Saturday, March 21, 2009

The Mountain View Lead Mine in Frederick County MD.

The above photographs show microscopic occurrences of anglesite (left) and smithsonite (right) from rocks that were collected at the Mountain View Lead Mine years ago.

The opening is located several miles southwest of Union Bridge in Frederick County. Worked during the 1890's, it marks the only fully documented site in Maryland ever mined for lead. The Natural History Society of Maryland’s 1940 publication Minerals of Maryland, by Charles W. Ostrander and Walter E. Price, Jr., names the "minerals to be found" at this locality as follows:

Galena, white cleavage barite, chalcopyrite in masses and octahedral crystals, bornite, green transparent and gray opaque sphalerite, specular hematite, calcite crystals, orange colored calcite cleavages, pyrite, epidote, chalcanthite, quartz crystals, and traces of malachite and azurite. Also cerussite and sulphur (Williams)

After an earlier excursion to obtain special permission for the visit, my son Dylan and I maneuvered our way through some quite thorny terrain to the Mountain View Lead Mine openings on the chilly overcast afternoon of March 13, 2009. The surrounding area was deeply buried in leaves, which obscured any traces of dumps that could remain. What appeared at first to be tailings consisted instead of slate/shale eroded from an embankment.

We searched for minerals by penetrating the cooperative soil near the openings with the chisels on the back of our hammers, then looking carefully through mud covered rocks beneath for any that seemed inordinately heavy or whose surfaces had a rounded and/or weathered look. Such rocks, though scarce, when broken open, bore generous amounts of galena. They were the same kind of rocks that yielded the anglesite and smithsonite micromounts pictured above

Though we failed to locate any anglesite or smithsonite, we did note in these galena bearing rocks small amounts of chalcopyrite, bornite, sphalerite, hematite, malachite, and azurite, and micro quartz crystals. In other rocks, we observed some of the white cleavage barite, orange colored calcite cleavages, and epidote as mentioned in Minerals of Maryland. The only minerals named by Ostrander and Price of which we did not find evidence were chalcanthite, along with the cerussite and sulphur they stated had been reported by Williams.

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