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By W. A. Lang, K. C. Gilbart, E. Stansfield

It has long been known that coal is unstable and oxidizes in air, even at ordinary atmospheric temperatures; also, that such oxidation affects the analysis of coal. Nevertheless little or no precaution is taken to prevent oxidation in the ordinary methods of analysis, and the possibility of error due to oxidation is sometimes ignored even in researches on coal. Although the general nature of coal oxidation is well known, and many workers have made careful studies of the rate of oxidation of different types of coal exposed to oxygen at different temperatures, yet the amount of oxidation coals undergo in the ordinary process of analysis, and its influence on the determined analysis, is not well known, and the published data are widely scattered through the literature. This paper is a collection, from this laboratory, of data that bear on the subject, together with a brief summary of three methods employed here to evaluate the oxidizabil-ity of coal. The post-Carboniferous coals of Alberta range all the way from anthracite down to lignite. As some of them are notably susceptible to oxidation, the necessity for care was early forced upon our attention, and oxidation has been reduced either by the removal of air with a vacuum pump or by the displacement of air with natural gas (methane). The two routine analytical operations most liable to involve oxidation are the preliminary, partial drying of the crushed coal (called air-drying) and the determination of moisture. The first is a prolonged operation on coarse coal at ordinary temperatures, and the second a short treatment on powdered coal at higher temperatures. Oxidation also occurs in coal samples stored in ordinary sample bottles. In order to gain information for this study, determinations were recently carried out on the same samples in air, in natural gas, and in vacuo. Sixteen coals were tested; three would be classed in the United States as coking bituminous coals, two as noncoking, nonslacking, bituminous coals, and the rest as subbituminous. Table 1 gives typical analyses of these coals as mined.

Jan 1, 1934

By Charles MacDowell

Up to 1909 the American public had little knowledge of, or interest in, potash. Some remembered that it had to do with soft soap and sore throat, but further they knew not. In 1909-10, the German-American potash war, and the publicity attending hostilities, brought home to America the knowledge that potash was an important article of commerce; that Germany monopolized its production and distribution, and exercised all the prerogatives attending complete control. The present war, with its transportation embargo, has again directed attention to Germany's strength as a potash producer and her present unfortunate situation as a distributor. As a consequence, the search for potash takes on new life and it again becomes a subject of general interest. My first knowledge of potash came from a study of the German potash exhibit at the World's Fair in 1893. This investigation led to the recommendation that Armour & Co. engage in the manufacture of commercial fertilizers and the fertilizer branch was organized early in 1894. From then to now "potash" has been a live subject. Two and eight-tenths per cent. of the earth's crust consists of potassium oxide. It is an important constituent of feldspar, granite, and other igneous rocks. Potash is valuable commercially in a water-soluble form. In igneous rocks it is locked in so tight that it is of little value and no utilization in a commercial way has been made of these insoluble forms. Potash in water-soluble form is found in large deposits in Germany; in smaller deposits in Austria and Spain; and in brines in some of our Western arid basins. The deposits in Germany, Austria, and Spain are concentrations from sea waters containing potash derived from the decomposition of potash-bearing rocks.

Jan 2, 1915

By E. M. Murphy

Eight years ago the Hecla mine, a lead-silver producer, situated at Burke, Idaho, was producing ore from but two levels, the 300- and the 600-ft. All hoisting was done with a 12- by 16-in. slide-valve, double-reel, hoist. The hoist was being worked to its capacity and was unsuitable for hoisting from greater depths. As the work of opening a new level was about to be started, it became necessary to remodel the then-existing equipment or install a new hoist. The recent advent of electricity from Spokane had made available a cheaper power than steam. By a series of tests conducted throughout the Cæaur d'A1ene district, it was found that it cost $109 per year to generate a horse-power with steam. Electric power was to be had for $50 a horse-power per year. It was decided to substitute for the engines a motor-drive, of sufficient capacity to operate from the 900-ft. level, and ultimately install an entirely new hoist. After disconnecting the engines, installing a new shaft, and making a few minor changes, a 300-h-p., 2,300-volt, 514-rev. per min., variable-speed motor of the induction type was geared to the reel-shaft. The reels were supplied with 3/8- by 4-in. flat rope, and the duty of the hoist was about as follows: Cage, 1,700; ore, 2,600; car, 1,400; rope, 2,250; total, 7,950 pounds. The Bristol ammeter chart, Fig. 1, shows the combined current-consumption of the hoist- and mine-motors. The large intermittent load is clearly shown; this produced harmful fluctuations in the voltage of the long, lightly-loaded, 60,000-volt transmission-line from Spokane to the Cæmur d'A1enes. The power company received no compensation for the increased cost of producing power for this intermittent or fluctuating load. In order to protect its system from similar excessive

