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Sponsored by the Utah Section of AIME, the 1960 Annual Rocky Mountain Minerals Conference brought more than 500 members of the mineral industry to the conference rooms of the Newhouse Hotel in Salt Lake City during the period October 5 to October 7. Under the overall supervision of J. M. Ehrhorn, general chairman, and H. E. Wright, assistant general chairman, the Conference offered 14 papers of technical interest in four sessions during the first two days, and it culminated in the Exploration Symposium held on the morning of October 7. The opening session of the Conference, meeting on the morning of October 5, heard R. P. Work, utility engineer of the Mountain Fuel Supply Co., discuss the growth and economic factors related to the use of natural gas in Utah. In his paper entitled Natural Gas Market In Utah, Mr. Work emphasized the very good prospects of natural gas serving almost all parts of that state. He mentioned that recently the El Paso pipeline, built to serve the Pacific Northwest with gas from Texas, has permitted natural gas to be available to Eastern Utah, and a tentatively planned pipeline from Green River, Wyo. to Southern California will bring natural gas to the central and southeast areas of the state.

Jan 11, 1960

By William P. Blake

(Canal Zone Meeting, November, 1910.) A DEPOSIT of manganese-ore near Tucson, Ariz., merits notice by reason of the peculiar form in which it occurs, and as a striking. example of ore-deposition by vadose upward capillary flow of metal-bearing solutions with concentration at the surface of the country-rock. This deposit occurs at the northern end of the Coyote mountains, about 40 miles west of Tucson, upon the outcropping beds of porphyritic rock, which appear to be partly-metamorphosed strata of volcanic tufa, probably of late Secondary or of Tertiary age. The strata dip northward at a low angle, and present a series of basset-edges in parallel lines of outcrop, east and west, facing the south and extending over many acres. Successive groups of these outcrops, from 5 to 20 ft. in breadth, are coated with oxides of manganese in lustrous black films and crusts, shining in the sunlight like polished ebony, and covering the whole surface of the rock above the soil. Seen at a little distance, these croppings look like solid ledges of massive and pure ore; but closer inspection and a few blows of the hammer reveal their true nature as a superficial coating allied in origin to the blackened shining surface of rocks exposed in desert-regions, familiarly known as " desert paint" or "desert varnish,"' similar to the phenomena described by me in a former paper, but much thicker and heavier. * By reason of the death of the distinguished author, this communication, probably his last communication to technical literature, is published without revision of the proofs by him. A term first given y G. K. Gilbert. See Rocks, Rock-Weathering, and Soil; by George P. Merrill, p. 256 (New York, 1897). Superficial Blackening and Discoloration of Rocks, Especially in Desert Regions, Trans., xxxv., 371 (1905).

Sep 1, 1910

By Henry Mulryan

DIATOMS are microscopic aquatic plants of the order Bacillariaceae. They are unicellular plants with skeletons made up of amorphous opaline silica. The skeletons show highly ornate, complicated geometrical designs. Diatoms live in water virtually everywhere. They are found in clean sea water, brackish water, and fresh-water lakes and ponds. When conditions are right, diatoms propagate by subdivision in huge numbers. Alkalinity, temperature, and the presence of high concentrations of silica in the water largely control diatom life. When the diatoms die the skeletons drop to the bottom of their habitat to form oozes of vary-ing thicknesses. DIATOMITES Diatomite, or diatomaceous earth, is composed essentially of the siliceous remains of the diatoms, although other organic skeletons are also present, especially in sea-water deposits where radiolaria, sponges and silico-flagellates are common. Impurities are generally carbonaceous material, fine-grained silt, volcanic ash and dust, and occasional coarse grains of sand. Diatomites are marine, brackish, or fresh-water, depending upon types of diatoms and their method of deposition.

