There were things suggested for this like a minigame. The digging could be a skill that you can train by digging and then upgrade it for money once you reach a certain level of digging.
i think that idea of leveling digging is good, i haven't played hobowars myself.. but there are a lot of web based games that are using the same general idea, it can be made different by implementing different ways to level the skill.
You need to level up before you can talk here. Go find someone to fight by clicking "Others" at the top!