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By E. H. Crabtree, J. D. Vincent

Probably no metallurgical process in the history of the mining industry has been responsible for such increased mineral production as has flotation. It has made possible the economic treatment of low grade and complex ores which, with the old methods of gravity concentration, would have been classed as worthless. Starting with the sulfide ores of copper, lead, and zinc, the process has been applied to almost all metallic and nonmetallic minerals. Today, the sulfides of the common metals not only can be readily recovered, but can be separated from each other. Thus, three or four mineral recoveries from the same ore, such as galena, chalcopyrite, sphalerite, and pyrite, are possible. Molybdenite is recovered initially with copper sulfides and the two are subsequently separated. Flotation of metallic gold and of native copper and graphite is being commercially practiced. The carbonates of some of the base metals, principally those of lead, can also be concentrated. Flotation of the oxides, silicates, phosphates, and other so-called non- metallic minerals represents the greatest advance in the art in the last few years. Today, commercial plants are successfully treating such minerals as feldspar, garnet, ilmenite, muscovite, cassiterite, cement rock, fluorspar, phosphate rock, sylvite, and a host of others. Flotation of the various types of iron ores along with other concentration methods is today the subject of a tremendous amount of investigation on the iron ranges. EARLY PATENT HISTORY OF FROTH FLOTATION Although what we call the froth flotation process as distinguished from bulk oil processes was not used commercially until 1905, many investigators had recognized its possibilities long before the twentieth century. The principal patents issued throughout the years give us a method of recording early flotation history. BULK OIL PROCESSES: In 1860, William Haynes patented (British Patent 488) a process for separating oil-wetted sulfide minerals from water-wetted gangue minerals by agitating the dry ground ore with oil and then the mixture with water. In 1877, the Bessel brothers patented (German Patent 42, Class 22) a process where a mixture of graphite ore was mixed with 1 to 10% oil; after adding water, the

Jan 1, 1962

By H. H. Kaveler, Z. Z. Hunter

Variation of the horizontal permeability (parallel to the bedding plane) in the vertical section of reservoir rocks has long been observed as a characteristic of a normally heterogeneous system which reservoir rock represent. The use of a recently developed water injection profile device offered opportunity to measure with a high degree of reliability the rate of inflow of water into Burbank sandstone in wells previously cored. Water injection profiles were not correlative with core permeability profiles in such wells. Apparently the vertical permeability substantially influences the flow between strata in a formation in a manner as to void the usual conclusions that have been drawn from consideration of the horizontal permeability measurements alone. The results obtained in comparing water injection profiles with horizontal permeability profiles suggest that many of the usual production operations based upon "selective" behavior or treatment of rock exposed in well bores need to he re-valuated and re-examined. INTRODUCTION Petroleum reservoir rock are heterogeneous systems. Heterogeneity exists in respect to lithologic character insofar as such rock are composed of distinguishable solid phases. Heterogeneity also exists in respect to certain properties, such as porosity and permeability, that vary due to variation of the physi-cal structure of the rock. Except in exceptional cases, both the horizontal permeability (measured parallel to the bedding planes) and the vertical permeability (measured perpendirularly to the bedding planes) exhibit significant variation in any common source of supply. The variation in horizontal permeability. as reflected by con. analyses. has drawn the greatest attention of petroleum technologists probably out of the general notion that the mass movement of fluids in a reservoir is predimonantly in the horizontal direction. Furthermore, in the usual case, the rock permeability measured in the horizontal direction is greater than that in the vertical. The variation of horizontal permeability of reservoir rock has been the basis for developing a number of operating practices and procedures intended to improve the petroleum production operation. Many such procedures are referred to as "selective" in the sense that the practice is intended to control the flow to a more. or less. permeable interval within the common source of Supply. It is often said that such practices are "tailored" to the permeability profile. The practices referred to involve, among others, the following: selective perforation of casing; selective shooting, acidizing and plugging: plugging back to intervals of low permeability; and, regulation of flow to prevent coning of water or gas, or irregular encroachment of water or gas. Certain expressed notions involving a concept of "by-passing," or "trappingl" that are held to be particularly harmful in causing the avoidable loss of recoverable petroleum have grown from observed variations in the horizontal permeability. Oftentimes estimates of the reserve of a common source of supply are tempered by conclusions relating variation in horizontal permeability to recover-ability of the oil-in-place. Certain conclusions attributed to the significance of the variation of the horizontal Permeabilitv often extend to the design and operation of pressure-maintenance projects involving both water flooding and gas-injection. Many advocate increasing the number of injection wells, advocate maintaining uniform and equidistant input-output well patterns, or advocate so-called "dispersed" gas-drive techniques rather than gas-cap injection because the permeability profile of cored wells is supposed to indicate that "by-passing" or "trapping" would otherwise exist. It is important, therefore, to have an opportunity to test whether the variation in the horizontal permeability found through core analyses of a typical reservoir rock is sufficient to establish the paths of fluid flow in a reservoir. It is particularly important to have an opportunity to determine whether flow at the sand face of a well conforms to the permeability profile as established by core analyses. In that manner, the merit of certain 50-called "selective" operating procedures and other notions may be evaluated. The purpose of this paper is to compare horizontal permeability profiles of wells in the Bartlesville (Bur-bank) sandstone with water injection profiles, for the purpose of showing that there is no correlation between the horizontal permeability of a core and the water intake characteristics of a typical sandstone. GENERAL CHARACTERISTICS OF BARTLESVILLE (BURBANK) SANDSTONE The Bartlesville sandstones of Northeastern Oklahoma are off-shore bar deposits.' Although other reservoirs had different processes associated with their deposition or with the formation of their porous, permeable structure, the l!artlesville sandstones on which these field Fields were made are, in every respect. typical petroleum reservoir rock. The permeability of the Bartlesville sandstones shows a typical variation in both the horizontal and vertical direction. Furthermore, the permeability profile logs of wells in any pool are not correlative, even as between wells as close as 660 ft and 330 ft apart.'. The same condition exists in such sand-tones as the Jones Sand at Shuler' and is the ordinary and usual characteristic of reservoir rock. THE FIELD DATA The data reported herein are those obtained from coring of nine wells on the center of ten-acre locations for the purpose of providing water-injection wells in the Bartlesville (Burbank)

