Ann: Wide Gold Zones Continue at Namdini Project-CDV.AX, page-71

The transitional zone is a weathering feature where it's got hard reasonably fresh rock mixed up with rock weathered to clay, normally on fractures and shear zones. The depth and thickness of the transitional zone can be highly variable and can reach down quite deep then rise up on solid ground then dive down again on the next patch of fractured ground.

For mining purposes to need to treat it as fresh rock because it will need blasting and it has most of the chemical properties of fresh rock.