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By Charles V. Seastone

The hydro-electric plant of the Peninsular Power Co. is located at what is commonly known as Lower Twin Falls on the Menominee River. This location is about 3I/2 miles north of the city of Iron Mountain, Mich. The principal points of delivery of electric energy from this plant are in the mining regions adjacent to Florence, Wis., and Iron River, Mich., and in the cities of Iron River and Iron Mountain. The hydro-electric plant at Twin Falls and the substation of the Iron Mountain Electric Light & Power Co, are connected by a 6,600-volt transmission line carried on steel towers and steel poles, the latter being used within the city limits. The plant at Twin Falls and the substation at Iron River, about 36 miles distant, are connected by a 66,000-volt, duplicate, three-phase transmission line, supported on steel towers. At Iron River, are located a 1,500-kw. auxiliary steam plant, and the substation, from which the current is distributed to the mines in this vicinity. A description of the auxiliary plant, main and customers' substations, and of the main and secondary transmission lines, follows later in this paper. General Layout The relative location of the dam, forebay, and power house will be understood by referring to Fig. 1. The dam is constructed on a ledge of solid rock which forms Lower Twin Falls. This rock ledge offers an excellent location in that the height of the dam, and therefore the amount of concrete, are thereby reduced, and also in that practically no pumping was required in unwatering the dam site. The maximum head provided by the dam is 44 ft., with an average working head of from 40 to 42 ft. The other structures, including the substructure of the power house,

Jan 1, 1915

By R. W. Raymond

It is impracticable to prepare for the present number of the Bi-Monthly Bulletin a detailed account of the memorable Joint Meeting of the Iron and Steel Institute and our Institute, held in London, the last week in July, and of the, innumerable festivities, entertainments and excursions which accompanied and followed it, in England, Scotland, Wales and Germany. This preliminary sketch, from which all " useful particulars "' have been carefully omitted, is published unofficially, as a convenient answer to the manifold inquiries of members who did not go, and who are now trying to alleviate their unavailing regret by indulging their curiosity. Perhaps they secretly hope to hear that they did not lose so very much, after all-that the affair was not all that could have been desired or dreamed; that there were serious drawbacks, shortcomings and disappointments; and that it is just as well to have stayed it home, and now to hear about it. Let them lay no such flattering unction to their souls. The month they have missed would have been the time of their lives. They will never, never know how good a time it was, or adequately repent of their folly, if they could have gone with us, and voluntarily did not go of course, those who would but could not, have our immeasurable pity, without blame. I shall present here no consecutive and minute story, but only a series of general paragraphs concerning different aspects and stages of our experience. THE WEATHER. The proverbial good fortune of the Institute attended its visiting members and guests at every stage of the late London meeting and the numerous excursions which accompanied or followed it. Even the process of crossing the Atlantic was made delightful by smooth seas, through which the great modern transatlantic liners made their way without disagreeable

Sep 1, 1906

By J. H. Schloen, C. W. Clark

Two papers have been written previously concerning operations at the Montreal East plant of Canadian Copper Refiners Limited. The first one,' written in 1932, described silver-refinery operations at the time for producing silver and gold bullion from tankhouse anode slimes; the second,2 published in 1933, consisted of a description of the entire plant. Since publication of these papers the refinery has become the world's largest producer of refined selenium. The first selenium was produced in August 1934. Tellurium production on a commercial scale followed in October 1935. This paper will deal with selenium and tellurium production and also with present operations in the silver refinery. Blister cakes from Hudson Bay Mining and Smelting Co., Flin Flon, Manitoba, and commercial anodes from Noranda Mines Limited, Noranda, Quebec, are refined at Montreal East. Both these bullions have unusually high gold, selenium and tellurium content. The average assay of raw slimes produced from domestic and Noranda anodes is about 40 per cent Cu, 3600 oz. per ton Ag, 800 oz. per ton Au, 22 per cent Se and 3.7 per cent Te. Early Silver-refinery Operations From the start of operations in 1931 until July 1934, the raw slimes were oxidize-roasted at 700" I?. in a Nichols-Herreshoff furnace, acid-leached with tankhouse discarded foul electrolyte (20 per cent H²SO), filtered and charged directly to the doré furnace for refining to doré meta1. This is the customary method for treating tankhouse anode slimes but was not suitable at the Montreal East plant because of the high selenium and tellurium content of our slimes. In the acid-leaching process about 50 per cent of the selenium and tellurium in the roasted slimes was dissolved in the electrolyte. These elements were recovered with the copper as a sludge in a small electrolytic

