Collect gold and bomb your way deeper into the mine. Use bombs to excavate the mine. The mine material deteriorates with each blast until it vanishes and you can get through. The blocks are visibly damaged with each bomb so you can see how much more damage you need to do. Each piece of gold you collect is worth points, larger gold pieces are worth more points. Collect as many points as you can, and don't use your bombs frivolously. They can be found in the mine too, but you only have so many of them.