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Structural Controls and Strain Partitioning in the Red October Gold Mine, Western Australia J G McLellan1,2, J Conn3, D Howe4 and K Gates5 ABSTRACT The Red October Gold Mine, owned by Saracen Gold Mines Pty Ltd, is located approximately 80 km south of Laverton, Western Australia. It is considered to be of a similar nature to many of the Archaean granite-greenstone deposits in the Laverton Tectonic Zone, and presents as an intriguing and relatively young deposit in terms of developed structural and genetic models. Regional deformation events have been proposed for the area, and are relatively well accepted. The most important of these deformation events in the region were the D4b (WNW–ESE sinistral transpression) and D5 (ENE–WSW dextral transpression) which have been attributed to the main Au mineralising phases. At the local scale there appears to have been a rotation of the regional stress field to provide the optimum orientation of maximum principal stress for sinistral movement on the main shear zone. Fully coupled 3D finite element analysis (FEA) was used to simulate the geomechanical response of the system based on structural observations. The geomechanical modelling resulted in highlighting anomalous patterns of stress and strain and subsequent fluid flow as a result of the two main deformation events. The D4 simulation provided a good correlation with the known distribution of subsidiary structures on the main shear zone, and furthermore provided several geomechanical targets that suggested locations of additional subsidiary structures. The D5 simulation provided a great insight into the response of the main shear zone and known subsidiary structures also highlighting additional targets indicating potential for further mineralisation. These targets have since been followed up with a 732 m deep surface reverse circulation (RC) drill hole, resulting in the discovery of two high-grade shoots, with follow up testing currently planned for mid-2014.
INTRODUCTION The Red October Gold Deposit is located within the Laverton Tectonic Zone, of the Western Australian Yilgarn Craton (Figure 1) approximately 80 km south of Laverton, Western Australia. The stratigraphy of the Laverton region is defined broadly by an approximate 2800 Ma mafic-ultramafic succession overlain by a 2715 Ma intermediate volcanic succession. This in turn, is overlain by siliciclastic basin successions and intruded by temporally and chemically distinct suites of felsic to mafic intrusive rocks (Standing, 2008). Blewett and Czarnota (2007), amongst others, have defined the deformational history from the Central Eastern Yilgarn by identifying dominant structures and vectors. The main structural fabric of the region is the result of a protracted deformation history from ~2800 to ~2630 Ma consisting up to at least five main deformation events. The region underwent a couple of extensional events (D1 ) ~2800 to ~2698 Ma, which resulted in the main north-south architecture seen today. This was followed by a NE compressional D2 event around
~2670 Ma and dextral shearing. Granite doming and core complex formation took place during D3 ~2665 to ~2655 Ma, this was followed by two stage D4a and D4b events ~2645 to ~2655 Ma, with NE through to SE compression, resulting in upright folding of the late basins and greenstone sequence. The last significant deformation event was the D5 NE compressive event that resulted in dextral strike slip along N to NE striking faults. These deformation events have also been proposed as the contributors to Au mineralisation at the Sunrise Dam Gold Mine (Blenkinsop et al, 2007; McLellan et al, 2007), which is approximately 12 km to the north of the Red October Deposit. However, there has most likely been a localised rotation of the stress field from north-east to more north-north-east for the maximum principal stress to be at an optimal orientation for sinistral movement on the main structure, the Red October Shear zone. The Red October Deposit sits within Lake Carey and is hosted within an ultramafic-mafic sequence of rocks. There
1. MAusIMM, Managing Director and Principal Geoscientist, GMEX, PO Box 9070, Bluewater Qld 4818. Email:
[email protected] 2. Adjunct Senior Research Fellow, Economic Geology Research Unit, James Cook University. 3. Project Mine Geologist, Saracen Gold Mines Pty Ltd, 89 St Georges Terrace, Perth WA 6000. Email:
[email protected] 4. MAusIMM, Exploration Manager, Saracen Gold Mines Pty Ltd, 89 St Georges Terrace, Perth WA 6000. Email:
[email protected] 5. Project Geologist, Saracen Gold Mines Pty Ltd, 89 St Georges Terrace, Perth WA 6000. Email:
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•• better understand the deformation events with respect to fluid pressure evolution and geomechanics •• use the geomechanical results to predict deep targets for within mine exploration.
