crushers underground, followed at the concentrating plant by Symons cone crushers, rolls, and ball mills. The standard flotation practice, evolved during several years of experimentation, provided for bulk flotation of the two sulfides, after primary grinding to only approximately 35 mesh, followed by regrinding of the bulk concentrate, with subsequent separation of the chalcopyrite and pyrite to make a marketable concentrate of each mineral. This so-called standard milling practice has previously been described in detail in U. S. Bureau of Mines Information Circular 6619. A modification will he discussed here. In the face of a constantly increasing world surplus of copper and a steadily falling price during 1930 and 1931, it was obviously undesirable to continue unprofitable production of large quantities of this metal. On the other hand, company officials were

Jan 1, 1934

By Roger L. Beals, George A. Tweedy

I. INTRODUCTION. THE results of the cyanide-operations, given in detail in the following paper, show the progress that is being made at the Minas del Tajo. The old pan-amalgamation process, in operation up to and including 1905, while paying a profit on high-grade ores, was no longer able to treat profitably the ores in sight at that time, hence an alteration in the process was imperative. The success of this alteration is eloquently expressed by the following data Pan- Amalgamation. Cyanidation. 1905. 1907. 1903. Tons treated, . . 51,387 53,983 69,300 Value per ton (U. S. currency),. $10.75 $8.39 $8.28 Extraction, per cent., 65.00 88.50 S7.45 Extraction, per ton. .- $7.00 $7.4.; $7.24 Total cost, per ton treated, 6.50 4.311 4.01 Profit, per ton treated, . . 0.50 3.07 3.23.;

Feb 1, 1910

By Georgc E. Collins

SEVERAL years ago, I estimated the total stock of gold in the world to be about a thousand million ounces, of which rather over one-third was available for monetary uses. Robert H. Ridgway has estimated the world's production from 1493 to 1927 as slightly over this amount. Of this total, 1.5 per cent was produced between 1493 and 1850 (before the Californian and Australian goldfields began to flood the world with gold), 331/2 per cent from 1851 to 1900, and 511/2 per cent from 1900 to 1927. Allowing for loss by attrition and permanent consumption in the arts, and for loss of buried treas¬ure, my first-mentioned estimate is perhaps not far from the truth; but my estimate of the monetary stock was certainly too low. Of the total production stated by Rid-way. 28 per cent came from North America. 26.9 per cent from Africa, 1.6.8 per cent from Australasia, 12.4 per cent from South America, and 11.2 per cent from Asia. Excepting that from the African conglomerate beds, the ultimate origin of which is still the subject of controversy, by far the greater part of the total production was derived from alluvials. Weighing all contingencies, it is improbable that any such production as has been made during the last forty years will be repeated in any similar period, if the present price level is maintained. The gold standard today seems firmly established except for temporary digressions. Nevertheless, no well-informed mining engineer will venture to assert the probability that the material for its maintenance throughout future generations can be furnished.

Jan 1, 1932

By ALFRED T. BARR

In certain areas of the New Cornelia pit, considerable secondary blasting is necessary to reduce oversized boulders, formed from primary blasting, to pieces which will pass the 41/2-cu yd dippers on the shovels. Some of the boulders are 'dobied, but when time permits they are blockholed and blasted. In most instances one hole drilled to a depth of 2 to 3 ft and blasted with 1/3 to 1/2 of a stick of powder will break a boulder satisfactorily. Blockholing is normally done by using a jackhammer of the 55-lb class, 1-in. round drill steel, and detachable steel bits, 2-in. gauge when new. A bit change is usually made after the completion of each hole. The use of light drilling equipment in blockholing is desirable, both from the standpoint of safety and ease of doing the work, and when it was seen there was a possibility of using a lighter jackhammer through the use of tungsten-carbide bits and at the same time get at least the same drilling efficiency as with the standard equipment, it was decided to test tungsten-carbide bits. The claims for long life of the bits and footage drilled before resharpening gave hopes of eliminating much of the delay time in changing bits which is unavoidable with the use of steel bits. and thus gain in actual drilling time.

Jan 1, 1949

By Maurice Magee

The Ducktown ore deposits have been known, explored, and mined for 120 years. Eight massive sulfide ore bodies occur in highly folded and metamorphosed graywacke, graywacke conglomerate, mica schist, chloritegarnet schist, and staurolite schist of Precambrian age. The ore deposits are tabular bodies that have been extensively folded, generally conform to the enclosing rocks, but show local complex differences. The ore deposits, ranging in size from 250,000 tons to over 20 million tons, are composed principally of the minerals pyrrhotite, pyrite, chalcopyrite, sphalerite, and magnetite. Gangue minerals are quartz, calcite, actinolite, tremolite, hornblende, garnet, and masses of schistose wall- rock. Three fault systems are present that have influenced ore control and ore body configuration. Hydrothermal effects are evident in wall-rock alteration. Evidence of retrograde metamorphism is extensive in the wall and ore associated rock. Preliminary isotopic age dates have indicated four possible metamorphic events during the Paleozoic Era. Ore genesis is considered to be hydrothermal replacement of receptive beds, predominantly highly calcareous zones, quartzitic zones, and brecciated shear zones. Ore deposition is thought to have occurred during the Devonian Period, with later mobilization and recrystallization of the ore and gangue during Middle and Late Paleozoic times.

