Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/210

182 F³. from the western outcrop for about 250 yards, crossing a small knuckle there and then dipping eastward, of course at a very gentle angle, for about 1800 yards, where it rises sharply again for the last 50 yards to its eastern outcrop. The structure of the basin, therefore, is by no means symmetrical, the axial line showing two rolls and passing much closer to the north outcrop than to the south.

The Shauberville opening (Messrs. Bucher, Rook & Swengle) is the first drift at the west end of the basin and all the ore mined from this point has been hitherto sent to the Union Furnace at Winfield. The gangway was driven eastward and keeping everywhere on the Sand Vein ore-bed it developed the structure already described for about 550 yards from the western outcrop. The vein shows entirely soft ore here about 28″ thick, with a small band of Jack showing in portions of the mine near the middle of the bed and varying from 0″ to 8″ in thickness. All the ore mined is conveyed by a tramway 2 miles long to the ore shutes at Adamsburg. Three samples of this ore sent in car lots for trial to the Logan Furnace in Mifflin county, yielded from 33½ to 40 per cent. of metallic iron and from 24 to 35 per cent. of silica; but with proper care in mining there is no reason why this ore should not furnish at least 45 per cent., though this is not possible if the Jack is included in the shipments.

The north rim of the basin from this opening to Dr. Smith’s mine shows everywhere a vertical dip, in places overturned at the outcrop and folded back so as to show a north dip parallel, or nearly so, with that of the same vein outcropping in the main ore ridge. A small fault may have developed between the two opposing outcrops on either side of the Ore ridge, which is made further probable by the fact that all along the north side of the basin, there is an overlap of the ore-bed, which, as far as developed, thins out on its outcrop to about 18″. Moreover the same brush takes place on the north dip, the hade of the fault dipping about 40°N. W. The vertical portion of the middle outcrop is largely twisted, and in the lower workings of Dr. Smith’s mine the rooms have developed perfectly