Search Documents

By R. Wang, N. J. Grant, B. C. Giessen

By crystallographic and X-ray methods, the existence and isonzorphism of Ti3Rh5 and Hf3Rhs were confirmed. Both phases are of the orthorhombic Ge3Rh5 type; lattice parameters and refined positional parameters are given. The structure is related both to the filled-up NiAs-B8 and Cu-AI types. An analogous phase with zirconium does not exist; the effect of ternary substitutions for titanium ad hafnium suggests a size factor limit to be active. A recent survey of phase diagrams of the T4 metals titanium, zirconium, and hafnium with the T, noble metals rhodium and iridium indicated the existence of the A3B5 phases Ti3Rhs, ZrsRhs, and HfsRhs. Ti3Rhs and Hf3Rh5 were found to be isostructural, based on the line-rich powder patterns which had not been analyzed. Zr3Rh5 was considered to have a substructure of the NbRu type (orthorhombically distorted B2-CsCl type).&apos; Because, in combinations with other transition metals, hafnium and zirconium are generally more likely to form isostructural phases than hafnium and titanium (with the significant exception of the Ti2Ni-"E93" type phases based on T4 metals2), the reversal of this relation for the A3B5 phases was of interest. As shown in the following, the nonexistence of Zr3Rhs has been established, the structures of Ti3Rh5 and Hf3Rh5 have been worked out, and crystal chemical relationships and stability criteria are reported. EXPERIMENTAL METHODS AND RESULTS Alloy Preparation and Phase Diagram Work. Alloys were prepared from high-purity (99.99+ pct) elements by arc-meltin3,4.Heat-treated alloys were annealed in a vacuum of 3 x X torr for 24 hr at 1300DC. Metal-lographic samples were etched electrolytically in concentrated HCl with 5 v ac for 5 min.3 X-ray diffraction powder patterns were taken on a GE XRD-5 dif-fractometer with Cum radiation at low scanning rates (0.2 deg per min for 28). It was confirmed that Ti3Rhs and Hf3Rh5 have similar diffraction patterns, and that an alloy with the composition Zr3Rhs has a different pattern. Six Zr-Fh alloys with 59 to 69 at. pct Rh were therefore prepared and investigated in the as-cast state by X-ray diffraction and metallography. Alloys at 59 and 61 at. pct Rh were found to be a single phase, with the distorted B2-CsC1 type structure typical for the off-stoichio- metric region of the phase (Zr,-,Rh,)Rh. This phase forms a eutectic with ZrRhs at about 66 at. pct Rh: accordingly, alloys between 61 and 69 pct at. pct Rh consisted of two phases. There is no evidence for the existence of Zr3Rh5. Based on the results in Rafs. 1 and 5, on the present work on Zr-Rh, and on several additional alloys investigated, the portions between the AB and AB3 stoi-chiometry for Ti-Rh, Zr-Rh, and Hf-Rh are as follows: Further, several ternary alloys near Ti3Rhs and Hf,Rhs were prepared in which it was attempted to replace titanium and hafnium partly by zirconium, niobium, tantalum, and germanium. The results will be discussed in a later section. Structure Determination of Ti3Rh5. Since Ti3Rh5 and Hf3Rh5 are isostructural, the following discussion will largely deal with the former. Although the powder pattern of TisRhs is complex, as found previously,1 it could be indexed by comparison with other structures of A3Bs stoichiometry. Ti3Rh5 was found to be isostructural with Ge3Rh5, whose orthorhombic structure had been elucidated by Geller.9 As both the sizes and atomic numbers of germanium and titanium are comparable, the unit cell volume and the peak intensities could be expected to be similar; however, significant differences exist in the atomic positions, as will be shown. All lines in the powder patterns of Ti3Rh5 and Hf3Rhj could be indexed with primitive orthorhombic unit cells with the lattice constants: The fractional errors are 10 The low-angle portion of the indexed powder pattern of Ti3Rh with sin2 8 < 0.30 is listed in Table I. The extinction laws Okl only with k = 2n and hOl only with h - 2n are compatible with the space group Pbo2 and the more symmetrical space group Phnm of Ge3Rh5. Finally, the positional parameters of Ti3Rh5 and HfsRhs were refined under the assumption that titanium and hafnium occupy the germanium positions in Ge3Rh5. Integrated intensities were obtained from the diffraction patterns by planimetry. Intensities of overlapping reflections were separated by an iteration process incorporated into the least-squares positional refinement program according to a method described previously. The intensities of Ge3Rh5 were used in the first separation cycle, while the atomic parameters of Ge3Rh5 were used as starting values in the first refinement cycle. Absorption due to specimen