Jan 1, 1952

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 B. D. Thomas

GRAVITY concentration is a general term designating processes for separating and sorting granular material by means of forces that depend on the density, size and shape of the particles. When these forces are applied to the particles the latter are caused to move, those of a given density along one path and those of a different density along another, until ultimately they are sufficiently separated to be removed from the operation of the process. The forces producing this separation are in general complex and, unfortunately, no completely rigorous analysis of them has as yet been devised. The science of the hydrodynamics of viscous fluids deals with the little that is known about the problem. Every observer of nature is familiar with the fact that an object moving in a fluid encounters a force of resistance. We have only to walk against a brisk wind or stir a cup of coffee, or observe the slow fall of a grain of sand in water, to experience directly the fact that such forces exist. The exchange of force between an object and a fluid in which it is moving operates on the fluid as well as on the object. Thus a sailboat may be set in motion by the force exerted by the wind on the sail; but the sail also deflects the wind-furthermore, the water in which the boat floats is set in motion by the force exerted by the boat as it cleaves through the water. The wind is thus enabled to do work on the water through the intermediary of the boat. In general, an object moving through a fluid encounters a force that opposes the motion and also acts to change the motion of the fluid. In gravity concentration we are dealing with this force of resistance acting on the granular particles that are to be separated. Furthermore, the motion induced in the fluid by a particle will in turn affect the motion

