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By Jaidev Sankar

The dream of constructing the new Second Avenue Subway in New York has finally become reality as the first construction contract package is currently underway. This first contract requires the construction a TBM Launch Box in the middle of Second Avenue from which a Tunnel Boring Machine (TBM) will bore two tunnels south to 63rd Street. This paper will discuss the design of this contract and how construction has progressed including preparation, site constraints, utility construction and com-munity impacts while highlighting the challenges of working in an urban environment. It will also discuss moving forward on this major project outlining the remaining contract packages including their scope and status.

By Jana Dobrovska

The paper deals with new approach for measurement and evaluation of chemical microheterogeneity of elements in polycomponent metallic systems (i. e. steels, Ni-alloys). The method is based on the original mathematical model for determination of distribution curves of dendritic segregation of selected elements and on the original mathematical model for determination of the effective partition coefficients of these elements in the structure of analyzed alloy. Application of the method at research of chemical heterogeneity of continuously cast steel slab is also presented. The original results of measurement of dendritic microheterogeneity of eight elements (Al, Si, P, S, Ti, Cr, Mn and Fe) in structure of nine zones of a transversal section of slab are given.

Jan 1, 2006

By Pengfu Tan

Lead blast-furnace bullion cools to near its freezing point in an operation known as copper drossing or hot drossing usually contains 0.02-0.06% copper. The removal of this copper is usually carried out in a batch operation known as sulfur drossing. Sulfur is stirred into the bullion at temperatures near its freezing point, and the dross of copper and lead sulfides that floats to the surface is skimmed off manually. A thermodynamic model has been developed to simulate the copper drossing. The phase diagram of Pb-Cu-S system has been calculated, and the effects of the process parameters, such as temperature, copper content, and sulfur content, on the drossing process have been simulated and discussed.

Jan 1, 2006

By Kerry Gee, Gary Colgan, James Fricke

Introduction Elevated zinc concentrations are observed in groundwater within alluvium adjacent to Silver Creek east of Park City, Utah. The study area is located in a small valley one and one-half miles northeast of Park City, Utah in Summit County, Utah (Figure 1). Although surface water concentrations in Silver Creek are typically less than 1 mg/l, groundwater concentrations have been measured as high as 85 mg/l in a near neutral pH environment. The elevated zinc concentrations in groundwater result from several factors including: (1) dissolution of zinc from tailings exposed at the surface and within the alluvium, (2) oxidizing conditions created by surface/ground-water exchange, and (3) ideal geochemical conditions for the dissolution of zinc-containing minerals. These ideal conditions include readily soluble minerals, available anions for complexation, and lack of available surface adsorption sites.

Jan 1, 2005

An examination is made of some of the consequences of a magmatic gas phase developed during a late stage of differentiation of an acidic magma. Elements possessing halides with high partial pressures (Sn, Mo, W) may be removed from the magma by distillation into gas bubbles in the manner suggested by Fenner (1933). The common chalcophile elements are not affected by this mechanism, but form sulphides which may become attached to rising gas bubbles by one of three distinct mechanisms. The gas bubbles may then carry the sulphides upwards and concentrate them in some favourable locus, giving rise to an ore-forming fluid. The process would operate selectively upon different sulphides and is capable of providing an explanation of the paragenetic succession observed in ore deposits as well as other important geological criteria of ore genesis.INTRODUCTIONThere is a widespread belief among contemporary geologists that a large and important class of ore deposits is genetically related in some way·to acidic igneous rocks. This class includes the tin-tungsten-molybdenum-bismuth type of mineralization as well as a variety of sulphide deposits.A basic problem confronting explanation of the genesis of these deposits is the manner in which trace elements which were originally widely dispersed in granitic magmas were segregated therefrom and concentrated into economic mineral deposits.The principles underlying the formation of one group of minerals deposits (pegmatites) related to granitic magmas ate reasonably well understood, largely due to the labours of Goldschmidt and his school. However, many geologists have noted that there appears to be some sort of fundamental discontinuity between pegmatite formation and the origin of the more common hypogene ores, particularly sulphides.Accordingly it has been suggested that these ores...

