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By R. G. Knickerbocker

A STURDY and consistent expansion of the metal industry occurred in 1947 exemplified by an increase of approximately 30 per cent in steel consumption over 1946. For this major reason, ferroalloy metals have seen their most useful and important peace-time year. The current domestic rate of consumption of high-grade ferroalloy ores, together with added consumption of new foreign producers as well as for eign nationals' restrictions on high-grade exports, makes very evident the increasing difficulties of obtaining sufficient high-grade ores. This accentuates the need for new and less expensive methods of production of ferro-alloy metals of higher purity from lower-grade domestic resources. As an important factor in preparedness, procurement of these high-grade, -critical ferroalloy minerals and metals for our nation's stock piles is a most important task. Also, this stock-piling can be the means of supplying incentive for the industrial development of the new metallurgical processes and plants necessary for the recovery of ferroalloy metals from our domestic low-grade deposits.

Jan 1, 1948

By T. H. Weldon, L. V. Whiton, R. R. McNaughton, J. H. Hargrave

Oxygen enriched air is being used quite extensively in the metallurgical plants of The Consolidated Mining and Smelting Co. of Canada, Limited, at Trail, B.C. The oxygen used for this purpose is a by-product from the Company's chemical plants located in the area. Most of the ore treated in the Trail metallurgical plants comes from Com-inco's Sullivan Mine at Kimberley, B.C. At Kimberley the ore is milled to produce lead and zinc concentrates which are shipped to Trail for further treatment to metal. One section of this paper deals with the use of oxygen enriched air in the suspension roasting of the zinc concentrates. In this process the concentrate is calcined for leaching preparatory to electrolytic recovery of the zinc. A second section of the paper describes the use of oxygen enriched air in operations at the lead smelter. There oxygen enriched air is used in the blast to the lead blast furnaces and in the slag fuming furnace which recovers the lead and zinc contained in lead blast furnace slag. The final section of the paper outlines the precautions necessary for the safe use of oxygen enriched air in any plant operation. The Use of Oxygen Enriched Air in the Suspension Zinc Roasters The suspension roasting of zinc concentrate developed at Trail, B.C., has been described in AIME Vol. 121, "The Electrolytic Zinc Plant of The Consolidated Mining and Smelting Company of Canada, Limited" by B. A. Stimmel, W. 11. Hannay and K. D. McBean. Since the publication of that paper, the use of oxygen enriched air in suspension roasting has been introduced as regular practice with marked advantage. The relative importance of a specific advantage may vary with changing conditions, but, in general, it may be stated that improved operation has been achieved at increased capacities. Suspension roasting is carried out at Trail in converted standard 25 ft diam Wedge roasters. The 2nd, 3rd, 4th and 5th roasting hearths have been removed and the drying hearth covered over. Drying of the concentrate is done on the drying hearth and the 1st roasting hearth. The dried concentrate, after any lump's have been broken up in a ball mill, is fed to a single burner located in the upper part of the combustion chamber. Oxygen is introduced at the burner fan along with the gases from drying, returned combustion gases from the waste heat boiler outlet and the required amount of new air. Up to 60 pct of the concentrate settles out on the 6th roasting hearth, the rest passilig out of the roaster. The product collected in the waste heat boiler is finished calcine, but the dust collected in the cyclones after the boilers is returned to the base of the combustion chamber where the sulphate is decomposed. Gases from the c'yclones go to a Cottrell precipitator. The discharges from the 7th roasting hearth and the waste heat boiler are combined with the Cottrell dust to give the finished calcine. Following small scale tests started in 1933, oxygen enriched air has been used continuously in the suspension roasting of zinc concentrate in Trail, beginning in 1937. A significant factor in promoting its use in this operation was the availability of by-product oxygen from the Company's near-by Chemical and Fertilizer Division. To-day it is standard practice at Trail to use oxygen enriched air for zinc concentrate roasting. The most important requirement in roasting a zinc concentrate for an electrolytic plant is that the zinc in the calcine should have maximum solubility. It is also desirable at Trail that the gas produced for the manufacture of suhhuric acid should have a ~naximum concentration of SO2 and that a substantial recovery of waste heat from the gas be achieved. High solubility of zinc requires that the sulphide sulphur and zinc ferrite in the calcine be kept low. These are both functions of temperature and time, with formation of zinc ferrite also dependent on contact between the iron and zinc particles. One of the inherent advantages of suspension roasting is that minimum time and contact are achieved. The limit on temperature is imposed by the fusion point of the concentrate and not by the need to control zinc ferrite formation. Operating temperatures are normally maintained within the limits of 1725" and 1850°F. A relatively low zinc sulphate in the calcine is required at Trail, and this results from discharging the calcine from the high sulphur dioxide atmosphere at a temperature above 1600°F.

