May, hired by the national government, which conducted the examination in 1864; the writer Jorge Isaacs; and Mr. Juan Gomez Osío, native of La Guajira. In the 19th century small scale mining began. Cerrejón North Zone The "defunct" company Intercor (International Colombia Resources Corporation) was in its time called "The Cerrejón Zona Norte Coal Project": In December 1976, a partnership contract was signed between Carbocol S. A. (Carbones de Colombia S. A.), a state-owned firm, and Intercor (International Colombia Resources Corporation Intercor), at the time Exxon, today ExxonMobil subsidiary, to develop the north zone of Cerrejón. This contract considered three stages: exploration (1977–1980), construction (1981–1986), and production (1986–2009). In January 1999, the Colombian government extended the concession for a further 25 years, to 2034. In November 2000, the Colombian government sold its Carbocol S. A. shares (50%) in the partnership contract Cerrejón North Zone to a consortium comprising subsidiaries of BHP Billiton, Anglo American, and Glencore. In 2013, Glencore merged with Xstrata. In February 2002, this consortium acquired the remaining 50% of shares from Intercor (ExxonMobil), thereby becoming sole concessioners of the Cerrejón North Zone. In November 2002, the union of the purchased to Intercor and Carbones del Cerrejón S. A. was formalized, and the official name of the mine operator was changed to Carbones del Cerrejón Limited, Cerrejón. Cerrejón Central Zone In this zone, there are two areas under concession: The Central Deposit (El Cerrejón community) has been in production since 1981 via contracts with different companies (a Domi Prodeco Auxini consortium, Carbones del Caribe, and others). In 1995, Glencore acquired Prodeco S. A., creating Carbones del Cerrejón S. A. and then in 1997, Anglo American became involved in the business. In 2000, BHP Billiton became the third partner. The Oreganal Deposit (state-owned) was initially under concession to Carbones del Caribe by the national government. Then, in 1995, the concession passed to Oreganal S. A. which, in turn, ceded its shares to Carbones del Cerrejón S. A. in 1999. Patilla Area In 2001, after a public tender, this area was ceded to a consortium comprising Carbones del Cerrejón S. A. and Cerrejón Zona Norte S.A., which is currently concessioned to subsidiaries of BHP Billiton, Anglo American, and Xstrata. Cerrejón South Zone In 1997, after a tender process, the exploration and mining contract for this zone was awarded to the consortium now comprising subsidiaries of BHP Billiton, Anglo American, and