Jan 1, 1939

Jan 1, 1915

By D. J. McAdam

As shown in three recent papers by the author, in two papers by McAdam and Mebs, and in a paper by McAdam, Mebs, and Geil," the technical cohesive strength of a metal, in any particular state as regards mechanical treatment and heat-treatment, cannot be represented by a single stress value, but must be represented by a diagram with the principal stressest as coordinates. Each point on the boundary of such a diagram represents a technical cohesion limit. The technical cohesive strength thus comprises an infinite number of technical cohesion limits, each representing fracture under a specific stress combination. Moreover, neither the yield strength1 nor the ultimate strength can be represented completely by a single stress value, but must be represented by a diagram with the principal stresses as coordinates. All combinations of the principal stresses may be classified in three groups as illustrated by Fig. I. Fig. Ia shows three typical stress combinations with no two principal stresses equal. The magnitude of each principal stress is indicated qualitatively by the length of the arrow. Arrows pointing away from the cube indicate tensile stresses; arrows pointing toward the cube indicate compressive stresses. Typical stress combinations with two principal stresses equal are illustrated in Figs. rb and Ic. Such stress combinations would be produced by subjecting a cylinder to combinations of uniform axial and radial stresses. The uniform radial stress may be resolved into two equal principal stresses. with the mutually perpendicular directions rotatable around the axis of the cylinder. Fig. ib shows stress combinations with Sz equal to The greatest principal stress is in the axial direction, and the stress combination tends to cause either absolute or relative increase in length.* Fig. u shows stress combinations with S2 equal to St. The greatest principal stress is in the radial direction, and the combination tends to cause either absolute or relative decrease in length. The complete representation of either technical cohesive strength, yield strength, or ultimate strength generally requires a three-dimensional diagram. When two of the principal stresses are kept equal, however, the strength of a metal may be represented by a two-dimensional diagram with the coordinates representing the axial and radial stresses.6-II In this paper, attention will be confined almost entirely to stress combinations with two of the prin-

Jan 1, 1945

By Chester A. Fulton

SUPPLYING as it does a necessity for healthy animal and vegetable phosphate production is a most important industry. We human beings also are animal as this war so surely proves. Unlike many other elements no substitnite is available for phosphorus or its compounds. Marvelous as are modern plastics none can lake the place of phosphorus in making hone structures. As meassured in these times the phosphate industry is not a large industry. Output of phosphate rock, the original source of our agricultural and ,chemical phophates amounts to only some twelve million long tons per annum in the entire world. Phosphates are compounds of phosphorus, which is always found in nature combined with other elements. It never occurs in nature as such. The first choice of the element phosphorus is tie itself strongly to oxygen and then to water moisture - thus becomeing phosphlic acid. This phosphoric acid in turn hunts around for a base such as lime for instance and together they make phosphate of lime.

Jan 1, 1944

By L. L. Oriard

In order to predict the influence of blasting on slopes, one must first understand the action of explosives, the manner in which rock is broken or displaced, and how seismic waves are transmitted, and the nature of these seismic waves. In this paper, the author describes the action of high explosives on rock masses, beginning at the source of the explosion, extending through the zone of rupture to a distance where only elastic waves of low energy persist. The paper describes the relationships between explosives charge quantities and distances, including the character and intensity of the seismic waves in various types of terrain. In looking at the analysis of slopes subjected to seismic waves, it has been common practice to assume a simplified model in which the anticipated acceleration is applied horizontally to the slope as an equivalent static force, or a model in which there is a rigid base subjected to mechanical shaking. Such models do not accurately portray blasting activity taking place within or near the slope in question. In dealing with blasting effects, it is important to under- stand seismic wave types, wave lengths, attenuation and transmission paths, as well as vibration intensity. In most cases, those slopes that are the least stable under static loading will also be the least stable under dynamic loading, although there may be rare exceptions. Thus, the more that is known about a slope statically, the better will be the assessment of it dynamically.

