Grassy Mountain review panel hears safety arguments

·6 min read

The public hearing for the proposed Grassy Mountain mine continued hearing witnesses’ evidence and cross-examination during the week of Nov. 3.

The scheduled topic items included geology, damming safety, accidents and malfunctions, industrial waste and waste management, and effects on the environment like climate change.

Dam right

Much of the discussion focused on the mine’s four surge and four sedimentation ponds.

Surge ponds capture water from precipitation that passes under the waste rock deposits that may be tainted with selenium. Sedimentation ponds collect water for treatment and removal of suspended solids, aided by coagulating agents called flocculants and letting particles naturally settle.

Explaining the nature of the ponds, said Benga’s vice-president of external relations, Gary Houston, was important because many opponents of the mine point to the danger posed by tailings ponds.

Tailings ponds typically hold toxic materials left over from industrial processes involving water. Benga would not be using tailings ponds because the mine would mechanically dewater during its processes.

Most of the ponds point toward Blairmore Creek, though two sediment ponds are near Gold Creek. The pond locations are needed to catch water flow from the mine, thus minimizing the risk of erosion and landslide.

Proposed dam designs for each pond have followed guidelines set by the Canadian Dam Association as well as Alberta Dam and Canal Safety Directive. After construction, the Alberta Energy Regulator would provide regular monitoring.

Opponents of the proposed mine project, however, were concerned Benga had not studied the consequences of a pond failing nor completed an emergency response plan.

Though the mining company said creating these plans was subject to the project’s approval, critics responded that understanding Benga’s disaster processes was integral to fully analyzing risks associated with the project.

“How can this panel make an informed decision about the risk of your project having impacts on the environment in the context of these sedimentation and surge ponds if, in fact, you haven’t done that study yet and you haven’t presented that evidence at this hearing?” asked Mike Sawyer, legal counsel for the Timberwolf Wilderness Society.

“How can we make that decision? Are we just supposed to trust you?”

Mr. Sawyer also said the proposal lacked any assessment of how dam failure would affect populations of the westslope cutthroat trout, which contravened expectations set out by the Species at Risk Act. Particularly important information missing was data on how the fish would react to the flocculants and sedimentation in the ponds next to Gold Creek should a leak occur.

Issues with dam failure, responded Mr. Houston, were easy to exaggerate since even opening a floodgate would be classified as dam failure.

Any effect on the trout from a pond bursting, he continued, would be reversible and only an issue in the short term and would be accounted for in Benga’s planning.

“There is a process in place for dealing with these risks and we’re going to abide by that process,” Mr. Houston said.

Even with Benga’s assurances that the dam design would mitigate flood risk, expert witnesses asked to participate by the Government of Canada said the dam designs were based on an inaccurate model of how much the average annual precipitation would increase over time.

Dr. Ann-Lise Norman, an atmospheric physicist from the University of Calgary, said the issue was the scale used in collecting precipitation data. Benga’s calculations relied on too large an area as scale: a 90-kilometre area was used when industry standard is 10 kilometres.

Data collection from Sparwood and Pincher Creek, Dr. Norman continued, was at locations too low in elevation to accurately predict what amount of precipitation should be expected at the Grassy Mountain site.

“Higher spatial resolution is critical,” she said. “It produces more accurate results, and I think Benga’s maximum precipitation for Grassy Mountain was based on too low an elevation.”

Nothing earth-shaking

On top of concerns the mine would be susceptible to storms and flooding, local residents and environmental groups said approving the project would increase the risk of grass and forest fires.

The main fear expressed was that distributed layers of coal dust on vegetation in the area would create a volatile situation should a wildfire start. Additionally, critics said Benga had not adequately addressed the risks associated with coal seam fires or coal dust explosions in its environmental assessment.

Coal dust, however, was not viewed by Benga as a major issue as minimal amounts of coal would be stored at the site and coal transportation would all be done in covered chutes.

“The biggest source of dust will be the road dust,” Mr. Houston said.

The company would also have its own fire-protective equipment and trained staff on-site.

Worries daily blasting at the mine would contribute to seismic activity in the area were viewed as negligible.

Dr. John Cassidy, an expert on seismic hazards from the University of Victoria, noted only 11 earthquakes had been registered within 50 kilometres of the mine site in the last 40 years. The largest quake in that time was measured at a magnitude of 3.2 on the Richter scale.

719 mining blasts had been registered in that same time frame, supporting Dr. Cassidy’s experience that industrial blasting had never been seen to affect seismic activity in an area.

The potential for blasting to cause landslides, however, was acknowledged as a risk inherent in the Grassy Mountain area. Benga had put forward in its assessment mitigation measures like annual ground condition inspections — increased after major precipitation — and a ground-monitoring program.

Natural Resources Canada had reviewed the measures and found them satisfactory.

Although the effect of blasting on Turtle Mountain was not considered significant, Mr. Houston said no specific discussion with the Alberta Geological Survey had occurred in regard to monitoring the mountain. Benga was also unsure if the AGS was monitoring Turtle Mountain for seismic activity.

Given the lack of experience Benga as a company had in mining operations, the MD of Ranchland, said lawyer Michael Niven, did not have confidence in the company’s procedures and capacity to respond to emergencies.

The gap was one Benga was willing to bridge, said Mr. Houston.

“We could talk about the drilling and blasting procedures and the safety measures put in place, the scientific methods for monitoring the blasts,” he said. “Those are all things we’re prepared to discuss if that’s a topic that the MD would like us to come and talk to them about.”

To this point, Benga has not had any discussions with the MD of Ranchland concerning the project.

Sean Oliver, Local Journalism Initiative Reporter, Shootin' the Breeze