Eureka uses the Radial Basis Function (RBF) methodology as a tool for understanding structurally complex deposits. RBF is a form of implicit modelling.
Design strings, points, ribbons, drillholes, triangulations and scans - and any combination of these - can be used as input for the modelling process.
A surface is created from the input data; the constituent points form on the surface. For drilling data, Eureka creates a surface from drillhole points matching assay values or formation codes.
The above image shows a surface representing high grade layers within a banded iron formation.
The Maptek Vulcan ISIS database was accessed by Eureka. The surface was generated from iron assay values exceeding 60% Fe.
A slice shows the iron assays contained within the surface in the image below. Values on the drillholes of 60% or greater are displayed as orange; less than 60% are grey.
Interpretation ribbons can now be used for better control of the resultant model.
Ribbons can be used like strings or points to add data points, but they differ from strings in that they have 2 sides. This is represented by double-sided colouring below.
Ribbons may also be used individually to create surfaces from complex and overturned strings. The surface obeys the direction of the ribbon, with the inside of the surface matching one side of the ribbon and the outside matching the other.
Ellipsoids influence the model by deforming the space in which the sample points sit. The model then becomes stretched or contracted in the directions of the ellipsoid.
The size of the ellipsoid has no influence; the ratios between the directions of the ellipsoid, as indicated by the coloured bands, control the orientation, as well as the ratio between different axes in the ellipsoid below.
Ellipsoids are particularly useful for modelling steeply dipping deposits, as they direct the surface generation along the trend of the deposit. Multiple ellipsoids can be used in combination to honour local structural trends.
Borehole graphics, seismic and implicit modelling modules can be added to a base Eureka licence.
For further information, email eureka.sales@maptek.com.au