Search Documents

By Etienne A. Ritter

The Evergreen mine, located at Apex, in the northern part of Gilpin county, Colorado, has opened a very peculiar and interesting copper-deposit, in which both bornite and chalcopyrite occur as rock-minerals. The country-rocks are crystalline schists cut by dikes of granu-lite and of pegmatite. At the Evergreen property they have been cut by a dike of a uew kind of eruptive rock, to which I have given the name " Evergreenite." The rock is composed of quartz, alkali feldspars, orthoclase and albite (often interlocked as microperthite), with augite of the ægirine variety and long needles of enstatite and diallage. For reasons stated below, I believe the dike to be of Tertiary age. It is easily traced on the surface of the ground, from a point in the bottom of Pine creek, about a mile below Apex, to the top of Nevada hill, 1,500 ft. beyond and 600 ft. above it. (See Fig. 1.) It varies from 3 to 12 ft. in width, and is bounded on both sides by contact-zones about 60 ft. wide, in which the crystalline schists have been changed into pseudo-quartzites or pseudo-gneisees, according to the injection of an excess of quartz or of feldspars through the special layer of the schists. The most interesting feature is the presence of the pyroxenes, which are always found, though in very variable proportions from place to place, in the layers of these metamorphosed crystalline schists. The dike has torn from its walls a large number of fragments of the wall-rock. It must have been in a viscous state when that happened, because these fragments of the wall-rock do not show any sign of resorption or of assimilation by the magma. In places they are so distinct and so numerous that the rock looks to the naked eye like a pseudo-breccia, of which, never-

Jan 1, 1908

By Milton E. Wadsworth, W. Martin Fassell, William H. Dresher

A study of the rate of dissolution of molybdenite (MoS2) in alkaline solution was carried out under carefully controlled conditions. Effects of temperature, oxygen over-pressure, and KOH concentration were evaluated. Studies were made in the temperature range 100°C to 175°C and in the pressure range 0 to 700 psia of oxygen. Under these conditions molybdenite was found to leach according to a linear mechanism. Both oxygen over-pressure and KOH concentration were found to control the rate of leaching. The mechanism has been explained in terms of adsorption of oxygen at the molybdenite surface followed by configurational rearrangement of the adsorbed molecules. The hydroxyl ion dependency is believed to be diffusion-controlled. Laboratory batch studies have shown that molybdenite can be readily dissolved in alkaline solutions under moderate conditions of temperature and pressure. Commercial application of this process to the production of ferro-molybdenum and molybdenum chemicals is promising in view of the ease of dissolution of molybdenite and the relatively noncorrosive conditions involved in the process. HIGH temperature-high pressure techniques have long been used to great advantage in the organic chemical industry, the petroleum industry, and the paper industry. Only recently, however, have these methods been used to extract metals from their ores on a commercial scale. The Chemical Construction Corp., together with interested producers of nickel and cobalt, has done much to develop methods of producing nickel and cobalt powders by the use of high temperature-high pressure techniques.' The Howe Sound Co. is currently operating a plant near Salt Lake City in which the new Chemical Construction Corp. technique is applied to cobalt-arsenic sulfide concentrates. In this method the concentrates are leached in a dilute solution of sulfuric acid under air pressure at a high temperature. Near Edmonton, in Alberta, Canada, the Sherritt Gordon Co. is also using the new method in conjunction with its ammoniacal leach process.' National Lead Co., at Fredricktown, Mo., is operating a process similar to that of Howe Sound. In spite of the rapid growth of high temperature-high pressure hydrometallurgical processes, there has been very little work done on fundamental principles involved in this type of process. Conse- quently the literature lacks any significant data in this field. Oxidation of pyrite,3 phalerite,4 galena,5 and recently molybdenite" in alkaline solutions has been reported to some extent. This investigation was initiated, therefore, to broaden the application of high temperature-high pressure hydrometallurgy and also to contribute some insight into the basic mechanisms of oxidation in an aqueous medium under these conditions. In addition to the immediate consequences of these processes much valuable information remains to be learned about fundamental reactions when they are carried out at temperatures and pressures slightly higher than those normally encountered. Leaching of molybdenite by alkaline solutions under oxygen pressure has recently been reported in the Russian literature by E. S. Usataya,8 who found that leaching rate increased with an increase in the pH of the solution—the strongest effects being observed at a pH of 10—and also with an increase in temperature. Usataya also has reported the formation of a protective film on the surface of the molybdenite when the leaching solution was weakly alkaline, neutral, or acidic. He believes that this oxidation process explains the migration of Mo+ + in the oxidation zones of molybdenite ore deposits and the subsequent impoverishment of the ores. Equipment: The high temperature-high pressure reaction unit used in this work was especially designed for kinetic studies of this nature, emphasis being placed on accuracy of measurement and precision of control. As details of the unit's construction and operation have been discussed elsewhere,7 Only basic features and principles of operation will be discussed at this point.

