Thanks so much for responding. I reside in the Dallas Texas area and recently found out that my family has leased land that my grandfather supposedly sold back to the family. However, there is no mention of the mineral rights sold in the deed. I don't know who to contact to find out more information or where to go. Any help will be appreciated.
If your grandfather did indeed own the minerals at the time of the transfer and he didn't reserve them then they transferred to the new owner.
If you are a co-owner in the property, I would suggest you get a copy of the other owner's lease. Their lease would not affect your ability to lease your pro-rata share of the minerals, under the circumstances that you have outlined (if you are an owner).
If you are not one of the purchasers, the other members of your family own the minerals. Unless your grandfather was incompetent at the time of the sale, I don't see anything that there is for you to do.
You either bought in and own minerals or you didn't and you don't own them (based on the information that you have provided).