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Gerrards Cross, United Kingdom

Leslie K.,University of Kansas | Oates C.J.,Applied Geochemical Solutions | Kyser T.K.,Queens University | Fowle D.A.,University of Kansas
Geochemistry: Exploration, Environment, Analysis

An economic Cu-Zn volcanogenic massive sulphide (VMS) deposit was modeled in flow-through columns to examine the microbial controls on ore weathering and soil anomaly development. The presence of microorganisms, especially S- and Fe-oxidizing bacteria, increased the rate of weathering and metal release from ore. To examine the development of soil metal anomalies overlying the VMS deposit, flow-through experiments modeling the full overburden profile were completed. Selective extractions on the soil demonstrated that enhanced metal anomalies in the biotic column were developing in the reactive Fe- and Mn- oxide phases. These experimental results are linked to in situ biogeochemical processes through the use of Fe-oxidizing bacteria isolated from the deep subsurface of Triple 7 Cu-Zn VMS mine in Flin Flon, Manitoba, Canada, in direct proximity to where the ore material was collected. These results demonstrate that the rates of metal mobility in the subsurface and soil metal anomaly development at the surface are increased by the presence and activity of microorganisms when compared to control experiments. © 2014 AAG/The Geological Society of London. Source

Leslie K.,University of Kansas | Sturm A.,University of Kansas | Stotler R.,University of Kansas | Oates C.J.,Applied Geochemical Solutions | And 2 more authors.
Geochemistry: Exploration, Environment, Analysis

A microorganism of the Marinobacter genus capable of Fe-oxidation at near-neutral pH, both in the presence and absence of oxygen, was found at a depth of 1.4 km in proximity to a Cu-Zn Volcanogenic Massive Sulphide (VMS) deposit, within the Triple 7 mine, Flin Flon, Manitoba, Canada. The microorganism was isolated from saline groundwater emanating from boreholes at that depth, which contained a small microbial community consisting of only two organisms. To examine biogeochemical trace metal cycling in this deep subsurface setting, incubation experiments were carried out with the Marinobacter isolate and mineralized (metal-containing ore) material in batch and column flow-through settings. The activity of the Marinobacter isolate resulted in an increase in the mobilization of major elements (Fe, S) and trace metals (Cu, Zn) from the solid ore material. These results indicate that Fe-oxidation may be an important biogeochemical process in the deep subsurface, which affects the mobilization of Fe and trace elements from buried mineralization. © 2015 The Author(s). Source

Leslie K.,University of Kansas | van Geffen P.W.G.,Queens University | MacFarlane B.,Queens University | Oates C.J.,Applied Geochemical Solutions | And 2 more authors.
Applied Geochemistry

Results are presented of a surficial geomicrobiological investigation of glacial cover overlying buried mineralization at the Talbot prospect, Manitoba, Canada, where previous surficial geochemistry surveys indicated anomalous concentrations of elements above the buried mineralization. The Cu-Zn volcanogenic massive sulfide (VMS) occurrence is overlain by 100. m of Paleozoic dolomites and Quaternary glacial cover. The geomicrobiological investigation demonstrates that there is a distinct microbial ecology at the anomalous sampling locations, especially directly overlying buried mineralization. The combined geochemical and geomicrobiological analyses reveal the presence of an anomaly directly over mineralization due to oxidation of the buried ore. Specifically, geomicrobiological analyses yield an inverse correlation between Zn in the clay-size (<2. μm) fraction and total microbial biomass and a direct correlation between Cu in the clay-size (<2. μm) fraction and abundance of methanotrophic bacteria. These results demonstrate that microbiological analyses can be a useful addition to geochemical exploration by revealing metal transport and sequestration processes and enhancing surficial anomalies. © 2013 Elsevier Ltd. Source

Masquelin A.-S.,Queens University | Kaveh F.,Queens University | Asfaw A.,Queens University | Oates C.J.,Applied Geochemical Solutions | Beauchemin D.,Queens University
Geochemistry: Exploration, Environment, Analysis

A simple and fast method, using solid sampling electrothermal vapourization inductively coupled plasma optical emission spectrometry (ETV-ICP-OES), was developed to determine the distribution of elements in clay separates and soil samples from across the Talbot Lake VMS Cu-Zn prospect, in the Flin Flon-Snow Lake terrane, Manitoba, Canada in order to locate the undercover ore deposit, which is buried under Palaeozoic dolomites and Quaternary till. In the development of the method, the mass of sample, the mass of carrier agent (polytetrafluoroethylene, PTFE) or flow rate of reactant gas (dichlorodifluoromethane (R12)), the carrier and bypass gas flow rates and the temperature program were optimised. Under optimal conditions and with a four-step ETV temperature program, the distribution of the pathfinder elements (Zn, P, S and I) in clay separates and soils showed clear anomalies at 400 and 650 m. The results for Zn and P are in very good agreement with results obtained, following aqua regia (AR) digestion, by ICP mass spectrometry (ICP-MS) by Anglo American Exploration Division (AA-ED). Moreover, the distributions of S and I could be precisely determined (these elements were not reported in the AA-ED study). Using 0-4 mg of AA-ED S5 standard mixed with 2 mg PTFE or with 4.1 ml/min R12 as reactant gas, and using internal standardisation with an argon emission line, calibration curves were obtained that, when applied to Talbot clay separates and soil samples, yielded Zn, S and P concentrations in agreement with AR-ICP-MS results previously obtained by AA-ED. Hence, ETV-ICP-OES completely eliminates the need for clay separation and for extraction or digestion of samples prior to analysis, which significantly simplifies the analysis of geochemical exploration samples. © 2013 AAG/Geological Society of London. Source

Voulvoulis N.,Imperial College London | Skolout J.W.F.,Imperial College London | Oates C.J.,Applied Geochemical Solutions | Plant J.A.,Imperial College London
Environmental Science and Pollution Research

On top of significant improvements and progress made through science and engineering in the last century to increase efficiency and reduce impacts of mining to the environment, risk assessment has an important role to play in further reducing such impacts and preventing and mitigating risks. This paper reflects on how risk assessment can improve planning, monitoring and management in mining and mineral processing operations focusing on the importance of better understanding source-pathway-receptor linkages for all stages of mining. However, in light of the ever-growing consumption and demand for raw materials from mining, the need to manage environmental resources more sustainably is becoming increasingly important. The paper therefore assesses how mining can form an integral part of wider sustainable resources management, with the need for re-assessing the potential of mining in the context of sustainable management of natural capital, and with a renewed focus on its the role from a systems perspective. The need for understanding demand and pressure on resources, followed by appropriate pricing that is inclusive of all environmental costs, with new opportunities for mining in the wastes we generate, is also discussed. Findings demonstrate the need for a life cycle perspective in closing the loop between mining, production, consumption and waste generation as the way forward. © 2013 Springer-Verlag Berlin Heidelberg. Source

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