To everyone bitching that the author is using "Black Lung" when coal isn't involved, coal mining isn't the only type of mining that causes Pneumoconiosis. It's just the most famous due to coal minings explosive popularity relatively close to the modern age (large mines started developing in the 1800s, compare gold and silver's much lengthier history), and coal's innate properties that make it more likely to cause the disease. While I will admit that mercury poison would be more fitting, Pneumoconiosis can be caused by any profession that involves inhaling a lot of dust particles unprotected, and I doubt these miners have good mining conditions and knowledge of such things.