Full Mineral Rights or NPRI?

My grandfather bought mineral interests in Texas back in 1950. We have been approached by someone who says he wants to buy our NPRI. But when I read the original deed, it sure sounds like it's for full mineral rights.

It reads as follows:

Know All Mean Buy These Presents:

That (the grantor) has and by these presents does grant, bargain, sell, convey, set over, assign and deliver unto (the grantee) the following, to wit:

One-fourth (1/4) interest in and to all of the oil, gas, salt, sulphur, potash, and other minerals of every kind and character in and under and that may be produced from the following described lands situated in XXX County, Texas, to wit:

Being XXX acres of land, more or less, and being further described as...

(The grantor) is the owner of an undivided 1/2 mineral interest in the above described 160 acre tract more or less, and they are hereby conveying to (the grantee) a full 1/2 of their 1/2 in all of their minerals and to all of the oil and gas and other minerals in and under, that may be produced from the above described land, being XX acres, more or less, that is hereby conveyed.

Together with the right of ingress and egress at all times for the purpose of mining, drilling and exploring said lands for oils, gas, salt, sulphur, potash and other minerals of every kind and character, and removing the same therefrom.

And the said above described lands being now under, embraced in and covered by an oil and gas lease originally executed in favor of (the grantee) and now held and owned by (the grantee) it is understood and agreed that this sale is made subject to said lease, but this sale covers and includes one-fourth (1/4) of all the royalty of every kind due and to be paid under the terms of said lease, from the above described land.

It is agreed and understood that one-fourth (1/4) of the money rentals covering the above described land which may be paid to extend the term within which a well may be begun under the terms of said lease is to be paid to the said (grantee) and in the event that the said above described lease for any reason becomes cancelled or forfeited, then and in that event, the lease interests and all future rentals on said above described land, for oil, gas, and mineral privileges shall be owned jointly, the grantee herein, owning one-fourth (1/4) interest in all oil, gas and other minerals in and upon said land, together with one-fourth (1/4) interest in all future rents.

This sale is made for in consideration of the sum of $XXX cash in hand paid, the receipt of which is hereby acknowledged.

TO HAVE AND TO HOLD, the above described property, together with all and singular the rights and appurtenances thereto in anywise belonging unto the said (grantee), his heirs, successors and assigns forever, and we do hereby bind ourselves, heirs, executors and administrators to warrant and forever defend all...

So what do you think? NPRI or full deed?

This is a grant of full mineral rights, not just NPRI. The right of ingress/egress (or basically the right to operate), and the right to participate in bonuses are dead giveaways. An NPRI owner does not have the power to drill wells on the land burdened by their interest, and they do not share in lease bonuses. The right to actually grant leases, which is called the executive right, is necessarily implied from those two rights.

Your rights are more valuable with the executive rights attached to it, so you should be sure to clear this up with the party offering to buy your rights before you agree to anything.

Thanks Andrew. I'll post here again to report on what happens.