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By T. E. Schwarz

The Red Mountain district, in Ouray County, Colorado, has been already referred to in the Transactions of the Institute, and notably in papers by Mr. T. B. Comstock, on " The Geology and VeinStructure of Southwestern Colorado" (Trans., xv., 218), and on " Hot-Spring Formations in Red Mountain District, Colorado—A Reply to the Criticisms of Mr. Emmons" (Trans., xvii., 261), and in the paper of Mr. S. F. Emmons, on " Structural Relations of Ore-Deposits" (Tram., xvi., 804). The district has attracted much attention from those interested in geology, because it seems to present a variety of ore-deposits rarely, if ever, met with elsewhere, and one which cannot be described by such well-understood terms as fissure-veins, bedded-deposits, or contact-formation. It will be the scope of this paper to note briefly, from the writer's experience in developing the Yankee Girl, Guston and other Red Mountain properties,—first, observed facts as to the ore occurrence and formation, and second, certain unsolved geological questions. The Red Mountain district proper occupies the headwaters of Red creek, from Iron ton to the Divide, a distance of 5 miles. Its leading properties occur on the west slope of Red Mountain. The mode

Jan 1, 1890

By W. F. Laverty

Two recent papers in this journal1,2 contain experimental evidence for an anomaly in the concentration gradient for tracer diffusion. In both papers, the authors suggest that this anomaly is due to a Gibbs' absorption effect. Their hypothesis is that surface active tracer elements tend to remain in or near the surface adsorption layer, thereby altering the diffusion flux and concentration gradient. It is not clear how the anomaly can be explained in terms of an adsorption effect. Surface tension forces act parallel rather than perpendicular to a surface and therefore should affect only the rate of spreading of surface active agents tangentially across a surface. Frenkel3 has given a short treatment of surface tension as a driving force for surface diffusion. While the equilibrium concentration of a surface active agent at the surface of a solution is known to be higher than in the bulk, its chemical potential is necessarily the same. It is difficult to see how adsorption can result in an anomaly in the chemical potential gradient, which is the driving force for diffusion. A more detailed explanation by the authors of the adsorption mechanism is in order. A similar anomaly does not seem to arise where

Jan 1, 1970

By D. L. King

The San Francisco Chemical Co. has been actively interested in phosphate mining since 1908. It was, in fact, the first company to make claims on properties in the western phosphate belt. From the period of 1908 to 1947, the company's phosphate operations were centered at their Waterloo property, five miles east of Montpelier, Idaho. A small tonnage of phosphate rock was shipped annually from their underground mines in that area. In 1945, the company started the first western open-pit phosphate mine on the slopes of Waterloo Hill. In 1947, they obtained an option and lease on the Beckwith Hills' deposits in southwestern Wyoming, some 25 miles south of Cokeville. While the operations at Montpelier and the Beckwith Hills are both open pit, there are many differences which suggest separate treatment in this paper. Structurally, the Waterloo Hill is the west slope of an anticline. The beddings dip from 20" to 35" to the west. Erosion has caused the footwall exposures (Well's formation) to appear in the upper areas as a series of apices, giving the outcrops a festooned arrangement. Dip faulting with subsequent erosion has induced gullies normal to the strike and resulted in eroded areas which separate the remnants of the

Jan 1, 1950

By Eric Jette

THE alloys of gold and iron were investigated in 1907 by Isaac and Tammann,1 who determined the thermal diagram for the entire system by thermal analysis and microscopic examination. They also reviewed the previous literature. Since that time the present authors have been able to find only two additional references. Guertler and Schulze2 examined the electrical resistance of iron alloys containing up to 40 per cent by weight of gold between 0° and 200° C.; the alloys were in the form of wires. The main result of this work was to confirm the solid solubility limit found by Isaac and Tammann; namely, about 20 per cent Au. More recently, Shih3 has examined the magnetic properties of gold alloys containing up to 10 weight per cent iron and particularly the range below 5 per cent. The alloys in the lower range were found to be paramagnetic; the 10 per cent alloy was ferromagnetic. The present investigation was undertaken to determine the solid solubility limits at various temperatures, particularly below the a-y transformation point of iron, since these solubilities are of some impor-tance in connection with the working of the alloys in the manufacture of certain "grey" and "blue" golds.