Jan 1, 1983

By John H. Schissler

INTRODUCTION AND SUMMARY Complex copper-lead-zinc ore is mined from underground workings high in the Western Cordillera of the Andes mountains about 100 km in a stralght line north of the city of Arequipa in southern Peru. The Madrigal mine is situated in a steep-walled canyon into which the six operating levels "daylight". Production is from cut-and-fill stopes currently producing approximately 740 dry metric tons per day. The Santa Rosa vein, the most important producer in the district, outcrops for a distance of about 4 km, bearing N 75º W and dipping about 70º NE. In places the vein splits into two or three branches; widths of each vary between 1 and 4 m and total mineralized widths of up to over 8 m occur. Principal ore minerals are chalcopyrite, galena and sphalerite. Ore reserve grades for the Madrigal mine average about 1.45% Cu, 2.6% Pb and 5.0% Zn, 2.9 ozAg per metric ton. [Compania] Minera del Madrigal is a California limited partnership; the general partner and operator is [Compania] Madrigal, a wholly-owned subsidiary of Homestake Mining Company. HISTORY Shallow workings found on the Santa Rosa vein were probably made by the Spaniards during colonial times in their search for

Jan 1, 1977

By Carl Swartz

METALLURGISTS differ considerably in their opinions regarding the effect, if any, of small amounts of iron pyrites, or other iron compounds on zinc sulfide ores during the roasting operation. As a result, the literature on this subject expresses many conflicting ideas. The ore, previously crushed to pass through a one-millimeter screen, dries in the roasting kiln, losing water up to 200° to 300° C. At 150° C. iron pyrites begin to lose sulfur. As the temperature increases, while the ore is passing to the hotter part of the furnace, the sulfur burns to sulfur dioxide, leaving the metals as zinc oxide and ferric oxide. These two substances then interact to form zinc ferrite, a compound, yellow brown in, color, having the general characteristics of a spinet Like magnetite, another spinel, zinc ferrite is insoluble in alkalis and dilute acids. As a result, when leached with 10 per cent. sulfuric acid solution zinc values tied up in this compound remain behind. HISTORY In the electrolytic recovery of zinc from its ores, the roasted ores are usually leached with a 10 per cent. sulfuric acid solution. When the zinc ore contains iron pyrites as an impurity in an appreciable amount, the actual yield of metallic zinc is much lower than a theoretical calculation would indicate. Further, losses of zinc are, in a rough way, directly proportional to the amount of iron pyrites or other iron compounds present. When the iron is present in the ore in an isomorphous relation to the zinc, as in the case of a marmatite, a greater amount of zinc remains insoluble than when present as a true pyrite or marcasite. Work on the insoluble residues obtained from leaching of the calcines shows that the zinc lost is intimately tied up in this residue. Some investigators have suggested a definite compound, such as zinc ferrite, others merely a mixture of zinc and iron compounds.

Jan 1, 1927

By AIME AIME

THE following Officers, Directors, and guests were present: Herbert Hoover, A. R. Ledoux, Henry S. Drinker, Edwin Ludlow, Samuel A. Taylor, Charles F: Rand, William M. Corse, Arthur S.. Dwight, Glen H. Clevenger, L. W. Francis, F. G. Cottrell, Bradley Stoughton, Percy E. Barbour, E. P. Mathewson, Dorsey A. Lyon, Archibald Douglas, A. D. Flinn, RobertLinton, James F. Kemp, William Y. Westervelt, J. W. Richards, W. L. Saunders, George Otis Smith, Thomas T. Read, J..C. Murray, Ralph Arnold. A Committee on Mine Equipment was appointed composed as follows: Graham Bright, chairman, William Kelly, Howard N. Eavenson, R. E. Hobart, and S. P. Rumsey. B. D. Saklatwalla was added to the Committee on Miscellaneous Metals and W. Spencer Hutchinson was added to the Committee on Mining Geology. A revised budget for 1921 was approved. A petition duly signed to amend Section 1., of Article III of the Constitution, increasing the initiation fees from ten dollars to twenty dollars, was approved by the Board.

Jan 1, 1920

By H. M. Day, C. H. Mathewson

THE constitution of the system silver-mercury has attracted the attention of many investigators during the last two decades, but since their results are for the most part in poor agreement, there is little need for a review of their individual contributions. It remained for the very careful thermal and microscopic investigation of Murphy' in 1931 to give the constitutional diagram in its present and unquestioned form, which is shown in Fig. 1. He devised methods for taking cooling curves on alloys under high pressures and for the microscopic observation of alloys which contained liquid mercury as a structural constituent at ordinary temperatures. The compositions of the intermediate phases were confirmed and supplemented through X-ray analyses by Preston2 and Stenbeck.3 According to Murphy, at 276° C. silver is able to dissolve 44 to 45 weight per cent of mercury, which may increase at lower temperatures to about 50 per cent. Preston concluded that the saturation boundary occurred at 46 ± 2 per cent at 100° C. From the values reported in the literature, these are the only ones that may be accepted as lying even in. the right region. PREPARATION OF ALLOYS The silver used in the present investigation was supplied by the United States Metals Refining Co. through the courtesy of the Committee on Industrial Uses of Silver and, since a complete spectrographic and chemical analysis was furnished, no attempt was made to purify it or to further establish the impurities present. The analyses reported by the company are shown in Table 1. Milligan4 has found that the magnesium content is probably less than 0.0005 per cent.

Jan 1, 1938

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Jan 1, 1961

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Jan 1, 1946

By A. Perry Thompson

I. GENERAL DISTRIBUTIONS APPEARANCE, AND RELATIONS MINING in Butte has seldom encountered covellite in commercial quantities. The notable occurrences, extending vertically and laterally perhaps several hundred feet, presented scattered, bladed lenses of this mineral in a matrix of quartz, pyrite, enargite, bornite, and chalcocite. But under the microscope covellite is seen to be widespread in the Butte ores, though in such small quantity that megascopic examination will not discover it. In early mining operations covellite was found in the Gray Rock vein, a member of the Blue vein system. As described by Sales,1 it persisted as an occasional ore mineral, associated with quartz, pyrite, tetrahedrite, bornite, chalcocite, and minor amounts of sphalerite, from the 700-ft. to the 1,200-ft. level of the East Gray Rock and Diamond mines. Crushed quartz-monzonite and later quartz completed the vein filling between

Jan 4, 1915

By Thomas T. Read

Jan 1, 1913

By R. F. Mehl, C. S. Barrett, A. G. Guy

INTRODUCTION IN the last few years this laboratory has published a series of papers on the mecha¬nism of age -hardening.14,1,6,11,20 Briefly stated it has been proposed that hardening is caused by lattice strains created by lat¬tice coherency between matrix and precipi¬tate; much experimental evidence has been advanced to support this thesis. The system Cu-Be is an attractive one to study. It is a system that exhibits marked age hardening; it ought to be subject to the type of analysis of structural changes hitherto explored and it is a prominent example of "discontinuous precipitation," which, though studied in other cases, 6,20 remains largely unexplained. This research shows that hardening in the Cu-Be system proceeds essentially as proposed earlier.14 Guinier-Preston zones have been observed to form on the {100) planes of the matrix; no transition lattice was found. Aging and overaging were ob¬served to occur most rapidly in the region of discontinuous precipitation-the grain boundary-apparently accelerated there by strain. The Constitution of the Cu-Be System The Cu-Be constitution diagram is shown in Fig I. The structure of the ? phase was determined by Misch16 as of the caesium-chloride type with a lattice con¬stant of 2.598 Å High temperature X ray photograms of 7.2 pct Be alloy made by Kossolapow and Trapesnikow13 led them to conclude that the structure of the P phase is simply disordered body-centered cubic with [ao] = 2.79 Å at 750°C. Previous Work The initial work on the age-hardening of Cu-Be alloys was that of Masing, Dahl, Holm, and Haase. Their numerous papers were published in book form in 1929, sub¬sequently translated.18 The effects of Be content, solution temperature, aging tem¬perature, and cold work on the hardness developed in these alloys were studied. An initial decrease in the electrical conduc¬tivity was observed when strips of a 2.5 pct Be alloy were aged at temperatures from 200 to 350°C; a wire of the same analysis failed to exhibit this decrease when aged at 350°C. A volume decrease of 0.6 pct oc¬curred during aging at 250°C. Microscopic investigations of quenched and aged alloys disclosed a regularly ori¬ented "striping" (ripples) on the a and on the ß grains. In the case of the ß the cause of the striping was held to be decomposition