Jan 1, 1943

By C. W. Clark, J. H. Schloen

Two papers have been written previously concerning operations at the Montreal East plant of Canadian Copper Refiners Limited. The first one,' written in 1932, described silver-refinery operations at the time for producing silver and gold bullion from tankhouse anode slimes; the second,2 published in 1933, consisted of a description of the entire plant. Since publication of these papers the refinery has become the world's largest producer of refined selenium. The first selenium was produced in August 1934. Tellurium production on a commercial scale followed in October 1935. This paper will deal with selenium and tellurium production and also with present operations in the silver refinery. Blister cakes from Hudson Bay Mining and Smelting Co., Flin Flon, Manitoba, and commercial anodes from Noranda Mines Limited, Noranda, Quebec, are refined at Montreal East. Both these bullions have unusually high gold, selenium and tellurium content. The average assay of raw slimes produced from domestic and Noranda anodes is about 40 per cent Cu, 3600 oz. per ton Ag, 800 oz. per ton Au, 22 per cent Se and 3.7 per cent Te. Early Silver-refinery Operations From the start of operations in 1931 until July 1934, the raw slimes were oxidize-roasted at 700" I?. in a Nichols-Herreshoff furnace, acid-leached with tankhouse discarded foul electrolyte (20 per cent H²SO), filtered and charged directly to the doré furnace for refining to doré meta1. This is the customary method for treating tankhouse anode slimes but was not suitable at the Montreal East plant because of the high selenium and tellurium content of our slimes. In the acid-leaching process about 50 per cent of the selenium and tellurium in the roasted slimes was dissolved in the electrolyte. These elements were recovered with the copper as a sludge in a small electrolytic

Jan 1, 1943

By N. Christensen, B. Augland, T. H. Johansen

Samples of an Fe-Nb alloy were brought to equilibriurtr with hydrogen-methane mixtures in the temperature range from 950° to 1050°C, and subsequently analyzed on their carbon contents. The solubility pvoduct L = [%Nb] [%C] may be represented by the equation Approximate solubilities indirectly assessed through hardness measurements have been included from a previous report. These data are shown to be in a fair agreement with the present solubility measurements. IN an investigation based on hardness measurements by de Kazinczy, Ms, and pachleitnerl the molal heat of solution of NbC was estimated to 11.5 kcal per mole. This value was considered rather small, and an investigation using a similar technique was carried out. The results indicated a heat of solution about 35 kcal per mole.2 At this stage it was decided to determine the solubility under conditions of true equilibrium . During the course of this work a similar investigation was published by Smith. 3 His heat of solution, 41.6 kcal per mole, is not very different from the value resulting from the present work (42.5 kcal per mole). Our solubility product, on the other hand, is at considerable variance with that reported by Smith. Possible reasons for these differences are discussed below. Mori, Tokizane, and saheki 7 have studied the behavior of niobium in commercial steels, with special attention to the formation of niobium carbide, nitride, and sulfide. Assuming a carbide composition Nbco.87 based on X-ray diffraction and chemical analysis of residues extracted from Fe-Nb-C-S alloys, the molal heat of solution of niobium carbide was estimated to 35.2 kcal per mole. MATERIALS AND EQUIPMENT The chemical analysis of the materials is given in Table I. Electrolytic iron* was used in the preparation of