Jan 1, 1970

By C. B. Murray

"OUR experience from time immemorial has been that the furnace sampler and analyst usually find one or two, and sometimes more, points less iron than the Lake Superior shippers, but, fortunately, their contracts are `iron bound&apos;; and, generally speaking, analyses at this end are practically useless, for we are obliged to settle on basis figured out to a half dozen decimals, and, as a rule, without recourse in the event of flagrant discrepancies between the two analysts." The above is an extract from a letter received by the writer of this paper from the President of an iron company, discussing the question of sampling. It so well expresses the opinion of many blast-furnace owners and managers that it seems a suitable text for a discussion concerning the need of uniform methods of sampling. If all railroad cars were loaded the same, if all stock piles were the same shape, and if ore was received regularly each day, the problem of sampling would be comparatively simple. The conditions, however, vary widely at different places, and at the same place from day to day, and it is probably impossible to determine upon any one method of sampling which will apply at all times and in all cases. However, it would seem as though some general principles might be suggested which would tend to overcome these wide differences in samples of the same thing. The sampling of a cargo of iron ore begins at the breast of ore in the mine. The ore is sampled from the mine cars, from the stock piles, and from the railroad cars at the mines. At the lower Lake ports the ore is practically all sampled from the boat, occasionally from railroad cars. At the furnaces, the ore is nearly all sampled from railroad cars and occasionally from stock piles.

Jan 1, 1914

By M. P. Tixier, A. Poupon, M. E. Loy

Simple qualitative methods are explained for identifying those shaly sands in a well that are most likely to contain oil. A need for more precise measurement of the variables that enter shaly sand analysis is indicated. Field examples are given to illustrate the methods. A theoretical discussion of the quantitative interpretation of shaly sands is given as a basis for discussion and as a guide for the future. While not generally capable of practical application at the present time because of the lack of sufficient accuracy of the electric log data, these methods may become more feasible in the future as the result of the improved logging methods now being introduced. INTRODUCTION Experience has shown that for porous formations containing only a negligible amount of clayey material, reliable information on the fluid saturation and porosity of the reservoir rocks can usually be derived from the electrical logs. The interpretation is based on empirical formulae relating the true resistivity of a porous formation to its lithologic character, to the resistivity of the interstitial water, and to the proportions of water and hydrocarbons in the pores.&apos; If the resistivity of the interstitial water is not known, its approximate value can be derived from the SP curve.2,3 The porosity can usually be determined to a good approximation from a MicroLog, or a MicroLaterolog.4,5 When the reservoir rocks contain an appreciable percentage of clayey material, an additional factor is introduced into the analysis. In a clean formation, the matrix is an electrical insulator, so that the ability of the formation to conduct current is due only to the conductivity of the electrolytes in the pores; in a shaly formation, the shale constitutes a part of the rock matrix able to conduct current, and influences the resistivity of the formation. On the other hand, the spontaneous emf&apos;s and the circulation of the SP currents are also responsive to the presence of the shaly material. All other factors being the same, the deflection of the SP curve opposite a shaly permeable formation is smaller than the deflection which would be observed if the formation were clean. The effects of the presence of shale on the resistivity and on the SP curves in a shaly formation are functions of the amount, of the specific resistivity, and of the geometrical distribution of the shaly material within the formation. The presence of shale therefore constitutes an important complication in electrical log interpretation. It is easy to realize, for example, that the presence of a large amount of clayey material in a sand may have such a predominant effect that the resistivity of the sand will not change very much, whether the pores are entirely filled with connate water, or contain a high saturation of hydrocarbons. Important research projects have been undertaken to investigate the influence of shales and to find a way to allow for this influence in the interpretation of a log. The problem of the SP in shaly sands was analyzed mathematically by H. G. Doll"&apos; for the case of sands with shale laminations. Formulae expressing the resistivity of shaly formations were proposed by Patnode and Wyllie8 and de Witte.9 Other quite interesting theoretical and experimental results have been published by various authors.l0,ll,12,l3,14 The purpose of the present paper is to discuss an approach to electrical log interpretation in shaly sands. This approach is based partly on some of the theoretical and experimental data available in the literature and partly on observations made on actual field logs. Comparatively simple methods for qualitative and semi-quantitative analysis are described. These methods depend principally upon information provided by the electrical logs.