GEOMECHANICS AND FLUIDS Modelling the coupled geomechanical and the fluid flow response to deformation events in rocks has proven a very useful technique in simulating mineralising systems (McLellan, Oliver and Schaubs, 2004; Schaubs et al, 2006; McLellan et al, 2007, 2014; Nugus et al, 2014). The basic concept in this modelling technique is to simulate the most likely deformation response by highlighting the partitioning of stress, strain and fluid pressure in the rocks which can ultimately lead to much better predictive targeting in structurally controlled systems. The underlying constitutive relationships include a Mohr-Coulomb failure criteria and the coupling of fluid flow to this constitutive model. The classical Mohr-Coulomb material with non-associated plasticity is best suited to represent the rheology of mid-to-upper crustal rocks (Vermeer and de Borst, 1984; Hobbs, Muhlhaus and Ord, 1990). A Mohr-Coulomb material will undergo deformation elastically up to a yield point and then deform in a nonrecoverable plastic manner (Figure 2): |τs| = c – σn tan z (1) where: τs and σn are the shear and normal stresses across arbitrary planes within a material c and z are material constants (cohesion and friction angle respectively) During plastic deformation a Mohr-Coulomb material will shear, and this can be associated with dilation or a volume change. The microstructural processes involved have been highlighted by Vermeer and de Borst (1984), Ord and Oliver (1997), and more recently by Gow et al (2002). During deformation rocks can compact and dilate, therefore dilation can be represented by both positive and negative values of strain: sin ψ = εpv/γp (2)
FIG 1 – Simplified geological map of the Lake Carey region, indicating the location of Red October and other local deposits (Graham, 2003).
where:
is a minor shale rich unit apparent on a north-east trending contact within the sequence and this is the main host to the currently known mineralised zones. The main north-east orientated mineralised shear zone is located on the northwestern limb of a tight isoclinal fold, which appears to buttress a felsic intrusion to both the west and north-west of the deposit. The main mineralised zones are located not only within this north-east trending shear zone but within fault intersections and several subsidiary structures. In the Laverton Tectonic Zone, structure is an important aspect of the geology that ultimately controls mineralisation. Not only is there a need to better understand the structures, rock material, and its deformation response, but also the interaction between the deformation and fluid pressure evolution which ultimately drives fluid migration through the system. Here we use coupled geomechanical and fluid flow modelling to better understand this system, and to use it in a predictive capacity for targeting mineralisation extensions in the Red October Gold Deposit. The aims of this study were to: 316
FIG 2 – An elastic-perfectly-plastic stress strain curve. White and black arrows represent loading and unloading cycles respectively. Once loading occurs the stress value reaches a critical point where unrecoverable plastic strain takes place.
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STRUCTURAL CONTROLS AND STRAIN PARTITIONING IN THE RED OCTOBER GOLD MINE, WESTERN AUSTRALIA
ψ is the dilation angle εpv is the rate of plastic volumetric strain is the rate of plastic shear strain γp Local positive dilation is crucial in deforming porous media as it typically influences fluid flow direction more abruptly than the gentle gradients associated with topography or broadly distributed strains. For a more comprehensive explanation see Vermeer and de Borst (1984). The movement of crustal fluids occurs as a response to head gradients and buoyancy forces. Hydraulic head (H) is a measure of mechanical energy per unit weight of fluid, equivalent to the height above an arbitrary datum, eg sea level, to which fluid will rise in a well. The simplest form of equation describing hydraulic head is an elevation and pressure term: H = z + P/ρg
(3)
where: is the hydraulic head H z is the elevation above a datum P is the pore fluid pressure is the density of the fluid ρ g is the acceleration due to gravity The governing equation determining fluid flow in a porous media can be expressed by Darcy’s Law: Vi = kij
c f 2H (4) hf c 2xj m
where: is the Darcy fluid velocity (ms-1) Vi kij is the permeability tensor (m2) is the specific weight (kg m-2 s-2) γf is the viscosity (kg m-1 s-1) of the fluid ηf is the hydraulic head (P/ρg + z) (m) H is the position of a material point xj Darcy’s Law shows that differences in hydraulic head are required for flow to occur, and a static homogenous rock package with topographic relief displays classical Darcian flow as a result of these head gradients. Darcy fluid flow vectors are by definition orthogonal to contours of hydraulic head in an isotropic medium with a constant density. However, in a fluid saturated porous media that is deforming, effective stress is generally changing. Instantaneous changes in pore pressure (and hence effective stress) will result from local