Mexican utility Comision Federal de Electricidad (CFE) named Mexico Constructora Industrial S.A. de C.V. to build two diversion tunnels to bypass a mudslide that blocked the Grijalva River among the dams of the Grijalva hydroelectric system.
Mexico Constructora Industrial, a subsidiary of copper producer Grupo Mexico, won the 569 million peso (US$42 million) contract in competition with five other bidders. (HNN 11/13/08)
The construction company began work in early January on the two tunnels in Chiapas State, where a landslide destroyed a village and blocked the Grijalva in 2007. It expects to complete the work in 2010.
Crews managed to dig a canal through the November 2007 mudslide that allowed partial resumption of river operations. However, CFE said the tunnels are necessary due to the magnitude of the 20 million-cubic-meter slide and the continued instability of the land in the area.
The two 14-meter-diameter, 900-meter-long tunnels are to cut through the neck of a horseshoe bend in the river, bypassing the mudslide in the river’s bend. The tunnels would carry flows of 2,150 cubic meters per second, which, added to the remaining flows through the mudslide canal, would allow total flows of 4,100 cms.
CFE said the project would ensure normal operation of the Grijalva River hydro projects, 1,080-MW Malpaso (also called Nezahualcoyotl), 420-MW Penitas (Angel Albino Corzo), 2,430-MW Chicoasen (Manuel Moreno Torres), and 900-MW La Angostura (Belisario Dominguez).