Jan 1, 1968

By John Griffen

HYDRAULIC classification as explained by Rittinger and others was largely restricted to conditions wherein the free-falling velocities of the particles were conceived as governing the separations effected (see chapter 9). The laws governing classification under free-falling conditions have been summarized by Chapman and Mott as follows:

Jan 1, 1943

By M. C. Manderson

Abstract-The sharp drop in world phosphate demand that took place in 1975, due to temporarily high prices, now seems to be reversing itself. And prices for both phosphate rock and phosphate fertilizers, which declined dramatically from their 1975 highs, now appear to be bottoming out. This recent price weakness has delayed new mining ventures that had previously been planned for completion by around 1980. While there is ample capacity to supply near-term rock needs, the stage seems to be emerging for a better supply-demand and price environment in the late 1970's and early 1980's.

Jan 1, 1978

By THOMAS LEONBRD WATSON

INTRODUCTION. IN a paper read by title at the Washington meeting of the Institute, May, 1905,1 discussed at considerable length the geological relations, node of occurrence, and the genesis of the lead- and zinc-ores of the Virginia-Tennessee region. The present paper treats of the purely economic phases of the zinc-ores of the district; such as methods of mining the ores, their preparation and treatment. The Albemarle county mines and plant were discussed in the paper referred to above, and will not be considered here. METHODS OF MINING. Until very recently the mining of lead- and zinc-ores in Virginia was limited wholly to the surface belt of weathering. The mode of occurrence and the character of the ores to be mined were such as to demand the employment of methods used in mining secondary concentrated ores. Accordingly, a system similar to that practiced in mining brown iron-ores was employed, being modified to meet the changed conditions. Oxidized or Soft Ores.-Up to the present time practically all the ore mined in the Virginia district has been of the oxidized or soft type;-the silicate, calamine, and the carbonate, smith-sonite; largely the former, which has been localized and concentrated at only slight depths below the surface. Because of the extreme irregularity with which the limestone weathers when stripped of the overlying residual clay, it presents a roughened surface of large and small irregular "chimneys"

Mar 1, 1906

By James T. Wood

Stratigraphy, structure and closure of the Paloma field are discussed, with some details regarding the present state of development. The Paloma anticline, a large dome modified by faults, is the largest single closed dome in the southern San Joaquin valley without surface outcrop or topographic expression. It owes its discovery to geophysics. Of nine wells drilled to the Stevens sand, seven are productive. The ultimate productive area may approximate 3000 acres when the limits of the field are determined. Introduction The Paloma field derives its name from the Paloma school, ½ mile north of what is now the center of the field. The field is 17 miles southwest of Bakers-field, in the south central part of the San Joaquin Valley (Fig. I). The present developed area and its expected extensions are in townships 31 and 32S., R.26E. It is the most southerly of several fields that produce from the Stevens sand zone. The first well to produce condensate was a joint test drilled by the Western Gulf Oil Co. and The Texas Co. near the center of sec. 3, T.32S., R.26E., well No. 54-3. This well was completed on Aug. 31, 1939, at a depth of 10,178 ft. The initial production was 2280 bbl. a day of condensate and 14,750,000 cu. ft. of gas (½-hr. gauge) through a ?-in. bean. Prior to the drilling of this well, the Ohio Oil Co. discovered and developed a small gas field, which embraces a part of three townships about their common corner but lies chiefly in secs. 31 and 32, T.31S., R.26E. The first well was completed on July I, 1934, at a plugged depth of 5239 ft. after having been drilled to 7957 ft, production was found in a 59-ft. zone IIO ft. below the Fourth Mya bed, within the Sari Joaquin clays. Until recently this field was known as the Buena Vista gas field. It is now carried by the Division of Oil and Gas as the Paloma gas field. Production within the Paloma gas field is derived from six wells, producing from several different zones in the interval from 4177 to 5548 feet. Geology Stratigraphy The sediments penetrated by wells in the Paloma held range in age from Recent to Upper Miocene. The entire section, which exceeds 10,000 ft. in thickness, conforms generally to the standard section of the south central San Joaquin Valley. The producing zone, sometimes called the Paloma sand, is the approximate equivalent of the Stevens sand zone of the Ten Section, Canal, Coles Levee and other fields. The stratigraphic section is shown in Table I. Paloma Producing Zone* (Stevens Sand Zone, Upper Miocene) .-The Paloma producing zone (Fig. 2), frequently referred to as the Paloma sand, is encountered at depths ranging from 9950 to 10,300 ft. In general, it is a massive, firm to hard, not too well sorted, fine to medium fine sand. It is interbedded with thin, hard, calcareous sand shells of similar texture and cherty

