The aura can only activate when the resource is about to be depleted. For example, consider a tree where each time a log is gained, there is a 20% chance that the tree is felled (depleted). When this check succeeds, the aura provides a 10% chance that the depletion will be ignored, and the tree will continue providing logs as if nothing happened. Mining rocks (and trees that provide just one log) simply provide an extra resource when the aura activates. The aura can only trigger once per resource point, unless the user changes to another resource point.