Innovative solution to modelling a tightly folded orebody
Crocodile Gold’s Cosmo project is in the Northern Territory of Australia, approximately 150kms south of Darwin and is currently mined as an underground operation. The Cosmo mineralisation lies within a folded overturned sedimentary anticline, with the mineralisation in the hinge having undergone tight isoclinal folding. These folded areas posed some challenges for block model estimation. The mine had already chosen to use Surpac software, which has no unfolding algorithms and did not wish to invest in other general mine planning software.
Initially, the Crocodile team had developed a panel estimation method to handle folded zones using Surpac macros. This method worked well for nearest neighbour and inverse distance methods, but the macros needed to be enhanced to use ordinary kriging.
Once the panel method had been improved to include ordinary kriging, some minor issues became apparent when modelling the tighter isoclinal folds.
Crocodile Gold approached Cube Consulting to get ordinary kriging implemented in their in-house panel estimation system. This was done and Cube ran the resource estimate for Crocodile for their statutory May 2013 NI43-101 report.
The next step was to handle the more complex geometry issues. The Geology Manager engaged with the Cube geology team to develop a new methodology (the sector method) using Surpac. This method was developed using TCL macros and the resultant model forms the basis of the most recent December 2013 NI43-101 report for Cosmo. Cube Consulting also assisted with some statistical analysis and report compilation.
There is plenty of Surpac experience within Cube Consulting, which helps when trying to create something new and innovative.
The internal peer review process within Cube and access to geologists with diverse expertise leads to a better outcome for the client.