Northeastern Section - 54th Annual Meeting - 2019

Paper No. 3-3
Presentation Time: 9:00 AM


SIMMONS, William B., MP2 Research Group, Maine Mineral and Gem Museum, 99 Main Street, Bethel, ME 04217, FALSTER, Alexander U., MP2 Research Group, Maine Mineral and Gem Museum, 99 Main St, Bethel, ME 04217, NIZAMOFF, James, 64 Mineral Drive, Hebron, ME 04328 and FREEMAN, Gary, 48 Lovejoy Road, South Paris, ME 04281

Recent excavation of a large spodumene bearing pegmatite on the north side of Plumbago Mountain has revealed a new, very spodumene-rich and potentially significant Li resource in Maine. The currently exposed portion of the pegmatite is principally composed of quartz, albite, muscovite and spodumene. Initial sampling indicates that microcline is sparse and occurs in the spodumene zone and in rare miarolitic cavities. Montebrasite, beryl, cassiterite, almandine-spessartine series garnets, fluorapatite and columbite group species are also present. To date, schorl, lepidolite and pollucite are extremely rare. The columbite group minerals include ferrocolumbite, manganocolumbite and ferrotapiolite. Triphylite pods up to 50 cm across occur throughout the spodumene-rich zone. Numerous secondary phosphates related to metasomatic alteration of triphylite and montebrasite have been identified including: ferrisicklerite, heterosite, vivianite, strunzite, childrenite-eosphorite series, whitmoreite, beraunite, bermanite, laueite, stewartite, messelite-fairfieldite series, rockbridgeite, phosphosiderite, jahnsite group, paravauxite, mitridatite, diadochite, hydroxylherderite and moraesite. Siderite-rhodochrosite occur replacing massive triphylite. The spodumene crystals are very large to gigantic, with one crystal exceeding 11 meters in length. Montebrasite also occurs in very large single crystal masses. Some exceed 1.5 meters across. The spodumene and montebrasite crystals rank among the world’s largest in size. The surface exposure is approximately 300 x 600 m and percussion drilling indicates that the spodumene bearing zone exceeds 20 meters in thickness, indicating a potential reserve of 3.6 million metric tons of ore. At 30% spodumene this is about 3 million metric tons of spodumene. Measured bulk lithium content based on 18 tons of mine run, is 4.6 % Li2O. The Fe2O3 content of spodumene is about 0.3 wt.%. Three million metric tons of this grade spodumene ore at current prices represents a Li resource with a value in excess of 3 billion dollars.