Jan 1, 1934

By William Kelly

An extensive swamp covers a large part of the town-site of Norway and adjacent laud. Through this swamp run two parallel oreformations. In the north one is the Aragon mine. The south one passes into the swamp on the Harrison property. On the edge of the swamp, about 1000 feet from the Aragon mine, a diamond drill, in the fall of 1889, located the ore-bearing formation and a probable ore-body. To explore further and develop this ore, the Penn Iron Mining Company proposed, in the spring of 1890, to sink a shaft. The drill had shown the depth of the glacial drift to be more than 60 feet. A test-pit near the location of the proposed shaft had struck, at a depth of 20 feet, an amount of water which a 200gallon pump was unable to lower. At the Aragon, a few years before, a shaft had been sunk to hard pan with great difficulty and many delays by the usual method of driving laths. Under the conditions it was decided to sink a caisson- or dropshaft. Two 40-horse-power boilers, a Lidgerwood engine with 4foot drum, and a good derrick were set up; and two No. 10 Kuowles

Jan 1, 1892

By Howard M. Graff, Sidney C. Bouwer

The economics of mining has traditionally been viewed quite apart from the economics of blast furnace operations. It was realized, of course, that blast furnaces would operate best with good raw materials, but the shipping grade of ore, for example, was decided by a sort of collective bargaining process between the ore producers and the blast furnace operators. The mine operators had to keep their costs down, and were usually successful in convincing management that the ore in any particular deposit was endowed by nature with a certain iron content and that the mine grade could not be raised beyond a certain economic limit. The blast furnace operators would have liked a better grade, but as long as they were able to make a fairly good showing it was more or less accepted that they had to take the ore as it came. The mine operators were able to ship to the nation's blast furnaces thousands of tons of iron ore that would be completely unacceptable by present-day standards. As late as the early 1950's, the major steel companies were witnessing an actual decline in the iron content of their incoming ore supply as the mining companies mined progressively leaner material and upgraded it only enough to pass competitive market requirements

Jan 8, 1965

By William Hamilton Merritt

A brief paper on this subject (which might readily be made to, fill a volume) is suggested at this time by several considerations, among which may he named the meeting of the Institute on the borders of Ontario, not far from some of the mining undertakings which are hereafter mentioned ; the mineral developments made in the Province quite recently ; the highly creditable collection of most of the minerals of Ontario, for the first time got together, and exhibited this year at Cincinnati, in the Centennial Exhibition of the Ohio Valley ; and, finally, the recent appointment, by the Government of Ontario, of a Commiesion to inquire into, and report upon the mineral resources of the Province, and the best means to be adopted for their development. The Province of Ontario has no Department of Mines or official geologist, to take note, and keep record, of mining and mineralogical development and discovery. Within the last few years some valuable statistics have been collected by Mr. A. Blue, the Deputy Minister of Agriculture; but recently a desire has risen on the part of the people to obtain further knowledge of these subjects, and the government has appointed a Commission, the report of which is expected to be issued in part, if not in completed form, this winter.

Jan 1, 1889

By C. Jackson, J. J. Harrington

The pH control system at Kennecott Copper Corporation's Nevada Mines Division concentrator consists of two independent systems, lime dilution and lime addition. Lime dilution is accomplished in a mixing tank where slaked lime and water are introduced proportionately. The desired dilution of the milk of lime is determined by the electrical inputs provided by eight pH probes, one per grinding section. The inputs are averaged and applied to a time base generator. The summation output of the time base generator determines the proportion of lime and water that are to be mixed and applies this input to a voltage sensitive switching device. The switching device provides a signal to one of two relays which will add either slaked lime or water, dependent upon the summation output. The entire cycle is based on a 2-min repetition rate to allow for sufficient mix time. Responsivity is controlled by maintaing a limited maximum solution level in the mix tank. Lime addition is controlled independently within each grinding section. The electrical input from the pH probe in a given section controls the solenoid valves which provide lime to each of the ball mills. The valves remain open within a time range capable of maintaining the pH of flotation feed at a given set point.

