As used in this Act:
"Joint owner" means a person or entity that is a joint tenant, a tenant in common, or a tenant by the entirety.
"Coal owner" means a person or entity vested with a whole or undivided fee simple interest or other freehold interest in the coal estate, but "coal owner" does not include a person or entity with a leasehold or any other lesser estate.
765 ILCS 540/10