As the heroes pass the lands, they will be contacted by the representants of a mining company, that have experienced a spree of bad luck in their mine recently. The heroes, considered crafty in this area*, are supposed to get rid of the evil spirits that are undoubtly the cause.
1. It is something supernatural indeed, a spirit of earth, the ghost(s) of a deceased miner(s), a leprechaun that moved underground (hey, treasure!), an insulted permonik or something else. Annoyed by the mine or something else, prepare to chase little folk that can teleport or become invisible through tight tunnels - though a riddling contest is also not out of question.
2. The digging has uncovered something else - a form of magical mineral is ignored among the ore, or in fact pure magic starts to seep from the depths. Reacting with the minds of simple miners, it is only a question until the strange effects grow in size and someone is really harmed. There is opportunity for wealth as risk, proceed with care.
3. You don’t need magic, when good old intrigue is never far among humans. And one of them would like to have a better position, while others stand in the way… see below for more details.
*) Some adventurers and their reputation will this suit just fine, others won’t - and if desired, more intrigue can be conjured - was it only misinformation that led to their hiring? Little money? Desperation? Or a greater purpose? (The mines owned by the barony, this is an innocent way to test them before using for something else, etc.)
A little more detail
It is a copper mine of the old style, so picture walls out of wooden boards, horses drawing cart trains on crude tracks, and plenty of poor miners doing their hard work. The tunnels will follow the veins of ore, vertical and horizontal if possible, but often going in any direction that seems profitable.
Gormain - is a push-man (directs one of the ‘trains’ of carts) over fifty, he has lost a few toes on the right foot in an accident a few years ago, it still haunts him that he could loose the whole leg. Sensing his approaching old age, he would at last want a reward for his many years of faithful service… and may go too far while aiming higher. His additional job of mine maintenance offers easy opportunities.
Nodem - the current wheelmaster, almost seventy, plans to retire soon. A wheelmaster controls the large wooden wheel that pulls loads and people out of the deep; it is a position of prestige and decent pay, requiring a feeling for the dangers of the mine and the strength of ropes, reserved for senior miners.
Traspan the doctor - quote “It is a good day when I have nothing to do.” It is universally known that he is not a ‘real’ doctor, as he has left the school too soon, but people still call him that way. He does minor paperwork if little is going on, but has deep knowledge of fractures and blunt trauma wounds, and plenty of practice with lesser wounds.