changes in total stress, but fluid flow is not instantaneous as it is governed by Darcy’s Law. The fluid accommodates these changes in total stress, and the system responds by outward flow from regions of high or increased total stress, with the material deforming elastically and plastically as the fluid migrates away. Our structural analysis relies on a ‘poroplasticity’ model, and hence fluid will focus in areas of failure (at yield in shear or tension) within the model. The model material properties (including dilation angle), when subjected to stress, influence an ‘elasto-plastic’ volume change. This is related to and influenced by pore pressure at that point, and the implicit link to flow is via the pore pressure and hydraulic head (gravitational) parts of Darcy’s Law. Thus there is a ‘pseudo’ porosity change at each step, which is manifest in the numerical calculations as a volume change (positive or negative dilation). This differs from models in which fluid pressure changes are purely a ‘poro-elastic’ response to applied stress. Effective stress is thus not an imposed variable, but one which is calculated for every step in every
zone within the model during its cycle. The emphasis of much early work in this field (eg Ge and Garven, 1992) has been focused on the elastic part of stress-strain behaviour (the poro-elastic effect) and has concentrated on the generation of regions of high pore pressures due to elastic decrease in total volume by an imposed stress. This typically results in fluid being ‘squeezed’ out of the stressed regions. In contrast, in poro-plastic models high strain typically causes positive dilation of rocks and pore pressure decrease, and hence fluid is drawn in. Changes in volume due to plastic deformation are governed by the dilation angle of the rocks (ψ), and these changes in volume result in changes in pore pressure (Ord, 1991; Ord and Oliver, 1997). This effect on pore pressure is linked to changes in hydraulic head, which drives fluid flow, in accordance with Darcy’s Law. Therefore, volume change is related to changes in effective stress, which can lead to further plastic deformation, which feeds back to more volume change. This feedback between deformation and fluid flow continues in a coupled manner.
STRUCTURAL AND CONCEPTUAL MODELS The Red October Deposit is located along the contact of a basaltultramafic sequence, defined by shear mineralised shale with a varying thickness of 0.5 m to 5 m wide, dependent upon silica alteration (Figure 3). This is the main mineralisation horizon, and is mostly striking NNE (045°). Subsidiary structures (Smurf and Smurfette) are located within the footwall basalts at Red October, defined by ductile shearing of quartz-biotitesericite alteration, striking at approximately NNW (350°). The Smurf/Smurfette structures have a dip-dip direction of 40° to 040°; however they steepen to approximately 60°as they interact with the Red October Shale horizon. Less economic Krill structures are also observed as subsidiary structures in the footwall basalt, however they only appear towards the southern extents of the deposit, and tend to have a steeper geometry (60° to 040°). The Krill structures are defined by a quartz-sericite-biotite shear zone; however they exhibit weaker alteration and sulfide mineralisation in comparison to the Smurf and Smurfette structures. The dominant gold bearing subsidiary structure is the Marlin lode, which is located in the footwall. The Marlin lode is defined by brecciated quartz-pyrite-gold mineralisation with an alteration selvage defined by sericite and pyrite. In the upper levels of the mine (less than 200 m depth), the Marlin lode is located along the contact against the Red October Shear zone, overprinting in some areas, giving the shale a silica-flooded appearance. This is where the mineralised zone and gold bearing zones are thickest in the deposit. Deeper in the system the Marlin lode splits off from the shale contact, and shows a flat intersection lineation of 10° plunging south (Figure 4). Underground mapping has uncovered three main styles of mineralisation, which are defined by the Smurf and Marlin footwall subsidiary structures and the Red October Shear zone. When all three styles are present, it is not uncommon for assayed gold values to return in excess of 500 g/t Au. Initial conceptual modelling of the Red October Deposit was done upon the presumption that the Red October Shear zone was a single, narrow vein style orebody dipping 80° to 315°, located along the contact of the footwall basalts and hanging wall ultramafics. However, drilling has defined numerous subsidiary structures in the footwall of varying alteration and mineralisation styles. Currently, concept modelling of the Red October Shear zone is defined by localised domains within the shear zone of greater than 3 g/t Au. At the deposit scale, each subsidiary structure along with the main Red October
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FIG 3 – Three-dimensional structural view of the Red October Deposit looking north, indicating the main north-east trending Red October shear and several subsidiary structures.
