OyuTolgoi copper-gold mine project in Mongolia is jointly owned by the Government of Mongolia (34%) and Turquoise Hill Resources Ltd / Rio Tinto Group (66%). The project is estimated to involve a capital expenditure of $11.3 billion, and is expected to have a significant impact on the Mongolia Economy over the next several decades. This case study analyzes the internal and external economic environment of the stakeholders, and its impact on the project. Interactions amongst the stakeholders are also discussed to assess the influences. It is extremely important to note that this project is peculiar because the Government is a stake-holder, and the size of the project is significant for the Mongolian economy. Hence, various elements of the project can be treated as part of both the internal and external environment. Therefore, the interplay between the stakeholders has overlaps, and cannot be strictly slotted into categories. The case study brings out the impact of global macro-economic environment, commodity prices, political environment of Mongolia and financial & operational performance of Rio Tinto on the past, present and expected future performance of the project. It is evident that successful & efficient production of copper-gold from the mine is critical for both Mongolia and Rio Tinto. For this, the risk factors need to handled with tact and care so that there is optimal utilization of resources and equitable distribution of benefits.