Maximum Active Benches

Source file: origin-blocks-setups-constraints-max-active-benches.htm

To ensure safety and reduce costs, Maptek recommends limiting the number of benches mined at a given time in each stage. The Maximum Active Benches constraint allows you to restrict the number of benches being mined simultaneously in a stage in a single period.

Note:  You cannot apply the Maximum Active Benches and Stage Bench Turnover constraints simultaneously.

Follow these steps to configure the Maximum Active Benches constraint:

  1. Click on a cell in the table corresponding to a particular pit, stage, and period.

  2. Enter a value. This will represent the maximum number of active benches in that period.

    In the image below, we are editing the maximum active benches in stage 8 of the pit Au_demo_new_phase in Period 1. This means that the maximum number of benches that can be mined at the same time in Period 1 of Stage 8 is 3.

Note:  If you enter a value of 0, Evolution will not apply any restrictions to the number of active benches in a stage in a given period.

Note:  These settings are different from limiting the total number of benches mined in a period. In other words, for this example, you can mine more than 3 benches in period 1 in total, but not at the same time.

After you generate a schedule, you can confirm that the constraint is being honoured in the schedule viewer or by exporting the schedule as a CSV file. To do this, right-click the schedule in the project explorer and select Export Schedule to CSV….

The way your spreadsheet is organised will depend on the program you are using. Follow these steps to set up your spreadsheet:

  1. Obtain a list of unique benches.

  2. For each unique bench, find the rank of the first mined block.

  3. For each unique bench, find the rank of the last mined block.

  4. At each rank, for each bench, determine whether the rank falls between the values calculated in steps 2 and 3. If the rank falls between the values calculated at steps 2 and 3, the bench is active. If the bench is active, you can add it to your tally.

  5. Graph the number of active benches calculated per rank. An example graph has been shown in the image below: