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By M. A. Elliott

Diesel-powered haulage equipment has recently been tested and approved for permissibility by the Bureau of Mines for use in mining in the United States. Achievement of this advance in safety involved extensive studies, both in the testing station (2, 3, 20, 21, 22, 23, 24, 25, 26, 27)3/ and in the field 1, 4, 13, 30), of the operating characteristics of diesel engines in relation to the toe of such engines underground. The results of these studies formed the basis for establishing the requirements that should be met by diesel-powered haulage equipment approved for permissibility. Considerable interest has been manifested in the development of diesel-powered haulage equipment fur mines. The purpose of this paper is to retrace briefly the course of this development and to answer such questions as: What is the history of the use of diesel engines underground? Why has the Bureau of Mines been interested in the development of diesel-powered haulage equipment for use in mines?

Jan 1, 1953

By Robert I. Jaffee, Walter L. Finlay

IN the broad survey of the nonferrous' metallic elements contained in this book, the reader may well be impressed by the wide range of property combinations offered by the many metals and alloys the metallurgist has prepared since before Kubla Khan. The diversity is great and the overlap is considerable. It is particularly surprising, then, to find the latest structural metal new- comer designated by such extravagant terms as "Cinderella Metal," "Wonder Metal," "Miracle Metal," "The Metal of Tomorrow," "Dream Metal or Nightmare?" and "The Middleweight Champion of the Structural Metals." Of these and others, the most appropriate designation for the metal involved, titanium, appears to be that of The Middleweight Champion. Its intermediate density of 4.5 and elastic modulus of 16 million is a unique combination between the lower density and modulus of magnesium and aluminum and the higher density and modulus of copper, nickel, and iron. It is light, strong, ductile, and corrosion resistant. A chemical neighbor in group IV of the Periodic Table, zirconium, is similar to titanium in many respects but is appreciably denser, 6.5 instead of 4.5, less stiff and relatively much less abundant. On the other hand, the resistance of zirconium to acids and alkalies is better than that of titanium. Also, compensating for its higher density, lower stiffness, and somewhat lower strength level compared with titanium, zirconium has much better permeability to slow neutrons and is much more suitable as a material of construction for nuclear reactors.

Jan 1, 1953

Jan 1, 1953

For the convenience of those who are unfamilar with thermodynamics, the following brief description and explanation is given of the thermodynamical terms and methods used in this book. It must, however, be strongly emphasized that the account given below is not an introduction to chemical thermodynamics; its sole purpose is to give the reader a rough understanding of the methods used in the earlier chapters. For further information, reference must be made to the standard textbooks on chemical thermodynamics by Glasstone.

Jan 1, 1953

By Donald Carlisle

"IntroductionTHE OPINION is held by many persons outside the mining industry, and by some within it, that mine •operators customarily find it advantageous to mine •only the richer parts of orebodies and to leave behind, perhaps permanently, leaner material which could be mined only at a lesser profit. This opinion and the inference which might be drawn from it that 'gutting' of mineral resources is a common feruture• of the mining industry are prejudicial to the intertsts of the industry and deserve careful scrutiny. Oddly enough, a theory of mine economics which gives much support for the opinion was advanced first by members of the mining profession itself, has been repeated •several times in mining literature, and to my knowledge has never been adequately refoted.According to the theory, selective mining of the rich ore first on a large scale will yield substantial gains and these gains do not merely reflect the desire of 'money minded investors' for a quick return but derive from the logical application of compound interest rates and the concept of ;present value. W. O. Hotchkiss and R. D. Parks (1) illustrate the reasoning with a hypothetical example in which an orebody of 4,000,000 tons may be mined either in its entirety in forty years at $1.00 per ton profit or selectively with the recovery of only the richest half in twenty years at $1.50 per ton profit. They show that, with Hoskold rates of 4 and 8 per cent, the present value of profits from mining only the richer 2,000,000 tons exceeds the present value of profits :from mining the whole orebody by about 20 per cent."

