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By G. H. Montgomery

THE PROPERTY of Aunor Gold Mines, Limited, consists of eleven claims, located in Deloro township, approximately three miles southeast of the town of Timmins. Production began in 1940 and currently the mine is operating at a rate of 485 tons per day. GEOLOGY AND MINE DEVELOPMENT The ore zone at Aunor occurs in altered lavas bounded on either side by soft talc-chlorite schist, locally known as 'soapstone'. The zone has a strike of N.80°E, dips 60° North, and varies in width from 0 to 250 feet. Within this zone the main orebody has a westerly plunge, away from the No. 1 shaft area (Figure 1). The mine is developed by a vertical three-compartment shaft from surface to the 3,082-foot horizon. Working levels are spaced at 125- foot intervals from the 625-foot to the 1,625-foot horizon, from which to tl1e 2,125-foot level the interval is 250 feet.

Jan 1, 1957

By G. A. Vissac

IN THE preliminary design of a coal washery, the most important factor to evaluate is the ash content of the final product. The ash content permissible may be imposed by market demands, but, in the final analysis, sooner or later - as most consumers today are buying coal on a 'heat value' basis - the coal operator has a certain margin of latitude. and the ash content of the coal to be delivered can be determined on the basis of maximum returns and highest profits. A few years ago, the most desirable separation was selected on the basis of the plus-minus 0.10; that is, the most desirable gravity of the separation was selected at the point showing a minimum amount of near gravities in the raw coal. The reason for this was an expected wide error over these near gravities. Today with the recent development of cry accurate, automatically controlled cleaning apparatus, a much larger latitude is possible, and the most desirable gravity of separation can be selected, almost exclusively, on the basis of the economic factors involved. To illustrate these new methods of investigation we shall give two examples, based on actual coals from the western United States.

Jan 1, 1957

By Howard Reiss, C. S. Fuller

A theoretical and experimental study has been made of those interactions between holes and electrons which influence the solubilities of donors and acceptors in semiconductors. The major portion of the work concerns the solubility of lithium in silicon doped to varying degrees with boron. This solubility increases with increasing boron content in a manner predicted by theory and exhibits the expected temperature dependence. A qualitative experiment in germanium is described which demonstrates, in accordance with theory, that doping with a donor decreases the solubility of another donor. SEVERAL authors have discussed the possibility that holes and electrons behave like chemical entities and influence the solubilities of ionized impurities, Wagner was the first to invoke this concept in connection with his studies on nonstoichio-metric oxides. He used it again in explaining the solubility of hydrogen in molten binary alloys. In a theoretical paper,' Reiss drew attention to the fact that solutions of impurities in semiconductors

Jan 1, 1957

BEFORE me is a colored mining-claim map of the productive portion of the Robinson Mining district-sometimes called the Ruth-Kimberly area-that lies a few miles west of Ely, Nevada. It covers an area of 20 sq mi and at the end of 1954 had produced just under 2,000,000 tons of copper and about 2,000,000 oz of gold as a by-product. The three principal colors on the map and the meaning of each are: Red -Property of the Nevada Mines Division of Kennecott Copper Corporation, formerly known as the Nevada Consolidated Copper Company. Yellow -Property of the Consolidated Coppermines Corporation. Green --Consolidated Coppermines property under lease to Nevada Mines. The striking feature of the map is the crazy-quilt intermingling of the colors and the tendency of property lines to intersect ore bodies. For example, the westerly one-fourth of Nevada Mines' Copper Flat pit, source of most of the ore,up to date, is in Coppermines property. Nearly half of Nevada Mines' Veteran pit is on leased claims; and Nevada's new Deep Ruth shaft is on a right of way on ground originally owned by Coppermines. On the other hand, the original Ruth underground mine and the new Kimbley pit are on Nevada Mines property; and the Morris and Brooks opencut mines, the most important of Cop-

