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This data layer contains the mine polygons found on the 1:24,000-scale bedrock-geology maps of Ohio. The mine polygons were drawn on the maps to show where surface mining has affected the depiction of the bedrock geology. Detailed mapping at 1:24,000 scale was performed in Ohio from the 1960's to the 1980's. During that time period, 37 7.5-minute quadrangles were mapped in detail. The bedrock-geology mapping program was initiated at the Ohio Division of Geological Survey in 1991 to perform reconnaissance geologic mapping at 1:24,000 scale. The reconnaissance and detailed geologic mapping have been combined together into this GIS dataset. There will be edge-matching issues between the reconnaissance and detailed geologic maps. |