Jan 1, 1957

By Dorsey Hager

The possibilities of finding new oil pools in Oklahoma and Kansas are far from promising. In 1916, the only new pools of importance were the Franchot pool near Bixby, the Garber, and the Billings pools in Oklahoma, and the Virgil and Utopia fields in Greenwood County, Kansas. In the first 8 months of 1917, a small pool of unknown extent was opened south of the Stone Bluff pool in Oklahoma, and a pool near Casey, Paunee County, Oklahoma. In Eastern Kansas, interest has been caused by the sinking of new wells near the old Iola pool, but nothing of magnitude has yet been found. The outlook for new pools is far from encouraging, especially as geological surveys have covered all of Oklahoma and Kansas. There are a few areas where geological surveys throw little or no light on the subject, as exposures are poor, but the chances of finding new pools in such areas are slight indeed, if one can judge from the past history of such areas. So far the geologists have based their opinions largely upon the presence or the absence of geologic structure, such as anticlines, domes, and terraces, but some pools will most certainly be found where no surface structure exists, but where local changes in the sand body favor oil accumulations. However, the possibilities of new pools off structure are small, as fully 90 per cent. of the oil pools are on definite structure. In the past, it is estimated that one test in 150 "wild cats" or new tests has brought in a new field. The writer feels safe in asserting that the proportion will decrease still further, so that but one out of 500 new tests may bring in a pay well in a new area. Prom now on the principal field of work in Oklahoma and in Kansas will consist in developing the present pools. The years 1915, 1916 and 1917 saw the high peak of Oklahoma and Kansas oil production. The Eldorado and the Augusta oil fields present the largest possibilities for continued production in Kansas. These two pools have been scarcely more than one-third developed, and have greater potentialities than any of the present Oklahoma pools. In Oklahoma, pools of magnitude should

Jan 1, 1918

By D. W. Gillmore, C. C. Wright

DEWATERING is a major problem in the preparation and utilization of fine-sized coals now being recovered in increasing amounts from colliery effluents, refuse banks, and silt ponds. Of the various methods which have, been proposed for dewatering fine coal, gravity drainage is probably the oldest and most widely used, and yet little information on this subject has been published. Consequently a laboratory investigation of gravity drainage phenomena was undertaken not only to provide basic data for predicting the drainage behavior of fine coals in cars, bunkers, basins, and silos, but also to obtain some understanding of the moisture retention properties of fine coal. Because of practical interest in the problem, a reproducible laboratory technique, which simulated plant conditions as closely as possible, was developed for the evaluation of drainage variables. The ap- paratus selected consisted of vertically-mounted lucite columns, nominally 4 to 8 ft in length and 2, 3 or 6 in. in diam; the bottom of the column was provided with a rubber stopper through which was inserted a -in. diam drainage tube; a wad of glass wool was placed on the upper part of this outlet tube to retain the coal and a plug was temporarily located at the lower end to prevent drainage during charging of the column, see Fig. 1. The most satisfactory testing procedure is as follows: 1—The fine coal, which has been thoroughly

