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By Ott F. Heizer

The mines and the mill of the Nevada-Massachusetts Co. are on the east slope of the Eugene Mountains, in Pershing County, Nevada, 8 miles northwest of Mill City, a station on the Southern Pacific R.R. and on the Victory Highway. Fig. 1. Supplies and, concentrate are transported by truck over an automobile road of easy grade. The property is at an average elevation of 5500 ft. and climatic conditions are generally favorable for continuous operation throughout the year. The ore treated is supplied by two adjoining mines, the Stank and the Humboldt. Physical and mineral characteristics of the ores produced by these two mines are substantially similar, although variations occur in hardness and mineral distribution.' The economic mineral is scheelite (CaWO4), composed, when pure, of 80.6 per cent tungstic trioxide (WO3) and 19.4 per cent lime (CaO).

Jan 1, 1935

By Heber Cole

THE gypsum industry of Canada, like all others connected with the construction business, has felt the full effect of the depression during the past few years, and sales of its products have been greatly curtailed. The year 1934, however, saw a decided turn for the better and a gradual but steady improvement is noticeable in all its branches. In many ways the depression has been a blessing in disguise to the gypsum industry; during the years from 1926 to 1930, demand increased so rapidly that companies were forced to expand and often new apparatus and machinery were placed in operation regardless of expense, or plants already existing were taxed to their limit and forced to keep running with the minimum amount of repairs. The depression, therefore, has really given the industry what might be called a breathing spell, in which it has had time to take stock of its position, to reduce its costs of production, to devote more serious attention to the quality of its products, and to con-solidate its operations into a smooth working whole, which as conditions improve will enable it to meet the demands of the trade with more varied products of a quality hitherto unattained. Progress in the gypsum industry, however, has not been confined to the years of the depression, for some of the greatest advances occurred under the spur of increased demand for its products by the building trade. The purpose of this paper is to review briefly some of the out-standing trends in the development of the gypsum industry in Canada during the past 10 or 12 years.

Jan 1, 1935

By Mark Malamphy

DURING the latter part of the year 1932, the Servico Geologico e Mineralogico do Brasil ordered four magnetic field balances with tem-perature-compensated magnetic systems and a photographic recording apparatus for the registration of the diurnal variation. These instru-ments were delivered during the early part of the year 1933 and a short time later were taken to Santa Catherina for use in the field. Before the field work was begun, a series of experiments was carried out to determine the behavior of these new instruments under existing field conditions. The recording instruments were mounted in an under-ground chamber and their sensitivities checked by means of a Helmholtz coil. The field instruments were then mounted at fixed stations and readings were taken to determine the diurnal variation and compare it with the photographic records. The data obtained with the horizontal field balances were concordant but that obtained with the vertical component instruments showed a considerable divergence. This divergence was of such a magnitude that it was necessary to spend considerable time in determining its cause and finding a means of improving the functioning of the instruments. This paper presents the results of our observations on these systems and the conclusions at which we arrived; also the means we took to partly elimi-nate the difficulty until new systems could be ordered from Germany.

Jan 1, 1935

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1934 are available at Institute headquarters, unless otherwise noted They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS Copies of the TECHNICAL PUBLICATIONS have been mailed to those members of the Institute who are registered in the different classes A-Metal Mining, B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Insti¬tute of Metals Division; F-Coal Division; G-Petroleum Division; H-Nonmetallic Minerals; I-Mining Geology; J-Mineral Industry Education Division; K-Mining Administration; L-Geophysical Prospecting Other members may obtain copies by writing to the Secretary Copies of CONTRIBUTIONS may also be obtained from the Secretary's office Additional copies are sold at the rate of 1 cent per page, minimum charge, 25 cents Nonmembers may purchase the papers at the prices mentioned

