Unfortunately if the correct property interest was never transferred to the trust prior to your mother's death then you may need to start probate proceedings in order to be appointed Personal Representative and then execute a corrective deed. The correct mineral rights sound like they were still owned by your mother, not by you or her trust, at the time of her death. You want to make sure you do this correctly in order to actually transfer legal ownership of the mineral rights.
All the best,
I hope this helps. If you think this post was helpful, please check the thumbs up (helpful) tab below. Thank you!
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.