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By J. T. Norton, A. L. Mowry

S. J. SINDEBAND*—(1) Discussing the properties of the powders used, Mr. Rostoker mentioned a silicon powder as being between 150 and 325 mesh. We always had much difficulty in measuring particle size of silicon powder by screen analysis, because of its tendency to agglomerate. I would be interested in the method used to measure these particle sizes. (2) Mr. Rostoker maintains that the measurement of magnetic properties is more accurate in determining complete homogenization of an alloy, than is the X ray diffraction technique. I wonder whether this is really true. Even when diffusion is complete, magnetic properties will change during continuation of the heat treatment, due to change in density and pore shapes, as has been demonstrated by Mr. Rostoker himself. Which effect is faster, the diffusion of the alloy components or the attainment of final density, will, in my opinion, depend very much on initial material and sintering conditions used. For magnetic applications, of course, the magnetic measurements are most suited for determining the point at which equilibrium conditions are reached. (3) I was glad to see that Mr. Rostoker had used sample sizes which are similar to those I had used previously, and I believe that ring samples of about 2 in. od will become more or less standard samples for the determination of magnetic properties of powder metallurgy products. I should like to ask how the density was changed for the samples on which the effect of porosity was investi- gated, and, further, why the sintering temperature used for this series of experiments was so low. It is somewhat surprising that a 24-hr treatment at 850°C acts so much more to spheroidize the pores than a treatment for 1 hr at 1100°C. But the effect seems to be indisputable. I have made an investigation of the influence of sintering temperature for longer times on the maximum permeabilities of iron powder compacts which was presented at the International Powder Metallurgy Conference in Graz, in 1948, and I hope that these results will be published here within a short time. The results of this investigation are confirmed by Mr. Rostoker's findings that the change of time from 1 to 24 hr changes the permeability behavior considerably in the direction as indicated by Polder and Van Santen for spheroidiza-tion of pores. I do not quite understand Mr. Rostoker's explanation of the influ-

Jan 1, 1950

By Edward Hart

Having occasion several years since to make ferrous sulphide, I attempted to do so by fusing a mixture of coal-brasses (FeS2) and dried ferrous sulphate. A very nice-looking sulphide was obtained; but on attempting to use it, I found that it was insoluble in dilute hydrochloric and sulphuric acids. The subject was laid aside at the time, but has since been taken up; and some curious results have been obtained, which I believe are new. I have made the material by all of the following methods and the product seems to be pretty much the same, however obtained : (a) FeS2 heated to fusion. (b) FeS2, and FeSO4 heated to fusion. (c) FeS2, and Fe2O3 heated to fusion. (d) FeS2, and FeCO3, heated to fusion. (e) FeSO4, and S heated to fusion. (f) Fe2O3 and S heated to fusion. Obtained in this way the mass after cooling breaks easily and is very nearly black in color. On the upper surface of the fused cake the color is generally reddish or brownish black. When this is treated with dilute sulphuric or hydrochloric acid, it refuses to dissolve; but if touched with the point of a file or any piece of wrought-iron, solution of the sulphide takes place with the evolution of sulphuretted hydrogen. If the iron is removed the evolution of gas ceases, and only begins again when the iron is again brought into contact with the fused sulphide. The same thing happens if the iron is connected with the sulphide by means of a platinum wire. But in all the samples of fused sulphide I have obtained, if the iron is allowed to remain in contact with the sulphide for a certain time (which varies with different samples of the fused sulphide) and is then removed, solution of the sulphide continues. Zinc, tin, and magnesium have the same effect as iron. In hydrochloric acid aluminium acts more rapidly even than iron. In sulphuric acid it has little if any effect. Copper in HCl, when brought in contact with the fused sulphide, dissolves quietly without evolution of gas. The solution of copper chloride formed becomes,as it flows down over the sulphide, converted into copper sulphide.