FIG 4 – Structural model of the Red October Deposit showing the relationship between the Marlin lode and Red October Shear zone. The red squares are old pierce points for drilling, yellow arrow defines the plunge of the intersection of the Red October Shear zone and Marlin lode, and where they split at depth. Shear zone is domained, which is dependent upon geological intervals in both drill core and underground development. Due to mining constraints, the Krill and Smurfette subsidiary structures have a limited data set available as there is minimal underground development of these structures. The overall geometry of the main fault zone and its geometrical relationships with the smaller subsidiary structures suggests that these structures are fault-related tensile vein/fracture arrays. These structures would most likely have formed during a left-lateral sinistral movement on the main fault, most likely during the D4b regional event. However, there has most likely been a localised rotation of the stress field from NE to more NNE to be at an optimal orientation for sinistral movement on the main structure. There is also evidence of reverse dextral movement on the subsidiary structures (Figure 5), and this is most likely due to the later D5 event, and has been reported as being a locally intense deformation event in the region. The apparent folding in the main structure (eg major inflections and the North Bend Region (purple colours in Figure 3)) also suggests dextral movement as being later and potentially responsible for the mineralisation of the pre-existing structures. A conceptual model based upon mine DXF files (Figure 6) with dimensions of approximately 1.7 km × 1.6 km × 1 km was built using the existing 3D information from the Saracen database, and two 3D solid models were constructed incorporating the main fault and the lithological components of the mine area (Figure 6). These models were used as the starting point for complex meshing to enable coupled geomechanical and fluid flow simulations of the two main deformation events thought to be responsible for the 318
architecture set-up and focusing of fluids resulting in Au mineralisation. Model 1 consisted of the main shear zone, the Marlin and mafic structures and was testing the earlier sinistral movement on the main shear. Model 2 also consisted of the later formed subsidiary structures and was testing the later reverse dextral movement. Model boundary conditions were commensurate with a D4 NW–NNW compression and a D5 SSE compression.
RESULTS Model 1 – north-west to north-north-west compression At early stages of the deformation we can see the distribution and intensity of both shear strain rates and increments matching well with the locations of the subsidiary structures (Figure 7). This localisation of strain during the main sinistral movement on the main shear zone also highlights northerly dipping trends. As deformation progresses we continue to see the partitioning of strain on fault inflections and undulations, with greatest changes of shear strain increments noted around the subsidiary structure locations and at depth (Figure 8). Volumetric strain rates also show highest values in and around subsidiary structures and match well with known structural orientations (Figure 8).
Model 2 – south-east compression The SSE deformation event of Model 2 forms large scale conjugate patterns that vary in position through the evolution of the system. The main structures that are potentially
NINTH INTERNATIONAL MINING GEOLOGY CONFERENCE / ADELAIDE, SA, 18–20 AUGUST 2014
STRUCTURAL CONTROLS AND STRAIN PARTITIONING IN THE RED OCTOBER GOLD MINE, WESTERN AUSTRALIA
FIG 5 – A series of shear sense indicators illustrated on photographs of underground relationships on the subsidiary structures. Note the right lateral sense on the sigmoidal quartz, quartz veins and sheared sulfide layers.
A
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FIG 6 – (A) Solid geology model of the Red October Deposit Model 1, looking north-west with Mafic unit 1 transparent for viewing purposes. Note: the dxf surfaces of the main structural lodes in the mine have been added for reference. (B) Model 2 geometry; solid geology model displaying the main fault, and tensile fault arrays. Mafic unit 1 is again transparent for viewing purposes reactivated are the Smurf, Smurfette, Krill structures and in particular the area around the Nemo structure which sits within a high strain zone for the majority of the deformation event (Figure 9). The Marlin Fault is also affected by areas of high strain and volumetric increase or dilation. Also noted are undulations on the main fault structure, which if host tensile fracture arrays could potentially be zones of
FIG 7 – Model 1 contours of maximum values of (A) shear strain rates and (B) shear strain increments on the main fault surface looking approximately north-west. high-grade mineralisation. Such areas include behind the Marlin breakaway structure and below the North Bend. As deformation progresses we see prominent large scale conjugate structures start to form (Figure 10), and these similar
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A
B
FIG 10 – Model 2 contours of maximum shear strain rates looking approximately south-west. Note the conjugate pattern focused over the Smurfette and the Krill structures. patterns can be seen emerging from grade block distributions (see Figure 13).
Results summary
FIG 8 – Model 1 contours of maximum values of (A) shear strain increments and (B) volumetric strain rates on the main fault surface looking approximately north-west. Note the correlation between highest values and subsidiary structures.