Jan 1, 1950

By Lloyd Emory

THE region known as. Guyana or Guiana stretches along the north coast of South America from the mouth of the Orinoco River in Venezuela to the mouth of the Amazon River in Brazil. Politically, it is divided into British, Dutch, and French Guiana, extend¬ ing into Venezuela on the north and into Brazil on the south. Because the area is within the sweep of the northeast trade winds and of approximately the same latitude, plant' and animal life are fairly uniform throughout. The geology is very similar as far as the northern coast is concerned. The drainage is taken care of by a number of large rivers that flow northward directly into the sea. The Courantyne River, which roughly divides the area into half, is the eastern boundary of British Guiana.1 The lower reaches of this river are also the center axis of an ancient bay that at one time indented the coast-line at this point. The old shore-line and, in fact, successive shore-lines can be traced from near the present coast-line in, the northwest district of British-Guiana, south-east and inland, crossing the Essequibo River near Dahli, the Demerara near Christianburg, the Berbice at the mouth of the Kuruduni River and the Courantyne at Vaka-Kuyaha Falls. The line then swings around to the northeast and again approaches the coast near St. Lau-rent in French Guiana. This article will be confined to British Guiana and largely to the valley of the Demerara River, but for geographic names .and topographic details it might, however, apply to Dutch Guiana as well. British Guiana, which comprises about 90,000 sq. mi. and is as large as England, Scotland, and Wales combined, may be divided into three belts, the alluvial belt or coastal plain, the foot-hill area (often spoken of as the sand clay belt), and the hinterland.

Jan 1, 1928

By O. C. Ralston, William C. Hunter

DUring experimental study on the separation of a zinc concentrate from the heavy sulfide ores of Jerome, Ariz., a great deal of attention has been given to proper activation of the sphalerite content of the ore. The sphalerite at Jerome contains enough iron to class it as a marmatite, as picked specimens have only about 60 per cent. zinc, whereas pure zinc sulfide contains 67 per cent. zinc. This marmatite in large pieces is black in color, but in dry powdered state is brown. A flotation froth made from it has a silvery black luster in comparison with a brassy luster caused by chalcopyrite which occurs in the same ores. The sample used in most of the experiments described below consisted of about 3000 Ib. of diamond-drill core from the zinc-bearing orebodies of the United Verde mine, and had the following analysis: Per Cent. Per Cent. Oz. peR Ton Cu............... 0.695 Al2O3............ 0.83 Ag................. 1.30 Zn............... 6.17 S................ 43.35 Au................ 0.02 Fe...............36.23 CaO............. 0.46 SiO2............. 9.27 Mineralogically, this analysis is calculated to the following, which is in agreement with the microscopic examination: Per Cent. Per Cent. Chalcopyrite................... 2.0 Schist........................... 3.2 Marmatite..................... 10.32 Quartz........................... 8.2 Pyrite........................ 73.0 Calcite.......................... 0.9 All samples were ground in a laboratory ball mill in order to leave about 3 per cent. on a 200-mesh sieve, fine grinding being essential to liberate the minerals in the ore. Most of the Jerome ores are so intimately crystallized that reasonably complete unlocking by grinding does not take place until 800 mesh is approached. Therefore, the 200-mesh grind adopted contains a considerable amount of locked mineral grains, but not so much as to render impossible the preparation of commercial grades of concentrate.

