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The sulphides can be arranged in a series determined by the relative amounts of ionic and covalent bonding present. This series is similar to the paragenetic series common to most sulphide ore deposits. Investigation of the surface tensions of the corresponding heavy metal iodides by the maximum bubble pressure method throws some light upon this relationship. It is shown that the surface tension of molten iodides decreases as the chemical bonding within them becomes more covalent. These results are interpreted in terms of the constitution of the melts, and are extended to cover the case of sulphides in solution in a silicate melt. It is concluded that sulphides tend to lower the surface tension of silicate melts and that this tendency becomes greater as the bonding within the dissolved sulphide groups becomes more covalent. A possible relationship between this conclusion and the origin of paragenesis in sulphide ore deposits is indicated.INTRODUCTIONIt is well known that the order of deposition, or paragenesis of sulphide minerals is remarkably similar in hypogene ore deposits throughout the world. This widespread similarity points towards the operation of some fundamental process which must be intimately connected with -the genesis of these ores. A correct interpretation and understanding of the causes of paragenesis in sulphide ore deposits would shed much light on the origin of these deposits.In Table 1 a simplified paragenetic series for sulphide minerals is presented. In most cases, only the most important sulphide of any particular element has been included. The object of this procedure is to simplify the following discussion. Furthermore, it should be realized that this series is only a generalization and that exceptions and reversals of position are quite common. Especially does this...

Jan 1, 1956

By P. W. Godbehere

"INTRODUCTIONMagnetic mill linings have been developed from an invention by Mr. Bertil Brandt, the originator of the Skega rubber lining. The OREBED magnetic mill lining is a concept in which rubber covered strontium ferrite permanent magnets are arranged on the inside wall of a mill shell so that they attract magnetically susceptible material be it ore, media or tramp, to form a protective layer over the magnets and to serve as an operating surface with indefinite life.Noranda Mines Ltd. through its associate Norcast Division of Noranda Metal Industries formed a joint venture with the inventors to market magnetic mill linings in North America. For the past twelve months trials have been undertaken in conjunction with Orebed Inc. to test and develop these linings for grinding mill applications at the Horne Concentrator. Two independent milling circuits are currently being operated, one treating a siliceous gold ore and the other a copper slag.This paper presents the results of the magnetic lining test programme to date."

Jan 1, 1983

By Edwards A. B

A suite of specimens from the newly developed Black Star copper ore body at Mount Isa was made available for mineragraphic study by the Mount Isa Mines, Ltd. The specimens were selected as representative of the different phases of mineralisation found in the ore body, rather than with a view to furnishing a complete cross-section of it; and the examination has been carried out with a view to ascertaining (1) the nature, extent and association of the arsenic, antimony and possibly bismuth, minerals in the ore, (2) the mode of occurrence of silver in the ore, and (3) whether galena and sphalerite occur in minute forms well below the sIzes readily observed in hand specimens.Analyses of the January to June, 1944, mill head composites show that the proportions of the elements Ag, As, Sb and Bi in the ore are as follows:Ag 0.000013 = 0.35 oz./tonAs 0.024Sb 0:002Bi 0.0005The copper content of the mill heads ranges from 3.5% to 4.75%, the lead content from 0.03% to 0.08,% and the zinc content from 0.09% to 0.23%.MINERAL COMPOSITIONThe specimens range from massive sulphide ore, consisting of areas of chalcopyrite, pyrrhotite, and rarely sphalerite, from 1 to 3 cm. across, to fragments of extremely finely banded pyritic shale in which no minerals other than pyrite are visible. The gangue associated with the massive sulphides is chiefly dolomite, and sometimes white quartz. The pyritic shale fragments show evidence of shearing and faulting on a micro-scale, the fractures sometimes being filled with sulphides and vein minerals.The ore minerals found in the polished sections are pyrite, arsenopyrite, marcasite, sphalerite, chalcopyrite, valleriite, chalcostibite, galena, dyscrasite, jamesonite, magnetite, gold, graphite and rutile.Pyrite (FeS2)Pyrite occurs chiefly in two forms according to whether deposition took place along the bedding planes or along the intersecting faults and fractures. Deposition of pyrite along the bedding planes of dense, thinly banded shales ha,s produced a metasomatically altered shale in which the pyritic bands are from 0.02 to 0.03 mm. wide, and alternate with bands...

