Good post Highgrader.
In my opinion the following are not only conservative assumptions but too conservative:

"Review for additional ore in phase 1. The feasibility study used a cut-off grade of 2.0 grams per tonne gold for the initial high-grade oxide phase of production."

"Assumptions: low metals price scenario -- Au: $600, Cu: $1.50, Zn: 50 cents, Ag: $8. Preproduction capex -- $250-million (June, 2008, including contingency)."

Just about everyone uses one gram per ton as a practical assumption of a resource. The higher the price of gold gets relative to cost of energy and labour the lower that gram cutoff gets.

The metal prices are also very conservative.
Gold =$800/oz., Copper =$2, Zinc =$0.75 and silver =$12 is to be expected. The current metal prices are fairly low due the the global economy and the PM prices ( Au & Ag) are additionally at manipulated low levels. These can not be sustained for too much longer.
So it is quite reasonable to expect at least 25% more return from this mine ( just my ball park assumption).