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By Dean W. Lynch

Arizona: The San Xavier Indian Reservation mine is located approximately 2 ½ miles northwest of Asarco's Mission Mine southwest of Tucson. The company plans to produce oxide and copper-bearing siliceous ore at this operation, construction of which is scheduled for completion in 12 months. Asarco also plans a copper leaching and iron precipitation plant at its mine. The plant will leach 4000 tpd of oxide ore using sulfuric acid produced at the company's acid plant now under construction at Hayden. Copper precipitates will go to the smelter at Hayden. A drilling program at the Sacaton copper prospect in Pinal County, has disclosed two porphyry copper deposits. One deposit, mineable by surface mining, has approximately 17 million tons of material averaging 0.80% Cu. A deeper deposit suitable for under- ground mining has approximately 12 million tons averaging 1.5% Cu. Although Asarco intends to place this property in production, no startup date has been determined.

Jan 1, 1970

By W. Mostowitsch, H. O. Hofman

In a previous paper,' The Behavior of Calcium Sulphate at Elevated Temperatures with Some Fluxes, we published the results of our investigation into the behavior of calcium sulphate in air; that is, under oxidizing conditions. The results as a whole hold good for a neutral atmosphere, or one which has no chemical effect upon calcium sulphate. The present paper deals with the behavior of calcium sulphate under reducing conditions, the reducing-agents employed being carbon monoxide and carbon, and the changes the calcium sulphide formed undergoes when it is subjected to an oxidizing-roast. Technical literature deals very sparingly with the subject. The information furnished by the recent leading chemical manuals is general. Thus Dammer,2 Missan,3 and Abegg4 quote Berthier as having reduced, in 1823, calcium sulphate with carbon, and Stammer as having done the same in 1851

Jan 1, 1911

By R. C. Rumble

To /neet the need for a subsurface flowmeter capable of measuring low rates of flow, a new type flowmeter has been built and tested in the field. This instrument is self-contairzed, can be run on a wire measuritzg line, and may be run through 2-in tubing. It consists of a rotameter flow-measuring assembly used in conjuncfion with a conventional subsurface instrument clock and chart. Integral with the tool is an inflatable packer which, by effecting a seal between casing and tool, diverts all fluid through the metering assembly. Packers of different size adapt the tool to different sizes of casing or liner. The flowmeter is capable of measuring rates of flow as low as 4 BID. The flowmeter has been run experimentally in seven wells. It has yielded satisfactory resrrlts in five of the wells, and in the other two it failed to operate because of loose sand in the hole. INTRODUCTION One of the oldest problems facing the producing branch of the petroleum industry is the location of depths of entry of fluid into a wellbore and the determination of the amount of fluid entering at each depth. This problem is often encountered in oil and gas wells completed in single producing horizons as well as in multiple pays; it is a common problem in oil wells which produce excessive volumes of gas. Several subsurface instruments designed to detect and meter flow in the producing interval of wells have been described in the literature.1,2,3,4 Most of these, however, were apparently intended for use in wells producing at relatively high rates of flow, and consequently lack sensitivity to low flow rates. Because of this and of other possible disadvantages inherent in these instruments, development of the subsurface flowmeter described in this report was undertaken. DESIGN OF FLOWME'I'ER Design Requirements In considering the requirements for a flowmeter that would not be subject to the limitations of devices existing at the time work was started, attention was first given to the size of the tool. Such an instrument should be of sufficiently small diameter that it could be lowered readily in 2-in tubing in a producing well. The flowmeter should contain a recording unit so that it might be run on a wire measuring line with conventional reeling equipment. It should not be too long to be accommodated by a portable lubricator of the type used for running conventional subsurface instruments. The metering mechanism of the flowmeter should not be affected appreciably by the viscosity or density of the flowing fluid. Such an instrument should record flow rates in the range from less than 10 B/D to over 100 B/D. To achieve this, a packer should he provided to divert through the instrument all fluid flow in the wellbore. This packer should be of such nature that in the event of excessive flow the fluid would bypass the instrument instead of forcing it up the wellhore. General Description A flowmeter incorporating most of the desired features outlined above was developed and built. The instrument is an elongated tubular device terminated on

