Optimized Pit Design

This command uses a max flow algorithm to determine the ultimate mineable economic pit. This is an automated routine with very few prompts. When the command is started, the first prompt is for a value block model (*.BM file). This file is created from the Prepare Value Block Model command which must be run before the Optimized Pit Design to create this file. After selecting the value block model file, the first dialog will then appear to set the slope angles on the various sides of the ultimate pit.

Azimuth and Desired Angle: The Azimuths are defined with 0 to the North, 90 to the East and 180 to the South The desired slope angles set in the dialog are measured in degrees from the horizontal direction.

After setting these angles, and selecting OK, the program will create a .TIN file of the optimum pit. The surface uses the blocks in full to create the slopes, which can look like benches if the blocks are made at the proper size in the original block model. This TIN file can then be viewed in 3D, contoured, or used to create linework for other pit design routines, such as Design Bench Pit.

The command line displays text after the command stating the monetary value and the volume of the total blocks.

      Command: bestpit
      The total size is 135x78x62 blocks.
      Inserting points...
      Inserted 42,120 points
        FINISHED with total monetary value of 640,326.91, and a total volume of 410,250.0 cubic units from 3300 Total Blocks

The below image shows a simple block model with the topography file.

The below image shows the same block model with the optimized pit shell .tin file. The TIN file is clipped in the front, to see into the blocks better.

Here is an image of the same block model on a Fence Diagram, with the optimum pit design surfaced drawn as an additional surface. This illustrates the surface combined with the ore, showing the optimum pit in relation to the ore. In this case, the ore is represented by the green and blue blocks, while red and orange is waste.

This image shows a transparent final pit surface in 3D on top of the block model used to calculate it. The irregular appearance of the top of this surface represents the top of the block model itself.

Shown here is another example of multiple optimum pit design TIN files shown with a block model. A fence diagram was also drawn to visualize the pit depth for each design This was run 3 times, with three different revenue calculations to see the result of the pit at various currency amounts. This command is very easy to run "what if" scenarios with different ore market values to determine the pit design.

Stratified Example

The above examples are shown with regular block models. This command can also be used to find the pit design for stratified deposits, such as this dipping coal seam model. The PRE file was used as the input files for Prepare Value Block Model. This will show how deep to follow the dipping seams and still remain profitable. Different revenue amounts may be entered to create different designs showing the mining depth based on varying revenue of the ore. Shown here are geological cross section Fence Diagrams, with the additional surface of the Optimum Pit drawn on top to see the depth to mine to. To the right are the associated pit designs, based on two dollar amounts for the coal/ore.

Pulldown Menu Location: Block Model
Keyboard Command: bestpit
Prerequisite: Value Block Model (.BM file)

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