Archie's Rule of Thumb for Mineral Deposit Economics

Archibald M. Bell (1906 - 1991) was a mining geologist and long time VP of Exploration for Noranda.  Later he was a successful consulting geologist.  Bell was an ore finder (Pamour, Timmins and Copper Mountain, Quebec).  He was inducted into the Canadian Mining Hall of Fame in 1995.  Bell is the source of Archie's Rule.

Source:  Canadian Mining Hall of Fame

Several years ago I came across a reference to "Archie's Rule" which is a rule of thumb method for evaluating the economic viability of a mineral deposit.

Simply and elegantly stated:  To be economic a deposit must have a recovered value of twice the all-in operating costs.  This allows for the covering of the capital costs.  The all-in costs includes mining, processing, refining, etc.  It assumes that the mine life will be long enough to extend over multiple metal price cycles.

Clearly not a  NI 43-101 level of evaluation, but a useful tool in evaluating mineral deposits.