Jan 1, 1945

By D. Harrington

Educational campaigns conducted by the manufacturers of explosives, the Bureau of Mines, mining companies, and safety organizations have contributed greatly in reducing accidents caused by explosives arid blasting. Despite these campaigns and the dissemination of information, accidents from explosives and blasting continue to be the direct cause of scores of fatalities and hundreds of nonfatal accidents annually, not only in the mineral industry but essentially wherever explosives are used. The experience of many mining companies and other users of explosives has proved that accidents from explosives can be prevented or averted by the proper training of employees in the handling and using of explosives and by the enforcement of definite rules and instructions for their use. Unfortunately, throughout the years numerous false impressions and ideas have grown up and around the use of explosives. Many of these can be traced back to the manner in which the users of explosives were originally taught, if instructed at all; and as with many types of misinformation in nearly all walks of life, those false ideas are decidedly persistent and being so cause much damage. Many if not most of the users of explosives gained their knowledge of explosives and blasting by watching others and more or less "absorbing" the procedures and thrones of the other fellow, who acted unconsciously as teacher or instructor. A study of explosives accidents reveals the results of such "teachings" when the causes of the accidents are determined, and as might be expected the results very often are far from good. One of the most persistently erroneous impressions or ideas is concerned with the burning rate of safety fuse. Many men with

Jan 1, 1944

By Leopoldo Mariscal

El presente trabajo describe los aspectos más importantes del proyecto de Fundición de Ilo como son: la tecnología, el desarrollo de la ingeniería y construcción, el impacto económico, social, tecnológico y ambiental de su ejecución y los planes de entrenamiento y comisionado de la nueva planta. Asimismo considera entre los equipos principales: un horno de fusión en baño ISASMELT asociado a un caldero de recuperación de calor y un precipitador electroestático, cuatro convertidores Peirce Smith, dos electroprecipitadores, dos plantas de ácido, dos plantas de oxigeno, dos plantas de efluentes, una planta de moldeo de ánodos, dos hornos de limpieza de escoria, y varias plantas auxiliares más.

Sep 12, 2005

By C. G. Anderson

Today, with a stringent economic and environmental climate prevailing in the copper business, there is increased interest in evaluating new processing alternatives for production. Hydrometallurgical pressure oxidation of copper concentrates is one of the more viable approaches and several technological candidates have emerged. Of these, an overlooked but, ironically the first industrially proven methodology, utilized nitrogen species catalyzation in the oxidizing pressure leach system to produce copper via SX/EW. Given its many inherent process advantages, this may prove to be a feasible process alternative for the future. In this paper, the history of the system and its application to copper concentrates and ores will be outlined. In particular, a novel methodology for effective recovery of precious metals from chalcopyrite concentrates will be discussed. Finally, the perceived economics of chalcopyrite concentrate treatment with this unique industrially proven process will be delineated.

Jan 1, 2001

By Keith Bowers, Frank Mimnagh, Eddie Woods

The CTRL London Tunnels The Channel Tunnel Rail Link (CTRL) London Tunnels comprise 36km of internal diameter bores that were driven by Earth Pressure Balance (EPB) Tunnel Boring Machines (TBMs). The tunnels were constructed between the autumn of 2002 and the spring of 2004. The permanent works also included the 1.1 km long station box at Stratford, five ventilation shafts of depths between 30 and 54 m, 29 cross passages and various large diameter sprayed concrete lined connecting tunnels. The tunnels were driven under densely populated areas of north and east London, as depicted in Figures 1 to 4. Under the parliamentary CTRL Act the project had obligations to make

Jan 1, 2005

For a large scale open pit mining and concentrating operation, on a low-grade disseminated ore body, it is possible to set an approximate lower bound on economically feasible operating scales and an approximate upper bound on economically desirable scales in a relatively straight forward manner. The optimum scale ofplanned operations, with respect to the objective ofmaximisation ofthe net value ofthe orebody, will have to be arrived at by iterative planning runs, but it may be expected to lie close to this upper bound. The effects of infrastructural costs and of the addition of a risk premium to the cost of capital, to form the discount rate for planning purposes, are considered theoretically and by worked example. It is concluded that a perceived special, unsystematic, risk should not be accounted for by the use of such a risk premium as this is inducive to placing a greater amount of investment capital at risk, for no greater return-rate to investment.