Jan 1, 1953

By D. W. Gillmore, C. C. Wright

DEWATERING is a major problem in the preparation and utilization of fine-sized coals now being recovered in increasing amounts from colliery effluents, refuse banks, and silt ponds. Of the various methods which have, been proposed for dewatering fine coal, gravity drainage is probably the oldest and most widely used, and yet little information on this subject has been published. Consequently a laboratory investigation of gravity drainage phenomena was undertaken not only to provide basic data for predicting the drainage behavior of fine coals in cars, bunkers, basins, and silos, but also to obtain some understanding of the moisture retention properties of fine coal. Because of practical interest in the problem, a reproducible laboratory technique, which simulated plant conditions as closely as possible, was developed for the evaluation of drainage variables. The ap- paratus selected consisted of vertically-mounted lucite columns, nominally 4 to 8 ft in length and 2, 3 or 6 in. in diam; the bottom of the column was provided with a rubber stopper through which was inserted a -in. diam drainage tube; a wad of glass wool was placed on the upper part of this outlet tube to retain the coal and a plug was temporarily located at the lower end to prevent drainage during charging of the column, see Fig. 1. The most satisfactory testing procedure is as follows: 1—The fine coal, which has been thoroughly

Jan 1, 1953

By Abdul-Fattah K. Kaddou, P. C. Rosenthal

THE authors have studied the problem of temper brittleness in steel1 employing an internal friction method. The specimens are in the form of wire, 14 B and S gage (0.064 in diam), 6 in. long. It was very desirable to have an apparatus to test the wire specimens for temper brittleness without making standard notched-bar Izod or Charpy impact tests. Such a device would have two favorable advantages: the first is that no standard impact specimen would be necessary, thus saving time and labor; the second is that there would be a direct correlation with internal friction results, thus eliminating the size factor if standard impact specimens had to be used. A search was made without result to find a commercial apparatus for this purpose. The literature was surveyed to investigate if such a test had been utilized. No such work has been reported in the literature; however, zapffe2 has described an apparatus used for testing for hydrogen embrittlement in

Jan 1, 1961

By Charles W. DeWitt

The ore treated at the reduction plant (called Yangdei) of the Chiksan Mining Co., Korea, is brought from four of the company mines, and from the small tribute mines. The largest shipments come from Sajunkohl mine, situated about a mile and a half from the mill (Fig. 1). The ore is quartz of medium hardness. The average assay value in gold is $6.95 per ton. At the mine the ore is put into bins, and is then trammed over an 8 per cent, grade to the tipple bins above the mill, where the ore is drawn through the mill holes as desired. The capacity of the tipple bins is about 3,500 tons. Ore from Moonsukohl, Chung Tarrie, Yang Chun, and the tribute mines is brought in by bulls and bull wagons. The bulls carry from 350 to 800 lb.; the average wagon load is about 1,200 1b. (Fig. 2). One shovelful of ore out of every ten is taken as a sample. Considerable ore is brought in from the outside mines, and this method of sampling is

Jan 1, 1916

S. F. Emmons, Washington, D. C.: Mr. Malcolmson's paper on the intensely interesting deposits of the Sierra Mojada creates a strong desire to visit the region so well described. Although it is difficult to intelligently discuss a locality that one has never seen, I cannot refrain from offering some remarks in the nature of a tentative suggestion: 1. Age of Beds.—Mr. Malcolmson speaks of the enormous thickness of limestone forming the Sierra Mojada as belonging to the Carboniferous series. If this is not a typographical error, it seems that he should present some evidence for such age, for Chism,* in his previous article on the district, says the only fossils found there were said to be Cretaceous; and it is well known by the investigations of R. T. Hill and others that the great thickness of limestone in this part of Mexico is of Cretaceous age. 2. Structure of Mountains.—Mr. Malcolmson presents good reasons for thinking that the structure of the two related mountain masses (Sierra Mojada and Sierra Planchada) is not the simple anticlinal fold given by Mr. Chism's section, it being evident that there has been faulting as well as flexure. I venture to add that the facts presented by Mr. Malcolmson seem to suggest the possibility that, instead of being simply an eroded anticline, the valley between the two ranges may have been formed, in part at least, by the irregular faulting down of the intermediate block, on the surface of which the volcanic breccia had originally accumulated at a higher level. The sections of the Exploradora and the San Josh mines, in the smooth surface of the contact, with clay selvages and the occasional slickensides, certainly suggest a structural fault between the limestone and breccia. The arrangement of some of the

