Some things you can do yourself. First, check with the appraisal district to see if there is production in the area. You can have production in the county but none near you. Second see if there is actually production in your property. Sometimes they miss an ownership (happened to my aunt) and they would owe you money.
If (A) no production in your area, and (B) not on your property, it will have minimal value. I was offered $1500 for 80 acres of mineral interests (non-producing) a cople of years ago. Turned it down. Next year was offered a significant leasing fee on the same acreage.
Bottom line is, don’t sell it and assume it has no significant value (for inheritance tax purposes). My father gathered up old minerals in east Texas in the 30’s, has made me a nice bit of change with the advent of modern drilling techniques.
You didn’t say where the minerals were, so I can’t give you any more specifics.
It’s in Beaumont.
I will follow your advice by first calling the county and going from there.
Thank you!!!