Tailings bad news, concludes study
Richard Gleeson
Northern News Services
Yellowknife (Feb 02/01) - Something must be done to stop the erosion of old Giant Mine tailings into Back Bay, concludes a new study.
"Reclamation of the beached tailings area is recommended to minimize further migration of tailings solids into Back Bay," says the report commissioned by the department of Indian Affairs and Northern Development.
The study offers four options for action. Three involve removing some or all of the tailings and preventing further erosion while the fourth proposes construction of a break wall.
DIAND is developing a proposal, but any action requires approval from the Mackenzie Valley land and Water Board, said Neil Thompson a member of the Royal Oak Project Team.
The report written by the Deton' Cho Environmental Alliance also recommends further studies.
A key piece of the puzzle is learning the rate at which metals and arsenic leach into the lake. An estimated 375,000 tonnes of tailings has been on the shore for as long as 50 years.
Waves have carried tailings into the lake and the fine-grained material, a bi-product of the gold refining process, now covers the bottom for 100 metres out from the beach.
Analysis of water from the tailings beach revealed concentrations of antimony, arsenic, cadmium, copper and zinc that exceed Canadian guidelines.
The lone sample of Back Bay lake bottom had high levels of arsenic, zinc and antimony.
Mercury levels and the acidity of the rocks were within federal guidelines.
The report was 11 months in gestation. It was delayed by a dispute between DIAND and the consultants over contract details.
