Help with valuation of mineral rights

Sold mineral rights in Tyler County WV in Feb 2018. Inherited the property and rights in 1995. There was no valuation done. Now trying to establish cost basis for taxes. Some say 0. Have seen recommendations to hire someone to provide. Please help with guidance on who or what company does this? Anyone know the cost? Thanks

If you post this in the Tyler Co, WV area, you may have better luck getting an answer. Folks may know an appraiser.