Thechipsareallin - that 58% silver recovery from a copper deposit is not bad at all. I looked at some gold mines with silver resources and the recovery rates can be much lower. Here is an example from the Detour Lake Mine:

"The metallurgy of the Detour Lake deposit is simple as the gold is mainly native and easily liberated allowing excellent recovery and for a relatively coarse grind. The gravity circuit is expected to recover approximately 30% to 40% of the gold. The remaining gold in ore is sent to cyanidation followed by carbon in pulp (CIP) gold recovery. After carbon stripping, the gold will be processed through electro-winning cells prior to gold pour. The overall gold recovery is estimated at 91.2% with silver recovery estimated at 48%."

So we are better than Detour Lake, good enough for me.