The Joint project includes the Hugo North Extension and Heruga deposits. Rio Tinto is managing the construction. 
Rio Tinto files a complaint against the IMF, which consequently delays the release of the first IMF bailout payments
This phase includes the Hugo North lift 1 underground mine and the Southern OT open pit
The finance agreement for a USD 4.4 billion underground expansion of the OT mine (OTUMDFP) is signed in Dubai. Not only is it largely publicly financed (including the IFC and EBRD), it also explicitly consolidates the terms of the 2009 Investment Agreement. Read more
In response to a possible tax increase, dispute over costs, and increasing political will to renegotiate the Investment Agreement, Rio Tinto halts Oyu Tolgoi operations and lays off 1,700 jobs. 
As Rio Tinto acquires a majority stake in Ivanhoe Mines in January 2012, the name of Ivanhoe Mines is changed into Turquoise Hills Resources (TRQ) as of August 2012. Read more
Rio Tinto wins in an arbitration case from Ivanhoe Mines, which tried to prevent a Rio Tinto take-over.
An ‘Amended and Restated Shareholders Agreement’ (ARSHA) is signed by Erdenes, Ivanhoe Oyu Tolgoi, Oyu Tolgoi Netherlands B.V., and Oyu Tolgoi LLC (formerly known as Ivanhoe Mines Mongolia Inc.)
The first phase of Oyu Tolgoi open pit construction begins.
Rio Tinto becomes the operator of Oyu Tolgoi and with Ivanhoe seeks to complete an international project-finance package of up to USD 3.6 billion.