interests in the Corumbá iron ore mine and the Jacobs Ranch coal mine, and completed sales of an aluminium smelter in China and the company's potash operations, for an additional estimated $2.5 billion. On 5 July 2009, four Rio Tinto employees were arrested in Shanghai for corruption and espionage. One of the arrested, Australian citizen Stern Hu, was "suspected of stealing Chinese state secrets for foreign countries and was detained on criminal charges", according to a spokesman for the Chinese foreign ministry. Stern Hu was also accused of bribery by Chinese steel mill executives for sensitive information during the iron ore contract negotiations. On 19 March 2010 Rio Tinto and its biggest shareholder, Aluminum Corporation of China Limited (Chinalco), signed a memorandum of understanding to develop Rio Tinto's iron ore project in the Simandou mine in Simandou, Guinea. On 29 July 2010, Rio Tinto and Chinalco signed a binding agreement to establish this joint venture covering the development and operation of the Simandou mine. Under the terms of the agreement, the joint venture maintains Rio Tinto's 95% interest in the Simandou project as follows: By providing US$1.35 billion on an earn-in basis through sole funding of ongoing development over a 2-3 year period, Chalco, a subsidiary of Chinalco, would acquire a 47% interest in the joint venture. Once the full sum was paid, Rio Tinto would be left with a 50.35% interest in the project and Chalco would have 44.65%. The remaining 5% would be owned by the International Finance Corporation (IFC), the financing arm of the World Bank. On 22 April 2011 Rio Tinto, its subsidiary Simfer S.A. (Simfer), and the Guinean Government signed a settlement agreement that secured Rio Tinto's mining rights in Guinea to the southern concession of Simandou, known as blocks 3 and 4. According to the agreement, Simfer would pay US$700 million and receive mining concession and government approval of the proposed Chalco and Rio Tinto Simandou joint venture. In April 2011, Rio Tinto gained a majority stake in Riversdale Mining. In 2011, the company rekindled its interest in potash when it entered a joint venture with Acron Group to develop the Albany potash development, in southern Saskatchewan, Canada. Following an exploration program, Acron in a June 2014 statement described Albany as "one of the best potash development opportunities in the world". On 13 December 2011, an independent arbitrator cleared the way for Rio Tinto,