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By Frank Robertson Van Horn

In June, 1911, the writer spent a few days in studying the economic geology of the vicinity of Park City. During this rather hurried visit a number of specimens of ore were collected, which have since been examind. The results of these investigations show that bournonite (PbCu-SbSa) is present in the ores in greater or less quantity. This fact has never before been reported, as far as can be learned. The failure to recognize this mineral is due to its similarity to tetrahedrite, with which it has probably been confused during a long period of years. Jamesonite (Pb2sb2s6) has been reported from the region in a rather doubtful manner, but the writer has seen it in notable amounts from several mines, and can offer the first analysis of this mineral from the district. Calamine (HzZn2SiO5) was found at one mine and has never been ecognized and reported from the district. Geogbaphy and Geology Park City, Utah, is located at an elevation of about 7,000 ft. above sea level on the eastern slope of the Wasatch mountains. It is situated approximately 25 miles southeast of Salt Lake City. ' The geology and ore deposits have been described in detail by Bout well and Woolsey.' The mines visited are situated south-southeast from the town. The Silver King Coalition mine is located in Woodside gulch about 1 mile southeast of Park City, at an altitude of about 8,100 ft. The other mines visited were the Daly West and Quincy, which are in Empire canyon about 2 miles sontheast of the town, at elevations of 8,300 to 8,500 ft. respectively. The Daly Judge tunnel goes into the mountain from Empire canyon about 1 mile south of the city, at an altitude of 7,700ft.

Jan 1, 1915

By W. A. Hooker

This portion of Mexico is quite beyond the ordinary routes .of travel, and is seldom visited. Its mines have not the record of enormous wealth which has recently attracted foreign capital to other parts of the republic; but for many centuries it has been a mining country, and at some periods evidently a productive one. In 1881 the writer visited the State and spent some time in the inspection of the mines. The absence of published information regarding its mining industry is his apology for presenting to the Institute these notes on the subject. Oaxaca is, with one exception (Chiapas), the most southerly of the Mexican States. It extends from latitude 18o 20' to 15' 45' N.— about 180 miles, by some 300 miles, in an east and west direction, and embraces a large part of the Isthmus of Tehuantepec. The coast-line is wholly on the Pacific. The State has an area of 27,470 square miles, nearly that of the State of Maine, and a population estimated at one million, or thirty-six to the square mile. The great continental Cordillera which farther north and west expands into broad table-lands, is here converged into narrower limits and occupies the greater portion of the country; the main

Jan 1, 1887

By Holt, Grover J.

PRIOR to :1937 any discussion of mining and transportation in the iron mines of Minnesota would have been limited largely to conventional methods which have been used for years in the iron ore industry. Today, however, an inspection trip to the crest of almost any open pit on the ranges will re- veal great progress underground mining and the transportation of underground ore have also developed rapidly and if and when underground mining of iron ore again becomes generally economically feasible; these mining methods will probably witness a transformation equal to that which has taken place in the open pits.

Jan 1, 1941

By Joseph E. Pogue

FOR a number of years the petroleum department of The Chase National Bank has been making a continuing study of the financial aspects of thirty oil companies. (See Pogue and Coqueron, "Financial Analysis of Thirty Oil Companies," pamphlet, The Chase National Bank, November 1945, for data covering eleven years, 1934-1944, and the list of the companies making up the group. See also "Capital Employed in the Petroleum Industry," by the same authors, M&M, November 1944.1 This group represents a large sample of theAmerican petroleum industry, covering about two thirds of the business. Certain aspects of this study concern the capital employed in crude oil production, the main features of which arc presented in this paper.

