HELENA -- Voters resoundingly rejected an effort to repeal the state's ban on open pit cyanide leach mining, election results show.

Some 59 percent of Montanans voted against Initiative 147 compared with just 41 percent voting in favor, elections results showed at press time Tuesday. The Associated Press officially declared I-147's defeat shortly before 10 p.m.

"I'm happy and I hope all Montanans are happy," said Bruce Farling, executive director of Montana Trout Unlimited, which campaigned heavily against I-147. "I'm happy they rejected a $3 million campaign and we can move forward with responsible mining and clean water and put this one behind us."

I-147 would have reversed the state's ban on open pit cyanide leach mining and mandated certain environmental safeguards often required before the cyanide ban passed but not specifically spelled out in law. Additionally, the initiative would have restored to companies mineral leases lost or diminished by the ban.

Open pit cyanide leach mining is a process that extracts small amounts of gold diffused through large amounts of rock. Ore is mined in open pits and treated with a cyanide solution. Gold dissolves in the cyanide, which is captured and processed to extract precious metals.

Almost all the money behind I-147 came from one out-of-state mining company, Canyon Resources Corp., which wanted to build a large open pit cyanide heap leach mine near Lincoln when voters passed the ban. Canyon's mineral leases for the project have since expired, although the company has challenged that in court and continues to pay money for the leases.

The company gave just under $3 million -- or about 98 percent of the total -- funds behind the initiative, campaign finance records show. Their opponents raised just over $450,000 to defeat the measure.

Critics attacked Canyon's involvement, pointing out that the company had lost money every year for the last decade and alleging they were dragging its feet on cleaning up its only other open pit cyanide leach mine near Lewistown. That mine, the CR Kendall mine, closed in 1997 and has not yet been reclaimed.

Tammy Johnson, head of Miners, Merchants and Montanans for Jobs and Economic Opportunity, said it would have been easier to convince Montanans to vote for I-147 had Canyon not been so intimately involved.

"I don't fault Canyon for funding the effort. We're grateful," she said, adding that, ironically, without Canyon's money, the group probably wouldn't have had the money to launch I-147, at all.

Johnson said the vote signaled the end of gold mining and exploration in Montana. She said there probably wouldn't be any efforts in the future to repeal the ban.

"This closes the door on an era," she said.

Jeff Barber, of Montanans for Common Sense Mining Laws, said the lopsided vote showed that Montana voters can't be bought.

"This is an emphatic statement that the people of Montana can't be bought by an out of state corporation," Barber said.

Voters were much more resounding in their rejection of I-147 than they were in passing the original 1998 ban. That effort, called Initiative 137, passed by a thin 52 to 48 percent margin.

I-147 has already been challenged in court. A Lincoln-area landowner and the Montana Environmental Information Center filed suit this summer to keep the initiative off the ballot arguing it was unconstitutional in a number of ways. That case is now pending before Helena District Judge Jeffrey Sherlock.