Being
tasked with updating an old model using only static meshes and historic data
can seem like an overwhelming task.
This
workflow shows how to take static meshes, add them into a Geological Model,
back-flag them against drillhole data, and then create a dynamic Leapfrog Geo
model and avoid intense manual work.
In this example we’ll look at a barren dyke system that is cross cutting our mineralized body. We’ve been given two barren meshes to use as a starting point and need to update the shapes with additional drill and mapping information. Ensure that the meshes are valid for this process to work.
First, we’ll create a new Geological Model with <None> as the Base Lithology Column. The model extents can be chosen to Enclose the meshes (or as required).
Double click on the lithologies tab in the GM and Add new Lithologies to match the names of the meshes. In this case we’ve added in Dacite Dyke 1 and Dacite Dyke 2.
We are now ready to add these meshes into the Geological Model. Right click on the Surface Chronology → New Intrusion → From Surface.
Select the mesh, use the drop down to set the First lithology to the corresponding mesh lithology and the Second Lithology as Unknown. Repeat for as many meshes as required.
Once all of the meshes have been added in, double-click on the Surface Chronology and tick all surfaces to activate (set relative ages – youngest at the top).
Output volumes have now been generated for these meshes and we’ll evaluate them against the drillholes. Right-click on the Drillholes object → New Evaluation, then select the relevant model.
This will create a new table in the Drillhole Data folder –
by expanding this table we can see a hyperlink back to the evaluated model.
The intercepts between the original meshes and the drillholes are now flagged in the database. An evaluated table can be exported to csv or queried.
In order to create a dynamic model from these intervals we’ll create a New Merged Table and an interval selection on this table. Right-click on Drillholes → New Merged Table. Select the Evaluation, the lithology data, and the assay data (or any other data we’d like to be able to model with).
This creates another new table in the Drillhole Data folder. We can now create an Interval Selection on this table in order to utilise the flagged intervals. Right-click on the Merged Table → Interval Selection → select a base lithology column (either lith or perhaps a category from numeric).
This displays an Interval Selection window. Edit mode can be activated by selecting the pencil on the merged table in the Shape List. Change the drop down in the Shape List to the evaluated model.
The drillholes should now be coloured by the back-flag /
Evaluation lithologies.
- Click on the ‘Edit Colours’ button in the Shape
List and hide everything except for one code – in this example Dacite Dyke 1 - Click the Select all visible intervals button in
the tool bar (Ctrl + A). - Use the Assign to dropdown in the Interval
Selection editing window and assign to ‘Create New Lithology’ - Add in the lithology e.g. Dacite Dyke 1 and
click OK
Repeat for remaining lithologies – below Dacite Dyke 2 is selected and assigned to a new category.
Save the interval selection and close the interval selection
display window. Change the dropdown for the merged table in the Shape List back
to Lith_Selection, click on Edit Colours and hide everything except for the
flagged new lithologies.
We’ve now taken our static meshes, added them into a geological model to obtain volumes, flagged them against the drillholes, added them into a merged table, interval selected them into a lithology column. We can now create a new geological model and use this interval selection to re-create the shapes dynamically.
Next, we will create another new Geological Model, set the interval selection from the merged table as the Base lithology column. Set the surface resolution to something appropriate and change the extents as required.
Right-click on the Surface Chronology → New Vein (or other surface type if appropriate) → From Base Lithology. Select the Vein lithology – Dacite Dyke 1 – click OK. Repeat for all other surfaces.
The surfaces are now fully dynamic Leapfrog Geo shapes. They
can be updated with additional drill information, mapping data, manual
interpretation.
Drag the old meshes into the Scene View to compare with the dynamic surfaces. There may be minor differences from the original mesh shapes; these could be due to snapping setting, explicit vs implicit modelling, surface resolution, other inputs or manual interpretation. In the majority of cases, the difference is often negligible however it is recommended to review the new shapes and further refine as needed to ensure outputs are acceptable.
The backflag GM and Evaluation table can now be deleted from
the project without affecting the final dynamic model.
This workflow demonstrates how to take static meshes and convert them into a dynamic Leapfrog Geo model. It allows geologists to continue to build upon existing work ensuring new data is incorporated and can be easily updated going forward.
As always, you can reach out to you local Technical Support team with any questions,