Results from field investigations conducted late in the summer of 2011 pointed to economic grade concentrations in at least three drainage basins, Ucore said, including the upper Kilolitna River, the Ray River, and No Name Creek.
Each basin displayed numerous surface gravel and sand samples containing at least 0.15 kilogram per cubic metre (kg/m3) of REE and/or tin, along with by-products like tungsten, zirconium, niobium, and tantalum.
Local samples contain up to 1 kg/m3 each of tin and REEs in the Ray River floodplain, and up to 9 kg/m3 tin in the No Name Creek and Caribou Heights prospect.
The sampling program also returned heavy mineral concentrates, including up to 50 percent tin, up to 10 percent total REE (TREE), and between 0.01 and one percent tungsten, dysprosium, erbium, and yttrium. These heavy REEs compose between 15 and 25 percent of the TREE in most samples, with the exception of the No Name Creek area, which delivered up to 60 percent heavy minerals in TREE samples.
"With the cooperation of the State of Alaska, Ucore continues to expand and advance its rare earth holdings in the most prospective areas of the state," said president and CEO, Jim McKenzie.
"The intent is to establish Alaska as the leader in American heavy REE exploration, extraction and development.
"The Ray Mountains project has select areas rivaling HREE content at our Bokan property, and the remarkable advantage of collateral tin, niobium and tantalum mineralization which enhances prospective values per ton.
"Ucore will be advancing the Ray Mountains area as a priority exploration target as it transitions its Bokan flagship into mine development."
On the TSX-Venture Exchange, Ucore shares hiked 13.92 percent to $0.45, as of 3:04 pm EDT.