Jan 1, 1935

By Russell Dayton

THE metallurgical polarization microscope has been utilized in several researches in the last few years, thus attaining a fair degree of prominence, but little has been written in a manner suitable to a metallurgist concern-ing the theory of this instrument. In this investigation the theory was carefully studied, and the results are presented here in a detailed manner, yet as simply as possible. The theory is discussed with particular reference to the three chief functions of the instrument: (1) determination of anisotropy; (2) effect of strain; and (3) identification of inclusions. Each of these is investigated experimentally, with especial attention to the mechanism of producing any effect. Where possible, the discussion is supplemented by photomicrographs. The instrument used had numerous defects as a polarization microscope; these and their remedies are discussed. In the microscopic study of transparent mineral sections (chal-cography) the use of polarized light has aided tremendously in the identification of a mineral. The determination of strain in transparent substances (photoelasticity) by the use of polarized light has lately become a commercial process, used in testing finished glass articles. The success of the use of polarized light with opaque materials has not been so great. The magnitude of the effects obtained is much less than that of the corresponding effects with transparent materials, and the mechanical difficulties are much greater. Konigsberger,(1)? in 1909, was the first to apply polarized light to the microscopic study of

Jan 1, 1935

Jan 1, 1935

Jan 1, 1935

By Anthony Anable, J. V. N. Dorr

When separate treatment of sand and slime by cyanidation was the rule rather than the exception, as now, and when gravity concentration, rather than flotation, was the accepted method of dressing copper, lead, zinc and other base ores, classification was a separate step in ore treatment. Today, however, the picture is much different. The trend toward all-slime treatment in cyanidation and flotation has made fine closed-circuit grinding essential, and the mechanical classifier is of equal importance with the mill in the preparation of an ore for its treatment. Actually, a mill and classifier are a unit, a variation in either affecting the desired results. In developing this thesis—the mutual interdependence of the rotary mill and the classifier in modern fine-grinding practice—it would be well to consider first the different types of classifiers and mills in use today, their scope and limitations and the factors governing their selection. From such a basis as this a logical approach may be made to modern closed-circuit fine grinding, the evolution of multiple-stage grinding practice, the relation of the classifier to the mill and, finally, the trend to higher and higher circulating sand loads in the mill-classifier circuit. Such data as are germane to the subject will be given to support the thesis advanced. Mechanical Classifiers Theory.—Stokes' law, applicable to the uniform slow motion of a rigid sphere in a viscous fluid of infinite extent, states that the velocity of a particle settling under the influence of gravity is a function of the square of its radius: _ 2 g(ds - de)?2 v =9 S Where V = velocity of particle in cm. per see. g8, acceleration due to gravity d8, density of particle de, density of fluid ? = radius of particle S = viscosity of fluid

Jan 1, 1935

By Ravitz, S. F

76-B Unpublished manuscript. Not available in printed form. An experimental and Theoretical investigation of Quantitative Microscopic Mineralogical Analysis. By S.F.Ravitz and H.A.Steane. Manuscript in Engineering Societies Library.

Jan 1, 1935

An Outline Classification of Mining Systems for Ore and Coal. See COAL Progress at the Homestake Mine. By Guy N. BJORGE. (Min. & Met., June, 247. 4400 words.) Homestake's mining methods today are controlled to a con¬siderable extent by that which has been done in the past. The two main operating shafts were begun m 1878 and 1896 respectively, so that the location of shafts, loca¬tions of all the drifts on the upper levels, and a great deal of stoping was done before any of those now connected with the mine had anything to do with it In this paper is described the general plan of development. A table shows percentage of total production mined by the different methods in recent years. Average daily produc¬tion for several years now has been about 3850 tons milled. With the present schedule of 6-day operation of the mine, that means about 4450 tons a day mined This ore is treated at three plants, with respective capacities of 2000, 1200 and 600 tons The principal novelty in milling is at the largest mill where the stamps are used as crushers only, and where in the last two years a notable increase has occurred in the size of screens used A unit has been added to cyanide plant No 3 The construc¬tion of a new shaft is described, as is also the hoist building The company operates its own lumber and timber department It has a well equipped hospital Housing at Lead is an individual matter. Rejuvenating the Golden Chariot Property in Idaho. By R. S. MCCLELLAN (Min. & Met, November, 443. 2300 words) An effort to rejuvenate the Golden Chariot group of properties near Silver City is now being carried on by the John Hays

