The deluge of rain in the Carmacks area is forcing the Minto mine to release untreated water containing metals above its water licence limits.

The Yukon Territory Water Board has issued an emergency order allowing for the discharge.

Stephen Quin, president of Sherwood Copper, said some metal content in the water does meet the Yukon licence standards, but is very close, and is well within federal standards.

The heavy rainfall has simply swamped the treatment system and the mine's ability to treat the water before discharging it.

Its storage area is full to the brim now with 400,000 cubic metres.

It needs to be drawn down to almost empty to allow for another 150,000 cubic metres of water diverted to the phase one open pit, and any additional rain before the snow flies, he said.

Quin said the emergency order from the board permits Minto Explorations, Sherwood's wholly-owned subsidiary, to spill up to 200 litres per second.

The mine right now has two, 15-centimetre pipes siphoning out water from the storage area, and will add more until it hits the 200 litres per second, he said.

Quin expects it will require 10 to 15 days to remove 350,000 cubic metres of water.

While the water licence permits copper concentrates in discharged water of .01 milligrams per liter, water being spilled contains .05 mpl, or five times the licence level, Quin said.

He pointed out, however, federal standards allow for copper concentrations of .3 mgl to .6 mgl, or 30 to 60 times higher than what the mine is releasing.

The total number of suspended solids being released is still well under what the licence permits, Quin pointed out.

He explained the mine, which is just wrapping up its first year of production, would normally use its onsite water treatment system on a seasonal basis, such as during spring runoff to manage the level in the storage area.

The mine uses the storage area to collect water for use during arid times and through the winter months.

But there's been so much rain and runoff from the entire valley and not just the mine site, the storage area has filled up so fast that it's not possible to run the water through the treatment plant before discharging it, he said.

Quin noted a section of the mine haul road from the Yukon River at Minto Landing into the mine site has been washed out by the flooding Big Creek.

The Big Creek, he pointed out, rose two metres in 24 hours, triggering flooding over three to four kilometres of road in the direction of the mine from the bridge.

The mine lost the use of the road Monday. However, with water levels receding, repair crews armed with dump tracks and a backhoe will have the artery back in use some time tomorrow, he said.

There are currently 120 or so Minto mine employees on site.

There was never any issue with supplies, Quin pointed out, noting the mine does have a large airstrip if there ever was.

He also pointed out the temporary loss of the road has had no impact on its schedule to ship ore concentrates out of the port of Skagway, Alaska.

There are 12,000 tonnes sitting in Skagway, and a full shipment is 9,800 tonnes, he said.

Extreme rainfall has also played havoc with the North Klondike Highway just south of Carmacks, forcing a closure earlier this week, though it remains open today.

Precipitation in the Carmacks area is breaking rainfall records.