Jan 1, 1955

By Laurance Reid

HIGH compression ratios, resulting from high injection pressures and relatively low recovery process pressures, constitute a major problem, which has confronted those engaged in gas recycling for condensate production since the beginning of that practice. Despite the numerous process developments and improvements, no entirely satisfactory solution for this prob-lem has been presented to date. Often, where the residue gas from the recovery process must be recompressed for subsurface injection, there is a substantial difference between the required injection pressure and the plant-operating pressure required to produce maximum recovery of condensate. These limitations result in high compression ratios, which, in turn, neces-sitate excessive compressor investment and operating cost. As an alternative, the operating pressure may be increased in order to lessen the compressor requirements but such a saving often is purchased at the expense of decreased condensate recovery, caused by operation at the higher pressure. Regardless of the choice, the net result is a diminished return on the capital invested in the project. The goal of future development in this field must be the complete recovery of all valuable hydrocarbon components in the reservoir fluid at pressures that, regarded as compressor suction pressure, will require minimum compressor horsepower to inject the residue gas into the formation. A com-pression ratio of 1.5 has been established as an optimum for modern compressor equipment." Therefore, in order to con-form to this optimum condition, a 3000-lb. injection pressure would require that the condensate recovery process be operated at 2000 lb. per sq. inch.

Jan 1, 1940

By A. C. Bulnes

This paper applies the methods of statistical analysis to the interpretation of core analysis data of dolomitic limestone from the San Andres formation at Wasson and the Clearfork formation at Fullerton. Probability relationships are shown to connect the porosity and the permeability and the porosity and the fluid saturation. For example, the porosity-permeability relationship expresses the probability that a sample of porosity,f, will or will not be permeable. The over-all porosity frequency distribution of the reservoir together with the frequency curves of permeability (one for each class interval of porosity) provide a precise basis for computing the weighted average productive porosity of the reservoir for any assigned value of the minimum productive permeability. The probability that the permeability of a core specimen from Fullerton will exceed a given value appears to be dependent on the percentage porosity of the specimen, its void structure type (i.e., porosity in the qualitative sense), and the given value of the permeability. If continuous profiles of void structure type and porosity are available together with the appropriate porosity-probability of permability plots, the nes pay thickness may be estimated. The Invasion Index of a well is defined in terms of the porosity and permeability data. This index is suggested as a basis for comparing wells as regards their suitability as fluid-injection wells. Three problems of importance in the exploitation of limestone reservoirs may be stated as follows: 1. The determination of the productive porosity of the reservoir. The productive porosity is defined as f = fPVP/V [II in which Vp, is the volume of the reservoir that is sufficiently permeable to oil to give up an appreciable fraction of its original oil in place during the economic life of the reservoir; fp, is the arithmetic mean porosity of the permeable volume v*, and V is the total volume of the reservoir. 2. The determination of the number of feet of oil-bearing porous rock that will produce at a commercial rate into the well bore; i.e., the net pay thickness. 3. The choice of fluid-injection wells in a secondary recovery program. The ultimate recovery of the reservoir is proportiona1 to the productive porosity. The productive capacity of the well is proportional to the net pay thickness. The principal purpose of this paper is to show that the methods of statistical analysis when applied to core analysis data of dolomitic limestones offer a useful approach to the solution of these three problems, as well as others of importance in reservoir engineering. The use of these methods was suggested by the work of Jan Law.1