Jan 1, 1902

By D. J. Wynnemer, G. W. Preckshot

Precise electromotive force measurements have been made on the zinc-cadmium system over the temperature range 700° to 900°C. Activity coefficients, partial free energies, enthalpies, and entropies have been determined .for the entire composition range. The integral heat of mixing is positive and compares favorably with calorimetrically determined values. Vapor-liquid equilibrium compositions were determined .for a total pressure of 1 atm and these agree well with previous values determined in other ways. The use of electromotive force measurements to obtain thermodynamic data for liquid metal systems is a simple and well-known method. Several reviews of the various experimental methods and results have been published.2,3,11 However, most of the past work using this technique was carried out at temperatures slightly above the melting point of the alloy system where alloy composition changes due to vapor transport and increased metal solubility in the electrolyte are not important factors. One advantage of extending the electromotive force measurements up to and including the normal boiling point of the alloy is that it is then possible to evaluate the vapor-liquid equilibrium of the alloy at various pressure levels up to 1 atm. A detailed discussion of the thermodynamics of reversible electromotive force cells can be found in most advanced physical chemistry or chemical thermodynamic textbooks. The expression stating the inter-relation of the electromotive force and the thermodynamic functions is the Gibbs-Helmholtz equation.

Jan 1, 1962

Jan 1, 1902

By Clyde E. Williams

MORE has been said about the iron and steel situation on the Pacific Coast than has been done .about it; but perhaps as much has been done as conditions have warranted. The production of finished steel in an amount sufficient to take care of the local demand for certain sizes and shapes is an established industry on the .coast. The amount .and the variety of products, so made, changes with the demand or them which is largely dependent upon the growth in population. An increasing demand will not always increase the quantity of steel produced locally because the cost of production may rise so -high as to let in steel from the outside. The reason for this is that all of the steel made in the West comes from steel scrap, the supply of which is .limited. From the standpoint of the metallurgist, it would. be desirable to subititute pig iron for some of ' the steel scrap, but this cannot be done profitably because the pig iron now available is too expensive. In other words, the large future demand for steel and pig iron on the Pacific Coast must be supplied by reduction of ores in the West, unless we are to be content with paying high transportation costs for material produced elsewhere. ."

Jan 1, 1924

By L. A. Roe

The flotation of fine particles less than five microns in diameter and the flotation of liquids from liquids generally requires bubble generation methods different than methods used in dispersed air type machines used in mineral flotation. Conditions in the separatory zone in mineral cells are generally more dynamic as compared to the quiescent conditions often absolutely necessary for the flotation of fine particles and liquids. An example of quiescent flotation with very fine bubbles is the lithium flotation plant which operated at Trona, California for 34 years, until it ceased operations in 1978. A review of the process development and the commercial flotation operations at Trona is given in this paper. The clarification of oil field brines by flotation of the oil from the brine has been used for over twenty-five years. Recent installations related to the Prudhoe Bay oil field and the Alaska pipeline are described.