Jan 1, 1956

By D. W. Mitchell

INE operators have a choice of several classi- fications of mechanical loaders. Within each classification there are many types and makes available. Table I lists loaders on which manufacturing data as to operating characteristics are available. This paper discusses the conditions met in a mine as they affect these characteristics. It is assumed that management will provide satisfactory engineering, supervision, power, maintenance, loader service within a concentration of workings, and a balanced working cycle served by balanced production equipment. These are factors which affect the optimum operational efficiency of a loader. The conditions which determine loader choice are: Height of Vein—The main limitation to the use of a loading machine is the height to which the vein is mined; i.e. a loader cannot be higher than the place in which it is to work unless rock is taken. Since there are several low vein loaders being developed and successfully applied, this does not appear to be a requisite of an efficient mining operation. The maximum useable height of a loader should be equal to the working seam thickness less a working clearance for travel and operation. A—Working seam thickness = B—Artificial roof support thickness = C—Safe headroom below support = (generally about 6 in.) D—Height of roadway = E—Total of B + C f D =_______________________ A—E = maximum loader height F—Distance from top of roadway to bottom of roof support = G—-Height of loader's coal or ore line (see Table I) = H—Difference between F and G = Size of largest broken particle + a safety factor of 2 to 3 in. H is a loadability factor and is important because the clearance over the top of the conveyor chain to the roof or roof support must be greater than the largest broken particle or else the particle and/or the conveyor chain may be broken. From this standpoint it might be desirable to use a lower height machine even though it may have a smaller capacity, though this is warranted only when increased lump realization offsets lower man-day and machine pro- duction rates. Ivan Given has stated, "Loading should not be handicapped by securing lump only to grind it in the breaker." Width of Working Place—The width of a working place is the greatest width a place may be safely driven. The working place includes not only the face but the roads the loader must tram when mucking out more than one face. The width is limited by the system of placing props with sufficient room between them for the machine runner (about 2 ft). Maximum width of place in which the loader will operate at maximum efficiency is determined by the type of mounting. With track-mounted loaders, maximum width of place is determined by maximum angular swing of the loading head and proximity of track to the face. The use of double track leads to added expense and operational complexities. Several mines that have used double-track systems have found that a substantial saving is made by the use of machines that load out wider places. Trackless loaders may work in rooms of any maximum width. Minimum width of place in which a loader will operate is determined by width of the loader plus a safe movement area for the operator. Often a barodynamic study of the mine will show that either an increase in room width and/or a change in the system of propping may be made by using roof bolting, full or part-width room timbers, removable aluminum I-beams at the face, etc. Increasing the width of a working place will, in general, increase loader operating efficiency by providing more material per fall and by decreasing the preparation and moving time per ton. A change in the system of propping that would increase the minimum width might permit the use of a higher capacity loader with safer working conditions. Proper face tirnbering is necessary to insure safety from roof falls and because the speed of preparation and loading generally increases since the men work with greater assurance and there is less chance of kicking out posts. Maximum Room Length—With the exception of the scraper and the duckbill, the limit to room

Jan 1, 1952

By A. S. Appleton, M. B. Bever, G. E. Dieter

A gold-silver alloy was deformed by explosive loading at shock pressures up to 510 kbars. The stored energy and hardness increased over the whole range of pressures; the largest rates of increase were observed between 120 and 150 kbars. In this range, markings rkavacteristic of defornation twins first appeared; higher pressures produced markings in all grains. These effects are compared with those of conventional deformation processes and are discussed in relation to probable structural changes. In recent years, increasing efforts have been devoted to the investigation of the effects produced in metals by the passage of high-intensity shock waves of explosive origin. By properly utilizing the energy released by the detonation of a high explosive, it is possible to generate pressure pulses of the order of 500 kbars and higher. (One kbar equals l0 9 dynes per sq cm or approximately 1000 atm.) The passage of a shock wave through a metal occurs at pressures which are very much greater than the yield strength. As the shock front passes a point in the metal, the pressure rises almost instantaneously, and continues to act at the point for a few microseconds. Thus, metals subjected to explosive shock loading experience a nearly instantaneous increase in pressure, and a subsequent release of pressure, which is almost as rapid. Under these conditions mechanical twinning and shear transformations occur readily. smith1 has investigated the metallurgical changes in copper and iron resulting from exposure to explosive shock waves. He found an appreciable increase in hardness in both metals. In copper, a hardness greater than that resulting from 95 pct reduction in thickness by rolling was obtained, yet in the explosive deformation, the thickness of the specimen decreased only a few percent. After explosive loading, the micro-structure of copper showed markings characteristic of mechanical twins. The amount of stored energy resulting from explosive loading is of interest. Measurements of the stored energy of cold work as a function of strain, temperature, strain rate, and composition have been made with gold-silyer alloys deforyed by rolling, orthogonal cutting,3 drilling,4 filing, wire drawing, and torsion. The investigation reported here was also carried out with a gold-silver alloy and its results can be compared with those for the deformation of this alloy by more conventional methods. EXPERIMENTAL PROCEDURES An alloy containing 82.6 wt pct Au and 17.4 pct Ag was purchased in several batches from Handy and Harman Co., New York, as annealed rod 1/4 in. dim. The rod was cold-rolled to a sheet approximately

