9. Mining Plan

MINEDW can simulate the progressive excavation of an open-pit mine. The simulation of open-pit excavation is performed by collapsing the elements (i.e., changing the z coordinates of nodes) in the finite-element mesh. The shape of the excavation is defined by the mine plan, usually provided as a 3-D .DXF file, and the excavation of the mine over time is simulated by interpolating between known pit geometries. There are two spatial interpolation options that can be used to calculate the new z coordinates of nodes as they are moved over time; these are explained in Creating a Mining Plan. The way in which the open-pit mine is excavated is based on either depth or volume, which is explained in the following paragraphs. Within the pit extent, a finer mesh area improves the accuracy of the simulated seepage face and pore-pressure distributions behind the pit wall.

To create a mining plan, select the “Mining” drop-down menu and then the “Create Mining Plan” function (see Figure 9.1).

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Figure 9.1 The “Mining“ drop-down menu

As described, the shape of the open pit is defined by XYZ data that may be provided as 3-D .DXF files by the mine for specific points in time. To simulate the excavation of the open pit between these known geometries, MINEDW provides two methods: depth and volume. Depth-based excavation simultaneously moves the pit surface outward in all directions, as shown in Figure 9.2. This is done by calculating the distance between two known open-pit geometries and dividing the distance by the number of time steps between the two dates associated with the geometries.

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Figure 9.2 Pit geometry when using “Depth“-based excavation

Volume-defined excavation will move the pit surface downward, rather than outward, toward the next known pit geometry, as shown in Figure 9.3. This is done by calculating the total volume to be excavated between two known geometries and dividing the volume by the number of time steps between the two dates associated with the geometries. This rate defines the volume of material excavated for each time step.

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Figure 9.3 Pit geometry when using “Volume“-based excavation

The “Create Mining Plan…” function will allow the user to combine both excavation methods when creating a mining plan only if open-pit geometries are provided.

The following sections provide detailed guidance on implementing mining plans in MINEDW, from understanding the fundamental components to creating and managing both open pit and underground operations.