An extension has been granted to the period for commenting on the proposed changes to water licence for the Minto Mine.

The Yukon Environmental and Socio-economic Assessment Board's (YESAB's) Mayo office issued the extension Jan. 13, the day of the original deadline.

Parties now have until Feb. 3 to comment.

The extension was sought by the Yukon government and other parties who said they needed more time to put together submissions on such a complicated application, since a large portion of the comment period ran through the holiday season.

Capstone Mining Corp. is seeking higher allowances of metal content in the water it discharges into Minto Creek, which flows into the Yukon River. The company maintains the higher levels will still meet Canadian standards.

It is also proposing to physically restructure water management at the mine site by diverting run-off from snow and rain around the site and directly into Minto Creek.

Diverting the natural run-off prevents the water from entering the mine site, so eliminates the need to treat it, under the principle "keep clean water clean,” says the 165-page application.

The Minto Mine is also seeking permission to increase the amount of water it uses to 1,000 cubic metres per day, and to up production from 3,200 tonnes per day to 3,600, in order to use up the full capacity of the mill and maximize efficiency.

Once the YESAB makes its decision, the mine will still be required to have its application approved by the Yukon Territory Water Board, a process which will include a public hearing.

The application to the YESAB indicates its water treatment system is not able to sustain discharge standards at times when runoff is high.

The Minto Mine has required three emergency amendments in the last two years because of above-average volumes of snow and rain, the application points out.

It also says the background information collected by the previous owner to support the original water licence issued in 1996 before the project fell dormant for nine years does not accurately reflect conditions at the mine site today.

Both the Selkirk Renewable Resource Council and the Yukon Conservation Society have expressed deep concern with the mine's request for higher discharge levels for copper.

An increase in the allowable copper content is particularly worrisome since high levels of copper are known to reduce or destroy the ability of salmon to navigate, say the submissions to the YESAB from both the society and resource

council.

The resource council also requested an extension in the comment period to put together a more comprehensive response.

The conservation society, while accepting the mine's "keep clean water clean” approach to water management, doesn't agree entirely with the proposed management structure.

The Minto Mine, the society notes, is proposing to redirect all runoff outside a defined boundary around the mine site.

The society, however, suggests water which runs across ground that has been disturbed by heavy equipment or exploration activity – the airstrip, for example – should not automatically be considered clean.

In its submission to the YESAB, the Department of Fisheries and Oceans indicates the proposed changes to the water licence will not have an impact, as long as the Minto Mine takes three steps to protect Minto Creek:

• install effective sediment and erosion control measures;

• maintain natural creek flows through the year; and

• ensure water entering the creek will not alter the natural temperature.

In its application, the mine notes that fish studies indicate Minto Creek is a not a salmon spawning stream, and is used very sparingly as a feeding stop near the mouth by juvenile chinook during their migration downriver.

There is also very little evidence of use by other species of fish, including Arctic grayling, the application maintains.

No date has yet been set for a public hearing into the Minto Mine's application to the water board.

Meanwhile, the deadline to provide the YESAB with comments on the application from Western Copper for its Carmacks Copper project is Monday.

The proposal by Western Copper to use a sulphuric acid solution to retrieve the copper through a heap leaching process has drawn harsh criticism. It's been argued the technology is unproven, and that the Yukon River watershed is not the place to test it.

The YESAB, on the other hand, issued its overall project approval in July 2008, and is now considering the more specific application for a water licence.

The water board has scheduled Feb. 15 to 19 for a public hearing into the application it has received from Western Copper.