Jan 1, 1986

By Jesse A. Miller

ALTHOUGH the element titanium was discovered by William Gregor in 1790, over a hundred years passed before it was put to commercial use. The first commercial application of titanium was as an alloy additive to iron and steel, and the first ferroalloys were produced domestically in 1906. Titanium pigments were developed somewhat later and have been produced in the United States since 1918. The use of titaniferous material in welding-rod coatings first gained acceptance ill the mid-30's. The metal titanium has only had commercial importance since 1948; domestic production for that year was 10 tons. The relative importance of these major uses of titanium in various forms may he gaged by the consumption of titanium dioxide (Ti02) for these purposes in 1954. Of a total of 440,000 short tons of Ti02 consumed in 1954, 95 percent of the total was consumed for pigments; 2 percent for welding-rod coatings; 1 percent for non-titanium-base alloys and carbide; and 2 percent for miscellaneous uses. The titanium-metal industry is in its infancy, but it has more than doubled its output every year from 1948 to 1954, reaching 5,370 short tons in 1954.

Jan 1, 1957

Open cut mining of the Black Rock chalcocite ore started in 1963. A ground movement monitoring programme was commencing in the early stages of mining when signs of instabilityof the western wall became apparent. Eventually 100.000 cu vd, of overburden Were removed beyond the rim of the western wall in an attempt to stabilize the slope. Subsequent decpenlug and mining till the final batter angle of 45 resulted in deterioration and mining was stopped 38 ft short in the ulltimte design deplh of 520 ft.Investigations showed that the geology of the western wall , was a major factor in the instability of this wall. A block jointed model was made 10 illustrate some of the pehomena observed. Quallatative agreement was found between the model deformation and the field measurements obtained.The results of the monitoring programme clearly show the value of this work In respect to the conlrol of the mining operatIon...

Jan 1, 1968

By T. J. Serenko

The epithermal deposit is hosted by Tertiary volcanic rocks that lie between mid-Miocene normal faults of the Northern Nevada Rift. Petrographic, laser-ablation and metallurgical observations suggested that the gold occurs in two principal forms: native (and electrum) and disseminated in arsenopyrite. It was proposed that gold is distributed between two parageneses with distinct mineralogical associations. Detailed downhole geochemical study supported the observations. Concentrations of Au, Ag, As, Sb and Se were determined from drill core and reverse-circulation cutting composites and contoured on cross-sections. Gold was indeed shown to have a bimodal distribution with the two parts separated spatially and perhaps temporally, implying that two separate genetic processes acted to concentrate gold at Mule Canyon

Aug 1, 1995

By A. P. E. Dirige

Extensive field study has been performed to assess the capabilities of thin sprayon liners (TSLs) and conventional spray-on support systems for preventing rock and support material damage that often results due to mining-induced rockbursts. Support performance was studied using field scale explosive detonation trials to simulate dynamic failure effects that are known to develop during typical rockburst events. Multiple seismic and high speed photographic monitoring techniques were used to provide detailed information concerning rock motion, surface fracturing, ejected fragment motion, and support liner survivability characteristics. Results of this study have demonstrated that TSL?s and variant layer combinations may be as effective as or better than conventional support materials for mitigating rockburst or like damage in highly stressed mine environments. In this study, field results have been verified using numerical modeling procedures to better understand the support behaviour of TSLs when subjected to highly stressed mine environments and mining-induced rockbursts, a factor that is essential when designing any rock support system. A series of numerical modeling assessments were conducted using FLAC3D modeling of a half circular TSL-lined tunnel, influenced by anisotropic stresses and simulated mining-induced rockbursts, to investigate the support potential of TSLs under prototype conditions. The effect of a mine rockburst was simulated using the three-dimensional dynamic analysis option of FLAC3D. Results of TSL-lined tunnels in highly stressed and mine rockburst conditions indicated exceptional effectiveness of TSLs for suppressing rock deterioration resulting from stresses and rockbursts. The rock support potential of TSLs on tunnel surfaces was compared with that of thin shotcrete linings, and results indicated that thin spray-on lining products currently available may be equally as effective in support as shotcrete materials.

