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By R. D. Rosenkranz

The Bureau of Mines has investigated the availability of copper from 272 deposits in market economy countries. The deposits studied have demonstrated resources totaling 413 million metric tons of contained copper and account for more than 90 pct of the reserve base for market economy countries. Using data gathered as part of its Minerals Availability Program, the Bureau performed geologic, engineering, and economic evaluations in order to determine the copper production potential of each deposit. At the 1981 copper market price of $0.85/lb, the deposits studied could economically produce an estimated 88 million metric tons of copper (allowing for profit computed at a 15-pct rate of return), primarily from mines operating at the time of the study (1981). At this price, producing mines in market economy countries could economically produce only 2.1 million metric tons of refined copper per year. However, actual 1981 production was 6.2 million metric tons, indicating that many mines continued to operate even though they were unable to cover all production costs. For U.S. producing mines, the estimated average cost of production per pound (including profit at a 15-pct rate of return) was $0.15 higher than the average cost in other market economy countries.

Jan 1, 1983

By L. W. Scott

This report presents an overview of explosionproof (X-P) enclosure research being conducted by the Bureau of Mines, This report emphasizes the increasing importance of research related to the safety con- siderations of X-P enclosures used in underground coal mines. Selected topics are included that summarize results of research in the areas of electrical clearances, reliability of enclosures with windows, safety factors in X-P enclosures, potting materials, performance tests for X-P enclosures, protection against high-voltage explosions, and innovative X-P devices.

Jan 1, 1985

By John W. Buch

Hydraulic cutting tests made on samples of Pennsylvania anthracite (3,700 psi and 260 gpm) were promising enough for the Bureau to establish a full scale experiment in an anthracite mine. Water pressure and quantity for mining anthracite were arbitrarily established at 5,000 psi and 300 gpm (1,000 hp). For full-volume flow, hydraulic pressure is controlled by orifice size with the displacement pump. The hydraulic jumbo was designed for maneuvering on pitches from 0° to 20° in any direction and for a coalbed ranging in thickness from 10 feet 6 inches to 15 feet. All motions of the jumbo are by oil hydraulics. Jet flow is controlled (start-stop) at the face, through an interlocked pushbutton system. One button is in the operator's cab; one, at the pump station; and one (a safety shutoff), near the mining face. To December 1962, 7,400 tons of bed material had been mined at an average rate of 0.800 ton per minute, with an average power requirement of 14.125 kilowatt-hours per ton. In January 1963, the objective was changed from an engineering-development basis to a research basis--to determine, ultimately, the most efficient level of operating characteristics for maximum response, as measured by mining-out rate. This research phase of the project is not yet complete, but conclusions, and the method of arriving at them, will be made the subject of another Bureau publication. It should be noted that as of December 1963 nearly 13,000 tons of bed material had been mined, at rates as high as 1. 3 tons per minute for a complete face advance.

Jan 1, 1965

By M W. A Asad, E Topal, D S. S Sandanayake

Underground mine planning requires an optimal stope layout as a prerequisite for the definition of an optimal production schedule. The procedure to generate an optimal stope layout considers an orebody model and economic parameters as inputs. It evaluates all possible combinations of mining blocks and creates a set of stopes by satisfying the physical mining and geotechnical constraints. Thus, the procedure is computationally complex, and generating a solution to the problem is a challenge. This paper presents an implementation of a new heuristic algorithm that solves the stope layout problem. In two case studies, the algorithm achieves 11.2 per cent and 22.5 per cent superior solutions to the industrially available maximum value neighbourhood approach.CITATION:Sandanayake, D S S, Topal, E and Asad, M W A, 2014. Implementing a new heuristic approach to the underground mine stope layout problem, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 243–248 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By J. Winters, L. Vos, C. Canoo