Jan 1, 1887

By David Reger

LITTLE new oil was found in West Virginia, during 1923, but there were important discoveries of gas. Most of the large oil producers have contented themselves with pumping old wells or in drilling only enough new wells in defined territory to maintain a fairly constant production, the attitude being that no, profit is made in producing high-grade oil at a low price and that an eventual loss is sustained by draining the reserves of a limited commodity that, at some more favorable time, will be of much value. The representative of one large company said: "We have done nothing but pump old wells during 1923 and we have made no plans for 1924." Careful attention to producing wells has been the rule, there having been few abandonments; the belief is prevalent that small wells will eventually become profitable under more favorable marketing conditions. In natural gas, the opposite point of view prevails. Because of the vast capabilities of the state for producing gas, its output being ahead of all others, great systems of transportation and distribution into the markets of four adjoining states have been built and a demand has been created that no present, or apparently potential, production can satisfy. This demand has become so great that large distributing companies not only discourage new applications for service but advise old customers to install coal furnaces for auxiliary fuel; some have requested public-service commissions to grant higher 'rates against large industrial consumers than those allowed for domestic heating. The response to this known market has been a rapid increase in price, both at the well mouth and at the door of the ultimate consumer, and the industry has become so stable that the only uncertainty, or hazard, appears to be the question of the presence of gas in fair quantity in a given territory under consideration. Several oil companies have now forsaken their policy of selling gas, wells outright when drilled and ;have organized gas departments to drill for gas and to dispose of the daily output by meter to distributing corporations. With such companies and with other producers whose interest is chiefly gas, the year has been busy and profitable. Some new territory of apparently large value has been proved and deeper producing sands in old fields have been tapped.

Jan 3, 1924

By C. M. Haight

THE mine blacksmith and drill-steel sharpening shop at the Franklin mine of the New Jersey Zinc Co. is on the surface, adjoining the main shaft. It is a brick building, 51 by 30 ft. inside dimensions, with a corrugated iron roof and concrete floor. About two-thirds of the steels used are brought up through the main shaft; the remainder through two auxiliary shafts. The latter are carried to the shop by team or truck. At each shaft sufficiently large stocks of sharp drills of various types are kept to replace all the dull steels that may be sent up; while at the shop enough sharp drills are kept to replace the dull steels in. the stocks kept at the auxiliary shafts. Though this entails keeping a larger number of drill steels in service than might be required by other methods, there is less hurry in the sharpening shop and the steels have a longer period of rest. If a rest from use enables steel to recover from fatigue strains, this method secures that rest. The forms shown in Fig. 1 are supplied to each shift boss in books of 100. These are used to requisition sharp drills from the shaft stocks and enable the men at the tops of the shafts to sort out the required sizes and to have them ready to be sent to the various shaft stations. At one of the auxiliary shafts, the dull drills are placed on a platform from which they are dumped into the body of the wagon that takes them to the shop.

Jan 2, 1926

By H. Y. Bassett

THIS paper attempts to show the various major operations used in nonferrous tube mills and does not necessarily represent the current practices at the two plants of the Wolverine Tube Div., of Calumet and Hecla Consolidated Copper Co. Inc. The operations now utilized in the production of tubing are quite varied and show the continual interest and advance metallurgically and mechanically to produce the best quality at the lowest cost. Naturally, any advance or lowering of cost is dependent on large production runs, which mean longer machine running time with maximum worker productivity. Standardization of tube sizes and elimination of unnecessary alloys are therefore very necessary, otherwise the development of costly new production machines would be of little benefit to the consumer as a whole. It should be noted that in such a short presentation it is impossible to describe in any detail the major operations. The short descriptions, it is hoped, will enable all who are interested to obtain a general idea of present, day practices in the copper tube producing field. Fig. I is a flowchart or sequence of operations showing the steps usually employed in tube production. RAW MATERIALS Quality starts with the raw material, and it is absolutely necessary that raw material be controlled and held to rigid specifications. Little need be said, however, regarding the raw materials for the casting of bars or billets, as the material always is purchased and checked against the various governing A.S.T.M. specifications. CASTING Casting, as is indicated in Fig. I, is quite varied and for convenience can be classified into two groups: The casting of solid billets, and the casting of hollow tubes, each of which is the base for subsequent operations. In the melting of the raw materials various types of furnaces are used, and the selection of any one is dependent on many factors outside the scope of this paper. However, as of general interest, a short description will be made of each. Induction Furnace (Low Frequency) This is popular in the melting of copper-base alloys, Fig. 2. In the induction furnace the principle of an inefficient transformer is used for the production of the necessary melting heat. The primary coil is.arranged around a transformer core made of high permeability silicon steel sheet. The secondary circuit is through a melting channel around the primary coil and opens into a hearth which contains the main charge. The heat is generated only in the melting channel, but because of the stirring action there is a constant flow of metal around the channel, which when mixing with the charge causes very rapid melting. The volatilization losses are very low as the furnace atmosphere above the charge is heated only by the heat from the melting metal. The stirring action, however, makes the use of any slag cover difficult. Such furnaces- must be started with molten