Jan 1, 1962

By W. A. Hoyer, G. A. Lock

Laboratory and field tests have shown that it is feasible to log for copper in a qualitative way using the techniques of neutron activation analysis. Laboratory tests showed that the 0.51 and 1.04 mev gamma rays of 62Cu and 66Cu, respectively, could be diagnostic. However, in the core holes, the detection of copper was limited to 0.3% concentration because of interferences from the 18Si and Al gamma rays. Both stationary and continuous logs were made, but only the stationary data yielded a recognizable copper response. This response consists of a combination of two effects-the direct response from copper at 0.51 mev and an increase in low energy gamma ray absorption due to mineralization. Both low energy chemical (PuBe) and high energy accelerator neutron sources were used for the laboratory and field tests, while the same 2 X 5 in. Nal scintillation detector served for all the tests. Potential improvements in copper detection might be possible with solid state gamma-ray detectors which have better gamma ray resolution but much less detection efficiency. This type of activation logging requires complex equipment and trained personnel to conduct field operations and may find application where coring is difficult or prohibitive.

Jan 1, 1973

By Charles Kirchhoff

For twenty years it has been my work to watch and record progress in both the technical and the commercial branches of mining engineering in the wide sense in which it is represented by our Institute. While you who have been actively engaged in our profession have made history, a few of us have attempted to be the historians and have been kept keenly on the qui vive to follow the developments of so broad a field. One so employed may be pardoned if he ask you to pause for the unusual purpose of looking backward, that you may measure what you and others have done, and that the younger men may gather inspiration from the work accomplished by their elders and their predecessors. It is not so long since that the commercial management dominated our industries. Bred in the school of science, which seeks its reward in establishing the truth, our engineers were sometimes indifferent to trade conditions and requirements. Much of that feeling has disappeared, and the engineer recognizes that it is his mission to apply the achievements of science to a useful commercial end. On the other hand, business men now understand that the utilization of our natural resources and the production of articles for consumption is impossible without the intervention of the engineer. They must co-operate, unless, indeed, the two functions are combined in one man —a rare but powerful combination. Now the final measure of success of both is the cost sheet on the one hand and the expansion of markets on the other, so closely interwoven, so mutually interdependent. There is one cardinal feature, however, which characterizes the engineer's work—namely, the permanence of his achievements. Every improvement, particularly when it has been recorded in such lasting form as a paper in the Transactions of our societies—

Jan 1, 1900

By Nick A. Hasenack, Heinz Kister, Rolf B. Vogel, Kees H. van Toor

A full survey of the laboratory and blast furnace tests carried out on two types of acid pellets is given. From the lab tests it appears that type B has a better low temperature disintegration index and a lower reducibility index than type A. The chemical composition and swelling indexes do not differ for both types. From the blast furnace test periods, carried out with a charge of 45% of pellets and 45% of sinter, it follows that both types of pellets lead to the same pig-iron production, blast furnace permeability, and blast furnace dust production. It also can be concluded that type B pellets cause a significantly higher coke consumption.

Jan 1, 1977

At the eastern end of the Mesabi Range, 70 miles due north of Duluth, is the vast plant of Erie Mining Co. Operated by Pickands Mather G Co. for the mine's four owners-Bethlehem Steel, Youngstown Sheet and Tube, Inter- lake Iron, and Steel Co. of Canada-Erie Mining Co, has earned just fame as a pioneer and a leader in the mining, beneficiation, and agglomeration of the lean iron ores of the Lake Superior district. Here is the story of Erie and the integrated operations that have made it such an outstanding member of America's iron ore industry.

Jan 5, 1963

Contents A - Metal Mining B - Minerals Beneficiation F - Coal H - Industrial Minerals I - Mining Geology L - Geophysics