Jan 1, 1978

By R. V. Ramani, George W. Luxbacher

Computer simulation of mine ventilation systems, after a slow start in the early sixties, is gaining increasing acceptance for planning, design, and evaluation purposes. Numerous programs are readily available from government, university, consulting, and industry sources. The computer adage "garbage in, garbage out" is as applicable in ventilation engineering as in any other application of computers, and has been responsible for the questionable results obtained in some instances. The source of input data for a ventilation simulation is most often a pressure-quantity survey of the mine, or, in the case of a new mine, information derived from a survey of an existing mine which has conditions similar to those expected in the new mine. The crucial step is to generate simulation input data from the ventilation survey. Problems such as quantities that do not balance, pressure gradients opposite to measured air flow, differences in the pressure datum in a multi-shaft mine, modeling of leakage, and deviations in flow from the square law (H=RQ2) are frequently encountered and must be resolved. The purpose of this paper is to discuss these aspects and to propose procedures which can lead to input data for valid simulations of mine ventilation systems.

Jan 1, 1982

By L. D. Godshall

The latest revised edition of Mr. C. A. stetefeldt's book on the Lixiviation of Silver-Ores, which appeared very recently, contains no mention of the volatilization of silver in chloridizing-roasting—an omission which is the more remarkable in view of the fact that in former editions of the work this important subject was noticed. Moreover, Mr. Stetefeldt has discussed it to some extent in his paper on " The Stetefeldt Furnace," * in which he criticised certain statements made by me before the Colorado Scientific Society in May, 1893, in a paper entitled " A Review of the Russell Process;" ? and Mr. Morse, in his paper on " The Lixiviation of Silver-Ores by the Russell Process at Aspen, Colorado," $ has given statistics showing the loss of silver by volatilization (including the dustloss, which Mr. Morse estimates at not more than 1 per cent.) on more than 30,000 tons of ore roasted, to have been 9.16 per cent. The matter must certainly be deemed important enough to warrant me in returning to it, and offering, with the aid of the figures made public since my first paper, a reply to the criticisms of Mr. Stetefeldt. The passages of my paper which he deemed to be " ques-

Jan 1, 1897

By John Chipman, Donald W. Murphy

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

Jan 1, 1935

By J. H. Swisher

Two recent papers in this journal1,2 contain experimental evidence for an anomaly in the concentration gradient for tracer diffusion. In both papers, the authors suggest that this anomaly is due to a Gibbs' absorption effect. Their hypothesis is that surface active tracer elements tend to remain in or near the surface adsorption layer, thereby altering the diffusion flux and concentration gradient. It is not clear how the anomaly can be explained in terms of an adsorption effect. Surface tension forces act parallel rather than perpendicular to a surface and therefore should affect only the rate of spreading of surface active agents tangentially across a surface. Frenkel3 has given a short treatment of surface tension as a driving force for surface diffusion. While the equilibrium concentration of a surface active agent at the surface of a solution is known to be higher than in the bulk, its chemical potential is necessarily the same. It is difficult to see how adsorption can result in an anomaly in the chemical potential gradient, which is the driving force for diffusion. A more detailed explanation by the authors of the adsorption mechanism is in order. A similar anomaly does not seem to arise where

Jan 1, 1970

By Donald W. Murphy, John Chipman

Recent developments in iron alloys containing nitrogen have indicated that this element may exert a considerable influence on the properties of the metal. This influence is not always in an undesirable direction and the indications are that nitrogen should be regarded as an alloying element, the amount of which should be subject to control, rather than as an inherently deleterious impurity. In controlling this element in liquid iron to the best advantage, it is necessary to have a reliable background of fundamental data pertaining to solubilities, rates of solution and chemical reactions of nitrogen in liquid iron. Obviously, the first step in such an investigation is the determination of the solubility of nitrogen in pure iron, and this has been the object of the experiments described in this paper. The solubility of nitrogen in solid iron has been measured by Jurich,' Sieverts,2 Martin,3 and Iwasé4 and the agreement among the first three inspires confidence in their results. No accurate determinations of its solubility in liquid iron have been recorded though several investigators have obtained approximate results. Strauss6 was able to introduce 0.03 to 0.04 per cent nitrogen into steel by the action of either ammonia or nitrogen on the liquid metal. This was accomplished by Eilender and

