Cash-strapped Mongolia's deal to expand the $6.5 billion Oyu Tolgoi mine is a big step towards stabilising its economy, but as it waits for the investment boost to feed through it is leaning on once-feared China to help shore up its finances.The landmark agreement with Rio Tinto to resume construction of the underground copper mine ended a two-year dispute during which foreign investors had shunned the country and slumping coal exports left it short of reserves.
