08/11/2014 04:23 EDT | Updated 08/11/2014 04:59 EDT

B.C. Mine Spill Aftermath Could Cost $200 Million

Jonathan Hayward/CP

As the water use ban is partially lifted for the B.C. Cariboo region hit by a tailings pond spill from a gold and copper mine, the focus turns to the possible long-term effects and cleanup.

The tailings dam at the Mount Polley Mine, owned by Imperial Metals, failed last Monday, releasing millions of cubic metres of water and silt into surrounding lakes, creeks, and rivers.

Aleksandra Bukacheval, an analyst at BMO Nesbitt Burns Inc., estimated the cost to Imperial Metals at $200 million, reported the Financial Post. She called the event "extremely negative" for the company.

Legal damages could double that amount. Notice of a class-action lawsuit was filed last week on behalf of shareholders who bought stock after August 2011, reported The Vancouver Sun.

The newspaper reported Imperial Metals has $15 million in property and business interruption insurance, which is likely not enough to cover cleanup costs. In comparison, it cost hundreds of millions of dollars to clean up the 1998 Los Frailes mine waste dam collapse in Spain.

Over the weekend, the engineering company that designed the Mount Polley tailings pond issued a statement saying it warned the project and the province about potential risks, reported Global News.

It highlighted a 2011 letter it sent that said: "The embankments and the overall tailings impoundment are getting large and it is extremely important that they be monitored, constructed and operated properly to prevent problems in the future."

Imperial Mines is creating a temporary dam to try to stop the ongoing leak, but it could take three weeks to build a berm to halt the further spillage of water and debris from the tailings pond.

Initial tests from the province's environment ministry suggest water in some parts of the area is drinkable.

The newest round of tests show water samples taken from Polley Lake on Aug. 7 is very close to "historical levels" before the tailings pond breached, the government said.

More testing will be done before a water-use ban for the lake is lifted.

Some First Nations are concerned about the safety of eating fish caught in area waterways after two reports of sickly fish.

With files from The Canadian Press

Photo gallery Mount Polley Mine Tailings Pond Breach See Gallery