Production Constraints

Introduction

The Production tab allows the user to set period ranges and its corresponding production limits. This functionality allows the user to consider 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. At the training presentation on this page, you can check the NPV formulas used.

1.1. Period Ranges

Figure 1 presents a panel where the user can define period ranges.

The Period Ranges feature allows the user to vary correspondent variables over time (see the last section of this page) such as:

The user is able to edit only the field To. Subsequent periods will have their From field adjusted automatically.

1.2. Timeframes

Figure 2 highlights the timeframe panel, where the user can choose different values for their projects. The values are used to deliver more accurate sequencing and have their values attached to a yearly basis calculation. It is possible to select a predefined value or to input a customized one.

In this example, we used a timeframe of 1 year, meaning that each generated period on this sequencing represents one year.

1.3. Production Limits

Figure 3 highlights the Production panel where the user can define limits for any destination added.

In this example, we have the following limits:

Process 1: 30,000,000 t
Dump 1: <unlimited>
Total: 60,000,000 t

These limits are being considered from Period 1 up to the <end> of the life of mine.

1.4. Add/Remove Intervals

Figure 4 highlights buttons to add and/or remove intervals, which are shown in rows in Figure 4.

1.5. Multiple Periods

Figure 5 presents an example where multiple periods were added.

A user has defined two period ranges as follows:

From 1 to 4
From 5 to <end>

For the first range, the user clicked on the field To (A) and set a value of 4. Automatically, the field From (B) of the second range, changed to 5.

The user can repeat this process to fragment the life of mine, and change parameters over time, as much as required. In this example, production limits increased 100% for Process 1 and 50% increase in Total from Period 5.

Notes

The example from Figure 2 shows that the user does not need to set an explicit limit for all destinations available. In this case, Dump 1 has an <unlimited> upper bound. This means MiningMath will have enough flexibility to reduce process throughput – and increase dump tonnages up to the Total limit – whenever it finds this is a solution that increases the project's NPV. For users willing to have more control and reduce this flexibility, simply define a limit for each destination.

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