Where can I find a Gas & Oil mineral rights appraiser in Utah?

Last year I sold the Gas & Oil mineral rights for land in Utah. This year I need to provide the IRS an appraisal of what that land was worth when I inherited it. Basically, a I need an appraisal to determine a "cost basis" so my tax person can help me determine what the capitol gains will be.

I don't believe that the IRS needs a complex appraisal with tons of detail (valuation?). I just need an appraisal of what it was worth the year I inherited it.

Where can I find a Gas & Oil mineral rights appraiser in Utah to help me with that. Land services?? Note - I am not an oil company, I'm an individual.