Operating intermittently as determined by site water levels, the plant treats a mix of tailings seepage and mine contact water to produce treated effluent fully compliant with site requirements. This includes selenium below 2 ppb and sulphate below 950 ppm to ensure that conditions for passing bioassays are met. By-products of treatment are a solid gypsum and stable non-hazardous iron oxide-selenium residue suitable for onsite disposal.