Step 3: Define Geological Domains

Grouping your geological data into suitable domains for modelling is a key step in the modelling process. The domains you define may be influenced by the intended use of the geological model and may be more complex or simplified than what has been logged. It is important to have a non-destructive and repeatable workflow for defining the domains required for the modelling task, using tools that instill confidence or alert you to issues in the domaining decisions being made.

Vulcan GeologyCore’s Domain Manager is a tool that you can use to organise geological data into suitable domains. It is a central part of a repeatable process for defining the domains.

There are two ways in which domains can be defined:

Domain Rules

Use the Domain Manager tool to define rules to split or combine logged data, apply grade cutoffs, apply domain rules, and display charts to see changes in the domain statistics.

You can repeat the process of defining rules and inspecting charts until you are satisfied with the results.

The domaining tools are located in the Domain Definition group on the Modelling, DomainMCF and Stratigraphic ribbon tabs.

The Domain Manager is divided mainly into five sections to define names and rules for generating drillhole and sample domains.

The Domain Manager allows you to easily control how geological data is grouped into suitable domains for modelling.

To get started with domaining, follow these steps:

  1. Click Domain Manager on the ribbon. The Domain Manager panel is displayed.

    Note:  The domain codes and drillholes are automatically populated if there are existing domain groups.

  2. Select a Domain group name from the drop-down list if there are existing domains. However, you can create a new domain group, make a copy of or rename the existing domain groups, or import/export domain group rules.

    Create a new domain group
    Make a copy of the selected domain group
    Rename the selected domain group
    Delete the selected domain group
    Import the domain group rules

    Export the domain group rules

Input data

Select the input data for domaining first. In the Drillholes list, specify the set of drillhole inputs you want to run domaining on.

You can specify multiple databases and set up rules on them individually. For example, if different logging codes have been used for the same units in historic databases, or if numeric cutoffs define domains in production holes, while resource drilling has explicit logging.

Preprocessing

Configure and apply preprocessing filters before defining the domain rules. These data filters define what intervals the domaining is run on. These can be based on a field in the database or a region such as a blast solid in open pit models.

Domains

Configure the domain list.

The Domains section of the Domain Manager displays a list of domains to include in domaining runs.

  • To manually add a new domain code to the list, click . To delete a domain from the list, select it and click .

  • Optionally, populate domain codes from drillholes.


    Perform this step if you want to use domain codes defined in your database. Domain codes can be manually added later if you skip this step.

  • Deselect a domain’s checkbox in the Run column to exclude it from the domaining process without deleting it from the list.

  • The ordering of domains in the list is important if any rules could apply to more than one domain. The Order column indicates the order in which the rules of each domain are applied. Increase or decrease the precedence of an individual domain’s rules by selecting it in the list and clicking the or buttons.

  • Configure individual domain rules.

    When you select a domain in domain list, the rules associated with that domain are displayed in the Rules for <domain> section on the right-hand pane of the Domain Manager.

  • Click Edit to edit the domain’s rules.

    There are two kinds of rules that you can apply to intervals: filters and modifiers. Filters are rules that are applied to an interval to determine whether it should be included as part of a domain or not. Modifiers are rules that are applied to change interval boundaries according to some criterion. A domain’s filters are applied before modifiers are applied. If the Match entire drillhole filter option is selected, all intervals for a drillhole are passed on to the modifier.

    • Configure the domain’s filters on the Filter tab.

    • Configure the domain’s modifiers on the Modifiers tab.

  • Click Save to save the rule set as a template under a specified name.

  • Click Import to import a rule set from a previously saved template.

Postprocessing

Configure and apply postprocessing modifiers after defining the domaining rules.

Modifiers change interval boundaries according to some criterion when domaining is run. For example, you can set up modifiers to split or combine intervals. Global modifiers created on this panel are applied to every domain—but you can configure modifiers for individual domains in a later step.

Charts

Run domaining and display domain charts.

Whenever you run domaining with different rules, the statistics on your domains will change. Use domain charts to see the effect of the rules you’ve applied. You can tell the Domain Manager to automatically show charts on the domains you’ve selected each time you run domaining.

Follow these steps to run domaining with charts:

  1. Select the charts you want to generate.

    • Optionally click Open Charts to generate the charts immediately. The charts will display the current statistics—i.e. before domaining is applied.

    • Multiple grade charts can be generated simultaneously by clicking on the Add Grade Chart button and adding grade variables to the charts.

      Note:  Selecting domain grade charts but not selecting grade variables will still generate grade charts and you can select the grade variables once the charts are loaded.

  2. Choose a visualisation option from the Visualisation drop-down.

  3. Click Run domaining to apply the domain rules to the drillholes.

    When you do this, three things happen:

    • The domain codes are updated in the Intervals Table of the drillhole database(s). This table is created by Vulcan GeologyCore and means that the source tables for the intervals will not be modified by the domaining process.

    • Any charts you selected in the Charts tab are generated and displayed (or updated if they are already showing).


    • The drillhole visualisation updates based on the option you selected.

  4. Inspect charts (if generated).

    • The charts only include data from domains included in the domain list (i.e. have their Run checkbox selected). Because these charts are related to the current domaining run, they will close when you close the Domain Manager.

    • If you chose to generate a Domain counts chart, you can modify the set of domains to run from the chart. To do this, use the chart options to display the domains you are interested in (e.g. the domains with the highest counts), then click Update Domain Manager.

      The Run column of the domain list updates such that only domains in the chart are selected. This is useful when you want to quickly model the main units of a deposit.

Keep the Domain Manager open and re-run the steps above to refine your domain list and rule set until you are satisfied with the result.

Manual Flagging

For narrow vein workflows, where domain intervals are defined less by rules and more by manual interpretation, this can be achieved using the Flag Domains tool.

On the ribbon, navigate to Modelling > Domain Definition > Flag Domains.

The Flag Domains tool should automatically engage edge selection, but the selection method can still be changed manually as and when required.

Let us take the data shown in the image below as an example.

In the example, only the Undomained rule has been run to set a baseline for domain flagging. This is a useful way to approach a new deposit, or an area in which a new interpretation may be desired. However, if it is desirable to use existing domain codes as a starting point, these can be flagged automatically using the rule based approach prior to manual interpretation.

Apply visualisation settings

The first step in the manual flagging process is to ensure that the drillholes have appropriate visualisation settings applied to enable efficient flagging.

In this example, the drillhole trace has been displayed using the FROM geology grades and the FROM and TO geology grades have been displayed as labels on the right-hand side of the drill trace.

On the left-hand side of the drill trace, the lithology codes (LITH) have been displayed as a Label and the manual flagging field (Domain) has been displayed as a Flag and label, as this makes it easier to see the domain flagging as applied.

Click Apply to selection.

Flag domains

Once the visualisation settings is applied, it is time to flag the domains. Follow these steps to manually flag the domains:

  1. Select the intervals on the drill trace to be flagged as a new domain.

  2. Select the desired domain to apply from the row in the domains list grid.

  3. Select the Flag intervals button at the bottom of the panel to flag the selected intervals with the domain.

Example 1: Manual flagging with domain TQ2

Continue with other domains in the drillhole as desired. Here are some examples:

Example 2: Manual flagging with domain TQ1

Example 3: Manual flagging with domain TQ2

Tip:  Pressing CTRL + Space will deselect any current selections made in the view/explorer, which can help in enabling the selection of the next intervals quickly.

Step 2: Validate Drillhole Data

Step 4: Generate a Model