I am installing a short tower. The soil is very dry, mostly volcanic ash
and low conductivity. I had the backhoe operator drill several holes 4
feet deep for grounding. It is impossible to drive a ground rod deeper
than 4 feet due to bedrock. What should I use to fill the holes after
the ground rods are installed?

Do a web-search for "bentonite" and "ground", and you'll learn lots!

Although I've never used it (but I'm going to start!), "bentonite" is
the appropriate stuff to use. When wet, it expands inward to squeeze
the ground rod and outward to press firmly against the soil, thereby
resulting in (effectively) a very large-diameter ground well-connected
to the soil.

Clumping-type kitty-litter is supposedly bentonite (a clay material),
so it should be relatively cheap.
--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

On 22 Dec 2005 13:53:30 -0600, wrote:

I am installing a short tower. The soil is very dry, mostly volcanic ash
and low conductivity. I had the backhoe operator drill several holes 4
feet deep for grounding. It is impossible to drive a ground rod deeper
than 4 feet due to bedrock. What should I use to fill the holes after
the ground rods are installed?

Do a web-search for "bentonite" and "ground", and you'll learn lots!

Although I've never used it (but I'm going to start!), "bentonite" is
the appropriate stuff to use. When wet, it expands inward to squeeze
the ground rod and outward to press firmly against the soil, thereby
resulting in (effectively) a very large-diameter ground well-connected
to the soil.

Clumping-type kitty-litter is supposedly bentonite (a clay material),
so it should be relatively cheap.

Hi Myron, how are you these days? If I recall, bentonite is used in
the oil patch as a slurry to seal the drill hole. It is called
drilling mud in that context. It should be pretty cheap!

Russ

On Fri, 23 Dec 2005 03:24:56 GMT, Russ wrote:

Hi Myron, how are you these days? If I recall, bentonite is used in
the oil patch as a slurry to seal the drill hole. It is called
drilling mud in that context. It should be pretty cheap!

It is also used in sand foundries in their molding sand.

Danny, K6MHE




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