Jan 1, 1956

By W. W. Culver

The paper explores the substance, circumstances and significance of the Whelpley and Storer Copper Process. The 1866 Whelpley and Storer patent specified a process combining mechanical and chemical engineering. The process called for a down-drafting shaft furnace with a horizontal flue connected at the bottom of the shaft. Powdered sulphide ore was roasted in the shaft and then sent forward fully oxidized to a bath of sulphuric acid and/or calcium chloride. The “water furnace” was developed in Boston, at a time when the city was home to most Michigan copper mining companies. The process was field-tested at Quebec’s Harvey Hill copper mine. In 1865 James Douglas, Jr. took over management of the Harvey Hill mine with the challenge of saving the family investment. He needed a way to make money from low-grade sulphides. Through his relationship with chemist T. Sterry Hunt, Douglas learned of a possible way ahead using the process developed by Whelpley and Storer. The paper confirms the centrality of publications, meetings, and networking in the advancement of metallurgy. The process is of interest historically, as much as anything, because it is one of the pillars of James Douglas’ distinguished career in copper. INTRODUCTION At the 1866 meeting of the American Association for the Advancement of Science (AAAS) in Buffalo, New York, T. Sterry Hunt (1826–1892) read a paper “On the Metallurgical System of Messrs. Whelpley and Storer.” The paper is part of a chain of events that constitute the foundation of James Douglas’ (1837–1918) success in the copper mining industry. To understand the career of Douglas over the early years of modern copper mining, we must necessarily start with Whelpley and Storer. Going back to Hunt’s paper, he concluded his remarks by asserting that the Whelpley and Storer Process was “capable of such wide and varied application, that it is probably destined to have a very important influence on the industry of the world” (Hunt, 1867a). He reached this conclusion reasoning that the process had overcome a critical metallurgical hurdle (Hunt, 1867a). Hunt, a geo-chemist in modern terms, recalled that the chemist of those years easily separated copper from “sulphuretted” ores by converting it to a soluble salt from which pure metal was precipitated by “an equivalent of iron.” The problem was to “…apply this principle in the working of copper ores on a great scale...” (Hunt, 1867a). Hunt noted that this very problem had “…engaged the attention of many metallurgists, and has given rise to various processes for obtaining copper by the moist way, many of which are nearly or quite perfect in their operation, but are lacking in practicability and cheapness” (Hunt, 1867a). Hunt thought Whelpley and Storer had overcome the low-grade sulphide hurdle with a commercially viable engineering breakthrough. Yet in the history of copper metallurgy, the process is missing. What happened?

Jan 1, 2019

The principal dirnensions of the chimney were fixed as follows: Height from formation to coping, 328 ft. 8 in.; inside diameter concrete shell, 13 ft. Gin.; inside diameter of the 4~-in. brick lining. 11 ft. (j in. ; shell thickness above flue inlet at a point 39 ft. above formation, 1 ft. 8in.; shell thickness at coping, 6 in. That is, the inside of chimney is cylindrical, wldst the outside is gradually stepped inwards with of 1 in. and less until the shell is 6 in. thick only at the top. With these dimensions in mind, it will be seen that some close thought was necessary to ensure a satisfactory of fonn which could be kept rigid and plumb to a height and at the same time provide safe working conditions for the labourers employed.FOUNDATIONSThe spread base of the chimney is 45 ft. in diameter, and foundations were carried down to a depth of 8 ft. 6 in. below natural surface into good hard clay which was known to be the best foundation obtainable in the vicinity being capable of withstanding, when dry, a load of 3 tons to 4 tons per square foot, whereas dead load is 1A tons per square foot and the maximum load expeeted under the most severe wind condition is 2 tons per square foot to ensure the foundation being kept dry and unaffected by ground water, the site was surrounded by a ring drain at a distance of six feet from edge of concrete foundation and at a minimum depth of one foot below bottom of concrete. Open-jointed pipes were laid in the bottom ofthe drain and graded to a pipe drain with outfall clear of the site.

Jan 1, 1924

By Anthony J. Konya

"This paper was written during part of the author’s student co-op with Cargill Salt at its Avery Islandunderground salt mine in Louisiana. Blasting salt is a unique type of blasting that is different than blasting other rock types. The plastic nature of salt, along with its large swell factor make salt a challenge to blast. The Cargill salt mines use and have tested a variety of different methods for breaking salt in an efficient manner, however these blasting methods are rarely used in other operations nor talked about today."