Jan 1, 1948

By JESSE L. MAURY

DEVELOPMENT of new gold mines in Canada since the price of that metal was increased in 1932 and 1933 has been of interest and importance to many of us. The day-by-day story has given an impression of aggressive effort and enough good luck so that the spirit of enterprise has been encouraged. It is the purpose of this article to report the results of a statistical appraisal which give emphatic numerical confirmation to this impression, together with certain side lights on the costs of development and equipment of new mines. The data presented have been taken from all readily available published sources up to the close of 1938 and are representative of that year. A. B. Bower did a large part .of the spadework and Weston Thomas offered many helpful suggestions.

Jan 1, 1939

By H. E. Brauer

PART I INTRODUCTION Among the zinc base alloys used for casting in metal moulds, particularly die casting, those alloys containing aluminum usually together with copper, are probably the most widely used. The reason lies in their desirable mechanical properties and the fluidity and absence of hot shortness which facilitate casting. Objection to the use of these alloys may bee raised on account of the rather frequent instances of failure of a type variously described as disintegration, exfoliation and intercrystalline corrosion. In all cases which have come to our knowledge where the conditions of service were known, failure has occurred upon exposure to moisture and heat varying from a hot moist atmosphere to high pressure steam. Moreover, the alloys described in all such cases contain impurities or alloying metals which the present authors have found to have enormous accelerating effects on intercrystalline oxidation in zinc-aluminum alloys. Thus Williams1 experimented with an alloy containing a large percentage of tin exposed in Cuba. Bauer2 reports failure of a boiler plug containing over 1 per cent. of impurities, doubtless lead for the most part, and Rawdon's3 examinations were made on an alloy containing 0.4 per cent. lead also exposed to the Tropics. No thorough investigation of the nature and cause of this type of failure has been made heretofore, so far as the authors are aware, although Rawdon correctly classified it as internal oxidation. We have, therefore, carried out this investigation in order to determine the exact nature of this phenomenon and the effect of other metals present as impurities or intentional additions in accelerating or-retarding it. In the appendix we include a considerable amount of data which may be valuable in selecting an alloy combining good physical properties with high resistance to oxidation.

Jan 8, 1922

By S. R. Goodman, Hsun Hu

The rolling texture transition in copper as a function of deformation temperature is found to be quite similar to that in high-purity silver. The ordinary copper type texture changes gradually to the brass type, accompanied by an increase in the stacking fault frequency, as the temperature of deformation decreases. The rolling textures obtained at low temperatures and the corresponding annealing textures compare remarkably well with the ordinary rolling and annealing textures of low-zinc brasses. Furthermore, it is also found that the observed stacking fault energies of copper specimens deformed at low temperatures correspond closely with those of low-zinc brasses, as deduced from measurements of the dislocation nodes. These results are consistent with the idea that texture transition may be significantly dependent on the stacking fault energy. It was shown in a series of previous publications1"3 that the rolling texture of high-purity silver changes gradually from the common silver type (or the brass type) to the copper type* with increasing temperature *The silver or brass type rolling textures are commonly described as (110)[112],4,5 whereas the copper type rolling textures are mainly (123) [a121 and (146)[211].5 Other ideal orientations have been used by various investigators for the copper type rolling textures, but the actual difference among these ideal orientations is rather small. of deformation, and that such texture transition can be correlated with the change in stacking fault frequency as a function of rolling temperature. Furthermore, it was shown that the formation of annealing textures in high-purity silver from the various rolling textures obtained during the course of texture transition depends entirely upon the deformation texture. From a common silver type or brass type rolling texture (such as produced by rolling at 0" or at 50° C) the recrystallization texture is mainly (120)[211], which is quite different from the recrystallization texture of brass.* However, for both ma- terials the orientation relationship between the rolling texture and the recrystallization texture can be expressed in terms of similar rotations around [Ill.] axes of approximately 30 or 35 deg. They differ in that the [Ill] rotational axes are different. In the case of high-purity silver, the axes of rotation are the two (111) poles near the plane normal of the deformed specimen with a (11l)[112] type rolling texture, whereas in brass, they are the (111) poles near the direction of rolling. For high-purity silver with a predominantly copper type rolling texture (such as produced by rolling at 150° or 200°C) the recrystallization texture is mainly (100)[001], or the cube texture, plus its twin orientations. It was shown previously6 that such reorientation observed in copper or aluminum can be described as [Ill] rotations of 30 to 40 deg. For intermediate cases, i.e., when the rolling textures are composed of a

