yes, you could investigate locally cached chunk data, and this is not something we will work around without massively increasing network and cpu costs and changing a large part of the game (we wont do it), but you still have to manually mine the blocks of course, no magic break behind walls.
but we dont really care too much about this, since the atlases already show you were the resources are too (not in so much exact detail, but still, not a big secret)