If Teck were actually making an offer they would have had to halt the stock to explain the rise. Just the fact that they haven't means it isn't happening. They are allowed to keep negotiations secret, but not if the stock acts like the news is leaking out. Therefore, we have to assume that there is no news.
I disagree, Prospekt. I have observed many times over the years where a stock will run up in price several weeks prior to a take-over announcement. Negotiations take many weeks and months to conclude, during which time the share price will often advance substantialy even though the company may deny anything is happening. This is all just part of the game.
IMO, the CUU price advance coupled with the high volume, signals something big is coming our way. It may take a couple months, but this looks far more significant than investors accumulating due to a rise in the price of copper, or suddenly deciding we are undervalued.