Search Documents

By C. E. Johnston

In December 1956, International Minerals & Chemical Corp. installed a rope-suspended belt haulage system in its Carlsbad, N. M., potash mine to complement the already existing rail transport arrangement. In this article the author describes when and where each system is used, the advantages and disadvantages of both, and future planning and proposed changes in haulage at IMC. The haulage system at the International Minerals & Chemical Corporation (IMC) potash mine near Carlsbad, N. M., reached a turning point in December 1956 with the introduction of rope-suspended belt haulage. In fact, IMC pioneered the use of this type of belt in the potash industry. Since that time belt conveyance has been employed as an extension of the rail system but not as a replacement of the main rail haulage. IMC's potash mine is located in the Permian Basin, approximately 20 miles east of Carlsbad in Eddy County, N. M. The 800, 850 and 900-ft levels have been exploited. From these levels over 60 million tons have been extracted. The two ore minerals are sylvite (KCl) and langbeinite (K2SO4. 2MgSO4). The principal gangue mineral is halite, with minor amounts of polyhalite, kainite and leonite. Langbeinite is mined on the 850-ft level and sylvite on the 900. The 800-ft level, with both langbeinite and sylvite mineralization, is idle. Mining heights vary from 54 in. to over 10 ft. A room and pillar mining system is used. Geologically, mining is done in the Salado salt formation. The U.S. Geological Survey has classified the 900-ft sylvite level as the first ore zone and the 850-ft langbeinite level as the fourth ore zone. Since the grade of sylvite is low, mineralization at the IMC mine is somewhat irregular and salt horses, are common. Selective mining and a flexible haulage

Jan 1, 1963

By David M. Parkes, Junie Lindsay

A review of the movement of coal in water is undertaken from a practical rather than a theoretical view point. Installations are described in which coal is transported on gradients down to 2.5' and others which move coal at a water-coal ratio of 1:l by weight. The water cycle of the hydraulic mining system is discussed. In many applications this can be a closed circuit. The coal dewatering system is illustrated, making particular reference to the problems of storage of coal-water mixtures between the mine and the plant. Water treatment is done in thickeners down to 100 ppm which is normally sufficient for re-circulating through high pressure pumps and monitors.

Jan 1, 1978

By J. C. Martin

A theoretical analysis of steam stimulation is presented for single sands. The analysis includes the effect of steam production and most of the effects of heat conduction. The results show the effects of a number of important variables on the performance of an idealized well under steam stimulation. Calculated responses are presented which indicate the effects of steam production, amount of steam injected, water production, formation thickness and formation damage. Results indicate that steam production can cause large reductions in the heat contained in the formation. This effect can be eliminated by drawdown control. Water production reduces the amount of oil produced during stimulation. The optimum amount of steam to inject depends on economic factors as well as the well response. In many cases, the increased temperature resulting from stimulation reduces oil viscosity near the well sufficiently to overcome the effects of formation damage even if the damage is not removed during steam injection. Calculated responses for thin sands are more favorable than anticipated. INTRODUCTION Little has been published on the theory of steam stimulation'-' despite the interest it has created and the wide variation in well responses. The results of the present analysis provide an insight into steam stimulation, and the methods employed provide a foundation for future work. Analyses presented in Refs. 1 and 2 are very limited and apply to gravity drainage conditions. Ref. 3 contains an analysis similar to the one presented here. The idealized models used and the assumptions made in Ref. 3 are different from those used in this paper. The analysis assumes that after steam injection has heated a small portion of the volume within the radius of drainage of a single uniform sand, a shut-in soaking period is allowed before returning the well to production. The effects of gravity, capillarity, transient pressure and water-sensitive sands are neglected. The injection and soaking times are assumed short compared to the stimulated production time. The initial temperature is assumed uniform; thus, the results apply primarily to first-cycle stimulation. The effects of gas production other than steam are neglected, and the water-oil ratio during production is assumed constant. Steam stimulation involves the simultaneous variation of the temperature, pressure and saturations. General mathematical equations for these variations are complicated and can be very difficult to solve. Simplified equations based on idealized models are used to reduce the mathematics sufficiently to allow approximate solutions to be obtained. DISCUSSION INJECTION An idealized model for which heat conduction is neglected is used to represent the behavior of a well during steam injection. The mathematics for this model is presented in Appendix A which also contains an approximate solution for the behavior of the no-conduction model. SOAKING During soaking, the well is shut in. Only the temperature, pressure and saturation distributions at the end of soaking are needed in the analysis. During soaking the heat is considered to be conducted in a uniform medium from an initially uniformly-heated circular cylinder confined to the producing interval. At the end of soaking the saturations and pressures are assumed to correspond to the cold zone. Analysis of the heat flow during soaking is included in the next section. The radius of the heated cylinder is calculated from the following heat balance (for constant quality steam injection). At the end of the soaking period it is assumed that little or no free gas is present near the well, and that the soaking period has been sufficiently long that the steam zone has had time to expand and the steam has condensed. The condition where there is no soaking is considered in the next section. PRODUCTION In this section, an approximate method is presented for solving the equations of heat and fluid flow associated with the production of oil and water during steam stimulation. Where initial pressure drawdowns are sufficient to cause steam to flow into the wellbore, steam production is assumed to occur within a short initial adjustment period (Appendix B). The production practices followed soon after the well is returned to production can have a large influence on the amount of oil produced during the stimulation cycle. Under most conditions, there is a period of time in which some or all of the water in the heated zone is converted into steam and produced. This flashing of hot water is caused by the pressure in the heated zone dropping below