Jan 1, 1913

By J. J. Reed

The mines of southeast Missouri's Lead Belt have been in operation since 1864, almost 100 years. During this period about 10 pct of the total ore available has been left in place as pillars, and this now represents the best ore reserve left to the older mines. St. Joseph Lead Co. has been investigating various plans of pillar recovery for several years. The example to be described is only one possible approach under a specific set of conditions. Conditions vary greatly in the different areas within the Lead Belt, and the same approach would be entirely inadequate in certain other areas, but there are important sections where this system is clearly applicable. Horizon mining is practiced in the Lead Belt, and stopes may vary from 10 ft to well over 100 ft high. Fig. 1 is a plan view of 6100 stope, the area to be discussed. For these mines this is a small stope, only 10 to 12 ft high. Before any plans were drawn up for pillar recovery, three independent estimates of the pillar grades were made by the mine superintendent, the mine captain, and the mine geologist. After these results were averaged, pillars indicated to be of economic grade were marked for removal as shown. At this stage several alternatives were considered: 1) retreat with caving, 2) concrete replacement pillars, and 3) systematic bolting and retreat. A retreating system with caving was not chosen because the roof was known to be too bad even to permit loading a blasted pillar before caving would begin. Concrete replacement pillars would have been too costly and would have required a large crew, bulky materials, and unwieldy equipment. Systematic bolting was chosen as being most acceptable for the following reasons: 1) Limited area and spans were involved. 2) Only minor modifications to the jumbo would be required for bolting. 3) Only a two-man bolting crew would be needed. 4) Only compact bolting materials would be required. 5) The bolting plan could be modified to allow

Jan 1, 1960

By Lawrence Veiller, D. Eppelsheimer

D. Eppelsheimer, * Middletown, Ohio.—The housing of employees has so many and so varied aspects that in order to reach even an approximately correct solution it is necessary to have in mind a few fundamental principles; but it is not possible as yet to write these housing principles in the clear and correct form that is possible with many of our natural laws. Manifestly, the problem depends first on the kind of people it is necessary to house. What is suitable for the Southern unattached negro is not suitable for the married skilled American. The influx of colored labor has affected quite a number of what were satisfactorily housed communities. The second important factor is the relative proportion of the number of employees to the total employable population of the community in which the industry is located. The employer of a hundred men in a large city has little responsibility in the matter of housing his employees. If he employs 75 per cent. of the employable population in a community of 27,000, as is the case of the company with which the writer is connected, it means a large responsibility. In the establishment of an entirely new plant in a more or less isolated place, the responsibility becomes greater. As engineers, we design and write the specifications for the machinery to accomplish a definite purpose, and proceed to house it, provide the necessary buildings with their accessories in the way of cranes, or heating systems, or sprinkling systems, as the case may be. There is no reason why the operating force should not be built up in very much the same way: design the organization, write its specifications so that the employment department can secure the proper men, and then house that organization with just as much thought and care as is given the plant. In the plant, the various machines will work along certain definite lines and accomplish certain results; but even if we start with the proper organization it takes considerable time to get that organization working together. One of the most important elements to this end is the proper housing of the organization. A man usually spends more time at home than at work. Proper surroundings and a comfortable, convenient house of good appearance exercise an influence that cannot be denied, and an employee situated in such surroundings is far more inclined to follow the policies of his employer and take an active part in furthering them than one dissatisfied with his home and surroundings, which feeling

