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By R. G. O’Meara, S. M. Runke

THE Bureau of Mines has been charged by Congress to investigate processes for the production of alumina from low-grade bauxite, alunite, and clay. As one part of the program, an investigation of the application of ore-dressing methods to improve the grade of high-silica bauxite is in progress at the Mississippi Valley Experiment Station at Rolla, Mo. This paper summarizes data obtained so far and presents detailed results of tests on four typical samples. MINERALOGY OF BAUXITE The name bauxite originally was used to designate the dihydrous aluminum oxide (A1203.2H20). The designation has been retained, although the existence of a specific mineral of such composition has been disproved. The term is now applied to ores of aluminum consisting of various mixtures of the minerals gibbsite (A1203.3H20), diaspore (A1203.H20), and boehmite (A1203.H20). The predominant hydrous aluminum oxide in most American bauxite, however, is gibbsite. In some instances bauxite may be amorphous mixtures of the hydrous aluminum oxides that approximate the composition of dihydrous aluminum oxide (A1203.2H20). The proposed name for this material is cliachite. Gibbsite and boehmite, the trihydrate and monohydrate, are soluble in a solution of sodium hydroxide at elevated temperature and pressure, whereas diaspore is practically insoluble. The solubility of these two minerals is the basis of the Bayer process of alumina extraction. All bauxites contain certain impurities, the commonest of which, in the order of their importance, are: silica, principally as a constituent of kaolinite, and to a lesser extent as quartz; iron, as hematite, limonite, and siderite; and titanium, as ilmenite, rutile and leucoxene. Minor impurities are zircon, cobalt and nickel. Bauxite is produced commercially in Arkansas, Alabama, Mississippi, Georgia and Tennessee, but the most important deposits in the United States are in Arkansas, in the vicinity of Little Rock. HISTORY OF BAUXITE BENEFICIATION The literature on bauxite beneficiation is limited, but the reports of Gandrud and DeVaney1 and Clemmer, Clemmons, and Stacy2 show the possibilities of flotation as a means of beneficiating bauxite. Their work has also developed reagent

Jan 1, 1944

By William C. Cooley

INTRODUCTION Considerable research has been conducted on the use of steady and pulsed jets of water at high pressures to produce slots or holes in rock, and to fracture rock. The primary objectives of prior research have generally been to determine the feasibility of excavating or drilling rock or minerals and to determine the optimum jet parameters for this purpose. The present study was undertaken in order to identify the pertinent dimensionless parameters involving jet and rock properties which characterize the liquid jet penetration process and to develop empirical correlations of the existing test data which would permit engineering prediction by means of scaling relationships. The present paper is in the nature of a progress report, because not all the existing test data have been processed. Also effort has been concentrated on correlation of data on the specific energy (jet kinetic energy per unit volume of rock removed or broken), rather than correlation of jet penetration depth, hole diameter, kerf depth or kerf width. However, it is clear that this method of correlating data on specific energy in terms of dimensionless parameters shows great promise and provides insight into the nature of the physical processes of jet erosion and fracture. It therefore can help to avoid drawing incorrect conclusions from limited experimental data. DIMENSIONAL ANALYSIS The method of dimensional analysis is particularly valuable where the mathematical relationships controlling a physical process are unknown or complex. The grouping

Jan 1, 1971

By E. Maltby Shipp

WALLACE MCKEEHAN, Douglas, Ariz. (communication to the Secretary*).-In going over this report, which I have done very carefully, I find that the summary as composed deals with the various problems almost entirely from the employer's standpoint and that practically no consideration is given to the employee's point of view. An experience of 3 ½ years as safety inspector, and almost 30 years as workman-and official, has convinced me that any plan for the betterment of working conditions which will achieve any degree of success must give the workmen their share of responsibility and allow them full participation. The company may finance and direct the movement, but its ultimate success depends upon the support given by the workmen. The cooperation of the men doing the actual work is so essential that all writers insist that this must he secured, but they do not agree as to how this can best be done.

