The latest version of Supervisor (Version 8.8) is now available and includes two new features, a contact analysis tool and rotation of model validation trend plots.
The new release includes a contact analysis tool which allows contact graphs to be easily generated for all domain boundaries.
It is important to know the nature of the contact between domains when estimating a resource so that appropriate boundary conditions can be used. There are three broad classifications of domain boundaries – hard, gradational or fuzzy.
- Hard boundary – abrupt change in grade over a short distance across the domain boundary. For a hard boundary, only samples within the domain should be used for estimation.
- Gradational or soft boundary – gradual increase/decrease in grade across the boundary. Depending on the search criteria being used (namely the search distance and number of samples allowed per drillhole), this boundary may be ignored for the purposes of grade estimation.
- Fuzzy or mixed boundary – a transitional zone across the domain boundary but over a relatively limited distance. A fuzzy boundary is typically used where only samples a certain distance beyond the contact can be used for estimation.
A contact analysis involves graphing the drillhole sample grades as a function of the distance away from the contact. An example of a hard domain boundary is illustrated in the contact analysis below using Supervisor’s new contact analysis tool. The contact analysis charts also include a linear regression line (red line) based on the data at the selected maximum distance from the contact, along with lines (grey) at the 95th and 5th percentiles.
Rotation of validation trend plots
Past versions of Supervisor’s easy to use, intuitive model validation tool generated grade trend plots in the east-west, north-south and horizontal planes. The trend plots compare the average drillhole grades with the average block model estimates within each slice in the three directions.
The new release includes two additional trend plots which can be rotated to better reflect the strike and across-strike directions of each domain. This provides a better indication of how well the block model estimates compare with the drillholes in these directions. The rotation angle can either be picked up from the variogram directions or set manually.
This functionality is illustrated in the diagram below for a sub-horizontal mineralised domain which strikes approximately northwest-southeast. The orientation of the trend plot slices (red lines) have been rotated to align with the strike direction of the mineralisation. In this example, east-west or north-south oriented trend plots would be sub-optimal.
Additionally, the tonnes (or volume) for each slice from the block model can now be shown on the trend plots.