Negative WAG Stockpile Example: Previous Period WAG, No Shift Definition
Analyte Calculations
There are three stages for the calculation of retained analyte quality on WAG stockpiles that go negative.
Stage 1
If a stockpile goes negative after a reclaim transaction, the Assume Retained analyte quality is maintained at the values prior to going negative.
Stage 2
If a new stacking transaction occurs but the stockpile balance stays negative, the Assume Retained analyte quality of the stockpile balance is assigned the weighted average of the stacking analytes from the previous configurable number of periods. However, if no shift is defined, the Assume Retained analyte quality of the stockpile balance is assigned the last available stacking analytes.
Stage 3
If a new stacking transaction makes the negative stockpile balance positive, the new stacking transaction analytes are assigned to the stockpile balance.
Example
The following table displays the transactions on a WAG stockpile. The configured Negative Method is Previous Period WAG, and no Shift Definition is selected. The Date Option is Start Of Shift, but is unused because there is no shift definition.
Stage 1 begins with Transaction 4, when the stockpile balance becomes negative. The stockpile's analyte quality for iron was 63.4% after Transaction 3, so that value becomes the assumed analyte quality for the reclaim transactions in Stage 1.
Stage 2 begins with Transaction 6. Although this is a stacking transaction, the quantity is not enough to make the stockpile balance positive. Because no shift is defined, the assumed analyte quality for iron is the same as the input analyte for that transaction: 62%.
Stage 2 continues with Transactions 7–12. The stacking transactions assume the analyte quality from the input analyte. The reclaim transactions assume the analyte quality from the previous stockpile balance.
Stage 3 begins with Transaction 13, which is the first stacking transaction that makes the stockpile balance positive. The sampled analyte quality for iron on that transaction is 62%, and this becomes the analyte quality on the stockpile balance.
Contributor Calculations
There are three stages for the calculation of retained contributor values on WAG stockpiles that go negative.
Stage 1
If a stockpile goes negative after a reclaim transaction, the Assume Retained contributors are set to the original contributors for the current and any subsequent reclaim transactions.
Stage 2
If a new stacking transaction occurs but the stockpile balance stays negative, the Assume Retained contributors are calculated as the weighted average of the stacking contributors from the previous configurable number of periods. However, if no shift is defined, the Assume Retained contributors of the stockpile balance are assigned the last available stacking contributors.
Stage 3
If a new stacking transaction makes the negative stockpile balance positive, the new stacking transaction contributors are assigned to the stockpile balance.
Example
The following table displays the transactions on a WAG stockpile. The configured Negative Method is Previous Period WAG, and no Shift Definition is selected. The Date Option is Start Of Shift, but is unused because there is no shift definition.
Stage 1 begins with Transaction 4, when the stockpile balance becomes negative. The stockpile's contributor values were A:50%, B:50% and C:0% after Transaction 3, so those values become the assumed contributor values for the reclaim transactions in Stage 1.
Stage 2 begins with Transaction 6. Although this is a stacking transaction, the quantity is not enough to make the stockpile balance positive. Because no shift is defined, the assumed contributor values are the same as the input contributors for that transaction: A: 0%, B: 0%, C: 100%.
Stage 2 continues with Transactions 7–12. The stacking transactions assume the contributors from the input contributors. The reclaim transactions assume the contributor values from the previous stockpile balance.
Stage 3 begins with Transaction 13, which is the first stacking transaction that makes the stockpile balance positive. The sampled contributor values on that transaction are A:100%, B:0% and C:0%, and these become the contributor values on the stockpile balance.