Jan 1, 1930

By P. P. Gregory

Natural petroleum gas occurring in the oil-bearing reservoirs is found to exist either as free gas associated with the oil and/or in solution in the oil. In some virgin fields practically no free gas is encountered under the reservoir conditions of pressure and temperature, although in other fields a considerable section of the "pay" horizon is occupied by free gas. In other words, a given oil field may or may not have a gas cap before the exploitation takes place. However, when the reservoir pressure is reduced to a point below the critical saturation pressure by withdrawals of fluids from the producing formation, the gas dissolved in the oil inevitably begins to come out of solution and becomes free gas. Under the controlled methods of production and drilling, a portion of this gas is produced with the oil to the surface and a portion of it remains within the reservoir to accumulate at higher structural levels toward which it migrates by virtue of its low specific gravity. The rate of growth of a gas cap in a given structure depends primarily upon the rate of decline in the reservoir pressure. If the rate of pressure decline is rapid, the gas cap likewise will grow rapidly. On the other hand, shrinkage in the gas-cap area was noted in some fields in which reservoir pressures wereincreasing. Determination of Gas-oil Contact and Thickness of Gas Cap The gas-oil contact can be conveniently located in the process of drilling a well and by electrical logging. However, very little can be found in the petroleum literature concerning methods of predetermining gas-oil contacts in producing reservoirs. Therefore, the writer feels justified in describing briefly a simple, workable, and inexpensive method of determining gas-oil contacts and outlining the limits of gas-cap areas in a field where such knowledge may be essential for efficient production and development operations. The method involves the determination of the following data: (I) Structural data, such as the depth or elevation of the top' of "pay" horizon; (2) reservoir pressures; (3) tubing and casing pressures at the well head; (4) static oil-pressure gradient; (5) static gas-pressure gradient. These data can be secured with a minimum of expense, inasmuch as the

Jan 1, 1938

By H. K. Work, H. B. Emerick

IN the past year the steel industry underwent an abrupt conversion from a war tempo to a highly competitive peacetime schedule. It is still too early to gain a comprehensive picture as to which of the measures in production metallurgy, that made the war effort so successful, will remain in the postwar production of steel, but many of them undoubtedly will fill an important place after the war. Considerable speculation has developed regarding the disposition of the war-born production facilities of the steel industry. These include new open-hearth and electric furnaces, as well as vast numbers of auxiliary, supplementary, and balancing units that increased and speeded up production beyond the normal capacities of existing melting furnaces and finishing mills. Although these facilities were installed primarily to help meet war requirements, consideration was also given, in planning, to their possible peacetime use. The new equipment is generally modern and efficient, and it seems reasonable to suppose that strategically located units will gradually be absorbed by various steel companies to supplement their own facilities, or to replace in kind, obsolete and inefficient equipment now ready to be scrapped. Some, however,

Jan 1, 1946

By H. D. Kessler, R. J. Van Thyne

Phase diagrams of the titanium-rich portion of the ternary systems from 0 to 10 wt pct Al and 0 to 1 wt pct 0, N, and C were determined. Micrographic analysis of annealed high purity arc melted alloys was the principal method of investigation and was supplemented by X-ray diffraction. TITANIUM-ALUMINUM alloys exhibit excellent properties, particularly for elevated temperature use. For this reason, the Materials Laboratory, Wright Air Development Center, sponsored an investigation of the effect of the interstitially soluble contaminants, oxygen! nitrogen, and carbon, on the Ti-A1 system. Using high purity arc melted alloys and micrographic analysis of annealed samples as the chief method of investigation, titanium-rich partial phase diagrams were determined for the ternary systems. Experimental Procedure Materials: The titanium used in the preparation of the alloys was iodide crystal bar (99.9+ pct pure) produced by the New Jersey Zinc Co. and Foote Mineral Co. The aluminum was obtained from the Aluminum Co. of America in the form of sheet. The given analysis was: Si, 0.0006 pct; Fe, 0.0005; Cu, 0.0022; Mg, 0.0003; Ca, <0.0006; Na, <0.0005; and Al, 99.99. High purity titanium dioxide purchased from the National Lead Co. was used in the preparation of the oxygen-bearing alloys. The spectrographic analysis of this material was as follows: SiO,, 0.07 pct; Fe,O,,, 0.002; A1,0,, <0.001; Sb,O,, <0.002; SnO,,, <0.001; Mg, <::0.001; Cb, <0.01; Cu, 0.0004; Pb, 0.002; Mn, <0.00005; W, <0.01; V, <0.002; Cr, <0.002; Ni, <0.001; and Mo, <0.002. Special spectroscopic graphite rod purchased from the National Carbon Co. was used in the preparation of the Ti-A1-C alloys. Alloy Preparation: Alloy ingots weighing 10 grams were melted in a nonconsumable tungsten electrode arc melting furnace using water-cooled copper hearths and a helium atmosphere. The arc was struck on a tungsten stud in the copper block to minimize contamination from the electrode. Details of the techniques have been reported.&apos;, &apos; Each ingot was inverted and remelted a minimum of four times to insure homogeneity, without opening the furnace. Remelting small control ingots of iodide titanium under similar conditions resulted in no measurable hardness increase, indicating contamination-free melting conditions were used. The alloy charges and resultant ingots were weighed to the nearest milligram. Only small weight losses were obtained upon melting, indicating that the actual compositions were very close to the nominal compositions. Check analyses substantiated this. Oxygen and nitrogen were added during ingot preparation as master alloys. An oxygen master alloy containing 25 wt pct 0 was prepared by melting iodide titanium and pressed titanium dioxide (40 pct 0) powder. The Ti-25 pct 0 alloy is more easily handled during weighing and charging than the pressed TiO, powder. Chemical analysis indicated that titanium-nitride received from an outside source contained large amounts of impurities (2.7 pct Ca). Therefore, a master alloy containing approximately 12 pct N was prepared by melting nitrided sponge titanium. As the sponge melted with difficulty, the alloy was diluted by addition of titanium to lower the melting point. The chemical analysis of the final alloy was 6.69 pct N. Both master alloys are friable and were used as —8 +16 mesh lumps resulting from crushing the ingots. NIelting the Ti-A1-0 and Ti-A1-N compositions five times produced homogeneous ingots. The preparation of homogeneous carbon-bearing alloys caused considerable difficulty. Alloys containing less than 1 pct C were prepared using spectrographic graphite rod, 1/8 in. diameter by 1/8 in. long. However, the graphite did not dissolve even with long melting times and many remelts. The ?/s in. pieces of graphite were used rather than powder because the low density powder is troublesome in arc melting.

