A treasure chest stands to the left of the quarry and fills as you mine: a quarter, half, three quarters, full, and overflowing when you win.
Each broken tile bursts into five little gems of its color that arc across into the chest and pile up on its heap. The imps don't carry sacks any more.
After mining, imps walk back down to a hole in the ground at their lane's spot and drop out of sight. Waiting imps in the lanes and slots now face away from you.
The chest and holes are placeholder drawings until their art arrives.
TREASURE!