Jan 1, 1946

By George F. Kunz

THE recently discovered occurrence of diamonds near Murfreesboro, Pike county, Ark., was brought to. our attention by Mr. Samuel W. Reyburn (Trustee for Messrs. C. S. Stifft, A. D. Cohn, August Zinsser, Jr., and himself, owners of the property), through whose courtesy we investigated the locality of the deposit. Prospecting with the diamond-drill is now in active progress ; but mining operations on a large scale have not yet been ordered. Geology.-The geology as well as the petrography of this interesting locality has been well described by Messrs. J. C. Branner and R. N. Brackett.1 Briefly summarized, the igneous rock in which the diamonds are found is a vitreous peridotite, forming a stock or volcanic neck, which has broken up through the Carboniferous and Cretaceous quartzites and sandstones. After an extensive period of erosion, during which an unknown portion of the neck and presumably a previously existent volcanic cone have been removed, the surface was covered with thin beds of Post-Tertiary conglomerate. The volcanic intrusion was accompanied by the formation of several small dikes of a rock much like that of the main body. One of these dikes cuts across the stock, while another cuts the Cretaceous sandstone, but is overlain by the conglomerate, thus giving a datum for the period of intrusion. So far as known, there was little, if any, metamorphism of the country-rock by the igneous magna, which probably followed an approximately vertical course, so that a more or less vertical extension downward of the igneous body to indefinite depths may be expected.

Mar 1, 1908

By Leo Ranney

ANY years ago a prospector came to a Nevada town and built himself a shack. Day after day he searched the hills for gold -but he found none. He closed his shack and hurried north, where a strike had been made. Next he tried to trap the flour gold that floats down the Snake River. He panned the black sands along the Oregon coast. He ranged over the mountains and up the gulches of far-off Alaska. At last, broken in health, six years ago he came back to his old home in Nevada. There his shack still stood-nobody wanted it. One day he started a garden in the rocky soil that he owned. His spade turned up a chunk of quartz, and in that quartz were stringers of gold. He had found a rich gold vein, running right under his own house. You gas producers who have hurried to Oklahoma, Louisiana, East Texas, South Texas, West Texas, even to California to drill wildcat holes a mile or two miles deep-why not, like the old gold prospector, have a look in your own back yard? Some of your coal seams contain 20,000,000 cu. ft. of natural gas per acre.

Jan 1, 1943

By F. D. Waltman

Under the hot, baking sun, engineers at the AEC's Nevada Test Site have been busy for several years in the sinking of 48-in. diam shafts to depths varying anywhere from 1800 to 4800 ft below the surface. In so doing these men have evolved several new techniques which should be of interest to the mining industry. Surface Facilities Designed For Speed: "Expediency plus efficiency" is a key phrase at the Site. Because of the relatively short duration of actual mining operations, all equipment has been packaged to decrease time and cost of "set up" and "take down". The headframe, designed specifically for use over 48-in. cased shafts, can be erected or dismantled within 48 hours. The back legs are pinned and hinged to the front legs for ease of installation and, when dismantled, for movement to another site with a minimum of delay.

Jan 6, 1966

By John A. E. M. Church

THE prospector's pan was the first implement used for saving gold, and its action is so effective that it has never been equalled for thorough work. Copper plates, blankets, sluices, and amalgamators of several patented designs have thrust it aside, but in spite of all the advances made there is no dispute among experienced men as to the comparative thoroughness of the work done by it and its rivals. When its rivals are doing their best, the pan can take their discarded refuse and prove their inefficiency by producing from it not only gold, but even the mercury which has been lost from the machines themselves. The trouble with the pan has always been that it was only a tool. Man was the machine that moved it. His work was high-priced, the quantity treated small, and it was impossible to use the pan for any but the richest sands. As a consequence the best gold-saving appliance known has been discarded for years and replaced by machines of inferior excellence, but which could more than make up for their limited ability in saving gold by their capacity for treating great quantities of ore. Mr. Peck is one of the old-time amalgamators of the Comstock district, and the first idea of the new machine came to him as he used to pan below the tailrace of his mill. No matter how fine the work of the mill was, the pan invariably proved that better could be done. The tailings always contained gold, silver, and mercury. This state of things is just as true to-day, after all the improvements that have been made, as it was then, and the much-vaunted method of the " Washoe process" consists in extracting 72 per cent. of the gold and silver by one operation, and then repeating this operation half a dozen times to get out about one-third of the remainder. With all the advances of twenty years in milling, there is nothing more crude in metallurgy than the treatment of tailings in many of the large mills of the West.

