GHD | Oceana Gold New Zealand Ltd. | 12552081 | Waihi North Project 22 reducing the exposed areas open to rainfall infiltration, the volume of leachate from this source reduces. Over time, with the completion of capping, air will be excluded from the rock mass reducing sulphide oxidation and an improvement in leachate quality is expected. This has been confirmed based on observations from TSF2. Toe drains carry mainly groundwater that wells up below the embankment structure, but may contain some rock seepage. Initial toe drains pick up seepage from the starter embankment. Seepage flows from all drains are pumped to the WTP in a single pipe, hence it is the water quality of the mix of different drain types that is important in determining required treatment. Seepage flows from TSF1A and TSF2 are used in the processing plant or treated for trace element and trace ion removal at the WTP prior to discharge to the Ohinemuri River.
RkJQdWJsaXNoZXIy MjE2NDg3