Concerns about arsenic leaching into the Snoqualmie watershed have the U.S. Forest Service considering a $500,000 plan to clean up a former copper mine near North Bend.

The Rainy Mine and Mill operated in the 1950s in the foothills of the Cascades about 12 miles northeast of the city, digging up and milling 2,000 tons of copper and silver. Waste rock from site was placed at the portal of the mine, and a 2008 study found high levels of arsenic in that pile could threaten the environment.

“One concern is the actual exposure of people and wildlife to arsenic on the site,” said Rod Lentz, forest service project manager. “Another concern is the fact that we have surface water leaching through that material, picking up some metals.”

In 2002, the forest service began an inventory of mines in the western Cascades. Rainy eventually came to the top of the list as one of the sites likely to need a cleanup.

The agency is now taking public comment on a plan to clean up the site. Plans call for an upgraded road to the mine, and the digging up and moving of 2,200 cubic yards of contaminated earth and rock. The excavated earth would be placed in a soil-covered repository, protected by diversionary channels and landscaping.

The half-inch-thick plan can be read at the North Bend Library and the Snoqualmie Ranger District office in North Bend. It can also be viewed at www.fs.fed.us/r6/mbs/projects/cercla-hazmat-cleanup-projects/index.shtml.

Comments will be taken until Jan. 11, 2009. They can be mailed to Y. Robert Iwamoto, Forest Supervisor, Mt. Baker-Snoqualmie National Forest, 2930 Wetmore Ave. Suite 3A, Everett, Washington 98201, or e-mailed to Realty Specialist Miki Fujikawa at mfujikawa@fs.fed.us.