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By R. F. Pilgrim

A digital computer program to mathematically simulate the effect of limited changes in feed rate in the range of 80 to 95 tph on a plant-scale wet grinding circuit has been developed and tested. The circuit studied included an 8-ft-diam X 12-ft rod mill operating in open circuit and feeding two parallel 12-ft-diam x 10-ft pebble mills, each one operating in closed circuit with an 8 X 32-ft rake classifier. The simulation is an empirical one based on two sets of data collected manually from the operating circuit under what was said to be steady-state feed rates of 80 and 95 tph with all other operating variables also at steady state. The procedure is a combination of several published approaches to the modeling of grinding mills and classifiers and it is applicable to a wide range of circuits. The program permits the computing of the size distributions of all feeds and discharges of all grinding units and classifiers in the circuit for a specified feed rate. The data used in this report for demonstrating the program are unsatisfactory since the circuit was not operating under steady-state conditions when it was sampled. Consequently the circuit model parameters could not be accurately estimated. The predictive power would be greatly improved if new data were obtained under true steady-state conditions.

Jan 1, 1973

Within the last century, and largely during the latter half of it, the increase of our knowledge of the development of man, both in his search for a livelihood and for power, and in the growth of his reason and conscience, has been greater than all we had known before. The great interest in all kinds of archaeological work and the many excavations made of buried and long forgotten places has put at our disposal historical records-not available, and in many cases not known before, and a study of these and other records of human progress from paleontological and geological sources has given us a much broader view of what we call "civilization" than was possible even a short time ago. The old idea that men were created with fully developed minds, speech and reason has yielded to the view that in the upward progress of the human race the development of the mind and reason has been a comparatively recent occurrence, as we think of the half million, and probably more, years that have passed since our earliest records of man were made. The traits that come to us without effort

Jan 1, 1939

By P. G. Linder

The mechanical concentration of ores has not attained any considerable extent in Sweden, by reason of a scarcity of ores calling for this kind of treatment. Of rich iron-ores there is still an abundant supply; and magnetic concentration, which in the future undoubtedly will become of great importance, not being as yet demanded by necessity, has not advanced beyond a few experiments. At the copper-mines mechanical concentration has been superseded by chemical processes; the lead mines are worked out; and it is (with one exception) only the mines producing blende, or blende and galena intimately mixed, that have adopted mechanical methods for enriching their low-grade ores. While the concentrating-plants in Sweden are few and their output is comparatively insignificant, the methods employed, the general features of the work and the results obtained under extremely unfavorable conditions, may offer some points of interest to persons who are engaged in this branch of industry and have similar problems to deal with. Before going into a detailed description of the several plants, I will offer a few remarks that hold good for all of them and constitute a general review of Swedish concentration and its conditions. At all the works the ore to be treated is a mixture of blende and

Jan 1, 1895

By J. Y. Oldshue

INTRODUCTION The field of fluid mixing involves many different kinds of process objectives. In order to classify these objectives, Table 1 gives a listing of five basic application categories, gas-liquid, liquid-solid, liquid-liquid, miscible liquids, and fluid motion. However, each of these areas can be broken up into two different concepts one involved with uniformity of solids or liquids as a criteria, and the other involved with chemical reactions or mass transfer. The things that we would do to design a fluid mixing for solid suspension are quite different from things that we would do to design a mixer for heat transfer or gas-liquid mass transfer. Therefore, there are really ten separate mixing technologies. Each of these areas has its [ ] own principles of fluid mechanics, scale-up techniques and application experience. We will take a look at each of these areas and look at some of the ways that we can handle fluid mixing applications which.