Jan 1, 1935

By John Chipman, Donald W. Murphy

Recent developments in iron alloys containing nitrogen have indicated that this element may exert a considerable influence on the properties of the metal. This influence is not always in an undesirable direction and the indications are that nitrogen should be regarded as an alloying element, the amount of which should be subject to control, rather than as an inherently deleterious impurity. In controlling this element in liquid iron to the best advantage, it is necessary to have a reliable background of fundamental data pertaining to solubilities, rates of solution and chemical reactions of nitrogen in liquid iron. Obviously, the first step in such an investigation is the determination of the solubility of nitrogen in pure iron, and this has been the object of the experiments described in this paper. The solubility of nitrogen in solid iron has been measured by Jurich,' Sieverts,2 Martin,3 and Iwasé4 and the agreement among the first three inspires confidence in their results. No accurate determinations of its solubility in liquid iron have been recorded though several investigators have obtained approximate results. Strauss6 was able to introduce 0.03 to 0.04 per cent nitrogen into steel by the action of either ammonia or nitrogen on the liquid metal. This was accomplished by Eilender and

Jan 1, 1935

By Alvin H. Lense

In the spring of 1967, after a careful study of existing geology along the Pacific Coast including Alaska, the USBM, in conjunction with the USGS, decided that the offshore area around Nome, Alaska, presented an unparalleled land-to-sea comparison site for the evaluation of marine core drilling techniques and sampling equipment. Considering the geological evidence available and the production history of the Nome Beaches (5-6 million oz. of gold recovered), it appeared likely that gold in commercial quantities could occur in the offshore area. A 180 sq mi area of Norton Sound, extending roughly 14 miles to the east and west of Nome and averaging 6 miles to the south, was tested by approximately 530 line-miles of sub-bottom profiling. A total of 4043 ft (56 holes) were drilled in unconsolidated sediments, yielding mixtures of gravel, sand, silt and clay. Of the total holes drilled, 16 went to bedrock and six were terminated short of their intended depths due to boulders which halted penetration, or rough seas which caused the ship to move as the anchors slipped over hard sea-floor surface. The rest of the holes were terminated when the penetrative capabilities of the drills were reached, or when the required amount of geological data were attained.

Jan 8, 1968

By Paul R. Wieber, Atam P. Sikri

This paper describes the U. S. Energy Research and Development Administration's (ERDA) program to develop in situ coal conversion processes, especially gasification. The potential of this technology, the technical directions being explored, and the program strategy to carry the process concepts toward commercialization are emphasized. The geographic location of the U. S. coal resources and a market analysis are described. Commercially successful in situ coal processes could add over a trillion tons of coal to the U. S. coal reserves. The economics of these processes is compared with surface gasification. Independent studies show this process to be 25% cheaper than surface gasification for Western coals. The major projects are briefly described. The Linked Vertical Well process is in the most advanced stage and shows great promise. The last test produced a low-Btu gas averaging 171 Btu per standard cubic foot for average production rates of 8.5 million standard cubic feet per day. The other projects are Packed Bed, Longwall Generator, and Steeply Dipping Beds. Unique factors of the process development are discussed which may lead to commercial processes in the near term. A development strategy is proposed by which this technology could be commercialized before 1983 with potentially lower gas prices and lower environmental impacts, relative to mining plus surface gasification.

