Ann: Investor Presentation - September 2014, page-12

M&A is a big one. Specifically if BHP/RIO were buying any properties of interest (or companies).

I'd also be looking at china inventories, moreso the trends rather than the numbers month to month as they often have out-liers (and fakes).

Price trend is also a signal, in native currency (CNY??) compared to USD to see if there is stabilisation. (USD is being over-inflated simply due to lack of other options I think).

last, but potentially not least, I'd be tracking the price in coking coal price as they have often had a trailling/leading relationship throughout history.