Tax implications when selling Mineral Rights in Texas

Kitchen:

As a property owner in Texas, I need some help here. I know that understanding property (surface/minerals), just surface property and just minerals is confusing to most all of us; but, to my knowledge, minerals aren't even considered as a separate taxable line item. Again, as far as I know, the CAD just considers the surface acres or the value of the surface based on their evaluations. Since I don't have any producing wells, I really don't know exactly how they access the value once production starts.

If you can shed some light on this, it would be appreciated.

Thanks