Ind. Code § 24-4-4-2

Sec. 2. Every person, firm, limited liability company, or corporation who produces, ships or sells coal in car-load lots in this state shall transmit an invoice for each shipment of coal which shall indicate plainly thereon the state in which the coal was mined, the name of the coal or the number of the vein or seam from which the coal was taken, and the size and grade thereof, which size of all grades must be designated according to the opening in the screens over and through which each such size of coal is made at the place of production.