Jan 1, 1919

By Hans E. Gustafsson

INTRODUCTION The Kiirunavaara iron ore mine is situated in northern Sweden about 150 km north of the Arctic Circle. The ore body has a sheetlike shape, stretches about 4000 m N-S dipping 60°E and has an average width of 85 m. The ore body is known to a depth of more than 1500 m. Mining at present has reached a depth of about 500 m. The mineral is a magnetite containing 66-68% Fe. The ore body was originally mined as an open pit from 1900-1957. From then on the mining method has been sublevel caving. Production for the last few years has been 20-25 million tons /year. Sublevel caving is a mining method with many merits. One of the most valuable is the ability of using a high degree of mechanization. Today, 25 years after sublevel caving was introduced at Kiirunavaara, the advantages of the method have been more or less exhausted, and the disadvantages are more obvious as the rock pressure increases with depth. One of the disadvantages is the high degree of waste rock in the hoisted ore. Today the waste rock content is about 25% by weight of which 20% comes from the caved rock. Second, we are calculating a relatively high loss of ore (20%). Third, selectivity is unsatisfactory when mining different grades of ore. Field testing sublevel shrinkage caving (MSTM) is primarily aimed at lowering the content of waste rock compared to sublevel caving. ECONOMIC TARGET A simple calculation shows that if the waste rock content can be lowered from 25 to 15% the operational costs of mining will be lowered by about 40 million SEK/year (US $9 million) at a production level of 20 million tons/ year. A 15% waste content is the target of the field test. In the long range a decrease in waste rock dilution will mean lower investment costs for deeper levels. DESCRIPTION OF THE MSTM MINING METHOD One reason for decision to carry out the field test was that with MSTM the development drifts from sublevel caving could be utilized and thus the project could start without delay. The only additional development work needed was the loading level. Fig. 2 shows a profile through the MSTM area 66-68% Fe. and Fig. 3 shows the loading level.

Jan 1, 1981

By William Victor Vietti

West Texas and New Mexico have been overshadowed by the dcvelopment in East Texas to such an extent that the area has been placed on a settled production basis by most of the operators. Considerable develop-mCnt work on both proven and unproven acreage remains to be carried 011, but the incentive, a ready and profitable market, has been lacking. The main characteristics of the fields in this area are so well known that they are not described again in this paper, which thus resolves itself into a statistical review of the more important production features of the area. Proration has been in effect during the year and has been rigorously applied with the full cooperation of all producers. Proration in West Texas and New Mexico is based in the more productive fields on a potential and acreage distribution of the allowance to the individual wells or acreage units. Potentials are determined generally by a short production test of from 1 to 4 hr.; and the hourly rate is multiplied by 24 to obtain the 24-hr. production or rated potential of the separate wells. The potential values thus set up have been questioned by many production men who are not willing to concede that the instantaneous (hourly) capacity of a well to produce is its potential capacity for a day with all other wells in the pool producing at their capacity. However, the potential of a well determined as above remains its chief rating as a measure of the permeability in place and as an indication of the possible reserve feeding that well. The acreage factor has made it unnecessary to overdevelop properties in order to obtain an allowance proportionate to neighbors who are willing to drill an excessive number of wells on a piece of acreage in the hopes of a quick drainage and a corresponding profit. Proration has resulted in an orderly development of many of the pools in this area on the base as outlined above, resulting in more reasonable spacing of wells and the more even withdrawal of oil and the ensuing expectation of high recoveries. Big Lake.—Production from the shallow or 3000-ft. pay at Big Lake totaled a little more than 3,000,000 bbl. during the year, and we may expect a smaller recovery for 1933. The deep or Ordovician production