Jan 1, 1951

By J. H. Klepinger, C. W. Goodale

I. Introduction....................567 II. Character oF the OrE................568 III. Old FluE System..................572 IV. Tests on Old FLUE System..............575 1. Aspiration Tests................. 575 2. Tests with Steel Settling Chamber........... 575 3. Test with Experimental Brick Flue........... 583 4. Testa on Blast Furnace Geses............. 591 V. Design of New FluE System.............. 597 VI. Main Dust Chamber................. 605 VII. Some DetailS of Construction ............. 609 VIII. THE Chimney.................... 616 IX. Operation of New FluE System............. 624 X. Temperatures and DraFTS............... 630 XI. Velocities and Volumes................ 632 XII. TeStS on the New FluE System............. 637 XIII. Conclusion..................... 643 I. Introduction. In the summer of 1909 the Boston & Montana reduction department of the Anaconda Copper Mining Co. completed a new flue system, at a cost of about $1,100,000, and as this includes the largest and highest chimney in the world, and some new features of flue construction, a description will be of interest. At the Spokane meeting of the Institute in September, 1909, a brief mention was made of this flue system, in discussing Mr. Brunton's presidential paper on the Progress of Metallurgy in the West, and a promise was given that when a long enough time had elapsed, so that operating results could be given, a paper would be offered. The smelting plant includes blast furnaces, MacDougall roasters, gas-fired reverberatories, and converters.

Jan 1, 1914

By Robert Forsyth

As the latest plant on a large scale, the new Bessemer works of the North Chicago Rolling Mill Company, at South Chicago, presents some features of interest to steel-makers, I have ventured to lay before the Institute a short description of that plant, and some* remarks upon the practice there. At the time the South Chicago works were designed the adoption of the basic process in this country seemed imminent. Experience in Europe had demonstrated the perfect success of the process technically, and the question of its commercial value was one which, for any particular works, would have to be settled by its special advantages for procuring the necessary ores and basic materials. Under the circumstances, it was thought best at South Chicago to so arrange the plant as to allow the introdnction of the basic whenever it became advisable, and to make such other changes from the standard type of Bessemer plant as the state of the art seemed to demand and to foreshadow. As the use of metal direct from the blast furnace, while generally condemned by experts here, was in such successful practice in Europe (particularly in connection with the basic process), there was no doubt about its feasibility, while its economy in fuel and labor made it especially attractive to the Western manufacturer. It was accordingly decided to build a direct-metal plant adapted to the basic process. The ingots made were to be rolled into rails at one heat, and were to be of such size (12 inches square and long enough for three and four rails) as to be readily and quickly handled by the rolling machinery proposed. This small size of ingots, and the large number cast from each heat of 10 tons, made it necessary to provide a good deal of room in the casting-pit—much more than in any previons plant—and to put down extra facilities for handling ingots. To meet the delays incident to the basic process—to insure that one vessel should be always blowing if necessary, and to provide opportunity for current repairs to linings, etc.—it was decided that three vessels should be used, and, to properly concentrate the work of

