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Wong J.C.,Center for Exploration Targeting | Holden E.-J.,Center for Exploration Targeting | Kovesi P.,Center for Exploration Targeting | McCuaig T.C.,Center for Exploration Targeting | Hronsky J.,Western Mining Services Australia Pty Ltd
Exploration Geophysics | Year: 2013

Undercover mineral exploration is a challenging task as it requires understanding of subsurface geology by relying heavily on remotely sensed (i.e. geophysical) data. Cost-effective exploration is essential in order to increase the chance of success using finite budgets. This requires effective decision-making in both the process of selecting the optimum data collection methods and in the process of achieving accuracy during subsequent interpretation. Traditionally, developing the skills, behaviour and practices of exploration decision-making requires many years of experience through working on exploration projects under various geological settings, commodities and levels of available resources. This implies long periods of sub-optimal exploration decision-making, before the necessary experience has been successfully obtained. To address this critical industry issue, our ongoing research focuses on the development of the unique and novel e-learning environment, exSim, which simulates exploration scenarios where users can test their strategies and learn the consequences of their choices. This simulator provides an engaging platform for self-learning and experimentation in exploration decision strategies, providing a means to build experience more effectively. The exSim environment also provides a unique platform on which numerous scenarios and situations (e.g. deposit styles) can be simulated, potentially allowing the user to become virtually familiarised with a broader scope of exploration practices. Harnessing the power of computer simulation, visualisation and an intuitive graphical user interface, the simulator provides a way to assess the user's exploration decisions and subsequent interpretations. In this paper, we present the prototype functionalities in exSim including: simulation of geophysical surveys, follow-up drill testing and interpretation assistive tools. © ASEG 2013.

Groves D.I.,Center for Exploration Targeting | Groves D.I.,China University of Geosciences | Santosh M.,China University of Geosciences | Santosh M.,University of Adelaide | Santosh M.,Kochi University
Geoscience Frontiers | Year: 2015

Discovery rates for all metals, including gold, are declining, the cost per significant discovery is increasing sharply, and the economic situation of the industry is one of low base rate. The current hierarchical structure of the exploration and mining industry makes this situation difficult to redress. Economic geologists can do little to influence the required changes to the overall structure and philosophy of an industry driven by business rather than geological principles. However, it should be possible to follow the lead of the oil industry and improve the success rate of greenfield exploration, necessary for the next group of lower-exploration-spend significant mineral deposit discoveries. Here we promote the concept that mineral explorers need to carefully consider the scale at which their exploration targets are viewed. It is necessary to carefully assess the potential of drill targets in terms of terrane to province to district scale, rather than deposit scale, where most current economic geology research and conceptual thinking is concentrated. If orogenic, IRGD, Carlin-style and IOCG gold-rich systems are viewed at the deposit scale, they appear quite different in terms of conventionally adopted research parameters. However, recent models for these deposit styles show increasingly similar source-region parameters when viewed at the lithosphere scale, suggesting common tectonic settings. It is only by assessing individual targets in their tectonic context that they can be more reliably ranked in terms of potential to provide a significant drill discovery. Targets adjacent to craton margins, other lithosphere boundaries, and suture zones are clearly favoured for all of these gold deposit styles, and such exploration could lead to incidental discovery of major deposits of other metals sited along the same tectonic boundaries. © 2015 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.

Miller J.,Center for Exploration Targeting | Blewett R.,Geoscience Australia | Tunjic J.,St Ives Gold Mining Co | Connors K.,FrOG Technology
Precambrian Research | Year: 2010

A revised structural interpretation for the Victory to Kambalda area of the world class St Ives Goldfield in the Archean Yilgarn Craton has mapped out the distribution of WNW-trending faults within this area of the field. These previously cryptic WNW-trending structures had been identified in gravity data, and also by isopach thickness variations. The WNW-trending faults acted as transfers syn-gold mineralization, although only discrete segments of these faults were active during the main stage of gold mineralization. Where mineralized, the faults transferred strain from a complex combination of block-on-block movement associated with thrusting and strike-slip movement on NW- and N-trending faults. Along some segments N-trending mineralized faults terminate against the WNW-trending faults. Many of the WNW-trending faults correlate with major strike changes on regional and camp-scale faults and they are domain boundaries for the critical N-trending fault segments that host high-grade gold within contractional jogs. The WNW-trending faults also show evidence for an older deformation history prior to main-stage gold, which may extend back to early basin development associated with ultramafic and mafic volcanism. They are inferred to have been a series of early WNW-trending normal faults and breached relay ramps associated with oblique rifting along an older NNW-trending basement boundary. © 2010.

Lu Y.-J.,Center for Exploration Targeting | Lu Y.-J.,Chinese Academy of Geological Sciences | Kerrich R.,Center for Exploration Targeting | Kerrich R.,University of Saskatchewan | And 14 more authors.
Economic Geology | Year: 2013

The Yao'an porphyry Au system, Machangqing porphyry Cu-Mo system, and Beiya porphyry-skarn Au system, are spatially and temporally associated with potassic felsic intrusions emplaced during the Eocene to Oligocene epochs at 37 to 33 Ma in a postcollisional intracontinental setting in western Yunnan, western Yangtze craton, China. The Yao'an monzonite and quartz monzonite porphyry intrusions are alkaline and potassic with high K2O/ Na2O ratios (1.1-1.5). They have Sr-Nd-Pb isotopes similar to coeval lamprophyres and are characterized by uniform zircon εHf (-6.4 to -8.7) and δ18O values (6.6-7.0‰). They are interpreted as products of fractional crystallization of lamprophyre-like potassic mafic magma derived from ancient metasomatized lithospheric mantle, a scenario similar to the mid-Cretaceous postcollisonal Scheelite Dome gold system in Yukon, Canada. The Machangqing granitic intrusions are high K calc-alkaline and show high Sr, Sr/Y, and La/Yb, but low Y and Yb geochemical signatures. They have Sr-Nd-Pb isotope compositions similar to amphibolite xenoliths hosted by potassic felsic intrusions in western Yunnan. The zircon εHf values of the Machangqing granitic intrusions are positive (0.3-4.7), and the zircon-depleted Hf mantle model ages are 1.1 to 0.8 Ga. They also have mantle-like zircon δ18O values (5.5-6.4‰). The Machangqing granites were most likely derived from partial melting of Neoproterozoic lower crust. The Beiya granitic intrusions are alkaline, with high K2O/Na2O (1.9-2.7), Sr/Y and La/Yb ratios, high Sr contents, and low Y and Yb contents. They contain abundant zircon inheritance and have variable magmatic zircon εHf (-4 to +4) and the highest magmatic zircon δ18O values (6.6-7.8‰). The Beiya felsic intrusions are interpreted to be derived from partial melting of a K-rich mafic source mixed with a metasedimentary component. The Eocene-Oligocene intracontinental potassic intrusions and associated mineralization in western Yunnan are located proximal to the Mesozoic Jinsha suture, suggesting that this Mesozoic lithospheric boundary may have provided a first-order control on localization of Cenozoic mineral systems. These potassic felsic intrusions are coeval with regional potassic mafic magmatism in western Yunnan and were emplaced between 37 to 33 Ma, after the collision between India and Asia at ca. 60 to 55 Ma. It is therefore postulated that continental collision may have preferentially thickened the continental lithospheric mantle (CLM) adjacent to the Jinsha suture, in which overthickened lower continental lithospheric mantle was subsequently removed during 37 to 33 Ma, inducing melting of residual metasomatized lithospheric mantle as well as lower crust. The gold-rich Yao'an and Beiya intrusions are alkaline and potassic, characterized by high zircon δ18O values (>6.5‰), which is consistent with supracrustal contributions. In contrast, the Cu-Mo-rich Machangqing intrusions are high K calc-alkaline with mantle-like zircon δ18O values (<6.5‰) and juvenile εHf signatures, indicating negligible supracrustal recycling. Empirically, source compositions played an important role in determing the metal endowment among intrusions formed under the same tectonic setting with similar ages in western Yunnan. In western Yunnan, gold tends to be associated with alkaline and potassic melts with a supracrustal contribution, whereas Cu-Mo mineralization seems to be more related with juvenile crustal sources with little supracrustal influence. © 2013 Society of Economic Geologists, Inc.