Committed to a sustainable development of zinc applications, Union Miniere is investigating processes for the minimisation of waste and residues originating from the classic hydrometallurgical zinc process. In that context, Union Miniere has developed a method for the cold inertisation and solidification of goethite, the Graveliet® process. The result is a hard and inert gravel that can be used in the building industry. During the past two years, a pilot plant for the production of Graveliet® has been built and operated. In the present paper, the Graveliet® process and the pilot plant are described after which the properties of the produced gravel are discussed, from both a mechanical and an environmental point-of-view. Graveliet fulfils the criteria for use as a secondary building material. The GravelietJ process is a viable technology to avoid stockpiling of goethite residues and it thus assures the long-term development of the hydrometallurgical zinc process.

Jan 1, 2000

By C. H. Li, R. J. Stokes, T. L. Johnson

The effect of alumina particles on the nucleation and growth of cracks through a silver- chloride matrzx has been investigated. It has been found possible to promote fibrous cracking in dispersion-strengthened silver, chloride under notch-impact conditions at temperatures at which silver chloride alone cleaves brittlely The modification) of fracture beIzavzor is thought to be due to the relaxation of hydrostatrc stress beneath a notch by the nucleation of cavities near alumina particles. In recent years, composite or dispersion-strengthened materials have been studied primarily to understand their high resistance to plastic flow particularly at elevated temperatures. Dislocation models have been developed with which it is possible to deduce with fair success the effects of interparticle distance, particle size, temperature, upon yielding and creep behavior.l-4 Much less attention has been paid to the fracture behavior of these materials (with the notable exception of common structural steels) and little is known experimentally about the manner in which inclusions affect the nucleation and growth of cracks through a matrix. Nevertheless a beginning has been made in connection with fibrous cracking in ductile matrices where inclusions appear to play an essential ro1e.5-7 During the severe localized plastic deformation which accompanies necking in a tensile test, cavities are believed to develop at inclusions; these cavities subsequently grow and coalesce by plastic flow until separation is complete. It is of interest to consider whether inclusions can affect fracture behavior under loading conditions which restrict the plasticity of the matrix itself (for example, cleavage under conditions of a high imposed strain rate at low temperatures). It is particularly interesting to study these effects in a solid which shows a spectrum of behavior ranging from fully ductile to semi-brittle behavior. Such a solid is silver chloride whose mechanical behavior depends sensitively upon temperature and strain rate.'," The present paper is concerned with a study of the influence of inclusions (in the form of alumina particles) on the fracture behavior of silver chloride loaded uniaxially at low strain rates at room temper- ature and also under notch impact conditions over a wide range of temperature. In particular, it will be shown that the alumina particles can exert a startling effect on the ductile-brittle transition temperature of notched silver chloride and that the magnitude and nature of the effect depends upon both the quantity of alumina and the shape of the alumina particles. 1. EXPERIMENTAL PROCEDURE 1.1 Materials Used. Silver chloride powder of analytical reagent (AR) quality having an average particle size 6 was supplied by the Mallinckrodt Chemical Works (st. Louis, MO.). Acid washed 900 mesh alumina powder, designated A38-900, was supplied by the Norton Co. (Cambridge, Mass.). This powder was added to silver chloride in two forms: a) the as-received condition in which the individual particles were of random irregular shape; their statistical average size was 7; b) in a condition in which each particle was spherically shaped by a fusion technique. In this case, the statistical average particle size determined with the optical microscope was approximately the same (about 5p) but electron micrographic evidence indicated that many ultra fine particles were present in the spheroidized powder. 1.2 Preparation of Composite Materials. Silver chloride-alumina composites containing 2.5, 5, and 15 pct by volume of alumina were produced by the extrusion of mechanically mixed powders blended in a ball mill for 24 hr at room temperature. The mixtures were compacted at 50,000 psi at room temperature in the form of billets 3/4 in. in diameter and 1 in. long which were then extruded with a 16:l reduction ratio at 370°C through a radius-type steel die having a 5 deg lead-in angle. An extrusion temperature of 370°C was selected to ensure that all composites had sufficient plasticity to be extruded. Apart from this general requirement, the choice was arbitrary. 1.3 Microstructure of Composites. Attempts were made to check the distribution of alumina metallo-graphically by polishing transverse and longitudinal sections of the extruded rod. Specimens were wet-ground to 600 emery paper and lapped successively with 5 and 0.25-p grades of diamond paste. They were etched for 10 sec in 10 pct sodium thiosulfate solution and lightly polished in concentrated ammonium hydroxide. The most effective way to render the alumina particles and grain boundaries visible was to radiate the surface with intense white light to decorate the grain boundaries and the particle-matrix interfaces photolytically.

