|Dead vegetation and rubbish at Urunga’s old antimony processing plant. Courtesy: Coffs Coast Advocate.|
Story: Josh McMahon
Plans for an antimony mine near Dorrigo have sparked fears the Nymboida River could become contaminated, threatening water supplies to the Coffs Clarence region.
Mining company Anchor Resources has discovered significant reserves of the valuable element antimony in the Wild Cattle Creek area, and is hoping to establish a mine in three to four years.
Antimony is used as an enhancer of flame retardants, and hardener of lead and zinc alloys for use in items such as batteries, solder, sheet and pipe metal, bearings, castings, and ammunition. Its price has skyrocketed 300 per cent to US$16,800 a tonne over the past two years, and Anchor Resources was this year subject to a successful takeover bid by Chinese minerals giant, Shandong Jinshunda Group.
Chemically related to arsenic, antimony is also toxic and has poisoning symptoms similar to its periodic table cousin. In small amounts it can cause headaches, dizziness and depression. In larger doses it damages the kidneys and liver, causes vomiting, and can result in death. Coffs Harbour councillor, Mark Graham, is pushing for his council and Clarence Valley Council to oppose any mine.
“The proposal by Anchor Resources Ltd to undertake antimony mining activities within the headwaters of the Nymboida River is of immense concern, particularly when considering that this catchment provides drinking and potable water for in excess of 100,000 residents between Yamba and Sawtell,” he said.
“Of further concern is the extremely high rainfall in the Wild Cattle Creek sub-catchment, some years exceeding three metres of rainfall per annum. It is impossible to prevent migration of toxic minerals from mines established in such high rainfall areas, as evidenced by the high levels of contamination known from the upper Macleay River, downstream of the Hillgrove mine.”
Studies have revealed that historic mining practices in the upper Macleay catchment have caused significant arsenic and antimony contamination of soil and in-stream sediments, from Hillgrove to the Pacific Ocean – a distance of more than 300 kilometres. These studies from 2001 and 2007 were quoted in a report to Kempsey Shire Council in 2009, titled the Macleay River Estuary Processes Study. Although the report stated both arsenic and antimony were toxic and carcinogenic, it said further research was required to understand their toxicity in the Australian estuarine environment.
In 2005 the discovery of arsenic in the Bellbrook town water supply, drawn from the Macleay River, forced Kempsey Shire Council to truck water 50 kilometres from Kempsey for the 540-plus affected residents. To restore use of the river for drinking water, council spent $700,000 to build a specialised treatment plant, which started operation in 2010. The contamination was attributed to the Hillgrove mine site.
Anchor Resources managing director, Ian Price, said the Dorrigo mine would operate under vastly improved practices to those carried out in the past.
“One of the key aspects is containment of any of materials from the particular site so they don’t enter waterways, or don’t go off-site. I think that’s the critical thing, and that’s proper containment of tailings in proper containment dams, and diversion of water around sites so they don’t enter the site … lots of old mining sites going back 50 or 100 years were not built with good tailings dams, and standards have developed over the past decades where those standards are much better,” he said.
Mr Price said the operation, still in its exploration stage, would also require extensive hydrological studies of the area, and an approval process involving the state Department of Primary Industries (DPI) and Environmental Protection Agency (EPA). Councils and the community would also be involved in consultation, he said.
Mr Price said there had been a mining operation at Wild Cattle Creek around 40-50 years ago that produced “modest” amounts of antimony. He admitted there were already “very very low” levels of antimony in Wild Cattle Creek – a tributary of the Nymboida River – and the cause was “probably” a mixture of mining activity and naturally occurring water flows over mineralised areas. He said Anchor would be looking further at why antimony was present in Wild Cattle Creek, and also whether it had spread to the Nymboida.
Clarence Valley Council manager water cycle, Greg Mashiah, said Clarence Valley water supplies were screened monthly for the presence of heavy metals including antimony. He said in the past 10 years there had been 210 tests for antimony, and the level had never exceeded guideline values.
Clarence Valley mayor Richie Williamson said he currently didn’t know enough about the mining project to say whether he supported or opposed it.
“We [councilors] obviously need to gather some information on the proposal. Certainly we will have a great interest because council and the community have invested a lot in water supplies for the Coffs Clarence,” he said, referring to the recent construction of the $180 million, 30,000 megalitre Shannon Creek Dam. The dam is filled from the Nymboida River.Coffs Harbour City Council is also yet to state an official position on the mining project.