May 1, 2009

By D Jensen, L Riffo, S Yu, F Traczyk, D Meadows

With the steady increase of molybdenum demand worldwide and the favorable molybdenum market, many technological innovations on both process and equipment have been developed and applied in many modern molybdenum plants around the world. This paper introduces the most commonly used molybdenum flotation flowsheet, together with the introduction of the flotation chemistry. Many different types of flotation cells are used in modern moly plants, and each type of flotation cell has its own unique advantages suited for particular ore and process conditions. This paper tries to provide some insight and guidelines in flowsheet development and flotation cell selection in the molybdenum plants.CITATION:Meadows, D, Jensen, D, Traczyk, F, Yu, S and Riffo, L, 2013. Molybdenum flotation circuit and flotation cells, in Proceedings MetPlant 2013 , pp 387-398 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Alexander Filotti, Stanley Merjan

"Abstract. The paper shows the benefits and accomplishments of this relatively new but established product on the pile foundations market in the United States. The first part of the paper describes general aspects of the design, construction, and geotechnical capacity (designed and in situ) of Tapertube piles. The qualities resulting from the design and manufacturing of the Tapertube pile will be presented first.The second part of the paper describes the installation of Tapertube piles for an addition to Terminal One at JFK International Airport and The Edge development. A carbon print analysis for both projects is developed using the EFFC-DFI carbon print calculator. For the JFK project the benefits of using BIM in redesigning the project for Tapertube piles are explored.General description.The tapertube pile consists of a tapered tubular bottom section attached to a conventional pipe extension. The 50 ksi steel for the taper is mechanically folded into a polygonal cross-section (usually 12-sided) with a longitudinal welded seam. The tapers are fabricated in many sizes with bottom diameters varying from 8 to 14 inches, top diameters from 12 to 20 inches, lengths from 10 to 35 feet, and steel thicknesses from 3/16 to 1/2 inch. A conical steel shoe or a flat plate is welded to the bottom of the taper and the top of the taper is circularized to match the outside diameter of the pipe extension. The inclination of the tapers is generally between 1.5% and 2.5%.The pipe extension is fully butt welded to the taper and has the necessary length for the pile to develop the requisite capacity. Concrete fill for the piles is generally 4,000 p.s.i. or more. Typically the piles are shopassembled and shipped to jobsites in lengths to 80 feet."

Jan 1, 2014

By Roberts W. P H, Chant R. A

Investigation of the "whole-rock" major element geochemistry of the Broken Hill lodes and of the rocks immediately enclosing them has been carried out on the full lengths of 19 diamond drill cores transecting B lode,A lode, No. 1 lens and Lead lode in The Zinc Corporation Ltd.-New Broken Hill Consolidated Limited, at the southern end of the line of lode.It appears that the abundances of all of the principal "non-sulphide components" - Si02, AI2O3, Ti02, CaO, MgO, MnO, K2O, TiO2 and P203 - are closely tied to the incidence of sulphide. The well-known direct relationship of calcium and manganese with the incidence of sulphide is confirmed, and to this is now added the pairing sulpnide-phosphate, which is particularly welldeveloped in the zinc lodes. It is also now shown that there is a clear inverse relationship between sulphide on one hand and AI2O3, Ti02 , MgO, and K2O on the other.Total Fe-which is an important constituent of both sulphide and non-sulphide-appears to occur in essentially similar amounts in ore and enclosing materials. The incidence of Na20, while generally depressed in ore, issomewhat erratic and equivocal. Si02 and sulphide usually show a highly systematic inverse relationship-a feature stemming inevitably from their being by far the two most abundant, and hence two co-dominant, materials ofthe ores.These features of elemental abundance are interpreted in the context of seaflooor hydrothermal ore deposition to give some insight into the amount and nature of detrital and of chemical sedimentation, the formation and accumulation of different clay minerals, the chemical and physical characteristics of the bottom waters, and the reasons for the comparative paucity of iron in the Broken Hill lode.

