Posted By BrianPK on 17 Nov 2014 04:31 PM
How important is it for vertical geothermal bore holes to be grouted from bottom to top. My installer insisted that he had to only shovel the drilling tailings back into the boreholes. He said that the granite dust in the tailings provided the best thermal conductivity of anything. I have two boreholes 300' deep running an envision nd038 in the south.
But the voids between the cuttings have the worst conductivity, unless the hole is filled with water. Then the borehole would likely connect different aquifers, which makes cross contamination more likely. A closed loop vertical borehole should be treated like an abandoned well.
BS alert meter is swinging to the high end of the scale....