Jan 1, 1979

By D. K. Atwood

Experiments resulted in a satisfactory laboratory method for restoring permeability to clay-containing cores damaged by fresh water. Clay contents of a number of field cores were measured, and permeabilities of plugs from these same cores were then deliberately reduced with fresh water. This damage is attributed to swollen and dispersed clays occupying the pore space. After damaging, a number of experiments were performed to meaJure the amount of damage and to establish some means by which permeability could be restored. The experiments included flooding the damaged cores with water-miscible fluids such as salt water, acetone, isopropyl alcohol and ethanol. Permeability was not successfully restored in these experiments. However, part of the damage was repaired by flooding with oil; when water was removed by distillation in the presence of immiscible fluids such as air or toluene, permeability was completely restored. This evidence suggested that swollen and dispersed clays could be collapsed to their original volume by strong interfacial and capillary forces. It was further postulated that the required forces could be generated by flooding the damaged cores with a solvent partially miscible with water. The flooding experiments were repeated using n-hex-an01 as the partially miscible solvent. Permeability was restored to five of six damaged cores and substantially increased in the sixth. A large fraction of the restored permeability was retained even after water saturation was raised to its original value with 12 per cent salt water. INTRODUCTION Sharp reductions in permeability often occur when relatively fresh water contacts clay-containing formations during drilling and workover operations. These permeability losses are caused by removing inorganic ions from the environment surrounding the clay, and consequent swelling and/or dispersion of clay minerals into the available pore space.' This phenomenon is generally termed clay damage, fresh-water damage, or simply formation damage; it causes large losses in current revenue by preventing oil wells from making their allowable production. Attempts to repair the damage and restore permeability by flowing salt water solutions or brines through clay-damaged cores containing montmorillonite have been unsuccessful.' This irreversibility is thought to result from formation of brush-heap, or edge-to-face, structures when the dispersed clay is flocculated. The brush-heap structures occupy much more space than the close packed domains present before damage.' One solution of the problem is to destroy the clay-water brush-heap and thus restore permeability. Because no satisfactory method existed for restoring permeability to clay-containing formations damaged by fresh water, the work described in this paper was under taken. The laboratory experiments generally consisted of deliberately damaging fresh cores containing clay and then attempting to repair this damage by various means. Results indicate that generating strong interfacial forces within the pore space of damaged cores collapses the clay brush-heap and restores permeability. These forces are most conveniently generated by flowing partially water-miscible solvents, such as n-hexanol, through a core. THEORY OF THE DAMAGE PROCESS The most common clay mineral groups known to cause permeability damage to formations are the mont-morillonites, kaolins, chlorites and illites. These clays are constructed of particles which can adsorb water on their surfaces and edges and, in the case of montmorillonite, between layers of the basic particle itself. This adsorption increases as water salinity decreases. At low salinities the particles disperse into the aqueous phase. When the clays present in the formation are kaolin, chlorite and illite, dispersion accounts completely for permeability damage to porous media. However, unlike the other clays, montmorillonite particles can imbibe water and adsorb ions between layers of sub-particles, or platelets. These platelets have net negative charges on their faces and are held together by exchangeable (or removable) cations such as Na and Ca decrease in ion concentration (salinity) in the fluid surrounding a particle causes migration of water into the clay layers and disperses the basic particle, while diffusion removes the original exchangeable ions from between the platelets. Once these ions are removed, the facing negative platelets repel each other, causing the montmorillonite to swell until, for all practical purposes, the individual platelets are dispersed. For this reason, fresh-water* damage is much more severe in sands containing montmorillonite than it is in sands containing other clays. Many investigators have shown that even trace amounts of montmorillonite can be responsible for marked reduction in the permeability of reservoir sands in the presence of fresh water." ." Monaghan and others have shown that fresh-water damage in montmorillonite-containing cores cannot be

Jan 1, 1965

By O. M. McRae. Discussion by R. W. Jones

R. W. Jones (Senior Exploration Geologist, Standard Oil Co. of California, Box 250, Seattle, Wash.) -Mr. McRae6 and his colleagues are to be congratulated for providing a more coherent structural synthesis of the complex structure in the Courtland-Gleeson area, Cochise County, Arizona, than the "gigantic thrust breccia" concept of Gilluly. 4 However, a few problems of interpretation remain. It is the intent of this note to point out some of these problems, and, drawing on my own work in the area as well as the work of McRae6 and Gilluly, 4 to suggest some interpretations which differ from those previously published. GRAVITY SLIDES In an unpublished manuscript (Jones5) I previously argued that most of the complex structures in the Courtland-Gleeson area can be most reasonably interpreted in terms of gravity sliding caused by uplift and eastward tilting of Jurassic intrusives and associated Paleozoic rocks. Although the field work and drill hole data described by McRae6 provided excellent documentation for two important gravity slides, McRae6 interpreted the basic structure in the Courtland-Gleeson area in terms of major eastward directed thrusting. I continue to disbelieve the