Jan 11, 1953

By H. D. Outmans

The mechanics of filtration are described by a theoretical-empirical nonlinear diffusion equation which, under certain circumstances, may,be linearized and then solved explicitly. For filtration under static conditions linearization leads to a boundary value problem analogous to a heat flow problem with a known explicit solution. The corresponding solution for static filtration is compared with published experimental data. Under dynamic conditions filtration takes place in three successive stages. During each of these the rate of filtration and/or the thickness of the filter cake are different functions of the filtration time. The proposed mechanism explains the observed high resistance of dynamically deposited filter cakes against erosion and also the connection between filtration rate and viscosity of the drilling fluid. Several of the quantities governing dynamic filtration have no counterpart in the static filtration mechanism. The static filtration rate is, therefore, not a reliable measure for the dynamic rate and vice versa. INTRODUCTION Filtration under simulated borehole conditions, i.e.. either from a static suspension or from a suspension flowing parallel to the filter cake (dynamic filtration), has been the subject of several laboratory studies.1-7 This experimental and theoretical work showed that many aspects of the filtration mechanism cannot be explained by an elementary filtration theory based on the assumption that the filter cake is incompressible. For a more satisfactory theory compressibility should be taken into account. This has been done. at least to some extent, in the filtration theory developed for the chemical industry. Surveying the literature (see Ref. 8 for a bibliography) it becomes apparent that, although several properties of filter cakes deposited from many different suspensions have been measured, including compressibility, the filtration equations are essentially empirical in nature. No attempt has been made, for instance, to develop filtration theory along the lines of consolidation theory.12 This theory, upon which a highly successful development in soil mechanics rests, would appear to be an excellent starting point for a filtration theory since the compressibility concept is an essential part of it. As we will use this theory in the following development it is well to state the four assumptions on which it is based: 1. The fluid flow through a compressible porous medium is governed by Darcy's law. 2. The rate of change in fluid content of an element of the porous medium is proportional to the rate of change of solid pressure between the particles. 3. The solid particles are incompressible within the range of pressures considered. 4. The total pressure on a surface normal to the line of flow is equal to the sum of the fluid pressure and the pressure between the particles (solid pressure) at that surface. To calculate the rate of filtration and other quantities of interest it is necessary to know the filter cake compressibility and the permeability as a function of the solid pressure. It has not been possible to calculate these functions from theoretical considerations and they will therefore be introduced in this paper as empirical expressions. Both are determined in a compression cell where the cake is subjected to a mechanical load. Permeability and compressibility are measured after the solid pressure has stabilized, i.e., after the excess fluid pressure has been dissipated and the uniform pressure is transmitted entirely by the solids. The permeability and compressibility thus determined are not the same as during filtration in the borehole, under either static or dynamic conditions, because then, due to frictional drag, the solid pressure and hence also the permeability and compressibility vary along a line normal to the direction of the mean flow and can only be defined locally. DERIVATION OF THE FILTRATION EQUATION FOR COMPRESSIBLE FILTER CAKES As the filter cake in the borehole is thin compared to the radius of the hole the filtration may be considered as linear. Taking the x-axis normal to the wall, with its origin at the formation, we have, according to Darcy's law,

By G. F. Loughlin

The subject of this lecture might well have been assigned to an economist or banker rather than to a geologist, but, as it was deliberately assigned to me, it is to be treated from a geologist's viewpoint. The term precious metals ordinarily includes the platinum group as well as gold and silver. Platinum, like silver, has had a great decline in price during the last few years, but has not been a medium of exchange and therefore has aroused comparatively little comment. Its relation to price level is like that of commodities in general, and will be dismissed without further comment. Of the two precious metals used as mediums of exchange gold, because of its adoption as the basis of most monetary systems and because of its threatened shortage in the near future; has been a subject of general concern to governments, financiers, and economists; silver, on the other hand, which has flooded the market of late has brought forth cries for help, direct or indirect, from producers and to a less extent from the largest users, especially China, whose purchasing power has been greatly curtailed, but it fails to arouse the interest that gold does. Many predictions have been made by economists, bankers, and others regarding future supply of gold and its effect on prices but the differences among these predictions are about as many as the number of prophets. Since gold is the standard by which the value of commodities as a whole is to be measured, it would seem that the greater the ratio of gold supply to commodities the higher the price level and vice

