The King County Council on Monday overwhelmingly approved $19.1 million to help purchase 250 acres of rugged shoreline and forest on Maury Island, all but assuring the historic effort to secure the controversial mine site will come to fruition.

After scant debate, the council voted eight to one to approve the county’s purchase-and-sale agreement with CalPortland, corporate owners of the Glacier Northwest site on Maury. Only Councilmember Kathy Lambert opposed the measure.

In a subsequent vote, all nine approved the funding package, agreeing with County Executive Dow Constantine’s request to use $19.1 million from the Conservation Future Funds to meet the county’s share in the $36 million purchase agreement.

The vote means the funds are now teed up for the sale, which has to be completed by the end of the year to meet CalPortland’s needs. The conservation community is still committed to raising $2 million to refund a portion of the county’s expenditures, but the organizations spearheading the campaign can complete their fundraising effort after the deal is signed.

“The money’s all there,” said an ecstatic Amy Carey, who heads Preserve Our Islands (POI), the grassroots organization formed to fight Glacier’s proposed expansion on Maury, and who was in the council chambers when the council voted. “It allows us to move forward without any question marks.”

“This is a big huge snowball rolling downhill,” added Tom Dean, head of the Vashon-Maury Island Land Trust, who was also in the council chambers.

County Councilmember Joe McDermott, sworn in only a week ago to represent the 8th District, which includes Vashon and Maury Island, introduced the measure. After the vote, he said he, too, was elated by the outcome. The council’s near-unanimous support indicates the significance of the effort, he noted — the protection of nearly a mile of cobble shoreline in a county where 70 percent of its shorelines are developed.

“We’ve documented the ecological impact of this piece of land,” he said.

McDermott credited the successful vote to a decade-long effort on POI’s part to educate the region about the significance of the Maury mine site. More recently, he added, Kathy Fletcher, who heads People For Puget Sound, has helped considerably, helping to elevate the issue to one of regional importance.

“She really lent some credibility to the effort,” McDermott said.

Meanwhile, both Dean and Carey said the fundraising effort is going well. The two organizations have raised nearly $250,000, with gifts coming from as far away as Singapore, Carey said. POI and the land trust hope to raise $500,000 — a quarter of the amount needed from private individuals.

“Everyone’s pretty confident we’ll get there sooner rather than later,” she said.

The county plans to make the site — 250 acres of madrone forest and shoreline not far from the 320-acre Maury Island Regional Marine Park — a public park.

At Monday’s meeting, Lambert, a Redmond Republican, said she was concerned about the impact the county’s move could have on the region, which has considerable need for sand and gravel and currently imports much of it from Canada. Trucking sand and gravel into the region not only increases the costs of aggregates but takes a toll on the region’s roads, she said.

“I think it’s wonderful that we are in preserving this shoreline, but I was in favor of a compromise” that would have allowed for some sand and gravel extraction, she added.

But Larry Phillips, another councilmember, said he considers the pending transaction an appropriate end “to a long dispute” — doing so, he added, “in a reasonable and rational manner.”

He added, though, that the county work quickly to make the park accessible to residents throughout the county. “It’s not easy to get there,” he noted.

In a separate move, councilmember Jane Hague put forward a motion requiring county staff to determine by next June how it will cover the costs of remediating contamination on the site — pollution caused by Asarco’s arsenic-laden plume during its days as a copper smelter. Other costs, she noted, include removing the old mining structures that still exist on the site.

The motion passed unanimously.

Dean, with the land trust, said he believes the county council — often divided along party lines — agreed to cover the costs of the transaction in large part because both the conservation community and CalPortland strongly back the move.

“Glacier wants this deal,” he said. “This is not a pretend win-win. This is a real win-win.”