Restrict Mining
The Restrict mining parameter is defined to prohibit access to any area in a specific time-frame. This parameter allows you to ignore what is outside an input surface. In other words, only the material above it is available to be extracted, whether is ore or waste. This feature could be also understood as a maximum depth that could be mined at a specific timeframe.
How is it used?
Restrict Mining is commonly used to refine/optimize the mining amount of a previous surface in any period, restrict depth to a specific value which the deposit could achieve and extract the best ore in custom advances. It locks/prohibits an area due to concession rights, environmental issues, or even due to an already built stockpile, waste dump or structure in general, etc.
To sum up, the material above a Restrict Mining imported surface will be available to be mined until the specified period of time and what is inside could be mined if the blocks respect all the constraints and generate profitable results. Regarding what is outside, it will not be mined whether profitable or not.
Restricting an area for a range of time
For this example we employ the standard scenario scn21-PriceUp-RampUp-Protection300 that comes pre-installed.
In this example, periods 3 and 4 have a Restrict Mining surface as depicted below.
In the results, it is possible to identify that periods 1 to 4 do not go
beyond the limiting surface on the west portion, defined by the higher elevations of the cells (equal to the topography).
From periods 5 to 12, when the restricting surface is no longer applied, blocks can go beyong the previously constrained area.
Extracting the best material
The second example is based on the attempt to extract the best material inside the Mining_Front-FM.csv, which mapped high-grade ores in the first period as mentioned here.
Using the suitable surface file, in a scenario of Exploratory Analysis, the example was run using the set up below. A scenario without Restrict Mining was also run to have a good comparison.
As a result, the Restrict Mining surface mined the best material within the area available.
In turn, this generated different sequences as depicted below.
These examples illustrate how powerful could be user assumptions to generate suitable results or explore possibilities. The Restrict Mining parameter enables the implementation of custom geometries and operational parameters based on a smart hint imposed by the user.
Surface adjustments and constraint hierarchy!
Surfaces used for Restrict Mining might be adjusted during the optimization to respect the slope angles. Slope angles have a higher priority order on the algorithm, while the optimization is done. Therefore, less material can be mined either to correct the overall slope angle or to increase the NPV. Still, surfaces are one of the most important constraints in the hierarchy.