Jan 1, 1943

By O. G. Kiel, G. W. Swift

The concept of "a continuous succession of steady-states", which has been applied successfully by Aromfsky and Jenkins to obtain a solution for the nonlinear partial differential equation describing the transient Darcy flow of gas through porous media, is demonstrated to be equally valid for transient non-Darcy flow. A mathematical model, which numerically solves the partial differential equation, is used to check the validity of the succession of steady-states solution. Comparison of sand-face pressure histories compelted by the two methods shows excellent agreement. The utility of the succession of steady-states solution in predicting performance of gas wells rests in the fact that no special computation equipment is required. The development of the succession of steady-states solution leads also to a practical method for determining and analyzing field test data. A method for taking gas-well test data under constant-rate conditions is presented. Experimental data obtained in the field by employing the constant-rate method are presented and analyzed in accordance with the succession of steady-states solution. Analysis of data in this fashion is demonstrated to give direct "in situ" information for reservoir permeability, porosity and turbulence or non-Darcy coefficient. INTRODUCTION The economics of gas production are dependent upon the transient behavior of flow within the reservoir. For production from a finite reservoir, the transient flow behavior can be subdivided into two parts. At first, the transient caused by the movement of the pressure "wave" into the reservoir is of importance. Later in the production history, the pressure-wave movement ceases and the second transient stage of material depletion becomes controlling. For reservoirs of relatively high permeability, it can be shown that the pressure wave moves into the reservoir and stabilizes quite rapidly. In the case of relatively impermeable reservoirs, quite the opposite is true. Although it is theoretically possible to compute the production capability of a well from the properties of the reservoir as determined by static tests and core analyses, more reliable information is obtained by conducting flow tests on the well and thereby obtaining some measure of "in situ" formation properties. For gas wells, there are two basic types of tests in existence: the flow-after-flow method,' and the isochronal method.' Both of these techniques are tailored to obtain data that can be analyzed in accordance with the empirical performance equation: In addition, the isochronal method makes provision for the sluggish nature of pressure-wave movement in "tight" formations by requiring pressure build-up between flows and by stipulating that data obtained on successive flows be analyzed at equal elapsed flow times. It can be demonstrated that either test is valid for reservoirs of high permeability. Further, since it has been pointed out that the pressure wave stabilizes rapidly for reservoirs of this type, tests of relatively short duration will give stabilized information on the performance of a well. Further decline of sand-face pressure and/or production rate may be determined by employing material-balance techniques. Cullender' points out that for relatively impermeable reservoirs the flow-after-flow method gives invalid results. (See Appendix C.) If the isochronal method of testing is used, there are two alternatives: (1) the tests must be conducted for a sufficient length of time to obtain stabilized information (which may require months to accomplish); or (2) some method for extrapolating the results of short-term isochronal tests must be employed. The first alternative is impracticable because of manpower, conservation and economic considerations. Recourse to the second alternative requires some assurance regarding the reliability of the extrapolation technique. Poettmann and SchilsonJ present an empirical method for predicting stabilized performance. The present investigation was originally initiated to determine the reliability of this technique. To do this, a mathematical model was developed to simulate the Darcy and non-Darcy flow of gas through porous media. The model consisted of a finite-difference approximation of the nonlinear partial differential equation which was solved on an IBM 7090 computer. Long-term production histories were simulated by the model and compared against predictions obtained from the Poettmann-Schilson method. As the work progressed, it became apparent that a straightforward predictive equation could be developed by utilizing the concept of a succession of steady-states. As a result, the emphasis of the work was redirected to exploit the advantages of the new method.

By Eugene Guccione

For at least a decade, the energy crisis was accurately predicted by a small number of industry people who were ignored until last year, when they suddenly found themselves accused for their "lack of planning" and "greed." With the worsening shortage of natural gas and oil, the current scramble is for alternate energy sources-which means: a big rush into coal and uranium mining. (Some big plans are also on the drawing boards regarding geothermal steam, oil shale, tar sands, and even solar energy. But developing such new industries from scratch would be difficult enough even in a healthy economic climate-which is not exactly what the country currently enjoys.)

Jan 8, 1974

By R. H. Hopkins, R. W. Kraft

X-ray and metallographic analysis reveal that the preferred cryslallograPhic relationships in direc-tionally solid~fied Pb-Sn eutectic specimens can be stated: interface growth direction, Experiments in which tin single-crystal seeds were used to nucleate the eutectic demonstrate that the normal lamellar structure observed at steady state can be forced to break down initially to a semide-generate structure when the crystallograPhic direction of the tin seed does not lie within the preferred eutectic interface plane. A normal structure eventually develops by preferred grain growth. X-ray topo-graphs and rocking curves substantiate that the perfection of eutectic samples increases as growth proceeds until steady-state conditions prevail. RECENT years have seen substantial progress made in the understanding of eutectic solidification through both intensive theoretical1'' and experimental investigations (see Ref. 7 for a review and extensive bibliography of both aspects). Several important observations concerning the nucleation and growth aspects of binary eutectic solidification have been brought to light. Briefly some of these include the nonrecipro-cal nucleation of one phase upon another,'j9 the tendency for a specific low-index direction of one or both phases of the eutectic to be aligned in the growth direction during unidirectional solidification,'0711 and the production of lamellar microstructures having a preferred interface plane between "11-13 phases. Questions quite naturally arise as to the mechanism by which preferred grain growth evolves during eutectic solidification and what relationships (if any) connect the initial nucleation of one phase upon another with the preferred growth directions and interface planes observed after a few centimeters of growth in many systems. This study was initiated in an attempt to answer these questions. An experiment was devised in which both the nucleation and growth steps in the crystallization of a binary eutectic, Pb-Sn, could be correlated with subsequently developed eutectic morphology and crystallography. This was accomplished by nucleating the eutectic upon a tin single crystal seed and then causing the eutectic to grow from the seed by directional freezing. The morphology of the structures produced in this manner was then monitored metallographically and the orientation relationships and substructural perfection determined by X-ray analysis. The information thus ob- tained was correlated to the growth history of the samples. EXPERIMENTAL DETAILS The eutectic of composition 38.1 wt pct Pb and 61.9 wt pct sn14 was prepared by accurately weighing lead and tin of 99.999+ (from ASARCO and Lytess Metals and Chemicals, respectively), melting in a clean Pyrex beaker under an argon blanket, and casting into the proper crucible for resolidification as described below. Tin seeds were grown by the method of ~halmers," saw-cut, oriented by the Laue method, and soldered to the pull rod of the Czochralski puller. All seeds were given a final electropolishing (to assure the removal of any deformed material from the cutting operation) and acetone degreasing immediately prior to the nucleation experiment in which they were to be used. Eutectic samples were unidirectionally solidified in a horizontal graphite boat1' or by pulling from the melt16 with tin (or graphite) seeds. A flowing argon atmosphere was employed in all experiments and growth rates and temperature gradients, constant for a given run, varied from 2 to 4 cm per hr and 8" to 15°C per cm over the course of all the experi-