Jan 1, 2016

By Whang K, Choi H

A study of flocculation of ultra-fine coal particles by ultrasonic waves was investigated on a laboratory scale.The coal suspension was dilute, with low ionic strength, and at pH 6·2.When a stationary sonic wave is set up in a solution containing suspended coal particles, it is believed that high and low pressure regions are alternately established at the half wave-length of the sonic wave and this resultsin the migration of coal particles towards the low pressure regions.As expected the flocculation is more effective as to frequency and the power of the ultrasonic waves is increased.The shape and size of the test equipment are also important variables.

Jan 1, 1977

By Ihsan Berk Tulu, Mark Van Dyke, Ted Klemetti, Deniz Tuncay

"Longwall abutment loads are influenced by several factors, including depth of cover, pillar sizes, panel dimensions, geological setting, mining height, proximity to gob, intersection type, and size of the gob. How does proximity to the gob affect pillar loading and entry condition? Does the gob influence depend on whether the abutment load is a forward, side, or rear loading? Do non-typical bleeder entry systems follow the traditional front and side abutment loading and extent concepts? If not, will an improved understanding of the combined abutment extent warrant a change in pillar design or standing support in bleeder entries?This paper details observations made in the non-typical bleeder entries of a moderate depth longwall panel; specifically, it explores data collected from borehole pressure cells and roof extensometers, observations of the conditions of the entries, and numerical modeling of the bleeder entries during longwall extraction. The primary focus was the extent and magnitude of the abutment loading experienced due to the extraction of the longwall panels. Due to the layout of the longwall panels and bleeder entries, the borehole pressure cells (BPCs) and roof extensometers did not show much change due to the advancing of the first longwall. However, they did show a noticeable increase due to the second longwall advancement, a maximum of about 4 MPa of pressure increase and 5 mm of roof deformation. The observations of the conditions showed little to no change from before the first longwall panel extraction began to when the second longwall panel had been advanced more than 915 meters. Localized pillar spalling was observed on the corners of the pillars closest to the longwall gob as was an increase in water in the entries. In addition to the observations and instrumentation, numerical modeling was performed to validate modeling procedures against the monitoring results and evaluate the bleeder design. ITASCA Consulting Group’s FLAC3D numerical modeling software was used to evaluate the bleeder entries. The results of the models indicated only a minor increase in load during the extraction of the longwall panels. These models showed a much greater increase in stress due to the development of the gateroad and bleeder entries—about 80% development and 20% longwall extraction. The FLAC3D model showed very good correlation between modeled and expected gateroad loading during panel extraction. The front and side abutment extent modeled was very similar to observations from this and previous panels."

Jan 1, 2019

By Shinji Sassa, Naoki Takahashi, Eiji Kohama, Wakaki Tsuda, Hidenori Takahashi, Ikuo Towhata, Yoshiyuki Morikawa

"Abstract Deep mixing method has been employed increasingly in recent years as a countermeasure against subsoil liquefaction. Column-type solidification, however, has been thought to have little effect as a liquefaction countermeasure, because the shear deformation of unimproved soil between the columns cannot be reduced. In recent years, experimental results have been reported that imply that solidified columns can reduce the shear deformation of unimproved soil around them. A new arrangement has been proposed to mitigate lateral flow induced by liquefaction. In this study, a series of dynamic centrifuge model tests was conducted to verify the lateral flow resistance of stabilized columns. The results indicate that stabilized columns can reduce the lateral flow of liquefied ground if the column displacement and the column head rotation are restricted. This paper concludes that it is important to restrict the displacement and the rotation of the column head by surface improvement to mitigate the lateral flow of liquefied ground.INTRODUCTIONDeep mixing method has been employed increasingly in recent years as a countermeasure against subsoil liquefaction. The solidified body formed by the deep mixing method is usually block or lattice shape, composed of solidified columns that overlap each other horizontally. Lattice-type solidification has been shown to be effective as a liquefaction countermeasure despite the presence of unimproved soil inside the lattice wall, because the shear deformation of the interior soil is restrained by the wall (Suzuki et al., 1989). On the other hand, it has been thought that column-type solidification cannot reduce shear deformation of unimproved soil around columns, because the displacement of a solidified column is less restricted than that of a lattice wall. Column-type solidification has been reported to have little effect as a liquefaction countermeasure, but to be superior in terms of construction cost and applicability around existing underground structures (Koga et al., 1986). However, there are experimental results implying that solidified columns have reduced the shear deformation of unimproved soil and mitigated its liquefaction (Yasuda et al., 2003; Tanaka et al., 2003). Yamamoto et al. (2006) conducted dynamic analyses of ground improved with lattice- and column-type solidification. Their results showed that column-type solidification with an improvement ratio of more than 35% reduces excess pore water pressure generated by earthquakes. Furthermore, the new column arrangement shown in Figure 1(a) has been proposed to mitigate lateral flow induced by liquefaction. It was developed and has been verified using dynamic model testing in a 1 g field (Takahashi et al., 2010a; 2010b; 2013; Towhata et al., 2010). The stabilized columns in this configuration interrupt lateral flow in any direction, unlike those placed in square and triangular arrangements."