By J. W. Moody

The first Rodpeb mill ever built and placed in full scale successful operation went onstream in mid- 1960 at Marquette Cement Manufacturing Co.'s newly modernized portland cement production plant at Nashville, Tenn. It replaced a third stage of fine crushing and two 7x22-ft Compeb mills in the wet raw slurry grinding department. The Rodpeb mill at Nashville is similar in appearance to a Compeb mill but is larger. The mill, which operates in open circuit, is 9 ft in diameter and 38 ft long. The rod compartment is 12 ft long, with the rods being 11.5 ft in length and ranging in diameter from 4 in. down to about 1 in. The weight of the rod charge is 100,000 lb. The liners of the rod compartment are of the Lorain design.

Jan 4, 1963

By J. B. Clemmer, P. E. Churchward, C. Rampacek

A cyclic method for processing manganese ores using sodium sulphate as the basic reagent is described. Sodium sulphate is electrolyzed in a diaphragm cell to give an anolyte-containing agentisdescribed.Sodiumsulphuric acid and a catholyte-containing iselectrolyzedincaustic soda, a part of which is carbonated in a cyclic manner to form soda ash. The reduced ore is leached with the anolyte to dissolve the manganese and the impurities are precipitated by addition of catholyte. Manganese in the pregnant todissolvethemanganeseandtheimpuritiessolution is precipitated as synthetic rhodochrosite with a carbonated catholyte, and sodium sulphate is regenerated. Calcining the manganese carbonate gives a high grade product and the carbon dioxide is returned to the carbonation step. The results of laboratory tests using cells equipped with synthetic-fiber diaphragms and permselective membranes, which permit transfer of anions or cations during electrolysis, are described. A METHOD which has been considered for pro-cessing manganese ores under emergency conditions to recover a product suitable for smelting to ferromanganese involves reductive roasting of the ore for leaching with dilute sulphuric acid followed by precipitation of the manganese from the purified pregnant solution with sodium carbonate. Although the process is operable and involves no novel or untried steps, it is noncyclic in regard to reagents. Research seemed warranted to determine if a cyclic process could be developed by electrolyzing the sodium sulphate formed during precipitation of the manganese with soda ash to regenerate sulphuric acid and sodium hydroxide. Reduced ore would be leached with acid anolyte to dissolve the manganese. The iron, alumina, and other dissolved impurities would be precipitated with the caustic catholyte, and the manganese in the purified pregnant solution would be precipitated as artificial rhodochrosite with carbonated catholyte to regenerate simultaneously sodium sulphate for electrolysis. Waste boiler gas and CO, from calcining the manganese precipitate would be recycled for carbonation of the caustic catholyte. There is a surprising lack of data in the technical literature on diaphragm electrolysis of sodium sulphate. One of the more comprehensive papers, by Atwell and Fuwa, describes the problem involved in electrolyzing byproduct sodium sulphate from the viscose process with particular regard to the design and operation of asbestos diaphragm cells. Frisk' also investigated electrolysis of sodium sulphate from viscose-spinning baths to recover caustic soda and sulphuric acid. The objective in these investigations was to produce, by electrolysis and evaporation, a concentrated caustic-soda solution and a sulphuric-acid solution low in sodium sulphate. Because of these requirements, the process was not too attractive despite a favorable yield of caustic and acid with a reasonable power consumption. Because strong acid and base are not required for processing manganese ores and nonelectrolyzed sodium sulphate is not objectionable in either reagent, the present problem was somewhat simpler than that of these investigators. The purpose of this report is to summarize briefly the results of laboratory electrolysis of commercial sodium sulphate in diaphragm cells of different types and the application of the acid and caustic for processing manganese ores in a cyclic manner. Electrolysis in Permeable Diaphragm Cells The principal problem in electrolyzing sodium sulphate in a permeable diaphragm cell is to prevent mixing of the acid and base formed in the anode and cathode compartments. It is not enough to separate the anolyte and catholyte by a single diaphragm. A three-compartment cell in which the sodium-sulphate solution is fed to the center compartment and flows through the permeable diaphragms to the anode and cathode compartments is more efficient electrically. Diaphragms should be porous enough to allow flow of solution to outer compartments but tight enough to prevent gross mixing of the anolyte and catholyte. In addition to being resistant to acid and alkali, the diaphragms should offer minimum resistance to the flow of current. It is also important that the electrolyte contain a high concentration of sodium sulphate to furnish an abundance of sodium and sulphate ions and thereby decrease the current carried by hydrogen and hydroxyl ions. A practical limitation of sodium-sulphate concentration is imposed by the decreased solubility of sodium sulphate with decreasing temperature. At 20°C, a concentration of 200 g per liter sodium sulphate can be maintained. Little is gained in conductivity by using a concentration greater than 200 g per liter. The small-scale continuous electrolysis tests were made in a 12x12 in. open-top bakelite cell equipped