Jan 1, 1963

By W. F. Mullen, C. W. Stickler

WITH few exceptions, unit operations in the Pennsylvania slate industry in 1950 did not differ appreciably from production methods described by Behrel and Bowles2-4 several decades ago. Many traditionally picturesque but relatively inefficient hand operations continued to contribute to high operating costs in an industry in which the margin of profit, for various reasons, was admittedly low. As part of a general program in which the Pennsylvania State College has been assisting the slate industry to solve some of its problems, time and method studies were used in an effort to determine the bottlenecks of production flow. The results are as applicable to other stone industries as they are to slate. A study of the basic elements in the production of roofing slate, structural slate, and slate blackboards among selected slate producers revealed comparatively few refinements. Any marked difference in operating method was characterized largely by the available equipment, a noticeable difference in the working properties of the rock quarried by a particular company, and by either the habit thinking or ingenuity of the individual operators. With the hope that significant economies in manufacture might result, all the unit operations were broken down into elements for study and analysis. The greater part of the study encompassed those operations from the quarry rim to the finished product; however, to obtain a reasonable synthesis of time allotments per operation, several analyses of quarrying from the finish of the wire saw cut are included for reference. The complete study of quarrying made by Bowles several years ago resulted in the introduction of the wire saw into the operation; there appears to be a need for as fundamental a change in the processing of finished slate as the wire saw was in the quarrying process. Fig. 1 illustrates the flowsheet of quarried rock from the parent bed to the quarry rim with the basic elements which contribute to the difficulty of removing slate from the ground. In Pennsylvania roofing slate is produced by one of three procedures, many operations of which are quite similar. In the traditional or classical method the quarried rock is reduced by sculping and auxiliary manual treatment to workable size and then is split and dressed (trimmed to size) in the conventional shanty. Archaic as this method might appear, there are several elements that result in substantial savings over more mechanized operations. In a modified version of this method, the block is reduced by sawing and gouging preparatory to splitting and dressing in indoor stations. This method is particularly adaptable to rock which fractures unevenly by conventional sculping methods. In the third and more modern method, reduced block received from the block maker is diamond-sawed to length and finished on a production line. Fig. 2 illustrates the flow pattern in each case. In the modified and more modern plans, dressing is done on mechanically-operated trimming machines, which appreciably reduce the fatigue factor of the operator. However, it should be noted that it is advantageous for the operator to be able to control the speed of the knife to prevent breakage of certain classes of stock. In the classical plan the splitter and dresser normally act as blockmakers also and carry their eighter slabs (equivalent in thickness to eight shingles) into the shanties themselves, all of which adds to fatigue and reduced efficiency. The extremely low investment and operating expense of the classical method has undoubtedly been of paramount importance in its continuation. Production of Mill Stock The production of mill stock is accomplished by less picturesque methods than enter into the production of roofing slate but it is, in the main, relatively more efficient because of the increased use of machinery for handling and for finishing. Mill stock can be classified into two categories as far as difference in production method is concerned: structural slate and blackboards. The significant difference in operation is caused largely by the nature of the rock used for each product with the best and easiest cleaved rock being reserved for blackboards to permit the splitting of large slabs to as little as 1/2 in. in thickness. Structural stock, on the other hand, is split into panels no thinner than 11/2 in. and

Jan 1, 1952