Jan 1, 1935

By R. K. Hopkins

Fox a great many years fusion welding has been used in and around petroleum refineries, but it is only within six or seven years that the more important pressure vessels have been constructed by this process, because before that time the properties of fusion welds would not withstand such rigorous service. Since the adoption of fusion welding for the construction of this equipment, the refiner has required pressure vessels suitable for operation over a very wide range of conditions. On the one hand, vessels must operate at extremely high temperatures, in the range of 950° to 1000° F., and on the other vessels must be suitable for operation at sub-zero temperatures down as low as -75° F. Also, vessels are required suitable for operation at pressures upwards of 1000 lb. per sq. in., and as low as a 29-in. vacuum. In addition, vessels are required to withstand the attack of very corrosive mediums. It has been a rather difficult task for the fabricator to meet all of these requirements, but as a result of the extensive research carried on by steel manufacturers and several fabricators of class I vessels, practically all of these demands have been met. In order to meet the refiners' requirements for this wide range of conditions, the fabricator has worked closely with the metallurgist. This has enabled him to choose the proper base metal for each service condition, but it has been the fabricator's problem to develop a welding rod and welding technique, as well as a heat-treatment, that would produce in the welded vessel characteristics in and around the weld comparable to those in the base metal. Where corrosion is not a serious problem, and where the operating temperatures are not too high, ordinary carbon steel has served very well. But when corrosion is serious, and/or when the temperatures are either very high or very low, it is necessary to use some form of alloy steel to give satisfactory service.

Jan 1, 1935

By A. L. Field

This general subject has been so thoroughly discussed by Dr. Herty and his associates, especially with regard to the degree of oxidation of the metal at the time that the silicon pig or spiegel is added, that I am not going to spend much time on that today. I should like to propound a question, which is based on my own observations made some years ago while with a large alloy-steel company which had two open-hearth furnace plants. It is true that one of these plants was not engaged particularly in making alloy steels, but there were certain relations between slag and metal composition which appeared to me to be entirely different in the two plants. I have an explanation for it that is more or less incomplete, but possibly Dr. Herty or Mr. Reinartz or some of the others may be able to complete it. Suppose we take our three layers; the metal on the bottom, on top of that the slag, and on top of the slag, the gas. We cannot overlook the gaseous phase. Regardless of the effect of the iron oxide in the slag on the rate of carbon elimination—and that, of course, is rather important in alloy practice since it is not desirable to have the carbon dropping too rapidly at the time the deoxidizing is had in the furnace—it will probably be admitted that it depends on the iron oxide in the metal for a given carbon oxide. I have seen cases where with approximately identical metal and slag compositions one furnace would work twice as rapidly as another in removing carbon. Of course, there is some explanation of this in what others have already said, that the question of the exact lime and silica content of the slag determines the activity and viscosity of the slag; but I am convinced, without having reviewed the actual records since I was asked to make this talk, because they were not available at the time, that the slags in these two furnaces were not materially different. Putting it another way, one furnace would have

Jan 1, 1935

By G. Hileman

During the year 1934 there were no new or extraordinary developments in the proven fields. With few exceptions all companies operating in these fields continued intensive exploitation programs on their old properties in an attempt to maintain the normal production of former years. In one or two instances these exploitation activities have had such marked success that the total production for 1934 slightly surpassed that of 1933. The most striking increase in production is that shown by the Kilometer 27 pool of the Comodoro Rivadavia field. However, this increase cannot be attributed to intensive drilling, since it is the result of a more uniform daily withdrawal distributed among all the productive wells. The Province of Salta also showed another increase, so that, judging from the statistics of the past three years and in view of proposed exploration projects, the future may reveal some interesting developments in this province. One of the most interesting occurrences in Salta is the discovery, though not yet considered commercial, made at Macueta, near the boundary line between the Argentine and Bolivia. This exploration well was drilled by the Standard Oil Co. of New Jersey and is the northernmost exploratory well in the republic. The oil from this well is of the same type and commercial value as that produced in the San Pedro and Lomitas fields. The producing horizon is also the same as that in the other Salta fields; that is, the Paleozoic Permo-Carboniferous.