Jan 1, 1956

By C. P. Miller

In order to determine the usefulness of geochemical and biogeochemical prospecting for nickel, ten localities representing several types of nickel occurrences were selected as sites from which to collect plant and soil samples. This report covers the investigations in two of the areas. After a brief geologic description of the areas, the author presents details of the experimental tests and resulting data. Conclusions drawn from the studies led to several general guides for further prospecting. In a study of the usefulness of geochemical and biogeochemical prospecting for nickel made about three years ago, approximately ten localities, representing several different types of nickel occurrences, were sampled and about 1500 samples of plant and soil were collected. This report will cover briefly the data and results for two areas, and a summary of guides for prospecting. DESCRIPTION OF AREAS SAMPLED One locality is the Red Flats nickel prospect in Curry County, Ore., about six miles southeast of Goldbeach, and the other is the Little Rocky Creek prospect in Stillwater County, southcentral Montana, just southeast of the Benbow chromite mine. The Oregon area is a lateritic-type nickel deposit formed on a nickel-rich serpentinite peridotite complex, similar to the Josephine intrusion in southwestern Oregon. The Montana area is a nickel prospect in norite, peridotite, and related rocks of the Stillwater igneous complex. The Stillwater complex is a series of layered basic and ultrabasic rocks, with a layer of norite-gabbro at the base and a series of peridotites and gabbros above. The nickel in the Oregon deposit occurs in both the peridotite and the overlying soil. A deep lateritic soil is developed locally on the peridotite and serpentinite and constitutes the ore. The average nickel content of the lateritic soil is less than 1 pct, whereas the nickel content of the weathered peridotite is about 1 to 1.5 pct. The nickel occurs as garnierite (Mg, Fe, Ni, Mn)3 (OH)4 (SiA1)2O5 in the soil and in the olivine and pyroxene in the peridotite where it probably substitutes for Fe2+ or Mg2+ in the silicate lattices. Nickel is found in three distinct ways in the Still-water rocks: 1) it is in the olivine and pyroxene minerals in norite, harzburgite, etc.; 2) it occurs as widely disseminated grains of pentlandite-pyr-rhotite, which tend to be concentrated in the lower norite band; and 3) it occurs as discrete bodies of pentlandite-pyrrhotite and chalcopyrite which are localized in the norite zone, close to the contact with the underlying rocks. The nickel content of the norite is probably less than 1 pct, and the nickel content of the pods and lenses within the norite is about 1 pct. PROSPECTING APPROACH Although the areas are different geologically, the approach in prospecting them is fundamentally the same. The procedure is twofold: 1) a rapid reconnaissance survey to outline an area of high nickel content, and 2) a more detailed survey to outline zones of possible ore grade within the area of high nickel. The possible ore at Red Flats is concentrated in the lateritic soil, whereas at Little Rocky Creek it is in the sulfide pods. Both types are surrounded by an area of relatively high nickel content. CHEMICAL ANALYSIS Chemical analyses of nickel were made by a di-methylglyoxime colorimetric test, similar to the standard test for nickel, utilizing concentrated sul-furic acid for extraction. The lower limit of detection for nickel in soil by the method used was about 10 ppm and for nickel in plants about 5 ppm. The relative deviation was about 25 pct. SOIL PROSPECTING General Statements: A summary of the approximate average parts per million of nickel in soil, as compiled from the literature and from my study, is given in Table I. Selected references are given at the end of the paper. Few of the investigators reported the type of extraction or analysis, so the data given may not be strictly comparable to mine, which were made with a sulfuric acid extraction. Any nickel concentration greater than these average values might be considered anomalous, although each area must be studied in relation to the surrounding rocks. Method of Soil Sampling: The soil samples were taken in a zone from 1 in. to 1 ft below the humus layer, and within a 15-ft radius around a station.