A
The progression of stages during Model 1 (NW and NNW compression models) displays an overall correlation with the known fault related tensile arrays. At early stages we recognise the partitioning of stress and strain into discrete areas that correspond to ridges and inflections on the main fault surface which corresponds well to the locations of the subsidiary structures. Maximum shear strain rates and volumetric strain increments are localised particularly well around inflections on all surfaces, and also at depth. These areas are probably a good indication of preconditioning of the architecture for later mineralising fluids. Late stages of Model 1 tend to show a broader scale pattern of shear trends and may not be as good an indicator for the location of further subsidiary structures as the earlier stages, however they should not be dismissed. Model 1 has shown there is good potential for finding further subsidiary structures related to sinistral movement on the main fault system. These areas are mostly at depth below the currently known architecture and are highlighted as potential targets in the targeting and validation section of this article. The SSE deformation event of Model 2 forms large scale conjugate patterns that vary in position through the evolution of the system. The main structures that are potentially reactivated are the Smurf, Smurfette, Krill structures and in particular the area around the Nemo structure which sits within a high strain zone for the majority of the deformation event. The Marlin Fault is also affected by areas of high strain and volumetric increase or dilation. Also noted are undulations on the main fault structure, which if host tensile fracture arrays could potentially be zones of highgrade mineralisation. Such areas include behind the Marlin breakaway structure and below the North Bend.
B
GEOMECHANICAL TARGETING AND VALIDATION
FIG 9 – Model 2 contours of (A) volumetric strain increments and (B) shear strain increments looking approximately south-west. Note the correlation of the Nemo fault (red), Smurf Fault and higher values below the North Bend and at depth on the Marlin Fault. 320
The results from the geomechanical modelling have highlighted several areas that are more structurally favourable for mineralisation (Figure 11). These areas include the Shale Deeps target, explained in the following paragraph, and the North Bend (Bruce) drilling. The results from this study have since been followed up by surface exploration drilling, and have played an integral
NINTH INTERNATIONAL MINING GEOLOGY CONFERENCE / ADELAIDE, SA, 18–20 AUGUST 2014
STRUCTURAL CONTROLS AND STRAIN PARTITIONING IN THE RED OCTOBER GOLD MINE, WESTERN AUSTRALIA
A
A
B B
FIG 11 – An example of predictive targets based on combined geomechanical model results.
FIG 12 – Recent exploration reverse circulation drill hole resulting in mineralisation, the location of the drill hole is overlain on geomechanical model outputs (A) looking north-west and (B) looking north-east. Note the drill hole location through the main shear zone and its correlation with primary targets.
FIG 13 – A long section view of the resource block model in August 2013, and the high-grade zones (red circles) associated with the Smurf and Smurfette intersections with the main shear zone. Red blocks are representative of grades above 20 g/t Au. Note the conjugate pattern trends of higher grades. NINTH INTERNATIONAL MINING GEOLOGY CONFERENCE / ADELAIDE, SA, 18–20 AUGUST 2014
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part in the exploration strategies for the mine. One surface RC exploration hole has been drilled since the geomechanical modelling work was completed in October (Figure 12). The hole was 732 m deep, targeting a hypothesized high-grade shoot. This high-grade shoot was defined by core logging of a Smurf style structure at approximately the ~600 RL which returned a grade of 0.3 m at 18 g/t Au. Upper mining levels have shown that where Smurf style mineralisation has interacted with the Red October Shear zone, there is an increase in both grade and width (Figure 13). This theory was tested to the lower intercept of Smurf style mineralisation. The RC hole intersected shale mineralisation at a depth of 707 m, approximately 40 m to the north of the intended target. The grade was 4 m at 3.8 g/t Au, which included 1 m at 8 g/t Au. Follow up testing is currently being planned for mid-2014. The North Bend (Bruce) drilling is currently under review due to mixed results in both grade and lithology.