Jan 1, 2014

By J Loimi, P Minkkinen, T Korpela

The head loss caused by metallurgical sampling for slurry streams can be reduced by metallurgical sampler design. When the process volumetric flow rate is reduced by vertical static cutters before the sampling by an equal number of moving cutters to the static cutters, the installation requires less installation head space than other sampling arrangements and is easy to accommodate at suitable locations in the process. Low head loss reduces building costs for the processing plant and operational costs during the lifetime of the plant.The presence of a possible systematic bias in the particle size distribution, solids density and elemental composition between an Outotec MSA 2/50 metallurgical slurry sampler sample and MSA 2/50 manually sampled reject have been studied by a customer. The paired samples were taken as simultaneously as possible. The customer evaluated the possible bias using a paired t-test and provided the assay results to Outotec for further evaluation.The results of the paired t-test showed no systematic bias in particle size distribution, solid density or assayed analytes, except in one analyte with low content and a high relative error. The high relative error in one analyte may have been caused by the same calibration model used in a X-ray fluorescence analyser for both high elemental-content concentrate and very low elemental-content tailings samples. The sampled stream is the tailings of a previous process stage.The results of the t-test were studied further using analysis of variance to reveal the error sources in samples. The results showed no bias between the samples collected from the MSA 2/50 reject and composite samples collected of the MSA 2/50 sample stream. The courier online analyser data was also available for evaluation of representativeness to the process stream.The analysis results of the courier online analysis reveals no bias between the MSA 2/50 reject samples, MSA 2/50 sample stream composite samples and online analysis results during the comparative sample collection period.CITATION:Loimi, J, Minkkinen, P and Korpela, T, 2017. Comparative evaluation of manual sampling and Outotec MSA 2/50 metallurgical slurry sampler, in Proceedings Eighth World Conference on Sampling and Blending , pp 167–172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

The stability of parallel underground coal mine galleries and pillars have been investigated using two- and three-dimensional (3D) numerical stress analysis. Anisotropic horizontal in situ stresses and the direction of the excavations have been considered in the numerical analysis. The stability of the tunnels driven in a coal seam at various working depths has been investigated taking into account different strata conditions and then results from two- and three-dimensional numerical modelling studies were compared. Maximum principal stress components have been chosen in three various directions: vertical, parallel and perpendicular to the tunnel axis. Analysis have shown that in the anisotropic in situ stress field, the favourable direction of underground mine openings which have different strata conditions depend not only on the horizontal in situ stresses but also on the vertical in situ stresses. Furthermore, 3D numerical modelling studies have been carried out to investigate stability of multiple entry longwall panel gate roads and pillars with various width-to-length ratios (W/L). Results of the modelling studies have shown that the critical dimension of coal pillars depends on their width and the direction of maximum horizontal stresses.

Dec 6, 2010

Chelopech Mining EAD and Best Available Techniques for Management of Waste Rock in Mining Activities

