You have a much more likely chance of developing black lung if you inhale coal dust over a period of many years which is why people tend to suffer from it over the age of 50. As the name suggests, black lung really does turn the lungs black which is certainly not the way they should be. Healthy lungs are pink.
Luckily because of laws brought in a number of years ago, black lung is much less likely because the coal dust levels have been reduced from 8.0 mg. per cubic meter to only 2.0. However lung cancer is still possible. Many of those who have contracted black lung have taken their employer to court in order to claim damages. As a result there are lawyers who specialize in black lung.