Jan 1, 1935

By G. S. Hume

The production of petroleum in Canada is relatively small in proportion to the amount of oil consumed. Production figures are given in Tables 1 and 2, which show that the production in Alberta for 1934 was more than for the whole of Canada in 1933. The production of natural gas for Canada is shown in Table 3, In Turner Valley, the largest producing gas and oil field in Alberta, seven naphtha wells from the Paleozoic limestone and one crude oil well from Lower Cretaceous strata were completed during the year. Six-

Jan 1, 1935

By L. C. Uren, J. Domerco

That the diameter of a well through the oil-producing formation has an important influence on its rate of production is a principle accepted by many petroleum technologists. Knowledge of this principle extends back at least to the time when Slichter and King1 confirmed it in a study of the dynamics of flow of water through porous strata into wells. More recently, the senior author2 and his associates3 have produced qualitative experimental data confirming the principle as applied to drainage of expanding oil and gas mixtures, and suggesting that wells of large diameter, or wells having cavities about them within the reservoir rock, enjoy a material advantage in competition with wells of ordinary diameter. Apparently, however, no one has produced experimental data designed to indicate quantitatively the advantages that wells of large diameter possess in comparison with wells of normal diameter producing under comparable conditions. This paper reviews some preliminary experimental results of this kind, together with some conclusions and speculations based thereon, which further emphasize the importance of well diameter as a factor in determining the efficiency of oil recovery. Theoretical Aspects of Radial Flow of Fluids into Wells It is well understood that in a reservoir rock of uniform thickness and permeability oil and gas flow toward the wells along radial lines. The cross-section of the reservoir rock through which the fluids must move becomes ever smaller as the wall of the well is approached. The velocity of flow must therefore correspondingly increase, an effect that is accentuated by the rapid increase in volume of the fluid due to release

Jan 1, 1935

By G. R. M. Del Giudice, A. F. Taggart, Othon A. Ziehl

In a previous paper1 in which one of the authors collaborated, it was postulated that All dissolved reagents which, in flotation pulps, either by action on the to-be-floated or on the not-to-be-floated particles affect their floatability, junction by reason of chemical reactions of well recognized types between the reagent and the particle affected. This generalization, apparently, like many pioneer structures, had for certain observers a flimsy appearance, and these, judging its stability rather by the number than by the character of its foundation posts, have attempted variously to overthrow it, either by the frontal attack of general denial, or by the flanking movement involved in assuming that those cases in which the facts were unknown or unproved were, therefore, discordant. But as time has passed and further evidence on the question has accumulated, it has become apparent that the results of verifiable experiments add stone by stone to the substructure of the hypothesis, and that the super-tructure has lost nothing in weathering. The present paper constitutes an examination of the opposing positions in the light of the more recent evidence developed. It will clarify the discussion if, at this point, we state more fully the implications of the disputed hypothesis. In the first place, it is explicitly limited to reagents that are dissolved in the water of the flotation pulp. Next, it refers only to such of these dissolved reagents as act on the solid particles in the pulp to affect their floatability. This includes the collectors, activators, and certain depressors and gangue-control reagrnts, but not the pure frothers, and not, necessarily, conditioners whose function seems to be merely that of pH control, although in certain cases it has been demonstrated that such control has the effect of regulating the primary reaction of the collector, depressor, or the like. Finally, there is no limitation as to the nature of the chemical reaction postulated.

Jan 1, 1935

By M. N. Short

It is almost self-evident that the student of geology depends for his education in geology only in small measure upon his own observation. His chief sources of information are lectures and personal instruction from teachers, and the geological literature. Of these, the literature is by far the most important. The total geological knowledge available to the geologist of today is substantially that which is on the printed page, and no more than that. There are many geologists of outstanding rank who during the course of a busy and useful professional career have accumulated valuable geological knowledge. This, however, is never available to the profession, owing to the disinclination of these geologists to write or to the refusal of their employers to allow the results of their work to be published. With the passing of these geologists, their accumulated knowledge is irretrievably lost. In many mining districts the operating companies are not averse to the publication of geological information gathered by their engineering and geological staffs, but for various reasons this information is not published. However, when a public survey geologist goes into the district this information is placed at his disposal and eventually is published. But for the intervention of a disinterested public scientist, this information would have been buried in company files. In the last analysis, the teachers themselves depend largely upon the printed page for the knowledge they pass on to the student. Without geological literature, then, the instruction of geological students would be almost impossible. There is no .question that, as a whole, geologists who are on the public payroll have to their credit far more contributions to literature than have either teachers or professional geologists, whether the latter be independent or in the employ of private corporations. The very fact that geologists are upon the public payroll places them under obligation to make available to the public the results of their endeavors. They must either prepare these results for publication or they must furnish data or otherwise aid their colleagues to publish their results. The success or failure of a public geological survey depends entirely on the

