progress in committee

'No leak' facility to store mine tailings
SOPHIE WANDEL
Thursday, 8 June 2006

STRATHALBYN - Terramin Australia has designed a Tailings Storage Facility (TSF), for the proposed Angas Zinc mine, which it believes will not leak.
Terramin is the company behind the proposal to mine zinc, lead and silver about 1km from Strathalbyn.

A TSF is required to store waste material after the valuable minerals have been extracted.

The storage of tailings was discussed in great detail by the Strathalbyn Community Consultative Committee (SCCC) at its third meeting last Thursday.

Chairman, Dean Brown, said whilst Terramin didn't give a formal guarantee, they said the TSF had been designed to combat any cause of leaching.

"Terramin indicated that the TSF being proposed was a major improvement on the original proposal.

"It is now of international standard," said Mr Brown.



The company said a large amount of the tailings would be pumped back underground to fill the void created by the mining operation.

"This would return the tailings to where they had originated and reduce the amount that remains on the surface," he said.

The TSF would cover 15 hectares with the dam wall reaching 17metres high and the dam base spreading 60metres.

Experts at the meeting told the SCCC that once constructed, the TSF would remain there forever and could only ever be used for grazing.

"The TSF would be lined with a HDPE (high density plastic) that will prevent drainage from the bottom of the TSF," Mr Brown said.

"Once the mining operation was completed, in about seven years, the top of the TSF would be covered with HDPE and sealed at the edges.

"It would then be covered with about a metre of top soil and planted with grass and low shrubs."

As a final protection, bore holes on the edge of the TSF would continue to monitor any leakage into the surrounding soil.

A water specialist assured the SCCC that even with one in 100 year rains, the water would be fully contained in the TSF.

Experts also said the TSF would be secure from an earthquake.

The next SCCC meeting is today (Thursday) at 7:30pm in the Senior Citizens Hall, Strathalbyn and is open to the public.

The meeting will deal with the visual impact of the mine, native vegetation, groundwater and similar issues.

Find the SCCC minutes at www.pir.sa.gov.au/minerals.