CONCLUSIONS The geomechanical modelling of the Red October Deposit has highlighted and validated the numerous high-grade zones that exist within proven areas (previously mined) and suggest several potential areas of high-grade mineralisation relative to the Red October Shear zone. These zones are dependent upon the interaction of the footwall subsidiary structures, quartz breccia (Marlin) and Smurf style mineralisation structures. At current, there is limited drilling data available from the current life-of-mine resource limit at the 1000 RL, down to the 660 RL where the shale was intercepted. Going forward, future exploration targets are now cross-referenced with geomechanical results, particularly zones of high volumetric strain increments (dilation), and high values of shear strain, highlighted from the GMEX work. These target zones are then checked with selective holes from the Red October drill hole database, with a specific interest of identifying the subsidiary structure mineralisation at depth. Having a better understanding of the geological processes through simulation of the deformation events, using geomechanical modelling technologies, has led to more informed decision-making and exploration success at the Red October Gold Mine. This has a two-fold benefit from an exploration and resource viewpoint: 1. The validation of the geomechanical modelling against proven resources provides confidence in using the results as a critical input into successful exploration targeting. It also provides a greater understanding of critical structural controls and system response during deformation events, which has great benefits in making exploration decisions. 2. Understanding the key role of structures provides clues to understanding grade control, particularly when dealing with narrow vein systems. From a resource and grade control point of view this information allows us to better plan and determine mining development and strategies.
ACKNOWLEDGEMENTS We would like to thank Saracen Minerals Pty Ltd and Saracen Gold Mines Pty Ltd for supporting this project and the
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release for publication. This work was conducted through a 1:1 consultancy project with Saracen Gold Mines and GMEX (Geological Modelling for Exploration).
REFERENCES Blewett, R S and Czarnota, K, 2007. The Y1-P763 project final report November 2005, module 3 – terrane structure: tectonostratigraphic architecture and uplift history of the Eastern Yilgarn Craton, Geoscience Australia record 2007. Blenkinsop, T G, Baker, T, McLellan, J G, Cleverley, J and Nugus, M, 2007. Sunrise Gold mine geological study project G15, final report, Predictive Mineral Discovery Cooperative Research Centre. Ge, S and Garven, G, 1992. Hydromechanical modeling of tectonicallydriven groundwater flow with application to the Arkoma Foreland Basin, Journal of Geophysical Research, 97:9119–914. Gow, P A, Upton, P, Zhao, C and Hill, K C, 2002. Copper-gold mineralisation in New Guinea: numerical modelling of collision, fluid flow and intrusion-related hydrothermal systems, Australian Journal of Earth Sciences, 49:753–771. Hobbs, B E, Muhlhaus, H B and Ord, A, 1990. Instability, softening and localization of deformation, in Deformation Mechanisms, Rheology and Tectonics, Geological Society Special Publication (eds: R J Knipe and E H Rutter), pp 143–165. Ord, A, 1991. Deformation of rock: A pressure-sensitive, dilatant material, Pure and Applied Geophysics, 137(4):337–366. Ord, A and Oliver, N H S, 1997. Mechanical controls on fluid flow during regional metamorphism: Some numerical models, Journal Metamorphic Geology, 15:345–359. McLellan, J G, Oliver, N H S and Schaubs, P M, 2004. Fluid flow in extensional environments: numerical modelling with an application to Hamersley iron ores, Journal of Structural Geology, 26(6–7):1157–1171. McLellan, J G, Blenkinsop, T G, Nugus, M and Erickson, M, 2007. Numerical simulation of deformation and controls on mineralisation at the Sunrise Dam Gold Mine, Western Australia, SGA Dublin 2007 Digging Deeper Extended Abstract Volume, 2:1455–1458. McLellan, J G, O’Sullivan, R, Miller, B and Taylor, D, 2014. Geomechanical modelling of the Mount Isa copper deposit – predicting mineralisation, in Proceedings Ninth International Mining Geology Conference 2014, pp 197–206 (The Australasian Institute of Mining and Metallurgy: Melbourne). Nugus, M, Oliver, N, Blenkinsop, T G, Hill, J, McLellan, J G, Cleverly, J, Fisher, L, Brunacci, N, Moore, H and Jenkins, A, 2014. Exploration and innovation – the discovery and evolution of the 2 Moz Vogue gold resource, Sunrise Dam Gold Mine, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014, pp 323–340 (The Australasian Institute of Mining and Metallurgy: Melbourne). Schaubs, P M, Rawling, T J, Dugdale, L J and Wilson, C J L, 2006. Factors controlling the location of gold mineralisation around basalt domes in the stawell corridor: insights from coupled 3D deformation – fluid-flow numerical models, Australian Journal of Earth Sciences, 53:841–863. Standing, J G, 2008. Terrane amalgamation in the Eastern Goldfields Superterrane, Yilgarn craton: evidence from tectonostratigraphic studies of the Laverton Greenstone Belt, Precambrian Research, 161:114–134. Vermeer, P A and de Borst, R, 1984. Non-associated plasticity for soils, concrete and rock, Heron, 29:1–62.
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