Apparently the protective gear needed to filter out the dust was not used. Education on the effects of breathing the dust was inadequate. Really, treatment shouldn't come from the government but from the mining companies themselves, who should also pass on true costs to consumers of coal. Of course, they love to mine cheap and go bankrupt, leaving the sickness and the cleanup costs to the general public.
Mining is big business here in Colorado, too. They can afford to give big money to both parties' politicians, but very little for cleanup of their pollution, in all types of mining. The miners themselves want to keep their jobs, too. Consequences down the road be damned. So many property owners have lost their land values with rigs put up on their property they have no mineral rights to, or have gotten methane in their wells, while others have gotten the insecticide/herbicide mix of nearby farms. Water mining, too, from over the divide to the big Front Range cities that should have stopped growth long ago.
The whole country has a disease, and the world, too, from not leaving the coal (and oil) in the ground, corporate and government corruption, and too many people. Black lung is a symptom.