New systems for geological modelling - black box or best practice?
C Birch
A ‘geologically constrained’ orebody model has long been hailed as vital for
a Mineral Resource statement that is compliant with the South African
Code for Reporting of Exploration Results, Mineral Resources and Mineral
Reserves (SAMREC Code). In this paper, the requirements for geological
modelling as contained in the outline for the SAMREC Code are considered,
and whether the new modelling software available on the market is a
‘black box’ or is better for modelling than traditional methods of wireframe
creation.
Implicit geological modelling is a technique that uses a radial basis
function to establish and update geological models relatively quickly and
efficiently from borehole data, outcrop data, manually interpreted vertical
or horizontal sections, and structural data. Assays and any coded drill-hole
data, such as lithology and alteration, can be interpolated.
Leapfrog Geo software is an example of this new approach to
geological modelling. A case study of a short training course in geological
modelling for non-geologists at the University of Witwatersrand, as part of
the Higher Certificate in Mineral Resource Management, is presented. The
benefits of this type of geological modelling software are considered for
this type of assignment as well as for mining industry applications.
The use of geological models in mine planning is reviewed and a case
study is presented comparing the variations in mine plan design and
financial output of 13 final-year Mine Design projects from the University
of the Witwatersrand School of Mining Engineering. These designs were all
based on the same geological model created in the traditional way, and yet
the resultant mine designs were significantly different, with very different
resulting financial outlooks for the project. This raises questions as to how
significant a very detailed model in the pre-feasibility and feasibility
phases of projects really is, considering the huge costs involved in
gathering the required data to build a SAMREC-compliant geological model.
Keywords
implicit geological modelling, mine design, software.