Jan 1, 1961

By Winston A. Wong, John J. Jonas

Commercial purity aluminum was deformed by extrusion over the temperature range 320° to 616°C and the strain rate range 0.1 to 10 per sec. Flow stresses and strain rates were calculated from the experimenLa1 ram pressures and speeds. The stress-strain rate-lemperature relationship in extrusion was found to be similar to that in creep. Extrusion, torsion, compression, and creep data extending over ten orders of magnitude of strain rate and over two orders of magnitude of stress were correlated by a single creep equation. It was concluded that hot-working is a thermally activated process, in which the rate-controlling mechanism is either the climb of edge dislocations or [he motion of jogged screw dislocations. The microstructural changes observed during extrusion were consistent with the proposed deformation mechanisms. ALTHOUGH great progress has been made in understanding the technology of extrusion, very little is known about the actual deformation mechanisms operating during flow. Previous accounts describing extrusion have indicated that the relationship between ram speed (V), pressure (P), and temperature (T) can be given as follows:1 V = apb and P = A' exp(-AT). In these equations, a and b are constants which depend on temperature, A' is a constant which depends on ram speed, and A is a "coefficient" with a different value for each metal. Although these equations have fairly wide application, they do not contribute much to a fundamental understanding of the deformation. Furthermore, extrusion has not hitherto been considered as a thermally activated rate process. This lacuna is surprising because hot-working is similar to high-temperature creep in several respects. There is, in fact, a fair body of experimental evidence suggesting that the material response under hot-working conditions is similar to that occurring under creep conditions, in spite of the many orders of magnitude difference in strain rate.2"4 Since creep has been extensively analyzed in terms of dislocation mechanisms, the comparison of hot-working to creep is useful, for it can suggest the possible deformation mechanisms operating during hot-working. In this paper, the hot extrusion of aluminum will be examined from the point of view of thermally activated deformation mechanisms, such as operate during creep. EXPERIMENTAL PROCEDURE The experimental procedure consisted of extruding commercial purity aluminum* over a range of ram velocities and temperatures at constant die reduction by the direct method. Details of the experimental equipment have been published elsewhere.5 Extrusion was carried out at each of the following billet temperatures: 320°, 376°, 445°, 490°, 555°, and 616°C at the following constant ram speeds: 0.002, 0.008, 0.02, 0.1, and 0.2 in. per sec.* All results were obtained using a square-shouldered die with an extrusion ratio of 40:1, giving a reduction in area of 97.5 pct. The ram force was the dependent variable, and was measured by means of strain gages on the ram and was plotted as a function of ram travel. The sequence of events before making an extrusion was duplicated before each run so as to minimize as much as possible variations in experimental conditions. For example, after the equipment had been assembled, the billet was allowed to heat up to temperature inside the insulated container. Once the container attained the desired temperature, a period of 1/2 hr was allowed to elapse before the extrusion was made. This time was found to be required to allow the billet to reach a steady-state temperature, as determined from previous tests. When all was ready, extrusion was carried out without interruption; that is, the billet was upset and extruded in one operation. EXPERIMENTAL RESULTS AND DISCUSSION The two usual experimental approaches for investigating high-temperature deformation exhibit an important common feature. In the first approach, which corresponds to creep, a constant stress (or load) is applied to the material at constant temperature and the resultant strain is recorded against time. After an initial transient stage, a state of constant strain rate exists (secondary creep), in which a steady-state condition is established which is sensitive to variation in either applied stress or temperature. In the second approach, a constant strain rate is applied and the resultant flow stress is recorded. This corresponds to the situation in hot torsion or hot compression, where it is observed that, for a constant test temperature, there is an initial rise in stress to a steady value which is maintained up to very high strains. In tests of this type, a steady-state region is also established in which the stress is sensitive to variation in either the strain rate or the temperature.3,4,6-16 In both types of tests, therefore, a steady-state region is established after an initial transient. In the case of hot-working this region may be called steady-state hot-working, and it is analogous to steady-state creep with which it has many common features. Stress Dependence of the strain Rate in Extrusion. In order to assess the stress dependence of the strain rate under extrusion conditions, and to compare it to that of creep, as well as of hot torsion and hot compression, the extrusion data were analyzed according to power, exponential and hyperbolic sine creep equations.

Jan 1, 1969

By A. W. Cochardt

THERE are a number of effects that can cause material damping or internal friction. Some of these are frequency dependent, such as the thermo-elastic effect' and the stress-induced ordering.' Others depend on the amplitude of vibration, i.e., the damping related to the motion of dislocations3 and that due to magneto-mechanical hysteresis.' While many of these effects have been studied, only the magneto-mechanical effect has found extensive practical application. It is the principal source of damping in the current blade material in steam turbines.A magneto-mechanical hysteresis loop is seen in Fig. 1. If an unmagnetized, polycrystalline wire of a material exhibiting magneto-mechanical hysteresis, such as an Fe-14 pct A1 alloy, is twisted in torsion, a relation between shear stress and shear strain y is observed as indicated. The stress-strain curve does not follow Hooke's law -dashed line. Instead, the strain y increases nonlinearly and partly irreversibly, due to the motion of ferromagnetic domain walls,* until a critical stress is reached, which in this case is about 3,500 psi. If the applied stress is raised further, the strain appears to increase linearly and reversibly in accordance with Hooke's law, since all domains are now aligned in easy directions of magnetization nearest to the direction of the applied stress, and plastic flow has not yet started noticeably. On removing the applied stress, a remanent shear strain y, is observed, which is related to the irreversible magnetostriction of the material.' The energy dissipated in the material during a stress-strain cycle is proportional to the critical stress t, and the remanent magnetostrictive shear strain 7,. The purpose of this investigation was to make a survey of the magneto-mechanical damping of ferro-