Jan 1, 1953

By John V. Beall

IKE'S amiable expression and apparent sincerity impressed AIME members as did the theme of his talk. Cautioning against the gradually increasing power of the federal government, he said: . . . "freedom as we know it is in no greater danger from without than it is from our own lack of understanding of this creeping paralysis from within." Next February, it will be three years since he uttered these words at Annual Meeting welcoming ceremonies, but the theme was oft repeated in his winning campaign. This brush with the exalted, brief though it was, makes Washington look friendlier to many AIME members than it has for years.

Jan 1, 1953

By W. L. Crentz

Before Korea was partitioned along the 38th parallel following World War II, the coal fields of South Korea, with the possible exception of the Samchok area, were not considered important to the industrial needs or Japan or Korea. Much of the demand for electric power in South Korea was met by hydroelectric installations north of the 38th parallel. Following cessation of hostilities between Japan and the' Allied nations in 1945, hydroelectric power continued to flow into South Korea from the north until 1949, when the North Koreans severed the power lines into South Korea, thereby forcing that section of the country to depend almost entirely upon coal to generate electric power.

Jan 1, 1953

By Wilhelm Flesch

THE object of development work in the field of gasification is to find a process by which all' fuels, regardless of their individual properties, can be gasified economically. This paper describes the development of the Winkler process. The economy of the gasification process depends not only on the degree of the gasification effect but also, to a decisive extent, on the costs of fuel, production, and installations. Fig 1 shows the relation between fuel costs and gasification efficiency for various types of fuels. Since the fuel cost in the gasification of coke amounts to two thirds of the price of gas, and the thermal unit in brown coal costs only one third of what it costs in coke, it is easily seen how profitably cheap fuels can be gasified, especially if these fuels require minimum preparation and gasification is done in the vicinity of the mines. These possibilities were a great advantage of the Winkler generators, which were installed 20 years ago in the central German brown-coal fields and, at that time, were without rival for the gasification of finely divided fuels. In the Winkler generator (Fig 2), crushed and ground solid fuels were, for the first time, successfully gasified with oxygen and steam on an industrial scale. Unlike the usual processes formerly employed on an industrial scale, this gasification, which proceeds continuously in the glowing, seething fuel bed, makes only extremely low demands on the fuel. The fuel no longer has to be in lumps and abrasion-resistant, but must be capable of reaction and must be fed into the generator in a grain size of 0 to 8 mm. Brown coal or bituminous coal, or their low-temperature cokes, can be gasified in the Winkler generator. Large plants using fuels are operating on an industrial scale in Europe and in Japan. Table 1 shows the results obtained by gasifying these, fuels in Winkler generators. The thermal efficiency of gasification, which is the relation between the calorific value obtained in the gas produced and that of the fuel consumed, gives no indication of the quantity of steam generated in gasification. The generation of steam in the waste-heat boiler of the Winkler generator adequately-covers the steam consumed in gasification. To obtain effective gasification in the Winkler process, combustible mate-

Jan 1, 1953

By C. N. Stout

Square-sets go out and labor saving combination of top-slicing and sub-level caving raises tons per man hour 300 pct, cuts timber cost 50 pct to permit mining lower grade ores.

