Percent Models

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Formatting Percent Models

1. Defining the lithology

Although this is not a mandatory step for the optimization process, the lithology can be defined considering:l in terms of tonnage.

The tonnage of a block.
The value of a block.

Figure 2 shows the information of a block that could be classified as:

MX, if considering the greatest parcel in terms of tonnage.
MX, if considering the greatest parcel in terms of tonnage.

Figure 1: Illustration of a block with different parcels.

Figure 2: Block information divided into lithologies OX, MX, PM, Waste.

2. Density

MiningMath calculates tonnages based on [block size × densities]. The average density of a block should be equal to the weighted average based on lithologies and their respective percents.

3. Recovery

Recoveries should also be calculated considering the amount of material recovered from each parcel of the block.

4. Economic Value

The economic value is calculated considering the amount of material recovered from each parcel, along with their respective revenues and costs.

There are two ways to calculate the economic value of a block:

Without dilution (Option 1): only ore parcels feed the plant (Figure 3).
With dilution (Option 2): the entire block feeds the plant (Figure 4).

4.1 Option 1 without dilution

In this case, the Economic Value for the process will consist of Revenue – Costs, where:

Revenue refers to the ore parcel (70%).
Processing Costs refer to the ore parcel (70%).
Mining Costs refer to the entire block (100%).

As MiningMath will process the entire block, input a greater value for the process limit, assuming the algorithm will feed the plant with the remaining parcel of waste (30%).

Create auxiliary columns to track and control tonnages limits of ore, waste, and any specific lithotype you want (Figure 6).

Ignore default production charts and consider the tonnage ones being used as Other Constraints.

Figure 3: Strategy for economic values considering only ore feeds the plant.

4.2 Option 2 with dilution

In this case, the Economic Value for the process will consist of Revenue – Costs, where:

Revenue refer to the ore parcel (70%).
Processing Costs refer to the entire block (100%).
Mining Costs refer to the entire block (100%).

In this case, as there is dilution, the processing limit inputted in the interface, should be the real plant limit.

Again, auxiliary columns will provide further control of tonnages for each parcel (Figure 6).

Figure 4: Strategy for economic values considering ore and waste feed the plant.

Figure 5: Example of calculations for a block composed of different lithotypes and its respective economic values assuming no dilution and diluted material.

5. Other Constraints

Create auxiliary columns for tonnages of each lithotype, as demonstrated in Figure 6.
During the importation, set them as Other.

This step will make you able to track and control tonnages of each material.

Figure 6: Example on how to track specific information of a block.

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