Jan 1, 1946

By A. C. Bulnes

This paper applies the methods of statistical analysis to the interpretation of core analysis data of dolomitic limestone from the San Andres formation at Wasson and the Clearfork formation at Fullerton. Probability relationships are shown to connect the porosity and the permeability and the porosity and the fluid saturation. For example, the porosity-permeability relationship expresses the probability that a sample of porosity,f, will or will not be permeable. The over-all porosity frequency distribution of the reservoir together with the frequency curves of permeability (one for each class interval of porosity) provide a precise basis for computing the weighted average productive porosity of the reservoir for any assigned value of the minimum productive permeability. The probability that the permeability of a core specimen from Fullerton will exceed a given value appears to be dependent on the percentage porosity of the specimen, its void structure type (i.e., porosity in the qualitative sense), and the given value of the permeability. If continuous profiles of void structure type and porosity are available together with the appropriate porosity-probability of permability plots, the nes pay thickness may be estimated. The Invasion Index of a well is defined in terms of the porosity and permeability data. This index is suggested as a basis for comparing wells as regards their suitability as fluid-injection wells. Three problems of importance in the exploitation of limestone reservoirs may be stated as follows: 1. The determination of the productive porosity of the reservoir. The productive porosity is defined as f = fPVP/V [II in which Vp, is the volume of the reservoir that is sufficiently permeable to oil to give up an appreciable fraction of its original oil in place during the economic life of the reservoir; fp, is the arithmetic mean porosity of the permeable volume v*, and V is the total volume of the reservoir. 2. The determination of the number of feet of oil-bearing porous rock that will produce at a commercial rate into the well bore; i.e., the net pay thickness. 3. The choice of fluid-injection wells in a secondary recovery program. The ultimate recovery of the reservoir is proportiona1 to the productive porosity. The productive capacity of the well is proportional to the net pay thickness. The principal purpose of this paper is to show that the methods of statistical analysis when applied to core analysis data of dolomitic limestones offer a useful approach to the solution of these three problems, as well as others of importance in reservoir engineering. The use of these methods was suggested by the work of Jan Law.1

Jan 1, 1946

By AIME AIME

MORE than thirty members of the Coal Division attended the Coal Land Valuations Round Table on Monday morning. Chairman Dilworth stated that the Committee had been appointed to take up the question and, after reading the list of members of the Committee, pointed out that the object of the meeting was to formulate a plan of action rather than to discuss any phases of valuation, per se. To this end he presented a tentative outline of points to be considered in the future by the Committee. After a lively discussion on the desirability of inclusion of some questions in the agenda of the Committee, the following outline was adopted :

Jan 1, 1931

By Jun-Yan Chen

Ground control problems in sublevel caving become evident as the rock pressure increases with depth. Recently, a finite element analysis of the stability problem of the sublevel caving method was completed by the author. This paper summarizes the results of stress analysis in sublevel extraction drifts under different field stress conditions by using linear elastic and nonlinear elastic-plastic finite element modeling techniques. A critical stress concentration will occur in the uppermost sublevel drifts beneath the caved area or blasted ore area. During the blasting and drawing cycle, a tensile and shear failure condition could develop in the center extraction drift when it would be mined last. Under a high horizontal stress field condition, almost all tensile stress in the back of the extraction drifts will be eliminated and only slight yield can be seen in the floor of the extraction drifts. Compared to the cases under the stress field where vertical stress is the dominant factor, the total yielding zone will be greatly reduced because of an in- creasing horizontal stress field with depth. However, it is predicted that the center of each ore column side will experience excessive shear stress that probably will result in ore failure. The two major conclusions drawn from this study to improve the overall stability of sublevel caving are: (1) the drift width must be carefully controlled and an appropriate stoping sequence selected; and (2) the sublevel caving method can be used in deep min

Jan 1, 1983

By E. H. Tenney

A discussion of the probable future use of coal for power development involves the study of several basic factors, such as future demand for power, the quantity and availability of fuels in direct competition with coal, the price of coal, and a closely related factor—the efficiency and cost of fuel utilization. Predictions based on purely statistical analyses of past coal consumption have definite limitations. For example, statistics showing the relation between coal utilization and total energy consumption from all sources between the years 1890 to 1930 indicate that during that period the energy consumption per person in the United States increased five times, while the coal consumption per person increased only twice1, and there has been an actual decrease in per capita coal consumption since 1920. Figures such as these, compiled by authentic agencies, emphasize the need for caution in attempting estimates as to the future use of coal, and, incidentally, would seem to offer little basis for optimism in the coal industry. They also suggest the value of analyzing broadly the part played in the past by the related factors of power consumption, competitive fuels, coal prices and the efficiency of utilization. Proper weight must also be given in such a study to the present status and limitations of power-plant developments, arid to the question of what the coal industry itself can do to further its own interests arid influence the consumption of its product.