Jan 1, 1953

By Carl Wagner

AT elevated temperatures. most metals react with oxygen, sulphur, or halogen rather rapidly, although a coherent layer of the reaction product is formed and separates the two reactants from each other. The reaction proceeds, since one of the reactants or both dissolve and diffuse across the reaction product. In many cases the rate is diffusion-controlled as is indicated by the validity of the parabolic rate law of Tammann' and Pilling and Bed-worth. wott and Gurney' have suggested that diffusion processes also play an important part in the case of reduction reactions. This is confirmed by observations reported below. In general, however, the rate of reduction reactions is determined not exclusively by diffusion processes. Reduction of Silver Sulphide Above 179°C silver reacts with liquid sulphur very rapidly. Since the volume of silver sulphide is much greater than that of the equivalent amount of silver, a coherent layer of silver sulphide is formed in accordance with a rule established by Pilling and Bedworth.' According to Wagner','' silver ions and electrons migrate from the Ag-Ag,S interface across the silver sulphide layer to the Ag,S-S interface where the following chemical reaction takes place: 2 Ag +2 e + S Ag,S If silver sulphide is reduced by means of hydrogen, the equivalent volume of the reaction product, silver, is less than that of the initial substance. Accordingly, no coherent layer of silver is formed. Instead, fine filaments of silver grow from the silver sulphide surface into the ambient gas. This phenomenon has been investigated by many authors, especially by Kohlschiitter," who has also reviewed previous literature. Kohlschiitter has interpreted the observed phenomena by migration of "silver" dissolved in silver sulphide. According to Wagner,' silver ions and electrons are the migrating particles. The sequence of consecutive steps involved in the reduction of silver sulphide is shown in Fig. 1. Every- where at the silver sulphide surface, hydrogen reacts with sulphur so that excess silver ions and electrons are formed, which migrate at random until they are captured by a nucleus of metallic silver. If such a nucleus lies on the surface and material is furnished only from the base, the original nucleus is pushed outward and thus a filament grows. Removal of sulphur and formation of metallic silver may also take place at different points when silver sulphide is reduced by copper. The reaction is usually formulated as: AgL,S + 2 Cu = Cu.S + 2 Ag but the actual reaction products are silver and a solid solution of the two sulphides. Primarily, excess silver and electrons dissolved in silver sulphide are formed. After a certain degree of supersaturation has been reached, nuclei of metallic silver may form. If, however, a silver foil is in contact with the silver-sulphide phase, as is shown in Fig. 2, silver ions and electrons will migrate to the Ag,S-Ag interface where they are captured. To confirm this scheme, a composite sample, with the geometry shown in Fig. 2, was made by pressing silver sulphide tablets 0.6 cm in diam and 0.4 cm high together with a copper cylinder and a silver foil in crucibles of iron, which does not react appreciably with silver sulphide at 400°C. After heating for 3 to 7 hr at 400°C. the specimens were cut normal to the phase boundaries. It was found that the thickness of the silver foil had increased from 0.01 cm as initial value to a maximum value of 0.06 cm. In the interior of the silver sulphide tablets only traces of metallic silver were observed. These observations show clearly that silver ions and electrons may migrate over distances of several millimeters before they form metallic silver. Reduction of Cuprous Sulphide by Iron The behavior of cuprous sulphide is very similar to that of silver sulphide, since the lattices of the high temperature modifications are identical, but in Cu.S there is a variable deficit rather than an excess of metal. To investigate the displacement of copper by iron, cuprous sulphide powder covered by a copper foil was pressed in iron crucibles and heated up to 800 °C for 3 to 7 hr. The thickness of the copper foil increased from an initial value of 0.005 cm to a nlaximum value of 0.029 cm. In the interior of the

Jan 1, 1953

By C. E. Wyndham

The occurrences of manganese In Alabama were reported to be widely scattered over the northeastern section of the State, and these were examined before a development project was started.2/ The most promising and available showings were chosen for further investigation, which include 1 deposit in Goshen Valley, 6 in the Rock Run area, and 2 in the northern section of Calhoun County. The work was performed by the Bureau of Mines from July 29, 1949, to February 17, 1950. The work consisted of power auger drilling 69 holes 3-1/2 inches in diameter and totaling 2,548.4 linear feet. The accuracy of samples from auger drill holes in this type of deposit was determined by sinking two shafts a total depth of 68.17 feet, from which channel samples were cut. Sixteen rotary core holes totaling 1,048.7 linear feet were drilled with a 3-inch, double-tube core barrel. Twenty-two diamond core holes were drilled with a 2-1/8-inch, double-tube core barrel and NX diamond bit. In addition to the above drilling 220.8 cubic yards of soil and rock was excavated by hand from 403.9 linear feet of trenches and 69.7 feet of test pita. A total of 206 samples were taken and analyzed for manganese, iron, cobalt, nickel, and insoluble.

