Tomorrow is the last day to comment on a Superior National Forest proposal for more mining exploration at the edge of the Boundary Waters Canoe Area Wilderness. Learn more and speak up at www.preciouswaters.org.

Last June, I spent a day canoeing down the South Kawishiwi River with reporters and photographers from two major Minnesota news outlets. We launched at a Boundary Waters Canoe Area Wilderness entry point a short portage from the Spruce Road, then almost immediately left the BWCAW as we headed downstream toward Birch Lake.

Also in our party was my Friends of the Boundary Waters Wilderness colleague Betsy Daub and local Ely canoe outfitter and guide Jason Zabokrtsky of Ely Outfitting Company (and his dog Lexee, who I'm pretty sure has spent more days in a canoe than any other dog in the state).

It was a beautiful, but nondescript, few miles of river. A snowmobile bridge crossed at one point, as did a power line. While we saw a handful of parties camping, canoeing and fishing during our brief trip through the Wilderness proper, we saw no one on the river outside the BWCAW border. We did see mother mergansers nervously herding their tiny chicks around the shallows, dragonflies zipping over the water, and turtles sunning themselves on logs.

Our group was there to see the area targeted by mining companies seeking copper, nickel and other metals in sulfide ores at the edge of the Boundary Waters. Development of such mines in the area have not gotten as much attention as PolyMet, the first company to try to open up such a sulfide mine in Minnesota. PolyMet, further along in the process, is some 15 or 20 miles southwest of where we were paddling.

The river we were on is in the middle of the area of interest for companies including Twin Metals — a joint partnership between Duluth Metals, a junior mining company based in Vancouver, and a giant Chilean conglomerate called Antofagasta. The partnership also recently acquired Franconia Minerals, making for a real mining juggernaut.

On the way to our canoe put-in, we stopped at a clearing on the side of Highway 1, where a couple young men ran a noisy drill mounted on the back of a truck. Gray sludge from the drill was pumped into a holding pond excavated nearby. The iconic north woods highway just east of the South Kawishiwi River is lined by such clearings in the woods, a wooden sign with a number nailed to a tree by the road, and red pipes jutting out of the ground, capping old drill holes.

Already, Boundary Waters users are experiencing the noise of these drilling operations while on wilderness canoe trips. And Birch Lake, popular for fishing, camping, house boating, and all sorts of other classic Minnesota activities, is really feeling the brunt. Homeowners and resort guests hear around-the-clock drilling, and they fish the lake alongside drill barges.

On our canoe trip, we portaged around a last set of rapids and then stopped at the Outward Bound camp on the Kawishiwi, where they have been sending young people into the wilderness since 1964. A staff member talked to us about how he could often hear the drilling in his cabin at night.

And now, the Superior National Forest is considering a new plan for more mineral exploration in the area. The comment period closes tomorrow on the environmental impact statement for 33 permits to explore for which several companies have applied. This means more roads and ripped-up forest in this area, popular outside the wilderness for hunting, hiking, birding, and ATV and snowmobile riding. More importantly, it sets Minnesota down a path toward giant mines at the edge of the most popular wilderness area in America.

These aren't just any mines, either. No, these aren't the iron mines that "helped us win World War II," as some are fond of repeating. This is a new beast, with pollution problems that Minnesota has never previously encountered. Last June, after paddling the South Kawishiwi, we visited an old site along the Spruce Road where a company had dug up a bunch of rock in the 1970s, seeking copper and nickel. Nasty orange soup was leaching out of the rock pile and into a nearby wetland.

The Friends had the drainage tested in an independent lab, which showed levels of copper, arsenic and other metals and chemicals which exceeded water quality standards and could pose a threat to both aquatic life and human health. This was 36 years after the rock had been excavated, and of course the company that did the digging is long gone.

Certainly, we have heard much about the benefits these mines could provide. Jobs and metals needed for modern technology, primarily. But there is a wilderness cherished by tens of thousands where these metals happen to be buried. And outside that wilderness are thousands of acres of public land — wild lakes and rivers, vast forests. For the many that believe the clean water, healthy forests and wilderness of northern Minnesota is something special, putting it all at risk for a couple decades of mining seems like a poor trade-off.

The mining industry has not given us much reason for confidence, besides a lot of talk about "doing it right." In addition to the Spruce Road acid mine drainage, there was the PolyMet environmental review, which earned a failing grade from the U.S. Environmental Protection Agency in February 2010. The EPA doesn't make a habit of handing out such low rankings and in fact they've only given the grade they gave PolyMet to less than one percent of the 11,000 projects the agency has reviewed since 1987.

The environmental impact statement for the mineral exploration near the South Kawishiwi and Birch Lake is unfortunately flawed, too. It tries to do two things — provide high-level guidelines for even more exploration anticipated in the future, and review impacts of the 33 permits up for consideration — and doesn't do either very well. There is not nearly enough information about how noise pollution in the BWCAW will be prevented, what will be done to ensure local ponds and streams are not de-watered, or how species like the Canada lynx and wolves will be protected. You can learn more on the Friends' website.

We started and ended our day of canoeing last summer at River Point Resort, located where the South Kawishiwi enters Birch Lake. Husband and wife Steve and Jane Koschak run it, hosting vacationers in quiet cabins, and outfitting canoe parties heading out on wilderness canoe trips. Steve's dad started the resort as a fishing camp in 1944 and Steve built many of the resort's buildings himself. Those cabins were built to last.

Learn more about the mineral exploration proposal and comment by the end of the day tomorrow, June 30.