small pyrrhotite cement mill in Pittsburgh USA North America
pyrrhotitequartz crusherin Pittsburgh USA North America,Keystone Trap Rock Quarry Cornog Wallace Township Chester Co PennsylvaniaUSAA crushed stone quarry in Precambrian Grenville amphibolite gneiss within the Honeybrook uplift The mineral assemblages for which this locality is well known are the product of alpine cleft type
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