Yeah all fair points- gold miners are very hard to value and as...

Yeah all fair points- gold miners are very hard to value and as goldnerds correctly points out there is a big discrepancy between reported operating cash costs and actual costs (when you factor in exploration and development). Even for the best miners the total cost to mine an ounce of gold is close to 1000USD.

I think the best way to actually see what the real costs are is to go back to basics and look at the cashflow statements. If you look at MML and RMS- they are absolutely raking in the cash, whereas IGR with reported cash costs of 550/ounce is actually cashflow negative. Interestingly, SAR's announcement today has shown rising operating costs (most likely due to high AUD). With each quarterly, the really important figures are increase in cash and receivables not the cash costs!

The calculations I've done above are pretty rough, but if you have a big enough margin of safety you are pretty safe. Going for the lower cost producers at a significant discount to value or worth will generally insulate you (even with a big fall in price of gold).