Jan 1, 1980

By J. L. Carne

ORE control is a matter of planning and supervision based on a foreknowledge of the content and distribution of ore. The Inspiration orebody is predominately a copper-sulphide blanket, overlain by an oxidized zone of copper silicates, copper carbonates, and barren capping. Most of the ore is treated by leaching, and the optimum requirement of this method is the goal toward which the mining schedule is aimed. Both open-pit operations and underground mining are used. The problems of ore control at Inspiration are: I—maintenance of metallurgical balance, 2—conservation of oxide ore, and 3—mining out of the orebody at an average grade which parallels that of the reserve figure. Prior to the fall of 1926 all of the Inspiration division ores were treated by flotation, but the mixed ores of the Live Oak—Keystone section carried too large a proportion of copper in the form of chrysocolla for satisfactory flotation. For this type of mixed ore the leaching process now in use had been worked out, and the plant was put into operation in the fall of 1926. The process is known as the ferric sulphate leach, and the leaching solvents contain both ferric sulphate and free sulphuric acid. Sulphide copper in the form of chalcocite is leached by the ferric sulphate, and the oxidized copper minerals are dissolved by the sulphuric acid. From the beginning of operations to the present time the plant has treated some 67 thousand tons of ore having an average copper content of 1.142 pct, of which 0.605 pct has been in the form of oxidized copper minerals. The plant is currently being operated at the rate of 11,500 tons per day, 7 days per week. However, this tonnage is produced in 6 days of mine operation. The average current grade is approximately 1 pct copper, of which about 50 pct is present as oxidized or acid-soluble copper. Close control of metallurgical procedures is a vital factor in operation of the plant and is in turn dependent upon careful regulation of feed. An excess of sulphide copper requires the presence of more ferric sulphate in the leaching solvents. On the other hand, an excess of ferric sulphate in the presence of a low sulphide feed seriously reduces the efficiency of electrolytic precipitation in tank house operations. This condition must be avoided at all costs. An additional factor must be considered. It is known that the sulphide content is predominant in the ore which remains in the reserve. To maintain the necessary sulphide-oxide proportion, so that the entire reserve will mine out at both a grade and a sulphide-oxide ratio that will be permissible throughout the remaining life of the property, it is obvious that the oxide reserve must be currently preserved to as great an extent as possible. Fortunately much of the oxide reserve is found in the open-pit operation. This happy circumstance adds flexibility to the procedure and makes it possible to maintain the close regulation necessary to insure best overall results, both mining and metallurgical. The two ore streams from the pit and underground operations join at the coarse-crushing plant, and proper control must be exercised before the ore reaches this point. The open pit is currently providing about 55 pct of the ore and underground operations the balance of production. Both operations are under a single superintendent so that the closely interrelated problems may be more readily controlled. The least flexible of the two producing units is the underground mine, where the mining method is block caving. Although a block of ground may be undercut and developed, characteristics of the material determine its caving action. The ore in the chutes must be drawn. The area currently mined from underground is in a zone predominately sulphide and is generally

Jan 1, 1953

By J. L. Carne

ORE control is a matter of planning and supervision based on a foreknowledge of the content and distribution of ore. The Inspiration orebody is predominately a copper-sulphide blanket, overlain by an oxidized zone of copper silicates, copper carbonates, and barren capping. Most of the ore is treated by leaching, and the optimum requirement of this method is the goal toward which the mining schedule is aimed. Both open-pit operations and underground mining are used. The problems of ore control at Inspiration are: I—maintenance of metallurgical balance, 2—conservation of oxide ore, and 3—mining out of the orebody at an average grade which parallels that of the reserve figure. Prior to the fall of 1926 all of the Inspiration division ores were treated by flotation, but the mixed ores of the Live Oak—Keystone section carried too large a proportion of copper in the form of chrysocolla for satisfactory flotation. For this type of mixed ore the leaching process now in use had been worked out, and the plant was put into operation in the fall of 1926. The process is known as the ferric sulphate leach, and the leaching solvents contain both ferric sulphate and free sulphuric acid. Sulphide copper in the form of chalcocite is leached by the ferric sulphate, and the oxidized copper minerals are dissolved by the sulphuric acid. From the beginning of operations to the present time the plant has treated some 67 thousand tons of ore having an average copper content of 1.142 pct, of which 0.605 pct has been in the form of oxidized copper minerals. The plant is currently being operated at the rate of 11,500 tons per day, 7 days per week. However, this tonnage is produced in 6 days of mine operation. The average current grade is approximately 1 pct copper, of which about 50 pct is present as oxidized or acid-soluble copper. Close control of metallurgical procedures is a vital factor in operation of the plant and is in turn dependent upon careful regulation of feed. An excess of sulphide copper requires the presence of more ferric sulphate in the leaching solvents. On the other hand, an excess of ferric sulphate in the presence of a low sulphide feed seriously reduces the efficiency of electrolytic precipitation in tank house operations. This condition must be avoided at all costs. An additional factor must be considered. It is known that the sulphide content is predominant in the ore which remains in the reserve. To maintain the necessary sulphide-oxide proportion, so that the entire reserve will mine out at both a grade and a sulphide-oxide ratio that will be permissible throughout the remaining life of the property, it is obvious that the oxide reserve must be currently preserved to as great an extent as possible. Fortunately much of the oxide reserve is found in the open-pit operation. This happy circumstance adds flexibility to the procedure and makes it possible to maintain the close regulation necessary to insure best overall results, both mining and metallurgical. The two ore streams from the pit and underground operations join at the coarse-crushing plant, and proper control must be exercised before the ore reaches this point. The open pit is currently providing about 55 pct of the ore and underground operations the balance of production. Both operations are under a single superintendent so that the closely interrelated problems may be more readily controlled. The least flexible of the two producing units is the underground mine, where the mining method is block caving. Although a block of ground may be undercut and developed, characteristics of the material determine its caving action. The ore in the chutes must be drawn. The area currently mined from underground is in a zone predominately sulphide and is generally