Jan 1, 1884

By K. K. Clark, W. H. Somerton

The feasibility of reducing pressures needed to fracture formations by heating the borehole intensively has been investigated on a laboratory scale. Reductions in fracture pressures of heated Bandera, Berea and Boise sandstone cores were observed at various confining pressures, simulating reservoir stress conditions to a depth of 5,000 ft. Both permeable and impermeable borehole boundary conditions were tested. Three heating conditions were used in the tests. One group of samples was heated in a furnace to a temperature of 600C, cooled to room temperature., and then tested for fracture pressures. Two other groups of samples were heated with a borehole heater to maximum borehole wall temperatures of 625 and 792C, then cooled and tested. In all cases, heated samples showed substantial reductions in fracture pressures compared to unheated samples. The higher temperature borehole heated samples showed the greatest reduction, amounting to 70 per cent in the extreme case. In actual application to wells, it was concluded that fracture pressures may be reduced by 20 to 50 per cent by intensive borehole heating before fracturing. INTRODUCTION Hydraulic fracturing of oil and gas wells is an accepted and effective technique for increasing well productivity in many areas, but is notoriously unsuccessful in other areas. The technique becomes less interesting for production stimulation purposes when excessive fracture pressures are necessary. Formations which do fracture but require high pressures, probably form horizontal fractures. There is good evidence to indicate that some formations do not fracture at all, but yield plastically under high pressure. Thus, any technique which will make formations easier to fracture or will reduce fracture pressures is potentially interesting to petroleum producers. Horizontal fractures generally occur in planes of weakness, such as bedding planes, and at pressures equaling or exceeding the effective overburden stress. In the unusual case where planes of weakness do not exist, a slightly higher pressure must be applied to overcome the tensile strength of the rock. In general, high fluid-loss fracturing fluids are conducive to the formation of horizontal fractures.1 Vertical fractures, when they do occur, are initiated at pressures generally lower than overburden pressure and are favored by low fluid-loss fracturing fluids or impermeable boreholes. The pressure necessary to create a vertical fracture in an impermeable, elastic medium can be predicted from the so-called "thick-walled cylinder" equation: Pf = 2 or+ st.............(1) where pf = fracture pressure or = radial stress st = tensile strength of medium. This equation indicates that to fracture it is necessary to overcome a tangential compressive stress, induced by and equal to two times the radial confining stress, plus the tensile strength of the medium. If the above equation held strictly true for rocks, very little could be done to reduce fracture pressure. The tensile strength of the rock might be reduced somewhat, but any change in st would be small compared to the magnitude of the tangential stress at reasonable subsurface depths. Laboratory tests have shown that actual fracture pressures exceed values predicted from Eq. 1 by factors of 1.4 to 28.6.1,2 Eq. 1 thus does not properly describe the

Jan 1, 1966

By W. A. Foster

NINETY years after the Riddle nickel deposit N was discovered in Oregon in 1864, Hanna Coal & Ore Corp. began mining operations. Until 1954 much prospecting and preliminary development work had been done on the property, but no ore had been shipped other than for metallurgical testing. The deposit is being explored by churn drilling and trenching, and a few test shafts have been put down for the purpose of studying the ore in place, determining volume and moisture factors, and gathering bulk samples for pilot plant and smelter tests. In churn drilling, 6-in. casing is driven down 2 or 3 ft behind the drill bit and bottomed at each 5-ft interval. All the sludge for each cased 5-ft interval is dumped through a splitter and one eighth is saved and analyzed. Drillholes are stopped after going through the ore zone and penetrating fresh peridotite in which the nickel content is less than 0.5 pct.

Jan 8, 1957

By Robert S. Archer, L. W. Kempf

It is now well known that the structure of aluminum-silicon alloys can be refined in a rather remarkable manner, with consequent improvement of physical properties, by certain treatments applied to the molten metal shortly before casting. The differences between the treated and the untreated alloys are so marked that special terms are used to distinguish them, the untreated alloys being referred to as "normal" and the treated alloys as "modified." The first practical method of accomplishing this result was that of A. Pacz,1 which consists in treating the molten metal with a salt flux of which the active ingredient is sodium fluoride. The result can also be brought about, and in a more economical manner, by the addition of small quantities of metallic sodium (or potassium) to the molten alloy shortly before casting.2 The action of the Pacz flux evidently consists essentially in the production of free sodium by the reaction of sodium fluoride with aluminum. The changing of a normal alloy to a modified alloy is referred to as "modification" and any process for accomplishing this result is a "modifying" process. Modified aluminum-silicon alloys were introduced several years ago, and it has been demonstrated both in the laboratory and in commercial practice that it is no simple matter to produce castings having the maximum or nearly the maximum properties which under favorable circumstances can be obtained. The alloys are rather sensitive to small changes in chemical composition, and the modifying process must be carried out in a very particular manner to obtain the best results. Extensive experimental work has been carried out in the laboratories of the Aluminum Co. of America with the object of determining the conditions that must be observed to make these alloys of the greatest possible value. It was necessary to learn how to control the modifying process

