Production Constraints
MiningMath allows the user to set period ranges and its corresponding production limits. This functionality allows the use of options such as pre-stripping, production ramp-up, prices changing over time, among others. It is worth mentioning that the discount rate on MiningMath is already applied in the first period. For more information on NPV calculation click here.
In the Scenario tab, under the Production option the user can define period ranges.
Such ranges allow the user to vary variables over time such as:
- Production limits
- Limiting surfaces
- Average (blending) and sum constraints
- Economic values
- Geometric constraints
The Timeframe Panel allows users to set values for their projects, ensuring more accurate sequencing. These values are applied to calculations on a timeframe basis. Users can either select a predefined value or input a custom one to suit their specific needs.
For example, in this case, we selected a timeframe of one year. This means that each generated period in the sequencing corresponds to a single year.
In the Production panel the user can define limits for any destination added.
In this example, we have the following limits:
- Process 1: 30,000,000 t
- Total: 60,000,000 t
- Dump 1: <unlimited>
These limits are being considered from Period 1 up to the end of the life of mine.
Multiple period ranges based on different timeframes can also be added added.
In this image, two period ranges were defined as follows:
- From period 1 to 4, yearly productions
- From period 5 till the end, each period represents 3 years production.
This approach allows you to fragment the life of the mine and adjust parameters over time as needed. The Add Range and Remove buttons, located at the bottom-right corner, make it easy to add or remove period ranges.
Explicit limits per destination
Explicit limit for all available destinations are not always required. For instance, the dump can be assigned an <unlimited> upper bound. This provides MiningMath with the flexibility to adjust process throughput and increase dump tonnages (up to the Total limit) whenever it identifies this approach as a way to maximize the project’s NPV. For users who prefer greater control and want to restrict this flexibility, simply define a specific limit for each destination.
On the other hand, the production capacity fields for processes require a defined value. If unlimited production is desired, you can simulate this by entering an extremely high, practically unreachable number (e.g., 9999999999999).