Jan 1, 1969

By Joseph D. Weeks

The primary problems of civilization are material ones; their answers are writ in fire. When these problems in their higher aspects have pressed for solution, it has been out of the burning bush that the Divine voice has spoken, or in the cloud and smoke that the Divine finger has traced the rules by which these problems shall be solved. It is with the material problems, however, that we, as engineers, have to deal.

Jan 1, 1896

Prospecting methods used in Tennessee have gradually improved with the years, as required by depletion of the easily accessible and shallow deposits and the universal trend toward mechanization, and as necessitated by exploring deeper beds, often occurring under limestone and flinty overburden. In the early days it was a very simple matter to dig pits by hand, using a plentiful supply of local farm labor to expose relatively shallow deposits of "brown rock" under shallow clayey overburden that would stand up without timbering. Visual inspection of the exposed phosphate and expert judgment of the "grade" analysis, aided by a "biting" test to reveal presence of unwanted silica, furnished most of the information required. All this might be helped by a few samples sent to the local chemist† who supplemented his income by judicious trading or tanning a few bear skins. The extra curricula activities did not affect the accuracy of the analysis which hold up even under present day standards. Some shot and core drilling was done in Hickman County, mostly for the limestone-like blue Phosphate deposits. The next step was the use of a 4-in. posthole auger, hand operated as described by Guenther, followed by a completely mechanized rig, as described by Pickard. Both these methods are practically adapted to the prospecting of the relatively soft brown rock deposits at moderate depths of clay overburden. For prospecting in areas of deeper overburden, such as are often found in Hickman County, up to 150 or even 200-ft depths, a modified core-drilling method is described by Guenther. Johnston describes a special diamond-drilling technique, developed by TVA, to penetrate flint horizons, which was adopted by the International Minerals in chemical corporation to prospect in Hickman County where deposits had previously been prospected at considerable expense and with difficulty, by small, temporary, hand-dug shafts.

Jan 1, 1948

Prospecting methods used in Tennessee have gradually improved with the years, as required by depletion of the easily accessible and shallow deposits and the universal trend toward mechanization, and as necessitated by exploring deeper beds, often occurring under limestone and flinty overburden. In the early days it was a very simple matter to dig pits by hand, using a plentiful supply of local farm labor to expose relatively shallow deposits of "brown rock" under shallow clayey overburden that would stand up without timbering. Visual inspection of the exposed phosphate and expert judgment of the "grade" analysis, aided by a "biting" test to reveal presence of unwanted silica, furnished most of the information required. All this might be helped by a few samples sent to the local chemist† who supplemented his income by judicious trading or tanning a few bear skins. The extra curricula activities did not affect the accuracy of the analysis which hold up even under present day standards. Some shot and core drilling was done in Hickman County, mostly for the limestone-like blue Phosphate deposits. The next step was the use of a 4-in. posthole auger, hand operated as described by Guenther, followed by a completely mechanized rig, as described by Pickard. Both these methods are practically adapted to the prospecting of the relatively soft brown rock deposits at moderate depths of clay overburden. For prospecting in areas of deeper overburden, such as are often found in Hickman County, up to 150 or even 200-ft depths, a modified core-drilling method is described by Guenther. Johnston describes a special diamond-drilling technique, developed by TVA, to penetrate flint horizons, which was adopted by the International Minerals in chemical corporation to prospect in Hickman County where deposits had previously been prospected at considerable expense and with difficulty, by small, temporary, hand-dug shafts.

