First time DM, concepts, input

... a very rich vein. The greedy tribal leader ordered an expansion of the mine, and executed two underlings who were too cowardly (as he saw it) to oversee the mission before giving the job to Sifdax (Wizard3, PC stats), who shared his greed. With some guards (Warrior1, x5), he leads two dozen miners (Expert1) to the site. This goes unnoticed by the human village for weeks, until a farmer runs into ...