The mammoth Casino mine proposal is being bumped up to a full panel review, it was announced this morning.

It will be the first panel convened under the Yukon Environmental and Socio-economic Assessment Act since the legislation came into effect in 2005.

“The decision to move the project to a panel review is based on two criteria set out in section 58 of the YESAA legislation,” Ken McKinnon, an executive committee member with the assessement board, told a press conference.

“A, the project involves technology that is controversial in Yukon, and B, the project might contribute significantly to cummulative adverse environmental or socio-economic effects in the Yukon.”

The open-pit, copper-gold project would be the largest mine in the territory’s history, with daily production estimated at 120,000 tonnes a day, or 10 times the daily production of the abandoned Faro lead-zinc mine at its peak.

The tailings dam would stand 286 metres tall, approximately 15 times the height of the law courts on Second Avenue and more than half the height of the CN Tower in downtown Toronto.

It would be the third-highest in the world, and would span 2.5 kilometres.

The Casino property is located 150 kilometres northeast of Carmacks, in the heart of the Klaza woodland caribou range.

In addition to the 80 kilometres of the existing Freegold Road leading west from Carmacks through the caribou range, another 120 kilometres of new road would be required.

McKinnon and staff explained the primary concerns are the proposed tailings dam and storage facility and the additional impact the project would have on the caribou herd.

The Casino Mining Corp., a subsidiary of the Western Copper and Gold Corp., submitted the proposal to the assessment board’s executive committee for review two years ago.

Following 18 months of active review, including requests for more information from the company, the executive committee determined two weeks ago it needed to elevate the review to the panel level. It informed the company on Wednesday.

McKinnon said the primary difference between a panel review and a review by the executive committee is the degree of public involvement and scrutiny. A panel review dictates that public hearings must be held, he explained.

Assessment board lawyer Mara Pollock noted a panel is also a quasi-judicial body with the power to subpeona witnesses, call evidence and issue orders.

Under legislation, the panel has 15 months from today to complete its work, not including the time it takes for the company to answer any additional information requests, Pollock explained.

McKinnon said responses to date have not provided the level of information sought by the committee, the Yukon and federal governments and First Nations.

The three-member panel will be chosen from the assessment board’s board of directors, which includes McKinnon and executive member Dave Keenan, who was also present this morning.

The board of directors is made up of seven members, though there are two vacancies currently.

In a statement this morning, Western Copper and Gold indicated it recognizes how a project of Casino’s size requires a thorough assessment.

Having the proposal bumped to a panel review now removes the uncertainty of having it bumped up later in the process, the company indicated.

“We appreciate that a mine of this significance requires all key aspects to be thoroughly evaluated,” Paul West-Sells, Western Copper and Gold’s CEO, said in a statement this morning.

“We look forward to working with Yukoners to ensure the project moves forward in an environmentally and socially responsible way.

“We remain confident that the Casino project is a great asset for Yukon that will provide benefits to Yukon communities and First Nations for generations to come.”

The company has estimated the cost of construction of the mine at $2.5 billion, but has also stated that level of financing is not out of line for a project of this significance.

In today’s release, the company points out a 2013 feasibility study “shows favourable economics, even at today’s low commodity prices.”

The proposed dam raised alarm bells with many parties early in the process, including the Little Salmon-Carmacks First Nation, which hired an international engineering firm to assess the proposal.

Scores of major issues were identified by the firm, including the concern that there is nothing in the world to compare the design to, as well as how stability and permafrost foundation might be affected by a warming climate.

The mine life is currently estimated at 22 years.

Assessment board staffer Nathan Aasman explained the requirements of the tailings dam and tailing storage facility – until the end of time.

• the storage facility guarded by dam would hold 950 million tonnes of tailings, 20 per cent or 191 million tonnes of which would be potentially acid draining, all protected by a blanket of water;

• the storage facility would also hold 650 million tonnes of waste rock; and

• the facility would cover a total area of 11 square kilometres.

“This is the technology the executive committee has determined is controversial,” Aasman explained.

He said the project would also increase the impact on the Klaza caribou range.

Currently, Aasman explained, the footprint on the Klaza range of existing mines, roads an trails, including the Mount Nansen Mine, is estimated at 7.75 square kilometres, in a range that measures 10,800 square kilometres.

The zone of influence from existing activity, the zone that caribou might avoid because of mining activity or vehicle travel, is 810 square kilometres, he said.

Aasmon said the Casino mine project would add 27 sq. km. of footprint, and increase the zone of influence by 1,000 sq. km.

The assessment board has notified federal Indigenous and Northern Affairs Minister Carolyn Bennett that it may require additional funding now that the Casino project has been elevated to a panel review.

McKinnon said officials don’t have an estimate of how much the panel review will cost, but he suggested $1 million to $2 million.

The cost, he suspects, will be driven largely by how many communities will ask to have public hearings held in their areas, and he expects there will be a few, right up to Old Crow.

McKinnon said the assessment board has so far spent $500,000 on consultants to review the Casino proposal, including retaining Dr. Norbert Morgenstern, the man who headed the investigation into the disastrous failure of the Mount Polley tailings dam in B.C. in August 2014.

Some of the information the executive committee doesn’t have is the extent of environmental damage that would be caused by a catastrophic failure of the proposed Casino dam, he said.

McKinnon said while the tailings at Mount Polley were not toxic, the tailings at Casino’s proposed storage facility would be.

The mine site drains into the Donjek, White and Yukon rivers, he pointed out.