Jan 1, 1933

By O. E. Kiessling

THE present system of competitive exploitation of oil pools results in losses, both of petroleum and of profits. Under a competitive system the owner produces or withholds his product according to the price, which reflects the demand, but in the pe-troleum industry the producer does not have complete control over the expansion and contraction of his out-put. Under a series of court decisions, reviewed in detail in the paper, petroleum is not covered by- the general theory of English common law that the owner of land owns everything from the center of the earth to the sky within the areal limits of his property, but is considered to be his only when he has reduced it. to possession, which he can only do by taking it out of the ground. If A can obtain possession of the petro-leum which is beneath the property of B without tres-passing on B's property he commits no legal wrong and B has no defense except to get it into his (surface) possession before A takes it. No one would expect an. owner under such a system to forego the possibility of securing some oil from his property in order to in-crease the ultimate production of the pool. The pe-troleum industry. should offer a constructive program, that will eliminate losses and protect the interests of individuals as far as possible. If improved methods of oil recovery can be applied the quantity of petroleum recovered might be double or even treble the amount recovered by ordinary procedure. But increased recovery is not the only benefit from pool development. In brief, the following advantages can be claimed for unit operation: 1. Saving in development and operating costs. 2. Less danger of damage to the fields by defective wells. 3. Development is better gaged to fit market demand and to effect the most efficient recovery of oil. 4. More oil, gas, and gasoline can be marketed. 5. By regulating pressures, recovery .of oil and gas will be greater and the wells will flow longer. Reagan County (Big Lake), Rainbow Bend and Cabin Creek are examples of longer life of pools thus obtained.

Jan 11, 1927

By Rudolf Kudlich

The problem of eliminating the hazards of hoisting in mines has been with us since the industry passed its earliest stages, when coal and ore could be won from surface working and tunnels. At first, safety devices were introduced as means of decreasing the amount of labor necessary to produce the mineral, or to increase the amount that could be obtained from a certain opening. For example, crude ladders replaced winding footpaths or steps cut into the walls of the pit or shaft, decreasing the distance it was necessary to carry the product to the surface and eliminating, to some extent, the hazard introduced by the precarious footing afforded by such paths and steps. Latcr, instead of being carried from the pit on the backs of men, the product was hoisted in buckets or baskets on a rope passing over a pulley or around a windlass. Thus the capacity of the pit was considerably increased, and the hazard due to making many trips up and down the shaft was eliminated. From such beginnings accident prevention in mine hoisting advanced with the importance of the industry, until at present hoisting compares favorably with other branches of the mining industry with reference to safe practices. As in the other branches, this progress has been accomplished along two general lines—by legislation, rules, and education, and by the installation of safety devices. Though due credit must be given the former, it is not so satisfactory as the latter. Legislation, to be effective, requires a policing and inspection system to guarantee enforcement, such as we cannot hope to inaugurate. Rules may be satisfactory so long as the employer controls the labor market, and dismissal or some other form of discipline is an effective means of insuring obedience to the rules; but where labor demand is in excess of the supply, or where labor organizations are in control, such measures are not effective. An educational campaign will draw attention to hazards and may awaken a desire to avoid accidents by exercising the proper care. It is necessary, therefore, to place our reliance mainly on mechanical devices to prevent accidents, and to depend as little as possible on laws,

Jan 1, 1923

By L. A. Willey, William L. Fink

TWO of the aluminum-alloy systems previously studied—the aluminum-titanium and the aluminum-chromium—exhibit a peritectic reaction at the extreme aluminum end of the diagram. Preliminary work indicated that the aluminum-zirconium and certain other aluminum systems were similar in this respect. The present paper, the twentieth of a series from the Aluminum Research Laboratories, reports the results of a recent investigation of equilibrium relations in aluminum-zirconium alloys of high purity, which confirm the preliminary observations. Previous Investigations There has been only one investigation of the aluminum end of the aluminum-zirconium system. Sykesl prepared and studied alloys containing 0 to 70 per cent Zr. The lowering of the freezing point of aluminum by the addition of zirconium was found to be very little, if any (less than 2" C.). He placed the solid solubility of zirconium in aluminum at room temperature between 0.57 and 0.97 per cent. A few other investigators have attempted to determine the composition of the intermetallic compounds occurring in this system. Honigschmid2 obtained the compound ZrAla as a by-product during the preparation of ZrSi2. He made no attempt to prepare other aluminum-zirconium compounds. Weiss and Newmann3 prepared an alloy by heating aluminum with a double fluoride of potassium and zirconium. When this alloy was treated consecutively with caustic soda and hydrochloric acid, there was a residue, which contained approximately 72 per cent Zr and 28 per cent A1 (Zr3AI4). Marden and Rich4 prepared an alloy in the same way, treated it with caustic soda, and obtained a residue of silver-white crystals, which contained 70 per cent Zr and 30 per cent A1 (Zr3A14). Alloys Materials Used.—Electrolytically refined aluminum was employed for thc preparation of all alloys used in this investigation. The chemical