Jan 1, 1932

By E. N. Skinner, Arthur Philliops

During the course of an experimental program concerned with the hydrogen embrittlement of copper containing oxygen in concentrations within the solubility limits it became necessary to make a critical appraisal of the literature dealing with the solubility relationships of oxygen and solid copper. The latest determinations, and perhaps the only data obtained on "spectroscopically" pure copper, are those of Rhines and Mathewson' who reported that the solid solubility increases from 0.007 per cent oxygen at 600°C. to about 0.01; per cent at 1500ºC. Hanson, Marryat and Ford2 had previously placed the solubility limit at less than 0.009 per cent oxygen at 1000ºC. and Allen and Street3 had suggested, on the basis of an unpublished research by T. Hemitt, not over 0.005 per cent oxygen at 500°C. In the introductory stages of the investigation indirect evidence accumulated to suggest that the solubility limits were significantly lower than those previously reported. For this reason it was deemed essential to clarify this point before proceeding with a program intended to establish a quantitative relationship between hydrogen embrittlement and oxygen concentrations positively known to be within the solid solution range. Furthermore, the increasing production and the highly selective applications of the commercial "oxygen-free" coppers inevitably direct attention to the practical necessity for exact knowledge regarding the effects of mini-tie concentrations of the elements ordinarily found in the high-purity coppers now available. Of these elements oxygen occupies a unique position, not only by virtue of its specific effects on copper but more particularly in view of its important reactive tendencies toward the other impurities with which it is associated. Rhines and Mathewson considered several methods for measuring the solubility of oxygen and finally adopted the simple plan of saturating the specimens, obtained from redeposited cathode copper, by heating at the desired temperature in air. After the removal of surface oxide by mechanical and chemical means, the oxygen content was determined in the underlying metal. In general, this process of saturation, with a few modifications, was followed by the present writers. Although the procedure is direct and has obvious advantages, its effectiveness, unfortunately, is reduced by an excessive scaling of the copper, particularly at the higher temperatures. After saturation treatments above 900°C. the writers found that the specimens, necessarily rather thin in the original condition, consisted largely of scale and yielded too little metal for a satisfactory analytical sample. Furthermore, great difficulty was experienced in effecting complete removal of the scale. Needless to say, it is necessary to exercise extraordinary care in the preparation of the surface of the analytical sample in order to eliminate submicro-scopic fragments of cuprous oxide which ordinarily are lodged in the crevasses and

Jan 1, 1941

By E. N. Skinner, Arthur Philliops

During the course of an experimental program concerned with the hydrogen embrittlement of copper containing oxygen in concentrations within the solubility limits it became necessary to make a critical appraisal of the literature dealing with the solubility relationships of oxygen and solid copper. The latest determinations, and perhaps the only data obtained on "spectroscopically" pure copper, are those of Rhines and Mathewson' who reported that the solid solubility increases from 0.007 per cent oxygen at 600°C. to about 0.01; per cent at 1500ºC. Hanson, Marryat and Ford2 had previously placed the solubility limit at less than 0.009 per cent oxygen at 1000ºC. and Allen and Street3 had suggested, on the basis of an unpublished research by T. Hemitt, not over 0.005 per cent oxygen at 500°C. In the introductory stages of the investigation indirect evidence accumulated to suggest that the solubility limits were significantly lower than those previously reported. For this reason it was deemed essential to clarify this point before proceeding with a program intended to establish a quantitative relationship between hydrogen embrittlement and oxygen concentrations positively known to be within the solid solution range. Furthermore, the increasing production and the highly selective applications of the commercial "oxygen-free" coppers inevitably direct attention to the practical necessity for exact knowledge regarding the effects of mini-tie concentrations of the elements ordinarily found in the high-purity coppers now available. Of these elements oxygen occupies a unique position, not only by virtue of its specific effects on copper but more particularly in view of its important reactive tendencies toward the other impurities with which it is associated. Rhines and Mathewson considered several methods for measuring the solubility of oxygen and finally adopted the simple plan of saturating the specimens, obtained from redeposited cathode copper, by heating at the desired temperature in air. After the removal of surface oxide by mechanical and chemical means, the oxygen content was determined in the underlying metal. In general, this process of saturation, with a few modifications, was followed by the present writers. Although the procedure is direct and has obvious advantages, its effectiveness, unfortunately, is reduced by an excessive scaling of the copper, particularly at the higher temperatures. After saturation treatments above 900°C. the writers found that the specimens, necessarily rather thin in the original condition, consisted largely of scale and yielded too little metal for a satisfactory analytical sample. Furthermore, great difficulty was experienced in effecting complete removal of the scale. Needless to say, it is necessary to exercise extraordinary care in the preparation of the surface of the analytical sample in order to eliminate submicro-scopic fragments of cuprous oxide which ordinarily are lodged in the crevasses and

