Lunch redo your calculations using a different date. I see that they were all pretty well the same price on Mar 12, 2009. Do the same comparison over the last 3 months!

Anyone ever recall seeing a time and or cost dimension plan for this mine. A proper one would be updated regularly as timelines are either achieved or missed. Most engineers and project managers use them religiously to ensure they can achieve the plan! Checkpoints are set up to gauge progress along the way and regular daily, weekly monthly reviews to give early warning of trouble that needs attention before it jeopardizes the schedule.