Jan 1, 1955

By R. W. Nelson

The theoretical basis is presented for energy dissipation methods of measuring permeability in saturated heterogeneous media. Analysis starts with the equation for single-phase flow in heterogeneous porous media which is a first-order partial differential equation in the unknown permeability. This equation is reduced to a system of characteristic equations useful in deriving a differential expression for the permeability as a function of the known potential distribution. For steady flow systems the expression is integrable, giving the permeability integral for direct calculation of the distribution along successive streamlines. The boundary condition in permeability is presented and includes a discussion of the special requirement to assure uniqueness. Theoretical results and necessary computations are incorporated into two general computer programs capable of determining the permeability distribution in two- and three-dimensional steady flow systems. Results are then presented for an energy dissipation analysis using the methods and soltware to determine a field permeability thickness distribution. INTRODUCTION Theoretical work leading to the description of fluid flow in heterogeneous porous media has developed slowly and somewhat sporadically, although the areas of engineering applications predominantly involve flow in nonhomogeneous media. The lack of accurate and economical methods for measuring field permeability distributions has been a major limitation to realistic description of natural flow systems. The economical measurement of permeability using energy dissipation methods may overcome this limitation. Among other things, any permeability measurement method involves consideration of energy dissipation; as used here, "energy dissipation method" denotes the following general approach. The areal energy distribution is measured on an existing flow system in porous media. Then through appropriate analysis of the dissipation of energy in the flow system, the permeability distribution is determined throughout the region using the minimum boundary conditions required to assure a mathematically unique result. This paper presents the theoretical basis for such a method, as well as the techniques and computer software needed to carry out the analysis. The method and techniques are then used in a preliminary field application. EQUATIONS DESCRIBING FLOW IN HETEROGENEOUS MEDLA Heterogeneous as used here implies differing in kind, having unlike quantities or possessing different characteristics. Accordingly, a heterogeneous porous medium has unlike quantities or differing characteristics at different locations. More precisely, if a porous medium is heterogeneous with respect to some property, then that property is functionally dependent on the spatial location. (Media properties are considered here as macroscopic.) Specifically considering permeability k,** then k = G(x, y, z) ,............(1) or the permeability is a scalar function G of the location (x, y, z). Spatial variation of several other properties, of which porosity, dispersivity and medium compressibility are but a few, is implied by the broad title of heterogeneous porous media. The term will be used hereafter to imply only heterogeneity with respect to permeability. The porous medium is considered isotropic as implied by G being only a scalar function. Anisotropy

Jan 1, 1969

By C. R. Hocott

THE viscosity of the oil in the reservoir is one of the properties that influence its movement through the sand to producing wells. Measurements of viscosity, therefore, are pertinent to problems associated with well behavior and with the estimation of recoveries, and afford an indirect means for partial evaluation of various methods of controlling reservoir behavior. The effect of dissolved gases on the viscosity of crude oil has been determined,1,2 but no data have been published on the viscosity of repre-sentative samples of reservoir oils. This paper describes a simple instrument that has been used to determine the viscosities of a number of subsurface oil samples at the temperatures and pressures existing in the reservoirs, and presents the results of the determinations for typical fields.

