OREANDA-NEWS. ALROSA, Sonangol (Angolan National Energy Company), and Dark Oil (an Angolan oil company) signed an agreement on prospecting and exploration for oil and gas in the Lower Congo and Upper Kwanza zones, in the basins of the Etosha, Okawango and Kassanje Rivers, and in the shelf zone of Angola. The agreement was signed in the Angolan capital Luanda for ALROSA by President of ALROSA Mr. Sergey Vybornov, for Sonangol by President of the Administrative Board of Sonangol Mr. Manuel Vicente, and for Dark Oil by Mr. Fragoso do Nascimento Leopoldino.