Jan 1, 1939

By Thomas Fraser, Robert MacLachlan

The dry cleaning of coal is a relatively new art and, as might have been expected, a number of unforeseen problems have been brought to light in the few years that dry methods of treatment have been in commercial use. The pneumatic concentrators that were first adapted to the cleaning of coal had already been developed to a fair degree of efficiency, although at low ratings, in the field of ore dressing. The concentrating machines, therefore, were in a relatively more perfected state than the general technology of dry cleaning and, for this reason, the major difficulties encountered in the early plants were in the accessory operations involved in the servicing of the cleaners rather than in the functioning of the cleaners themselves. The crudities of a new technology were further aggravated, in some cases, by meagerness of appropriations which precluded even the provision of adequate storage bins and such other facilities as had been long recognized as indispensable to the proper functioning of older types of cleaning plants. The practice of dry cleaning is now sufficiently established so that we may examine critically auxiliary equipment and operations. The cleaning processes have been so simplified, with respect to presizing of the raw coal required and the quantity of air circulated, that stinting of expenditures for auxiliary equipment is not necessary to keep the per ton cost of installation in line with complete and well designed plants of other types. Furthermore, sufficient operating experience has been accumulated to ascertain the conditions most conducive to effective operation of dry-cleaning machines; at least the essentials of a definite technology of dry cleaning has been established. Early Operating Problems The problems that have occupied the builders and operators of dry-cleaning plants from the beginning have been relatively few, but difficult of solution. The principal difficulties have been: 1. The proper sizing of the raw coal to suit the cleaning process. 2. The handling of raw coal when it is delivered wet from the mine. 3. Dust collecting. 4. The maintenance of uniformity in cleaning performance.

Jan 1, 1931

By G. B. Gould

THE softening temperature of coal ash, as determined in the labora-tory, has been used for years as an indication of the tendency of coal to form clinker and slag. It has not, however, provided an index of unfail-ing and complete reliability for forecasting the relative performance of different coals, even in the same plant and under the same conditions of operation. A large amount of investigation has been done in attempts to account for this, but practically all of this has been in the direction of studying the chemical constitution of coal ash. Much has been learned, but without much progress toward a better practical application of knowledge to the selection of coal. There has always seemed to be an important factor that eluded discovery. It has long been recognized that the ash-softening temperature as determined in the laboratory had one weakness, in that it represented the temperature at which a thorough mixture of the whole ash of the coal would melt, the mixing having taken place before the heat was applied. This does not, of course, simulate what takes place in practice. With certain exceptions, which will be noted later, almost all of the investiga-tions that have been made, especially the chemical studies of coal ash, have likewise dealt with a mixture of the whole ash in the coal. The present investigation differs from these fundamentally in its approach to the problem. It started from the observation that some clinkering and slagging obviously takes place in a boiler furnace at tem-peratures below the laboratory-determined ash-softening temperature of the coal. Knowing that coal as it is shipped to market is a hetero-geneous mixture of diverse mineral substances, each of which may act independently of the others in the initial stages of clinker and slag formation, it seemed logical to investigate separately the softening tem-perature of the ash in physically separable portions of the coal, and to determine the relative quantities of ash contributed by each portion.

