Digging it out is harder work than you estimated. [The character doing the digging has to make a L2SR on STR (25–STR). You can try as many times as you want, but for every failure there is a 50% chance (flip a coin) of being discovered.]

If you succeed at digging it out, you can claim your price, or if you tire of digging you can just give up. (But remember that you cannot try to dig again.)

(Note: This page was created by Mattias Wikström, because it was missing on the original site. Hopefully this humble substitute fits the adventure just as well.)