Handing over mineral rights

I see this is not a currently active group but I will post here anyway, 2022, with hopes of a helpful response. What is a good way to transfer my life estate in mineral rights (Coleman County)to my grandson owner of the relevant property now, while we are both still alive. I would like to avoid “gift” and a 709 IRS filing. Should a dollar value be necessary how are such mineral rights appraised? Thank you vey much for your thoughts.