Very unusual, but all miners experienced the same CRAZY huge trade after hours. My take is, if the volume is legit (knowing how messed up the NASDAQ et al quoting system is the volume might be false), then here is what potentially happened.
The hedge fund group that shorts commodities saw a slam dunk with the FOMC resulting in tapering (negative for silver/gold/us dollar), so they shorted all miners across the board heavily (SSRI probably went to a 10+ million short total since it tapped $10 up to Wednesday). Then Bernanke surprised them all by not bowing down to their agenda, so they were in panic mode. Some bought back immediately following the announcement, but the shrewed ones "paid off" one of the FEDees to come out and guarantee tapering in October. Hence the collapse in commodities (and the stock market)! Since SSRI held up so well during the day the marker makers must have been collecting shares to feed the hedge fund shorts, hence the 7 million share trade (SSRI's biggest block trade in its history). Market manipulation at its finest!!!
BTW, there is a zero percent change the FED tapers in October, they are in too deep! Their house of cards would be crushed worse than in 2008 if they stopped pumping printed money in to the system. Their only hope is to get the economy buzzing so soundly that nothing could topple it - there is also a zero percent chance this ever happens! So the end result is the fed continues to print money until inflation gets so crazy (al la India) that it would be worse than dipping in to a sever recession again. Which means commodities should double again within the next 3 years.