Topic-specific hearings on the proposed New Prosperity Gold-Copper Mine continue through the week until Aug. 1 in Williams Lake.
From Thursday through Saturday geology and hydrogeology, acid rock drainage and metal leaching were discussed. For Monday and Tuesday aquatic environment is on the agenda.
Last Thursday evening Taseko Mines Ltd. gave its geology and hydrogeology presentation.
“What we’re proposing is not unique,” said project manager Scott Jones. “Open pits are often in close proximity of large water bodies. Our pit design is supported by extensive site-investigation data. Our overall pit slopes fall within the range of defined open pit mines in B.C.”
From an environmental assessment aspect, there is no geotechnical interaction with the mine and Fish Lake, Jones said.
“No one pays more attention to the safety of the pit design than the operator,” Jones said, adding pit designs are subject to the regulatory mine act and have to be approved by the chief inspector of mines.
New Prosperity Mine would have a four-phase pit, he explained.
“This method of phasing is driven by economics and provides the opportunity to gather important information before you get to the final wall.”
Taseko has a level of confidence for the purposes of hydrogeology, said consultant Greg Smyth on behalf of Taseko.
“The tailings ground water will not adversely affect Fish Lake or the Taseko River,” Smyth said.
For several decades there’s been a large volume of drillings across the site that have helped inform the design, and additional drilling will help with developing the detailed design if the mine is approved, Smyth said.
On Saturday, Dr. John Kwong with Natural Resources Canada said the proposed project does not pose significant environmental impacts to derive from acid rock drainage, provided Taseko is diligent in carrying out all necessary monitoring and adopting appropriate adaptive measures or treatment of any contaminated release.
“Timely reporting and analysis of monitoring results to identify deteriorating trends is recommended as a requirement to advance the proposed project,” Kwong emphasized.
On behalf of the Tsilhqot’in National Government, Geoscientists Dr. Kevin Morin, raised several concerns about sources of water contamination at the proposed mine site.
“Any disturbance at a mine site comes with potential geochemical sourcing for water contamination,” Morin said. “The full impact of the New Prosperity Mine on water quality has not been properly determined.”
He said concentration level predictions in the Environmental Impact Statement are too low.
“This is a daisy chain effect of source terms, pathways and receptors,” Morin said. “Getting it wrong on the source terms means everything below it is wrong.
Water treatment would be necessary as an integral part of the mine plan, not an option Morin insisted.
Aquatic environment discussions will continue through Tuesday, followed by discussions on terrestrial environment Wednesday and human environment Thursday.
All sessions are open to the public. Audio and written submissions are available on the Canadian Environmental Assessment website.