Jan 1, 1957

By G. W. P. Rengstorff

In an effort to find an oxidation-resistant alloy of molybdenum, binary and ternary alloys containing aluminum, chromium, cobalt, iron, nickel, silicon, titanium, tungsten, vanadium, and zirconium were screened. Fourteen other alloying additions were also tested. Many of the alloys were more oxidation-resistant than molybdenum, but none were entirely satisfactory. MOLYBDENUM oxidizes extremely rapidly above 1450°F in air. At 1800°F, a loss of metal at the rate of 0.1 in. in 4 hr is typical. The high speed of this oxidation may be judged by comparison with the oxidation rate of 0.1 in. per year (0.00005 in. in 4 hr), sometimes taken as the maximum permissible oxidation rate at 1800°F for a satisfactory Fe-Cr-Ni alloy. Great strides have been made in the development of coatings and cladding to protect molybdenum from oxidizing atmospheres. These developments in surface protection will undoubtedly make it possible to take advantage of the excellent hot strength of molybdellum and its alloys in many new applications. Still, even the best coating can protect molybdenum only as long as the surface layer is unbroken. Research was undertaken to determine whether an alloy of molybdenum could be found which would resist oxidation. Such an alloy would not deteriorate suddenly when the protective surface layer was destroyed in a small area. In seeking an alloy of molybdenum to resist oxidation, the physical properties of molybdenum could not be sacrificed entirely. The development of an alloy with the desired resistance to oxidation was not achieved. The information obtained on the effect of a large number of elements on the oxidation of molybdenum is, however, of value in the development of coatings. Indeed, many of the alloys tested for oxidation resistance were already known to have poor mechanical properties but were tested to aid in the development of coatings. Oxidation of Molybdenum The rapid oxidation of molybdenum is usually attributed to the volatility of Moo,,. Gulbransen and Wysong have shown that molybdenum oxidizes very slowly up to 850°F, the temperature at which the oxide film begins to evaporate. Melting as well as evaporation of molybdenum oxides promotes the oxidation of molybdenum. MoO melts at 1465°F. MOO, the oxide which is believed to form at the metal-oxide interface, combines with MoO, to form a eutectic having a melting point of 1432°F.' The liquid oxide, even if nonvolatile, could cause poor resistance to oxidation by allowing easy transport of molybdenum and oxygen ions through the oxide. Actually, a sudden increase in the rate of oxidation of molybdenum at 1460°F has been observed to coincide with the appearance of a liquid phase. The formation of a volatile oxide is not unique with molybdenum. The problem is also encountered with vanadium, tungsten, and some of the Pt-Pd group of metals. Vanadium not only forms the volatile V2O3 but, like molybdenum, forms a liquid oxide coating. Few attempts have been made, however, to prevent the rapid oxidation of these metals by alloying. Oxidation of Molybdenum Alloys At the beginning of this work, very little was known of the oxidation resistance of molybdenum alloys. It was known that molybdenum disilicide (with 37 pct Si) has extremely good oxidation resistance,' but this compound is so brittle that it has few uses. It is an effective protective coating for molybdenum when allowance can be made for its brittleness. Chromium was known to retard the oxidation of molybdenum,' but at least 50 pct Cr was necessary to have an appreciable effect. Other, unpublished, reports show that a few other alloys have been given preliminary tests, but the results have not been promising." Choice of Alloys to be Investigated An alloying element might be expected to protect molybdenum in either of two ways: Its oxide might combine with molybdenum oxide to form a stable, nonvolatile complex oxide (a molybdate); or the oxide of the alloying element might form in preference to molybdenum oxide, developing an impervious layer which would prevent the formation of a volatile molybdenum oxide. The knowledge available about the formation of molybdates was meager. Therefore, the initial study was made on alloys of molybdenum with elements having especially stable oxides. On this basis, binary and ternary alloys containing the following six elements were investigated: aluminum, chromium, titanium, zirconium, silicon, and vanadium. Nickel was also added as an alloying element. Although it does not form a more stable oxide than molybdenum, it does impart some oxidation resistance to copper and iron. Its inclusion in the study was fortunate because its alloys proved to be the most promising of those first tested. Apparently nickel formed a stable molybdate. Because nickel was effective in reducing the oxidation rate of molybdenum, the elements iron, cobalt, and tungsten were added to the list. The ten alloying elements mentioned form ten binary and 45 ternary alloying systems with molybdenum. A series of alloys was tested in each of these systems. In addition, at least one test was made on the effect of each of the following alloying elements:

Jan 1, 1957

By O. C. Blade

Sales of diesel fuel in the United States during the post year and a half have increased greatly. In 1955 over 174 million barrels were sold of which 80 million (or 46 percent), were used by the railroads, and over 44 million barrels (25 ½ percent) of the fuel were used in trucks, busses, tractors, and heavy moving equipment. Vessels (12 percent), industry (9 ½ ), the military forces (4 ½ ), power plants (2), and oil companies (1/2 percent) account for the remainder. 2/ Dally deliveries of diesel type fuel from refineries averaged over 16,750 barrels during the first six months of 1956 in comparison with 15, 250 barrels during the corresponding period of 1955. 3/ Information on the properties of diesel fuel is very important to the petroleum industry, engine manufacturers, and consumers. To supply such information the American Petroleum Institute and the Bureau of Mines, United States Department of the Interior, under cooperative agreement, are conducting annual surveys of diesel fuel oil produced in refineries in this country.

Jan 1, 1957

By J. W. McCammon

CRANGES in construction ideas and the continually rising costs of labour and conventional building materials, particularly since World War II, have prompted widespread investigations into the development and adaptation of new materials to meet the new requirements and to help reduce costs. Lightweight aggregates have been prominent in these investigations. The lightweight aggregates most commonly used today are foamed slag, cinders, pumice, diatomite, exfoliated vermiculite, expanded perlite, and bloated clay or shah. Lightweight aggregates contribute to the building industry in several ways: ( 1) in large structures the reduction in deadweight effected by the use of lightweight materials reduces the amount of reinforcing and structural steel necessary to support the structure; ( 2) the decrease in weight of lightweight blocks makes handling easier and faster; (3) pre-fabricated floor and roof slabs and tilt-up walls of lightweight concrete have become feasible and popular; ( 4) lightweight aggregate concrete has good nailability and is easily channelled; (5) concrete and plaster made with lightweight aggregate have good heat and sound insulation properties.

Jan 1, 1957

By Richard N. Appling

This compilation presents information obtained through investigation of manganese deposits and a reconnaissance of potential manganese-bearing areas of southwestern Oregon and Del Norte County, Calif., from October 1952 to September 1955. The report includes maps, assays, and preliminary examination data on 39 manganese deposits distributed throughout Curry, Coos, Douglas, Josephine, and Jackson Counties, Oreg., and 1 deposit in Del Norte County, Calif. On the basis of mineral content the deposits can be divided into three groups: 1 Manganese silicate deposits, manganese oxide deposits, and manganiferous iron de-posits. Generally the oxides occur along the coast in the Curry-Coos County area, the manganiferous iron deposits are in the Josephine-Douglas area, and the manganese silicates are found in both the Josephine-Douglas and Jackson County areas. The deposits are characteristically irregular in form and usually small. Most silicate and manganiferous iron deposits are in metasediments of Triassic (?) age; oxide deposits are in sediments varying in age from Jurassic to Eocene.

Jan 1, 1957

By S. K. Nowak

The lithium solubility limit in solid aluminum was determined by the use of micro-graphic techniques. The solubility limit thus established was shown to be a true equilibrium by checking the reversibility of AlLi phase precipitation and dissolution around the equilibrium temperature. The experimental results fit a straight line by plotting log N(LI) against 1/T. The metallurgical reasons explaining the lack of agreement among previous investigations are discussed. THE solubility limit of lithium in solid aluminum was determined by Shamray and Saldau1 by micrography and by Grube et al.' and also Voss-Kiihler- by measurement of electrical resistivity. Since the addition of lithium induces extremely small changes in the aluminum lattice, X-ray techniques could not be employed for this purpose; in fact, the addition of lithium does not cause an expansion of the lattice as might be expected from a consideration of atomic radii, but causes a small contraction from 4.040 to 4.037A3, 4 when the solvent aluminum is saturated with this element. An analysis of the results from previous investiga-tions'" shows that with improvement of investigation techniques the solubility limit tends toward a lower lithium content. Again, some of the author's own experimental results on the action of atomic hydrogen on A1-Li alloys seemed to indicate that the solubility of lithium should be much lower, i.e., about 0.3 pet at 300°C: instead of 1.15 pet, the lowest published value.4 For the foregoing reasons it was decided to investigate this problem. The aluminum and the lithium used for this purpose were of the highest purity. The lithium solubility limit was determined by metallographic techniques, in particular by the use of a reagent especially developed for the purpose of revealing the AlLi phase. The solubility limit thus determined was shown to be a true equilibrium by checking the reversibility of AlLi phase dissolution and precipitation around the equilibrium temperature. All of the experimental work was carried out in 1951 at the Centre d'Etudes de Chimie Metallur-gique at Vitry, France, under the direction of Georges Chaudron.