Jan 1, 1940

By L. D. Jaffe, John H. Hollomon

THE hardenability concept has become widely used during the last few years for the choice and substitution of steels. Before the work of Grossmann,1 the systems for predicting hardenability from chemical composition could be used only over a narrow range of composition. Grossmann introduced a comprehensive system, which has been effective in calculating the hardenability of most types of moderate or low-alloy steels. However, occasions .often arise that require the calculation of the hardenability of high-alloy steels from their chemical compositions. Experimental determinations of the hardenabilities of such steels indicate that the Grossmann system predicts much greater hardenabilities than are realized. The fact that cases do arise in which the Grossmann method does not, apply indicates that the fundamental hypothesis of the system may not be generally applicable. It seems advisable to re-examine not only Grossmann's system but also the concept of hardenability itself. HARDENABILITY If steel parts are to possess a martensitic structure after quenching, they must first be austenitized and then cooled through the pearlite and bainite transformation ranges sufficiently rapidly to avoid the formation of pearlite, bainite, and proeutectoid products.* If, on cooling, these transformations are avoided, the resulting structure can consist only of martensite (and retained austenite). The hardenability of a steel is measured in terms of the severity of the cooling conditions necessary to avoid the pearlite and bainite transformations. The less rapid is the cooling necessary to prevent the formation of bainite and pearlite, the higher is the hardenability. The pearlite and bainite reactions appear to be differently affected by the alloying elements. Not only is this indicated by the published isothermal transformation data, but recent work by Zener2 affords a rational interpretation of the differing effects of the alloying elements. Manganese,3 for example, appears to decrease the rates of the pearlite and bainite transformations by equal percentages, while molybdenum4,5 is approximately 10,000 times more effective in retarding the pearlite than in retarding the bainite transformation, on the basis of isothermal measurements. In some steels, the formation of bainite restricts the formation of martensite while

Jan 1, 1946

By P. W. Bakarian

PREVIOUS determinations1,2,3 of the texture of magnesium and its alloys have shown only slight variations in the principal features of the structure. This investigation presents pole figures for magnesium and two of its alloys, in which differences of some magnitude will be shown. Schmid and Wassermann have considered the texture of magnesium in analogy with that of zinc-also a hexagonal lattice. Whereas the zinc texture is said to be derived primarily through basal slip and secondarily through {102}† twinning, the {102} twinning is considered impossible at the later stages of the rolling in magnesium because of its smaller axial ratio. This state of affairs appears reasonable for pure magnesium, but for alloy textures the situation is more complex. A double orientation similar to that found in zinc has been reported by J. D. Hanawalt,4 and the addition of small amounts of calcium to magnesium and its alloys to produce a double texture was noted by J. C. McDonald.5 The pole figures of this investigation, using an improved X-ray technique, show these various textures. The dependence of directional properties of rolled sheet on modifications of texture is well recognized. Correlation of physical properties with existing texture should be even more significant if quantitative valuations are attached to the various areas on the pole figures. Such a quantitative technique is developed herein. EXPERIMENTAL METHOD Two alloys were used, besides high-purity magnesium. In each case, the metal was extruded to bars 32 in. thick and hot-rolled to a thickness of about 0.075 in. It had been established previously that such a reduction was more than sufficient to eliminate the extruded structure. The rolling proceeded in the same direction as that of the extrusion, without any cross rolling. The temperatures corresponded to normal commercial practice, averaging around 600°F. A unique method of preparing the sample was developed in this work. Instead of using a flat specimen, a stem of the metal was cut out of the rolled sheet in the desired direction (rolling direction) as shown in Fig. 2. From a sheet of 0.075 to 0.065-in. gauge, the stem was cut to a square cross section with a jeweler's saw, rounded with a file and polishing paper to a diameter of 0.060 in, and evenly etched in dilute hydrochloric acid to a diameter of 0.038 ± 0.001 in. In this way, a cylinder of the original sheet with its axis in the desired direction was produced. By using this type of specimen for the pin-point pictures, any variance in the absorption of the diffracted beam at the various angular settings of the specimen, was completely eliminated.*