Jan 1, 1962

By M. Redfearn

"DUST COLLECTION EQUIPMENT LIST Primary Dust CollectorModular Mikro-Pulsaire - Model 2G1-96TR Capacity: 20,000 c.f.m.Bags: Total of 288; 8' x 4 1/2"" diameterMaterial: Dacron HCE feltAir to cloth ratio: 7.55/1Bags are changed every 6-9 months. Sent to A & L Services for cleaning at a cost of less than 1/3 the price of a new bag. No new bags have been required since start-up 4 years ago.Blow hack: 35 c.f.m. at 100 p.s.i.Fan: Joy Manufacturing, Model 3300, Type 4S, Backward inclined fan.Impeller: 33"" diameter36"" diameter Inlet33"" diameter Outlet at 3200 f.p.m. velocity1945Motor:,60 H.P., 1780 r.p.m.Capacity: 23,400 c.f.m.Design:,20,000 c.f.m.,•Actual:,17,500-19,000 c.f.m. depending on bag condition.Dust Slurry Agitator: Port-a-flo Model 050-350Major Maintenance:The fan was sped up from 1830 to 1945 r.p.m. and balanced at the higher speed. Several months later the impeller destructed beyond repair. A new shaft and impeller was installed, casings straightened, and bearings reused. Unit is currently running at 1945 r.p.m. No definite cause for the impeller failure has been found, although it might be attributed to improper balancing."

Jan 1, 1976

By Alain Simard, Sylvain Lacroix, Louis-Martin Dubé, Pierre Pilote

"The Harricana-Turgeon belt (HTB) is a poorly known volcano sedimentary belt in the NW part of the Abitibi Sub-province; it includes the Matagami, Joutel, Brouillan and Casa-Berardi mining districts. The HTB is dominated by volcanic rocks, which covers 65% of its surface area, followed by sedimentary (18%) and plutonic (17%) rocks. It is also transected by numerous deformation zones located either at the contacts of volcano-sedimentary units and granitoid bodies or cross-cutting them. A preliminary geological synthesis shows that mineral deposits are associated with certain regional geologic elements.The volcano-sedimentary units are grouped here into twelve band-shaped lithotectonic domains, most of which extend for more than 150 km E-Win the HTB. Each domain is defined by lithologies and facies associations, and gradiometric and electromagnetic signatures.Eight domains are composed of basaltic or basaltic to komatiitic associations, interlayered with thin pelagic sediments, representing sub-marine lava plains. Two domains are composed of basaltic to rhyolitic associations that are interpreted as volcanic arcs formed by one or several central volcanic complexes.The sedimentary rocks are grouped into two lithotectonic domains. Each is composed of rhythmic sequences of turbiditic sandstone- siltstone-shale, Algoma-type banded iron formations and conglomerates bearing plutonic and volcanic pebbles. These three facies come partly from mass flow at the bottom of a slope in a moderately deep marine environment. In each domain, a conglomerate sandstone- siltstone sequence, containing poly genetic pebbles of local provenance, is similar to Timiskaming-type alluvial deposits.The nineteen granitoids, found within the HTB and at its border, belong to numerous petrographic suites, and have been grouped into four structural families: pre-tectonic, pre- to early-tectonic, syn- to late-tectonic, and late- to post- tectonic. The pre- to early-tectonic plutons are presumed to be sub-volcanic and are generaly associated with the volcanism of central complexes.The HTB mineral resources consist essentially of polymetallic (Cu-Zn-Ag-Au) and gold (Au-Ag) deposits. The polymetallic deposits are located exclusively in the two lithotectonic domains composed of basaltic to rhyolitic associations (Matagami-Brouillan and Joutel Raymond). All gold deposits are associated with deformation zones superimposed on lithotectonic domain contacts and highlighted by graphitic units. Most of the deposits are hosted in the Casa-Berardi and Douay deformationzones, located at the contact of the Cartwright basaltic to komatiitic domain and the Taibi sedimentary domain"