Jan 1, 1967

By J. C. McCarthy, J. B. Stone

AT Fresnillo a series of veins that has yielded very large quantities of silver and other metals has been developed over a length of 6500 ft. and to a depth of over 3000 ft. In the course of this work striking changes in the mineralogy and metal content of the principal veins have been disclosed and are well illustrated by assay data and ore reserve calculations. This paper describes those changes and suggests their bearing on theories of ore deposition. LOCATION The Fresnillo mines and the adjacent city of Fresnillo are in the central part of the state of Zacatecas, 35 miles northwest of the capitol city of Zacatecas, once a great silver-mining center whose total production is said to place it fourth in the world. Another famous old silver district, Sombrerete, lies northwest of Fresnillo. Fresnillo is connected by a 5-mile branch with Fresnillo station on the Mexican National Railways line from Juarez to Mexico City. Lying near the southwestern edge of the central plateau of Mexico, Fresnillo ís surrounded by a semi-arid rolling plain from which rise widely scattered low hills. One of these is Proaño hill, an inconspicuous elevation rising barely 300 ft. above the plain, but in and around Proano hill are the Fresnillo mines, and it is marked now by a great gash cut by glory-hole mining. HISTORY According to an account written in 1834 by Francisco García, then Governor of the state of Zacatecas, Fresnillo was discovered in 1554, and a presidio was established there in 1568 to protect travelers on the road between Zacatecas and Sombrerete. Little is known of the earliest mining at Fresnillo, which seemingly began soon after its discovery, but by piecing together various accounts, it appears that mines there were working in 1717 and were notably active ín 1751 under an administrator named Murguía, who left detailed notes describing them. In 1757, however, the mines became inactive because of difficulties with creditors and no doubt also because of increasing water troubles, and they remained abandoned until 1830. In 1830 the mines at Fresníllo became the property of the State of Zacatecas because the interest of Governor García had been aroused by the long disregarded notes of Murguía. Under García's energetic leadership the mines were reopened, and silver production began in 1832 ín spite of serious difficulties, including abnormal rains and an epidemic of cholera. In 1835 English capital was sought to allow installation of steam-driven Cornish pumps at the two principal shafts and to build the great hacienda de beneficio (the present Proaño hacienda). The company formed in 11835 (Cia. Zacatecano Mexicana) operated successfully until 1872, when its career was brought to an end by the political and economic disturbances

Jan 1, 1942

By B. W. Gandrud

WET-PROCESS coal-washing tables as we know them today have been in use in this country for approximately 25 years. The literature records only a few table installations worthy of note prior to adoption of the present-day differential-motion table. According to Phillip,1 six Campbell bumping tables were being operated by the St. Bernard Coal Co., Earlington, Ky., in 1893. As late as 1923, according to Richardson, 2 such tables were in operation in the Rosedale washery of the Cambria Steel Co., at Johnstown, Pa. Bumping tables probably were not used to any considerable extent except in the plant at Earlington, and at two or three plants in Pennsylvania, but they may be considered as. forerunners of the present-day coal-washing table. The transition from bumping tables to the type of tables now in use signalized a revolutionary change in table design. The advantages of the new design over the old were so outstanding as to make its adoption inevitable. BUMPING TABLES Bumping tables, as the name implies, utilized a bumping action for conveying the refuse and discharging it over the refuse end. The tables were hung from rods attached to overhead supporting beams. A shaft and cam arrangement at one end of the table served as the actuating mechanism and imparted to the table an endwise, back-and-forth, swinging motion. A bumping block was fixed in the proper position at the shaft end, so that the table would strike against it at the end of each backward swing. The hanger rods or stirrups were so adjusted as to give the table a slight uphill slope toward the refuse end; that is, the end next to the driving mechanism. The feed box was near the upper end of the table and designed to spread the mixture of coal and water over the width of the table. Wash water was added a short distance below the feed box. With the table in motion and coal mixed kith water being fed to it through the feed box, a certain amount of stratification took place, depositing heavy refuse at the bottom of the bed in contact with the surface of the table. Constant bumping and a certain amount

Jan 1, 1950

By Milan Matula

One of the main characteristics of the development of rock mechanics in some countries is a close cooperation between experts in rock mechanics and workers in related fields, including soil mechanics and engineering geology. The purpose of this chapter is to outline the contribution that engineering geology can make to rock mechanics and to present a few examples of engineering geology studies that have been used in solving some practical rock mechanics problems. Engineering geology investigations dealing with the influence of geological factors on the physical properties of rock materials and rock masses fall into three main categories : 1) Systematic study and correlation of the physical properties of the main rock types with the petrogenetic evolution that caused the differences in the properties of these various rock types. 2) Study of the heterogeneity and anisotropy of both rock materials and rock masses. 3) Delimitation of rock masses which are approximately uniform in physical properties (quasihomogeneous units). Delimiting of the quasihomogeneous rock masses is the main contribution that the engineering geologist can make to rock mechanics. This delimiting is based on the evaluation of many complex geologic factors, not on test results alone, and therefore is most effectively done by trained engineering geologists. The foregoing types of studies are being used in Czechoslovakia for several purposes, including : 1) the compilation of regional engineering petrologic data-that is, the systematic definition of the main rock types of the country in terms of their representative physical characteristics;

