In February 2010, Deepwater Horizon commenced drilling an exploratory well at the Macondo Prospect (Mississippi Canyon Block 252), about 41 miles (66 km) off the southeast coast of Louisiana, at a water depth of approximately 5,000 feet (1,500 m). The Macondo prospect exploration rights were acquired by BP in 2009, with the prospect jointly owned by BP (65%), Anadarko Petroleum (25%) and MOEX Offshore 2007 (10%). Deepwater Horizon was still working on the Macondo site on 20 April 2010, when a violent explosion occurred leading to destruction of the rig and resulting oil spill. The well was in the final stages of completion at the time; its cement casing was injected and hardening, and the rig was due to move shortly to its next role as a semi-permanent production platform at the Tiber site followed by a return to the Kaskida field; squatting semi-permanently over an oil dome 50 miles off the coast of Louisiana. The exploratory work was described as "concluded" and permission had already been requested from MMS to terminate operations at the Macondo site.