Jan 1, 1936

By E. H. Tenney

A discussion of the probable future use of coal for power development involves the study of several basic factors, such as future demand for power, the quantity and availability of fuels in direct competition with coal, the price of coal, and a closely related factor—the efficiency and cost of fuel utilization. Predictions based on purely statistical analyses of past coal consumption have definite limitations. For example, statistics showing the relation between coal utilization and total energy consumption from all sources between the years 1890 to 1930 indicate that during that period the energy consumption per person in the United States increased five times, while the coal consumption per person increased only twice1, and there has been an actual decrease in per capita coal consumption since 1920. Figures such as these, compiled by authentic agencies, emphasize the need for caution in attempting estimates as to the future use of coal, and, incidentally, would seem to offer little basis for optimism in the coal industry. They also suggest the value of analyzing broadly the part played in the past by the related factors of power consumption, competitive fuels, coal prices and the efficiency of utilization. Proper weight must also be given in such a study to the present status and limitations of power-plant developments, arid to the question of what the coal industry itself can do to further its own interests arid influence the consumption of its product.

Jan 1, 1936

By Casper A. Nelson, Wendell M. Whitecotton

A WIDE variety of lead ore is treated by the Midvale Smelter, for it is a custom plant not only treating Company lead concentrate and direct-smelting ores but also custom ores and concentrates, principally from Utah, Idaho, and Nevada, with lesser amounts from Arizona, California, Colorado, Montana, Oregon, and Washington. The principal operating departments of the plant are weighing and sampling, Wedge roaster, D&L sintering, blast furnace and drossing, and baghouse. The lead bullion produced is shipped to a subsidiary, the U.S.S. Lead Refinery, Inc., at East Chicago, while the by-products, such as matte and speiss, are shipped to other smelters or re-treated at the plant.

Jan 1, 1948

By Leonard Logan

Production control in the petroleum industry may be discussed under three general heads: engineering, legal, and economic. Though the problems that fall under the respective heads of engineering, law, and economics are separate, they are dependent and interrelated. The present study will deal with the economic phases of production control and only incidentally with the legal phases as they affect the economics of the problem. No one of these forms of control is more important than the others. The engineers have performed their service well, and although there are many problems of engineering control yet to be solved, they are not pressing. Legal control is a problem for the legislatures and the courts to solve. The petroleum industry is such a comparatively young industry and the legal problems are of such recent origin that the courts have not yet been called on to settle all the issues and the legislatures still have before them bills concerned with the regulation of the industry. Economic control of production in the petroleum industry is a highly desirable goal but it has not yet been completely achieved. Since the first commercial well was drilled in 1859, there have been recurring periods of overproduction. (Over- production will be used here to describe a condition wherein so much crude oil is available that a satisfactory and reasonable price is not received for the product.) The production of oil in 1859 approximated only 2000 barrels. In the following year production jumped to 500,000 barrels, thus bringing into

Jan 1, 1932

By D. K. Atwood

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

Jan 1, 1965

By N. E. Norman, R. Stier

The mining industry is continually seeking out new and better underground mining techniques. One of the most recent-also, perhaps, the most significant-of the new concepts in underground mining is the use of mechanical rock-boring machines. And one of the problems that concerns us all in this matter is the cost of mechanical rock tunneling. To help answer the oft-quoted question "What will it cost me?" the following pages deal with the operating costs of so-called "medium to medium hard rock" boring machines-i.e., those designed to meet the drilling requirements in 8000 psi to 25,000 psi rock. A few machines are capable of drilling hard rock above 25,000 psi, but the economics of mechanical tunneling in rock that hard is limited at the present time. [ ] For mechanical rock tunneling, there are five main cost factors influencing the expense: Capital Investment, Cutters, Labor, Power Requirements, and Maintenance. These factors give us a good basic picture of the cost of excavation, although muck handling, erecting supports, and other costs directly related to conventional tunneling and mechanical boring enter into the final picture.

Jan 6, 1967

By W. F. Guenther

The usual hand-operated drilling outfit consists of a 4-in. post-hole auger with 3/4,-in. pipe for drill stem, in 4-ft lengths, with a turning handle fitted to a top pipe T. The auxiliary tools are: a chisel-bit drill made from 3/4 or 7/8-in. tool steel welded to a 4-ft length of 3/4-in, pipe, so that the regular pipe string can be used; also a churn or "mule foot" made from 3-in. pipe, slotted on one side, belled to a 4-in. tempered cutting edge on the bottom, all welded to a 3/4-in. coupling by a yoke. Other tools required are pipe wrenches and cleanout tools made from old auto springs (Fig I). A 4 1/2 or 5-in. collar welded to a plate is often used to protect the mouth of the drill hole. In general the auger is used in the typical clay overburden and brown phosphate matrix, which is relatively soft. The churn or "mule foot1&apos; is used in hard pan, lump phosphate or cherty ground. The drill is used for breaking flint, often found loose in the overburden. The drill with the chisel bit is used for trimming sides of the hole, sounding for lime bottom and breaking through hard lumps. Holes have been drilled to a depth of 80 ft, but the limit of efficient operation is about 50 ft. In deep holes it is necessary to unscrew the string in 20-ft lengths, to