Jan 3, 1917

By R. C. Canby

The American water-jacket furnace is the outgrowth of lead-smelting at Eureka, Nev., subsequently developed in Utah and Colorado. Early smelting in Virginia, New England, or the Missouri-Kansas-Illinois district seems to have had no direct influence in the development of this furnace. First Decade, 1870 to 1880. In 1870, the draft-furnace was used in Nevada, coincidentally with the first crude sandstone blast furnaces, which were 2 or 3 ft. sq., with Sturtevant fans or small Roots blowers, and sheet-iron or water-cooled tuyeres. Stetefeldt, Liebenau, Albert Arents, and 0. H. Hahn mere the early metallurgical leaders. Arents's siphon-tap and the re-establishment of the furnace-bosh mere the most important improvements of the decade. Second Decade, 1880 to 1890. At first there were ,many small local plants; but by the time Eureka had reached its maximum production of lead-ore, two custom works (the Eureka and the Richmond) were treating all the ore, the miners having learned the economy of smelting at larger and well-constructed plants. In the early eighties, most of the features of modern practice were already discernible at Salt Lake, Leadville, Denver, and Pueblo. The small square sandstone furnaces had been replaced by rectangular water-jacket furnaces, mostly 36 in. wide, and from 60 to 80 in. long at the tuyeres, which entered between cast-iron water-jackets. Subsequently, Franz Casin, at the Holden works, Denver, put the tuyeres in the middle of the jackets, and many other improvements were made by him and others, so that the cast-iron jacket became the favorite, until the possibility of

Jan 1, 1913

By Reinhard H. Wöhlbier, George E. Aiken

8.4-1. Introduction. Surface excavating is done on a continuous basis with a variety of machines: 1) trenchers and ditchers, 2) conveyor loaders, and 3) bucket-chain and bucket-wheel excavators (BWE). Surface mining is largely concerned with only the last two machines, although some of the conveyor-loader types are often used by contractors for large-scale earth moving, and the engineer should be aware of these applications. This chapter is restricted to discussing only the bucket-chain and bucket-wheel excavators, with special emphasis on the latter. Continuous digging with these machines is done with evenly spaced buckets on either an endless chain or on the periphery of a rotating wheel. The bucket-chain digger excavates and takes the material away from the face with the same machinery. In the case of the bucket-wheel machine, these two functions are separate. Material is excavated by the buckets and then flows in a continuous stream via a transfer to the conveyor system, which in turn transports it to the discharge point. The wheels are adjustable in rpm and mount 6 to 12 buckets of equal size. These are classed as celled, cell-less or semicelled. The digging ladders for both types can move simultaneously in the horizontal and vertical planes. Ladder control is similar to the operation of a bucket-line dredge. Some ladder-chain and all wheel excavators have the machinery deck and superstructure mounted on a 360° swing circle. Other chain diggers have a fixed machinery deck. Deep and/or high cutting models are available in either the chain or wheel excavator. Machines can be either rail or crawler mounted, but the trend is to crawlers. Many of the early ladder-chain, rail-mounted excavators have been converted to crawlers. These may be either of the single or bogie type, depending on the conditions. Large machines usually use the superior three-point crawler suspension.

Jan 1, 1968

By R. Lyndon Arscott, P. Hackett

This chapter reviews the early stages of a study designed to investigate the physical behavior of the coal measure rocks around longwall panels over a relatively large area. The aim of the work is to attempt to explain a directional tendency for a certain type of underground fracture. The geological structure of the area is reasonably uniform but the effect of some local anomalies is also discussed. Although some definite tendencies have been recorded, the results so far achieved need confirmation by further experiments. The chapter deals first with some in-situ strain measurements carried out in longwall panels and continues with a discussion of the relationships between induced fractures and the natural variations in the structure of the rock mass. Finally, some light is shed upon the gas outburst phenomenon although eradication of the hazard is far from assured. STRESS AROUND A LONGWALL PANEL Considerable progress has been made during the last few years towards the determination of the mechanism of failure of small samples of rock under varying environmental conditions. Much more laboratory testing needs to be done in this field but an even greater amount of study needs to be devoted to the extrapolation of laboratory phenomena to failure around underground excavations. The problem is made more difficult because the stress redistribution around an excavation is often difficult to define, particularly when part of the rock mass fails and a