Jan 1, 1941

By W. C. Hagel, H. J. Beattie

Seven austenitic alloys of varions base compositions and minor-alloy additions were solution-treated, aged systematically between 1200oand 1800oF, and examined by X-ray and electron metallography. Intragranular preczpitations of µ, Laves, s, ?', Ni3Ti, and x phases were observed as a function of composition and aging time and temperatwre. Phase solubility limits were detevtnitzed within 100Fo intervals. These inter metallic compounds fall into two distinct general classes, and whichever class predomznates depends on base composition. It has become increasingly evident that multicom-ponent austenitic alloys are well characterized by their precipitation processes. Since certain groups of elements act as one, the relationships among these processes are reasonably simple; complete identification of such processes is usually attainable by a systematic aging study with a combination of techniques centered on microscopy and diffraction. Several nickel- and cobalt-base alloys illustrating cellular precipitation and its interaction with general precipitation were reported previously.1 The group of alloys covered in the present paper demonstrates precipitation-hardening reactions involving two distinct classes of intermetallic compounds where the predominating class appears to depend on base composition. This dependency ties in with a crystal-chemistry regularity first observed some twenty years ago by Laves and Wallbaum but never amplified to our knowledge. Results of electron-microscope and X-ray diffraction studies on systematically aged hot-rolled alloys known commercially as S-816, S-590, Rene-41, Incoloy-901, M-308, and M-647 are reported here. Some of these alloys have previously undergone minor-phase analyses by other investiators. Alloy S-816 was investigated by Rosenbaum, Lane and Grant,3 and Weeton and Signorelli.4 Rosenbaum found only CbC in hot-rolled bars. Lane and Grant found CbC and a small amount of M6C in the cast structure and stated that both carbides form during aging, most of the precipitation being CbC. Weeton and Signorelli found CbC, M23C6 and a weak indication of a phase after a slow step-down cooling cycle from 2250°F. Rosenbaum also investigated hot-rolled samples of S-590 and identified CbC and M6C. Preliminary information on Rene-41, gained partly from the present work, was reported by Morris.5 Long-time precipitation phenomena in Incoloy-901 at 1350°Fwere investigated by Clark and Iwanski.B heir raw data re- semble those of our present heat with 0.1 pct B, while their interpretation of these data resembles our interpretation of data from another heat with only 0.001 pct B; they made no statement as to boron content. No previous minor-phase studies of alloys M-308 or M-647 have been reported. EXPERIMENTAL METHODS Table I gives alloy compositions in both weight and atomic percent. Specimens were solution-treated from 1700º to 2200ºF, aged at logarithmic-time intervals up to 1000 hours between 1200 and 1800 F, and examined in accordance with procedures previously described in detail. ' ' Phase extractions were carried out in electrolytic cells containing 800 ml of either 7 pct HC1 in denatured ethanol or 20 pct H3PO4 in water. After electrolysis for 48 hr at 0.1 to 0.2 amp per sq inch, residues were separated by filtration or centrifuging. X-ray powder patterns of residues were recorded on a diffractometer for accuracy and on film for sensitivity. Lattice parameters were calculated by least-squares analyses of indexed sin 8 values, and relative abundances were estimated from intensities of strongest lines of each phase. These phase abundances denote relative amounts with respect to each other rather than to the alloy. Mechanically polished specimens were etched in a freshly mixed solution of 92 pct HC1, 5 pct H2SO4, and 3 pct HNO3. Parlodion replicas for the electron microscope were chromium-shadowed in high vacuum at a glancing angle of 20deg. All electron micrographs are reproduced here with the shadowing source above. The correspondence betweenelectronmicrostructures and phases identified by X-rays was established by a high redundancy of correlation between relative amounts at different stages of aging and examination above and below critical transformation or solubility temperatures. EXPERIMENTAL RESULTS S-816 and S-590—The phases found in S-816 and S-590 after various aging and solutioning treatments are listed in Table 11. These data and the observed

Jan 1, 1962

By Hugh S. Spence

THE use of natural feldspathic rocks, as opposed to straight feldspar, for ceramic purposes is not new. "Cornwall stone," a semi-kaolinized granite containing fluorite, has long been used by the English pottery trade instead of feldspar, and "Carolina stone," a similar rock, is now being offered to the American trade. A recent report of the U. S. Bureau of Mines states that trachyte, a glassy volcanic rock, is being used in California instead of feldspar in ceramic bodies. In Germany, phonolite and basalt have been investigated, and possibly also used, as ceramic raw materials, and extensive research has been conducted in Russia in recent years looking to the utilization of the immense bodies of nepheline syenite of the Kola Peninsula, which is the host rock of the apatite deposits now being exploited on a large scale in the Murmansk region; the nepheline is recovered as a by-product of the concentration of the apatite. Long used principally as a raw material for the pottery and allied industries, where, in bodies, glazes, enamels, etc., it serves as a fluxing ingredient and forms, on firing, a glassy bond with the more refractory clay, flint and coloring particles, feldspar has been finding ever increasing employment in glass. In 1936, over half of the nearly quarter of a million tons of feldspar sold in the United States went to the glass trade. Its usefulness for this purpose is due to the resistance to thermal shock which it imparts to glass products, particularly bottles, containers and tableware, because of its alumina content, which averages from 16 to 20 per cent. Active search has been made on the American continent during the past few years for other minerals of feldspathoid type, with comparable or higher alumina content, that may be suitable for glass and other ceramic purposes. One of the most important results of this work has been the delimiting in central Ontario of large bodies of nepheline syenite of excellent ceramic grade.

