Mine rebuilds trust a pile at a time

MAGNA — Kennecott Utah Copper's Paula Doughty this past week described driving across a field of old mining waste on the north side of Magna as like taking a trip across Kansas.

"It's kind of boring," Doughty said during a recent tour. "There's not a whole heck of a lot here."

Yes and no.

A century of digging at Kennecott's Bingham Canyon Mine has resulted in a hole that is two and a half miles across at the top and three-quarters of a mile deep. You can see the hole from space.

Dig a hole, create a monolithic pile — or two.

Two public tours of those piles April 23 and one April 26 will give 27 people — those who have signed up so far — an up-close look at what is essentially the byproduct of moving a mountain 15 miles away in the name of mining over the course of 100 years.

"We want to be open about our operations," Kennecott spokesman Kyle Bennett said.

They'll come looking for answers about seismic stability, risks and public safety related to one pile. Many, some skeptical of Kennecott's word, will want to know more about what they can't see on top of the piles.

They'll see drainage pipes and pipes used to monitor water depth below the surface of the old south impoundment. There will be a view of all the water on the newer pile, overlooking the Great Salt Lake. They'll learn more about the numbers behind Kennecott's tailings operations.

Like how Kennecott's newer north impoundment is 3,200 surface acres, with less than one-quarter covered by water that at its deepest is 25 feet or so. Along I-80 the earthen dam holding all that water back is about 80 feet high, with about 65 tons per hour of water and tailings being poured on top.

The north impoundment has been growing since it was activated about eight years ago, with the more coarse tailings used to build a dam around both the standing water and accumulating finer tailings particles that look like gray sand. The impoundment will be about 250 feet high by 2022, about 14 years before the viability of the Bingham mine is expected to run out.

"A lot of alternatives will be evaluated," Doughty said about where to put tailings after 2022.

The 5,700 surface acres of south impoundment, reaching heights of 250 feet, no longer hold water from waste operations. Except for a small pond that forms during heavy rain at a low point on the old impoundment, it's dry.