Jan 1, 1972

By Shiou-Chuan Sun, R. E. Zimmerman

An evaluation of the mechanism surrounding the froth flotation of coarse coal and mineral particles as a result of experiments conducted at The Pennsylvania State College. Maximum size ranges for both bituminous and anthracite coals were established as well as the factors affecting the floating of coarse particles. CONSIDERABLE interest is developing in the froth flotation of coal and the maximum particle sizes which can be treated by such method. The economic necessity of recovering extreme coal fines and slurries plus the restrictions being placed upon stream pollution have brought about many new and prospective installations of flotation plants. Most coal slurries or silts have a wide size range, some sizes of which may be unsuitable for effective froth flotation. This fact also enters into the froth flotation of other minerals and the principles that SHIOU-CHUAN SUN and R. E. ZIMMERMAN, Members AIME, are Assistant Professor and Division Chief, respectively, Division of Mineral Preparation, The Pennsylvania State College, State College, Pa. Joint AIME-ASME Fuels Conference, French Lick, October 1949. TP 2843 F. Disccussion (2 copies) may be sent to Transactions AIME before June 30, 1950. Manuscript received Sept. 12, 1949. apply to coal would also apply to minerals in general. A series of experiments were made by the authors for the purpose of investigating factors influencing the froth flotation of coarse mineral particles and an attempt has been made to evaluate those factors. This paper presents the results of a study of the froth flotation of coal particles in the size range greater than 35 mesh. During the study a "multi-bubble" hypothesis has been developed to explain the various phenomena observed in the behavior of coarse particles in froth flotation of coal. The terms coarse, intermediate, and fine particles as used in this paper are arbitrary and differ for various minerals. For coal alone the term intermediate particles means that the particle size is within the range of 35 and 200 mesh of Tyler sieve sizes. Sizes of coal particles coarser and finer than this size range are termed respectively as coarse and fine particles. Methods of Conducting Flotation Experiments: All of the flotation tests, except those shown in table 1, were carried out in a laboratory Fagergren flotation machine, using 300-a samples of solids for each test. All mineral samples we; prepared from selected lumps of high purity by crushing, grinding, and screening to the desired sizes. Except coals, all the other samples were cleaned through magnetic

Jan 1, 1951

By R. E. Zimmerman, Shiou-Chuan Sun

An evaluation of the mechanism surrounding the froth flotation of coarse coal and mineral particles as a result of experiments conducted at The Pennsylvania State College. Maximum size ranges for both bituminous and anthracite coals were established as well as the factors affecting the floating of coarse particles. CONSIDERABLE interest is developing in the froth flotation of coal and the maximum particle sizes which can be treated by such method. The economic necessity of recovering extreme coal fines and slurries plus the restrictions being placed upon stream pollution have brought about many new and prospective installations of flotation plants. Most coal slurries or silts have a wide size range, some sizes of which may be unsuitable for effective froth flotation. This fact also enters into the froth flotation of other minerals and the principles that SHIOU-CHUAN SUN and R. E. ZIMMERMAN, Members AIME, are Assistant Professor and Division Chief, respectively, Division of Mineral Preparation, The Pennsylvania State College, State College, Pa. Joint AIME-ASME Fuels Conference, French Lick, October 1949. TP 2843 F. Disccussion (2 copies) may be sent to Transactions AIME before June 30, 1950. Manuscript received Sept. 12, 1949. apply to coal would also apply to minerals in general. A series of experiments were made by the authors for the purpose of investigating factors influencing the froth flotation of coarse mineral particles and an attempt has been made to evaluate those factors. This paper presents the results of a study of the froth flotation of coal particles in the size range greater than 35 mesh. During the study a "multi-bubble" hypothesis has been developed to explain the various phenomena observed in the behavior of coarse particles in froth flotation of coal. The terms coarse, intermediate, and fine particles as used in this paper are arbitrary and differ for various minerals. For coal alone the term intermediate particles means that the particle size is within the range of 35 and 200 mesh of Tyler sieve sizes. Sizes of coal particles coarser and finer than this size range are termed respectively as coarse and fine particles. Methods of Conducting Flotation Experiments: All of the flotation tests, except those shown in table 1, were carried out in a laboratory Fagergren flotation machine, using 300-a samples of solids for each test. All mineral samples we; prepared from selected lumps of high purity by crushing, grinding, and screening to the desired sizes. Except coals, all the other samples were cleaned through magnetic

