Protesters take aim at South Australian mining department's handling of St Kilda mangrove die-back TueTuesday 2 People wore black armbands during the "vigil" for the St Kilda mangroves. ( Share Print text only Cancel A "vigil" has been held at Parliament House in South Australia for 10 hectares of mangroves that died due to a salt mining mishap north of Adelaide. Key points: Community leaders and the Opposition have questioned the Government's handling of the situation There are warnings that many more mangroves remain at risk, with hypersaline water still leaking into the area The aquatic trees surrounding the popular St Kilda Mangrove Walk, along with 35ha of salt marsh, are believed to have been killed by leaking salt brine from nearby gypsum ponds.