Jan 1, 1957

By H. Rumfelt

The author demonstrates an approach for analyzing overcasting requirements for a stripping project. This approach to the problem employs indicated trends in the relationship of the weight of the machine (only electropowered draglines are considered) to its ability to do stripping work. Strip mining in the domestic coal industry is contributing a greater proportion of overall production than at any time in the past. U.S. Bureau of Mines statistics show that the percentage of total production mined in 1958 by stripping methods increased to more than 30 pct, up from 22 pct in 1951. The tendency to favor strip and open pit mining exists in other mining activities, but such trends are not as clearly outlined as in the coal industry. Significantly, the depth of overburden in coal properties considered suitable for stripping is also increasing. A depth of 50 to 60 ft of overburden was once considered to be about the maximum amount that could be handled economically. Today, a depth of 80 to 100 ft is frequently taken into consideration for simple overcasting operations (i.e., excavating overburden and dumping it in the spoil position where it remains indefinitely). Accompanying these changes, there have been continuing studies searching for procedures to appraise deeper stripping problems. Although the only known practicable way to accurately evaluate a proposed stripping venture is to make studies (including cost estimates) step by step, it is nevertheless desirable to have a quick method for making preliminary evaluations of potential strip mining operations. A recently devised digital computer method of providing a preliminary simple overcasting analysis for a stripping prospect relates the indicated trends in the relationship of the weight of the machine to its ability to do stripping work. In addition, this approach employs situations where the geometry of each cut-and-spoil section is assumed to take certain defined relationships for varying overburden depths. Slopes are necessarily considered to be stable, which means such practical factors as the mechanics of soils are neglected for the sake of convenience. Definition of Terms: Photographs A and B show a shovel-type and a dragline-type of simple overcast operation, plus terms used to denote certain parts of a pit. Pits that follow a straight line when projected on a horizontal plane are referred to as straightaway. It has been assumed that all section drawings accompanying this article pertain to straightaway cuts which, in turn, means that areas can be compared by relative volume. The volume of overburden is measured in virgin cubic yards. Material displaced from its virgin state to a spoil area normally occupies a larger volume than when in situ; the difference is termed swell, and it is expressed as a percentage of the original volume. For example, if the original cut volume is denoted V cu yd, and the spoil volume is 1.2 V cu yd, the swell is a positive 20 pct. MAXIMUM USEFULNESS FACTOR (MUF) CONCEPT Men experienced in overburden removal give emphasis to the weight of the machine in relation to its value as an excavator. From the writer's understanding, value has been only loosely defined and discussed generally and vaguely. The concept is considered important, however, since it is based upon the observations of many men. It provides a clue for the approach taken to solve deep stripping problems. In the procedure described below, value has been arbitrarily established as the product of the nominal dipper size of the shovel (or dragline) times a functional dumping reach. MUFs—Shovel: A shovel's capability to handle thick overburden is usually limited by its ability to dispose of the spoil. Thus the dumping reach, as well as its dumping height, is significant. The angle of repose of spoil material must also be considered. Although such slope angles vary among different mines, jobs, and materials, a slope of 1.25 to 1, frequently found in both planning and practice, is used by this author in the illustration of this analytical method. The relationship of the shovel's geometry to a stripping operation is shown in Fig. 1. To gain maximum advantage in constructing spoil piles, the shovel is placed so that its tracks adjacent to the spoil are as close as possible to the rib of the coal deposit. A vertical plane passing through the line

Jan 1, 1961

By P. V. Faragher

A METAL or alloy finds its place in commerce in proportion to its ability to serve certain purposes better and more economically than other materials. While there is some overlapping of the fields of application of the various metals under discussion in this symposium, each one has its uses for which it is especially adapted. While aluminum is the most recent of the metals to enter the field, the development of the industry has been based on its peculiar properties, by virtue of which new uses for non-ferrous metals have been created. There has been substitution of this new metal for other members of the group but there has been a far greater development in entirely new fields. In common with the other non-ferrous metals, aluminum is resistant to atmospheric corrosion. It also withstands the action of many of the common chemical reagents, strongly alkaline substances being the notable exceptions. The outstanding properties on which the application of aluminum is based are its low specific gravity and its ease of fabrication into the forms in which it is used. It is noteworthy that this property of specific lightness is retained in all the commercial aluminum-base alloys. This statement does not apply to aluminum bronze; this is more properly a copper-base alloy, since aluminum enters into its composition to the extent of only about 10 per cent. None of the commercial casting alloys of aluminum has a density exceeding that of the parent metal by more than about 10 per cent., and some are actually lighter. In the so-called "strong alloys" of aluminum in which strengths comparable to that of mild steel are developed by heat treatment, the greatest increase in density is only slightly more than 3 per cent., and one of these, also, is lighter than aluminum. This property of lightness combined with the desirable mechanical properties of the alloys, makes aluminum especially suited for parts of moving assemblies where saving in power, as well as a decrease in stresses resulting from inertia and vibration, are of importance.

Jan 1, 1928

By P. V. Faragher

A metal or alloy finds its place in commerce in proportion to its ability to serve certain purposes better and more economically than other materials. While there is some overlapping of the fields of application of the various metals under discussion in this symposium, each one has its uses for which it is especially adapted. While aluminum is the most recent of the metals to enter the field, the development of the industry has been based on its peculiar properties, by virtue of which new uses for non-ferrous metals have been created. There has been substitution of this new metal for other members of the group but there has been a far greater development in entirely new fields. In common with the other non-ferrous metals, aluminum is resistant to atmospheric corrosion. It also withstands the action of many of the common chemical reagents, strongly alkaline substances being the notable exceptions. The outstanding properties on which the application of aluminum is based are its low specific gravity and its ease of fabrication into the forms in which it is used. It is noteworthy that this property of specific lightness is retained in all the commercial aluminum-base alloys. This statement does not apply to aluminum bronze; this is more properly a copper-base alloy, since aluminum enters into its composition to the extent of only about 10 per cent. None of the commercial casting alloys of aluminum has a density exceeding that of the parent metal by more than about 10 per cent., and some are actually lighter. In the so-called "strong alloys" of aluminum in which strengths comparable to that of mild steel are developed by heat treatment, the greatest increase in density is only slightly more than 3 per cent., and one of these, also, is lighter than aluminum. This property of lightness combined with the desirable mechanical properties of the alloys, makes aluminum especially suited for parts of moving assemblies where saving in power, as well as a decrease in stresses resulting from inertia and vibration, are of importance.