Jan 1, 1951

By Charles M. Haas

WHEN minable ore has been located, the problem of mining is synonymous with the problem of movement --movement of men and equipment to mine the ore, and movement of the ore from the earth to the mills. In slusher drifts and shafts, on shovels and dragline excavators, on churn drills and bulldozers, wire rope is essential to the transportation of men, ore, overburden, and equipment. Although a casual glance creates the impression that all wire ropes are alike, there are crucial differences between ropes. Strand diameter, number of strands, weave, core, and resistance to corrosion all decide the type of job a wire rope can do, and where and how long it can do that job. These factors are, of course, the responsibility of the rope manufacturer. Beyond this, he can extend his function into the mine itself by advising users on the use, care, and maintenance of these sinews of the mining industry. This article, then, covers both the manufacturing and end-use aspects of wire ropes.

Jan 9, 1951

By D. I. Bardos

The occurrence of Laves phases (AB,) in various binary alloy systems has been reviewed in recent papers.13 Iron forms Laves phases with Sc-, Ti-, V- and Cr-group elements. However, two of the corresponding Laves phases with cobalt, namely MoCo, and WCo,, are missing. Nickel forms binary Laves phases with Sc and Y, but not with any Ti-, V-, or Cr-group element. These conditions are schematically illustrated in Table I. That electron concentration is a significant factor in determining which type of Laves phase is formed in a given case was recognized long ago by Laves and Witte,4 This concept has been more recently applied to Laves phases formed by transition ele-ments. It now appears that the average electron concentration (average number of electrons per atom outside of the closed shells of the component atoms) may be an important factor also in determining whether or not a Laves phase can occur at all in a given system. As shown in Table I, in the transition element systems considered Laves phases are absent at electron concentrations of 8, or larger (to the right and below the double line in Table I). These absences clearly cannot be accounted for on atomic size considerations, as evidenced by the many inconsistencies apparent in Table 11. While the ideal radius ratio for Laves phases is 1.222, in the systems which do have Laves phases the ratios of CN 12 radii range from 1.10 to 1.46. The consistent absence of Laves phases at RA/RB< 1.10 might be attributed to the low values of these radius ratios. However, Table II shows that absences also occur irregularly throughout the radius ratio range covered. In a previous paper7 it was concluded that, in transition element systems forming u-phases, silicon may act as an acceptor of electrons, thus stabilizing the u-phase at electron concentrations higher than

