Perhaps the chinese company Xinwen are awaiting the outcome of the RIO/CHINALCO deal before agreeing to LNC's price for the coal tenements.
If some reports, that the deal is unlikely to go ahead, are confirmed, then the chances of LNC wrapping up a good deal would seem to increase. Refer this story in Brisbane Times-
http://business.brisbanetimes.com.au/business/rio-shares-pounded-on-deal-worries-20090514-b3yv.html
I'm not sure this deal falling through would have much of an effect on anything.
China are out to get all the resources they can at the cheapest price at the moment.
Its not like the $20billion is a huge outlay of funds. China's foreign reserves are around US$2trillion, so this would be 1% of their available assets.
Perhaps, if the RIO deal falls through, it may signal to China that they need to offer more premium than they are currently for assets (but not much more)
But, LNC is still a fairly desperate seller, whereas RIO is no longer desperate.