Jan 1, 1940

By P. D. Zemany, G. W. Sear, B. W. Roberts

Vanadium metal is embrittled by hydrogen at a temperature as low as 250°C when held in the presence of manganese metal and water vapor in a rough vacuum. It is established that the property changes are caused by the catalytic decomposition of water vapor at the vanadium surface and the diffusion into and solution in the vanadium of the resultant hydrogen. It is found that manganese is a necessary component of the catalyst. The manganese is transported in the vapor phase by an unknown molecule. A deuterium tracer experiment demonstates the role of water vapor in the embrittle-ment process. VANADIUM metal foils were observed to become embrittled&apos; at a temperature of about 300 °C when held in the presence of manganese metal and a small amount of moist air, This paper describes the investigation to find the embrittling agent and an understanding of the relatively low temperature reactions that are involved. Experimental The vanadium metal foil used was prepared by cold-rolling and pack-rolling 32 mil sheet" in a series of steps down to 1 mil foil. The original observation was confirmed by sealing vanadium foils of 3 x 10 sq cm into individual Pyrex tubes with manganese powder† and a con- trol tube containing only the vanadium foil. These tubes were evacuated to 10 -5 mm Hg without baking and sealed. After heat treatment for 200 hr at 300°C, the control foil showed no change in duetility, whereas the foil contained in the manganese— containing tube was embrittled. The visual appearance of each was unchanged. A series of Pyrex sample tubes, about 2.5 cm diam and 25 cm long, were prepared, each containing a 3 x 10 sq cm piece of foil and 5 g manganese powder at the lower end of the tube. By reducing the time of anneal and the temperature of these samples, it was found that embrittlement could be created at 250°C in a time as short as 1 hr. Since the vanadium metal used here has been drastically cold-worked by rolling, it is assumed that it contains a maximum number of dislocations. To check the possible necessity of dislocations in this low temperature reaction, a vanadium foil sample was annealed in Vycor for 2 hr at 800°C to re crystallize and reduce the dislocation concentration. Metallographic examination showed grains which were not visible before annealing. The embrittlement procedure was carried out at 300°C and 3 hr. Upon checking the foil no embrittlement was observed. Further experiments demonstrated that about 6 hr at 300°C are required to create embrittlement in the foil. This delay in the onset of embrittlement in the vanadium foil suggests but does not prove that dislocation channels play a role in the embrittlement phenomena. If manganese metal is necessary for this low temperature embrittlement, do other elements in the transition metals group yield the same result? To check this qualitatively, a group of elements of similar atomic radii were obtained and sealed as before into Pyrex tubes with a sheet of vanadium foil. These tubes were annealed at 250°C for 6 hr and included (with radii)-2 A1 (1.4A), As (1.25A), Be (1.2A), Co (1.25A), Cr (1.45A), Cu (1.25A), Fe (1.25A), Ga (1.2A), Ge (1.25L%), Mn (1.3A), Ni (1.25A), Si (1.2A), Ti (1.45A), Zn (1.3A), air, H,O, 10 cm Hg of dry hydrogen, and MnO, powder. Upon testing the above sample foils for brittleness, only the manganese-containing tube yielded a brittle foil. Manganese Transport—To eliminate contact of manganese metal powder and vanadium foil, sample tubes were prepared with fritted glass barriers. The embrittlement reaction was still found to occur. Thus, the mode of transfer of manganese is certainly vapor transport. A vanadium foil was embrittled by this mechanism in an evacuated Pyrex tube for 8 hr at 300°C. By means of X-ray fluorescence analysis,&apos; the amount of manganese added to the surface was established at 5 ±2 x 10 -6 g per sq cm. Since the average rate of manganese deposition is known, an effective average pressure of an assumed carrier compound can be computed. ___ P = M/T v2p mkT

