Palace Geothermal
We had a contract to drill and install 63 geothermal loops to 300' deep on a job that was black shale covered by a few feet of clay.
We drill with a Compact Sonic Rig however, the Sonic did not work well on the shale. Our bits would get plugged or packed in with shale. We tried a drag bit and it was painfully slow.
After spending 4 days to drill 3 holes, we contacted Kevin at Palmer Bit and he sent us a modified PDC to try out.
We drilled all the remaining 60 holes using the same PDC bit. 60 x 300' = 18,000 feet.
We could drill 2 and loop to holes a day. The bit looks like it could go another 18,000 feet.