Personally I think it is a number of factors.
The rise in price of PM's is certainly helping and the SP is trading somewhat with their rise and fall.
The recent update that highlighted production increases and future expansion numbers has opened some eyes to the fact that these veins can be milled profitably and suddenly this vast resource is viable. I think that is extremely important.
Thirdly the redicilously low SP was a no-brainer. The recommendation by Tayler seemed to also coincide with the increase in SP and success breeds success. I bought a lot of shares because of the strenth and depth of the trading. That has most certainly led to some short covering , although I am sure there is still a sizable short position. There have been a couple of blatent attempts to nip these rallies but they have been met by strong buying.
I picked up a couple thous shares this morning on the drop. We just need silver to explode and the shorts will be forced to cover and we could be back to the merger price quickly.