Jan 1, 1959

By F. B. Plummer

THE physical properties of oil-producing sands, such as grain size, porosity, and permeability, are becoming more and more important in petroleum production engineering as oil fields are being repressured and rejuvenated. A number of excellent papers have been published recently on all three of these properties. Faucher, Lewis and Barnes1 give a com-plete survey of the work done through 1932 and contribute also much information on sands that they themselves have examined. Muskat and Botset,2 Wykoff, Botset, Muskat and Reed,3 Hurst,4 and Muskat5 have contributed a great deal to the theory and actual measurement of flow of liquids and gases through porous media. Muskat and Botset have measured the permeabilities of different sands with gases and liquids. They find that the radial is always slightly under the linear permeability. However, in most of the previous experiments small samples of the sand were used, and the method of production of fluid or gas through the sands has not been very close to actual oil-field conditions. In addition, so far as the authors are aware, no measurements of linear and radial permeabilities have been made simultaneously under exactly the same conditions. The multiple permeability apparatus described here is a part of the equipment being acquired by this laboratory for thorough investigation of the physical properties of producing sands. It possesses certain advantages for comparative studies of liquid flow. Additional data and descriptions of other instruments will follow in papers to be written later on. The essential features of the permeability apparatus are as follows:

Jan 1, 1934

By Walter L. Crow

MUCH has been published on highly technical phases of grinding. Very little has been written on how a mill man can improve his operations by determining the optimum size assortment of grinding balls that should be added as a makeup charge. This ball rationing is not to be confused with the ball ration used as an initial charge when the mill is started up. Ball rationing is considered for one or more of the following purposes: 1) to increase throughput of the mill, 2) to reduce the power required per ton of ore ground to the desired size, 3) to reduce steel consumption per ton of ore ground, 4) to improve product size, and 5) to lower retention time of ore in the mill.

Jan 7, 1957

By John G. Baragwanath

THE September issue of the Engineering and Mining Journal carried an item regarding the Cercapuquio Mining Co. which was mentioned as a large producer of lead, zinc, and cadmium, situated near Huancayo, Peru. The paragraph caught my eye because I had not heard of the property in thirty years and I recollect all too well the circumstances of its accouchement. In 1916 1 was making my headquarters in the town of Huancayo, then the terminus of the Central Railway of Peru, and was examining mines and prospects in that general area for Cerro de Pasco. In the course of my work I became acquainted with an engaging and energetic "practical" miner named Balarin, a Dalmatian living in Huan¬cayo, and made numerous trips in his excellent company. One day Balarin came to the down-at-heels hostelry where I stopped and told me that a Cholo prospector, a character by the name of Jose, had just reached town and claimed to have made a discovery in a little known locality called Cercapuquio. Lead-silver, Balarin said, and showed me a sample of galena about the size of his fist. "Fine," I remarked. "When do we leave?"

Jan 1, 1947

By R. S. Dean

REQUIREMENTS for war materials have led to large scale experimentation upon metallurgical innovations. It is of interest to inquire what this may contribute of permanent value to our existing technology, as innovations adopted during war are apt to be discarded promptly at its end. This is because utilization of substandard ores usually requires a new technology for ore treatment, and a new use-pattern for employment of the products. Thus two very different problems are involved: first, devising a process; then, adopting its products by industry, with readjustments of the use-pattern if necessary. A new process may be as good or better than an old one, but the readjustments required for use of its products may prevent its general adoption if this implies scrapping existing plants and investing much additional capital. Metallurgical innovations are of three kinds: I. The use of substandard material in processes already established; 2. The grading-up of substandard material to render it more suitable for established processes; 3. The adjustment of technology and use-pattern to the raw materials that we have.

Jan 1, 1945

By R. G. Hite, R. G. Rowe

The Crandon deposit, located in northern Wisconsin, is a 65.8 million ton Precambrian volcanogenic massive sulfide deposit which averages 1.4% copper and 5.8% zinc. The deposit is classic in origin, mineralogy and shape. Comprehensive understanding of the geology of both the deposit and the project site has been fundamental to the credibility and success of project feasibility studies and regulatory permit preparation. Mine development in the current investment and regulatory climate requires thorough and timely application of geologic tools. From 1977-1980 geologic activities were focused on the typical objectives of orebody delineation, reserve estimation, depositional geology, and general site investigation. Results from these programs formed the basis for the project&apos;s preliminary feasibility studies. Since 1981 further geologic investigations have provided criteria for project design, site management, and operational permitting. Activities have included mine entry position definition drilling, developing geostatistical reserve modeling, large diameter (150 mm) core drilling for mill pilot samples, rock mechanics testing, and evaluation of the glacial overburden/deposit geohydrology for computer simulation.

