Selling a royalty interest with Life Estate

Have any of you dealt with this before? Do the life tenant and remainderman usually just come to their own stipulation on gets paid what?

Likely so. Life tenant is entitled to proceeds while living, but has no power to convey without the remainderman’s approval and notarized signature. The buyer can just draft acknowledgements of payment or the like that you both sign showing how much you each received, so both the sellers and buyer have proof the full amount was tendered.

Where are the minerals located?