By V. S. Tuman

In the first part of this paper, an estimate is made of the magnitude and extent of the thermal stresses which result from mud circulation. Our study is made for the period of relaxation, i.e., when the drilling operations are terminated and mud circulation is discontinued. In the second part, we have shown how the thermal stress can affect the wave propagation. An example is worked out for a Carbondale sandstone (Illinois basin). It is concluded that, in extreme cases when differential temperature is about 100°F, the travel time will be affected by about 2 microsec/ft. For more refined permeability studies, such corrections would be desirable. MAGNITUDE AND EXTENT OF THERMAL STRESSES RESULTING FROM MUD CIRCULATION When geological beds are penetrated by boreholes, it is observed that the formation temperatures increase with depth; however, the temperature profile varies considerably from place to place. During drilling operations, mud pumped from a pit at atmospheric temperature absorbs heat from the lower beds. As a result, the drilling fluid returning to the surface is at a higher temperature than the surrounding beds. The temperature gradient in a well depends on the rate of mud circulation and other factors; normally, this temperature gradient is smaller than the natural gradient in the formations. (See Fig. 1.) The temperature difference between the mud column and the surrounding beds gives rise to therma1 stresses (which are also important in the phenomenon of fracturing), and it is expected that they will affect the transit time of the sonic front in velocity logging.1 It is evident chat beds near the surface will undergo various cycles and will have a complicated dynamical and thermal-stress history. A limestone bed which is just penetrated will act as a source of heat, warming up the cold mud pumped down a few minutes earlier from the surface pit. The same limestone bed a week later will act as a sink, absorbing heat from the drilling mud which has already warmed up sufficiently to be at a higher temperature than the bed in question. No doubt a large section of the hole will undergo a heat treatment, which will make the calculation of the exact magnitude of the thermal stresses very difficult. In the solution of wellbore thermal equation, it is assumed that the rock around the wellbore is elastic and isotropic, and that the system is radially symmetrical. A complete dynamical solution of the thermal stresses set up at different horizons during the drilling operations would require a comprehensive history of the mud circulation, the surface temperature of the pit and the number of hours in which mud was not circulated. CONDUCTION OF HEAT AND THERMAL EQUATION OF STATE

By B. E. Hoffacker, R. E. Lund, J. Ferrighetto, G. E. Welch

Since October 1965 the Josephtown Smelter of St. Joseph Lead Co. has commercially applied the Heavy Media Separation process to reclaim zinc and reject gangue from electrothermic zinc furnace residues. In addition, heavy medium is produced from the ferrosilicon which is present in the furnace residues. By way of background, the Josephtown Smelter produces zinc metal and zinc oxide by the electro- thermic process. The principal feed to the vertical shaft electric furnaces is sized sinter and coke. Temperature of the charge in the furnaces varies from roughly 900°C near the wall to 1300-1400°C in the central regions. Zinc smelting is rapid and nearly complete in the main body of the charge, but little zinc is smelted near the wall. In addition to fusing high gangue content particles, the high temperatures promote side reactions, the most important of which is reduction of iron oxide and silica to form a low grade ferrosilicon containing about 82 % Fe and 13% Si.

Jan 12, 1968

By Ellis Clark

THE mining town of Pribram is situated in Central Bohemia, on the western slope of the Heiliger Berg, 30 miles southwest from Prague. Birkenberg, the village in which most of the shafts and ore-dressing establishments are situated, is built on a mountain of the same name. It is about a mile from Pribram, is 1700 feet above the sea, and is surrounded by graywacke rocks of Silurian origin, which are intersected by greenstone dikes, and in the southerly, southeasterly, and southwesterly direction are bounded by granite. The graywacke formations consist on one side of graywacke sandstone and quartzite, and on the other of graywacke slates. These last are separated from the first in the immediate vicinity of the mines by a graywacke seam converted into clay. For many years this so-cal led clay seam (lettenkkluft) was considered as a boundary of the ore deposits in both zones of graywacke. The graywacke formation is divided according to its hardness, structure, texture, and color, into fine, coarse, compact, slaty, whitish-gray, reddish-gray, and black graywacke. The, miner divides the formation into four divisions. The first or lowest division, which is in contact with the granite, consists of a fine-grained dirty gray slate; the -second is a very fine to a very coarse schist, white to reddish-gray in color, and rich in quartz, but containing little mica; the third consists of a slate with a contused cleavage, which has a dirty gray, dark gray, and very often black color and is often graphitic in its composition ; the fourth consists of a fine to coarse-grained graywacke schist, of a grayish-white or reddish-gray color, and rich in quartz. The cleavage in all four divisions strikes from northeast to southwest, and the dip is sometimes northwesterly, sometimes southerly, and often vertical. All four zones are cut through by a great number of diorite and greenstone dikes and chimneys. The thickness of these dikes, which are of

Jan 1, 1881

By W. A. Backofen, B. C. Wonsiewicz

The Plasticity transition in magnesium was studied by plane-strain compression of single crystals and polycrystalline material at temperatures from about 20" to 307°C. Reduction of single crystals along the c axis was accommodated by twinning on {1011) and retwinning on (10 12}, followed by basal shear in the doubly twinned volume. Deformation in that mode can result in sufficient independent shears for arbitrary shape change. Fracture in c axis compression, below about 100°C, has been related to excessive shear caused by unloading from the stress for {1011} twinning (-50 ksi at 20°C) to that for slip within the twin (-3 ksi); ductility follows from heating because the stress difference is lowered and the twin volume, in which elastic strain energy is dissipated on unloading, is increased. The stress for (1011) twinning is strongly temperature-dependent but not given by a critical resolved shear stress law. The latter is attributed to the influence of stress concentration from prior intersecting shear on nonbasal planes, the former to the temperature dependence of the preliminary slip. THE basic symmetry of hcp crystals has the effect of limiting the number of independent slip systems and making twinning an important deformation mechanism. The general result in wrought polycrystalline aggregates is a more or less sharply developed texture (or preferred orientation) which underlies a strong anisotropy in mechanical behavior. Knowing how the one influences the other is essential background for the use of such materials. Magnesium was of interest in this work because of the unexplained plasticity transition that it undergoes somewhere in the neighborhood of 200°c.''~ At lower temperatures plastic deformation before fracture in polycrystalline material is limited, while at higher temperatures extensive deformation is possible. The transition temperature commonly determines the lower limit of the range in which magnesium is worked. The limited ductility can be traced to a lack of independent crystallographic shears. A minimum of five are required for arbitrary shape change.' Around room temperature, however, slip on all known systems provides only four.' In each case, the slip direction is in the (0001) basal plane so that slip does not allow strain along the c axis. With increasing temperature, more slip occurs on the ( 1011) pyramidal plane and the ( 1010) prism plane but without change in direction.'?' Thus, that development alone cannot explain the transition temperature.

