Personally I like anything that is over 1.5% cu (Copper), with decent intervals (esp. if it is open at depth);
Re; Gold (au) - anything over 3.5gpt/au (depending if it is vein structure (like a quartz reef), or smaller amounts than 3.5gpt/au in sulphides (which means small amounts, but over a big area);
Re; Silver (ag) - not too sure on silver but the numbers have to be big ie; north of 800.
The above are just my own interpretations of what I tend to look for based on a quick read of an announcement and from what I have gleaned since I have been in the market.