Jan 1, 1926

By R. V. Ramani, C. J. Bise

The potential of deep-mineable coal reserves in the western United States for meeting future energy needs has been recognized for quite some time. However, two of the major constraints tending to limit the development of these underground reserves are the great thicknesses of the coal seams encountered and their high pitch. Although new mining methods may need to be developed to recover these reserves, at least in the short-term the industry has to incorporate presently available equipment not originally designed for thick-seam mining. The purpose of this paper is to present an analysis of the various equipment in use today and their possible application to thick-seam mining. The paper also addresses various ground control and safety considerations unique to thick-seam extraction.

Jan 1, 1984

By Paul D. Merica, R. G. Waltenberg

Although nickel was discovered and isolated as early as 1750 and its valuable properties recognized, many years passed before it was used commercially for wire, sheet, rods, etc., in the pure form. This was due partly to its high cost at that time and partly to the fact that it was not possible to refine and cast nickel into ingots sufficiently malleable to be amenable to the usual forging, rolling, or drawing processes. So remarkable was this fact, and so different from the experience at that time with metals such as copper and iron, that it has left its impress on the nomenclature within the nickel industry. To this day, furnace-cast nickel produced in such a manner as to be suitable for rolling and forging is called malleable nickel to distinguish it from the ordinary pig and shot nickel of commerce. In 1878, the firm of Jos. Wharton, of Philadelphia (which later became The American Nickel Works, a constituent of The International Nickel Co.) exhibited at the Paris Exhibition specimens of rolled pure nickel strip and of drawn nickel wire. About this time, there was considerable activity in the study of the refining of nickel and several methods were described, some of which were patented, for the production of furnace-cast malleable nickel including the use of manganese (Boed-dicker,1 Selve and Lotter2), the use of potassium permanganate (Berns-dorfer Metallwarenfabrik3) and the use of phosphorus (Garnier4). By far the most efficient method was discovered by Th. Fleitmann in 1879;5 it consisted in adding to the molten nickel, just before pouring the castings, from 0.05 to 0.125 per cent. of metallic magnesium. This soon became the recognized final malleableizing treatment for furnace-cast nickel.

Jan 1, 1925

By J. R. Finlay

The Cæur d'Alene silver-lead mining district of northern Idaho is probably best known to the general public as a seat of labor-troubles. So far as the writer is aware, little has been written and little is known about its geology and resources. People interested in lead-smelting are, of course, cognizant of the economic importance of the region, but they have not communicated much of their knowledge to the public. Exact figures as to the total output of the district are not obtainable, but the following estimates, covering the entire output of the 15 years during which the mines have been operated, are believed to be approximately correct: Group of Mines. Product. Wardner Group, including the Bunker Hill and Sul livan, Empire State-Idaho, Last Chance, Sierra Nevada, bur d'Alene Development Co... . $17,500,000 Cafion Creek Group, including the Gem, Frisco Con solidated, Granite, Standard, Mammoth, Hecla, Tiger-Poorman, Custer and Bell,.... 35,000,000 Mullan Group, including the Morning, You Like and Gold Hunter,........7,500,000 $60,000,000 This output covers the period of discovery and early struggles, and several periods of stagnation caused by strikes and other serious labor-troubles. In 1900 the output of the district was fully $10,000,000, and this figure would have been considerably increased in 1901 had not a curtailment of production been forced by the condition of the lead-market. In 1901 the product was about 150,000 tons of concentrates, with a gross. value of $8,250,000.

Jan 1, 1903

By B. A. Rogers

ACCORDING to petrographic investigations, 1-4 cooled steel furnace slags contain a number of substances that have been shown to be ferro-magnetic5,6 and hence capable of undergoing appreciable changes of susceptibility with temperature. Since any alteration of the suscepti-bility of a constituent affects the average susceptibility of the sample, information concerning the nature of the substance should be deducible from its magnetic behavior. The possibility of obtaining information concerning slags in this way led to the construction of the apparatus to be described. FUNDAMENTAL PRINCIPLES OF APPARATUS The most convenient method of observing changes in mass suscepti-bility? with temperature is the one employed by Curie7 in his original investigation of the changes in magnetic properties of substances at elevated temperatures. As the method has been described frequently in the literature and in textbooks, only a brief review of the fundamental principles need be given here, but the particular arrangements used in the present work require a more detailed description.

