KGHM International’s proposed Ajax copper and gold project will be one of the first tests of the B.C. government’s approval of waste storage for large open pit mines after the Mount Polley mine dam failure in 2014.

The company, whose parent is Polish company KGHM Polska Miedz SA, plans to submit its project application early this month for review by the B.C. government. It will kick off an 180-day environmental assessment.

The $795-million project is controversial and has met with community resistance, in part, because of its proximity to Kamloops.

KGHM proposes to reduce water quantities in its mine-waste facility — and entirely buttress the large dams with rock — to increase safety at the planned mine.

However, it will not be using the dry-stacking technique to store mine waste as planned in its initial design. That method recommended by an engineering panel appointed by the B.C. government to investigate the Mount Polley failure.

Under the dry-stacking method, water is squeezed out of the finely ground rock that remains after the ore is processed. The waste rock is then transported to a storage area and compacted. The rock, which can contain toxic metals, is commonly called tailings.

The engineering panel’s report recommended the dry-stack method because there is no dam to fail, and if dry-stacked tailings shift, such as a result of an earthquake, they will not go as far as water-saturated tailings.

Among the largest spills in the world in the past 50 years, the catastrophic failure at the Imperial Metals’ Mount Polley mine released millions of cubic metres of tailings into the Quesnel Lake watershed, completely scouring a nine-kilometre creek.

Based on its own analysis of best-available technology, KGHM says it plans to thicken its tailings by squeezing out a lot of the water, increasing the solid content to 60 per cent from the 32 per cent typical of conventional mines tailings.

Source: The Vancouver Sun - see full article