Jan 1, 1962

By E. C. Bain

THE more familiar compositions of iron-carbon-chromium1 and the iron-carbon-tungsten2 systems have been investigated with a degree of thoroughness which has permitted the construction of their three-dimensional equilibrium diagrams; and it is probable that these equilibrium diagrams are sufficiently accurate for the present metallographic needs. Strangely enough, in spite of their importance, the alloys of iron, carbon and manganese apparently have not been investigated in the same systematic manner, and so far as is known, no three-component equilibrium diagram for this system is available. Even iron-carbon-nickel alloys3 have been studied rather more thoroughly; for these the solidus and liquidus surfaces have already been determined, but the solid transformations in this, as in the manganese system, have not been reported systematically. The present paper deals with the constitution at equilibrium of a series of 36 iron-carbon-manganese alloys of commercial purity limited by 1.5 per cent carbon and 15 per cent manganese, a range of compositions including most of the manganese steels. The temperature range of melting has not been determined, nor has the high-temperature (delta iron) ferrite equilibrium been included in the study, it being considered that the more important characteristics of the manganese steels are their ordinary transformations in the solid state. The delta iron region is almost certain to be a small tetrahedron not very different in magnitude or contour from that in the iron-carbon-nickel diagram. It is probably true

Jan 1, 1932

Sulfuric Acid and Phosphate Industries at Anaconda Reduction Works. BY E L LARISON (Contribution 70-Preprint 4400 words) In 1915 a 135-ton chamber sulfuric acid plant was built at the Anaconda Reduction Works to supply acid for leaching sand tailing Sulfur dioxide was obtained by roasting copper table concentrate Soon after, the flotation process, using acid as a reagent, together with development of a leaching and electrolytic process for zinc recovery, necessitated building a second acid unit of 50 tons&apos; per day capacity, completed in 1917 Within a few months the zinc process was so improved as to consume no added acid Mean¬while research work was in progress on production of phosphate fertilizers using sulfuric acid and Idaho phosphate rock In 1920 a pilot plant was put into operation which treated 50 tons per day of phosphate rock to produce treble superphosphate containing 45 per cent available P205 In 1922 the original plant and process for leaching of sand tailing were abandoned in favor of a combination leaching and flota¬tion process In 1923 the sand leaching plant was remodeled into a treble super¬phosphate plant designed to treat 160 tons per day of phosphate rock. In 1924 the copper flotation process was put on alkaline circuit and acid, has not since been used as a reagent Practically all the acid produced is now used for making phos¬phate products In 1931 the use of copper concentrate as a source of sulfur dioxide was abandoned and an iron concentrate, floated from the copper concentrator tail¬ing, substituted

Jan 1, 1935

By Lester Woolsey

THE State Department can be of assistance to Americans in the petroleum business directly and indirectly. During the past few months, at the Arms Conference, it had a large hand in dealing with affairs indirectly affecting the oil problem. The conference has somewhat relieved the emphasis on naval strategy in relation to oil supply by limiting the number of naval vessels or the fleets of the Great Powers and in maintaining the "open door" in the Far East in respect of the development of the natural resources of that region by defining that policy in a nine-power treaty. The largest competitors of the. United States in the petroleum field are parties to that treaty. The Department of State also has stood steadfastly for the principle of equal opportunity in the Dutch East Indies, Mesopotamia, and Persia. The Department of State has been of indirect assistance in connection with oil problems by insisting on the recognition of treaty rights and other guar-antees, such as most-favored-nation clauses, and mandate provisions. I am not speaking as a representative of the Depart-ment of State, as L now have no connection with that institution, but my experience of several years as a member of the department and my practice since my resignation have given me opportunity to see the department from both the inside and the outside, and to measure its limitations as well as its resources.