Jan 1, 1880

BIRINGUCCIO was born in Siena in 1480, the son of Paolo and Lucrezia di Bartolommeo Biringuccio.* He was baptized on October 20 of that year with the given names Vannoccio Vincenzio Austino Luca. His father appears to have been an architect, for in 1504 he was paid 600 scudi for his work on the walls of the Communal Palace and at the same time he was superintendent of streets for the city. The course of Biringuccio's life followed closely the checkered fortunes of the Petrucci family of Siena. A warm supporter of Pandolfo Petrucci, Biringuccio did not falter in his allegiance to the family and their party during his lifetime. It was probably to the protection and patronage of this lord that he was indebted for the opportunity to travel widely through Italy and into Germany during his early years and so to lay the foundation for the extensive knowledge of the subjects he was to describe in the Pirotechnia. In 1507, as he himself indicates (p. 48), he was 'in Friuli and. Carnia in northern Italy after having traveled in Germany,, and he also visited the, brass, works in Milan. After returning to Siena; he was sent by Pandolfo to direct the iron mines in near-by Boccheggiano. When Pandolfo died in 1512 (in which year Biringuccio's s father also died), Biringuccio continued to support the Petrucci family in the person of Pandolfo's son, Borghese, who succeeded, to the rule. Under his patronage, Biringuccio was appointed to a post in: the Armoury of the Siena Commune in 1513. In ISIS a popular uprising forced Borghese and his followers, including Biringuccio, to flee from Siena. Biringuccio and the goldsmith Francesco Castori, head of the mint, were accused of having debased the coinage alloy with the knowledge and consent of Borghese. When he failed to appear in 1516 to answer these charges-which may well have been invented by the opposing political faction-Biringuccio was declared a rebel and was exiled as a traitor to the Republic. He then traveled about Italy, was in Rome and Naples, and visited Sicily in 1517.

Jan 1, 1942

By Y. A. Rocher, J. E. Dorn, L. A. Shepard

Creep activation energies for single aluminum crystals favorably oriented for shear by (010) [101] glide were detemined over the temperature range from 78" to 900°K. Observations of slip bands on the specimen surface were made in conjunction with the investigation. From 78" to 780°K, the activation energies obtained in this imestigation agreed closely with those previously found for creep by (111) [101] slip. Between 78" and 140°K, the activation energy was identified with the Peierls process, while between 260°and 780°K the activation energy was close to that for cross-slip. The coarse wavy slip bands nominally parallel to the (010) plane observed above 260°K were attributed to fine cross-slip. From 800" to 900°K, unusually high apparent activation energies ranging from 28,000 to 54,000 cal per mole were obtained. These apparent activation energies were attributed to re crystallization. AS illustrated in Fig. 1, a recent investigation1 has shown that creep of aluminum single crystals by the (111) [i01] mechanism is controlled by three unique processes, each of which is characterized by a single activation energy which is independent of the applied stress and the creep strain. A comparison of the observed activation energies with theoretically calculated values permits a fairly clear identification of the three operative creep processes. Below 450°K, where the activation energy for creep is 3,400 cal per mole, the deformation is controlled by the Peierls process, the activation energy for creep agreeing well with that calculated by seeger2 for the energy required to nucleate the motion of a dislocation loop against the atomic forces of the lattice. Between 590° and 750°K, the observed activation energy for creep of about 28,000 cal per mole agrees well with the energy necessary to induce cross-slip. Seeger and schoeck3 estimate that the activation energy is about 24,000 cal per mole whereas Friedel4 recently calculated this activation energy to be 28,000 cal per mole. Above 800°K the activation energy of 35,500 cal per mole that was observed for creep agrees well with that estimated for self-diffusion in aluminum.= In this range the operative rate-controlling slip process has been clearly identified as that arising from the climb of edge dislocations. The objective of this investigation is to ascertain whether a single crystal of aluminum favorably oriented for simple shear in the [loll direction on the (010) plane might exhibit uniquely different activation energies for creep from those obtained previously for (111) [101] slip. Whereas the exis- tence of such unique activation energies would constitute incontrover table evidence for new mechanisms of slip, the absence of any new activation energies might suggest that slip of aluminum is confined to the (111) [loll mechanism. Several factors prompted the selection of the (010) [101] orientation for study. First, there are more reported observations of (010) [loll slip than of any other nonoctahe-dral mechanism.8-10Secondly, Chalmers and Martius1l have concluded from considerations of the energies of dislocations that (010) slip is the second most favored mechanism in face-centered-cubic metals. Finally, favorable orientations for simple shear by the (010) [loll mechanism provide the least favored orientation for slip by the (111) [101] mechanism. EXPE-RIMENTAL PRO-CEDURE The high-purity aluminum stock, specimen preparation, shear fixture, extensometry, and experimental technique used in this investigation were the same as those previously reported.' Single-crystal spheres grown from the melt of 99.995 pct pure Al* were _ *The high-purity aluminum used in this investigation was graciously given by the Aluminum Company of America. oriented, carefully machined into dumbbell-shaped shear specimens, annealed, and chemically polished. The finished specimen had a central reduced section 0.190 in. wide and 0.590 in. in diam and 1/4-in. grip sections at both sides, 0.690 in. in diameter. The specimen was oriented in the stainless steel grips of the shear fixture with the (010) plane perpendicular to the dumbbell axis and the [loll direction parallel to the stress axis within 2 deg. Creep activation energies were calculated in the previously described manner1 from determinations of the instantaneous change in shear strain rate produced by an abrupt 15 to 20 deg increase or decrease in test temperature. If is the instantaneous strain rate at strain y and temperature T1, and ?2 the instantaneous rate at y and T2,