Jan 1, 1948

By Gilbert Doan

AN extensive program of investigation is being carried out at Lehigh University in the study of arcs and arc welds of high-purity iron1, spon-sored by the Engineering Foundation. The part of that program reported in the present paper deals with welds made of high-purity iron in an argon atmosphere and for comparison with them welds made of the same iron in ordinary air. Welds of commercial steel also were made in argon and in air. The primary purpose of the study is to discover the basic physical constants of iron welds when not contaminated either by impurities in the iron or by the action of oxygen and nitrogen of the air during welding. Upon these constants can be founded such future studies as will determine what effects the various impurities and alloy elements present in steel have upon its welding characteristics, and what influence is exerted by the action of oxygen and nitrogen. The welding of steel involves such a multitude of variables, both of composition and of procedure, that development in the fabrication of this most important metal has necessarily been slow, wasteful, and in many instances discouraging. In the present investigation, the simplest possible condition has been selected; namely, iron practically free from contamination and a nonparticipating atmosphere, the inert gas argon. This simplification reduces the number of variables to a point where more rigid control of the system is possible. Although this study is significant for the contributions it makes to the science of steel fabrication, yet it is hoped that it will not be without value also in increasing knowledge of the nature and behavior of iron and steel in general. From the standpoint of open-hearth practice, and to

Jan 1, 1936

By Glenn C. Waterman

THE diamond drill is a very important tool in exploration and development testing and its use is increasing. In almost all cases results of diamond drilling are analyzed on the basis of grade and tons. A proper evaluation of core and sludge assays is important if drilling results are to be acceptable as a basis for geologic and engineering appraisal. The relatively wide variation in assay averages as calculated by various well-known combining methods indicates that the engineering choice of a method may affect the outcome of the drilling in terms of ore and waste. The problem of combining assay results from core and sludge samples has been discussed many times in conference and in the literature.'-' Most writers agree that the field of disagreement in methods is large and that the engineer on the job must consider features unique to his drilling, pick one of several combining methods, and depart from the rules when abnormal results come in. All the discussion to date can be summed up by the admission that as yet there is no fairly simple, generally acceptable combining method that is practicable over a wide range of drilling conditions, ground conditions, and ore occurrence. The combining problem is important in evaluating drilling results at Chuquicamata. Recently a reappraisal has been made of recovery variables and their effect on assays, with the result that a new combining method is offered which fits average drilling conditions and is mathematically reasonable. It is simple in application, fundamentally correct, and an improvement over most combining methods. At Chuquicamata diamond drillholes are used to outline the grade and position of blocks of normal and marginal grade oxide, mixed, and sulphide ore. Most holes penetrate all classes of material (and waste), and it is important for mining programs as well as ore reserves to know almost precisely the soluble and insoluble copper content of mineralized ground. At present three classes of ore are mined and treated differently. For an orderly sequence of mining operations which can provide regular daily tonnages of all three ore types and keep grade at certain levels with minimum variation, ore type and its grade must be predicted. Diamond drilling plus geologic mapping and bench sampling are tools for prediction. And drilling data are largely used to calculate grade of material more than a few meters away from bench faces. The orebody at Chuquicamata" is criss-crossed by millions of barren or mineralized weak to fairly strong slips and fault fissures. Mineralization is diverse and encompasses many quartz and oxide or sulphide-bearing copper veins, as well as seams and disseminated grains. Copper occurs in oxide or sulphide minerals or mixtures of these two mineral types. Rock conditions vary from intensely seri-citized (soft and porous) through clay-altered ground to almost fresh granodiorite. The result is an orebody which offers many obstacles to good and consistent core recovery in diamond drilling. Recovery varies considerably in the several alteration zones, the various types of oxide and sulphide ores, and the position and inclination of the drillhole within the complex fracture pattern. As core recovery drops sludge samples must be used with core samples to calculate grade. Many years of drilling at Chuquicamata indicate that in good grade oxide zones and in the sulphide areas core recovery is good and the ground uniformly mineralized. Moderate loss of core, therefore, does not markedly affect grade calculations based on core assays. An early core-sludge combining method used core assays at face value as indicating grade down to 50 pct core recovery, but below this recovery percentage sludge samples were used and weighted according to the standard Longyear chart. This method apparently did not introduce serious errors, but it abruptly used sludge assays with high weighting factors representing 100 pct return irrespective of actual percentage of sludge recovered. Recent drilling activities have been directed toward outlining the marginal ore areas. The non-uniform mineralization and generally poorer core recovery in such ground indicated that a more exact core-sludge combining method was required to equate wide differences between core and sludge assays and recovery. In fringe ore areas at Chuquicamata core recovery averages about 50 pct, from a minimum of 10 to 15 pct to a maximum of 100 pct. Sludge recovery is likewise variable and averages perhaps 80 pct even though holes are cemented as water return falls off. In a homogeneously mineralized area cut by many slips and faults, with hard and soft ribs, loss of core is loss of ground which has a grade similar to that of core recovered, and core assays approximate true grade. In this case sludge samples need not be used. However, it would be unusual to know beforehand that an area is uniformly mineralized, and in fact this condition is probably uncommon. Generally the distribution of valuable minerals in the ground does not exactly compare with their recoverability in core. Thus, in the usual case, loss of core decreases the

