Constantine Metal Resources has reported positive results from a preliminary economic assessment (PEA) of the Palmer zinc-copper-gold-silver project in southeast Alaska. The project is owned by the Constantine Mining LLC joint venture, with Constantine Metal Resources holding a 51% interest and Dowa Metals & Mining holding the remaining 49%. Constantine Metal Resources is the operator.

The Palmer PEA describes a low-capex, low-operating-cost, high-margin underground mining operation with attractive environmental attributes. Concurrent mining is planned for both the Palmer and AG Zone deposits. Site topography enables lateral underground access to the base of the deposits and bottom-up, gravity-assisted mining.

Mine design utilizes longhole mining methods, subvertical ore passes, and an underground crusher and conveyor to deliver mineralized material to the mill. Three high-quality concentrates (zinc, copper and barite) will be produced. A pyrite concentrate will also be produced for placement underground as backfill.

Based on current resources, mine life is estimated at 11 years after 24 months of preproduction development. Steady-state mining and processing rates are planned at 3,500 metric tons per day (mt/d). Preproduction development capital is estimated at $278 million. Mine operating costs are estimated at $65.4/mt.