Jan 1, 1957

By Harold R. Bradford

EXPANSION initiated during and after the war has placed industrial plants in new areas and increased reduction and manufacturing facilities in communities already established. With added expansion interest has grown in possible area contamination from waste products. Evolved flue waste contains many chemical contaminants that may or may not cause concern; however, atmospheric pollution has always been a problem to industrial communities. For some time effects attributed to small quantities of compounds of fluorine in various waste gases have been studied by industrial, medical, agricultural, and associated interests.1,2 Aside from an article by Churchill, Rowley, and Martin in 1948,3 little has been published on the subject of fluorine in coal except by foreign investigators.

Jan 1, 1957

By J. D. Milburn, H. J. Hill

In quantitative interpretation of electrical logs the presence of clay minerals introduces an additional variable which further complicates an already complex problern. Although recognizing the difficulties introduced as a result of the heterogeneity of natural sediments and despite the present incomplete state of knowledge regarding electrochemical behavior of shales, dissemirzated clay minerals and concentrated electrolytes, it was felt that useful empirical correlations might be obtained from experimental investigation. Six typical sandstone formations, having a wide variety of petrophysical properties, were selected for the study. Approximately 45 samples from each formation were selected to satisfactorily represent the range of pore size distribution within the particular formation, As a matter of general interest, four limestone formations were also included in the investigation. Previously proposed equations relating to resistivity, SP and interrelationship of the two phenomena have, where possible, been tested with data obtained in this investigation. These equations do not satisfactorily describe experimental behavior of samples through all degrees of shaliness or throughout the range of brine solution resistivities normally encountered in logging practice. An empirical equation has been developed which quantitatively relates formation resistivity factor to satirrnting solution resistivity, porosity, and "effective clay content." This relation is indicated to be uniformly applicable to clean or shaly reservoir rocks. It is shown that both the SP and resistivity phenomena of shaly samples are related to the sample cation exchange capacity per unit pore volume. The independent chemical determination of this parameter is thus a means of determining the "effective clay content" of samples. Some implications regarding theory and electric log interpretation of shaly sands are discussed. INTRODUCTION The use of electrical resistivity logs as a means for estimating formation porosity is based upon the original work of Archie1. It was shown by empirical methods that the resistivity of a rock, when 100 per cent saturated with brine solution, could be related to rock porosity through the equation, F = Ro/ RW = f-m.......(1) where F, the formation resistivity factor, is defined as the ratio of the resistivity of the 100 per cent water saturated rock, Ro, to the saturating solution resistivity, Rw; f is the ratio of pore volume to bulk volume; and m is the slope of the average line when the data are plotted on log-log paper. This relation was established for relatively shale-free formations containing water having high salt concentrations, and under these conditions F may be considered constant for a given rock sample. Applications of Eq. 1 to interpretation of logs of shale-free formations has been quite successful when satisfactory formation water resistivity data could be obtained. The most readily available means of estimating formation water resistivity is the self-potential log. Conventional methods of SP log interpretation involve correct.

Jan 1, 1957

With the sinking of the new No. 3 Shaft and the increasing depth and northward movement of the mining operations, improved ventilation of the mine workings became necessary and it was decided to sink a new upcast ventilation shaft midway between No. 2 Shaft and No. 3 Shaft.The shaft is finished to 16 ft. internal diameter and connects with the mine workings at the 2,600-ft. level. It is lined with unreinforced Concrete approximately 12 in. thick. The shaft sinking routine was drilling, blasting and mucking by hand using a 27-cub. ft. capacity bucket. The concrete lining was poured in conjunction with the sinking and was normally finished within 30 to 50 ft. of the shaft bottom.