Jan 1, 1979

By Paul R. Wieber, Atam P. Sikri

This paper describes the U. S. Energy Research and Development Administration's (ERDA) program to develop in situ coal conversion processes, especially gasification. The potential of this technology, the technical directions being explored, and the program strategy to carry the process concepts toward commercialization are emphasized. The geographic location of the U. S. coal resources and a market analysis are described. Commercially successful in situ coal processes could add over a trillion tons of coal to the U. S. coal reserves. The economics of these processes is compared with surface gasification. Independent studies show this process to be 25% cheaper than surface gasification for Western coals. The major projects are briefly described. The Linked Vertical Well process is in the most advanced stage and shows great promise. The last test produced a low-Btu gas averaging 171 Btu per standard cubic foot for average production rates of 8.5 million standard cubic feet per day. The other projects are Packed Bed, Longwall Generator, and Steeply Dipping Beds. Unique factors of the process development are discussed which may lead to commercial processes in the near term. A development strategy is proposed by which this technology could be commercialized before 1985 with potentially lower gas prices and lower environmental impacts, relative to mining plus surface gasification.

Jan 5, 1978

By B. Amero, W. Petruk, D. R. Owens, D. R. Morris

Samples taken at different heights in the lead blast furnace of Brunswick Mining and Smelting corporation were studied to determine the phases present in order to interpret the reactions In the furnace. The main phases in the blast furnace feed are Pb3Ca2S13011, Zn ferrite (ZnFe204), and hardystonite (Ca2ZnSi207); rninor ones include lead and a Pb silicate. The temperature in the furnace varies from about 300°C at 4.2 m above the tuyeres to 1150°C at 1.1 m. There is no evidence of reactions in samples from points cooler than 800°C. Some reaction occurs between 950° and llOO°C and the lead sinter is nearly decomposed at about 1150°C. The first evidence of reaction was the decomposition of Pb silicate to lead and S102. At higher temperatures the Pb Ca2Si3011 decomposed to form lead and hardystonite (Ca2ZnS120rf. The Zn required for hardystonite was derived from the Zn ferrite which apparently re-equilibrated to a new Zn ferrite with less Zn. The decomposed sinter consists essentially of lead, hardystonite, wustite and a Zn ferrite with a low Zn content.

Jan 1, 1984

By W. W. Harvey, F. O. Dudas

Toward hot hydrochloric acid, the usual order of reactivities of the common copper sulfide and associated minerals is reversed, and the rates of H2S formation vary as [ ]. The iron component of chalcopyrite and bornite reports to the solution as ferrous chloride, while pyrite remains essentially unreacted. If a pressure of H2S is maintained in the reactor, copper solubilization is suppressed, and the primary copper sulfides are converted to finely divided secondary sulfides (principally covellite). The HCl leach reside then consists mainly of covellite, pyrite and acid-insoluble gangue. Copper can be selectively leached from this upgraded concentrate to yield a clean, strong copper sulfate solution for direct electrowinning. Preliminary analysis indicates competitive economics with respect to established hydrometallurgical processes. Other concentrate treatments based on an initial HC1 leach are proposed and relative advantages compared. The common denominator of the major process routes considered is the requirement to regenerate HC1 from an FeC12 solution. Five distinct concentrate compositions were employed in the experimental study, which included some attention to the fates of selected minor constituents of the copper concentrate, especially gold, silver, molybdenum, arsenic and selenium. Significant mineralogical features of reactants and products are described.

Jan 1, 1978

By A. B. Parsons

Not so many years ago the interest of the average mining engineer in money matters-aside from his pay check or his consulting fees-was confined to the per-ton cost of mining and beneficiating ore and to the amount of capital that would be required to erect the plant necessary to carry out such operations on a prescribed scale. The so-called "business men" assumed that questions of marketing the products, of profits, and of dividends were in their exclusive sphere-matters too intricate or, perhaps, too practical for the mere engineer! In the case of a new enterprise, the promoter shouldered the entire responsibility for raising the necessary funds, and incidentally he got the lion's share of profits. In fact, he frequently profited handsomely even though the mine earned little or nothing. Occasionally the engineer turned promoter or entrepreneur--conspicuous examples are Herbert Hoover, D. C. Jackling, William Braden and F. W. Bradley- but by and large he remained in a sphere of his own. To what extent this condition of affairs has changed is difficult to say. It might be argued that it were better that it be not changed; and yet I cannot help feeling that in mine promotion lies a distinct opportunity for the

Jan 1, 1932