(ShareCast News) - Shares in Xtract Resources declined sharply on Thursday, after the gold and copper miner reported mixed assay results from two of its South African projects.The London-listed company said the results show copper values at the Carolusberg tailing dam stood at an average of 0.21%, compared with original estimates of a 0.19% level.However, at the O'Kiep mine, the survey found the average in situ copper value was 0.14% compared with an expected 0.23%."We are still awaiting the recovery and mineralogical test work results which will enable the company to conclude if it will move ahead with the project and complete a bankable feasibility," said group chief executive Jan Nelson.Xtract shares were down 7.14% to 0.228p at 1524 BST on Thursday.