Jan 1, 1953

[ ]

Jan 1, 1938

By F. E. Streigert, J. H. Mallery, A. H. Geisler

The existing data on precipitation in Cu-Be alloys have been reconciled with some new data to present a more complete and rational analysis of the atomic rearrangements involved in the process. Two different coherent precipitates were proposed. Each is responsible for a type of diffuse X-ray diffraction effect. THE nature of the atomic rearrangement involved in the precipitation of the compound y-Cu-Be from supersaturated solid solutions of the copper-base alloys has been the subject of two extensive investigations.'-" he precipitate in this alloy system has a rather simple structure; at equilibrium it has a body-centered cubic unit cell with copper atoms on the corner sites and beryllium atoms on the center site. While a simple mechanism would be expected to obtain for the precipitation process, those which have been proposed do not adequately explain all of the reported data. The purpose of the present report is to rationalize some of the previous observations and to contribute new data on the subject obtained by the usual techniques of structure analyses. The Cu-Be system of alloys represents one of the most extensively investigated precipitation systems, so a detailed review of the pertinent literature on structure is in order. Striations: Since one of the important features of the mechanism—the habit plane—is determined by microscopic examination, microstructural features that have been observed should be considered at this time in order to assess their role in the precipitation process in Cu-Be alloys. One of the most prominent features appears as regularly oriented markings or stripings (ripples or striations) across the crystals on a suitably polished and etched sample of the aged alloy. These have been observed and interpreted by many workers. Masing and Dah14 observed striations in both the a and /3 phases of a 2.5 pct Be alloy, and attributed them to the beginning of the precipitation of very fine y crystals along favored planes of the a matrix and to the local decomposition of the £ crystals into a plus y. These markings were apparent in both the a and /3 phases of the micrographs given by Smith5 for a 2.75 pct Be alloy, while Moore" detected them in the a matrix phase using polarized light. Desch7 attributed the markings to fine precipitate particles lined up on a family of matrix planes like Masing and Dahl had done, and he identified the planes as those of the (111) family, the slip planes of the matrix. The striations were presumably the structure which Northcott- eferred to as "martensitic." He found that this structure was present in samples that had been aged under widely different conditions with hardness values ranging from 160 to 400 VHN. Later Guinier and Jacquet' also found striations in both the a matrix and secondary /3 phase. Their analyses showed that the striations were along (110) planes of the matrix phase, apparently in contradiction of the results of Desch. They found that the striations were developed during aging on the surface of a specimen that had been polished prior to aging.' On this basis they concluded that the striations represented mechanical deformation by slip along (110) planes of the matrix resulting from precipitation stresses.'" Similar but fainter striations were observed in the same manner on an A1-Cu alloy sample, in which the change in volume was much less than for Cu-Be alloys and

