Unsolicited Offer - where to start

Family received an Offer to Purchase Oil & Gas Interest from Lincoln Energy. I don’t know what info is pertinent to ask questions, or even what questions to ask, but… The offer is $500/nma and says the mineral interest is currently estimated to contain 580 nma. (Is this what she owns alone or is this the total nma between any and everyone else who owns some of this tract?). She really doesn’t know what she owns, it was passed down to her several years ago. She says she been receiving $50-150/yr in recent years.
Several tracts are listed…Amite County, MS T1N, R4E Sec 2: sw4 nw4 Sec 2: ne4 nw4 Sec 3: all

T2N, R4E S29: e2 se4 S29: n2 ne4 S41: sw4 nw4 S30: se4 ne4 S24: nw4 ne4

T1N, R6E S32: w2 sw4

I’m sure the offer is low??? How would we value this? Is there Any other info needed that I’ve left out? Any help would be very appreciated.