KETCHIKAN, Alaska - A company seeking to pull copper, gold, zinc and silver from Prince of Wales Island has pegged the year 2015 as its start date, though the company's CEO acknowledges the deadline is optimistic.

Heatherdale Resources, the Canadian company managing the exploration effort, has raised estimates of the site's resources from 4.4 million tons to 6.6 million tons, the Ketchikan Daily News reports.

The higher estimates come as Heatherdale pours $10 million into the site, called the Niblack Project, that will increase its share to 60 percent of the project by August. The company hopes to raise its stake to 70 percent by paying for U.S.-mandated regulatory studies.

Heatherdale CEO Patrick Smith told the newspaper workers could pull about 2,000 tons of ore per day from the site for 10 years. The site costs about $1.5 million per month to explore.

Smith says the company must conduct several feasibility studies before beginning to get permits to construct a mine. He acknowledged to the newspaper that a start date of 2015 is "a very aggressive, optimistic scenario."

The Niblack site has a history of mining and exploration going back to the early 1900s, when 20,000 tons to 30,000 tons of ore was mined there between 1902 and 1908 and sent to Washington state for processing. Exploration resumed in 1974.

In 2008, Heatherdale took a controlling stake in the project. Smith said the company has since been able to build on the geological work done by previous generations of miners.

"Each company progressed the property," Smith said. "And the benefit to us is we have all of that drill core to look at, we have all of the geology that was done, all of the maps, and we can build on that. And we have."

Heatherdale now has three drilling rigs at the site to continue the exploration work to further define the amount of resources there. Two of the drills are underground. A third, helicopter-portable rig began work above ground several weeks ago, Smith said.

The ore likely won't be milled at Prince of Wales Island - there's not enough hydroelectric power on the island, and generators using expensive diesel fuel appear to be the only substitute.

"We can ship that ore on a barge to other places in Southeast Alaska or (British Columbia) and look for a place that has better infrastructure, maybe cheaper power," Smith said.

Smith said Heatherdale will hire locally for the work. The year-round exploration work at the Niblack site involves about 35 people.