NZ Orphan mine site taken into care

Tanya Piejus (New Zealand) One of New Zealand’s most contaminated sites, the Tui Mine near Te Aroha, is to be cleaned up. The New Zealand budget for 2007 confirmed that NZ$9.88 million was available for the two-year project. The orphan mine site sits on the western flank of Mount Te Aroha, one of Waikato’s highest peaks. In Maori legend, the spirit of Te Mamoe, son of a Bay of Plenty chief, caused a stream of crystal water to flow from the heart of the mountain. However, that stream has become blighted by acid and metals from the abandoned mine workings and is now almost devoid of life. Fig. 1. Polluted water at Tui Mine Tui Mine’s story began in 1967. Norpac Mining Ltd opened it in order to extract metals, including copper, lead and zinc. The mine prospered and the company found several thousand ounces of gold and silver among the ore.  However, unacceptable levels of mercury in the ore soon proved to be the mine’s undoing. The company buying the ore pulled out in 1973 and, two years later, Norpac went into liquidation. Tui Mine was abandoned. Mining equipment was removed for reuse at other sites or was sold for scrap. Left behind was a large pile of larger ore pieces, along with sand-sized crushed ore (tailings). This was dammed to prevent it slipping down the mountainside but, through neglect, the tailings dam became unstable. In 1980, the Hauraki Catchment Board had to build a gravel embankment to stop … Read More