Jan 1, 1990

By Terrence M. Carroll, Chu E. Ho, Dimitrios Niarchos

"Construction of the new extension to Terminal 4 at John F Kennedy International Airport in Queens, New York involved the application of tapered piles for foundation support. Initial design based on past load testing experience had indicated that a pile depth of 65 feet was necessary to achieve a capacity of 394 tons. However, piles with a single length of 62 feet were ordered and installed, which led to marginal performance of the piles. This paper presents the technical considerations for mitigating the situation based on a systematic review of three preliminary pile load tests and dynamic capacity measurements on the shorter piles. Consideration was given to the long term gain in capacity of tapered piles due to set up in the Glacial Sand. The observational approach to the evaluation of piling performance adopted on this project resulted in salvaging many piles which failed to comply with the specified driving criteria. It was acknowledged that a more prudent course of action was for the Contractor to have ordered more appropriate pile lengths that allowed for potential variation in soil conditions across the site. The 4.6% saving in pile material did not warrant the effort that was required to mitigate the 39% of installed piles that did not meet the specified driving criterion.INTRODUCTIONAn expansion project at John F. Kennedy International Airport in Queens, New York involved the Phase 2 extension of Concourse B at Terminal 4. The site consists of 4 to 5 feet of pavement over about 10 feet of hydraulically placed sandy fill. Below this is a layer of marsh deposit, comprising of soft organic clay and peat, up to about 11 feet thick. Beneath the marsh deposits is a deep layer of glacial sand which extends to well over 100 feet below ground. Figure 1 shows the typical subsurface profile at the site. The new structures were supported on 223 steel tapered piles. The piles consisted of a straight steel pipe 18 inches in diameter and 0.375 inches thick, with a 25 feet long tapered bottom section (diameter varying from 18 inches down to 8 inches at the pile toe). The piles were first driven to the founding depth and subsequently in-filled with concrete. The concrete strength (fc) specified was 4,500 psi and the yield strength of the steel piles (fy) was 50 ksi. Initial pile design, based on earlier experience with static pile load testing for Phase 1 development at the same terminal, indicated that a pile length of 65 feet was necessary. However, piles with a single length of 62 feet were ordered and installed by the Contractor, leading to marginal performance of the piles. This paper presents the technical considerations for the adoption of alternative pile driving criteria, based on a systematic review of the preliminary static load test results for the present site and PDA measurements obtained during pile installation, in order to accommodate the capacity of the shorter piles."