Sep 13, 2010

By C De-Vitry

"The large Yandi channel iron deposit (CID) is located in the north-west of Western Australia and is currently mined via open pit methods. Drilling at Yandi is widely spaced and current estimates are mostly linear averages of the surrounding local samples. Linear estimates such as ordinary kriging (OK) based on block sizes that are significantly smaller than the dimensions of the drilling grid are less variable than the unknown reality (Armstrong and Champigny, 1989).Conditional simulation (CS) provides a series of plausible realisations that represent the actual grade variability at a small scale (eg 1 m + 1 m + 1 m). These simulations are very useful for a number of purposes, eg: optimising grade control, stockpiling and blending selection of optimal drill hole spacing assessing resource risk on contained tonnage and metal.At Yandi the major constituents of the ore (Fe, P2O5, SiO2, Al2O3 and LOI) are correlated to varying degrees. Independent CS of each assay variable will not reproduce these correlations. Reproducing the correlations (and the shape of scatterplots) is important if the simulations are used for the abovementioned purposes. This paper examines and compares various methods of CS that aim to reproduce the correlations between the assay variables.The CS methods evaluated in this paper are conditional co-simulation (CCS) using the linear model of co-regionalisation and two other, alternative multivariate simulation methods, which use min/max autocorrelation factors (MAF) or the stepwise conditional transform (SCT) to de-correlate assay variables before performing independent CS. It was found that CCS best reproduced the characteristics (histograms, variogram, scatterplots, etc) of the declustered drill hole data (Figure 1). Whilst simulation using MAF generally produced acceptable results, the method did not adequately reproduce the variance of the assay variables. The univariate statistics, histograms and experimental variograms were acceptable for simulations generated from the SCT. Bivariate statistics, cross-variograms and scatterplot reproduction for the SCT were unacceptable. The latter method produced inferior results because there were insufficient samples to obtain a reliable transform of the third assay variable in the transformation sequence.None of the abovementioned simulation methods provides good reproduction of all the scatterplots. This is due to the presence of clay pods, which cause some scatterplots to display two trends. These clay pods contain higher percentages of SiO2 and Al2O3 than the surrounding CID. The clay pods are generally smaller than the drill-grid dimensions. Thus their locations are typically unknown and they cannot be defined by manual interpretation, eg via wireframes. The locations of the clay pods were simulated via indicator CS. CCS was then performed separately for the clay pods and the CID. This significantly improved the reproduction of the correlation coefficients, the scatterplots and visually the simulation was more geologically realistic. Simulating the location of clay pods followed by CCS of assay variables is the recommended approach for simulation at the Yandi CID.CITATION:De-Vitry, C, 2013. Simulation of correlated assay variables - a case study from the Yandi Channel iron deposit, in Proceedings Iron Ore 2013, pp 137-148 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By C E. J de Ronde, I C. Wright

Oceanic subduction-related volcanic frontal arcs extend over 20 000 km within the western Pacific basin and over 21 500 km worldwide, yet they remain largely unexplored with respect to active seafloor mineralization. Systematic exploration of 26 major submarine volcanoes along ~840 km of the Kermadec arc northeast of New Zealand has documented ten (39 per cent) as being hydrothermally active. This frequency of venting is comparable to that on slow-to-moderate rate spreading mid-ocean ridges, which comprise ~80 per cent of the 60 000 km-long global system of spreading centers. The chemistry of fluids discharged from the Kermadec arc volcanoes is moderated by magmatic components in both the gaseous (CO2 + SO2-H2S) and liquid (Fe) phases at very high concentration.The high frequency of venting coupled with chemically rich discharge discovered during this first systematic survey of any arc system forecasts submarine arcs as being important sources of chemicals to the oceans and as potentially lucrative exploration sites for seafloor mineralization. The exploration protocols developed during these surveys include bathymetric mapping of mostly unknown volcanic edifices, followed by detailed water column profiling and sampling to detect and characterize volcanic fluid emission signatures. These procedures are being refined as the survey progresses, both for efficiency and as direct seafloor observations become available for predictive application of water column plume information to guide seafloor mineral exploration.

Jan 1, 2002

By Wolfgang G. Brunner

The center of Berlin is currently a huge jobsite, where international architects, designers, consultants, construction and ground engineers as well as investors take on the challenge of the biggest and probably most complicated projects in terms of soil conditions in Europe. The Berlin sand is generally suitable for foundation measures, but can be very tricky in deep excavation pits below the high ground water level. The reason for this is its uniform grading, medium dense stratification and lack of cohesion. The requirements for these deep pits are: - measurements in the range of up to 120 000 m2 per pit - depths up to 19 m below ground water level - lack of dense horizontal geological layers - no permission for lowering ground water levels - toughest ever European competition in construction. Sheet pile walls, sheet piles set into cut - off walls, secant pile walls, diaphragm walls, all with tie backs under high water pressure, are used as retaining sytems. The pits are closed at the bottom against water either by under water concrete, deep lying grouted cut - offs or high lying jet - grouted cut - off slabs. The huge dimensions of these excavation pits are a new challenge for ground engineers, and new technology had to solve the upcoming problems and resulted in new experience.

