One of the many tasks a Resource or Project Geologist carries out is to interpret mineralized zones using logged geological intervals and assayed grades. These interpreted zones are then wireframed and used to constrain the drillhole database for compositing and constraining the block model for resource estimation.

Wireframes are easily created in Surpac by digitizing the interpreted mineralized zone on section, making sure the digitized segments are snapped to the drillhole sample intercepts and, then, explicitly modeling the zones by creating a wireframe model using the interpreted segments.

Explicit modeling can be performed using any third-party geological mine planning software. More recently, wireframe modeling has been performed using implicit radial basis function (RBF) modeling methods or a combination of both implicit and explicit modeling.   

Each third-party geological mine planning software may use a variety of curved trace algorithms for the display of the drillhole traces. When using a Surpac composting workflow, it is important to check that wireframes are snapped correctly to drillhole intercepts before coding the database so that grades are not smeared into incorrect mineralized zones. 

This used to be a painstaking manual process, but now, there is a new automatic function to carry out the checks and adjustments. 

In this blog we will look at the steps to automatically correct wireframe drillhole intercepts.

• Open up the drillhole database and display the drillholes. REMEMBER to tick the box to optimize performance for text if the database is large and text is being displayed.
   

• Create a set of planes using quick planes 
• Display the drillholes, the wireframe vertices and the points. 
• If you wish to change the graphics background color, then you can use the new function “Invert graphics canvas color” 

• When you move through the sections, you may notice that the wireframe is not snapped correctly to the drillhole, but in the third-party software, they were. Remember each third-party software may use a variety of curved trace algorithms, which affects the positioning of the drillholes. 

• Database>Analysis>Highlight common points. This will highlight points that are not snapped correctly to the sample intercept. 

• The Domain table is the table you want to compare the wireframe to. This would usually be the table that contains the sample/assay values. 

• Tolerance Value is the distance from the snapped string point/wireframe vertex to the assay interval. It is important use a tolerance that will capture the points that are not snapped to the correct sample intercept, otherwise the intercepts will not be highlighted. In this example we used a tolerance of 0.25. If you use Bearing and Distance (BD) to measure the distance between a few points and the assay intervals, read the slope distance you will get an idea of the tolerance distance to use.

• Once the function has run, move through the sections to view the wireframe/string points that do not match up with the assay/sample intervals. If the tolerance distance is too small, then they will not be highlighted. Use “Bearing and Distance” to measure the distance between the drillhole and the string point/wireframe vertex. If you have diamond drilling with small intercepts, you may want to run the function in stages. 

• If you notice that valid intercepts are not being picked up, it may indicate that the tolerance distance is too small, and you may need to adjust it accordingly to ensure all relevant points are captured.

• Once the highlighted points have been validated, you can then use the “Adjust Common Points” Function. This process adjusts the wireframe so the points are snapped correctly for compositing. 

NOTE: if the wireframe and database are big, this may need to be carried out in a stage approach. 

• This wireframe can then be used to code the zone/domain table for compositing and the block model.

For validation tricks and tips using third-party wireframes created by Implicit and/or Explicit modeling methods refer to the article “Validation of Third-Party Solids”