Jan 1, 2017

By Erik Westman, BEN WESTON, SETAREH GHAYCHI AFROUZ, KATHRYN DEHN

One of the most difficult challenges in underground mining is to forecast significant seismic events prior to their occurrence in order to support the safety of miners and to minimize damage to the underground operation. Passive seismic tomography is a tool to image the seismic velocity changes in a rockmass, which can potentially reveal the rockmass behavior before and after a significant seismic event. In this paper, the changes in seismic velocity of the rockmass before and after three major seismic events are investigated to determine whether there are identifiable precursory velocity changes associated with the major seismic events. Conventional mechanics imply that the induced stress at the hypocenter would continue increasing until failure, in the form of an induced seismic event, occurs. With passive seismic tomography we can image changes to the seismic wave velocity distribution within a rockmass and hence infer the changes to the induced stress near the hypocenter. This paper evaluates the hypothesis that induced stress at the hypocenter (as inferred by the p-wave velocity) increases until the seismic event occurs. In addition to analyzing p-wave velocity changes near the hypocenter, changes to the p-wave velocity at “zone centers” were also analyzed. These “zone centers” are regions within the rockmass that consistently have a p-wave velocity that is much higher than the average p-wave velocity for the rockmass. It is found that the p-wave velocity did not increase at any of the three hypocenters prior to the seismic event occurring, however the p-wave velocity did increase in the closest “zone center” for two of the three events.

Oct 12, 2020

By D. Renda

With thise Process of obtaining a solid fuel which is both ecological clean and has a high calorific value by a two-stage method of enriching preferably type lignitic coals to remove a high content of all sulphurs, incuding organic sulphur, which method comprises converting the coal to a semi-coke from followed by magnetic separation. In the Experiments given the best results the washed lignite coal in the West-Turkey, Tavsanli- Region, size -3.35 mm on dry basis. In the microscopic studies of the brigh-thin cross-section taken from the samples of sulfur min-erals pyrite in the dimension of 2~50 micrometers and melnicovite 10 micrometers particles. An thermal treatment an semi-coking themperature between 370°C to 650°C give the best Result of 480 °C. The oxidation and decomposition of sulphur minerals pyrite and melnicovite in lignite coal proceed the iron oxides Fe2O3 and pyrrhotite FeS on the surface layer. The Magnetic Seperator (Rare Earth Magnetic Separator, REMS) is capable this two form of sulphur, including organic and inorganic sulphur, in semi-coke and resulted in the magnetic-fraction in REMS. The non-magnetic-fraction remove total sulphur by 68 %, ash by 44 % and increase the upper calorific value in 15 %. The clean lignitic coal can be utilized in human or energy power stations.

Jan 1, 2014

By Jorma Miettunen, Reijo Kalapudas, Pertti Koivistoinen

A new method for measuring the mill filling was developed by Outokumpu’s Pyhäsalmi concentrator during 1989-90. The method utilizes the power draw oscillation which is caused by the mill lifters. Each lifter bar causes a peak in the power draw and thus a continuous oscillation results. In a fixed time scale, the oscillation peaks will shift as the lifter bare hit the mill charge sooner or later depending on the volumetric filling of the mill. Thus the measuring method is based on the phase shift of the power oscillation. So far the measurement is utilized for maximizing throughput of the primary mills at Pyhäsalmi and Enonkoski concentrators and at Harjavalta slag concentrator. The paper describes the new method and the results achieved.

Jan 1, 1992

By John J. Mulligan

The creeks draining Cape Mountain, on the western tip of Seward Peninsula, Alaska, comprise the Cape Mountain tin-placer district. Because of the war-caused shortage of tin, the Bureau of Mines in 1943 conducted a churn-drill placer reconnaissance to explore the district. Favorable indications were found, and plans were made for further investigation of the deposits; the plans were abandoned when tin again became plentiful. In July 1951 the Zenda Gold Mining Co. was granted a Defense Minerals Administration (Defense Minerals Exploration Administration after October 1951) loan to continue exploration of the more favorable areas indicated by results of the Bureau's investigation. Equipment was moved to the area in the fall and winter of 1951-52. During the 1952 field season, 209 churn-drill holes totaling 7,521 linear feet and 10 test shafts totaling 96 linear feet were sunk on the Cape Creek drainage. Work was resumed in 1953, when 56 churn-drill holes totaling 3,157 linear feet were drilled on Boulder Creek. The company planned to drill Goodwin Gulch and Goodwin Creek, but no further work was done owing to lack of capital.