Jan 1, 1956

By Fred Bond

THERE is acute need for a method that will measure the size distribution of finely di-vided materials, particularly when the par-ticle sizes are smaller than the openings of the finest screen cloth regularly available for testing. Several methods and types of apparatus are in common use, but none are entirely satisfactory for all purposes. The commonest methods are microscopic grain counts, elutriation by liquids or air, and sedimentation. Valuable results have been secured by air elutriating devices, typified by the Haultain Infra-Sizer and the Pearson Air Analyzer. These are especially useful in obtaining sized fractions that can be examined and analyzed separately. They are particularly advantageous because the sizes of the sam-ples produced are adequate for a consider-able amount of subsequent manipulation and testing. The sedimentation methods, such as the Wagner and Klein turbidimeters, and the sedimentation balance, do not deliver sized fractions, but they do provide a means for reasonably rapid comparative determina-tions of fineness and surface area, which are important in many industries. The sedimentation balance consists essen-tially of a balance pan suspended in a liquid that contains falling particles. These are weighed as they settle onto the pan, and the time rate of settling is determined. The size distribution is computed from the set-tling rate. The balance appears to be in-herently more accurate than any of the other methods, and it has served a useful purpose in the study of numerous problems, but there have been limitations which have re-stricted its scope of application. Because of the essential simplicity of the method, it was felt that intensive investiga-tion might lead to modifications that would make it a valuable tool for the operators in industries that require precise information regarding the results secured from grinding equipment. A large number of size-distribu-tion determinations below 200 mesh were required in connection with a particular research problem in fine grinding. The sedimentation balance was used, in this investigation, and a technique was gradually developed that ultimately gave good results. A serious difficulty appeared, early in the work. It was discovered that less material always settled on the sedimentation pan and more on the bottom of the containing jar than could he accounted for by calculation, and also that the material that settled to the bottom of the jar outside the edges of the pan was considerably finer than that on the pan. This segregation was so great that the dis-tribution obtained for the finer sizes was obviously very much in error; material ground to about the degree of comminution of cement might have only 60 per cent of the calculated weight actually settling on the pan, and the error increased with the fine-

Jan 1, 1939

By H. T. Byck

The plastering properties of six representative California drilling muds were studied over a temperature range of 70 to 175 F. at several mud weights, using a high-pressure circulating filter press with full size consolidated cores. In all tests, with untreated as well as with chemically treated muds, the filtration rates at elevated temperature were higher than at low temperatures and in nearly every case this increased filtration rate was notably larger than could be attributed alone to the decreased viscosity of water—the flowing medium—at elevated temperatures. It is concluded that no existing method will permit even an approximate determination of the filtration rate at high temperature from data at room temperature. It is necessary to measure filtration at the temperature actually anticipated in the well, or to make a sufficient number of tests at various lower temperatures so that a small extrapolation of these data to the anticipated well temperature may be applied. Such tests should be carried out on the mud as actually used in the well. The viscosity of each of the muds was determined over the same temperature range. While no relationship was observed between mud viscosity and plastering properties, it was found that chemical treatment of the muds for viscosity reduction shifted the temperature of minimum viscosity to appreciably higher values than for untreated muds. Importance of Plastering Properties A survey of the literature on rotary drilling muds clearly shows the growing realization of the importance of plastering properties,'-5 not only from the point of view of the successful completion of the mechanical operation of drilling the well but also from the point of view of minimum impairment of the natural flow possibilities of a given well. Poor plastering properties with attendant high filtration rate (large water loss to the formation) and thick mud sheath, lead to stuck drill

