Federal law prohibits mining if there's too much dust in the air. Today, miners use personal air samplers to test dust levels at regular intervals. Also, large fans on the surface force explosive gases out of mines, and dust is controlled by wetting coal or spraying limestone on the walls. In sufficient quantity, these could pose environmental problems. Some of these by-products may contribute to acid rain, though the exact causes and possible solutions are still being studied by scientists within and outside of the industry.
Mining companies plan the reclamation process before digging.
In many cases, land is left in better condition than before mining started. This acid is now being chemically removed before the water is discharged into streams. Slurry pipelines require large amounts of water. But lakes created during land reclamation can help replace some of the water used. Fine ash particles fly up into the air when coal burns.