Search Ellipsoid Based on Grade Range in Surpac

By

The release of GEOVIA Surpac™ 6.7 earlier this year features design improvements for grade estimation by enhancing search ellipses and weighting length of composites. Significant increases in the processing speed of the block model enable geologists and engineers to see faster results of larger models with greater coverage or finer resolution. With multi-threading, Surpac 6.7 uses all of the available CPU cores to significantly increase the speed of high resolution modeling, analyzing much larger models in a fraction of the time. Its optimized performance allows the use of much larger models with very high sampling density, which has historically been difficult to collect and analyze in a single model.

Here is a tip to search ellipsoid based on grade range when working in Surpac 6.7

In a composite file, there may be high grade values disseminated in the domain. This method provides a way of handling the high grade values in the estimation.

The use of a single search distance is tending to bias the estimation and the high grade value will impact on any grade calculated at the maximum search distance set up. The result of this is the smearing of the high grade along the deposit. To avoid this kind of issues, it is recommended to restrict the influence area of the high grade.

The block model inverse distance and ordinary kriging estimation methods allows Surpac users to define a number of anisotropic search distances for specified grade ranges. Surpac users can restrict the samples selected in a manner that is sensitive to the magnitude of the sample grade.

This can help better estimate deposits with multiple populations of mineralization existing within a single estimation domain. Samples found within the maximum (default) search radius are considered for estimation, but the samples are included or excluded according to the anisotropic distances calculated using the values you have selected for each grade range.

This method is particularly useful for coarse grain deposits.

Looking for more Surpac Tips & Tricks? Check out these past posts on How to model a fault in Surpac and How to use the Weighted Composite in Surpac 6.7

0
Claver Gnamien

Claver Gnamien

Mining Knowledge Consultant, MAusIMM at Dassault Systèmes
Based in Perth, Australia, Claver has over 10 years of mining geology experience, specializing in the areas of grade control and reconciliation, resource estimation, block modelling, planning, supervision, logging, hydrogeology, and geotechnical engineering. He is also knowledgeable in the exploration of basic and precious metals, having previously worked as a Senior Mine Geologist and Geotechnical Engineer in Côte d'Ivoire, West Africa.