Jan 1, 1940

By H. T. Byck

The plastering properties of six representative California drilling muds were studied over a temperature range of 70 to 175 F. at several mud weights, using a high-pressure circulating filter press with full size consolidated cores. In all tests, with untreated as well as with chemically treated muds, the filtration rates at elevated temperature were higher than at low temperatures and in nearly every case this increased filtration rate was notably larger than could be attributed alone to the decreased viscosity of water—the flowing medium—at elevated temperatures. It is concluded that no existing method will permit even an approximate determination of the filtration rate at high temperature from data at room temperature. It is necessary to measure filtration at the temperature actually anticipated in the well, or to make a sufficient number of tests at various lower temperatures so that a small extrapolation of these data to the anticipated well temperature may be applied. Such tests should be carried out on the mud as actually used in the well. The viscosity of each of the muds was determined over the same temperature range. While no relationship was observed between mud viscosity and plastering properties, it was found that chemical treatment of the muds for viscosity reduction shifted the temperature of minimum viscosity to appreciably higher values than for untreated muds. Importance of Plastering Properties A survey of the literature on rotary drilling muds clearly shows the growing realization of the importance of plastering properties,'-5 not only from the point of view of the successful completion of the mechanical operation of drilling the well but also from the point of view of minimum impairment of the natural flow possibilities of a given well. Poor plastering properties with attendant high filtration rate (large water loss to the formation) and thick mud sheath, lead to stuck drill

Jan 1, 1940

By Paul Giesecke

Since most modern metallurgical plants are operated continuously and on a large scale, successful operation at maximum efficiency demands that an accurate knowledge of the performance at each stage of the process be available at all times. Quantitative analyses provide the most practical process guides, and it is essential to have analytical procedures that combine accuracy and speed. In continuous plant operations, large losses may occur if the time interval between the development of trouble at any stage and its recognition and correction is great. Many metallurgical plants are using rapid colorimetric and spectrochemical methods of analyses for control purposes. So-called "color coppers" may be cited as an example of the colorimetric methods, in contrast with- the routine use of the ultraviolet spectrograph for the analysis of steels.42 By means of this more refined spectrochemical procedure, a complete quantitative analysis of the molten metal is obtained every few minutes. During the past two years the Physics Division and the Ore Dressing Laboratory of the American Cyanamid Company's Stamford Research Laboratories have collaborated in a study of the use of spectrochemical methods for the analysis of various metallurgical products. New methods have been developed, which have proved of practical value in plant operation. The following pages give a general review of the principles of spectrochemical methods and also the details of several specific analyses. Principles of Spectrochemical Analysis In general, it can be said that a visible light spectrochemical analysis can be performed for any ion or molecule that is naturally colored, or that can be made to react with another to produce a colored salt or complex. Whereas transmission measurements in the ultraviolet and infrared portions of the spectrum are most useful for the analysis of organic molecules, * visible light measurements are of particular value for metal salts. Such elements as copper, manganese, cobalt, nickel, iron, molybdenum, vanadium, chromium, phosphorus, mercury, zinc, lead, and a great many others, can now be determined with a high degree of sensitivity, accuracy and dispatch. From the simplest of qualitative determinations, color analyses have been improved to such an extent that, at the present time, through the use of recording spectrophotometers, hundreds of accurate quantitative analyses can be performed by a single analyst during an 8-hr. day after the standardization curves have been established for the ions to be determined.