ShahNazari M.,Murdoch University | McHugh A.,Murdoch University | Maybee B.,Economy Energy | Maybee B.,Center for Exploration Targeting | Whale J.,Murdoch University
Applied Energy | Year: 2014

Political uncertainty over global greenhouse gas (GHG) mitigation policy is likely to defer investment in cleaner technologies. It may also incentivise short-lived, high-cost interim investments while businesses wait for the uncertainty to subside. The range of possible policy responses to the issue has created uncertainty over the future of national mitigation pathways. Given that the electricity sector, globally, is a major emitter of GHGs, this represents a systematic risk to investment in electricity generation assets. This paper uses a real options analysis framework informed by a survey of experts conducted in Australia - used as a proxy to model the degree of the uncertainty - to investigate the optimal timing for investment in the conversion of a coal plant to a combined cycle gas turbine plant using the American-style option valuation method. The effect of market and political uncertainty is studied for the Clean Energy Act 2011 in Australia. Political uncertainty is addressed bi-modally in terms of: (1) uncertainty over the repeal of the carbon pricing policy, and (2) if it is repealed, uncertainty over the reinstatement of the policy, to represent the effect of electoral cycles and the possibility of more stringent future global mitigation efforts. Results of the analysis show that although political uncertainty with respect to GHG mitigation policy may delay investment in the conversion of the coal plant, expectations over the reinstatement of the carbon pricing reduces the amount of option premium to defer the conversion decision. © 2014 Elsevier Ltd.

Nazari M.S.,Murdoch University | Maybee B.,Economy Energy | Maybee B.,Center for Exploration Targeting | Whale J.,Murdoch University | McHugh A.,Ernst And Young
Energy Procedia | Year: 2015

A decision support framework has been provided to assist investors with long-term decision-making for investment choices in power generation assets under uncertain climate policy. The model combines real options analysis and modern portfolio optimization theory. A long-term correlation between carbon and renewable portfolio standard certificate prices is used to model the interaction of climate policies, with a case study being developed to investigate the optimal choice of capacity additions to an existing mix of power generation assets in Australia. The findings show that there is potential for investors to fully hedge their existing fossil fuel based generation assets through the addition of on-shore wind capacity. The model developed allows for (1) the investigation of investment risk and return under uncertain climate policies, and (2) the study of interaction among green policies. © 2015 Published by Elsevier Ltd.

Rouillard A.,University of Western Australia | Greenwood P.F.,University of Western Australia | Greenwood P.F.,Center for Exploration Targeting | Greenwood P.F.,Curtin University Australia | And 5 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2016

Detection of source diagnostic molecular fossils (biomarkers) within sediments can provide valuable insights into the vegetation and climates of past environments. However, hot and arid regions offer particularly challenging interpretive frameworks for reconstructions because baseline data are scarce, organic matter is generally very low and in the inland tropics in particular, sediments are also often subject to flooding and drought. Here, we investigated whether biomarkers and compound-specific δ13C values could be extracted from a late Holocene sediment record from the Fortescue Marsh (Pilbara, northwest Australia) to allow interpretation of past catchment vegetation and hydroclimate. The low total carbon (TC) content (< 1.4%) was a major challenge for the molecular analyses over the ~ 2000 years old sequence. Nevertheless, they revealed that the dominant hydrocarbon features (e.g., long chain n-alkanes) indicative of terrestrial plants (e.g., C4 grasses; riparian and other C3 plants) encompassed the last ~ 1300 yrs and that low abundance of products from aquatic sources (e.g., n-C17) were detected in the uppermost sediments only when permanently inundated conditions prevailed (recent decades). Similarly, the lower δ13C values (i.e., a difference of − 2.3‰) of long chain n-alkanes in upper sediments reflected a vegetation response to the emergence of wetter conditions through the late Holocene in the region. Based on the diverging dominant source contributions obtained from the molecular distributions and arid based Bayesian mixing model (δ13C of n-C27–33 alkanes) results, less arid conditions may have favoured the input of 13C depleted n-alkanes from the Eucalyptus (C3) dominant riparian vegetation. The deepest sediments (< 700 CE) however, had a TC content of < 0.4%, and no organic compounds were detected, consistent with local and regional records of hyperarid conditions. These results demonstrate that n-alkanes can provide a molecular and stable isotopic fingerprint of important - and perhaps underappreciated - ecological processes in modern tropical arid environments for future paleoclimate investigations. © 2016 Elsevier B.V.

