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West Perth, Australia

Robinson T.,Republic Alternative Technologies Pty. Ltd. | White D.,Snowden Mining Industry Consultants | Grassi R.,Amec Foster Wheeler
TMS Annual Meeting | Year: 2013

Acid mist abatement in base metal electrowinning cellhouses has advanced rapidly over the last 15 years as a result of both occupational health and economic pressures. Enablers include evolving designs and improved materials of construction. Cellhouse designs now typically include addition of surface tension modifying agents, cell hoods, and anode bags or anode skirts to reduce acid mist production. Automation is increasingly being considered to remove operators from the acid mist containing environment. In nickel electrowinning, chloride based anode bag technologies for chlorine recovery has been adapted to sulfate based systems. These improved technologies and design trends have resulted in cellhouse operating conditions giving greater operator comfort, while also achieving higher operational efficiency. Source

Elkington T.,Snowden Mining Industry Consultants | Prott R.,University of Western Australia
Mining Engineering | Year: 2013

Mine planners must select a single pit for design with the knowledge that the grades on which this selection is made are uncertain. This uncertainty is often ignored through the use of deterministic models of grade. This makes the mine planner's job simpler but does not necessarily lead to the "correct" or "best" selection. Grade uncertainty is typically modeled with conditional simulation, which generates multiple possible realizations of grade that are equally probable (or improbable). Methods for incorporating grade uncertainty into mine planning to date have either been perceived as being too complicated, not accessible or too time-consuming. This paper proposes a simple and efficient modeling approach to incorporating conditional simulation into pit optimization, which would be able to be applied in currently commercially available software. An example for Resolute Mining Ltd.'s Syama gold project in Mali shows the range of ore, grade and value outcomes associated with generating pits through a variety of methods. Source

Myers P.,Evraz Group | Elkington T.,Snowden Mining Industry Consultants | Elkington T.,University of Western Australia | Wonday S.,Sierra Rutile Ltd
Australasian Institute of Mining and Metallurgy Publication Series | Year: 2012

Sierra Rutile Limited's (SRL) heavy mineral sand mining operation in Sierra Leone, West Africa, is embarking on a new phase of its life. After confronting many challenges during the 1990s and 2000s, SRL is embarking on a strategy of growth to recover maximum value from the mine over the rest of its life. Sophisticated linear programming techniques have been used to develop an optimum strategy for extracting SRL's many known deposits of economic grade, while considering options for expansion and for a variety of mining and processing methods and combinations. Source

Su B.,CAS Institute of Geology and Geophysics | Su B.,University of Chinese Academy of Sciences | Zhang H.,CAS Institute of Geology and Geophysics | Tang Y.,CAS Institute of Geology and Geophysics | And 4 more authors.
International Journal of Earth Sciences | Year: 2011

Garnet-bearing mantle peridotites, occurring as either xenoliths in volcanic rocks or lenses/massifs in high-pressure and ultrahigh-pressure terrenes within orogens, preserve a record of deep lithospheric mantle processes. The garnet peridotite xenoliths record chemical equilibrium conditions of garnet-bearing mineral assemblage at temperatures (T) ranging from ~700 to 1,400°C and pressures (P) > 1.6-8.9 GPa, corresponding to depths of ~52-270 km. A characteristic mineral paragenesis includes Cr-bearing pyropic garnet (64-86 mol% pyrope; 0-10 wt% Cr2O3), Cr-rich diopside (0.5-3.5 wt% Cr2O3), Al-poor orthopyroxene (0-5 wt% Al2O3), high-Cr spinel (Cr/(Cr + Al) × 100 atomic ratio = 2-86) and olivine (88-94 mol% forsterite). In some cases, partial melting, re-equilibration involving garnet-breakdown, deformation, and mantle metasomatism by kimberlitic and/or carbonatitic melt percolations are documented. Isotope model ages of Archean and Proterozoic are ubiquitous, but Phanerozoic model ages are less common. In contrast, the orogenic peridotites were subjected to ultrahigh-pressure (UHP) metamorphism at temperature ranging from ~700 to 950°C and pressure >3.5-5.0 GPa, corresponding to depths of >110-150 km. The petrologic comparisons between 231 garnet peridotite xenoliths and 198 orogenic garnet peridotites revealed that (1) bulk-rock REE (rare earth element) concentrations in xenoliths are relatively high, (2) clinopyroxene and garnet in orogenic garnet peridotites show a highly fractionated REE pattern and Ce-negative anomaly, respectively, (3) Fo contents of olivines for off-cratonic xenolith are in turn lower than those of orogenic garnet and cratonic xenolith but mg-number of garnet for orogenic is less than that of off-cratonic and on-cratonic xenolith, (4) Al2O3, Cr2O3, CaO and Cr# of pyroxenes and chemical compositions of whole rocks are very different between these garnet peridotites, (5) orogenic garnet peridotites are characterized by low T and high P, off-cratonic by high T and low P, and cratonic by medium T and high P and (6) garnet peridotite xenoliths are of Archean or Proterozoic origin, whereas most of orogenic garnet peridotites are of Phanerozoic origin. Taking account of tectonic settings, a new orogenic garnet peridotite exhumation model, crust-mantle material mixing process, is proposed. The composition of lithospheric mantle is additionally constrained by comparisons and compiling of the off-cratonic, on-cratonic and orogenic garnet peridotite. © 2010 Springer-Verlag. Source

Rondon O.,Snowden Mining Industry Consultants
Mathematical Geosciences | Year: 2012

Multivariate conditional simulation is used to assess the multivariate grade risk in mineral deposits. With the presence of several spatially correlated attributes, it is important to ensure that their joint simulation is carried out properly and that the observed spatial correlation is reproduced in the realizations. The method of minimum/maximum autocorrelation factors (MAF) is a well established and practical technique that can be used for this purpose. MAF offers tremendous advantages over standard full cosimulation, principal component analysis, and stepwise techniques. In what follows, a detailed review of the MAF technique, its applications, and examples are provided to guide the practitioner on its use. © 2011 International Association for Mathematical Geosciences. Source

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