Instructions
Enter Rivet Ravine for the first time to enter the first area of Mole tunnels. The main area and first tunnel are both open when you first arrive.
Explore the tunnel to have the next one the sequence become available for you to venture into. There are five of these tunnels in total.
Pay one of the miners for the right to dig for fossils in the Pay To Dig tunnel. This tunnel is on the far left of the Ravine.
Finish the game to unlock another series of tunnels, along with the secret Mole tunnels. The secret tunnels hold the strongest Vivosaur fossils, and can be found by climbing the rope ladder on the far right of the Ravine's lobby.