Orange Goo Eats I-90 Again Fix Is Several Years And Millions Of Dollars Away

Although it’s chock-full of minerals, the bubbly orange stuff that sinks a stretch of Interstate 90 near Kellogg each year definitely isn’t Tang.

It’s rusty ground water, likely leaching from the Bunker Hill Superfund site tailings pond south of the freeway. The water contains zinc and iron and has caused the freeway to buckle for years. It is tested weekly for toxicity, and it ends up in the South Fork of the Coeur d’Alene River.

The freeway west of milepost 49 is driveable now since the Idaho Transportation Department resurfaced I-90 from Pinehurst to Kellogg. The $927,000 job was completed earlier this year. But the dip is expected to come back - filling the yawn in the roadway has become an annual rite.

“It’s just an ongoing maintenance problem for the past six or seven years,” said Barbara Babic, a Transportation Department spokeswoman. “We have not found a solution to the ground water or whatever. … The new pavement won’t fix the problem.”

No one is really sure how the water gets from the tailings pond to the other side of the freeway, where it collects in shallow, murky pools.

“There may be a sandbar or something underneath, nothing like a culvert we could actually fix,” said Scott Peterson of the Division of Environmental Quality. “Short of tearing up the interstate and scooping out a lot of material, I don’t know what can be done.”

Highway engineers don’t want to get anywhere near the stuff.

“The reason we didn’t just excavate it and rebuild was we didn’t know what was under there,” materials engineer Jeff Drager said. Engineers worried the water beneath might be toxic. “We didn’t want to stir something up.”

Scott Brown of the Idaho Conservation League said he’s more concerned about cleaning up the entire Superfund site than he is about the bog forming beneath the freeway.

This muck just happens to be visible from the freeway, he said. “There’s a lot of places up there, there’s a lot of runoff that’s happening. … It’s been ignored, downplayed and given inadequate funding for far too long.”

There once was talk of purifying the water, or building a trench to keep it from leaching under the freeway and into the river. But the cost was too high, DEQ’s Peterson said.

“It was in the millions of dollars,” he said. The entire area - a 120-acre tailings pond and a 60-acre gypsum pond - eventually will be sealed in about $30 million worth of underground plastic.

“It’s a pretty big baggy,” Peterson said.

That will permanently prevent leaching, but the work is four or five years away. Meanwhile, Peterson said, the toxicity level of the water flowing under the freeway doesn’t justify spending another few million dollars.

“Really, we’d only be Band-Aiding the problem,” he said. DEQ tests show the water doesn’t affect the river very much, and the traces of metal are minor. Its orange color is caused by iron, he said, which by itself isn’t toxic.

“No one likes it. It tastes bad, but it’s really not that bad for you,” Peterson said. “It’s carrying metals, don’t get me wrong. But for us to fix it, right now … I think we could spend our money in better ways.”

, DataTimes ILLUSTRATION: Graphic: Leaking mine tailings pond