Borisdog,
being in a sedimentary environment, the host rocks are comparatively soft-as you would have noticed at Cadjebut. This equates to a bucket load of shot crete for OHS requirements-much more than the lower standards in the US.
Excellent quality concentrate could be expected as per Cadjebut but the grades are crud.
Hence no-one racing out to spend the hundreds of millions to sink a shaft to undergo mere feasibility work at AB.
Cheers,TAS
