Drilling Commencement

Aminex PLC 11 May 2005 Aminex PLC Drilling of Well GU#35 on South Weslaco Prospect, Hidalgo County, Texas, USA Aminex PLC ("Aminex"), the oil and gas company listed in London and Dublin, today announces that its US operating subsidiary Aminex USA, Inc. has spudded South Weslaco Well GU#35 in Hidalgo County, Texas. The well is the first of up to four gas development wells planned for the current year at South Weslaco. Target depth is 9,000 feet (2,740 metres) in the Frio Sands and there are prospective gas horizons in the range 7,000 feet to 9,000 feet (2,130 metres to 2,740 metres). Partners are Aminex USA, Inc (25%), Activa Resources LLC (25%) and Stalker Energy LP (50%) (operator). Aminex Chief Executive, Brian Hall commented: "GU#35 is part of an ongoing programme to build up new gas production by drilling up proved undeveloped reserves in Texas to replace the production from the ageing Vinton Field in Louisiana which was sold in late 2004. The result of the well should be known within one month". 11 May 2005 Enquiries: Aminex PLC Brian Hall +44 (0) 20 7240 1600 Simon Butterfield College Hill Jim Joseph +44 (0) 20 7457 2020 This information is provided by RNS The company news service from the London Stock Exchange