Inserting Missing Intervals

Although a well-designed drillhole database should never have gaps between adjoining intervals, many
databases do. Missing intervals can cause validation problems during drillhole compositing, which has later implications during implicit modelling and resource estimation.

To resolve this problem, use Drillhole | Data | Insert Missing Intervals with Use Collar File enabled (Figure 1). This configuration inserts intervals into gaps along the entire hole, provided you supply both an interval and collar file. In situations where a collar file is not used, for example, with a desurveyed interval file, disable Use Collar File. This configuration inserts missing intervals between the first and last logged intervals and could miss gaps at the collar and end of hole.

Figure 1: Example Insert Missing Intervals form.

After running this tool, your file will contain all of your original data, plus additional empty intervals; empty intervals have a Hole ID and From/To depths but no attributes of interest. Now, when drillhole compositing, you can choose to handle these intervals as either waste or null values. When implicit modelling, the algorithm is better informed on where to restrict the model. Finally, when performing resource estimates, you have more flexibility on whether to handle these empty intervals as waste or null values. 

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