Jan 7, 1922

By James Norman

SPODUMENE is a lithium-bearing pyroxene, and is an important source of lithium compounds. Because of its high alumina and lithia content it might be a desirable constituent of glass batches. The use of spodu-mene in ceramics will undoubtedly increase, as it has been shown that a mixture of the proper proportions of this mineral with soda feldspar and potash feldspar has a much lower maturing temperature upon firing than has any one of the three components.1 The mineral spodumene seldom occurs as pure mineral, but ordinarily with feldspars, mica and quartz. All spodumene-bearing rocks tested contained these minerals as gangue. Small amounts of iron and manga-nese oxides also were present, usually as stains on the silicate grains. Mica associated with the spodumene carried a considerable amount of lithia. This was discovered in flotation tailings, which, although virtually free of spodumene grains when examined microscopically, showed 0.4 to 0.5 per cent Li20 on chemical analysis. The lithia content of micas picked from the North Carolina spodumene rock was variable. Some samples contained little lithia, others more than 3 per cent. In 1938, under the supervision of Oliver C. Ralston, ? the Bureau of Mines, in cooperation with the Tennessee Mineral Products Corporation, undertook to study the beneficiation of North Carolina spodumene by froth flotation. The Bureau had previously published investigations on the beneficiation of spodumene.2,3 The methods described in the second publication&apos; did not give good results with badly weathered spodumene rock, so that more thorough investigation of the subject was warranted.

Jan 1, 1940

By Benjamin LeRoy Miller, Joseph T. Singewald

The ore deposits at Firmeza have been worked continuously since 1884; those at Daiquiri since 1895. It is surprising, therefore, that they have not been the object of careful geologic study until quite recently. It is true that considerable attention was paid to these deposits by A. C. Spencer, in 1901, in the report on the geology of Cuba, by Hayes, Vaughan, and Spencer,l but this was only incidental to a hasty general reconnaissance of the Island. As far as the Daiquiri deposits are concerned, this gap has been filled by the appearance of the two papers by Prof. James F. Kemp2 and by Prof. Waldemar Lind-gren and Clyde P. Ross respectively.3 Max Roesler, first holder of the Emmons fellowship, made a detailed study of the Firmeza deposits during the past summer, so that soon we can expect a full description of them. Consequently, there is no, demand at the present time for a description of the deposits from other sources, and that is not the purpose of this paper. The papers on Daiquiri, however, leave unsolved problems in regard to the age of the rocks of the district and certain phases of the genesis of the deposits, and it is with the hope of aiding in the solution of some of these problems that this contribution is offered. Kemp, and Lindgren and Ross agree in assigning these deposits to the type of contact metamorphic deposits. They disagree in part on the question of their localization. The deposits occur in an extensive area of diorite which includes numerous blocks of limestone, and sometimes are found in the contact zones between these blocks and the diorite, and in other instances are completely enveloped in the diorite, showing no apparent connection with the limestone. The latter class includes