Jan 1, 1938

By C. O. Ensign

Results of the application of geo1ogic knowledge to grade control have been remarkable. Grade reduction from dilution has been diminished from greater than 9% at the time of the program's beginning to about 2% at present. This has resulted in an increase of about 1.8 lb of copper per ton of ore mined and has made a substantial contribution to earnings at White Pine during the past two years. Even more improvement is expected in the future. The White Pine orebody, situated in the southwestern portion of the Keweenaw peninsula of upper Michigan, is a gently dipping stratiform or bedded deposit. Copper distribution is stratigraphi-cally controlled with higher values being confined to specific beds in the ore column. Room-and-pillar mining is practiced. Mining technique and geologic characteristics present a special array of problems in controlling the grade of ore. A routine program of grade control was started in the White Pine mine in August 1961. The program is based upon development and application of geologic knowledge to assist mine operating personnel to increase the grade of ore, primarily by accurate stratigraphic control and selection of areas for development on the basis of grade distribution trends. Geologists work closely with mine supervisors to offer the necessary geologic guidance. STRATIGRAPHIC POSITION OF COPPER The important rock series in the White Pine area is comprised of three formations of late Precambrian age. In descending order they are the Freda sandstone, Nonesuch shale, and Copper Harbor conglomerate. The Nonesuch shale is about 600 ft thick. Economic copper concentration occurs only in the lowermost 20 to 25 ft of the formation; however, within a restricted area along the southwest side of the mine the uppermost 1 to 7 ft of the Copper Harbor conglomerate (lower sandstone) contain sufficient quantities of copper to be included in the ore column. The ore consists primarily of chalcocite with subordinate native copper disseminated in shales, siltstones, and sandstones. MINE BOUNDARIES AND STRUCTURE The mine area is bounded on the west by the sub-outcrop of basal Nonesuch at bed rock surface and on the southwest by the White Pine fault (Fig. 1). The south and southeast limit of the orebody is reasonably well delineated by thinning or pinch-out of favorable host beds. Northern, northeastern, and eastern limits have not been established. The White Pine fault is actually a wide zone of shearing which strikes approximately N 40° W. It is downthrown on the southwest side and dips steeply to the northeast. Maximum vertical displacement is about 1500 ft.

Jan 1, 1964

By F. Morgan, M. Muskat, R. G. Russell

Core experiments with radioactive tracers are reported in which an artificial radioactive material, radiovanadium, was used in aqueous solution in a study of the mobility of connate water. Sandstone cores saturated with active water were first oil-flooded to simulate virgin sand conditions in which the pores are filled with oil and connate water. They were then subjected to flooding with inactive water. Measurements were made of the activity of various portions of the effluent as well as the activity of the core after the flooding process was completed. In additional experiments the distribution of activity along the core was measured during the flooding process. In still other experiments direct flooding tests were made on cores fully saturated with active water. In all cases it was found that after injecting into the core a volume of inactive water equal to a pore volume, the effluent contained more than 80 per cent of the active content originally in the core. It is felt that these results imply a high degree of mobility of the connate water when subjected to flooding, although at least a partial contribution of the effect of tracer transfer within the core cannot be definitely excluded. The implications of this result with respect to water-flooding, core analysis and electric logging are discussed. A better approach to determining the connate water saturation of oil-producing rocks, by measuring the fluid content of core samples at the surface, is by the use of crude oil or oil-base muds as the coring fluid. Although water flooding is of considerable importance in the recovery of ail, comparatively little is known with certainty about the role played by the connate water during the operations. Two possibilities exist. Either the connate water is retained in the formation while the flood water sweeps past, or it is pushed along to a greater or lesser degree by the flood. Thus far no explicit recognition in terms of quantitative studies appears to have been given to the displacement of connate waters by the intruding extraneous waters, although such a possibility might be important in determining the efficiency of the oil -displacement process in water-flooding operations, especially in argillaceous rocks. On the other hand, it is a common observation that the first water produced with the oil as a result of water-flooding is definitely saline.*.' Similar questions regarding the mobility of the interstitial water arise in the quantitative description of the advance of edge-water drives. In the interpretation of the water saturations determined from core analyses, when coring with water-base muds, it is generally assumed that the drilling fluid merely adds to the connate water without displacing the

