Massive sulfide zinc mineralization was first recognized in the Balmat-Edwards district in 1838 and first production began in 1915. Since then, the district has produced in excess of 43 million tons of ore from the Balmat, Edwards, Hyatt, and Pierrepont mine complexes with average grades ranging from 8.6% Zn to 16.4% Zn. The Balmat Mine operated continuously from 1930 – 2003, when production ceased due to depressed zinc metal prices. Production resumed in 2006 to directly address a projected, short term concentrate shortfall at the parent company’s smelter. The mine was closed and placed on care and maintenance in the fall of 2008 after the projected smelter need was addressed, in the face of a general economic turndown and resulting fall in zinc prices. The Balmat mine has produced a total of 30.7 million tons grading 8.6% zinc. The mine is fully permitted and in compliance with all current Federal and State mining regulations and is currently on care and maintenance status.
Geology and Mineralization
The Balmat-Edwards district zinc deposits occur in intensely folded, distorted and deformed Proterozoic metasedimentary rocks of the NW Adirondack Lowlands, subjected to high temperature and high pressure metamorphism during the Grenville Orogeny approximately 1.1 billion years ago. The zinc deposits are hosted in the Upper Marble Formation, a sequence of shallow water carbonate units characterized by siliceous, dolomitic, diopside-rich and evaporate-bearing marbles. Zinc orebodies exhibit tabular or pod-like geometries and occupy zones within the hinges and axial regions of folds and faults associated with the Sylvia Lake syncline, a major regional scale structure recognized at Balmat.
The Balmat deposits are classified as SedEx-type, commonly defined as deposits formed from precipitation of metals from brines generated by evaporation and movement of fluids through carbonate and evaporate-rich rocks in marine sedimentary basins. The fluids/brines leach metals as they migrate through the sedimentary pile along regional and local structures and ultimately reach the sea floor where the metals precipitate as lenses and sheets in favorable structural and stratigraphic settings.
Location: St. Lawrence County, New York, in the historic Balmat-Edwards Mining District
Ownership: Wholly owned by Star Mountain Resources
Permits: Fully permitted and in compliance with all current Federal and State mining regulations
Historical Production: 30.7 M tons grading 8.6% zinc
Mine Plan: 8.5-year with excellent potential to increase life of mine and mining rate
Mining Method: Modern mechanized underground mining using a combination of room and pillar and long hole stoping
Mine: 4000 tons per day hoisting capacity, rubber tired, mobile mining fleet
Mill: 5000 tons per day zinc concentrator, a tailings facility, a concentrate storage area, and rail and truck transportation infrastructure