Shahnazari M.,University of Western Australia | McHugh A.,University of Western Australia | Maybee B.,Economy Energy | Maybee B.,Center for Exploration Targeting | Whale J.,University of Western Australia
Applied Energy | Year: 2014

Greenhouse gas (GHG) intensive fuels are currently a major input into the Australian electricity sector. Accordingly, climate change mitigation policies represent a systematic risk to investment in electricity generation assets. Although the Australian government introduced carbon pricing in 2012 and announced a commitment to the continuation of the Kyoto protocol beyond 2012, the opposition at the time signalled that should they be provided the opportunity they would repeal these policies. This paper uses a real options analysis (ROA) framework to investigate the optimal timing of one potential business response to carbon pricing: investment in the conversion of coal plant to lower emission CCGT plant. An American-style option valuation method is used for this purpose. The viewpoint is from that of a private investor assessing three available options for an existing coal plant: (1) to invest in its conversion to CCGT; (2) to abandon it, or; (3) to take no immediate action. The method provides a decision criterion that informs the investor whether or not to delay the investment. The effect of market and political uncertainty is studied for both the Clean Energy Act 2011 (CEA) and high carbon price (HCP) policy scenarios. The results of the modelling suggest that political uncertainty after the implementation of carbon pricing impedes the decision to switch to cleaner technologies. However, this effect can be mitigated by implementing higher expected carbon prices. © 2014 Elsevier Ltd.

Gallardo L.A.,CICESE | Gallardo L.A.,Center for Exploration Targeting | Fontes S.L.,Observatorio Nacional ON MCT | Meju M.A.,Petronas | And 3 more authors.
Geophysics | Year: 2012

We have applied a crossgradient joint inversion and geospectral visualization method to marine seismic reflection, magnetotelluric, gravity, and magnetic data sets acquired along a 162 km profile across a segment of Santos Basin oil province in the continental margin of southeast Brazil. The main exploration targets are the top of the fractured Precambrian crystalline basement and any concealed basement grabens, the overlying presalt and salt/carbonate deposits, and the postsalt cover deposits. The results of joint inversion clearly mapped the various units and are a significant improvement over previous models derived from separate 2D seismic reflection processing and 2D magnetotelluric imaging. Additionally, multispectral fusion of these models resulted in a single image that permits highly constrained geologic interpretations enabling a better understanding of basin architecture. We suggest that joint inversion and image fusion is the way forward for effective geophysical integration. © 2012 Society of Exploration Geophysicists.

Bell J.A.,Center for Exploration Targeting | Bell J.A.,Alexander Research | Guj P.,Center for Exploration Targeting | Havlin S.R.,Optiro | Glacken I.M.,Optiro
AusIMM Bulletin | Year: 2010

The value associated with the confidence level in mineral resource estimates can be gauged, in the case of gold deposits, by spatially distributing their sales prices of as a function of their sizes, grades and resources confidence index. The sale prices of 300 gold deposits in Australia, Canada and the United States reflect the expectation that, at some stage they may support a profitable mining operation and the magnitude of its potential future cash flows. The sales price is a function of the size (Moz) of the deposit, its gold grade equivalent (g/t Au), the mineral estimate certainty, scale and type of possible operation and its likely capital and operating costs. The dynamic relationship between these parameters is used in a 3D block-model to predict prices for future transactions in these safe, mature mining jurisdictions given any size, grade and estimate confidence combination. While this study confirms that transaction unit values generally rise with increases in size and grade, the main finding is that an increase in confidence does not necessarily always translate into an increase in value if the deposit is perceived to be 'small'. The blockmodel method adopted in this study has the potential to inject some comparability and objectivity in the otherwise arbitrary application of 'ruleof-thumb' in determining transaction prices for in situ resources, which may contain various classifications of ore reserves and mineral resources as well as other less formal mineral estimate classifications, helping project managers optimise exploration expenditure.

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