Jan 1, 1916

By J. M. W. Mackenzie, M. H. Buckenam

Flotation experiments using stearic, oleic, linoleic, linolenic, and ricinoleic acids and naturally occuring products rich in these acids as collectors for calcite are described. The results confirm the validity of the rule of Hukki and Vartiainen relating the collecting power and unsaturation of the C18 acids. Reasons for this relationship are discussed and a close relationship between mineral depression and critical micelle concentration is reported. It has long been recognized that the unsaturated fatty acids are in general superior flotation collectors to their saturated homologues. Whereas earlier workers concentrated on saturated and monoethe-noid acids, recent investigations have centered on oleic, linoleic, linolenic, and the substituted mono-ethenoid acid: ricinoleic. From studies of the collecting properties of palmitic, oleic, linoleic, and linolenic acids on ilmenite, rutile, hematite, and magnetite, Hukki and Vartiai-nenl concluded that the collecting power of fatty acids increased with unsaturation of the hydrocarbon chain. Sun, Snow, and Purcel12 investigated the collecting properties of unsaturated fatty acids as collectors for phosphate ores and concluded that the collecting power increased with increasing unsaturation of the hydrocarbon chain up to two double bonds and that further unsaturation decreased the collecting power. More recently Sun3 studied the collecting power of the C18 fatty acids stearic, oleic, linoleic, and linolenic on 37 minerals. The results of these experiments with a few exceptions showed that the collecting power of the acids increased in the order stearic, oleic, linoleic, and linolenic. The relative collecting powers of linoleic and linolenic acids were in many cases altered by the cleanliness of the mineral surface prior to flotation. Sun concluded that linolenic acid may become oxidized by atmospheric oxygen during flotation, a reaction which would reduce its effectiveness as a collector. This deduction is supported by Gaudin and Cole4 who concluded that oleic and linoleic acids do not undergo appreciable oxidation of the double bonds during flotation but that the linolenic acid double bonds are measurably affected. The most complete investigation on the influence of hydrocarbon chain unsaturation on the collecting properties of fatty acids is that of Kivalo and Lehm~svaara.~ These workers using linolenic acid of a higher purity than Hukki and Vartiainen showed that this acid was superior to oleic and linoleic acids as a collector for magnetite. They also found that ricinoleic acid was a more effective collector for this mineral than the other acids investigated, an observation particularly apparent at high collector concentrations. Seeking to explain the superiority of the unsaturated acids these authors considered the effects of critical micelle concentration, surface activity, hydrolysis, and cross sectional area of the hydrocarbon chain in relation to unsaturation. Using what, according to the results of Caviere are erroneous surface tensions of the soap solutions of these acids, they concluded that the surface activity decreases and the critical micelle concentration increases with increasing unsaturation. In view of the data of Cavier, whose results show that surface activity of these soaps increases with unsaturation, the deductions of Kivalo and Lehmusvaara are open to criticism. The degree of hydrolysis of the soap solutions as measured by Kivalo and Lehmusvaara decreases as the unsaturation of the fatty acid increases, a result which helps to explain the superiority of unsaturated acids as collectors. In view of the superiority of unsaturated acids as collectors for many minerals, attention has been directed towards the utilization of fatty acid raw materials such as tall oils and linseed oils which contain considerable quantities of these acids. This paper describes test work to determine the effect of unsaturation of the hydrocarbon chain on the collecting properties of fatty acids on calcite, and includes comparable test work using natural products rich in unsaturated acids. TEST WORK Reagents: The pure fatty acids used were oleic, linoleic, and linolenic. Of these, oleic was supplied by British Drug Houses Ltd. and the others were produced by the Hormel Inst. When not in use these

Jan 1, 1961

By AIME

A NATIVE son of Salt Lake City. David Douglas Moffat has contributed greatly to both the mineral industries and civic progress in the State of Utah. He was born in 1880 and his whole life bas been intimately associated with mining and milling. His father, one of Utah&apos;s pioneer mining men, was superintendent of a mill at Park City. When Moffat was only 18 years of age he went to Philipsburg Mont., where he spent several years as a machinist, and later as master mechanic for the Granite Bi-Metallic Mining Co. He returned to Park City in 1903 as master mechanic and night mill foreman for the Ontario Silver Mining Co. After a few years of varied experience he became, in 1910. general foreman of the Boston Consolidated Will at Garfield, Utah.