Jan 1, 1970

By D. R. Walker, M. C. Shaw

THE laws of comminution of Kick and Rittinger have been debated for many years. Certain data obtained from ball mill and drop tests are found to be in approximate agreement with Rittinger's law while other data would seem to support Kick's law. In all these tests the energy required to produce a wide variety of particle sizes has been studied. Surface area has also been measured with considerable difficulty, at first because it was thought that the energy associated with crushing was that required to create new surface, later because of precedent and because a more fundamental variable was unknown. Tests made with the machine shop type of grinding process show that normally brittle materials that are usually crushed can behave like the more ductile metals. Brittleness is then a relative property largely dependent on specimen size and stress state. The machine grinding operation offers a convenient means for studying the comminution of materials in which the important size variable retains its identity. The energy required to grind a certain volume of material is shown to be strongly de- pendent on size. Kick's law is found to hold very well for particles below 1 micron in size, while Rittinger's law holds approximately in the comminution of larger particles. While a physical origin of Kick's law is established in terms of the theoretical strength of materials having a perfect lattice structure, there is found to be no physical basis for Rittinger's law.

Jan 3, 1954

By Y. C. Liu, G. A. Alers, S. S. Choi

In searching for an explanation for the obvious difference between the copper and the brass type of rolling texture, it is common practice to look for correlations with other properties. For example, there are obvious differences between copper and brass in the critical resolved shear stress, the extent of easy glide or stage I, and the amount of "overshooting)) during single-crystal deformation.' Also, the slip lines in copper are fine and wavy while those in brass are more coarse and better described as slip bands.' Since neutron irradiation is known to make these properties in copper change in such a way as to resemble brass,2'3 an excellent test for these possible correlations is to see whether neutron irradiation produces a corresponding change in the texture, i.e., whether irradiated copper develops a brass-type rolling texture. The experiment would also answer the more important question of whether or not lattice defects like those introduced by neutron irradiation have any effect on the development of rolling textures in fcc metals. Experimental studies using conventional X-ray pole figure techniques are inconvenient because the X-ray detection system must be modified to discriminate against the radioactivity which is induced in the specimen by the necessarily long exposure to neutrons. Nevertheless, some texture determinations have been

Jan 1, 1968

By Colin G. Fink, Leslie G. Jenness

Tantalum and columbium occur together in tantalite and columbite ores, which may be considered as ferrotantalate (FeTaz06), with part of the iron and tantalum replaced by manganese and columbium respectively, the general formula, therefore,becoming (Pe, Mn)O.(Ta, Cb)2Os. The ratio of tantalum to columbium is not fixed; the amount of tantalum may vary from one-third to three times that of columbium. Minerals having a high content of tantalum are called tantalite, while those possessing larger amounts of columbium are classified as columbite ores. These minerals are found in pegmatites and often occur in veins associated with cassiterite and wolframite, and may contain small amounts of tin, tungsten, titanium and si1ica. l Methods of Extraction Several methods have been proposed for the extraction of tantalum and columbium from their ores, among them being: 1. Fusion with Potassium or Sodium Bisu1fate.—The finely ground ore is fused with potassium bisulfate, after which the mass is boiled with water and the fusion repeated several times. The residue finally resulting is digested with ammonium sulfide to remove traces of tin and tungsten, boiled with hydrochloric acid, filtered and washed. These oxides are then dissolved in hydrofluoric acid, the silica evolved as silicon tetra-fluoride and the hydrofluoric acid solution used for the potassium double fluoride separation of tantalum. 2. Fusion with Sodium Carbonate and Sodium Nitrate.2—This fusion renders the tantalum and columbium soluble, and they are extracted