Jan 1, 1968

By Robert Ammon

The purpose of this paper is to present a brief sketch of the development of this hindered-settling classifier, but primarily to show the actual results obtained in practice with the classifier working on the Butte copper ores at the Boston & Montana Concentrator at Great Falls and the Washoe Concentrator at Anaconda. The writer has endeavored to be as brief as possible, giving only the essential figures showing the efficiency of the classifier and leaving considerable interesting information to be derived by the reader from the statistics given. The paper deals with the practical work of the classifier under the following heads: 1. Desliming 4.0-mm. primary feed, overflow from 0.07 to 0.0 mm. 2. Desliming 1.25-mm. secondary feed, overflow from 0.07 to 0.0 mm. 3. Desliming Huntington Mill discharge, overflow from 0.07 to 0.0 mm. 4. Classifying 2.5-mm. deslimed secondary feed, overflow from 1.00 to 0.07 mm. 5. Classifying 2.5-mm. deslimed primary feed, overflow from 0.75 to 0.07 mm. 6. Classifying 4.0-mm. deslimed primary feed, overflow from 0.75 to 0.07 mm. 7. Classifying middling-tailing product from roughing tables, overflow coarse tailing. 8. Classifying 2.5mm. trommel undersize, not deslimed, overflow from 0.75 to 0.0 mm. 9. Remarks on the inner feed cone. In the following pages all overflows are given in quartz dimensions; i. e., by a 0.75-mm. overflow is meant an overflow whose maximum particle is a 0.75-mm. quartz grain. By the term "slime" is meant all material which will pass through a 200-mesh screen whose average opening is 0.07 mm. The development of the classifier was commenced in the fall of 1910,

Jan 1, 1914

By J. R. Long, E. T. Hayes, R. S. Dean, F. S. Wartman

THE production of titanium in 15-1b. lots and with a purity sufficient to be consolidated into ductile metal, as described in a previous paper,1 has provided adequate material for a study of the : physical properties of titanium and a more thorough examination of its working qualities. Data on the physical properties reported in that paper were obtained on metal fabricated by a fixed procedure, standardized for the purpose of control of the reduction, and are representative only of material fabricated under those conditions. There are many possible variables in the working schedule, which will have significant effects on the properties of the finished material; and since the previous working methods were not necessarily the best, an investigation of the fabrication of titanium by other methods was undertaken. In this work the consolidation of the powder by pressing and sintering was conducted essentially as outlined in the report cited' and all efforts were centered on fabrication methods for those powders and the properties produced by them. Hardness, density, microstructure, and tensile properties were determined at various stages in the working and annealing; and resistivity measurements were made on a few bars and drawn wire. [ ] CONSOLIDATION OF THE POWDER The screen analysis of the available titanium powder is given in Table I. No attempt was made to alter the size distribution from that noted because this powder, although coarse by normal powder-metallurgy standards, produced acceptable compacts suitable for the present work. Because of their large specific surface, finer powders are more contaminated by oxygen and produce harder compacts, which are difficult to work. The powder as produced is soft, compresses in a normal fashion, and exhibits very little tendency to adhere to the die surfaces. Unlike aluminum and magnesium powders, it can be readily pressed without the use of die lubricants. When compacted at so tons per

Jan 1, 1946

By G. L. Oldright

THE development of the reverberatory furnace for smelting copper ores up to 1912 was described by E. P. Mathewson1 with details concerning the great changes in dimensions of the furnace. Hayward2 tabulated similar data, giving developments up to about 1924, in his revision of Hofman's Metallurgy of Copper. DEVELOPMENT OF PRESENT SMELTING PRACTICE Dimensions of Furnace Very great changes were made in the dimensions of the smelting hearths of the furnaces in the period from about 1800 to 1906, the length increasing from about 11 to 116 ft., and the width from 8 to 19 ft. During this time the tonnage smelted increased from about 9 to 250 tons per 24 hr., and the tons of charge smelted per ton of coal increased from 0.77 to 4.3. Dr. Mathewson3 noted no great difference in the "fuel ratio" (i. e., the amount of charge smelted per ton of coal) as the furnace at Anaconda was increased in length by stages from 85 to 116 ft. (The percentage of copper in the slag, however, was lowered from 0.42 to 0.36 per cent. The other components of the slag were not given.) Lump coal fired on grates was the fuel used during this period. The practice in operating the furnaces over such a length of time naturally varied considerably, and there were differences in composition and nature of the charge, yet it may be considered that the improvements made were due largely to increases in the size of the furnace used. Doubt-less some credit should be given to improvements in operating technique, like changes in the methods of firing the lump coal. However, the greater part of the advance was probably due to factors influencing the