Jan 1, 1947

By T. W. Smoot

Bentonites are composed chiefly of montmorillonites which are clay minerals generally distinguished from other clay minerals by their surface activity and extremely fine particle sizes. The uses of bentonite are many and varied, depending principally on one or more of the following characteristics: 1) Thixotropy, 2) Dispersion, 3) Plasticity, 4) Swelling, 5) Surface area, activity, ab- and adsorbtive properties. Some of the major uses of bentonite are briefly reviewed as are the mineralogical and physical properties. The uses of X-ray diffraction, differential thermal analysis and other tests for physical properties are reviewed as to their uses in evaluation. In the past 40 years, the industrial uses of bentonite have grown to include many applications. The physical and chemical properties of bentonites are such that they can be used as catalysts, adsorbants, plasticizers, binders, drilling muds, and pelletizers. Not all bentonites, however, can be used for all of these purposes and some are probably of little or no value for any use. The purpose of this paper is to briefly review the mineralogical, physical, and chemical characteristics and variations of bentonites. The determination of these characteristics and their uses in industry are also reviewed so that these determinations can be used as guides for evaluation. DEFINITION OF BENTONITE The word bentonite, as used in this paper, refers to a clay material, usually (but not necessarily) the result of the in-place-weathering of volcanic ash. Its mineralogical composition is dominated by the clay mineral montmorillonite and generally carries other clay minerals and silica minerals as the major &apos;impurities&apos;. For this discussion, such a definition is justified since most of the economic uses of bentonite~ depend upon the physical and chemical characteristics of the montmorillonite minerals involved. The terms montmorillonite and bentonite have been used almost interchangeably in industry although the latter is much more commonly used. Therefore, where montmorillonite is discussed, it should be understood that the major feature of a bentonite is the subject. STRUCTIJRE OF MONTMORILLONlTE The economic importance of bentonites is generally based on one or more of the following characteristics of montmorillonite: 1) high-thixotropy and easy dispersion in water, 2) high-plasticity, 3) swelling properties, 4) large surface area/unit mass, 5) high surface activity, and 6) adsorptive properties. To understand these properties, an appreciation of the structural scheme of montmorillonite is helpful. Montmorillonite IS one of the three-layer clay minerals composed essentially of hydrous aluminum silicates. The essential building blocks of these layered silicate:; are: 1) silica tetrahedron composed of a silicon atom surrounded by four oxygen atoms, and 2) aluminun (iron, magnesium, etc.) octahedral unit that, ideally, has one of these atoms surrounded by six hydroxal units. Fig. 1 is a diagrammatic sketch of the montmorillonite structure. In the montmorillonite structure, the tetrahedron are pointed inward and attached to the octahedral units so that the O= atoms replace the hydroxal units where they are bonded; hence two-thirds of the hydroxal units

Jan 1, 1962

By Frederick J. Rich

INTRODUCTION Coal characterization involves a variety of analyses which are designed to yield as much information as possible about the properties of coal. The types of analyses which are now regarded as necessary for any truly quantitative assessment of coal include the following: 1. proximate analysis 2. ultimate analysis 3. petrographic analysis The two traditional forms of analyses are the proximate and ultimate types. A proximate determination reveals the amount of moisture, volatile matter, fixed carbon, and ash which are present in the coal. Nowadays, a sulfur determination is usually included in the proximate analysis. The ultimate analysis, in contrast, includes a major alkaline oxide determination, which tells how much sodium, calcium, and potassium are found in a sample. Sulfur forms, i.e. sulfide and sulfate vs organic sulfur, are also identified as well as carbon, hydrogen, oxygen, nitrogen, and trace element concentrations. Proximate and ultimate analyses have been used for many years. The petrographic analysis, one which identifies and quantifies organic microcomponents of coal, is a comparatively new technique of coal characterization. Petrography adds great detail to a coal analysis and, to be sure, is a necessary component of any complete analysis. Coal is not at all uniform in its composition. Material from different mines within one coal-producing region will display varia-

Jan 1, 1983

By J. J. Bikerman

In a recent study&apos; of the martensitic transformation of Cu-Zn ß-phase alloys, it was noted that the MS temperature at the surface was raised due to the loss of zinc by volatilization. It seems likely, therefore, that the MS temperature may serve as a guide for the measurement of composition. From a knowledge of the dependence of the transformation temperature on composition, 2 it should be possible to detect variations in zinc content which are less than 0.1 at. pct by measuring the MS temperature throughout the sample. It is unlikely that an electron microprobe analysis could detect accurately such small zinc losses because the presently accepted limits of accuracy of the micro-probe analysis in simple ternary systems are of the order of 2 to 5 pct of the amount present.3 In the present study, a composition gradient was produced by precipitating the a primary solid solution, and reheating for a very short time within the 0-phase field. The nominal composition, in atomic percent, of the ternary ß-phase alloy used, 64.2 Cu, 34 Zn, 1.8 Si, was selected because it had an MS temperature of +4°C, thereby simplifying the experi-

Jan 1, 1968