Jan 1, 1953

By Alan U. Seybolt

UNLIKE its sister elements, columbium (niobium) and tantalum, vanadium has not been available until recently in fabricated form. While Vanadium Corporation of America has offered the metal in fairly pure form for sale for many years in small lots for research purposes, this grade of vanadium has been brittle, probably because of a high oxygen content. Hence, when in 1950 the announcement1 was made that wrought vanadium was available as a commercial material, this represented a large step forward in the metallurgy of vanadium. While vanadium is generally regarded as a rare metal, data on its occurrence in the earth's crust show it to be as abundant as copper, zinc, and lead combined. Vanadium is widely distributed, but it does not seem to occur in massive deposits except in a few localities, principally in Colorado, Utah, and Arizona, where it is found in sandstone formations, and in Mina Ragra, Peru. Only in Colorado or Peru are ores mined solely for the vanadium content. Ores in the United States are principally carnotite and roscoelite; the former is of particular interest because of its uranium content. It is a uranium-potassium vanadate containing approximately 52 pct of UO2 and 18 pct of V2O5. Production in the United States during the war years averaged around 2000 tons a year, but dropped to 636 tons in 1946. In recent years, ferrovanadium has been selling for about $2.80 per pound of contained vanadium. This suggests that the price of the pure metal will never be as low as $2.80 per pound, but it could

Jan 1, 1953

By Howard Martens, Pol Duwez

IN two papers published in 1949, alloys of chromium with the refractory metals tungsten, molybdenum, tantalum, and columbium were investigated in view of their possible use as high temperature resisting materials. For the Cr-Ta system, a partial phase diagram was presented and the only intermediate phase was identified at Ta2Cr3. A phase of the same composition was also observed in the Cb-Cr system. The X-ray diffraction data presented in these papers, however, were insufficient for crystal structure determination. It is shown in the present study that the only intermediate phase in both the Ta-Cr and the Cb-Cr systems corresponds to the ideal stoichiometric ratio TaCr2, or CbCr2. Both structures are cubic, MgCu, type. At high temperature, however, TaCr2 has a hexagonal MgZn, type structure, which can be retained at room temperature by fast cooling. The alloys were prepared by melting in a helium arc furnace on a water-cooled plate. The design of the furnace was essentially the same as that described in ref. 3. Some alloys were also obtained by sintering compacts made of the mixed powders pressed at 80,000 psi. The sintering was carried on for 4 hr at 1375°C. The tantalum and columbium powders were supplied by Fansteel Metallurgical Corp., North Chicago, 111. The tantalum powder was the reagent grade, with a particle size smaller than 400 mesh and a total impurity content less than 0.1 pct. The columbium powder was smaller than 325 mesh and contained approximately 0.1 pct C and traces of Fe, Ti, and Zr. The electrolytic chromium powder from Charles Hardy, Inc., New York, was smaller than 300 mesh and contained about 0.1 pct Na, 0.05 pct Ca, and traces of Cu, Al, Mg, Si, and Co. Powder diffraction patterns were obtained with a 14.32 cm camera, using copper Ka radiation filtered through nickel foil. The powder pattern of the TaCr2 alloy obtained by sintering at 1375'C was different from that obtained on the same alloy rapidly cooled from the melt. Contrary to this result, the powder pattern of CbCr2 was the same, whether the alloy was made by sintering at 1375°C or by melting, and was similar to that of the TaCr, sintered. It was also found that the structure of the TaCr2 specimen obtained by melting was retained after heating for 4 hr at 1590°C, but transformed into the structure found in the sintered specimen after heating for 4 hr at 1375°C. Hence, the structural change of TaCr2, appears to be a reversible polymorphic transformation. CbCr2 and ToCr2 Structure, Low Temperature Form By using large scale Hull-Davey charts, the powder pattern of CbCr, and of the low temperature form of TaCr2 were readily interpreted on the basis of a face-centered cubic lattice with a parameter of approximately 6.95 kX. The indices of the reflections together with the values of sin' 0 are given in Tables I and 11. From this list of observed reflections, it appears that the (200), (600), (024), (046), and (028) reflections are missing. The lack of (h00) reflections for h 4n indicates a four-fold screw axis. The missing (Okl) spectra for k + 1 An indicate the existence of a diamond glide d. The combination of these symmetry elements can be found in the O— Fd3m space group, which is therefore the most probable one. After having determined the approximate density of TaCr, by the immersion method, the number of molecules per unit cell was calculated and found to be nearly eight. This information, added to the fact that the most probable space group is O leads to the consideration of a structure of the MgCu2 type, in which the atoms have the following positions: 8 magnesium in a and 16 copper in d. On the basis of this structure, intensities were computed by means of the usual formula: 1 cos'20 I a sin2 cos where F is the structure factor; 8, the Bragg angle: and p, the multiplicity factor. As shown in Tables I

