Processing Drillhole Data
Once imported and corrected, drillhole data usually requires further processing before any models are built.
Often, selecting a small portion of intervals can be achieved using a query filter (see the Query Filters topic). In some cases, however, you may wish to composite data to focus on a single unit. There may also be issues with how drillhole data has been recorded; for example, two units have been catalogued as one, or a single unit may be divided into multiple units.
Leapfrog Geo has a number of tools for processing drillhole data, including:
- Category Composites. Sometimes unit boundaries are poorly defined, with fragments of other lithologies within the lithology of interest. This can result in very small segments near the edges of the lithology of interest. Modelling the fine detail is not always necessary, and so compositing can be used to smooth these boundaries.
- Economic Composites. Economic compositing classifies assay data into “ore” and “waste” categories, taking into account grade thresholds, mining dimensions and allowable internal dilution. The result is an interval table with a column of ore/waste category data and a column of composited interval values, plus some additional columns showing the length, linear grade, included dilution length and included dilution grade.
- Majority Composites. Category data can be composited into interval lengths from another table or into fixed interval lengths. The compositing is based on a majority percentage where each interval is assigned a category based on the category that makes up the highest percentage of the new interval.
- Numeric Composites. Compositing numeric data takes unevenly-spaced drillhole data and turns it into regularly-spaced data, which is then interpolated. Numeric data can be composited along the entire drillhole or in selected regions. You can also set the compositing length from the base interval table.
- Grouping Lithologies. The group lithologies tool lets you define a new unit to which existing units are added. For example, a sandstone deposit might appear in an interval table as poorly-sorted and well-sorted units. The group lithologies tool lets you group both units into a single sandstone unit.
- Splitting Lithologies. Lithology units may be incorrectly grouped, which can become apparent when you display drillholes in the scene. The split lithologies tool lets you create new units by selecting from intervals displayed in the scene.
- Interval Selection. If the lithologies in a column are poorly sorted, you can display the column in the scene and use the interval selection tool to work with all the segments and sort them into new units.
- Overlaid Lithology Column. You may have two versions of an interval column, one that contains draft data and one that contains the final version. The final version may contain gaps, which can be filled in using the draft version. The overlaid lithology tool lets you combine the two columns to create a new column.
- Category Column from Numeric Data. When you have numeric data you wish to use with the lithology and category modelling tools, you can convert the numeric data to a category column.
- Back-Flagging Drillhole Data. Evaluating geological models on drillholes creates a new lithology table containing the lithologies from the selected model.
Each of these tools creates a new interval table or creates a new column in an existing interval table, preserving the original data. New tables and columns can be used as the basis for new models in the project and can be incorporated into existing models using From Other Contacts options. When a new table is created, you can view it in the scene along with the original table to see the differences between the processed and the unprocessed data.
If you are working with columns in different interval tables, you can create a new merged table that includes columns from these different tables. Columns created in Leapfrog Geo can be included in a merged table. See Merged Drillhole Data Tables.
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