Jan 1, 1948

By W. F. Guenther

The usual hand-operated drilling outfit consists of a 4-in. post-hole auger with 3/4,-in. pipe for drill stem, in 4-ft lengths, with a turning handle fitted to a top pipe T. The auxiliary tools are: a chisel-bit drill made from 3/4 or 7/8-in. tool steel welded to a 4-ft length of 3/4-in, pipe, so that the regular pipe string can be used; also a churn or "mule foot" made from 3-in. pipe, slotted on one side, belled to a 4-in. tempered cutting edge on the bottom, all welded to a 3/4-in. coupling by a yoke. Other tools required are pipe wrenches and cleanout tools made from old auto springs (Fig I). A 4 1/2 or 5-in. collar welded to a plate is often used to protect the mouth of the drill hole. In general the auger is used in the typical clay overburden and brown phosphate matrix, which is relatively soft. The churn or "mule foot1&apos; is used in hard pan, lump phosphate or cherty ground. The drill is used for breaking flint, often found loose in the overburden. The drill with the chisel bit is used for trimming sides of the hole, sounding for lime bottom and breaking through hard lumps. Holes have been drilled to a depth of 80 ft, but the limit of efficient operation is about 50 ft. In deep holes it is necessary to unscrew the string in 20-ft lengths, to

Jan 1, 1948

By Robert Goodwin, Frank R. Milliken

IN September 1939, the Ohio Copper Co. inaugurated the treatment of its copper-bearing mill tailings at Lark, Utah. These tailings had been accumulated during the regular operation of the Ohio Copper mine and mill over the period 1907 to 1919. Gravity concentration had been employed except for a comparatively short period in 1919, when flotation was used. The ore milled during that period assayed about 1 per cent Cu. The chief copper mineral, chalcocite, was disseminated in a shattered quartzite, mainly along fracture or cleavage planes. The quartzite gangue was extremely hard and grinding to liberation resulted in excessive sliming of the "sooty" chalcocite, with consequent high tailings losses. Recovery on the seven million tons treated was probably less than 6o per cent of the total copper content. As early as 1918, attempts had been made to sample the dump. In 1928, a complete sampling program was undertaken. The sampling consisted of seventy-four 5-in. post auger holes drilled to the full depth of the dump at regular intervals of 250 ft. Each 10-ft. portion thereof comprised a sample for analysis. Each sample was screened, rolled, divided into three parts, dried and assayed. The reject was retained for testing purposes. From the depth of the auger holes a contour map of the dump was plotted, Fig.1, which gives percentages of tonnage and copper content. The tonnage within the limit of the drill holes was estimated at about five million tons with an average content of 0.42 per cent Cu, 31 per cent of which (0.13 per cent) was acid-soluble. A screen analysis of the composite dump sample is shown in Table I. Flotation tests by several companies and individuals were then made, the results of [ ] which ranged from 62 to 74 per cent recovery. On the basis of these, a Zoo-ton pilot plant employing straight flotation was built and operated for a few months. Operation of this plant was unsuccessful, as no provision had been made to handle the copper-bearing solutions resulting from the water-soluble copper, a point that was overlooked in the laboratory test work. Attempts to decant the copper-bearing solution for precipitation in the usual manner ahead of flotation were not satisfactory because of low water recovery (owing to poor settling characteristics of the pulp) and contamination of the copper precipitate with unsettled slime. Low copper prices in 1931 necessitated the termination of testing. With the stimulus of higher copper prices in 1937, a review was made of metallurgical

Jan 1, 1940

By Bruce W. Gonser, Robert J. Nekervis

EACH metal has a unique combination of properties that distinguishes it from other metal;. Su& a combination may account for applications that cannot be met very well by anything else. This is particularly true of tin, one of the earliest metals used by man. Table i shows the consumption of tin in the United States by usage for the years 1949 and 1950, which may be considered to be generally typical of current usage. The major applications-tinplate, solders, bronze, and babbitt-were well established a century ago. Applications for the metal and (probably later) of tin alloys started more than 5000 years ago. Fortunately for the ancients, tin is one of the metals whose oxide is easily reduced by carbon. Nature further simplified the refining problem by providing only one ore of commercial importance, cassiterite (SnO2). Tin is easily reduced from cassiterite. All that is necessary is high heat in the presence of carbon. It is quite possible that back in the dawn of history, tin was discovered when black alluvial sand was thrown on a fire, either to bank it or to put it out. SOURCES OF TIN All the important tin-producing centers are in the southern hemisphere, far away from the&apos; industrial consuming centers. Fig 1 shows their location and 1950 production. Reserves are adequate, and the industry is able to produce considerably more tin than is

