Mineral Rights in McHenry/McLean County North Dakota

I am researching mineral rights left to a friend when his mother passed away. We know we have to do probate in North Dakota. Can anyone refer me to someone that can tell me the value of the mineral rights? The areas are below:

McHenry County

Township 152 North, Range 80 West

Section 19: Lots 2&3, SE 1/4 NW 1/4, NE 1/4 SW 1/4, SE 1/4 SW 1/4

McLean County

Township 146 North, Range 79West of 5th P>M>

Section 6: Lots 6(37.89), 7(37.64), SE 1/4 SW 1/4 less 8.3 acres of a 10 acre tract.