Mongolia has agreed to develop its coal fields with China, as its neighbour looks to feed a booming economy and rapacious appetite for energy.
China's mines struggle to keep up with the nation's coal demand
In return for its help, China will get coal to burn in power plants, helping it tackle a power shortage that has led to blackouts and factory closures.
The deal will allow Mongolia to exploit valuable natural resources and help it finance economic expansion.
Mongolia also has large oil, copper and gold deposits.
Economic growth has picked up over the past two years, mainly driven by foreign investment from mining firms.
Growth was almost 11% last year, twice as fast as in 2003, and Mongolia's new president is looking to extend that run.
During a visit to China, President Nambariin Enkhbayar moved to reassure foreign firms that the state did not plan to take stakes in any planned ventures.
"The leadership in the country will do its best to make foreign investors feel happy about the money they are going to bring into the Mongolian economy," he said.
Mongolia is currently planning an overhaul of its mining laws to foster investment.
Foreign Minister Tsendiin Munkh-Orgil said the agreement with China was "a rather long-term project".