Five environmental groups filed court documents Tuesday in yet another attempt to force the Golden Sunlight Mine near Whitehall to refill its massive open pit once the company ceases gold mine operations.

But the state says that plan is more harmful to the environment than what it has proposed.

Members of the Montana Environmental Information Center, the National Wildlife Federation, the Mineral Policy Center, the Gallatin Wildlife Association and the Sierra Club are asking Helena District Court Judge Thomas Honzel to order the state to implement the judge’s 2002 decision by developing a partial backfill plan within 90 days.

If that’s not done, the groups want Honzel to suspend Golden Sunlight’s operating permit.

They’re also seeking an increase in the mine’s bond from about $55 million to at least $93 million, which the groups say would be the cost to Montana’s taxpayers if Golden Sunlight were to walk away from its obligations now.

In addition, they’re asking the court to hold Richard Opper, director of the Montana Department of Environmental Quality, in contempt of court for not moving forward with the judge’s previous order.

The case originally was filed in 1992. In 2001, Honzel ruled that backfilling was required, and ordered DEQ in 2002 to “immediately implement” the backfill alternative. Instead, the state said it took another scientific look at the issue and came up with this newest plan, released earlier this year.

“I don’t consider myself in contempt with the court,” Opper said on Tuesday. “But we will let the courts settle this one and make the determination.

“But I’m a little surprised MEIC took this position as hard as they are because it’s less protective of water quality than the reclamation plan we chose.”

At issue is whether the mine should replace the 47 million tons of waste rocks it removed from the 2,000-foot-deep, three-quarter-mile-long pit dug since the Golden Sunlight mine was permitted in 1975.

Jim Jensen, executive director of MEIC, said Montana’s constitution requires that all lands disturbed by the taking of natural resources be reclaimed.

“We’re not asking the mine be reclaimed to look like there wasn’t ever any mine there — that’s simply impossible,” Jensen said. “But they should do everything physically possible to reclaim this site … to provide for some future use.

“There’s 54 million reasons they selected the option they did, and the difference is cost — $55 million to backfill instead of $1 million to do the underground sump (pump) alternative.”

But Opper said that after considering all of the reclamation options, he decided that not putting the waste rocks back, but pumping water from the pit and treating it — necessary no matter what does or does not go in the pit — is the most environmentally protective plan.

His decision, outlined in a document earlier this year, was made in part due to the “incredible reactive” pyrite, also known as fool’s gold, that came out of the pit. Opper said that when the pyrite is exposed to water and air, it turns into sulfuric acid, which is a key component in acid mine drainage — the brightly colored, toxic streams of water that flow from some mines.

At this point, most of the waste rock piles are covered with soil and vegetation, which Opper said keeps water from reacting with the rocks to cause the acid mine drainage. He doesn’t want to disturb them again by putting them back in the pit.

Adding to the issue is that the rocks would cover the groundwater that has to be pumped from the pit. That water was already treated, and will need to be in perpetuity, to keep the acidic water from draining into the nearby Jefferson River.

Opper said he’d rather do that in a pit without backfill than to try to put drains underneath the waste rock that the environmental groups wants back in the pit.

“It’s a question of aesthetics versus water quality, and that’s an easy choice for me. They’re not great options we were faced with, but those are the two options,” Opper said. “I don’t like the idea of leaving a scar on the planet — it’s not a good legacy for the mine and I’m sure they’re not proud either — but backfilling is the wrong thing to do from an environmental perspective.

“I agonized over this until I was convinced through the (Environmental Impact Statement) process.”

At this point, the mine is slated for closure in the third quarter of 2008, said Tim Dimock, the mine’s general manager, although high gold prices are prompting consideration of whether to expand the mine. He hadn’t seen the lawsuit so declined to comment on it.

Warren McCullough, DEQ environmental management bureau chief, said the mine is going after some high-grade underground ore, and discussions are taking place as to whether to implement some previously approved expansions within the pit.

“That would extend the life of the mine,” McCullough said. “They haven’t made any formal application, but we have been discussing it. It probably wouldn’t affect the footprint of the mine,” which covers around 3,000 acres.

Reporter Eve Byron: 447-4076 or eve.byron@helenair.com