Jan 1, 1959

By A. A. Cochran

Bureau of MinesThe Bureau of Mines studied the development of practical methods for recovering manganese from the extensive domestic resources of low-grade ores and open hearth slags. A one-step operation was developed on a laboratory scale in which manganese and iron compounds are treated with chlorine, volatilized, and separated by selective condensation. Manganese recoveries of 90 to nearly 100 percent were obtained from 9 of the most important domestic ores. Analyses of the manganese chloride product indicated that it was suit-able for aqueous electrolysis with little additional purification. A complete, integrated process that provides for the recovery and recycling of chlorine is proposed. This process appears to have distinct advantages over previously proposed manganese recovery processes, and, in sharp contrast to leaching procedures, it is applicable to practically any manganese-bearing material.

Jan 1, 1967

By H. L. Martin

A joint federal-provincial approach in gathering basic information from industry on mine production, concentrator operations and ore reserves, initiated during 1978, is a major step toward the goal of achieving better government-industry communication through a common data base. Information from questionnaires sent out by provincial governments is shared with the federal government; correct interpretation is ensured by mine visits conducted jointly by provincial and federal representatives. Initial focus is on nonferrous metal mines. The federal Department of Energy, Mines and Resources (EMR) is responsible for a national analysis that is aimed at the early detection of worrisome developments-and their reasons-in the flow from resources to reserves and from reserves to supply of these metals. The heart of the national analysis is the annual construction of a "monitoring curve", showing each metal's aggregated mine production as it would decrease over time if no new reserves and production capacity were to be added from the year of analysis. For a given metal, a comparison of monitoring curves from year to year can reveal early signs of supply stagnation. In anyone year, a monitoring curve in conjunction with foreseen needs for Canadian mine output will show the production gap that would have to be filled from reserves and production capacity yet to be developed. The production gaps for copper, nickel, zinc and lead, the four leading base metals mined in Canada, are shown for the 20-year period ahead, in the context of production achieved during the past 20 years. It is shown that reserve levels commensurate with likely future production levels would require that average annual reserve additions during 1978-98 exceed the average annual additions during the preceding 20 years. Reserve levels of all four metals have declined in recent years. A review of significant discoveries in the last five years suggests that this fall in reserves is not the result of a lack of exploration successes, but of stagnation in development for various economic reasons.

Jan 1, 1979

By John P. Weir

Coal's participation in the domestic energy market depends to a very large extent upon the cost of coal delivered to consumers. Today the principal use of coal in the U.S. is in steam-electric generating stations. Generally, it is the delivered cost per million Btu's that is given the greatest weight in choosing either oil, natural gas or coal as the fuel used in these power plants. There are three major cost components of generating electric energy in steam-electric plants. These expenses expressed in terms of "dollars per kilowatt year" are: (1) operation and maintenance of necessary facilities, (2) fixed charges of necessary capital investment, and (3) fuel. For a modern large plant, the first two items would be approximately as follows:

Jan 9, 1962

By Y. C. Liu

Arsenic bearing copper-gold ores deposit have been found in most areas of China, especially in southwest. Due to the very closed association between arsenic, copper and gold, conventional flotation and cyanide leaching process may not give positive results. An arsenic bearing copper-gold ore in Sichuan province ,with gold grade of 10.12 g/t, 0.6% Cu and 0.14% As, is characterized by superfine grains with -40 microns fraction accounting for 70.9% and the gold enwrapped mainly by pyrite and tennanite accounts for 34.31%. Arsenic in this ore occurs in isomorphism, deposited in tetrahedrite. The ore was processed primarily in two stage flotation to get copper bearing gold concentrate and pyrite bearing gold concentrate respectively, and sequentially processed by leaching. Under the pressure of 300 KPa and 110~115 ?, the copper-gold concentrate was leached by an oxidizing and catalyzing leach agent then copper and gold were separated from each other in leach solution. The pyrite bearing gold concentrate was processed by cyanide leaching with the leach residue as sulfur product. The test results showed that copper recovery was up to 88.89%, gold recovery up to 89.18% and sulfur recovery up to 92.64%.

