ANCHORAGE — The Alaska Mental Health Trust Authority is preparing for another season of exploration for heavy minerals on its land northwest of Yakutat. It has approved $3 million for the project.
Results from previous drilling at Icy Cape were promising enough for the Board of Trustees to spend more on exploratory drilling, the Alaska Journal of Commerce reported.
The Alaska Mental Health Trust is a state fund with resources designed to ensure that the state has a comprehensive mental health program. Beneficiaries include Alaskans with mental illness, developmental disabilities, alcohol and substance-related disorders and traumatic brain injuries. The authority administers the trust.
The mineral prospect stretches for more than 30 miles (48 kilometers) along the Gulf of Alaska at the entrance of Icy Bay and covers roughly 75 square miles (194 sq. kilometers).
Previous preliminary exploratory drilling did not cover the western portion of the property, said Wyn Menefee, trust land office director.
“We also need to do some more on the eastern side of the property,” he said. “There’s just more to do before you have a better picture of where everything’s located.”
Early drilling samples from the broad delta at the point of the cape indicate ore could be up to 40 percent heavy minerals. Overall, an average of 26 percent of the sands are heavy minerals, according to the Trust Land Office’s 2016 annual report.
The “ore” is mostly old beach sands and are roughly equal portions of epidote and garnet in areas of highest concentration. Small amounts of zircon and gold have been identified.
Epidote and zircon are semiprecious gemstones. Garnet has been used as a gemstone and more recently as an industrial abrasive.
There is a misconception that mining Icy Cape heavy minerals would mean digging up the beach, Menefee said. Much is forested and portions have been logged.
“It’s the course of time that creates these sandy forelands; so even though they are considered beach sands, it’s not the beach,” he said.
The sands include material eroded and washed down from steep mountain faces above and sediments that tidal and wave action have pushed up. Most exploratory drilling has been done from logging roads, Menefee said, to a depth of less than 100 feet (30 meters).
As a placer deposit, the mine would be “much more akin to gravel operations,” he said.
Menefee stressed it was “way too preliminary” to forecast a development or partnership structure.
“I think that likely we are going to have anything from a few to several more years (of exploration) and a lot depends on the results of our drilling, the distribution of what we find,” he said. “It’s hard to tell right at the moment how long that (drilling) program will last before we would move toward an actual mine.”
The Trust Land Office manages roughly 1,562 square miles (4,045 sq. kilometers) of Alaska land.