Jan 1, 1953

By J. T. Norton, Joseph Gurland

IN spite of the extended use and high state of practical development of the cemented tungsten carbides, the structure of these alloys is still a matter of considerable controversy. The characteristic high rigidity and rupture strength of sintered compacts have been attributed to a continuous skeleton of tungsten carbide grains, formed during the sintering process. This view is based mainly on the work of Dawihl and Hinnuber,1 who reported that a sintered compact of 6 pct Co maintained its shape and some of its strength after the binder was leached out with boiling hydrochloric acid. After leaching, only 0.04 pct Co was reported to remain in the compact. They also showed that the assumed increasing discontinuity of such a skeleton, as the cobalt content is increased, could be made to account for the observed discontinuous increase of the coefficients of thermal expansion, the loss of rigidity, and the impaired cutting performance of alloys of more than 10 pct Co. Contradictory evidence was cited by Sanford and Trent,' who mentioned that a sintered compact was destroyed by reacting the binder with zinc and leaching out the resulting Zn-Co alloy. The skeleton theory also does not account for the observed change of strength of sintered compacts as a function of cobalt content. If the skeleton is responsible for the strength, the latter would be expected to decrease with increasing binder content. Actually, the strength increases and reaches a maximum around 20 pct Co. In addition, tungsten carbide is brittle and undoubtedly very notch sensitive. The highest value found in the literature for the transverse rupture strength of pure tungsten carbide prepared by sintering is 80,000 psi.3 herefore, such a skeleton does not easily account for a rupture-strength value of 300,000 psi and higher, commonly found in sint.ered tungsten carbide-cobalt compacts. In view of the conflicting data present in the literature, experiments were undertaken to determine whether the sintering of tungsten carbide-cobalt alloys leads to the formation of a carbide skeleton or whether the densification behavior and the properties of cemented compacts are consistent with a structure of isolated carbide grains in a matrix of binder metal. The specimens were prepared from powders of commercial grade. Tungsten carbide powder ranged in particle size from 0 to 5x10-4 cm. Mixtures of tungsten carbide and cobalt were ball milled in hexane for 48 hr in tungsten carbide lined mills. After milling, the specimens were pressed in a rectangular die (1x1/4x1/4 in.) at 16 tons per sq in. NO pressing lubricant was used. Sintering of the tungsten carbide-cobalt compacts was carried out in a vertical tube furnace equipped with a dilatometer (Fig. I), by means of which the change of length of the powder compacts could be followed from room temperature to 1500°C. An atmosphere of 20 pct H, 80 pct N was maintained inside the furnace. Decarburization of the samples was prevented by the presence of small rings of graphite inside the furnace tube. The temperature of the sample was measured by a platinum-platinum-rhodium thermocouple, which also was part of a temperature control system able to maintain a constant temperature within ±100C. Pure tungsten carbide compacts were prepared by sintering the carbide without binder or by evaporating the binder from sintered compacts in vacuum at 2000°C. Since complete densification of these samples was not desired, they were sintered only to 60 or 80 pct of the theoretical density of tungsten carbide. The specimens were prepared for metallographic examination by polishing with diamond powders and etching with a 10 pct solution of alkaline potassium ferricyanide. Cobalt etches light yellow and the carbide gray. The amount of porosity is exaggerated since it is difficult to avoid tearing out carbide particles, especially from incompletely sintered samples. Experimental Observations A number of specific experiments were carried out in order to study some particular aspect of the sintering problem. The details of these experiments, together with their results, are as follows: Electrolytic Leaching: The binder was removed by electrolytic leaching from sintered tungsten carbide-cobalt compacts for the purpose of determining the continuity of the carbide phase. The method used was based on the work of Cohen and coworkers4 on the electrolytic extraction of carbides from annealed steels. If the sample is made the anode, using a 10 pct hydrochloric acid solution as the electrolyte, the binder is dissolved, but the rate of solution of tungsten carbide is negligible. A current density of 0.2 amp per sq in. was applied. As shown in Fig.