Jan 1, 2014

By Christiaan Zeilstra, Jan van der Stel, Koen Meijer, Gerard Louwerse, Tim Peeters

The steel industry is producing about 5% of the world wide CO2 emission. Therefore the European steel industry has defined a research program to reduce the CO2 emission by 50% per ton: ULCOS. Since its start in 2004 ULCOS has identified four technologies for further development. Two of these technologies which produce liquid hot metal are discussed. The ULCOS blast furnace is based on recycling of decarbonated topgas and the capture and storage of CO2. The concept has been demonstrated during three campaigns at LKAB EBF in Luleå, Sweden. The smelting reduction process HIsarna is a combination of the cyclone-technology and Hismelt. The process has been demonstrated successfully in four campaigns at a pilot installation on the IJmuiden steelmaking site.

Jan 1, 2015

By Floyd C. Kelley

THE literature of the last decade is rich with information relating to the cause and means of control of grain growth in pure metals, but is deficient concerning the role diffusion plays in grain growth, although during this period many new products that depend on diffusion for their properties and success have been developed. Among these are cementation products, produced by calorizing, chromizing, and carbonizing, or by mixing, pressing, and sintering powdered metals such as Syke's iron-molybdenum die material, Genelite, and Elcon Metal (copper, tungsten) etc. This is a fertile field for new developments, but before it can be utilized to the fullest extent there must be a thorough investigation of the processes by which diffusion and grain growth take place. Grain growth plays no small part in the process and certainly the physical properties of these products depend largely on the grain size and state of equilibrium produced. The field of investigation does not end here, but may be extended to the effect of diffusion on impurities, segregations and dendrites in the broad field of ferrous and non-ferrous metallurgy. A number of years ago the author investigated several of these cases and noted, with striking regularity, the pronounced effect of diffusion in promoting recrystallization and grain growth. An example of this phenomenon is given in his paper on chromizing1 which contained photomicrographs of large radial or columnar crystals produced by diffusion of chromium in the solid state. Another manifestation of this effect was discussed by Austen,2 who showed the part hydrogen plays in the decarburization of steel and the effect of diffusion upon the grain structure. DIFFUSION OF METALS IN IRON It seems to be a general law, whenever two metals are brought into intimate contact at a temperature at which diffusion takes place, that a comparatively rapid, or abnormal, grain growth results. The grains

Jan 1, 1928

By Young W. A.

The Eagle Silver mine is in the Rush Valley mining district, Tooele County, Utah, and is now operated by the Hampton Mining Co. The property, originally referred to as the Argent, is reported to have been one of the first discoveries in the district. The early operators mined ore to a depth of 850 feet, at which point the property was abandoned because of excessive water. During 1905 the Honerine tunnel was driven into the area approximately 1,800 feet below the collar of the Argent shaft. This tunnel served to drain the levels above and operations were resumed. Ore deposits in the Eagle Silver mine occur in the Galena King lime-stone, a 20-to 60-foot member of interbedded quartzite and limestone in the Oquirrh formation of Pennsylvanian age. This member has been faulted along the bedding, forming the Galena King gouge. Mineralization commonly occurs in or near this gouge area in a brecciated, highly altered, pipelike zone. The known ore shoots occur in association with the breccia pipe, commonly adjacent to cross faulting and porphyry intrusions. In general, two ore shoots have been mined on the upper levels of the mine, one lying to the east and the other to the west of the breccia zone. The Bureau of Mines diamond-drilling program was begun during the latter part of 1948 and completed early in 1949. Nine holes were drilled, aggregating 852.8 feet. Sludge and core samples from mineralized sections were analyzed in the Salt Lake City laboratories. A total of 87 sludge, 71 core, and 11 chip samples was submitted for analysis.

Jan 1, 1950