. Economic Papers. uality of thesesheets was very good. Buncombe County. New Balsam Gap Mine.—The New Balsam Gap mine is near the head ofNorth Fork of Swannanoa River, about 1 mile southeast of Balsam mine is on the face of a cliff about 70 feet high and a few feet to oneside of a waterfall over the cliff. It was worked by an open cut at thefoot of the cliff, about 60 feet long, extending into the cliff. A tunnel orstope 15 or 20 feet high was then driven back under the cliff on the vein adistance of 70 feet. The full width of the pegmatite, 6 to 8 feet, was re-moved in the tunnel, and
. Economic Papers. uality of thesesheets was very good. Buncombe County. New Balsam Gap Mine.—The New Balsam Gap mine is near the head ofNorth Fork of Swannanoa River, about 1 mile southeast of Balsam mine is on the face of a cliff about 70 feet high and a few feet to oneside of a waterfall over the cliff. It was worked by an open cut at thefoot of the cliff, about 60 feet long, extending into the cliff. A tunnel orstope 15 or 20 feet high was then driven back under the cliff on the vein adistance of 70 feet. The full width of the pegmatite, 6 to 8 feet, was re-moved in the tunnel, and the waste was left to accumulate in the bottomas a floor for stoping out the vein above. The country rock is much-folded biotite mica gneiss striking north and south, with a high irregulardip to the west. The pegmatite cuts across the schistosity of the countryrock with a strike of N. 45° E. and a nearly vertical dip. The pegmatite isvery irregular in size and in one portion exposed in the roof of the tunnel it. Figure 15—New Balsam Gap mine, Buncombe County, N. C. (a) Sectionshowing pegmatite pinched down to 10 inches and elbowing out abruptly;(b) irregularity of pegmatite expos3d in end of tunnel; lenticular-shaped crosssection with small side stringer and horse of mica gneiss. pinches down to about 1 foot in width but abruptly elbows out again toseveral feet, as shown in figure 15 (a). The irregularity of the pegmatiteis further shown by the exposure in the end of the tunnel, of which figure 15(&) is a vertical cross section. The pegmatite pinches down in the upperpart, is large in the middle, and smaller again at the bottom. On the westside there is an elbow in the vein with a small arm of pegmatite branchingoff into the mica gneiss. An irregular-shaped horse of gneiss was included inthe vein. The pegmatite is composed of the usual minerals segregated outinto coarse masses in places. The quartz and feldspar occur in masses 2 or 3feet thick, and the mica is richer in s
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