Price dropped because key players (banks) were short silver and needed to get out of their positions. How do you do that? You raise margin requirements, time it with a convenient server "failure" and use the news of the nomination of a new Fed chair, who's supposedly going to lower rates, as cover.
Western futures markets are rigged. It's just a casino where the house always wins. Shanghai's price didn't budge. In fact, it's risen another $10. Western markets can't stop the storm. All they can do is try and delay the inevitable.