Jan 1, 1939

By D. A. Belforti, M. P. Lepie

Spectroscopically pure copper was melted on sapphire plaques in a zydrogen atmosphere. The surface tension of the liquid metal was determined using the sessile drop technique. Measurements were made by direct observation with the aid of a specially const,mcted telescope. The value obtained, 1268 dynes per cm, is compared to that found in the literature. THERE is at this time considerable interest in the use of ceramics for vacuum tubes. The crystalline material is superior to the more conventional glass in mechanical strength, chemical inertness, dielectric properties, ability to withstand high temperatures, and so forth. However, ceramics are much more difficult to seal hermetically with metals than are the glasses. For this reason an investigation was undertaken to determine the wetting and adhesion of metals to ceramics. The sessile drop technique offers a convenient means at elevated temperatures for measuring liquid surface tension, wetting angle, density, spread- ing coefficient, and work of adhesion. Thus, from the contour of a drop of liquid at rest on a solid surface one can obtain a quantitative evaluation of the degree to which the two substances will bond. To this end a special apparatus was constructed so that various molten metals could be observed. Standardization of the apparatus was done initially by measuring the surface tension of copper since this is well documented in the metallurgy literature. Although there are many methods available for the measurement of surface energy,'+ the sessile drop technique has been used most extensively for molten metals and ceramics.5"' Fig. 1 illustrates the dimensions to be measured. From these values, the surface tension of the liquid can be obtained using the Bashforth and bdams' equation and tables.

Jan 1, 1963

By E. P. Abrahamson II

The effect of transition element binary solid-solution additions upon the recrystallization temperature of vanadium has been investigated. Cr, Fe, Co, Ni, Mo, Ru, Rh, Os, and IY lower the recrystallization temperature, while Ti, Mn, Zr, Cb, Pd, Hf, Ta, W, Re, and Pt raise it. The majority of elements have their greatest effect in less than 0.15 at. pet. Both the rate of change of recrystallization temperature with atomic percent solute and the limit of initial linearity are found to Correlate with the free atom grozdnd state outer electron configuration of the sollte element. THE work of Abrahamson and Grant1 and Abraham-son and Blakeney2 has shown that the solute's elec- tron configuration appears to be a prime determinant of both brittle-to-ductile transition and recrystallization temperature in dilute binary alloys. It has also been shown by Abrahamson3 that the limit of linearity, i.e., the limit of initial linear change of recrystallization temperature with atomic percent solute, is also a function of the electron configuration of the solute in iron base alloys. Because of the systematic nature of the solute electron configuration correlation, it is to be expected that some systematic variation might be observed upon changing the solvent. Thus, this study of recrystallization in vanadium base alloys is the first of a series aimed at defining the role played by the electron configuration of solute in determining the recrystallization characteristics of dilute transitional alloys. PROCEDURE All alloys were made using 99.8 pct V containing 0.011 C, 0.024 N, 0.08 0, 0.006 H, 0.035 Ta, and