Jan 1, 1953

By E. T. Hayes, A. H. Roberson, M. H. Davies

ZIRCONIUM has been produced on a pilot-plant scale for only a few years, but the potential uses have led a large number of research establishments to engage in a thorough study of the metal and its alloys. The work described in this paper is part of a cooperative project between the Bureau of Mines and the Air Materiel Command. The Zr-Cr system was one of the first investigated because of the possibilities of improving the properties at elevated temperatures, the chemical corrosion resistance, and the mechanical properties of zirconium in a manner similar to the enhancement of the properties of titanium by additions of chromium. There is no published work on the Zr-Cr system but from the similarity of the metals involved it was expected that it would be similar to the Zr-Fe' and Ti-Cr' systems. The materials used in this investigation were prepared in the Bureau of Mines laboratory at Albany, Ore. Zirconium was produced by magnesium reduction of zirconium tetrachloride, and a typical analysis is as follows: Fe, 0.06 pct; Ox, 0.08; N?, 0.01; C, 0.02; and other impurities such as Al, Pb, Ni, Ti, and Si less than 0.01 pct each. High purity chromium was prepared by treating crushed electrolytic chromium in a stream of dried and purified hydrogen." The resulting powder contained about 0.01 pct 0 and about 0.1 pct total metallic impurities. All alloys were prepared by arc-melting 50 g briquetted compacts of the desired composition in a Kroll-type" arc furnace using an inert atmosphere. The furnace was evacuated twice and backfilled with helium, which was gettered by melting a center zirconium button immediately before the alloys were melted. Alloys were remelted at least once to insure greater uniformity of composition and subsequently were annealed in vacuum at 1250°C for 48 hr. Fairly homogeneous alloys were obtained by this means; a slight loss of chromium from the surface by evaporation during the high temperature homogenization was noted. All alloys were analyzed for chromium and gave results in good agreement with the nominal composition. Spot checks on tungsten and nitrogen showed pick-up of these elements to be negligible. Over 70 alloys were prepared for use in this investigation; only the critical ones are shown in Table I. Alloys containing up to 10 pct Cr were amenable to hot working at 850°C and a number of these were sheath rolled to 1/16 in. thickness. Specimens were cut from the sheet for use as metallographic samples. For the thermal analysis a differential couple was used in conjunction with an X-Y recorder, the temperature of the specimen and the difference in ternperature between it and the standard nickel body were recorded simultaneously. Heating and cooling rates of 5°C per min were used. The sensitivity of the instrument was such that a difference in temperature between the specimen and standard equivalent to 0.1 mv produced a deflection of 1 in. on the recording chart. The chromel-alumel thermocouples were checked against a Bureau of Standards calibrated thermocouple. Melting-point determinations were made in a high vacuum induction furnace using an optical pyrometer. The pyrometer, calibrated against nickel, copper, and zirconium (iodide process) under near black body conditions, was focused on the base of a hole drilled in cylindrical samples. A North American Philips Geiger counter X-ray spectrometer was used for all diffraction studies. This instrument, in addition to supplying precise intensity measurements of planar reflections, has an added advantage in that metallographic specimens mounted in bakelite can be used directly, and this