Jan 1, 1928

By Arthur O. Gates

RittingeR's law of the energy expended in crushing is, as roughly stated by Profcssor Richards,' that the work of crushing is proportional to the reduction in diameter; or, as I have more fully expressed it: "The work done in crushing is proportional to the surface exposed by the operation; or, better expressed for this purpose, the work done on a given mass of rock is proportional to the reciprocal of the diameter of the final product—assuming that all the mass has been reduced to one exact sine, which is only theoretically possible."² Kick's law is stated by H. Stadler as follows :3 "The energy required for producing analogous changes of configuration of geometrically similar bodies of equal technological state varies as the volumes or weights of these bodies." In other words, the energy expended is proportional to the volume reduction, instead of the diameter reduction. That these two laws would give widely different results may be shown by a simple imaginary case. A ton of 16-in. cubes is broken to 1-in. cubes at the first operation, and these are broken to 1/16. cubes at a second operation. Since the first operation produces only one-sixteenth as much new surface as the second, the ratio of energy expended in the two operations would be by Rittinger's law as 1 to 16. By Kick's law, since the volume-reduction ratio is the same in both cases, the ratio of energy would be 1 to 1. This discrepancy is great enough to challenge a test by actual experiment, of which there has been, hitherto, but little compared with the amount of argument. The present paper is the record

Jan 1, 1916

By John C. Branner

No precise geographic limits can be given for the zinc- and lead-region of North Arkansas. In general terms it lies N. of the Boston mountains and W. of the St. Louis, Iron Mountain and Southern railway; but the prospecting and the development of the ore-deposits have not gone far enough to outline more than vaguely the areas over which workable deposits are to be expected. The tardiness of the development of the region is due in part to its topography, as a hilly and partly mountainous country, through which there have been no railways until recently. There is no longer any doubt, however, about the existence in that region of large bodies of zinc-ores. I. General Geology. The general geology of the region is, in the main, quite simple, but that of the ore-deposits is less so. The zinc-regions of North Arkansas lie about the southern flanks of the Ozark dome. The rocks are approximately horizontal, but have a gentle southward dip away from the axis of this dome. Figs. 1, 2 and 3 show the broad features of the to-. pography and geologic structure. South of the zinc-region, the sandstones and shales of the lower Coal-Measures form the north-facing escarpment of the Boston mountains. Beneath the Coal-Measure rocks are the limestones and cherts of the Lower Carboniferous; and these rest upon Silurian and Ordovician beds. The uppermost beds (Coal-Measures) have been cut into by erosion along the mountain-slopes so that their edges or outcrops have a meandering or dendritic form. The same thing happens with the Lower Carboniferous beds; but these, haying been more or less protected by the overlying Coal-Measured, have broader bases, and cover a much larger area. In places,

Jan 1, 1902

By F. L. Ransome

The following paper aims to present in a much condensed form the salient results of a detailed geological study of the Bisbee quadrangle, Arizona, carried on during the latter part of the year 1902. It is essentially an abstract of the final official report which will shortly appear in the series of professional papers of the U. S. Geological Survey, accompanied by maps, sections and illustrations. I. Geography. The Bisbee quadrangle, which includes the Warren mining district, lies in Cochise county in the southeastern part of Arizona. It is inclosed between the meridians 109" 45' and 110" 00' and the parallels 31" 30' and 31" 201, the latter being locally the Mexican boundarg line. The area of the quadrangle is about 170 square miles, and includes the southeastern half of the Mule Mountains, one of the smaller of the isolated ranges characteristic of this part of Arizona. The Mule Mountains, while less markedly linear than the Dragoon, Huachuca, Chiricahua, and other neighboring ranges, have a general NW-SE. trend. They may be considered as extending from the old mining town of Tombstone to the Mexican border, a distance of about 30 miles. On the northwest they are separated by the broad, flat floor of Sulphur Spring Valley from the Chiricahua Range, and on the southeast by the similar broad valley of the Rio San Pedro from the Huachuca Range. The maximum width of the range is about 12 miles, and its greatest elevation attained by Mt. Ballard, west of Bisbee, is 7,400 ft. above sea-level. An index-map, showing the geographical position of the Bisbee quadrangle, is shown in Fig. 1. The town of Bisbee (Fig. 2), with an estimated population of 6,000, is crowded into a few narrow confluent ravines near the