Jan 1, 1960

By Michael J. Messel

OF the various minerals that occur in fibrous form known as asbestos, chrysotile is the variety most in demand for commercial uses, and, last year, over 683,000 tons of the various grades were produced in Canada and United States, exclusive of African and Russian production, which figures are uncertain. Production has not been able to keep up with the increased demand, and an acute shortage exists. Canada, Russia, and Africa are still the most important producers. However, Russia consumes most of its production at home and exports very little. The United States consumes over 60 pct of the total production and produces only about 4 pct of the total from deposits in Vermont and small quantities from Arizona. This paper will review mainly, some of the more recent developments concerned with the extraction and processing of this fibrous mineral for various industrial uses, such as textiles, insulation, building materials and brake linings.

Jan 1, 1949

By P. LEROY FOSTER

G EOPHYSICAL prospecting was presented in its several aspects and discussed with much vigor at two sessions during this year's annual meeting of the Institute. The first session was devoted entirely to the presentation and discussion of various technical papers, while the second meeting took the form of a round table conference on the advisability of revising the existing mining laws to recognize the results of geophysical prospecting. This conference was immediately followed by further consideration of technical papers. Each session was well attended and great interest was displayed by everyone present.

Jan 1, 1929

By A. Eilers

A MARKED peculiarity of most of the smelting-works of the Far West is the looseness with which accounts of the operations are kept. Indeed, probably over half of the works do not keep any detailed accounts at all, the yearly gross statement of profit or loss being considered sufficient for all purposes. The reasons for this must apparently be sought in the as yet unsettled state of all business relations, and in the deplorable fact that only in isolated cases educated metallurgists are in charge of the smelting-works. Continual and regular assays of the ores, by-products, and slags, are almost unknown, so that it is impracticable to ascertain, even approximately, the losses in the smelting processes. Of cases where regular accounts are kept of the quantities of ore smelted, of the composition of charges, and of the fuel consumed, I know only two or three. Under these circumstances it is extremely difficult to collect figures which cover the operations for a considerable length of time, and which are so valuable for the metallurgist, who wishes to get an insight into the economy of smelting operations, as shown by practice. Figures obtained by personal observation, which can of course cover only the brief space of the visit of the travelling metallurgist, must, therefore, be made to replace the more valuable data. The writer has had occasion, during the last and the preceding summer, to visit the larger number of the Western lead-smelting works, and offers, in the following pages, such data relating to the economy of lead-smelting in the blast furnace at various works, as he has been able to obtain. The only object in doing so is to place these figures on record, so that they may be from time to time supplemented with other data, which are now wanting. I. EUREKA CONSOLIDATED COMPANY'S SMELTING-WORKS. These works smelt the ores from the mines of the same company on Ruby Hill, Eureka, Nevada. The supply is almost unlimited,