Jan 1, 1953

By H. Kenworthy

Sulfide-ore concentrates containing cobalt, nickel, copper, lead, and iron from the operations of the National Lead Co. at. Fredericktown, Mo., were treated successfully on a laboratory scale to recover more than 90 percent of the cobalt, nickel, and copper. A cobalt -nickel-bearing, lead-copper matte., produced by the St. Joseph Lead Co. at Herculaneum, Mo., was treated to produce a lead-zinc fume, a copper sulfide concentrate, and a cobalt nickel-iron product, netting a recovery of over 75 percent of the cobalt and about 90 percent of the nickel and copper. National Lead Co. bulk concentrates were chlorinated with gaseous chlorine to form anhydrous metal chlorides and sulfur chlorides, sulfur chlorides were recovered by distillation, a high percentage of the ferric chloride was converted to ferric oxide, and the chlorinated residual metals were extracted with water. Metal ions were removed from leach liquors by pH-controlled fractional precipitation as hydroxides. Cobalt solutions "were prepared from cobaltic hydroxide, and procedures were developed to remove contaminating metal ions. Purified cobalt solutions were employed as electrolytes for deposition of high-purity cobalt.

Jan 1, 1953

During October 1947 an Authority to Prospect was granted by the Minister of Mines to lVIount Isa Mines Limited over an area of approximately 75 sq. miles to the north of Mount Isa.Application for the Authority to Prospect had been made after Zinc Corporation Limited had been granted prospecting rights over two areas, one of 1,265 acres immediately to the north of the Mount Isa Mines leases and the other of 1,960 acres adjoining the south end of Mount Isa Mines leases.METHODSAs a means of providing a cheap map of sufficient accuracy on which to plot geological features, both Mount Isa Mines Limited and Zinc Corporation Limited agreed upon aerial photographs and the two companies shared the cost of an aerial photographic survey by Adastra Airways of 130 sq. miles which covered the prospecting areas held by both companies.The photographs were on a scale of 800 ft. to I in. with 60% overlap on the north-south runs and 25% overlap east-west. A set of alternate prints enlarged to 400 ft. to 1 \in. were obtained for field work. The 400 ft. to 1 in. scale unglossed photographs (size 18 in. x 18 in.) were taken On to the field and rock outcrops, and uncorrelated structures were plotted directly on to them in red crayon pencil. The geological observations were then transferred in the office to a tracing on which accuracy of azimuth and scale was controlled by use of a photo mosaic and ground surveys.