Jan 1, 1999

Unrelieved residual strains can influence the states of stress in rock masses. If cheap, stable structures are to be constructed in Tock in which large pressures are exterted by unrelieved residual strains, the pressures must be either utilized or neutralized. A photoelastic technique has been used to show that the release of residual strains in rocks is influenced by the mechanical properties of anisotropic rock fabrics. The relationships between directions of residual strain release and the attitudes of minor geological structures have been determined. For engineering design purposes it is possible to estimate the principal stress directions in rock containing unrelieved residual strains if the attitudes of such minor geological structures as foliation planes, lineations, and joints are known.INTRODUCTIONQuarry workers have long been aware that near-surface rocks may be highly stressed. In many cases the stresses are too large to be the result of gravitational loads. Dale (1923, pp. 34-35) gives many instances of deformation produced by the violent release of residual strains in quarry rocks. Coates (1963) has described powerful rock bursts and cases of rock deformation underground implying the existence of much larger stresses than are likely to result from present-day gravitational loads. The only explanation is that pressures of up to several thousands of pounds per square inch may be caused by unrelieved residual strains in rock.Instruments have been developed for measuring states of stress in rock masses. Most stress determinations in rock have been made on the assumption that rock behaves as a simple elastic material. It is now known that rock is a...

Jan 1, 1964

By Robert W. Bergwall

The $58,000,000.00 Columbia Heights Metro Station project (Section E3-a) forms a part of the Washington Metropolitan Area Transit Authority's (WMATA) Greenbelt Route - Green Line subway system. The Greenbelt route is one often segments that make up WMATA's subway system. Construction of the "cut and cover" reinforced concrete station includes 600 linear feet of an underground center platform, two ancillary service areas totaling 466 linear feet, two surface entrances, and vent shafts (See Figure No. 1). Station subgrade is approximately 60 feet below existing grade. The project can be divided into five main areas: 1. North Service Rooms and Passageway; 2. West Entrance and West Passageway; 3. East Entrance; 4. Center Platform; 5. South Service Rooms. Station dimensions are approximately 1068 feet long by 64 feet wide. Construction commenced at the site in January of 1995 and is expected to be completed by December of 1999. Franki Northwest Company, Crofton, Maryland, was awarded a subcontract by general contractor Blake Construction Company, Washington, D.C, to install the support of excavation and temporary decking systems. Franki's scope of work included the installation of 490 drilled soldier piles plus two elevator shafts totaling 29,700 linear feet of drilling; 1,150 tons of steel decking covered by 37,000. square feet of precast concrete deck planks; 120,000. square feet of timber lagging; 2,500. tons of struts and wales; and temporary support of underground utilities. In conjunction with Franki's work, Bencor Corporation of America, Dallas, Texas, constructed parallel, 600 foot long slurry walls which serve as permanent walls for the center platform portion of the station.

Jan 1, 1997

By R. Jackman, D. Koningen, G. Wilcox

"Gowest Gold Ltd. is in the process of developing the Frankfield East gold deposit located along the largely undeveloped Pipestone fault northeast of Timmins, Ontario. In addition to resource development and environmental permitting work the company has had an ongoing program of metallurgical and engineering studies aimed at evaluating options for processing the Frankfield East ore. Mineralization at the Frankfield project contains arsenopyrite and pyrite as the major sulphide minerals. Bulk flotation of all sulphides results in extremely high gold recovery. However, the gold is almost entirely associated with the arsenopyrite fraction of the ore and is refractory in nature requiring preoxidation treatment. Selective flotation was investigated to recover a gold-arsenopyrite concentrate thereby reducing the mass which would be subjected to further gold processing. As part of this work, a pyrite concentrate low in arsenic content was also recovered that would be suitable as a source of sulphur for a smelter (or other pyrometallurgical facility). Production of separate arsenopyrite and pyrite concentrates is frequently examined but rarely adopted due to the distribution of gold between the two products or the inability to achieve adequate separation. Several flowsheet options were investigated in the study. The best results were achieved following a sequential flotation flowsheet. The flowsheet configuration was key to meeting the targets for the two products. In this paper, the various options investigated are reviewed and the results of the final flowsheet are presented. The overall plan by Gowest was to evaluate all process options to bring the Frankfield East deposit into production. The ability to effectively separate the arsenopyrite and pyrite components in the ore provides Gowest with added opportunities to pursue both short and long term production scenarios."

Jan 1, 2012