By G. F. Loughlin

Nearly 55 years have elapsed since the U. S. Geological Survey was organized. During this period the mineral industries have grown from infancy or early childhood to well developed maturity, and some mining industries appear to be declining. Decline in mining is even more conspicuous in certain districts, or even states, than in any mining industry as a whole, and discoveries or developments of important new districts have been very few in recent years. Our reserves of most metals and nonmetals are adequate for many years of normal production, subject to changes in rate of exploitation that may be caused by foreign competition and by changes in technology and market conditions; but the declining production of many districts and the scarcity of important new discoveries to compensate for them is cause for some apprehension. It is likely that future production will depend to a considerable extent on deep exploration and on the thorough examination of places in and adjoining existing districts where significant outcrops are lacking and only apparently insignificant geologic features offer encouraging clues—more so than on the discovery of entirely new districts. Even the possible discovery of new districts, which have escaped the intensive search by the nontechnical prospector, must be dependent on geologic information. There is therefore no need for argument as to the value of geology to the mining industry; and the need of continuing to advance the science. The U. S. Geological Survey's past contributions to mining geology, as expressed in its official reports and other publications, are recognized by Ransome in his historical review of mining geology in the Lindgren volume.' These contributions have helped to form the basis of modern mining geology, which has grown rapidly in the last 25 years. This growth has witnessed the organization and maintenance of geologic staffs by mining companies in several districts, and their detailed work, together with the fact that nearly all of the larger mining districts have

Jan 1, 1935

By A. Eilers

COMPOSITION OF CHARGES AND CONSUMPTION OF FUEL AT VARIOUS WORKS. A MARKED peculiarity of most of the smelting-works of the Far West is the looseness with which accounts of the operations are kept. Indeed, probably over half of the works do not keep any detailed accounts at all, the yearly gross statement of profit or loss being considered sufficient for all purposes. The reasons for this must apparently be sought in the as yet unsettled state of all business relations, and in the deplorable fact that only in isolated cases educated metallurgists are in charge of the smelting-works. Continual and regular assays of the ores, by-products, and slags, are almost unknown, so that it is impracticable to ascertain, even approximately, the losses in the smelting processes. Of cases where regular accounts are kept of the quantities of ore smelted, of the composition of charges, and of the fuel consumed, I know only two or three. Under these circumstances it is extremely difficult to collect figures which cover the operations for a considerable length of time, and which are so valuable for the metallurgist, who wishes to get an insight into the economy of smelting operations, as shown by practice. Figures obtained by personal observation, which can of course cover only the brief space of the visit of the travelling metallurgist, must, therefore, be made to replace the more valuable data. The writer has had occasion, during the last and the preceding summer, to visit the larger number of the Western lead-smelting works, and offers, in the following pages, such data relating to the economy of lead-smelting in the blast furnace at various works, as he has been able to obtain. The only object in doing so is to place these figures on record, so that they may be from time to time supplemented with other data, which are now wanting. I. EUREKA CONSOLIDATED COMPANY'S SMELTING-WORKS. These works smelt the ores from the mines of the same company on Ruby Hill, Eureka, Nevada. The supply is almost unlimited,

Jan 1, 1873

By J. B. DILWORTA

Ix estimating the investment-value of a mining-property or plant, the value of which decreases with operation, it is often necessary to know the sum which must be set aside periodically from earnings either to renew the plant at the end off its life, or to return the capital involved when the earning-power of the investment has ceased. In such cases it is manifestly incorrect simply to divide the total amount to be retired by the number of periods (usually years) during which the investment shall be active, as the sums periodically withdrawn have a certain interest-earning power varying with the length of time they are held and with the opportunities afforded for their investment. But though the interest may be considered to accumulate regularly year by year, yet the rules and tables for compound interest do not apply, owing to the addition of a fixed amount of new money to the total at the beginning of each period. Briefly stated, the problem of sinking-funds is, to find the amount of money which must be periodically set aside at a certain rate of interest, regularly compounded, to yield a certain sum in a given, length of time. In most practical cases the interest is compounded and the fresh amount added at the same time-usually once a year-and on this basis the problem may be solved as follows

