Appropriate offer regarding mineral rights Richland Cnty. MT

This has a two part question/inquiry (1) I have paid the taxes on these lots in Richland County Twn/Rng/Sect 26N/57E/10 S2S2,NESE Twn/Rng/Sect 26N/57E /15 N2NE, SENE for about 14 years. Is there a law that states after a certain amount of years that the entire property is mine? (2) I have PRP Holdings wanting to negotiate a lease, they are offering $7,800.00 for unstated years, no mention of royalties. So what is a reasonable offer?