Jan 1, 1942

By James T. Wood

Stratigraphy, structure and closure of the Paloma field are discussed, with some details regarding the present state of development. The Paloma anticline, a large dome modified by faults, is the largest single closed dome in the southern San Joaquin valley without surface outcrop or topographic expression. It owes its discovery to geophysics. Of nine wells drilled to the Stevens sand, seven are productive. The ultimate productive area may approximate 3000 acres when the limits of the field are determined. Introduction The Paloma field derives its name from the Paloma school, ½ mile north of what is now the center of the field. The field is 17 miles southwest of Bakers-field, in the south central part of the San Joaquin Valley (Fig. I). The present developed area and its expected extensions are in townships 31 and 32S., R.26E. It is the most southerly of several fields that produce from the Stevens sand zone. The first well to produce condensate was a joint test drilled by the Western Gulf Oil Co. and The Texas Co. near the center of sec. 3, T.32S., R.26E., well No. 54-3. This well was completed on Aug. 31, 1939, at a depth of 10,178 ft. The initial production was 2280 bbl. a day of condensate and 14,750,000 cu. ft. of gas (½-hr. gauge) through a ?-in. bean. Prior to the drilling of this well, the Ohio Oil Co. discovered and developed a small gas field, which embraces a part of three townships about their common corner but lies chiefly in secs. 31 and 32, T.31S., R.26E. The first well was completed on July I, 1934, at a plugged depth of 5239 ft. after having been drilled to 7957 ft, production was found in a 59-ft. zone IIO ft. below the Fourth Mya bed, within the Sari Joaquin clays. Until recently this field was known as the Buena Vista gas field. It is now carried by the Division of Oil and Gas as the Paloma gas field. Production within the Paloma gas field is derived from six wells, producing from several different zones in the interval from 4177 to 5548 feet. Geology Stratigraphy The sediments penetrated by wells in the Paloma held range in age from Recent to Upper Miocene. The entire section, which exceeds 10,000 ft. in thickness, conforms generally to the standard section of the south central San Joaquin Valley. The producing zone, sometimes called the Paloma sand, is the approximate equivalent of the Stevens sand zone of the Ten Section, Canal, Coles Levee and other fields. The stratigraphic section is shown in Table I. Paloma Producing Zone* (Stevens Sand Zone, Upper Miocene) .-The Paloma producing zone (Fig. 2), frequently referred to as the Paloma sand, is encountered at depths ranging from 9950 to 10,300 ft. In general, it is a massive, firm to hard, not too well sorted, fine to medium fine sand. It is interbedded with thin, hard, calcareous sand shells of similar texture and cherty

Jan 1, 1942

By J. Mizrahi, A. M. Baniel, A. Mitzmager, S. Star

This article gives an account of the latest developments in the use of TBE for sink-float separation of silicate minerals. A number of minerals for which the process has been tested and found suitable are reviewed. Specific examples are discussed in relation to the particular problems of sink-float separation and recovery of TBE as compared with non-silicate minerals. The economic aspects are outlined. Silica and silicates comprise the most common and abundant group of minerals, and since they are present in variable amounts in most ores, they constitute an appropriate subject for the review and discussion of the recent developments in the use of TBE for mineral concentration. The silicates considered as a group have an extremely wide range of chemical and physical properties. Some of these properties, which are common to all minerals, are of importance to concentration by TBE and are discussed in some detail in this paper, as well as the development of methods and apparatus for concentration and recovery of TBE and several examples of concentration of silicates. PROPERTIES OF MINERALS WITH RESPECT TO CONCENTRATION BY TBE The properties considered as most important to concentration by TBE are specific gravity, structure, surface and shape. The specific gravity of a mineral is a fundamental property and is constant between very close limits for the same species of different sources if particles are pure and free from cavities or cracks. In many species, however, solid inclusions and changes in chemical composition due to replacement of elements cause variations in the specific gravity. The plagio-clase series of feldspars between albite and anorthite illustrate this point (specific gravity from 2.60 to 2.77). Fig. 1 shows the specific gravity distribution of some of the common silicate minerals.' The highest specific gravity is about 4.7 (zircon) and the lowest is 2.0 (sepiolite), with most of them ranging between 2.6 and 3.5. Although most of the silicates given in Fig. 1 are found as constituents of rocks, those generally considered as rock making minerals are comparatively few. They include quartz, feldspars, nephelite, sodalite, leucite, mica, pyroxenes, amphiboles, chrysolite, kaolin, talc and serpentine. These minerals may appear in igneous rocks as coarse crystals in granites, syenites and diorites or as very fine grained dispersions in basalt and felsite. When the latter rocks occur in an ore, their specific gravities depend on the minerals present and structure. The same is true for the sedimentary and metamorphic rocks (sandstones, shales, gneiss, slate, schists). A comparison of specific gravities for the minerals listed in Fig. 1 with that of TBE (see Table I) shows that the important rock-forming minerals, with the exception of pyroxenes, amphiboles and chrysolite (olivine), lie in the specific gravity range of less than 2.96 and can therefore be separated by TBE. The ore structure is important both in determining the apparent specific gravity and the efficiency of TBE recovery. The structure can be compact (as in

Jan 1, 1963