Acacia Mining maintained strong cost discipline in the financial year ended December 31, achieving an all-in sustaining cost (AISC) of $905/oz, well below the guidance range of $935/oz to $985/oz, interim CEO Peter Geleta said in a statement on Monday. He added that the company had returned to free cash flow generation in the second quarter of the year and sustained that throughout the second half of the financial year, ending the year with a net cash position of $88-million.