When I did detailed calcs I used 10% plus interest for the lands not directly involved in the BFS. I didn't have an accurate cost for Mess Creek and assigned 30 million. (Work and purchase at today's price.). For the Port eg. That is cost plus savings plus interest. I credited some of the inferred results and the drilling on a sliding scale based on distance from the main deposit and number of holes in an area. (Got a rough idea of what was in an area.) I used the silver to predict the distribution. That's how I arrived at the north being richer in silver. It was obviously a very long process that was built up as we went.