Jan 1, 1962

By Reuel A. Cochrane, Harry H. Angst

The successful exploitation by opencut methods of the low-grade porphyry copper deposits is due to the economical handling of large tonnages. Large tonnages are possible only if the rock material is broken so that the large power shovels can operate with minimum delays. This is particularly true at the New Cornelia mine, where the dense, hard, tough rock material creates problems not encountered in most of the porphyry copper mines. The introduction of churn drills at the New Cornelia for primary drilling, in 1936, necessitated a complete change in the methods of breaking ground as formerly air drills had been used. The blasting operations are of particular interest because of the handling of great quantities of high explosives in safely and efficiently fragmenting the hard rock material. Rock Formations At the New Cornelia mine the rocks are quartz monzonite with a diorite border facies intruding a rhyolitic series. Overlying these formations is a fanglomerate formation composed of boulders of monzonite, diorite, rhyolite, and other types of rock of unknown derivation. (The word "fanglomerate" is used in this paper in referring to the local conglomerate type of rock formations.) The ore body is approximately 4800 ft. long and 2800 ft. wide, and is of the disseminated type. Mineralization occurs principally in the quartz monzonite and to some extent in the adjacent diorite and rhyolite. The principal ore minerals are chalcopyrite, bornite, and a small amount of chalcocite. Over a considerable area the quartz monzonite is extremely hard and siliceous in character, owing to pegmatitic zones of alteration. The hardness of the ground depends on the intensity of the silicification. In a small area in the pit, the monzonite contains an abundance of pyrite accompanied by sericitization and is soft and easily fragmented. This is true also in the remaining oxidized portion of the ore body. The diorite and rhyolite formations, like the monzonite, vary from extremely hard to very soft material, but on the whole are easier to fragment than the monzonite. Jointing is prevalent in all the rock formations and plays an important role in the blasting efficiencies. In the fanglomerate formation, numerous well-defined joints, widely spaced, tend to make the ground blocky when blasted. This is a deterrent to good fragmentation. In the other rocks the joints are more numerous and are closely spaced, except in localized areas where the formations are extremely hard. These descriptions indicate that the lowest blasting efficiency will be obtained in the harder formations, from which the major portion of the mine production is obtained; namely, the monzonite and rhyolite. All rock formations mined at the New Cornelia pit are so hard that excavation

Jan 1, 1943

By Harry H. Angst, Reuel A. Cochrane

The successful exploitation by opencut methods of the low-grade porphyry copper deposits is due to the economical handling of large tonnages. Large tonnages are possible only if the rock material is broken so that the large power shovels can operate with minimum delays. This is particularly true at the New Cornelia mine, where the dense, hard, tough rock material creates problems not encountered in most of the porphyry copper mines. The introduction of churn drills at the New Cornelia for primary drilling, in 1936, necessitated a complete change in the methods of breaking ground as formerly air drills had been used. The blasting operations are of particular interest because of the handling of great quantities of high explosives in safely and efficiently fragmenting the hard rock material. Rock Formations At the New Cornelia mine the rocks are quartz monzonite with a diorite border facies intruding a rhyolitic series. Overlying these formations is a fanglomerate formation composed of boulders of monzonite, diorite, rhyolite, and other types of rock of unknown derivation. (The word "fanglomerate" is used in this paper in referring to the local conglomerate type of rock formations.) The ore body is approximately 4800 ft. long and 2800 ft. wide, and is of the disseminated type. Mineralization occurs principally in the quartz monzonite and to some extent in the adjacent diorite and rhyolite. The principal ore minerals are chalcopyrite, bornite, and a small amount of chalcocite. Over a considerable area the quartz monzonite is extremely hard and siliceous in character, owing to pegmatitic zones of alteration. The hardness of the ground depends on the intensity of the silicification. In a small area in the pit, the monzonite contains an abundance of pyrite accompanied by sericitization and is soft and easily fragmented. This is true also in the remaining oxidized portion of the ore body. The diorite and rhyolite formations, like the monzonite, vary from extremely hard to very soft material, but on the whole are easier to fragment than the monzonite. Jointing is prevalent in all the rock formations and plays an important role in the blasting efficiencies. In the fanglomerate formation, numerous well-defined joints, widely spaced, tend to make the ground blocky when blasted. This is a deterrent to good fragmentation. In the other rocks the joints are more numerous and are closely spaced, except in localized areas where the formations are extremely hard. These descriptions indicate that the lowest blasting efficiency will be obtained in the harder formations, from which the major portion of the mine production is obtained; namely, the monzonite and rhyolite. All rock formations mined at the New Cornelia pit are so hard that excavation