Jan 1, 1968

By Thomas Read

PERSONNEL work is a term recently introduced to cover the great variety of activities in industrial work that deal with the human factor. Much attention has been focussed upon individual phases of personnel work, such as accident prevention, sanitation, "welfare" work, reducing labor' turnover, and so on. In most cases these activities have been carried on as though they were distinct and separate fields; as a matter of fact, they are only different phases of the single problem of human engineering, and each has important and fundamental relations with the others. Thus, for example, high labor turnover is one of the most .important causes of a high accident rate, and unsatisfactory housing conditions are an important cause of labor turnover. In the early stages of the study of these problems, it was necessary to take them up separately; the time has now arrived at which it is desirable to consider them as a whole in order to bring them into the right relation to each other. When thus considered as phases of an interrelated whole, they may be grouped as personnel work. A discussion of the importance of personnel work as a means of in creasing dividends in industry may be objected to by some as a too materialistic way of looking upon work that is humanitarian. Nothing could he more mistaken than such an opinion. Humanitarianism, per se, has no place in industry, and nothing is gained and much is lost in pre tending that it has. The only reason why a corporation engages in business is to make profits, and any activity of the corporation that does not tend either directly or indirectly toward that end is poor business. It is equally poor business to overlook any activities that do tend indirectly to the making of profits. On this basis, personnel work can be justified as a corporate activity; there is no justification whatever for abstract humanitarianism from the business standpoint. One characteristic of the American workman is a general high level of intelligence, and it is an insult to intelligence to ask a man to believe that anything so impersonal as a corporation is really desirous of benefiting

Jan 10, 1917

By C. E. Arnold

A brief description of this installation was included in a recent paper by H. Kenyon Burch.l The purpose of the present paper is to amplify Mr. Burch's description, as it is felt by the writer that the subject merits more than passing attention. In making a comparison between the common method of hoisting men in mine shafts, and elevator practice in high buildings, the former shows to great disadvantage both as regards safety measures and smoothness of operation. It is surprising that in view of the inducements offered, the step of applying the building equipment direct to the mine shaft has not been taken before, as in many respects the conditions of service are similar, and the objects to be attained are identical. Even without doing this, it is certain that safety to life and limb in the usual method of hoisting men underground can be greatly enhanced by the application to the mine hoist of some of the features of the building elevator. In the case under consideration, the elevator cage runs in a vertical, concrete-lined shaft compartment 5 ft. 11 in. by 5 ft. 6 in. (1.8 by 1.68 m.) in section and 585 ft. (178 m.) deep, while the counterweight runs in the pipe and ladder compartment of a twin shaft 102 ft. (31 m.) distant. The section of the division of this compartment occupied by the counterweight measures 2 ft. 4 1/4 in. by 3 ft. 101/2 in. (0.72 by 1.18 m.), and the counterweight is made in the form of a small cage which suffices to carry two men for the purpose of making inspections or repairs in the pipe and ladder way. The hoist is designed to carry a load of 7500 lb. (3401.94 kg.), ex-clusive of the cage, which weighs 7500 lb., at a maximum speed of 800 ft. (243 m.) per minute. It is installed in the main hoist and compressor building about 220 ft. away from the elevator shaft and is driven by a 160-hp. direct-current motor which is served by a 190-hp. motor generator set. A small direct-current generator mounted at the end of the motor generator set furnishes the current for the controller magnets, brake and fields of the hoist motor and generator. The drum, which is 72 in. (1.83 m.) in diameter, is driven through the medium of a single reduction herringbone gear. A Francke flexible coupling connects the

Jan 1, 1918

By Don B. Shupe, John K. Berry

The handling and disposal of mine water is a much larger problem than is apparent at first glance. Many more tons of water are removed from underground coal mines in the United States each year than tons of coal. In the old anthracite region of Pennsylvania the average was around 32.7 t (36 st) of water for each ton of coal produced, while bituminous mines average about 4.5 or 5.4 t (5 or 6 st). Water encountered in the mines may come from several different sources. In mines with light cover and without a firm solid roof, rain may seep directly into the workings. This is also true of deeper mines where pillar falls have broken the roof to the surface. The top under creek beds is generally faulty and broken and water comes through the roof at this point. Deeper mines are frequently overlain by water-bearing strata and pillar breaks and faulty top can admit water, while places running to the dip often accumulate water which comes up through the bottom. In all cases, except where passing under a year-round stream, the amount of water made is usually pretty closely connected with the weather-more water during the rainy season, less in the dry, although the deeper a nine is, the longer it is before changes in rainfall are felt. Another source of water, not connected with seasonal changes, is old water, accumulated over a period of time in abandoned workings of the mine, or from flooded adjacent mines. Here the water filters through the coal, the parting, or comes up through cracks in the bottom. Similarly, core holes, drilled to prospect the property, can be a source of unexpected water and modern safety requirements for dust-allaying water at the working faces can turn a pleasant working area into a soggy mess over the weekend if the system is not properly maintained and operated. Why water must be disposed of is obvious. If allowed to accumulate, sooner or later the mine will fill up, or at least it will become "roofed" in low places, blocking ventilation and traffic. It must be controlled long before it reaches this stage. Water standing in the working faces is

