BEIJING, May 3 (Reuters) - Landlocked Mongolia sits on vast quantities of untapped mineral wealth and analysts say it could be one of the fastest growing economies of the next decade, as well as a key investment target for global mining giants.

The $5 billion Oyu Tolgoi project, jointly owned by Ivanhoe Mines and the Mongolian government, will be the world's biggest copper mine outside Chile once full operation starts in 2013. Plans are also under way to develop the Tavan Tolgoi coking coal mine, the world's biggest untapped deposit of its kind.

But foreign companies and investors are watching to see whether the country's fledgling democratic government can build the infrastructure required, maintain stability, improve the rule of law and -- most crucially -- negotiate its way through the geopolitical pressures exerted by its two massive neighbours, Russia in the north and China in the south.