Jan 1, 1904

By R. A. Sharma, F. D. Richardson

Manganese oxide acitivities and sulfide capacities have been measured at 1650°C in mixtures of MnO + A1203 and MnO + SiO2 - Al2O3. Sulfide capacities have also been measured at 165O0C for melts of MnO + SiO2, MgO + SiO2, MgO + SiO2 + Al2O3, MgO + MnO + SiO2, and SiO2 + Al2O3 and for crystalline CaO. The activity coefficients of the sulfides of manganese and magnesium have been derived where possible. It looks as though the activity coefficients of sulfides are greatest at compositions where the free energies of formation of the silicate mixtures have their maximum negative values. The amphoteric nature of alumina is reflected in the results for the binaries and ternaries in which it is present with silica. The limiting solubility of CaS in CaO at 1650°C is 6.3 x 10-4 mole fraction. THE activities of manganese oxide have been measured in a variety of silicate and aluminate melts by use of the equilibrium (MnO)slag = [Mn]pt .½O2 [l] and the experimental techniques described previously.' Sulfide capacities (CS = wt pct S (PO2/PS2)½) have also been determined in a series of melts, by use of an established method2 which exploits the equilibrium (O°) + ½S2 = (S") . ½O2 [2] If CS and the activity of a metal oxide are known in a melt, the activity coefficient of the metal sulfide can be calculated by use of the equilibrium constant K, for the pure phase reaction MO i ½S2 = MS + ½O2 [3] The activity coefficient of the sulfide is then given by the equation

Jan 1, 1965

By George B. Lee

DURING The Two Years In Which The New Reduction-Works Of The Copper Queen Consolidated Mining Co. Have Been In Operation At Douglas, Ariz., There Has Developed A Remarkable Condition In Regard To The Corrosive Action Of The Water Used To Cool The Jackets Of The Blast-Furnaces. Were It Not For The Many Contradictory Features, It Might Pass As One Of The Unavoidable Troubles Due To The Composition Of The Water. This Water, Obtained From Wells 600 Ft. Deep, Is Also Used In The Steam-Boilers, And Its Composition, As Shown By The Following Analysis, Does Not Indicate The Presence Of Any Ingredient Which Would Explain The Corrosion Grains Per U. S. Gal. Silica, 0.861 Iron Oxide And Alumina, 0.223 Calcium Carbonate, 0.2111 Calcium Sulphate, Magnesium Carbonate, Sodium And Potassium Sulphates, . 14.850 Sodium And Potassium Chlorides, 9.732 Sodium And Potassium Carbonate, 6.452 32.409 The Jackets Are Made Of Inner Plates 0.5 In. Thick And An Outer Plate I In. Thick, With 3-In. Stiffeners Between The Inner And Outer Plates. In From 10 To 12 Months The Inner Plates Have Been Reduced By Corrosion To A Thickness Of From 1/8 To 1/16 In., While The Outer Plate In The Same Time Is Reduced By Less Than 1/16 In., And The Stiffeners Show Very Little Corrosion. The Plates Are Pitted And Eaten Away In Some Places More Than In Others. There Is Practically No Scale Found On The Jackets, But When Cleaned Considerable Iron Oxide Is Found In The Bottoms. With An Action So Marked, Serious Trouble Would Be Expected In The Boilers, But, On The Contrary, A Recent Inspection By a

Mar 1, 1908

By J. A. Ede

The property of the Spring Valley Coal Company, situated in Bureau county, Ill., comprises something more than 30,000 acres of coal-lands, on which have been opened four mines, designated as Nos. 1, 2, 3 and 4. Figs. 1, 2, 3 and 4 are plans of the first three; and Fig. 7 is a view of the surface-plant at No. 4, the workings of which it is not necessary to illustrate, as this mine has been practically merged in No. 2. No. 4 shaft is only 500 feet from No. 2, and both are ventilated by the same fan, and are in the same circle of air-supply. In speaking of No. 2, we now include No. 4. The system pursued in all the mines is " long-wall advancing," and the shafts are all vertical. The seam worked is locally and commercially known, in the Illinois series, as No. 3; but its position in the geological series is that of No. 2. It averages in thickness about 42 inches, arid has no partings, but mines in rectangular lumps, which stand a large amount of handling before breaking. An analysis made from Colliery No. 1 gave the following : Per cent. Moisture,.......... 1.45 Volatile combustible matter,.47.27 Fixed carbon,.........41.97 Sulphur,.........2.46 Ash,....... .. .. .. 6.85 Plate 6 shows a photographic view of this seam. The staff seen in the view is 37 inches long. The table on page 188, recorded in my office, which I presume to be correct, may be of interest. The bottom is fire-clay, varying in thickness from 6 to 24 inches. It affords what is considered good mining-ground. The roof immediately above the coal is a dark shale, lying in small bands, from 4 to 9 inches in thickness. Between the