Jan 1, 1953

By C. F. Floe, N. J. Grant, A. Joukainen

A CCORDING to Guertler,¹ Smith and Hamilton were the first to study the Cu-Ti alloy system, but because of the presence of large amounts of impurities their data are inconclusive. Hensel and Larsen² in 1930 and Kroll³ in 1931 determined the high copper end of the diagram. In 1939 Laves and Wallbaum,4 in a short summary of compound determinations in titanium binary alloys, mentioned the existence of a face-centered cubic compound, Ti2Cu, with 96 atoms per unit cell, and also a compound, TiCu3, which was said to have a deformed hexagonal close-packed structure in which ordering had been observed. The existence of a compound, TiCu, was also found but the crystal structure was not determined. Craighead, Simmons, and Eastwood determined the effect of copper on the allotropic transformation in titanium. The investigation was limited to alloys containing from 0 to 5 pct Cu, using titanium of fairly high impurity content. Experimental Procedure The methods used for determination of the diagram included metallographic examination and X-ray and thermal analyses. The system was first worked out using the higher purity "Process A" sponge titanium and oxygen-free copper. The high titanium region was next determined more accurately using iodide titanium and vacuum-melted, oxygen-free copper. Preparation of Alloys: The alloys were prepared by arc melting under prepurified helium atmos- pheres in water-cooled copper crucibles. The high purity iodide titanium alloys were prepared by melting three compositions along with a specimen of unalloyed titanium in a single charge. A multiple crucible was used which consisted of a copper plate with four cup-like depressions. The unalloyed titanium was melted first and acted as a getter for any oxygen and nitrogen in the melting chamber. Since these elements harden titanium, the hardness of the standard specimen was an index of the highest probable contamination of the alloy melts. The sponge titanium alloy melts weighed from 100 to 200 g each and the iodide titanium melts from 20 to 25 g. In order to insure greater homogeneity most of the alloys were melted, turned, and remelted twice. The larger buttons made from sponge titanium were sectioned or crushed before remelting. These alloys up to 30 pct Cu were further homogenized by forging at 925°C. They forged readily up to 20 pct Cu but numerous cracks were formed in the alloys containing from 20 to 30 pct. Above 30 pct Cu the sponge titanium alloys were homogenized by heating for 200 hr at 850°C under prepurified helium. Similarly, the iodide-grade titanium alloys containing up to 3 pct Cu were homogenized at 1000°C for 24 hr and all others at 880°C for 200 hr.

Jan 1, 1953

By Daniel Murray

"ACCIDENT PREVENTION in and around coal mines presents many problems of a type which are not encountered in any other industry. This is particularly true of the coal mines in Nova Scotia, where the underground workings are very extensive and the area of exposure to workmen is very great.Roof conditions at the coal faces and in the waste change very rapidly, almost from hour to hour, and it is at these places that the greatest dangers exist and where most mine accidents occur. It is only natural, therefore, that our attention, as far as accident prevention is concerned, should be concentrated •at the coal faces and in the waste, especially in mines where the longwall system is used in the operation •of the seam.It has been said that no hard and fast rules can be set down for timbering at the coal faces and in the waste in the coal mines in this area. We do not subscribe to this theory, however, for the following reasons:On the longwall faces in No. 18 Colliery of the Dominion Coal Company, Limited, where the 'Dosco Miner' has been in operation and where there is a very rigid system of timbering and roof supports, which is strictly followed, only one compensable accident has occurred on those faces from May 2ndJ 1950, to the time of writing this paper, February 3rd, 1953.The 'Dosco Miner' has worked on four different longwall faces in this mine and has mined and loaded some hundreds of thousands of tons of coal."

Jan 1, 1953

An account of milling "methods and costs at Mount Isa Mines Limited up to the year 1938 has been published. The present paper outlines the methods since adopted in the milling of lead-zinc ores and presents a description of the equipment now being provided for the milling of copper ore.The programme approved for the mining, milling and smelting of both lead-zinc and copper ores involves the milling 9f 50,000 tons of lead-:-zinc ore and 35,000 tons of copper ore per month.The crushed ores will be delivered to the surface from alternate levels through No. 2 Ore shaft and conveyed to their respective crude ore bins at the crushing plant. The ores will be crushed and milled in separate circuits in common buildings and the tailings will be stored on a common tailings dump. The water services to the two circuits will be separate.LEAD ZINC PLANTCrushing PlantThe crushing plant described in the previous paper was located adjacent to the Urquhart shaft. The crushing plant had grown considerably over the years by the addition of a 4ft. BY-mons shorthead crusher and a set of Traylor 72 in. x 20 in. crushing rolls and, whilst operating satisfactorily, was difficult to maintain and cramped in many places. As a satisfactory layout for the new copper crushing plant could not be made in the vicinity of the, existing plant, it was decided to construct a new plant on the western side of theconcentrator building and provide identical equipment in...

Jan 1, 1953