Jan 1, 1931

By James R. Jones

The concern for air pollution goes back centuries as will be seen from this quotation: "Strife and coal, it seems, have a hand-in-hand historical relationship. It was thought by some . . . in the Middle Ages that burning coal filled the air with dangerous poisons. So great was the concern that in 1306 King Edward I of England passed the first and unquestionably the harshest, air pollution legislation edict that history will record. His proclamation declared the use of coal an act punishable by death." As related to coal mining the air pollution problem is primarily that of its customer when using the fuel. Thus the major impact relates to markets for coal rather than the actual mining operation itself. In the vicinity of the coal mine the problem is principally related to fugitive dust from roads, transfer facilities, loading facilities, crushers. etc., and particulate matter (dust or fly ash) from thermal dryers and air cleaning tables. FUGITIVE DUST Most state air pollution regulatory agencies now have rules and regulations requiring control of fugitive dust. This refers to dust generated from normal processing operations. A typical air pollution control agency regulation reads as follows: "Fugitive Dust" "No person shall cause, suffer, allow, or permit any material to be handled, transported, or stored; or a building, its appurtenances, or a road to be used, constructed, altered, repaired, or demolished without taking reasonable precautions to prevent particulate matter from becom-

Jan 1, 1973

By G. T. Davis, C. C. Mattax, M. O. Denekas

The effects of crude oil cornponents on the wellabil-ities of sandstone and limestone were investigated. Fractions containing cornponents differing in molecular weight and molecular structure were obtained from crude oils by distillation, extration and chromatography. Individual fractions were then tested for their effects on rock wettability. Tests indicate that sundstone wetta-bility may he changed by a complex variety of surfactants varying both in molecular structure and molecular weight. Limestone appears to be particularly sensitive to basic, nitrogenous surfactants. INTRODUCTION Investigations in recent years have shown that petroleum reservoir rock wettability can exert a significant influence on the efficiency with which oil can be produced by water flooding. While most reservoirs are presumably water-wet, they niay range in their degree of water-wettability from near-neutral to strongly water-wet.'" Reservoir wettabilities other than strongly water-wet are likely to be induced by adsorption of surface-active components froni the crude oil on the pore walls of reservoir rock.:' Little is known, however, about the nature of the surface-active materials which are likely to be adsorbed by the reservoir rock. Due to the complexity of crude oils. attempts made in the past90 isolate these surface-active components have met with only limited success. It is probable that many different types of surface-active materials arc indigenous to crude oils and that many of these may be adsorbed to varying degrees by reservoir rock. This was cxolored in the studies discussed in this paper. The over-all objective in these studies is to ascertain whether the wettability of a given reservoir can be determined by examining the surfactant content of the reservoir crude. To this end, crude oils were examined to determine the variability of indigeneous surfactants with regard to chemical type and molecular weight. Crude oils were separated by distillation into fractions differing principally in molecular weight, by chroma-tography into fractions containing compounds differing in polarity, and by solvent extraction into nitrogenous and non-nitrogenous fractions. Individual fractions were then tested for their effects on the wettabilities of sandstone or limestone rock samples. EXPERIMENTAL PROCEDURES Fractionation of the Crude Oils Samples of Miocene, Eocene and Jurassic crudes were distilled at temperatures not exceeding 200°C. The final stages of distillation were completed in a molecular still at pressures down to three microns of mercury. Fifteen to 30 fractions were obtained from each crude oil. These cuts were sufficiently broad that separation can be considered to have been effected principally on the basis of the molecular weights of the constituents of the crude oil. A considerable portion (20 to 40 per cent) of the crudes would not distill under these conditions. The residues were recovered and tested with the other fractions. Fractions differing in polarity were separated from a crude of Pennsylvanian age and an extracted sample of Miocene oil by chromatography, using a solid adsorbent. Since surfactants are, for the most part, polar compounds, chromatography should separate many of the surfactants from the crude oil. Such a separation should provide fractions containing compounds differing in molecular structure. Nitrogeneous compounds were extracted from Miocene crude oil with a solution of sulfuric acid in meth-anol. The residual oil was further processed by chonia-tography. Each of the fractions obtained by thesc procedures was dissolved in a non-polar solvent (xylene) and diluted to its original concentration in the crude oil. No attempt was made to maintain an anaerobic atmosphere above the samples while they were being dissolved. These solutions of the fractions were then tested for their effects on the wettability of sandstone and limcstone as discussed in the next section. Measurement of the Effects of Crude Oil Fractions on Rock Wettability No entirely satisfactory method for measuring rock wettability has yet been developed. All methods used are empirical. The imbibition test was used in these studies. This test is based on the tendency of a rock to imbibe the wetting phase spontaneously. For example, if a strongly water-wet rock is first saturated with oil and then placed in water, the water will quickly invade the rock by capillarity and much of the oil will be displaced. If the rock is slightly water-wet, water irnbibition will proceed more slowly and, in many instances, considerably less oil will be displaced. A water-saturated, oil-wet rock will imbibe oil. The initial rate with which water (or oil) imbibition takes place indicates, qualitatively, the degree of water (or oil) wettability of the rock.

