Article published Jul 8, 2007

State looks at treatments in $1.8 million effort to stop acid flow into Belt Creek

By KARL PUCKETT

Tribune Staff Writer

State mining regulators plan to reopen the historic Anaconda-Castner mine near Belt next month to look for water leaks, marking the beginning of a renewed effort to stop one of the most persistent cases of harmful acid drainage in Montana.

The sprawling abandoned mine 300 feet below the surface, once a prolific producer of coal, is now a prolific producer of water loaded with acid and heavy metals. The toxic soup flows directly into Belt Creek.

"It's actually coating the bottom," said Ted Duaime, a hydro geologist with the Montana Bureau of Mines and Geology.

Part of the estimated $1.8 million solution might be as simple as planting alfalfa on top of the old mine to soak up water, according to mining experts.

Farmers have known for decades that seeding the deep-rooted crop can fix saline-soaked agricultural fields, but using it to reclaim a leaking old coal mine would be a first in Montana.

"It's something that's been used in a different application," said Bill Botsford, a reclamation specialist with the state Department of Environmental Quality's Abandoned Mines Section. "But it's been very successful in that application."

At its height, the Anaconda-Castner mine employed 1,000 men. A March 20, 1909, story in "The Engineering and Mining Journal" states it could produce as much as 3,500 tons of coal in 10 hours.

Today, it stands out for its stunning production of acid mine drainage, which has chased off trout and the food on which they live.

"Aquatic life doesn't like changes to their systems, especially something suddenly," Duaime said.

The 2007 Legislature approved $270,000 specifically for the reclamation of the Anaconda-Castner mine and the associated waste.

At this point, the total cleanup cost is estimated to be $1.8 million, with the rest of the funding coming from the federal Office of Surface Mining.

OSM taxes coal on a per-ton basis in 19 states and awards grants to clean up historic abandoned mines that operated before environmental regulations were passed.

Botsford says the acid mine drainage at the Belt mine has few rivals in Montana, if any.

"Certainly, this is the worst case and we're trying to get our arms around it," he said.

The main mine entrance, which is no longer open, is located just off the road that dips down into Belt, and the horizontal mine lies 300 feet below the grade of U.S. Highway 87.

A portion of the mine lies below the highway.

It discharges between 125 to 150 gallons of polluted water a minute, with some seasonal variation.

"And it runs straight through town," Duaime adds, referring to Belt Creek, which absorbs the runoff.

The discharged water has a pH of 3 — 0 is the most acidic and 7 is neutral. Duaime said that a piece of scrap iron tossed in the water would be visibly eaten away within a few days.

The mine also deposits 82,000 pounds of iron, 55,000 pounds of aluminum and 983,000 pounds of sulfate in the creek every year.

In Central Montana alone, more than 30 old coal mines are leaking heavy metals and acid water.

"You attack the worst sites first, if that's at all possible, and go from there," Bostford said.

Besides the acid mine drainage and heavy metals problems, 85,000 cubic yards of coal waste is buried in a flood plain near the mine and state officials are looking into moving it to a lined landfill. In the 1980s, a mountainous pile of "slag" caught fire and the state buried it. The entrances to the mine were closed at that time and nobody's been down there since.

The state is currently accepting bids from engineers to open the mine this summer.

The selected engineering firm will map where water is seeping into the mine through fractures so the state can then go to work curtailing the seepage.

DEQ hopes to have a contract awarded by July 17. Work on opening the mine could begin Aug. 1.

Authorities suspect most of the water in the mine is coming from snowmelt and rainwater that percolates downward.

Pyrite, commonly called fool's gold and found near coal seams, is causing much of the problem. Left alone, the pyrite, which contains sulfur, would cause no trouble. But when it's exposed to oxygen and water, it creates sulfuric acid and iron hydroxide, which drains out of mine entrances creating the acid drainage.

The problem periodically turns Belt Creek either a rusty color or milky white.

"That's a very bad impact to the environment as it's released from the mine," Botsford said.

It's a vicious cycle: As more acid is created, it erodes more pyrite.

Acid mine drainage is commonly addressed with either an "active" treatment, such as constructing a plant to clean the polluted water, or a "passive" system, which is installing wetlands or containment ponds to soak up the pollutants.

Neither is practical for the Belt mine, state regulators say.

An active system would have to be continually operated and maintained forever, making it cost prohibitive.

As for the passive approach, pollution concentrations in the Anaconda-Castner mine drainage gives it so much bite that it chewed up and spit out wetlands that were put in during the 1980s to catch the runoff.

"The vegetation couldn't recover and continue to grow in the spring," Duaime said.

Regulators are considering a third option called "source control" — in effect catching the water before it gets to the mine.

First of all, regulators say it's likely a 10-foot-wide, 7- to 8-foot-tall bulkhead filled with cement will be put up in one of the main tunnels in a flooded portion of the mine, which should cut down on water and oxygen flowing through the rest of the mine.

Horizontal pipes to drain fresh water above the mine workings also are planned.

The new idea in the source-control approach would be planting as many as 300 acres of alfalfa on top of the mine.

Alfalfa roots can sink as deep as 25 feet, much deeper than the roots of wheat. The idea is the thirsty crop will soak up some of the excess water that's getting into the mine.

"These varieties of alfalfa reach down to levels that even dry up some of the groundwater," Botsford said.

Farmers who own land above the Anaconda mine would be asked to consider planting alfalfa instead of wheat.

"For us to help them, they've got to help us," said Jim Larson, who owns land over the north end of the mine.

Reimbursement for any loss of profit as a result of the crop switch is being discussed, state officials said.

Larson currently plants wheat, which is more profitable, on his land, but says he's willing to consider planting alfalfa.

"Obviously, that needs to be cleaned up," he said.

For decades, dry land farmers have used alfalfa to solve saline seep, which occurs as a result of the crop farming system of rotating fields. Under the system, large portions of land are left open in alternating years. The purpose is to allow moisture to build. But in Central Montana, there's a shale zone 40 feet below the surface. Excessive moisture builds up on the shelf and drives salt in the soils closer to the surface, which kills plants.

Applying the alfalfa absorption technique to a coal mine reclamation would be a first in Montana, regulators said. But if it works, it might be applied to other areas with acid mine drainage problems, Botsford said.

The Anaconda-Castner mine hasn't operated since the 1920s and Duaime said he's curious to get a look inside.

"It will be an example of very old-time mining practices," he said.

The mine, which opened in the late 1880s, has a network of haul roads covering 2 1/2 square miles. In length, the mine is about as long as the distance from Warden Bridge in Great Falls to Van's IGA on 10th Avenue South.

A map of the haul roads looks like a city street map, with roads crossing each other vertically and horizontally.

Men guiding horses pulling wagons, and later 2.25-ton ore cars, used those roads to get the coal out. One load equaled 48 cars.

Frank Ballatore, a 68-year-old Belt resident whose father worked in other Belt-area coal mines, has been in the mine. As a kid, he and friends, flashlights in hand, used to go exploring in the Anaconda-Castner mine. He recalled the big pillars and haul roads that went back seemingly forever. "It's a huge mine," he said.

Ballatore said that he hopes the drainage can be stopped.

"It looks terrible during the summer," he added.

But mindful of the wetland ponds that didn't work, he's reserving judgment on the new source-control approach.

"There are a lot of people who would like to see the problem fixed," he said. "But I don't know ..."