# Digging through cap rock



## SDG (Oct 3, 2008)

Looks like we are about to start a job to dig a two acre lake. Looking at the soils report, cap rock is about 10 feet down. Plans call for 15 ft depth.
Any dug through cap rock before, and using what?
I was going to put a JD 330 on the job, but I think I would need a machine with a shorter arm


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## Ironman (Oct 16, 2008)

Cap rock sucks thats for sure, but with the right machine you can be fairly productive ( as far as digging in rock is concerned ).

The last time I got into cap rock it was about three foot thick it was slow going but I had a JD450 digging it and it wasnt horrible but not fast by any means.

just take your time and try not to overwork the machines capacity and youll be ok. hope you gotta good rock bucket a GP wont hold up long.
If the rocks not all that thick you may be alright.
Good luck


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## denick (Feb 13, 2006)

Hi SDG,

Welcome to E&SW forum of Contractortalk.com.We don't have cap rock in CT. As far as I know. 

Stop in the CHAT ROOM at 9PM.


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## SDG (Oct 3, 2008)

*Cap Rock*

Ironman was right...started using the kobelco 350 couldn't handle it
Had to get the Hitachi 850...damn thing is expensive
Slow going.:sad:


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## rino1494 (Jan 31, 2006)

Please define cap rock.


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## JPF (Dec 20, 2006)

rino1494 said:


> Please define cap rock.


Basically, Caprock is fossilized coral substrate......pretty much like trying to scratch through granite. It's all over at different depths down here in S. Florida.......used to excavate swimming pools years back, and it can be a real nightmare. Some guy's actually carry a wrecking ball with them to pound the heck out of the rock before trying to excavate it. They use charges at the rock pits to blow it out before dragline........bad juju!!:no:


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## dayexco (Mar 4, 2006)

what's a rock?


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## JPF (Dec 20, 2006)

dayexco said:


> what's a rock?


My wife say's it's my head.....:blink:


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## Blas (Jan 29, 2008)

If its like granite I would just blast it and be done with it. We use a D8 with a big ripper for limestone but that sounds pretty hard core. The one thing I know about granite is that you are not going to rip granite around here, it gets blasted period.


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## Driftwood (Feb 15, 2004)

*Granite is a beautiful thing !!!!*

In a kitchen


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## rino1494 (Jan 31, 2006)

Blas said:


> If its like granite I would just blast it and be done with it. We use a D8 with a big ripper for limestone but that sounds pretty hard core. The one thing I know about granite is that you are not going to rip granite around here, it gets blasted period.




I agree, blasting or hammering is the way to go.


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## SDG (Oct 3, 2008)

*Cap Rock Unleashed*

Really slow going, but its fun!!!!
except when you blow the main jack
started with Hitachi 800, now using 850


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## SDG (Oct 3, 2008)

*Finished*

finally after three months:clap:


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## tgeb (Feb 9, 2006)

Looks nice, nothing quite like a 3 month project. 

Only thing is how do we know it 15' deep? Could be 2' it would look the same from here.


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## SDG (Oct 3, 2008)

*take my word for it*

Scouts honor!!

on the Hitachi's stick its 14 feet from bushing to bushing, with the bucket its another 4'
I found one picture with the boom extended.


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## tgeb (Feb 9, 2006)

OK! Looks deep alright, well in 2 spots any way. :shifty:

Just curios....what is this pond for, and what did you do with all the material? Haul it off site?

Nice clean work.


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## SDG (Oct 3, 2008)

2 reasons: Its actually a retention pond per the design, for a cemetery! and to use the material as backfill to bring up the elevation since the water table is so high here. It would be easier to sell the material and bring in better suitable material for the fill, but due to county regs, you would have to get a mining permit to do so (it could take another six months.)

we are waiting on decision to crush the rock to use for road final.


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## JCLadson (Jun 19, 2009)

I would really like to pursure something in excavation.


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## FthillGuy (Jun 22, 2009)

Nope, stay in school...:thumbsup:


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