By T. F. Mueller, P. A. Witherspoon

For the case of an infinite radial system operating at constant terminal rate, the reservoir engineer often uses the "point source" solution of the diffiusivity equation to study pressure interference effects. At early times and at short distances from the inner boundary these solutions are invalid. The amount of error is often not precisely defined because of mathematical difficulties. Work presented here shows that, if dimensionless time is defined appropriately, previous solutions of the pressure equation can be displayed .as a family of curves on one chart. These solutions include the point source solution (referred to in the field of hydrology as the Theis solution) and other solutions obtained with digital computer methods. With these curves, an exact evaluation of the pressure drop within a reservoir or an aquifer can be made by the engineer. Examples of field problem solutions are presented. In most reservoirs the error involved when the Theis solution is employed is often negligible; whereas, in the calculation of interference effects in an aquifer, a substantial error can occur through such an approach. INTRODUCTION Flow equations are used in petroleum engineering to study the behavior of individual wells and reservoirs. In the case of wells, the pressure response at the wellbore face is the major point of interest; whereas, in the case of reservoirs, the pressure response at the interface of the aquifer boundary is sought. To aid in such studies, the flow equations have been solved in terms of the behavior at these two inner boundaries. Only limited work has been published in regard to the pressure conditions away from these points, i.e., within the reservoir or aquifer. Theis and Mortada are among the few who have reported on this problem. The Theis approach employs the exponential integral and is valid for pressure conditions that occur some distance away from the flow disturbance. It is derived from the concept of a point source, as opposed to a flow across some finite area. The Mortada results, on the other hand, are valid at all points within the reservoir or aquifer. They are presented in terms of dimension less ratios of the radius where the pressure is desired to the radius where the flow rate is measured. Their main use, in the past, has been in aquifer studies. The published results are presented in the form of graphs that are limited to a maximum radius ratio of 64. These graphical results are cumbersome to interpolate at non-integral radius ratios, so that one may be forced to utilize a rather involved analytical expression presented by Mortada. BASIC EQUATIONS The solutions of Mortada and Theis are both based on the diffusivity equation as applied to the case of an infinite radial system subject to a constant terminal rate. The equation is obtained by combining the material balance equation with Darcy's flow equation. The assumptions implicit in the use of this equation are as follows: (1) a single fluid is present that occupies the entire pore volume; (2) the reservoir is horizontal, homogeneous, uniform in thickness, and of infinite radial extent; (3) compressibility and viscosity of the fluid remain constant at all pressures; and (4) fluid density obeys the equation Using the diffusivity equation in situations where the above conditions do not hold will result in errors. These errors (not discussed here) but only the errors which arise in the solution of the equation itself. The diffusivity equation for the homogeneous reservoir conditions cited above can be written in cylindrical coordinates, as To obtain a dimensionless equation, so a single solution can be used for applications of different porosity, permeability and fluid properties, the following transformations are usually made: After these transformations are made, Eq. 3 .can be written in dimensionless form, as MORTADA SOLUTION One solution of Eq. 6 has been given by Mortada.

Jan 1, 1966

By F. Julius Fohs

Centrally located with relation to the largest iron- and steel-producing districts of the United States, the fluorspar-deposits of Kentucky possess increasing interest and importance. As typical of the numerous fluorspar-mines of Kentucky and Illinois, I have selected for description the Memphis, because it and others of its immediate group exhibit the conditions characteristic of all. I. The Memphis MiNe. This mine lies 5 miles NW. of Marion, in Crittenden county, Kentucky, a station on the Chicago and Nashville division of .the Illinois Central R. R. For the first mile and a half out of Marion we see only Birdsville or Middle Chester sandstones of Mississippian age. Then we cross a fault of about 850 ft. displacement, and the Ste. Genevieve oolite sets in. Beyond the fault, oolite is the predominant rock, except that the hills to the north have a capping of Cypress or lowest Chester sandstone, 80 ft. below which is an outcrop of from 6 to 10 ft. of Ste. Genevieve (Rosiclare) sandstone. Occasional sink-holes are noticed, and as the mines are approached evidence of faulting is again seen. A line of .crude head-frames and open-cut dumps, extending for more than a quarter of a mile, marks the Klondike vein. The open-cuts are from 15 to 20 ft. deep, and in most of them, from the surface down, was found the reddish gravel which is really fluorspar—some of it white or purple and crystal-clear (if the red clay is washed off), and some carrying iron and silica, and stained by waters from the decaying limestone walls. In one of these cuts, at a depth of 20 ft., white and purplish honey-combed fluorspar was found, in which the larger cavities are due to the leaching of limestone and calcite, and the minute ones to the leaching of zinc-hlende.

