It would help to know why the miners are going down so sharply at this time? As to who is selling, and why such big volumes, most likely it's the usual suspects: Goldman, JP Morgan, various hedge funds; maybe some central banks as well.
Seems like an organized campaign to flatten gold and silver miners, then later buy them for next to nothing.
FWIW, Faber likes mining stocks, "Faber continues to utilize gold as a large part of the portfolio and he does like mining stocks. He also advocated for foreign stocks, particularly the markets in the Ukraine, Vietnam and China."
'maybe some central banks as well."
You think central banks invest in miners? Wow, just when you think the intelligence level on Yahoo has hit bottom.
They may be buying physical gold and governments may have a stake in domestic mines and sovereign wealth funds may invest in nearly anything, but no central bank is going to start trading shares in mines or buy ETFs or buy lottery tickets.