A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Mining Engineering.
February, 2016 / Mineral Resource estimation provides an assessment of the quantity, quality, shape and
grade distribution of a mineralised deposit. The resource estimation process involves; the
assessment of data available, creation of geological and/or grade models for the deposit,
statistical and geostatistical analyses of the data, as well as determination of the appropriate
grade interpolation methods. In the grade estimation process, grades are
interpolated/extrapolated into a two or three – dimensional resource block model of a
deposit. The process uses a search volume ellipsoid, centred on each block, to select samples
used for estimation. Traditionally, a global orientated search ellipsoid is used during the
estimation process. An improvement in the estimation process can be achieved if the
direction and continuity of mineralisation is acknowledged by aligning the search ellipsoid
accordingly. The misalignment of the search ellipsoid by just a few degrees can impact the
estimation results. Representing grade continuity in undulating and folded structures can be
a challenge to correct grade estimation. One solution to this problem is to apply the method
of Dynamic Anisotropy in the estimation process. This method allows for the anisotropy
rotation angles defining the search ellipsoid and variogram model, to directly follow the
trend of the mineralisation for each cell within a block model. This research report will
describe the application of Dynamic Anisotropy to a slightly undulating area which lies on a
gently folded limb of a syncline at Driefontein gold mine and where Ordinary Kriging is
used as the method of estimation. In addition, the optimal Dynamic Anisotropy resolution
that will provide an improvement in grade estimates will be determined. This will be
achieved by executing the estimation process on various block model grid sizes. The
geostatistical literature research carried out for this research report highlights the importance
of Dynamic Anisotropy in resource estimation. Through the application and analysis on a
real-life dataset, this research report will put theories and opinions about Dynamic
Anisotropy to the test.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/20591 |
| Date | January 2016 |
| Creators | Mandava, Senzeni Maggie |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (137, [3] leaves), application/pdf, application/pdf |
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