Jan 1, 1910

By D. E. Norquist, J. E. Moeller

The results of wear on marked balls, 4, 31/2, 3, and 2 in. diam are given. All balls were forged steel of practically the same chemical analysis and hardness. The results indicate that balls in a given mill for a given length of time will have equal diameter losses, regardless of size.

Jan 1, 1950

By W. B. Mather

A RKANSAS is not only a geologist's paradise, but Ait is also particularly fortunate in possessing a wide variety of mineral resources. The future mineral production and mineral industry of Arkansas, like the other states in Mid-America, will probably depend to a large degree on efforts to increase the exploitation of the non-metalliferous deposits of the state. The term nonmetalliferous, as used in this paper, embraces all types of mineral deposits, except fuels, water, and those deposits from which, after bene-ficiation, metals are ultimately derived. For example, bauxite is the ore of aluminum, but a considerable portion of the bauxite mined eventually is employed in the production of nonmetallic alumina, an important oxide in the abrasive and ceramic industries. The bulk of the production, however, becomes metallic aluminum and therefore this type of mineral resource is considered metalliferous and is omitted from this paper. Arkansas' nonmetalliferous deposits are of many different types, too numerous to discuss in detail in a single paper; therefore, only their salient features are presented. Many types of deposits such as limestone, glass sand, novaculite, shale, and sandstone are exposed over wide areas, providing inexhaustible reserves. Other types of deposits, such as barite and tripoli, contain large reserves which certainly are not unlimited. Still other types of deposits, such as celestite, kaolin, and vermiculite, appear to occur in small isolated deposits containing relatively small reserves. Of course, all of Arkansas' nonmetalliferous deposits probably have not as yet been recognized, nor have all of the known deposits been prospected, tested, and evaluated. Various types of deposits are too low grade or too limited in extent to be profit- ably produced by today's standards. In the case of other deposits, the known uses are few in number, thus acting as a retarder to their development. Due to anticipated technologic advancements, the future demands of industry are not expected always to be the same as they are today, and therefore idle deposits or those of current limited production may readily become the important revenue producers of the future. The types of nonmetalliferous deposits discussed here include: clays, shales, and slates; silica deposits including glass sand, novaculite, tripoli, sandstone, chert, and quartz crystals; limestone and dolomite; barite; gypsum; celestite; nepheline syenite; green-sand; phosphate; vermiculite; fuller's earth; ben-tonite; diamonds; sand, and gravel. The location of the various types of deposits are presented on the accompanying map (fig. 1). Symbols indicate the general area of occurrence. Many deposits, such as limestone, shale, novaculite, and so on, are represented by formations which could only be properly shown on a geological map. In these instances only active deposits or those of exceptional merit are indicated by symbols on the map. A general northeast-southwest line divides the interior highland from the Gulf Coastal and Mississippi Alluvial Plains of south and east Arkansas. The data presented in this paper are only a surnmary of a portion of a more comprehensive survey and study of the natural resources of the entire state.' The study was sponsored and underwritten by the Arkansas Power and Light Co., Little Rock, as a public service to the state and its residents. Permission to present some of the data and conclusions resulting from the survey is gratefully acknowledged. Table I, prepared by the Arkansas Geological Survey from state severance tax records, presents the annual production secured from Arkansas nonmetalliferous mineral deposits. Clays, Shales, and Slates Clays: It is realized that each method of classifying clays is prone to criticism. In this paper, Arkansas' clays of potential value are arbitrarily

