RE:Some Additional ThoughtsOne correction: You would still need a higher bond interest rate to match returns at a given discounted value for a mine. That would be the discount rate + compounded profit from operations. So, at a given NPV discount rate, you need to add an additional percentage matching discounted life of mine profit. It might take a bond of 10% or 12% to match a mine discounted at 6 or 8%. You can also calculate this from undiscounted cash flows. Additional risk from mining justifies the higher return. If interest rates ever rise to high levels, this would act to constrain business, putting downward pressure on metals prices as available supply soars. So, there is an inverse relationship between NPV project valuation, and global interest rates. It's definitely not a problem in the foreseeable future.