A demonstrator was arrested a protest outside of an annual Imperial Metals conference, Coquitlam RCMP say.

About two dozen protesters gathered outside the event, held at the Coquitlam Executive Plaza Hotel on Thursday morning, demonstrating against the company that owns the Mount Polley gold and copper mine.

The Cariboo region mine was the site of an environmental disaster in August 2014, when a tailings storage facility burst and water and slurry containing years of mine waste leaked into nearby lakes, creeks and rivers.

Imperial Metals' vice president of corporate affairs said the company has spent $67.4 million over four years on effort that include a complete rebuild of Hazeltine Creek.

"I think it's a world class example of environmental restoration," Steve Robertson told CTV News.

Despite the company's efforts, police knew that the conference would draw a protest and were called to keep an eye on the demonstration. A line of Mounties blocked the entrance to the hotel to keep a distance between protesters and those attending the event.

"We had no intention of intervening unless public safety was at risk or property was possibly going to be damaged," said RCMP Cpl. Michael McLaughlin.

McLaughlin initially said a protester tried to get through the police line at around 8 a.m. and assaulted some officers in front of the entrance to the hotel.

"One of our officers was attacked physically," he said.

Later, he said in a statement that the protester, a 32-year-old Port Coquitlam woman, had blocked the front door of the hotel and refused to leave.

The woman was arrested and may face charges for mischief and resisting arrest, he said.

He said that although the venue is technically private property, police typically don't enforce municipal trespass laws in the case of hotels.

"When we do have to step in is when there's a possibility of damage to a property or indeed there's an issue of public safety. In this case it was clear that there was an issue of public safety," he said.

"At least one of the demonstrators got violent, and we needed to make an arrest and stepped in at that point."

Only one person was arrested, but several others were seen being forcibly removed from the area.

Robertson described the group of protesters as a "very small" part of the population.

"I don’t believe they represent the views of the public in general. They're simply a protest group that's trying to attract attention to themselves," he said.

A statement issued ahead of the protest by the Secwepemc Women Warriors Society said that indigenous delegates and tribal allies were at the event to confront the company.

"It is clear that there are major human rights and Indigenous rights violations happening within Canada and within our unceded Secwepemc Territory," said Kanahus Manuel, a spokesperson for the warrior society.

Speaking to media at the venue later, Manuel said: "We want them to shut down. We want them to go and clean up and pack up and get out."

The statement said the group planned to advise Imperial Metals' investors of concerns around the Mount Polley mine, and the financial risks associated with investing in "poorly run companies like Imperial Metals."

The group said the Mount Polley disaster "desecrated and destroyed a sacred area," known as Yuct Ne Senxiymetkwe. They said the spill has still not been cleaned up because of the province's "shoddy mine regulations," and that the company is still discharging toxic waste directly into Quesnel Lake.

The province issued a statement about Quesnel Lake, along with an infographic that says all water containing waste will go through a mixing and filtering process reducing the levels of elements including selenium and copper. Water samples will be taken at the end of treatment, before the water is piped into the lake, which is home to a salmon habitat. 

Christine McLean, with Concerned Citizens of Quesnel Lake, said she won't drink the water or cook with it.

"Nobody knows what the long-term effect is of the actual spill and the ongoing discharge," she said.

In response, Robertson said those at Imperial Metals are confident that they're not having a measureable negative effect on the lake.

He added that although the tailings pond has been reconstructed on the same spot, the new pond is different.

"This is an extremely safe structure that has many safeguards in place now that were not in place under the previous design," he said.

The statement from the Secwepemc Women Warriors Society said the Imperial Metals conference is occurring as a United Nations group is visiting Canada to tour Williams Lake to look at the damage caused by the disaster.

The statement said the Imperial Metals conference is occurring as a United Nations group is visiting Canada to tour Williams Lake to look at the damage caused by the disaster.

"Collective Indigenous consent has never been achieved by Imperial Metals Corporation for any of their operations across British Columbia and there are multiple legal proceedings going on against the company," the statement said.

The group said its actions, which include blockades on mining roads and protesters entering Imperial Metals' downtown Vancouver office, are being carried out under the United Nations Declaration of the Rights of Indigenous Peoples. The UNDRIP was created to set out the individual and collective rights of indigenous peoples, including their rights to maintain their own institutions, cultures and traditions.

It also "promotes their full and effective participation in all matters that concern them and their right to remain distinct and to pursue their own visions of economic and social development."

Its goal is to encourage governments to work with indigenous communities to solve issues, emphasizing indigenous rights to protect their heritage and traditions.

With files from CTV Vancouver's David Molko