Jan 1, 1953

By H. F. Hebley

In recent years, especially in the last decade, great interest has been shown and many advances have been made in the preparation and cleaning of coal. In the major coal-producing countries, the percentage of tonnage cleaned has been increasing ever since 1924. As separating media, both liquids and gases are used, these generally being water and air respectively. Some systems, instead of obtaining separation by the velocity of the medium in which the coal is cleaned, depend on the density of water mixed with sand, or coal dust and shale, or with chemicals such as calcium chloride. In studying the results of coal-cleaning equipment, it will be observed that the efficiency of the cleaning apparatus lowers as the size of the coal decreases. This inability to obtain any marked improvement in the fines has been partly responsible for the installation of dedusting equipment, to remove the fine sizes from the raw coal prior to cleaning. When considering the possibility of installing dedusting equipment, many factors must be taken into account. Very often, but not always, both the ash and sulfur content of the coal increase as the coal size decreases. When bituminous coal, containing soft powdery fusain, is subjected to a wet washing process, the porous fines of the fusain remain in the small coal or in the wash water and delay the dewatering of the washed coal and increase the difficulty of clarification in settling tanks or thickeners. When a dedusted coal is cleaned by a wet process, the sludge recovered from the settling tank often runs so high in ash that the sludge can be discarded without further treatment and still the loss is small. Where treatment of the sludge is desired, however, froth flotation may be used to advantage if the size of the feed is below 1/10 in. Dust from the deduster can be treated in a similar manner. Fusain, which is usually found in the fine sizes, has often a much larger ash content than other coal. Illustrative of this condition is a table of ash contents for the various petrographic constituents of Illinois coal (No. 5 bed) as given by Mitchell' (Table 1).

Jan 1, 1934

By Dorsey Hager

THE possibilities of finding new oil pools in Oklahoma and Kansas are far from promising. In 1916, the only new pools of importance were the Franchot pool near Bixby, the Garber, and the Billings pools in Oklahoma, and the Virgil and Utopia fields in Greenwood County, Kansas. In the first 8 months of 1917, a small pool of unknown extent was opened south of the Stone Bluff pool in Oklahoma, and a pool near Casey, Paunee County, Oklahoma. In Eastern Kansas, interest has been. caused by the sinking of new wells near the old Iola pool, but nothing of magnitude has yet been found. The outlook for new pools is far from encouraging, especially as geological surveys have covered all of Oklahoma and Kansas. There are a few areas where geological surveys throw little or no light on the subject, as exposures are poor, but the chances of finding new pools in such areas are slight indeed, if one can judge from the past history of such areas. So far the geologists have based their opinions largely upon the presence or the absence of geologic structure, such as anticlines, domes, and terraces, but some pools will most certainly be found where no surface structure exists, but where local changes in the sand body favor oil accumulations. However, the possibilities of new pools off structure are small, as fully 90 per cent. of the oil pools are on definite structure. In the past, it is estimated that one test in 150 "wild cats" or new tests has brought in a new field. The writer feels safe in asserting that the proportion will decrease still further, so that but one out of 500 new tests may bring in a pay well in a new area. From now on the principal field of work in Oklahoma and in Kansas will consist in developing the present pools. The years 1915, 1916 and 1917 saw the high peak of Oklahoma and Kansas oil production. The Eldorado and the Augusta oil fields present the largest possibilities for continued production in Kansas. These two pools have been scarcely more than one-third developed, and have greater potentialities than any of the present Oklahoma pools. In Oklahoma, pools of magnitude should

