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Britannia cleanup holds water

Flooding is as much a part of the legacy of Britannia Beach as mining. In 1925 a catastrophic flood killed 37 people.

Flooding is as much a part of the legacy of Britannia Beach as mining.

In 1925 a catastrophic flood killed 37 people. A flood of similar magnitude occurred in 1991 when Britannia Creek filled with gravel and jumped its bank near the same place as the ’25 flood. And there are fears flooding could happen again.

A one in 200 year flood; an event that can happen when there are rain storms coupled with very high tides, could occur in Britannia. There’s also the potential for a substantial rock slide in Jane Basin.

These hazards were on everyone’s mind at a third public meeting updating the Britannia Mine remediation project held at the Britannia Beach community hall on May 23. Discussions included flood risk assessment, the location of a water treatment plant and sludge storage options.

Flood risk assessment in Britannia Creek includes maximum probable flood and debris flow analysis. Other activities include site-wide monitoring of surface water conditions in Britannia Creek, Jane Creek, Furry Creek and Mineral Creek.

Peter Healey, an engineer with SRK Consulting in Vancouver, brought the audience up to date on what’s been done underground with regard to safety.

"We had to rehabilitate to make it as safe as we possibly could so people could work in there," Healey began.

Work being done inside the mine includes installation of flow monitoring equipment.

"At the plug itself, we installed displacement gauges to measure any minute movement of the plug when we’re putting pressure on the plug," Healey explained. "There’s a piezometer installed in the host rock just in front of the plug to monitor ground water pressures that could build up within the rock itself as we increase pressure behind the plug. There is also a valve that is a key component controlling the amount of water that flows through the pipe."

The flow rate through the mine is estimated to reach 420 litres per second when the freshet hits in mid-June. The out-flow arrangement can currently handle up to 800 litres per second.

"Water enters up at the Jane Basin area and discharges down at the 4100 level," Healey continued. "During the freshet the system controls its own flows."

Two plug tests are being conducted at the mine.

"The first test was run from March 26 to May 13," Healey continues. "We took that up to 102 metres above the plug and, we drained it down to 20 metres. We’re currently maintaining it at 20 metres for safety purposes."

The second test will involve turning a valve off about a week after the freshet, allowing the waters to rise up to about 250 metres above the plug located 300 metres above sea level. As soon as the water hits the 250-metre level the water will be brought back down to a controlled discharge.

"Will we get one million cubic metres of storage at 250 litres per second?" Healey asks. "That’s what we’re trying to find out."

Options to control flooding of Britannia Creek include a set-back dyke that was originally proposed to be built by the B.C. Museum of Mining site. A sediment basin in the upper fan is the option recommended by water management consultants. This option would involve opening the stream channel in the upper half of the fan.

Doug Lee, a project engineer with amec Inc., in Vancouver, suggested that several sites had been identified for the location of a water treatment plant. One site would be in behind the mining museum property.

"It’s to the east of the museum buildings and the concentrator," Gerry O’Harra, a principle of Golder Associates and project manager says.

A second location for the water treatment plant at the lower level might be behind the ball field. The other two sites could be at the 4100 level.

"At this stage, we’re identifying issues with the sites," Lee reported.

The findings will be presented at another public meeting about the middle of June.

There are three preliminary options being explored for sludge disposal.

"There are a series of on-site options that involve looking at Jane Basin as a permanent sludge disposal site on the property," O’Hara continued.

The on-site option could include a staging area near the 2,200 foot level or lower for storage when Jane Basin is snow-bound. There are several old pits in the Jane Basin that could be used to accommodate an estimated six or seven thousand cubic metres of sludge material per year.

The second strategy is to take the sludge to a commercial land-fill. A third option would be an off-site land fill designed specifically to take this material.

A detailed site investigation will continue to be carried out to assess any risks to people and the environment in Britannia. Up to 10,000 parts of copper per billion have been found in the groundwater from the tailings area of the mine, mainly in the south part of the fan that includes an area across the highway from the Concentrator Mill.

During question period that followed a presentation, Joseph LaSorsa, a spokesperson with J L Development in Santa Cruz, California, asked about the consequences of a plug failure.

"The water would go down into the area," Peter Healey answered, adding that the likelihood of the plug failing is very low.

A question was also asked if a plug failure would be catastrophic.

"You would have plenty of warning if there was a plug failure," Healey answered.

Healey maintains that there is virtually no risk of failure of the rock around the plug that might result in a catastrophic release of water.

"That’s reassuring," a resident of Britannia said in response. "One of the concerns of the community was the release of water."

R.H. Roberts, Assistant Deputy Minister with the Ministry of Water, Land & Air Protection, indicated that a strategy is being formulated to provide future funding for the Britannia Mine project.

"The government identified a contingent liability of $45 million," Roberts said, "but the bottom line is that our job is to try and do this without dipping into public funds to actually achieve it."

Roberts said there are a number of options to provide long term funding and that the time has come to address those options. One of the factors that has to be looked at is what the development potential of the site is, what revenues might be expected from that development and what share of those revenues would be available for the sustainability of the site.

"We’ve got some money to get cracking," Roberts reiterated. "Now we’re looking at ways we can provide long term funding."

Pam Tattersfield, a director in electoral area D in the Squamish-Lillooet Regional District and a 10-year resident of Britannia, is pleased with the remediation project and consultation with the community.

"I feel confident that the cleanup will get done," she says.

The property may then become ready for development, which could be a mixed blessing for the community.

"There is the threat we could be relocated," Tattersfield acknowledges, "but, I’m hoping that the community could be seen as an asset by the property owner."

Cutlines:

pics 1-5 - A small but well informed group of Britannia Beach residents discussed progress of the Britannia Beach remediation project at a public meeting on May 23/02.

pics 6,7,8 - The location of a water treatment plant and sludge storage options were two main issues discussed at a public meeting updating the Britannia Beach remediation project on Thursday, May 23.

pics 9,10 - One of the concerns of the community is the release of water

contact:

- Gerry O`Hara, principle, Golder Associates and spokesperson for the project.

tel: (Main) (604) 296-4200.

cel (604) 728-7940.

- R.H. Roberts, Ministry of Water, Land & Air Protection

tel: (250) 387-9877