Hazardous locations are a process design decision. The electrical rules just tell you what to do with the results for installing electrical equipment. Few electrical engineers know and understand explosive gases, dusts, etc.
Might want to also look into a mining engineering company too since a lot of them near your area do business all over Eastern Kentucky where they have to do this for systems running on coal.
Haven’t lived there for over 15 years so most of my contacts probably moved or retired.