to take profits is a wise move indeed whatever stock you are trading/investing in.I think there is a bit of manuevering going on atm by hedge funds and it goes like this,,,,,,short the physical(zinc),send the stock down.Buy the stock@cheaper price.Close short position,physical price rises,stock rises,sell the stock.
Simple to do if you have big $s to play with!. All this being said I am strongly long ZFX.
Regards