Ailleres, Laurent1, Grose, Lachlan1, Caumon, Guillaume2, Jessell, Mark3
1School of Earth, Atmosphere and Environment, Monash University, Melbourne, Australia, 2RING, Université de Lorraine, Nancy, France, 3CET, University of Western Australia, Australia
Loop is a OneGeology initiative, initiated by Geoscience Australia and funded by Australian Territory, State and Federal Geological Surveys, the ARC and the MinEx CRC with the participation of BHP, Anglo American, GSWA and Micromine. The project is led by Monash University and involves research groups from the University of Western Australia, the RING consortium at the Universite de Lorraine, Nancy, France and RWTH Aachen in Germany. In-kind research is also provided by Natural Resources Canada (Geological Survey of Canada), Geoscience Australia, the British Geological Survey and the BRGM.
We have implemented the use of all structural geological data (e.g.: fault kinematics, fold axial surfaces, fold axes, deformational overprinting relationship) in the modelling process. We have automated the building of 3D geological models from geological survey served geological data including automatic geological map topological analysis and geological history building. As a proof of concept, users can now draw a polygon on a map and generate 3D models in just a few minutes using the map2loop and LoopStructural libraries. (github.com/Loop3D/LoopStructural & github.com/Loop3D/map2loop-2)
We are integrating geophysical constraints and modelling as early as possible in the modelling workflow. Model uncertainty is characterised and an integral part of the modelling process. We are in the process of generalising the use of Bayesian modelling to 3D structural geological modelling.
The main outcome of the development of the structural modelling method (LoopStructural) is the definition of structural frames. A structural frame is interpolated throughout the entire modelled volume and is associated to each structural event or object and their corresponding finite strain axes. Each fault has a structural frame (Fig.1) based on the geometry of the fault (faults are not necessarily planar) and the damage zone defined by an ellipsoid representing the decay of the offset in all directions (slowest decay along the throw direction). A fold event has a structural frame defined by a direction normal to the axial surface foliation, a direction parallel to the fold axis and the last axis is parallel to the extension direction. Combining these different events, in a time-aware manner, is the essence of LoopStructural.
LoopResources will be the property estimation library for the Loop platform. During modelling, the time-aware application of structural frames results in the implicit definition of a curvilinear rectangular coordinate system everywhere in the model and conformable to geological layering. Using this deformed cartesian coordinate system, we propose to adapt geostatistical and interpolation methods (e.g. kriging) to curvilinear coordinate systems. This will ensure that lithological anisotropies are enforced during resource estimation and property modelling.
The proposed outcomes improve significantly on current capabilities and will provide a machine-supported decision system for 1) improved domaining, 2) optimal definition of ore blocks of consistent ore grades, geotechnical properties, and crushing requirements, 3) optimal extraction, crushing and processing costs, and 4) increased recovery rates.
In essence, building a much better digital-twin representing the geology, distribution of resources, the geometallurgical and geotechnical characteristics of a mine will ensure better mining of deposits and ultimately better mine footprint.
Laurent is a structural geologist interested in the evolution of tectonic processes through time and their effect on multi-scale mineralisation processes. He specialises in structural geology and geophysics as well as multi-scale 3D geological modelling applied to minerals systems. He leads the Loop initiative champions structurally-ruled probabilistic 3D geological modelling.