Jan 1, 1947

By Paul Giesecke

Since most modern metallurgical plants are operated continuously and on a large scale, successful operation at maximum efficiency demands that an accurate knowledge of the performance at each stage of the process be available at all times. Quantitative analyses provide the most practical process guides, and it is essential to have analytical procedures that combine accuracy and speed. In continuous plant operations, large losses may occur if the time interval between the development of trouble at any stage and its recognition and correction is great. Many metallurgical plants are using rapid colorimetric and spectrochemical methods of analyses for control purposes. So-called "color coppers" may be cited as an example of the colorimetric methods, in contrast with- the routine use of the ultraviolet spectrograph for the analysis of steels.42 By means of this more refined spectrochemical procedure, a complete quantitative analysis of the molten metal is obtained every few minutes. During the past two years the Physics Division and the Ore Dressing Laboratory of the American Cyanamid Company's Stamford Research Laboratories have collaborated in a study of the use of spectrochemical methods for the analysis of various metallurgical products. New methods have been developed, which have proved of practical value in plant operation. The following pages give a general review of the principles of spectrochemical methods and also the details of several specific analyses. Principles of Spectrochemical Analysis In general, it can be said that a visible light spectrochemical analysis can be performed for any ion or molecule that is naturally colored, or that can be made to react with another to produce a colored salt or complex. Whereas transmission measurements in the ultraviolet and infrared portions of the spectrum are most useful for the analysis of organic molecules, * visible light measurements are of particular value for metal salts. Such elements as copper, manganese, cobalt, nickel, iron, molybdenum, vanadium, chromium, phosphorus, mercury, zinc, lead, and a great many others, can now be determined with a high degree of sensitivity, accuracy and dispatch. From the simplest of qualitative determinations, color analyses have been improved to such an extent that, at the present time, through the use of recording spectrophotometers, hundreds of accurate quantitative analyses can be performed by a single analyst during an 8-hr. day after the standardization curves have been established for the ions to be determined.

Jan 1, 1947

By E. H. Jr. Crabtree

THE productive area of asphalt-bearing sandstone in Missouri is near the Missouri-Kansas state line near Nevada, the county seat of Vernon County about 100 miles south of Kansas City. While produc-tion thus far has been confined to Vernon and Barton counties, there are known deposits in adjacent counties. The area is served by four rail-roads: the Missouri Pacific, the Kansas City Southern, the Missouri-Kansas & Texas, and the St. Louis & San Francisco. The plant of the Reliance Rock Asphalt Corporation is in Vernon County, about 5 miles west of Nevada, at Ellis, a flag station on the Missouri, Kansas & Texas Railroad. A siding has been built to the plant so that the finished product can be loaded directly into railroad cars. The property consists of a lease of 240 acres in one block. All portions of the property not required for quarrying or processing the asphalt-bearing sandstone are used for farming by the fee owner. The entire tract is very flat so that there are no transportation difficulties from quarry to plant.

Jan 1, 1935

By Earl L. H. Sackett

This laboratory centrifuge is unique in its low cost and ease of construction, its particular adaptability to problems encountered in an ore dressing laboratory and its simplicity of operation. It will treat a sample of the size ordinarily used in a laboratory flotation test. The centrifuge was designed at the Baroid Sales Division of the National Lead Co., Malvern, Ark., and built in a local machine shop to serve as a laboratory machine which would produce results comparable with those obtained in the large scale centrifugal deslimers in use in our Magnet Cove mill. The apparatus has served quite well in this capacity and has also proved effective as a deslimer on a variety of ore dressing problems. The cost of making this machine was relatively low and it is simple to operate. It is strictly a batch machine, but when operated under proper conditions, gives results which agree quite closely with large continuous-flow machines of the same type. Effective separation of minus 5 and 10 micron material is made in an undispersed pulp in a short time.

Jan 4, 1950

By L. R. Jackson, W. T. Lankford, K. F. Smith

COMMERCIAL steel sheet is prepared by a combination of hot and cold rolling and annealing. This treatment usually results in more or less pronounced anisotropy. The [ ] anisotropy may manifest itself both as preferred orientation and in the manner in which impurities, segregations, and the like, are aligned in the sheet. The type of preferred orientation and the organization of impurities or segregations may affect the elastic moduli, the yield strength, the tensile strength, and almost always the amount of ductility in different directions. In any case, the most important directions concerned in the anisotropy are along the rolling direction, along the width direction, and along the thickness direction. Considerable data exist on the anisotropy of sheet steel as demonstrated by conventional tensile tests; however, few attempts have been made to measure the constants of plastic anisotropy and use them to describe the flow of anisotropic sheet under combined stresses. [ ] In this paper, evidence is presented indicating that plastic flow in anisotropic sheet can be described by the shear-strain energy flow theory provided that the anisotropy is properly taken into account. MATERIALS USED IN THE INVESTIGATION Table I lists the sheet materials used in this investigation and describes the condition in which materials were tested. DESCRIPTION OF TESTS AND TEST METHODS Two types of tests were run-tensile tests and hydraulic-bulge tests. Characteristic parameters of anisotropy were determined from the tension tests by methods which will be described later. In all cases, the tensile test pieces were cut from the same quarter line and adjacent to the bulge test pieces in the sheet in order to minimize

Jan 1, 1948