[Cobre and BHP Billiton signed a letter of intent to explore Botswana's first-class copper and silver mines] On September 23, Cobre, an Australian mining company, announced that it had signed a letter of intent for first-class copper and silver mines with BHP Billiton's wholly-owned subsidiary. The two sides will conduct exclusive negotiations on the substantial income joint venture agreement of Cobre's Kitlanya West and East copper mine projects in Botswana. Before reaching the agreement, Cobre participated in BHP Billiton's Xplor exploration plan, which also provided funds for the recent seismic survey of the Kitlanya West project.