Jan 1, 1900

By Carls Benedicks

It is well known by every one who has had to deal with boiler tubes that these are often seriously affected by a sort of corrosion, occurring as a local pitting, that frequently causes a perforation of the tube in a rather short time. The characteristic appearance of this corrosion is shown in Fig. 1. A very similar corrosion occurs in condenser tubes (Fig. 2).l A study of the microstructure or local chemical composition of the metal (iron 70:30 brass) fails to reveal any cause for this pitting. Of course one might possibly assume the starting point to be some oxide particle, causing an electrolytic local action, but this in no way explains the continued corrosion, progressing even when the assumed oxide particle must have disappeared. By the excellent work done by the Corrosion Research Committee of the Institute of Metals, and communicated, in October, 1923, to the Institution of Engineers and Shipbuilders in Newcastle-on-tyne, stress was laid on the faot that a content of entangled air has a very obnoxious effect. In the following correspondence, Sir George Goodwin stated that "engineers have, for a long time past, regarded air as the big enemy to be fought against in all questions of corrosion'72 and Kenneth Fraser pointed out that the most vital point is "the avoidance or removal of possibly the chief cause of present day corrosion, i. e. entrapped air and gases brought out of solution."3 In their reply, however, the authors state that they had "never for a moment believed that entangled air was responsible for the beginnings of corrosion, and express the opinion that the gradual liberation of air could not account for localized corro~ion."~ On consulting the many textbooks on corrosion, as that

Jan 1, 1925

By Phillip B. Bucky, R. S. Taborelli

The term "longwall mining" is best known to coal men, although modifications of the method are continually being used in other fields. Longwall mining is of interest today because it makes for greater inechanization and better supervision at the working face, and therefore lower production costs and increased safety. It is an approach to the factory system of production, the high efficiency of which as compared to that in mines is well known. There is available an accumulation of experience regarding this work but coordination of experience is lacking and this series of experiments was undertaken to help serve this purpose. Model experiments were used for reasons of safety, cost and time, and because it has been previously shown1,2,3 that a scalar inodel built of the same material as the prototype will behave in a manner similar to that of the prototype, with time effects the same, if the effective weight of the model is increased in the same proportion as its linear dimenbions are decreased. This is accomplished by substituting a centrifugal for the gravitational field; i.e., placing the model in a centrifuge and controlling the strength of the centrifugal field by varying the rate of rotation. Many factors affect the behavior of the geologic material overlying a bed, therefore results and conclusions contained in this paper apply only to the conditions presented herein. Longwall Mining What Is Longwall Mining?—Agreement should be reached as to what constitutes longwall mining and therefore what constitutes a longwall face. Let longwall mining be defined as the mining procedure in which the roof and overlying bed breaks tend to parallel the working face. In the ordinary stope or room-and-pillar mining the roof breaks tend to

Jan 1, 1938

By Phillip B. Bucky, R. S. Taborelli

The term "longwall mining" is best known to coal men, although modifications of the method are continually being used in other fields. Longwall mining is of interest today because it makes for greater inechanization and better supervision at the working face, and therefore lower production costs and increased safety. It is an approach to the factory system of production, the high efficiency of which as compared to that in mines is well known. There is available an accumulation of experience regarding this work but coordination of experience is lacking and this series of experiments was undertaken to help serve this purpose. Model experiments were used for reasons of safety, cost and time, and because it has been previously shown1,2,3 that a scalar inodel built of the same material as the prototype will behave in a manner similar to that of the prototype, with time effects the same, if the effective weight of the model is increased in the same proportion as its linear dimenbions are decreased. This is accomplished by substituting a centrifugal for the gravitational field; i.e., placing the model in a centrifuge and controlling the strength of the centrifugal field by varying the rate of rotation. Many factors affect the behavior of the geologic material overlying a bed, therefore results and conclusions contained in this paper apply only to the conditions presented herein. Longwall Mining What Is Longwall Mining?—Agreement should be reached as to what constitutes longwall mining and therefore what constitutes a longwall face. Let longwall mining be defined as the mining procedure in which the roof and overlying bed breaks tend to parallel the working face. In the ordinary stope or room-and-pillar mining the roof breaks tend to