Jan 1, 1941

By D. R. Walker, M. C. Shaw

The laws of Kick and Rittinger are explained as functions of particle size with metal cutting theory. Comminution is shown to be basically the same process as metal grinding. The machine shop type of grinding operation is used to study mineral crushing. Evidence indicates that plastic flow occurs in comminution. THE laws of comminution of Kick and Rittinger have been debated for many years. Certain data obtained from ball mill and drop tests are found to be in approximate agreement with Rittinger's law while other data would seem to support Kick's law. In all these tests the energy required to produce a wide variety of particle sizes has been studied. Surface area has also been measured with considerable difficulty, at first because it was thought that the energy associated with crushing was that required to create new surface, later because of precedent and because a more fundamental variable was unknown. Tests made with the machine shop type of grinding process show that normally brittle materials that are usually crushed can behave like the more ductile metals. Brittleness is then a relative prop- erty largely dependent on specimen size and stress state. The machine grinding operation offers a convenient means for studying the comminution of materials in which the important size variable retains its identity. The energy required to grind a certain volume of material is shown to be strongly dependent on size. Kick's law is found to hold very well for particles below 1 micron in size, while Rittinger's law holds approximately in the comminution of larger particles. While a physical origin of Kick's law is established in terms of the theoretical strength of materials having a perfect lattice structure, there is found to be no physical basis for Rittinger's law. Because of its industrial importance, comminution has commanded considerable technical attention and has been the subject of continuous study for nearly a century. A number of empirical rules have been proposed to make it possible for grinding energies to be predicted. Of these so-called laws of comminution those bearing the names of Kick and Rittinger have been most widely applied and debated.

Jan 1, 1955

By Campbell Osborn

From the viewpoint of practical economic engineering the main value in studies of demand and supply lies in the information they give concerning the next movement of price. The title of this discussion is too comprehensive for detailed analysis and it will, therefore, be narrowed to the question of price measurement. The oil operator is interested primarily in net profits. Prices, costs and production determine them. Production is here used in its broadest sense. It includes refining and marketing. It is an operating problem. Prices and costs are economic considerations. Though costs are an important element of prices and profits, the subject is too large to be treated in a brief paper of this sort. In the long run, costs govern prices, but for the purpose of gaging prices in the immediate future the relationship of current demand and supply are more significant. Operating, expansion, retrenchment, sales and storage policies of oil companies are largely influenced by the feeling of executives concerning this relationship. The stockholders of companies whose executives are wrong may suffer. Investors who err in their judgment may likewise lose. On the other hand, oil companies and investors who appraise these factors correctly and move accordingly will profit. It is an important subject worthy of careful consideration. The author has been asked to discuss the subject for 1928. From the beginning of the year until the first of June, as illustrated by Fig. 1, over-supply prevailed in the face of restricted production, but from June to September, with record consumption, demand slightly exceeded supply and oil came out of storage in the United States as a whole. One of the main problems of the oil man is to decide whether this condition will continue and what the next movement of prices will be. Before he can do so he must have an understanding of the underlying conditions and of the facts that led to the present situation. With these facts in mind he is in a position to measure the effect of the present relationship of demand and supply on price and is afforded a perspective that may enable him to look ahead for a short period of time. The practical

Jan 1, 1929

By E. L. Bruce

GOLD occurs ill many mineral deposits in the rocks of the Canadian Shield. It is present in the ores of many base metals and a considerable quantity is recovered as a by-product from the production of copper at Noranda, of nickel and copper at Sudbury and of copper and zinc at Flinflon. But the greater part of the gold production of Canada is from deposits in which gold is the only metal of value. No gold is obtained from placer deposits within the borders of the Canadian Shield. A brief review of the geological relations of some of the gold deposits of the Canadian Shield will be presented in an attempt to explain certain associations. Only those which are being worked for their gold content will be considered and descriptions will be confined to representative types of deposits, chiefly those of major importance; a few others, differing in certain features from those of the older and larger mines, will be included in order to illustrate the general conditions in which gold occurs in these ancient rocks. Brief summaries will be given of the geological relations of the Beattie and Siscoe mines of northern Quebec, of the mines of the Porcupine and Kirkland Lake areas of northeastern Ontario and of the Howey, Central Patricia and Little Long Lac mines of northwestern Ontario. Genetic relations to igneous rocks of granitic composition, outcropping in the vicinity, have been assumed for many of these deposits. Undoubtedly the ore minerals have been derived from igneous sources and, for some occurrences, there is evidence suggestive of genetic relationship between the ore bodies and neighbouring intrusive rocks. During the past few years, however, many investigators have expressed doubt of the genetic relationship of certain ore bodies to igneous masses near which they occur. As will be seen from references in the following descriptions the importance of the structural conditions in localizing deposition has been realized. This is pointed out for Canadian pre-Cambrian gold deposits by E. T. Dougherty, who also refers to the

