The Dahlonega Test Site: Test Bed For Evaluation Of Shallow Subsurface Geophysical Exploration Techniques

The Dahlonega test site is located in the eastern foothills of the Appalachians in<br>Georgia. Dahlonega, Georgia marks the southern end of the Appalachian trail at the<br>base of the Blue Ridge in northern Georgia. Founded as a gold mining town in the early<br>1800’s, Dahlonega is now primarily a historical attraction setting in the foothills among<br>abandoned gold mines and works. A facility for testing shallow subsurface geophysical<br>exploration techniques is under construction near the Chestatee River approximately 4<br>miles to the east-southeast of the town of Dahlonega. The test facility is labeled the<br>Dahlonega Test Site (DTS).<br>Geological characteristics in the immediate vicinity of the DTS favor a highly<br>weathered clayey mica schist with abundant quartz veins. The quartz veins are fairly<br>substantial, in some areas up to 3-4” in thickness. The veined schist formation is<br>overburdened by a clayey reddish soil. From the drilling operation there is observable<br>evidence of layering. At approximately 20 feet the medium changes from a reddish<br>material to the darker schistose material. The water table appears at approximately 50<br>feet. Data recorded from borehole deviation measurements made with an Owl tool<br>indicate that the boreholes are straight until reaching a depth of approximately 75-80<br>feet where they began to deviate. This deviation suggests the presence of more<br>competent rock appearing at this depth.<br>An air filled tunnel with an axis that is nearly perpendicular to the test site is<br>present at a depth of approximately 42 feet.