Jan 1, 1947

By M. Muskat, F. Morgan, R. G. Russell

Core experiments with radioactive tracers are reported in which an artificial radioactive material, radiovanadium, was used in aqueous solution in a study of the mobility of connate water. Sandstone cores saturated with active water were first oil-flooded to simulate virgin sand conditions in which the pores are filled with oil and connate water. They were then subjected to flooding with inactive water. Measurements were made of the activity of various portions of the effluent as well as the activity of the core after the flooding process was completed. In additional experiments the distribution of activity along the core was measured during the flooding process. In still other experiments direct flooding tests were made on cores fully saturated with active water. In all cases it was found that after injecting into the core a volume of inactive water equal to a pore volume, the effluent contained more than 80 per cent of the active content originally in the core. It is felt that these results imply a high degree of mobility of the connate water when subjected to flooding, although at least a partial contribution of the effect of tracer transfer within the core cannot be definitely excluded. The implications of this result with respect to water-flooding, core analysis and electric logging are discussed. A better approach to determining the connate water saturation of oil-producing rocks, by measuring the fluid content of core samples at the surface, is by the use of crude oil or oil-base muds as the coring fluid. Although water flooding is of considerable importance in the recovery of ail, comparatively little is known with certainty about the role played by the connate water during the operations. Two possibilities exist. Either the connate water is retained in the formation while the flood water sweeps past, or it is pushed along to a greater or lesser degree by the flood. Thus far no explicit recognition in terms of quantitative studies appears to have been given to the displacement of connate waters by the intruding extraneous waters, although such a possibility might be important in determining the efficiency of the oil -displacement process in water-flooding operations, especially in argillaceous rocks. On the other hand, it is a common observation that the first water produced with the oil as a result of water-flooding is definitely saline.*.' Similar questions regarding the mobility of the interstitial water arise in the quantitative description of the advance of edge-water drives. In the interpretation of the water saturations determined from core analyses, when coring with water-base muds, it is generally assumed that the drilling fluid merely adds to the connate water without displacing the

Jan 1, 1947

By G. S. Scott, G. W. Jones

ECONOMIC waste caused by mine fires may become considerable,15 especially if a fire is allowed to spread or temporarily to get beyond control. It is important, therefore, to act promptly whenever a fire is suspected and to make every action count. To contribute toward its extinction effectively it is necessary to know at the earliest possible moment, and continuously thereafter, what is happening at the seat of the fire, which may be in a remote or inaccessible area, and also to recognize what may be expected as a result of any proposed combative measure. In combatting a fire the mining engineer and the chemist should cooperate, first deciding upon the course of action to be taken and then drawing upon the mining engineer's intimate knowledge of the physical structure of the fire area, the cost and time required to carry out proposed operations, and the probable efficiency with which these operations could be performed, and upon the chemist's knowledge for the results to be expected therefrom. After the initial steps to be taken have been decided, it devolves upon the mining engineer to see that they are carried out and upon the chemist to evaluate the results and to keep the mining engineer continuously informed in regard to a variety of matters-such as the composition and toxic or asphyxiating properties of the atmosphere in which the men may be working, whether the fire is increasing or decreasing in intensity and its probable temperature, the quantity of air leakage and the explosion hazards of the fire area. The purpose of this paper is to discuss what the chemist can and cannot contribute as a member of the fire-fighting personnel. The technical literature contains several hundred papers relating directly and indirectly to mine fires, and this fact alone is testimony to the complex nature of the phenomena involved in the birth, life, and final demise of a fire. A fire may be stopped (I) by preventing oxygen from reaching the coal or (2) by removing the conditions necessary for the rapid reaction of coal with oxygen; i.e., decreasing the temperature. All methods of prevention or control. necessarily must be based upon one or the other, or both, of these two principles. . The chemistry of a fire may be understood readily if the low-temperature oxidation of coal is considered as a starting point; then oxidation at higher temperatures (or combustion) ; and with these, the composition of the solid and gaseous products resulting from the oxidation or from the effects of the heat liberated. This discussion refers particularly to Pennsylvania anthracite, although much of the material applies equally well to coals of lower rank. OXIDATION OF COAL Oxidation of coal fundamentally is confined to the surface; that is, the rate at which oxygen penetrates into the interior of a solid block of coal is so slow that it may be ignored.6,16 Oxidation starts when a fresh surface is exposed, and the rate is

Jan 1, 1942