Jan 1, 1937

By William L. Fink, L. A. Willey

TWO of the aluminum-alloy systems previously studied—the aluminum-titanium and the aluminum-chromium—exhibit a peritectic reaction at the extreme aluminum end of the diagram. Preliminary work indicated that the aluminum-zirconium and certain other aluminum systems were similar in this respect. The present paper, the twentieth of a series from the Aluminum Research Laboratories, reports the results of a recent investigation of equilibrium relations in aluminum-zirconium alloys of high purity, which confirm the preliminary observations. Previous Investigations There has been only one investigation of the aluminum end of the aluminum-zirconium system. Sykesl prepared and studied alloys containing 0 to 70 per cent Zr. The lowering of the freezing point of aluminum by the addition of zirconium was found to be very little, if any (less than 2" C.). He placed the solid solubility of zirconium in aluminum at room temperature between 0.57 and 0.97 per cent. A few other investigators have attempted to determine the composition of the intermetallic compounds occurring in this system. Honigschmid2 obtained the compound ZrAla as a by-product during the preparation of ZrSi2. He made no attempt to prepare other aluminum-zirconium compounds. Weiss and Newmann3 prepared an alloy by heating aluminum with a double fluoride of potassium and zirconium. When this alloy was treated consecutively with caustic soda and hydrochloric acid, there was a residue, which contained approximately 72 per cent Zr and 28 per cent A1 (Zr3AI4). Marden and Rich4 prepared an alloy in the same way, treated it with caustic soda, and obtained a residue of silver-white crystals, which contained 70 per cent Zr and 30 per cent A1 (Zr3A14). Alloys Materials Used.—Electrolytically refined aluminum was employed for thc preparation of all alloys used in this investigation. The chemical

Jan 1, 1939

By W. B. Vietz, C. W. Hill, T. P. Thomas

FLUXES, in general, may be classified according to their use as soldering, foundry or casting, and metallurgical and the chemistry of their action follows quite closely this division. The term foundry or casting fluxes, as used here, refers to the substances added to molten metals, preparatory to casting into molds or ingots, with the object of removing small amounts of impurities that have been introduced in handling or melting the metal, which was placed in a fair state of purity by the previous refining or metallurgical processes. The sources of these impurities are the oxide coating on the surface of the ingots, material extracted or mechanically removed from the crucible or furnace wall, and those formed by the reaction of the molten metal with the heating gases or furnace atmosphere. As commonly used, the term fluxes is applied to such materials as ammonium chloride, zinc chloride, salt, borax, and boric oxide. A second class of materials, usually called deoxidizers, includes substances such as metallic phosphides, sub-oxides, carbides, and bo-rides, that reduce the metallic oxides present in the metal. A third class includes various compounds that arc molten and non-volatile at the temperature of the molten metal and are used primarily to protect the surface of the metal from the action of the furnace or exterior atmosphere; to this class belong such mixtures as lime and fluorspar, lime and soda ash, various minerals, etc. In some cases these protective layers may act in a manner similar to the metallurgical fluxes and dissolve or unite with the oxide impurities of the metal, but as generally employed this latter action is negligible since there is little opportunity for the coverings to come into contact with more than the surface of the metal, and hence they arc without action on the body of the molten mass. The use of fluxes is the result of factory experience and tradition, but an extensive study has not been made of the chemical and physical actions that occur or the effects of these actions on the properties of the metal. It would seem necessary in any successful study of metal fluxes to determine not only what impurities are present in metals melted under

Jan 1, 1921

By Eugene McAuliffe

IT is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the "do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co. has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as "extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment can be brought about when employer and employee work together with due sincerity. In presenting our own experi-ence, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. Safety work in some form has been carried on in and about the mining properties of The Union Pacific Coal Co. since the first mine was opened at the now long-abandoned town of Carbon, Wyo., in 1868. On June 30, 1903, an explosion and subsequent mine fire occurred in mine No. 1 at Hanna, taking 169 lives, and a second explosion occurred in tile same mine on March 28, 1908, in which 59 additional lives were lost. Looking back with impartiality on the causes leading up to these two unfortunate disasters, we can only conclude that shooting from the solid, the absence of adequate ventilation, rock dusting, the use of water at the face to allay

Jan 1, 1938