Jan 1, 1935

By Francis M. Rich

BEFORE the world-wide depression, the primary purpose of most blast-furnace operators was to produce a maximum tonnage of pig iron per day for each furnace in blast. Some attention was paid to the conservation of labor and raw materials, but the idea was well established that low-cost pig iron was attainable only when each furnace was producing a high tonnage. After the depression had set in, the picture changed considerably. Each blast-furnace operator was forced to run his plant in a manner that best fitted the economical set-up of his company. A great deal of thought was expended on the different methods of operation, always with the idea of making each product in a way that would best serve his company financially. Because of this abnormal condition, the blast-furnace man was compelled to indulge in various practices of which many had been believed to be next to impossible up to that time. The ultimate purpose of these innovations was either one or a combination of the following: 1. To produce only enough pig iron for immediate consumption at a minimum cost. 2. To produce gas for boiler or mill use to supplant some higher priced fuel. 3: To consume the coke produced at the coke plant, which was often viewed as a byproduct. 4. To protect the cash position of the company. These conditions were met by diverse methods, some of which were: 1. Slow or decreased wind. In some instances the blast blown was held as low as 25 per cent of the normal volume. 2. Intermittent operation, in which the furnaces were shut down or "fanned" at frequent intervals.

Jan 1, 1935

By John Chipman

RECENT developments in iron alloys containing nitrogen have indi-cated that this element may exert a considerable influence on the proper-ties of the metal. This influence is not always in an undesirable direction and the indications are that nitrogen should be regarded as an alloying element, the amount of which should be subject to control, rather than as an inherently deleterious impurity. In controlling this element in liquid iron to the best advantage, it is necessary to have a reliable background of fundamental data pertaining to solubilities, rates of solution and chemical reactions of nitrogen in liquid iron. Obviously, the first step in such an investigation is the determination of the solubility of nitrogen in pure iron, and this has been the object of the experiments described in this paper. The solubility of nitrogen in solid iron has been measured by Jurich,1 Sieverts,2 Martin,3 and Iwasé4 and the agreement among the first three inspires confidence in their results. No accurate determinations of its solubility in liquid iron have been recorded though several investigators have obtained approximate results. Strauss5 was able to introduce 0.03 to 0.04 per cent nitrogen into steel by the action of either ammonia or nitrogen on the liquid metal. This was accomplished by Eilender and

Jan 1, 1935

By Paul D. Merica, W. A. Mudge

One of the most prominent features of our present-day industrial development is the ever-increasing demand put upon materials of construction. Engineering ingenuity, within the past 25 years, has been unusually active, and in some fields at least engineers frankly say that engineering design has progressed as far as the limitations imposed by the properties of the present materials of construction will permit. Consequently, they are today demanding improvement in their working materials and seeking new ones, through the aid of which the present limitations of design may be overcome. The activity of this search is evident in all fields, but it is particularly so in that of structural materials required to be resistant to corrosion. The corrosion resistance of metals and alloys is never absolute and all-inclusive; a particular alloy will withstand some corrosive conditions well and fail utterly under others. Furthermore, other properties, physical and mechanical, required in conjunction with corrosion resistance vary considerably for different commercial applications. One wants a soft, ductile sheet metal resistant to atmospheric corrosion; another, a high-strength alloy resistant to sulfuric acid. The last decade has witnessed active and definite progress in the development of high-strength, corrosion-resisting alloys. In June, 1924, a symposium by the American Society for Testing Materials, on Corrosion-resistant, Heat-resistant and Electrical-resistance Alloys, disclosed no less than 60 commercial alloys the properties of which were described as being suitable for industrial service where corrosion resistance was a feature. Today the number of these alloys has been doubled, at least. In addition, economy in design and construction through decreased weight has given considerable impetus to the improvement of alloys of which the mechanical propprties may be improved by heat-treatment.

Jan 1, 1935