Jan 1, 1981

By Don B. Shupe, John K. Berry

The handling and disposal of mine water is a much larger problem than is apparent at first glance. Many more tons of water are removed from underground coal mines in the United States each year than tons of coal. In the old anthracite region of Pennsylvania the average was around 32.7 t (36 st) of water for each ton of coal produced, while bituminous mines average about 4.5 or 5.4 t (5 or 6 st). Water encountered in the mines may come from several different sources. In mines with light cover and without a firm solid roof, rain may seep directly into the workings. This is also true of deeper mines where pillar falls have broken the roof to the surface. The top under creek beds is generally faulty and broken and water comes through the roof at this point. Deeper mines are frequently overlain by water-bearing strata and pillar breaks and faulty top can admit water, while places running to the dip often accumulate water which comes up through the bottom. In all cases, except where passing under a year-round stream, the amount of water made is usually pretty closely connected with the weather-more water during the rainy season, less in the dry, although the deeper a mine is, the longer it is before changes in rainfall are felt. Another source of water, not connected with seasonal changes, is old water, accumulated over a period of time in abandoned workings of the mine, or from flooded adjacent mines. Here the water filters through the coal, the parting, or comes up through cracks in the bottom. Similarly, core holes, drilled to prospect the property, can be a source of unexpected water and modern safety requirements for dust-allaying water at the working faces can turn a pleasant working area into a soggy mess over the weekend if the system is not properly maintained and operated. Why water must be disposed of is obvious. If allowed to accumulate, sooner or later the mine will fill up, or at least it will become "roofed" in low places, blocking ventilation and traffic. It must be controlled long before it reaches this stage. Water standing in the working faces is

Jan 1, 1981

By C. A. Fothergill

An improved blotter model is described which makes use of a plastic sheet as base for the blotter field and pins to represent the input wells. The model is simple to construct and adapt and is particularly useful for demonstration purposes. Operational details are given. INTRODUCTION The blotter model was first applied to the investigation of oilfield problems by Wyckoff, Botset and Mus-kat,' primarily in order to demonstrate the flood patterns which could be expected from various arrangements of input and output wells in waterflooding projects. In recent years the model has been largely superseded for analog studies by the potentiometric and electric analog models which are more refined and versatile, since they can simulate the form, and, in certain cases, permeability variations which it is not possible to do with the blotter model. However, the latter is still used for analog studies where the reservoir can be represented as being uniform in thickness and permeability, and where a visual record of the flood advance is required. Ramey andNabor,2 for example, have applied the model to the investigation of areal sweeps in oil recovery by in-situ combustion. Because of its limitations, the blotter model can be used in general for only very simple arrangements of input and output wells, but within these limitations it has a definite advantage over all other types, in that it provides a picture of the advancing flood using the simplest and most easily constructed apparatus, by contrast with the gelatin model, for example, which requires more elaborate equipment. Moreover, the experiments can be quickly repeated and modified if necessary, whereas considerable time is required to prepare a gel field, compared with that required for the preparation of sheets of conducting blotting paper. For these reasons the blotter model can be very useful for demonstration and teaching purposes, enabling the student to experiment for himself with different arrangements of input and output wells. A model has been constructed for this purpose which is simple to operate and adapt. The model (Fig. 1) consists of a base platform or box, approximately 12-in. square, on top of which are screwed three lathes of 1/2 -in. square section to form three sides of a square 6 in. in length. This forms the support for a sheet of Cobex, transparent plastic, thickness .003 in., on which is carried the blotting paper representing the field. The plastic is flexible and relatively soft, and can be attached to the support by cellulose tape so that it can be easily removed when required. The input wells are represented by brass drawing pins pressed through the plastic sheet from the underside until the points are just projecting through the top; these are connected in the circuit as shown in Fig. 2. The sheet of blotting paper of required shape and size is saturated with a solution of 0.2 n-potassium sulfate to which has been added a saturated alcohol solution of phenol-phthalein at a strength of 10 cc/liter of stock solution. The surplus water is removed and the blotting paper placed in position on the plastic sheet making contact with the drawing pins and the sheet (which is an insulator). The anode consists of a second sheet of blotting paper cut as shown and saturated with the same solution. This is suspended from a laboratory stand, being connected to the conducting wire by means of a crocodile clip and making contact with the horizontal blotting paper at the projecting point. This is the method used by Ramey and Nabor and which permits the hydroxyl ions or colored front to reach the anode. As shown in Fig. 2, the electrical voltage used is 220-v DC and a shunt is placed across the terminals to step down the voltage as required. Further adjustment can be made as necessary using a lamp board in series with the shunt to obtain the

Jan 1, 1958