Creating Grade Thickness Models

RockWorks | Utilities | Volumetrics | Grade -> Grade Thickness (GT)

Given a solid model that contains grade values (e.g. percent eU308) this program will produce a GT (grade-thickness) grid and contour map in which the contours represent the grade multiplied by the thickness. In other words, high valued areas may represent either thick zones of lower-grade ore or thin zones of high-grade ore.

Here's how the program works: For each column of voxels within the initial grade model, the "sum" of voxel GT values is computed and saved as the GT value within the grid model. These voxel GT values are computed by multiplying the grade value by the voxel height. If a voxel grade value is less than the user-specified cutoff (minimum acceptable grade value) the voxel will not be included in the summation. If the final sum is below the user-specified cutoff (minimum acceptable grade-thickness), the program will set the corresponding grid value to zero.

! This tool requires that a solid model containing grade values already exists (Solid | Model, I-Data | Model, etc.)

Menu Options
Step-by-Step Summary
 

Menu Options

• Input Columns:  If you request plotting of 2D map symbols (below) AND if you have data loaded into the Utilities datasheet, you can use these prompts (along the left edge of the Options window) to specify the X and Y locations for the map symbols.  If you don't plot map symbols, these will be ignored.
  • X (Easting): Click here to select the name of the column containing the X or Easting  coordinates.
  • Y (Northing): Click here to select the name of the column containing the Y or Northing coordinates.
     
• Input (Grade) Model: Click to the right to browse for the solid model (.RwMod file) that contains the Grade values to be processed.
   
• Output (Grade-Thickness) Grid:  Click to the right to type in the name to assign to the output grid model (.RwGrd file), which will represent Grade * Thickness.
   
• Minimum Acceptable Grade Value: Type in the minimum grade value of interest in the input model.
   
• Minimum Acceptable Grade-Thickness: Type in the minimum acceptable grade-thickness value.
   
• Create 2-Dimensional Grid Diagram: Insert a check in this check-box if you want to display the output grid as a 2D map at this time.  Expand this heading to set up the 2D map layers (bitmap, symbols, labels, line contours, color-filled contours, labeled cells, and/or map border).
   
• Create 3-Dimensional Grid Diagram: Insert a check in this check-box if you want to display the output grid as a 3D surface.  Expand this heading to set up the 3D map layers (flat surface, Boolean colors, perimeter, reference cage).  You can request both a 2D and 3D representation of the grid model.
  ! Since the grade * thickness values may be quite large, you may find it best to display your 3D surface as flat.
   
• Create Grid Statistics Report: Insert a check here if you want to see a report summarizing the output grid. 
  • Include Standard Deviation:  Check this box if you want the report to include standard deviation.
  • Include Directional Analysis:  Check this box to include slope, aspect, and strike computations. Be warned that these can take a few moments for large grid models.

Step-by-Step Summary

1. Access the RockWorks Utilities program tab. 
2. Select the Volumetrics | Grade -> Grade Thickness (GT) menu option. 
3. Enter the requested menu item, described above. 
4. Click the Process button at the bottom of the window to proceed.

The program will read the input solid model and determine those voxels whose Grade values fall below the minimum threshold, discarding them.  The remaining voxel grade values will be multiplied by the voxel height, to represent Grade * Thickness (GT).  The program will scan each vertical column of voxels, adding up the GT values. For each column, if the total exceeds the minimum GT threshold you've defined, that GT total will be assigned to the corresponding grid node in the output model.  If the total GT value for the column is less than the threshold, the corresponding grid node will be assigned a value of 0.

If requested, the report will be displayed in a text tab in the Options window. The requested diagram(s) will be displayed in a RockPlot2D tab and/or RockPlot3D tab in the Options window.  

5. You can adjust any of the settings in the Options window and then click the Process button again to regenerate the diagram(s).
   ! Each time you click the Process button, the existing display(s) will be replaced.
    
6. View / save / manipulate / export / print the diagram(s) in the RockPlot2D or RockPlot3D windows. 
   
   

Back to Volumetrics Menu Summary

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