To protect our valuable water resources and the environment, Sandfire has designed a Cemented Tailings Facility (CTF) that improves on established practices by allowing for a solid, dust free facility. After filtering and squeezing out most of the water, tailings mixed with cement will be permanently stored in a 100 mil High Density Polyethylene (HDPE) double lined facility in a non-flowable state. There will be a pump back system placed in the bottom of the facility so that the small amount of water squeezed from the tailings as it sets up as well as any precipitation occurring on the facility is pumped into a double lined process water pond. As an added precaution, a water runoff catchment pond is placed below the tailings dam to test any water below the facility making sure it is working properly.
As a result of new tailings legislation in Montana to protect the environment in 2015, the cemented tailings facility is designed for a 1 in 10,000 yr. maximum earthquake event and a maximum storm event for the area of 22 inch precipitation on 11 inches of snow melt (1.25 years’ worth of precipitation for the location)
This new system ensures that a rare, event like what happened at the Mt. Polley sub-aqueous tailings facility in British Columbia can never happen here.
The Black Butte CTF design will be approved by three independent tailings engineers with at least 10 years of experience in accordance to Montana’s new 2015 Tailings Legislation creating the most stringent tailings regulations in North America