Jan 1, 1957

By N. A. Eilertsen

Among the numerous Low-grade manganese deposits in eastern Aroostook County, Maine, the Dudley deposit near Mapleton in the northern district is one of the few known to contain an appreciable tonnage averaging above 10 percent manganese. The ore body, consisting of stratified manganiferous hematitic shale, is over 5,000 feet long and ranges in width from 30 to 175 feet. The deposit was extensively explored during 1942-44 by the Manganese Ore Co., a subsidiary of M. A. Hanna Co. of Cleveland, Ohio. Data obtained from this work were made available to the State and Federal Geological Surveys for estimating ore reserves. An estimate by the Maine Geological Survey, using a 10-percent manganese cutoff and to a depth of 200 feet, shows 609,000 long tons of manganese metal in material averaging 12.6 percent manganese. By lowering the cutoff limit to 5 percent manganese, the estimate was increased to 919,000 long tons of metallic manga¬nese in material averaging, 10.4 percent manganese,

Jan 1, 1957

By Wallace E. Anable

This investigation by the Bureau of Mines was conducted chiefly on Cuban serpentine nickeliferous ores to determine whether these materials would be amenable to direct carbothermic reduction in an electric furnace to produce a low-carbon ferro-nickel. The project was carried out as one of several under a Memorandum of Agreement between the Bureau of Mines and the General Services Administration (Contract GS-OO-B (D)-152l). Two ore samples were received for this investigation. One was a mixture of nickeliferous serpentine from the North Ocujal, South Ocujal, and San Juan claims of the Nicaro Nickel Co. The other sample was a mixture of material from the Ramona and the Lorna Mulo claims of the Cuban Nickel Co. Most of the ore from the Ocujal-San Juan deposits and about 40 percent of the sample from the Ramona-Lorna Mulo deposits were calcined before smelting. The remainder of the sample from the Ramona-Loma Mulo deposits was smelted after drying to about 8 percent moisture. An arc-resistance, selective-reduction smelting technique was employed in these tests. Either bagasse alone or a mixture of bagasse and coke was used for reductants. No flux was used in the furnace charges.

Jan 1, 1957

President-Mrs John R C Mann, 90 Edgemont Road, Scarsdale, N Y First Vice-President-Mrs C P Pollock, 27 Dante Street, Larchmont, N Y. Second Vice-President-Mrs Mendum B Littlefield, 40 Lincoln Street, Larchmont, N Y Third Vice-President-Mrs J B Cunningham, 236 East 2nd St , Tucson, Ariz Fourth Vice-President-Mrs Theodore Loftus, 410 Cowles St, Fairbanks, Alaska Fifth Vice-President-Mrs George L Craig, 109 Calumet Avenue, Calu¬met, Mich Recording Secretary-Mrs Arnold H Miller, 601 West 115th St, New York 25, N Y Assistant Recording Secretary-Mrs R J Mechin, 66 East 79th St, New York 21, N Y Corresponding Secretary-Mrs John A Poulin, 4 East 70th St , New York 21, N Y Treasurer-Mrs Robert W Rowen, 29 West 39th Street, Room 914, New York 18, N Y Assistant Treasurer-Mrs Samuel H Dolbear, 1000 Park Avenue, New York 28, N Y Assistant Treasurer-Mrs Roger H Sherman, 8 Roman Avenue, Forest Hills Gardens 75, N Y.

Jan 1, 1957

By Bruce I. Thomas

As a part of the United States Department of the Interior program for developing natural resources in Alaska, the Bureau of Mines studied the tin-bearing gold-placer deposits in the Tofty area of the Hot Springs district in central Alaska. The principal objective of the Bureau's work was to obtain facts about the extent and character of the placer deposits (including tailing) to indicate the economic or strategic tin-production potential of the Tofty "tin belt." A secondary objective was to determine (if possible) the bedrock Source of the cassiterite and other minerals found in the placer deposits. The placer phase of the work was begun in July 1954 and was continued during the 1955 and 1956 field seasons. Extensions to, and connections between, known placer channels were sought by 82 churn-drill holes. The Bureau drilling did not expand the placer deposits beyond the limits established by drift-mining operations and by previous drilling done by private concerns.

