Computational Modelling in Mining and Exploration
Mineral deposits can be found by understanding the areas in the earth’s crust that will facilitate fluids responsible for mineralising events. The geomechanical response of the crust to deformation events can result in shear zones, faults and breccias, which are all important fluid conduits. Identifying areas of stress anomalies and rock failure is difficult using empirical methods, and many deposits are now found undercover. Computational modelling provides a method to test the ‘geological process’ and results in a more comprehensive understanding of the system. The predictive nature of this form of modelling and analysis allows prediction of structural scenarios, which can a) identify areas with a higher probability of deformation localisation, b) identify areas of fluid focussing, and c) identify areas with low favourability. All of these factors will enhance the full understanding of any exploration target area and serve to increase the probability of significant deposit discovery.
Rockfield has combined their expert geological and exploration knowledge with computational analysis to conduct predictive mineral exploration based on structural histories and subsequent deformation sequences. Rockfield’s experience in this field incorporates fully coupled geomechanical, thermal and fluid flow Finite Element Analysis (FEA). The techniques involve definition of 3D stress/strain and fluid localisation as applied to mineral deposits and mineral exploration at local to regional scales. This 3D FEA can be carried out at all scales and incorporate porous media flow and thermal inputs such as intrusive heat sources. Rockfield has carried out projects at regional scale to define the structural evolution and highlight important areas of deformation loci and fluid focussing, which greatly assists in tenement selection. At the local or mine scale, Rockfield can adapt mine models or current 3D conceptual models based on the geology and drill data, and then apply deformation scenarios to highlight stress/strain partitioning and areas of fluid focussing. This has great benefits in resource mining procedures (i.e. to ensure no mineral resource is left behind) and within mine (or near mine) exploration projects.
Rockfield also provides complex 2D discrete element analysis. Using structural reconstructions we can model paleostress and highlight areas most likely to focus mineralising fluids in structurally controlled deposits, incorporating commodities such as Au, Ag, Pb, Zn, Cu, Cu-Au, U, Mo and Fe Ore. Using these techniques allows mining and exploration companies to rapidly test varied structural scenarios to better understand the structural history and mineralising processes. Rockfield’s techniques provide vital information for informed decision making before target drilling commences. These techniques can be used in both Brownfield and Greenfield terranes.
Coupled Geomechanical and Fluid Flow Modelling
Rockfield’s specialist skills using finite element analysis (FEA) can create realistic geometry as inputs to computational models, and then apply deformation to these models to simulate structural events through time. Utilising continuum modelling and fully coupled interactions Rockfield can show the complexity and response of the deformation in terms of stress/strain, failure modes and associated fluid flow. The interpreted results highlight how deformation is partitioned through time, and the resultant effects of fluid migration in the earth’s crust. For example, Rockfield can indicate areas of rock dilation and the focussing of fluid flow as a response to increasing levels of deformation.
Rockfield’s modelling techniques and outputs provide a greatly improved understanding of the geomechanical response of the crust and how it has affected fluid migration. Having increased knowledge of the system will improve decision making when it comes to targeting mineral systems. Rockfield’s continuum modelling can be applied to hard rock and sedimentary environments to investigate various systems such as volcanogenic environments, rifts or basinal sediments. Our modelling can also be used to investigate the role of basement structures in covering sedimentary basins, which provides great insight into fluid migration in these settings.
Pore fluid pressure is an important aspect of fluid migration and this is fully coupled and integrated into Rockfield’s modelling process. The models can be varied to examine the effect of gradients, diagenetic processes, seals and aquifers, which also have a great influence over mineral systems. Rockfield can apply these models to both local camp/mine scale and regional terranes involving many systems such as Pb-Zn-Ag, Cu-Au, Archaean Granite-Greenstone Au, Uranium and Epithermal systems.
Discrete Element Spatial Stress/Strain Modelling
Rockfield’s Geoscience team has the ability and experience in modelling the partitioning of stress and strain during tectonic deformation events, which may predict areas more likely to undergo rock failure and fluid flow focussing, leading to an increased capacity for mineralisation. If structural controls have been important in focussing mineralising fluids then Rockfield’s techniques can produce suitable results to be coupled with your magnetic, radiometric (or other remotely sensed) data to give you the optimum data coverage for your exploration tenement.
These modelling techniques can be utilised at all scales (from regional tenement to local or mine deposit scales). Modelling outputs can be delivered in a format suitable for importation into your Geographical Information System (GIS) platforms. This allows data merging, for use in a prospectivity analysis. The data is also extremely useful to aid any exploration strategy and can assist when planning a drilling program for mineral exploration. Rockfield’s modelling results can be particularly valuable for inaccessible areas or deposits undercover, and may highlight favourable stress/strain anomalies as a result of fault architecture or competency contrasts.
These techniques can also provide mining and exploration companies data that may suggest areas as being unfavourable in terms of structural complexity or localisation. This can reduce exploration costs by reducing favourable area size and increasing chances of deposit discovery.
Discrete Element Fault/Fracture Modelling
Rockfield has the ability and experience in modelling brittle rock deformation which can predict fracture propagation due to the influence of tectonic forces and fluid pressures. The prediction of fracture propagation can be extremely useful in both mineral and geothermal systems. We have the ability to combine continuum and discrete processes and use this to investigate both ductile and brittle deformation within the same model analysis.
Geothermal Coupled Modelling
Rockfield’s geosciences team has experience in modelling fully coupled deformation, thermal and fluid flow systems, where fluid convection in porous media may be important in mineral precipitation or dissolution. We also investigate advective fluid migration, which is an important aspect of geothermal energy considerations. We have experience in working in some of the best geothermal systems in the world (e.g. New Zealand), where the heat flow is more than 10 times the average crustal values causing vigorous convection systems.