Jan 1, 1951

By W. B. Mather

A RKANSAS is not only a geologist's paradise, but Ait is also particularly fortunate in possessing a wide variety of mineral resources. The future mineral production and mineral industry of Arkansas, like the other states in Mid-America, will probably depend to a large degree on efforts to increase the exploitation of the non-metalliferous deposits of the state. The term nonmetalliferous, as used in this paper, embraces all types of mineral deposits, except fuels, water, and those deposits from which, after bene-ficiation, metals are ultimately derived. For example, bauxite is the ore of aluminum, but a considerable portion of the bauxite mined eventually is employed in the production of nonmetallic alumina, an important oxide in the abrasive and ceramic industries. The bulk of the production, however, becomes metallic aluminum and therefore this type of mineral resource is considered metalliferous and is omitted from this paper. Arkansas' nonmetalliferous deposits are of many different types, too numerous to discuss in detail in a single paper; therefore, only their salient features are presented. Many types of deposits such as limestone, glass sand, novaculite, shale, and sandstone are exposed over wide areas, providing inexhaustible reserves. Other types of deposits, such as barite and tripoli, contain large reserves which certainly are not unlimited. Still other types of deposits, such as celestite, kaolin, and vermiculite, appear to occur in small isolated deposits containing relatively small reserves. Of course, all of Arkansas' nonmetalliferous deposits probably have not as yet been recognized, nor have all of the known deposits been prospected, tested, and evaluated. Various types of deposits are too low grade or too limited in extent to be profit- ably produced by today's standards. In the case of other deposits, the known uses are few in number, thus acting as a retarder to their development. Due to anticipated technologic advancements, the future demands of industry are not expected always to be the same as they are today, and therefore idle deposits or those of current limited production may readily become the important revenue producers of the future. The types of nonmetalliferous deposits discussed here include: clays, shales, and slates; silica deposits including glass sand, novaculite, tripoli, sandstone, chert, and quartz crystals; limestone and dolomite; barite; gypsum; celestite; nepheline syenite; green-sand; phosphate; vermiculite; fuller's earth; ben-tonite; diamonds; sand, and gravel. The location of the various types of deposits are presented on the accompanying map (fig. 1). Symbols indicate the general area of occurrence. Many deposits, such as limestone, shale, novaculite, and so on, are represented by formations which could only be properly shown on a geological map. In these instances only active deposits or those of exceptional merit are indicated by symbols on the map. A general northeast-southwest line divides the interior highland from the Gulf Coastal and Mississippi Alluvial Plains of south and east Arkansas. The data presented in this paper are only a surnmary of a portion of a more comprehensive survey and study of the natural resources of the entire state.' The study was sponsored and underwritten by the Arkansas Power and Light Co., Little Rock, as a public service to the state and its residents. Permission to present some of the data and conclusions resulting from the survey is gratefully acknowledged. Table I, prepared by the Arkansas Geological Survey from state severance tax records, presents the annual production secured from Arkansas nonmetalliferous mineral deposits. Clays, Shales, and Slates Clays: It is realized that each method of classifying clays is prone to criticism. In this paper, Arkansas' clays of potential value are arbitrarily

Jan 1, 1951

By Persifor Frazer

It has been the aim of the writer, by measuring his base line on the territory of theoretical chemistry, to attempt to fix by triangula tion certain points within the domain of mineralogy. As the barest first experiment in this direction, a few of the hydrated oxides of iron have been selected, their theoretical construe tion reduced to percentage of the constituents into which the ordinary analytical methods would resolve them, and the results compared with actual analyses compiled from the most reliable sources; the accidental errors being as much as possible eliminated. This method seems to be a simple one and one easily pursued, but, as will shortly appear, it is beset with grave difficulties, all of which the writer does not pretend to have satisfactorily surmounted. In the first place arises the important question, what are we to understand by the hydrated oxides of iron ? In all books of chemistry and lexicons of minerals, the proposition, long ago taught by the earlier chemists, that water might exist in two forms of combination, viz., as water of crystallization or as water of constitution, is tacitly assumed. There is nothing in the principles of the new chemistry which is opposed to this; for (to carry the mind's eye into the process of con struction of the least units into which a definite chemical compound is capable of being divided without losing its characteristic proper ties), however unlikely it may seem, it is, nevertheless, possible that a given molecule of iron may, under certain conditions of heat, pressure, etc., attract to itself as many molecules of the water in which it is natant as: from the relative size, shape, attractive force, etc. of either, it is capable of taking up, and this complex system of associated molecules might oscillate as a physical unit so long as the conditions on which its existence was dependent remained unchanged. Moreover, it is highly probable that the first effect upon such a mole cule produced by physical or chemical forces would be to separate it into two or more simple ones of different kinds, while a further ap plication of these forces might rend asunder the bonds of the simpler compounds themselves.

Jan 1, 1879