Jan 1, 1984

By R. E. Reed-Hill

The shear continuity conditions under which one mechanical twin may cross another are considered. Twin intersections usually involve various types of slip deformation in addition to twinning. Because the shear of the crossing twin may be partly transmitted through the crossed twin by slip mechanisms, continuity of the twinning shear vectors is not required at a twin intersection. It is concluded that analyses based on twin intersections should not he used as an independent method for deducing twinning elements in newly observed twinning modes. WHEN one mechanical twin passes through another, a twin intersection is said to occur. In the simplest form of intersection, Fig. 1, the crossing of one twin by another is accomplished with the aid of a second-order twin induced, in the twin that is crossed, by the crossing twin. The subject of twin intersections is significant to the field of deformation studies because it has been postulated by cahn1 that twin intersections should occur only under the following continuity conditions: 1) the traces of the primary and second-order twin must be parallel to each other in the plane of the crossed twin; 2) the direction 771 and magnitude, S, of the twinning shear must be identical in the crossing and second-order twins; also, the sense of shear must be the same. If these postulates are valid they constitute a valuable tool for determining twinning elements of newly observed twinning modes in metals. In his classic paper in 1953 on the plastic deformation of a uranium, Cahn1 used these continuity conditions to deduce twinning elements for several uranium modes. However, in the same year, pratt2 showed that both of Cahn&apos;s continuity equations were violated for (1012) twin intersections in zinc. Later, Kiho and Maruyama3, 4 showed that Cahn&apos;s second postulate was violated in {301) and (101) twinning in tin and (101) twinning in bismuth. In spite of this documentation that Cahn&apos;s second postulate is often violated, several recent papers5&apos;6 have been published which have attempted to use the condition of continuity of twinning shear vectors for the evaluation of twinning elements. The primary purpose of this paper is to call attention to the possible ambiguity inherent in applications of Cahn&apos;s postulate, and to present additional information concerning the nature of twin intersections.

Jan 1, 1964

By BLAllEY STEVENS

(Canal Zone Meeting, November, 1910.) I. INTRODUCTION. TEH object of this paper is to show how igneous intrusion is governed by definite mechanical laws. A distinction is made between dikes and fissures, and the various characteristics of intrusions are explained on an exact scientific basis. The modification of rock-stresses by intrusion is then considered and extensive isostress regions are recognized. Finally, a complete classification of intrusions is constructed covering all pos-sible cases. The generalizations of observed data, taken from Geikie&apos;s Textbook of Geology, conform to the laws of intrusion herein stated, and the deductions based upon these laws. No authority, however, is quoted for the type which I have named a corrugated intrusion. Its existence is a necessary deduction from the laws of intrusion, and even the entire absence of examples in technical publications cannot disprove its reality. In all probability, corrugated fissures would have remained undiscovered, but for the working of mineral veins. As intrusions of tabular form are seldom worked for commercial purposes, it has been left for theory to anticipate the discovery of corrugated dikes. In the light of these laws of intrusion and the corresponding laws of fissures,1 there seems to be a remarkable uniformity of stress-distribution in rocks at moderate depths. This renders .possible the mathematical calculation which should help us to approximate exact science in this and kindred branches of applied geology.

