The treasure lies at a depth of more than 100 yards. That's a job for the Mad Digger!

Pickaxe — your main tool. Upgrade it to dig faster and more efficiently.
Oxygen Tank — allows you to stay underground for a long time. Upgrade it to increase the time limit.
Drill — a big drill which allows you to pass the first layers much faster and collect more resources.
Grenade — has a small radius of action, but all the blocks blown up by a grenade never go waste, and if they contain something useful (resource or oxygen), you will take it.
Dynamite — has a large radius of action, it is very convenient when you need to quickly cover a considerable distance. Dynamite has a drawback when compared to a grenade: it destroys everything in its path, and if you blew a block with a resource, you won't get it.
RadWater — water with moderate radiation dose. It makes the Digger 10 times stronger and faster while active.