Africa-focused oil and gas explorer and producer Aminex is selling its US arm to AIM-listed Northcote Energy and privately owned Springer Oil and Gas for $5m.Aminex, which has two operated discoveries in Tanzania, is selling a US portfolio which mainly includes the Shoats Creek field in Louisiana and the Alta Loma field in Texas.The $5m comprises US$150,000 in cash, US$350,000 in Northcote shares and a production payment of US$10 per barrel until a total of US$4,5m has been recovered.It plans to use the proceeds to pay off part of its loan and to provide more working capital.Northcote and Springer plan to invest a minimum of US$1m in the assets in the next 12 months to increase production.Aminex plans to focus on Tanzania, where it said first gas production from its Kiliwani North site would begin in early 2015.Shares in Aminex closed down 0.02p or 1.7% at 0.88p while Northcote's stock dropped 0.04p or 4.3% to 0.9p.PW