Jan 1, 1978

By Pat Wilmoth, Joseph P. Gildner, Dan Nowak, Shane Yanagisawa, Don Z. Painter, Gordon F. Revey

Frontier/Traylor is presently completing construction of twin tunnels for the Tri-County Metropolitan Transit District of Oregon’s (Tri-Met) westside lightrail system. The tunnels are each 4,550 m (14,935 ft) in length and 6.48 m (21.29 ft) in diameter. The 1/3 of each tunnel was driven from the west portal using drill and blast methods and the remaining 2/3 was driven from the east portal using a TBM. The paper describes: The difficulties encountered by the TBM mining the weathered Columbia River Basalts. The execution of drill and blast work despite challenging ground conditions, stringent noise and vibrations specifications, and public relations problems. The excavation and lining of the Washington Park Station 79 m (260 ft) below the park zoo.

Jan 1, 1997

The published liquidus data on the Pb-PbS system have been correlated on the basis of one-coefficient Margules equations. Thermodynamic properties of the components of this system have been obtained, and it has also been found that the calculated miscibility gap of this system exists over a very narrow range of temperature (1041 to 1058°C).

Jan 1, 1972

By Flavio Begazo Mamani

Recientemente Southern Perú desarrolló un nuevo proyecto donde se modernizaba la planta de Fundicion y se reemplazaba el convencional horno reverbero por la tecnología del ISASMELT, capturando más del 92% de los gases generados durante el proceso de fusión de los concentrados de cobre. En ese sentido, el presente texto describo los efectos de la modernización de la Fundición sobre la calidad anódica. Antes de la modernización de la Fundición, los ánodos fueron producidos en la planta de ánodos ubicada en la Refinería de Cobre de Ilo. Ahora los ánodos son producidos directamente en la Fundición y como resultado, la composición química de los ánodos ha cambiado, principalmente en el contenido de bismuto, antimonio, plomo y zinc, siendo diferentes a los parámetros de diseño original de la Refinería. Asimismo, este factor impulsó a revisar el proceso de remoción de impurezas y los parámetros de la refinación electrolítica en la Refinería para evitar la contaminación del cobre refinado, logrando mantener la continuidad de la producción de cátodos de cobre de alta calidad superando los estándares interna-cionales de la norma ASTM-B115.

Sep 12, 2011

Satellite Image Based Strategies to Evaluate the Impact of Dismissed Mine Site - An Application to the Mae Moh Coal Mine Area in the Lampang Province, Thailand

Sep 13, 2010

Rio Tinto has embarked on a journey to use automation to improve the performance of its surface mines. The driver for automation is to improve the accuracy and consistency of mining processes and less to do with cost savings through labour reduction. A key task in most surface mines is blasthole drilling. The degree to how well this is done cascades through the downstream mining process. It impacts scheduling, excavation, slope stability, material handling, beneficiation and final product blending. Improved blasthole drilling was identified as an objective that has a significant business case in most of Rio Tinto's surface mines. This paper describes Rio Tinto's drill enhancement project that has developed a robust system for automating most of the functions on a Terex SKSS16 drill rig. Automated drilling is currently being used in production at the West Angelas iron ore mine in the Pilbara region of Western Australia. A description of the essential elements of the drill automation system is given together with an overview of how automated drilling is performed remotely from the mine office. A review of some of the benefits of the enhanced drill system is given together with the future plans to extend the functionality of the automated drill and the expected benefits.

May 1, 2010