RE:crazy swings on the spot price for zinc...It's all Chinese money. You can kind of track the action in the commodity exchanges from their opening hours. And then, (sort of) predict/follow the swings.
Take last night, Sunday, for example. 7pm eastern standard time (EST) is 1am Monday in London when automated trading begins on the LME. It's also 8 am Monday in Shanghai. (The Dalian Exchange keeps Shanghai time and has trading from 9-11:30am and 1:30-3pm Shanghai time--same hours as the Shanghai exchange.)
So, at 7pm EST your intrepid Chinese maniac(s) logs on and starts the day with a bang, jacking metals up to the sky as they are the speculative flavours of the day. By 8:30pm EST (Sunday!) we have been treated to the first multi-dollar upward jolt in Zinc. It's now 9:30am in Shanghai and the action in the Dalian/Shanghai exchanges is just getting started. Higher highs. It's the middle of the night in London.
Basically, they bull the metals all day long while we stay up late too stunned to go to bed until, at 2am EST we go to bed with spot zinc at $1.32. At 7:30 am EST we fall out of bed, check spot zinc--it's still at $1:32---and get to work when at 10am EST we take a coffee break which is when the Chinese say 'I'd better unwind these long positions and get some sleep' and there we are watching zinc fall off a cliff to $1.27. This coincides with the close of trading in London where it is 4 pm.
Monday 7pm EST repeat cycle.