How much does the extra land add to ARV?

[Jose Guevarra]

Hey Guys,

I'm trying to comp a small 665sqft house on a 1.71acre "L" shaped lot. The very few comps out there don't have nearly that much extra lot space.  How much does that extra land add to the value? 

Also, the owner thinks there's value in the mineral rights. This house is on a residential lot(property report doesn't give zoning) and located in CA. What's the likely hood that anyone could even extract gold?/oil? from that lot without a fight with the city or neighbors?

Thank You!