From what I understand there is more than one way to evaluate a resource company but reserves in the ground is the most frequently used. The reason is that they go through waves of development where they spend a lot of cash and their P/E increases and of production where they then reap the rewards and their P/E falls.

What I look at is

#1 - Management - How much experience.
#2 - Mine location, life and political risk.
#3 - Current market cap per ounce in the ground.
#4 - Current capital possition - will they need to do a financing soon.
#5 - Warrant/options, prices and expiry dates.
#6 - The notes on thier last Q report for anything that looks funny.