Jan 1, 1938

By Howard Smith

AT the meeting of this Institute in February 1933, I presented a paper on potash development in southeastern New Mexico1, which contained a brief review of the Geological Survey's 20-year search for commercial sources of soluble potash minerals and of the events, that led to the discovery, exploration, and first development of the deposits in that state. As a more comprehensive review of the subject was published in December2, the present paper is intended only to discuss recent developments in the domestic potash industry, particularly in New Mexico. A summary of the findings of potash in the Permian Basin, by. G: R. Mansfield and W. B. Lang, geologists of the United States Geological Survey, is now in process of publication by the University of Texas and will be omitted from this paper. In New Mexico prospecting for potassium salts during the past two years has increased materially the known area .of commercial deposits; development has resulted in an increase from one to three in the number of shafts and the starting of a fourth; an increase of annual productive capacity to 1,000,000 tons of crude salts, or 250,000 tons of K20; and an increase in annual refining capacity to 140,000 tons of muriate of 62.5 per cent grade. Construction has been completed to increase still further the production of high-grade salts. In California the American Potash & Chemical Co., operating on Searles Lake brines, has increased its plant capacity from about 100,000 tons to 180,000 tons of muriate a year and is now producing soda ash and salt cake in addition to potash and borax. Potash production from cement-plant and industrial-alcohol wastes remains unimportant.

Jan 1, 1935

By R. L. Wilcox, M. L. Fuller

Owing to the nature of the die-casting process, fresllly cast alloys are undoubtedly not at equilibrium from the standpoint of alloy phase relationships. After casting, therefore, they tend to undergo phase changes, with the ultimate effeet of reaching a state of equilibrium at the aging temperature, beyond which no fnrther change takes place. This phase alteration undoubtedly is one of the primary causes of the changes in dimensions and physical properties that zinc-alloy die castings undergo during aging. It is planned to report on this problem in a series of papers of which this is the first. The writers have made a study of commercial zinc die-casting alloys over a period of several years, utilizing the X-ray diffraction technic of determining the phase composition changes in the alloys. Up to the present, two principal phase changes have been observed which are capable of causing dimensional changes: (I) the segregation of secondary constituents from the zinc-base solid solution and (2) the beta aluminum-zinc decomposition. The latter is the subject of the present paper and studies on the former will be reported upon at a future time. Scope of Study In the present investigation a special technic for the study of the beta phase in zinc-alloy die castings has been developed, making possible the determination of the period of existence of the beta phase after casting. The pure beta constituent and its decomposition have been studied in detail. The effect of magnesium and copper on the velocity of the decomposition is reported. The heat of decomposition, the eutectoid temperature arid the accompanying density change have been measured. The density change lias been calculated from data on crystal structure and the result thus obtained has been compared with the actual change.

Jan 1, 1935

By R. L. Wilcox, M. L. Fuller

Owing to the nature of the die-casting process, fresllly cast alloys are undoubtedly not at equilibrium from the standpoint of alloy phase relationships. After casting, therefore, they tend to undergo phase changes, with the ultimate effeet of reaching a state of equilibrium at the aging temperature, beyond which no fnrther change takes place. This phase alteration undoubtedly is one of the primary causes of the changes in dimensions and physical properties that zinc-alloy die castings undergo during aging. It is planned to report on this problem in a series of papers of which this is the first. The writers have made a study of commercial zinc die-casting alloys over a period of several years, utilizing the X-ray diffraction technic of determining the phase composition changes in the alloys. Up to the present, two principal phase changes have been observed which are capable of causing dimensional changes: (I) the segregation of secondary constituents from the zinc-base solid solution and (2) the beta aluminum-zinc decomposition. The latter is the subject of the present paper and studies on the former will be reported upon at a future time. Scope of Study In the present investigation a special technic for the study of the beta phase in zinc-alloy die castings has been developed, making possible the determination of the period of existence of the beta phase after casting. The pure beta constituent and its decomposition have been studied in detail. The effect of magnesium and copper on the velocity of the decomposition is reported. The heat of decomposition, the eutectoid temperature arid the accompanying density change have been measured. The density change lias been calculated from data on crystal structure and the result thus obtained has been compared with the actual change.

Jan 1, 1935