Jan 1, 1953

SEC. 1. The membership of the Institute shall comprise seven classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6. Rocky Mountain Members; 7. Junior Foreign Affiliates. All shall be equally entitled to the privileges of membership, excepting that no member of any class whose residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the. class of Member must be at least 27 years of age and must have had at least six years&apos; employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members. SEC. 3. Honorary Members: Each candidate for Honorary Membership must be recommended by at least ten Members and must be elected by ballot at a meeting of the Board of Directors by the unanimous vote of the Directors present; provided, however, that the number of Honorary Members shall at no time exceed twenty. Such election shall automatically act as a transfer of such member from any other class of membership to which he may belong. SEC. 4. Senior Members: The Directors may, at the special request of any Member or Associate who has reached the age of seventy years and who has paid dues for thirty years, transfer such Member or Associate to the class of Senior Member; and in special cases may waive either the requirement as to age or as to the number of years for which dues have been paid. SEC. 5. Junior Members: A person to be eligible for election to the class of Junior Member must be qualified -through education or experience to hold a subordinate position in engineering, mining, metallurgical, geological or chemical work. He shall be not more than 33 years of age at the time of election. .SEC. 8. Associates: A person eligible for election or transfer into the class of Associate shall be one, who, in the opinion of the Committee on Admissions and the Board of Directors, is suitable for such election or transfer by reason of his interest in or connection with mining, geology, metallurgy, or chemistry. SEC. 7. Rocky Mountain Members: Membership in a special class of life memberships without annual or other dues and without right to receive the printed literature distributed to other members or the right and privilege of wearing the official badge of technical members, is given to all members of the Rocky Mountain Club at the time of consolidation. These special Rocky Mountain memberships shall be claimable by any member of the Rocky Mountain Club, not already a member of the Institute, availing himself of the privilege within ninety days after mailing of notice to him, by the Secretary of the Institute. SEC. 8. Junior Foreign Affiliate: Upon appropriate action by the Board of Directors and with its approval, members in good standing of any technical society having its headquarters outside of the United States of America, Canada, or Mexico,

Jan 1, 1940

By Eugene McAuliffe

The mining press, as well as certain federal and state bulletins, refer from time to time to the relative hazards that attach to loading bituminous coal by hand when compared with the so-called "mechanical loading" process. Much of the coal coming under the head of hand-loaded coal is won in part by the use of machinery; the coal-cutting machine is in general use, the electric power drill employed to a lesser extent. Therefore it may be said that the principal difference in the process employed, mechanical loading versus hand loading, lies in the fact that some type of loading machine is employed in the mechanical loading process to lift the coal from the face of the room, place or entry, after it is mined, placing it in the pit cars for transport to the tipple. It is a common practice to compute accident records on the basis of tons mined per fatal and per nonfatal accident, disregarding the fact that it is possible to produce by the aid of coal-loading machines the same daily, monthly and annual tonnage with a much smaller force than is required where the coal is all shoveled by hand. Inasmuch as the men who are released by the substitution of machinery for hand labor must find employment elsewhere, suffering some measure of hazard in their new occupation, we are of the opinion that the true relative hazard that attaches to the processes of mechanical loading and hand loading can be determined only by using as the basis of comparison "man shifts worked" or "hours of exposure" experienced per accident. The Union Pacific Coal-Co., beginning with the year 1929, undertook to maintain a true record of man shifts worked per compensable accident, giving equal weight to fatal and nonfatal accidents. Accidents lacking sufficient severity to come under the compensable terms of the Workmen&apos;s Compensation Act were not included in the compilation, the Act providing that "no compensation, except the expense of medical attention, shall be allowed for the first seven (7) days of disability, unless the incapacity runs beyond the period of twenty-one (21) days, in which case the compensation shall run from the time of the injury." With the further thought that all accidents suffered by employees engaged in any service, in or about the place where the loading process

Jan 1, 1931