Jan 10, 1917

By B. Post, F. W. Glaser

Three borides of zirconium have been reported: ZrB,l ZrB2,2,3 and ZrB12, 4 The phase relationships, ranges of stability, and some physical properties of these compounds are described. THE zirconium borides differ considerably from one another, particularly with respect to their relative stabilities at high temperatures in the presence of carbon.4,5 ZrB2 is extremelv stable at all temperatures (to the melting point) in contact with carbon. Both ZrB and ZrB12 tend to decompose at elevated temperatures when carbon is present in excess of about 0.5 pct. ZrB forms ZrB2 and ZrC, and ZrB12 decomposes to form ZrB2 and a boron-carbide phase. In the ZrB12 preparation, boron present in excess of that needed to form ZrB2 reacts with carbon, if present, to form carbides, in preference to forming the higher boride. Similar instability of borides, other than diborides of the transition metals of the 4th and 5th groups of the periodic table, has been reported.5,6 special precautions had, therefore, to be taken to minimize carbon contamination in the preparation of ZrB and ZrB12. Reactions below 1400°C were carried out by heating powdered mixtures of zirconium hydride and boron in quartz tubes in a hydrogen atmosphere. For temperatures above 1400°C, reactions were carried out in graphite molds. Carbon contamination from the molds was minimized by employing extremely rapid heating rates to reduce carbon diffusion into the body of the specimen, and by subsequent "shaving" of sample surfaces that had been in contact with the graphite dies. A heating rate of about 2000°C per min was obtained by heating the dies (by direct conduction), using a current of 40,000 amp. Although this type of heating cycle apparently allowed little time for "homogenization," close approximations to equilibrium conditions were usually obtained as a result of the very strongly exothermic reactions between zirconium hydride and boron at elevated temperatures. Reproducibility of results in repeated runs under varying conditions was taken as a reasonable indication that equilibrium conditions had been effectively achieved. Quenching was accomplished by rapidly immersing the entire die, containing the reaction products, in water. Specimens could also be cooled at controlled rates by adjustment of the rate of flow of water through the water-cooled copper electrodes in contact with the graphite dies.

Jan 1, 1954

By Henry P. Ehrlinger, James C. Bradbury

Tripoli is a naturally occurring, very finely divided form of silica found chiefly in some midwestern and southeastern states and used commercially as fillers and abrasives. Definitions Tripoli is a microcrystalline, finely particulate, more or less friable form of silica that appears to be the product of leaching of siliceous limestone or calcareous chert. The term was originally applied to a deposit near Seneca, MO, that resembled material of that name found near Tripoli In North Africa (Hovey, 1894). The two deposits were subsequently found to have different physical characteristics -the North African tripoli, now called tripolite, is a diatomite, composed of the siliceous skeletons of microscopic marine plants called diatoms; the Missouri tripoli contains no diatom remains. The term tripoli, however, continued to be used for the Missouri material and is now applied in a general way to most silica deposits similar to it in characteristics and geologic origin. In commercial trade tripoli is commonly understood to designate material from the Missouri-Oklahoma field; silica from southern Illinois, the other major producing area, is referred to commercially as amorphous silica. Each term, however, may be used commercially for material, regardless of place of origin, that has the characteristics or uses commonly ascribed to the material from one or the other major producing area. For example, in the commodity price listings, Engineering & Mining Journal routinely lists under Tripoli, prices "f.o.b. Elco, IL" and "f.o.b. Seneca, MO, and Rogers, AR," and under Silica, amorphous, prices "f.o.b. IL," and "f.o.b. bierks, AR." Amorphous silica, the commercial designation given to southern Illinois tripoli, is, like the term tripoli, a misnomer. Mineralogically, the southern Illinois deposits are composed of microcrystalline quartz, and no amorphous material has been detected during X-ray and scanning electron microscope investigations (Leamnson, Thomas, and Ehrlinger, 1969; Thomas et al., 1970; Keller, 1978). Soft silica is another term that has been applied to Illinois and Tennessee tripoli, presumably to distinguish it from the more compact Missouri material. It has also been used in the ceramic trade to distinguish tripoli from "hard" silica, or silica flour, produced by pulverizing silica sand (Heinz, 1937). Rottenstone, produced commercially in Pennsylvania, is similar to tripoli in that a major constituent is finely particulate silica, and its uses are much the same as those of Tripoli-as abrasives and fillers. The origin of rottenstone also is similar to that of tripoli-decomposition of a siliceous sedimentary rock. The parent rock is defined as a siliceous limestone (Gary, McAfee,, and Wolf, 1972; Thrush, 1968) or as shale. Heinz (1937) quotes a brief statement describing the Pennsylvania deposits -"a black impure shaly limestone grading into black shale"-but does not identify the source of the statement. For convenience, rottenstone is included with tripoli in the reporting of production statistics in US Bureau of Mines (USBM) Minerals Yearbooks. Other materials that have been called tripoli include siliceous deposits in San Bernardino County, California (USBM Minerals Yearbooks, 1934-1941) and in Nevada (Chandler, 1960). These, however, differ in composition and/or origin from tripoli and, therefore, should not be identified by the name tripoli.

Jan 1, 1983