Jan 1, 1911

By W. D. Potter, E. T. Peters

Single-crystal films of boron have been prepared by thermal reduction of purified BCl3 with subsequent deposition of boron onto oriented silicon substrates. The structural properties of films prepared under various experimental conditions have been determined by light microscopy and "grazing-" angle electron-diffraction analysis. An orientation relationship is proposed for silicon and a-rhombo-heclral boron which can be described as: (111)Si (112)B; [110]Si [110]B ElEMENTAL boron is known to have a high energy gap* and consequently has potential value as a high- *Energy gaps of 1.35 to 1.55 ev1-3 and 2.0 ev4 are reported for ß-rhombohedra1 and a-rhombohedra1 boron, respectively. temperature semiconductor.5 Exploitation of this property, however, has been hampered by the unavailability of pure, single-crystal boron. Two recent symposia6,7 have treated the subjects of purification, crystallization, crystal structure, and properties of boron and provide a foundation for further investigation in these areas. The structure, lattice constants, and observed ranges of stability for four reported polymorphs of boron8°12 are listed in Table I. The rhombohedral structures are generally accepted as true polymorphs whereas the tetragonal structures are believed to be transient. Most currently available single crystals of boron are grown by Czochralski and floating-zone methods. Unfortunately, these crystals generally contain numerous defects and are highly strained as a result of the polymorphic transformations and thermal contractions which accompany cooling. Recently, Armington, Potter, and Tanner13 have reported the formation of single-crystal films of boron on silicon single-crystal substrates through thermal reduction of BC13 by hydrogen. Boron E. T. PETERS, Junior Member AIME, is Senior Scientist, ManLabs, Inc., Cambridge, Mass., and W. D. POTTER is Research Chemist, Air Force Cambridge Research Loboratories, L. G. Hanscom Field, Bedford, Mass. formed at temperatures near 1000°C was identified as the a-rhombohedra1 form, consistent with expectation. The present paper describes a continuation of this work with specific reference to characterization of the structural features of the deposited boron films. The ultimate goal of this program is to produce large-area single-crystal films of a-rhombohedra1 boron to be used for electrical and optical studies by other workers. PREPARATION OF BORON FILMS The experimental procedure of preparing thin films is similar to that described by Theuerer14 for the epitaxial growth of silicon by thermal reduction of SiC14 and has already been described as applied to the preparation of boron thin films.13 Briefly, a mixture of BCl3 vapor and dry hydrogen is passed over a heated silicon substrate. Thermal reduction of the BC13 allows deposition of boron on the substrate. The substrates were {111}-oriented, single-crystal silicon. Square specimens 0.63 cm on an edge by 0.1 to 3.0 mm thickness were prepared by

Jan 1, 1965

By H. A. Dierks

PENNSYLVANIA&apos;s anthracite region lies in the heart of the richest and most densely populated area of the U. S. Nearly 70 million people live within a radius of 500 miles, in which 130,000 manufacturing plants employ more than 8 million workers. The region comprises some 3000 sq miles and contains 484 sq miles of coal measures, which folding and erosion have divided into four separate and distinct fields, known as the Northern, Eastern Middle, Western Middle, and Southern. One million people live in the anthracite region proper, and their prosperity depends to a great extent on the anthracite industry, which produces more than $200 million in new wealth for the U. S. each year. Nearly 80 pct of the tonnage shipped out of the region is handled by nine railroads, which depend on this traffic for a large part of their revenue. It follows that the economic health and the very existence 0: this industry is of real concern not only to the region itself but also to the state of Pennsylvania and the country as a whole. Anthracite mining is one of the oldest mineral industries in America. About 1760 burning rock or stone coal was discovered on the hillsides of northeastern Pennsylvania. Within a few years a systematic search for coal bed outcrops was under way, and hand mining was begun. At first production was very limited, since anthracite was difficult to burn and was not readily accepted as a fuel. Pennsylvania anthracite is one of the densest and hardest of all coals, and its content of volatile matter is low. Consequently it does not ignite easily and it burns without smoke. About 1808 Judge Fell of Wilkes-Barre burned anthracite in an open grate fireplace and demonstrated proper handling of an anthracite fire. From

Jan 1, 1958

Striving to do a better job of ad- ministering the letter and spirit of the Federal Coal Mine Health and Safety Act of 1969, the Interior Department recently invited criticism-and got it. The criticisms were voiced on July 1 and 2 at the first of a series of public meetings being held by the Office of Hearings and Appeals at the Department&apos;s behest. Later meetings, at which all interested parties are invited to comment, are to be announced in the press and the Federal Register. Persons wishing to participate in the meetings should contact the Director, Office of Hearings and Appeals, 1015 Wilson Blvd., Arlington, Va. 22203. At the first Hearing, USBM Director Elburt F. Osborn outlined the progress his agency has made to date in implementing the law on three fronts: enforcement, education and research. Since the Health and Safety Act became law on December 30. 1969, he said, the Bureau&apos;s force of inspectors has grown from a mere 300 to almost 1100, while mine inspections have increased from 10,265 in 1970 to 11,021 for the first six months of 1971. On the educational front. Osborn said, the Bureau now has some 60 instructors who have trained about 50,000 miners in safety procedures since March 30. 1971. Classes at the new Federal Mine Safety Academy for both government and industry personnel begin on September 1, 1971. he added. Health and safety re- search, meanwhile, has been allot- ted $20.1 million for the 1971 Fiscal Year. Of this, $8.1 million is assigned to the Bureau and $12.3 million to contracts with universities and private companies. Admittedly, Osborn said, the mine fatality rate is still unacceptable, hut it was lower in the first half of 1971 than ever before---0.73 per million man hours and 0.31 per million tons of coal.

Jan 1, 1971