Jan 1, 1943

By S. Harries Daddow

IN order to get an idea as to the strength of steel rails, it will be well to review the tests to which iron rails have been subjected. In England, Mr. Ashcroft found that the best 80 pound rails broke under a 300 pound weight, falling 15 feet. In Germany the Society of Railway tyfanage1-s determined 011 and have long applied a test of 1000 pounds falling 101/2 feet, as the standard which all first-class iron rails must reach. In this country no inspection nor test is applied, but tests made show that iron rails fro; our most reliable makers, break under a G foot fall of a 1500 pound drop as an extreme test, most of those tested breaking under a far less test; some breaking with less than a 3 foot fall of the same weight. Everywhere where steel has been used, engineers have come to the conclusion that some test is required to show the regularity and strength of the product. As compared with iron, the tests which steel will stand are wonderful. After numerous experiments partially based on the experience of the rail-mill at Graz, belonging to the Southern Railway of Austria, the Society of German Railway Managers fixed upon a test of 2000 pounds falling 138 feet. They found that this test represented the steel which suited their necessities, and also found that with steel of otherwise average purity, this test represented about one-half per cent. of carbon, and made it a rule to take no steel containing under three-tenths of a per cent. of carbon, because it was too soft. They expressed a hope that a harder steel could soon be made tough enough to stand the same test. I n England, a test was adopted of 2240 pounds, falling 15 to 17 feet on the rail on heavy bearings. This test has been found satisfactory under heavy traffic on average road-beds, and has been invariablyPILLAR of coal, which are designed and left in our mines as the means of supporting the overlying strata of our coal-beds, and securing protection to the miner, are not only insufficient for these purposes, but the most objectionable means of providing the desired security to life and property. Though such pillars are left at a great sacrifice to the owners of collieries and mineral lands, loss to the resources of the commonwealth, and ultimate privation to the public, they defeat the very ends for which they are designed, and not only do not secure life and property, but are as fatal to the one as ruinous to the other. Propositions.-It is eminently desirable that the resources of the Common wealth-particularly our mineral wealth in anthracite coal, which is limited-should be carefully utilized and made available, not only to ourselves but our posterity. Yet, speaking as an anthracite miner, we are wasting our resources of coal with a recklessness which will bring ruin in the end, unless checked, not only to the iron manufacturing interests of the East, whose chief protection, in competition with the iron-masters of the interior, lies in a cheap and abundant supply of anthracite furnace fuel, but to the best interests of the State. It is, consequently, not only desirable, but necessary, that we should realize every ton of coal from each colliery, and every acre of coal area, in order that our resources may not be wasted at present, to breed want in the future, and to realize the greatest present benefit to the mine, the miner, and the public. It is not possible, however, to secure these ends, if we continue to leave, as we do at present, from one-third to one-half our resources in anthracite as pillars in our mines. But our sad bills of mortality, our abandoned collieries, and our yawning mountain-sides, present ample evidence that even this enormous waste of coal, though left for the purpose of protecting life and property, is as totally inade-

By Arthur Phillips, C. H. Mathewson

During the past year considerable work dealing with the mechanical properties and microstructure following the anneal under uniform condi-tions of certain types of commercial rolled brass has been done in this laboratory. Since these experiments were conducted with the active cooperation of the Bridgeport Brass Co., involving free use of its product, and have thus furnished information which is characteristic of some of its special mixtures, full publication of the numerical relationships and comparative results encountered does not seem justifiable. Some of the more general features of this work are, however, available and it is our present purpose to use the material in question, along with some results of special tests, in discussing the characteristics of recrystallization as related to the degree of hardening by strain and the ordinary annealing variables. We desire to make acknowledgment of the many courtesies extended by Mr. Charles Ferry, Metallurgist of the Bridgeport Brass Co., and the value of his cooperation, which has greatly stimulated the study of brass in this laboratory. A clear and systematic presentation of the principal relations between temperature and time of anneal, the changing physical properties and microstructure and the degree of previous reduction by cold-rolling, was first made, in the case of rolled brass and copper, by the French engineer, C. Grard,' in 1909, although much fragmentary information of this general character had appeared earlier and the main facts involved were undoubtedly known to many brass specialists through their own private research. From this work, it appears that in the cartridge mixture (67 per cent. copper, 33 per cent. zinc) the properties imparted by cold-working within the limits, 13 to 75 per cent, reduction of area by rolling Original Area — Final Area 0.13 to 0.75), are not affected by anneal- Original Area " ing for a 50-min. period at any temperature below 200°C. At or in the

Jan 1, 1916