Jan 1, 1957

By H. W. Mead, C. E. Birchenall

SELF-DIFFUSION of iron in austenite is a process which may play a significant role in some of the practically important reactions which occur in solid irons and steels. It also provides a system in which the interaction of vacancies on substitutional sites and atoms in interstitial positions may be investigated. For both purposes, accurate values of the diffusivities are required. Two sets of previous measurements exist, each containing features which require checking. In the course of an investigation to determine the rate of diffusion of iron in certain steels, Garwick and Rosenqvist' measured the self-diffusion coefficient of iron in a 0.10 pct* C steel and obtained a dicated that while at lower temperatures D increased with increasing carbon content, at the higher temperatures it first increased and then decreased. At the same time the activation energy decreased linearly from a value of 69,000 cal per g-atom for pure iron to 33,000 cal per g-atom at 1.06 pct C. This rapid decrease in activation energy implies that iron at higher temperatures within the austenite range would diffuse more slowly in high carbon steels than in steels of lower carbon content. Experimental Procedure The radioactive iron used in this work was obtained from Oak Ridge National Laboratory. The unit consisted of about 1 microcurie each of Fe7 and Fe It was allowed to decay for two years. At the end of this time most of the Fe with a half-life of 46.3 days, had decayed, while most of the original Fe(half-life 2.91 years) still remained. The iron as chloride was extracted into an ether layer, using the method of Ashley and M~rray. After evaporation of the ether the iron chloride was dissolved in 250 ml of aqueous solution containing 2.4 gpl Fe. The compositions of the steels used are listed in Table I. Disks of ¾ in. diam and about ¼ in. thick were machined from these steels for use in diffusion couples. The disks were surface ground on both sides to ensure parallel opposite faces. One face of each disk was polished through 000 emery paper. Half of the prepared disks were plated with radioactive iron. For this, 1 ml of the radioactive iron

Jan 1, 1957

Jan 1, 1957

By Murray F. Hawkins

Horner1 and van Everdingen8 ave shown that the pressure drop within the wellbore, as a result of having produced the well at a constant rate q for time t, where t is sufficiently large, is: van Everdingen observed that better agreement between theory and well performance can be obtained if, instead of assuming the permeability is kc everywhere about the well, it is assumed the permeability near the well-bore is substantially reduced as a result of drilling, completion and/or production practices. In order to account for the additional pressure drop he introduced the dimensionless quantity S, the skin effect factor, so that Eq. 1 becomes: Eq. 2 might have also been obtained as follows. Assume a zone of altered permeability k, exists about the well out to a radius r and beyond that the unaltered, external permeability k. The additional pressure drop required to overcome this skin of reduced permeability may be calculated with sufficient accuracy using the incompressible flow equation; for Browns-combe and Collins1 have shown almost no difference between compressible and incompressible steady-state flow, in the vicinity of the wellbore, and the small volume of fluid in the vicinity of the wellbore makes unsteady-state mechanics unnecessary. Then. The sign of this skin pressure drop will be positive or negative depending upon whether the altered permeability k, is smaller or larger, respectively, than the external permeability k... Adding the pressure drop of Eq. 3 to Eq. 1 to find the total pressure drop: Comparing Eq. 4 with Eq. 3 it is seen that the skin effect may be defined by: be determined from pressure build-up tests1,3,4,5,6,7,8 The average permeability kavg including the altered and external permeabilities, can be determined from PI tests, and may be defined approximately on the basis of steady-state flow, as was done by Thomas' in defining the damage factor, by: The productivity ratio is the ratio of the average to the external permeability, kavg/ke or This equation shows that the productivity ratio and the skin effect are not uniquely related, because of the uncertainty in the drainage radius, and also, in many instances, the wellbore radius. Fortunately, they enter in the logarithm. The curves of Fig. I are plots of Eq. 8 for values from 100 to 50,000. The points represent the skin effects and corresponding productivity ratios from a large number of well tests, taken from Fig. 15 of Ref. 5 or Fig. 13 of Ref. 9. While some of the data

Jan 1, 1957

By B. H. Clemmons

A field method has been devised for rapid determination of heavy minerals occurring in the unconsolidatod beach and dune sands. The method has been proved practical by usage in field evaluations of several hundred beach- and dune-sand samples in the Florida area. The simple equipment required and the techniques involved are described. Other data show that the method is relatively insensitive to variations in the mineralogical content or size distribution of the mixed heavy minerals contained in the samples tested. A modification of this procedure, found to be suitable for plant use in determining the relative purity of heavy-mineral flotation concentrates, is also described. A specific application is determination of the amount of feldspar-quartz in spodumene flotation concentrates. The results of the rapid evaluation techniques closely approximate those obtained by more precise laboratory procedures.

Jan 1, 1957