When material within a block is scheduled and is placed onto a dump or a stockpile, the characteristics of that material may change. For example, low grade material may be placed onto a waste dump and thereafter it may be considered to be waste. Similarly, low grade material may be blended with high grade ore in a stockpile to produce a high grade product.

Within XPAC, these materials will typically be modelled as activities. So, in some cases the activity number of the source material may be different to the activity number of its destination. The way in which materials change between the source and the destination is controlled by activity mapping.

Activity mapping consists of defining where a value from the source record will appear in the destination record. In a situation where low grade ore is being dumped in a waste dump, you may wish to map the low grade ore tonnage to the waste tonnage. In the resulting waste dump the two values will be added together to give the total waste tonnage in the waste dump.

Each dump and each stockpile can have its own activity mapping. If no activity mapping is assigned to a dump or a stockpile, then it is assumed that the activity of the source material is the same as the activity of the destination material.

Once the materials have been combined in a destination record, they cannot easily be separated. In a case where low grade ore has been mapped to high grade ore in a product stockpile, only the resulting product can be scheduled from the stockpile and it will be a combination of the low grade ore and high grade ore delivered to the stockpile. When the stockpile is re-scheduled, it will become the destination and it will be made up of a single activity called high grade ore. While the low grade ore and high grade ore delivered to the stockpile may be stored in separate parcels, they will all be part of the same activity when they are re-scheduled. The only way the low grade and high grade ore being mined from the stockpile can be reported separately is through interrogation of the output paths by an XCM.

Activity mappings can be created and then assigned to any dump or stockpile. A single activity mapping can be assigned to multiple dumps and stockpiles. However, each dump or stockpile can only have one activity mapping assigned.