I would be surprised if they didn't have multiple mines going. Dwarves seemed like a self reliant bunch and I doubted they would import vast quantities of metal and other resources they could get from the earth themselves.
The town had mine cart rails running down the street. The buildings were short and stout stone buildings merged with metalwork. The doors had intricate metalworking designs on them. Some of the houses even had minor gemstones embedded in the doors.