Nov 1, 1909

By H. D. Hoskold

I. Instrument-Parts and Implements. Cross-hairs ; Stadia-measurement; Fineness of Graduation ; Cylindrical Gradu ation ; Nonius; Vernier ; One Vernier or two ; Leveling-Screws ; Troughton & Simms' Shifting Tripod-Head ; Hoskold's Shifting Tripod-Head; Hoskold's Extensible Tripod ; Electric Lamp ; Plumb-lines; Chain. II. Instruments. Compass (Mine-compaes of 1518, Compass of 1541, and Agricolals of 1556, Voig tel's Setz-compass, Circumferentor, Stanley's Hedley Dial, Compass on Tele scope, Hanging Compass, Lack of Precision) ; Plane-table; Octant and Quadrant; Theodolite and Transit (Evolution of the Theodolite, Scott's Tachymeter, Hoskold's Engineer's Theodolite, Angleometer, Precision of Mine-Theodolites). I. Instrument-Parts and Implements. Cross-Hairs.—Mr. Scott‡ says Lean's dial " might also have been provided with a diaphragm and cross-hairs; for Huygene discovered that any object placed in the common focus of the two lenses of a Kepler telescope (1611)- appeared as distinct and well defined as any distant body. Following this established theory, in 1669 Jean Picard, Marquis Malvasia and others crossed silken fibers in the mutual focus of their astronomical instruments." If by this Mr. Scott means that Huygens and Picard first devised and applied cross-hairs to the focus of the telescope, the writer cannot agree with him. Huygens did not describe " his telescope without tubes until 1684, in his Astroscopia Compendiaria."§ Moreover, it is recorded that the English astronomer, Gascoigne,?

Jan 1, 1902

By D. L., Hayes

THE concentration of zinc ore in Wisconsin is a comparatively simple process, although it presents problems that must be overcome in an efficient manner in such a way that installation and operating costs are low. As the ore deposits are small, the first cost of the concentrating plant must be low; while the low margin of profit makes it necessary to have the minimum operating costs. The original mills were copied from those of the Joplin district, as most of them were built and operated by Joplin millmen. These served the purpose well; they made a clean concentrate, which was the chief requirement at that time, as most 'of the mines were' considerably 'richer than the average at the present time, and wages and supplies were also considerably lower. ' The apparatus used at present has changed very little in principle. . The grizzly opening has gradually been increased to 12 in. and sometimes no grizzly 'is used. The crusher, gradually grew in size, the largest crusher has -an opening of about 24 by 13 in. and a 7/8-in. throw on the. eccentric shaft.

Jan 1, 1921

By AIME AIME

A METALLURGICAL research building is to be erected for the Armour Research Foundation at the Illinois Institute of Technology. It will be located at the corner of Federal and 34th Sts., Chicago, and fully equipped will cost $250,000. It will provide the Middle West with the largest and most complete of facilities for the conduct of developmental and industrial research in this field. The new building will be constructed around an existing foundry and metallurgical research building which has become too small to carry on and service the many research projects contracted for by the Foundation, having to do with steel, alloys, and nonferrous metals. After two bays of the new unit have been completed, the old unit will be torn down and the new one completed.

Jan 1, 1942

By A. L. Holley

The first session was held in the rooms of the American Philosophical Society, on Tuesday evening, February 26th. The President, Dr. T. Sterry Hunt, called the meeting to order, and after a few introductory remarks concerning the importance of theoretical and speculative science, which often involves principles of the highest economic value, and, more than all that, serves to enlarge our conceptions of the universe, and ennoble us, by the cultivation which it affords to our most exalted faculties, proceeded to discuss some points in the chemistry of the atmosphere. It is known that there is in the crust of the earth a great amount of oxidized carbon, not only in the shape of coal, but also in the graphite or plunlbago of the crystalline rocks, in the various bituminous shales or pyroschists, which are found in all succeeding rock-formations, and also in the forms of bitumen and petroleum. All the analogies of nature lead us to conclude that these various carbonaceous substances have had an organic origin, and have been generated by the deoxidation of carbonic acid, a process effected by the growing plant, and attended with the liberation of oxygen. He showed that the carbon of a layer of coal covering the whole earth's surface to the thickness of one meter, would, in its production from carbonic dioxide, liberate an amount of oxygen equal to that now present in our atmosphere. But bituminous coal contains also a large amount of hydrogen, derived from the deoxidation of water, which implies the liberation of a farther portion of oxygen. The amount from this latter source would equal, for the various coals and asphalts, from one-eighth to one-fourth, and, for the petroleums, onehalf of that set free in the deoxidation of the carbon which these hydrocarbonaceous bodies contain. From what we know of the composition of the stratified rocks, it is probable that they include an amount of deoxidized carbon and hydrogen many times greater than that contained in a layer of coal one meter in thickness, and, consequently, that the disengaged oxygen in past ages must have far exceeded that now present in our atmosphere. To this must be added

Jan 1, 1879