Postholes, rocky ground, and cleanout

[jpav]

So, I've not yet purchased something to dig a lot of post holes with. So, bringing out a guy to do it. He has a 'mini' ex, but it is twice the size at least of what you see sitting in the rental yards from bobcat etc. He said it is around 7000-8000 lbs with the auger mounted.

Anyhow, he came out the other day, and started on a half doze on the holes. Trying to go 8"+ and around 3' deep. Well, we've got a lot of rock, mostly baseball to softball size. So, hard for him to dig a hole, and not possible to clean it out while digging.

So, I sat there with gloves, and a shovel, trying to clear away stuff that got pulled to the surface, then he would try and little more, then stop, etc. That worked, but when done, there was just a 6" depression, with loose rocks in it.

He said he would have to leave and come back later, to try something different, and suggested I soak the areas to dig with water.

So, after he left, I cleared out a few of the holes with a manual clam type digger. About 5 min and they were down 2 feet. All the stuff was loose. Not all that bad. Tried watering one of the holes as well, and that was better. As he mentioned, then the sides of the hole would be soft and allow the rocks to push into it more.

So, he is heading back out this weekend. I've watered a good bit, in some holes I hand started for a few inches. He is going to bring out a bunch of different size bits to try as well.

So, long, long story short. Any ideas/suggestions on how to help with the cleanout of the holes. We'll have 3 of us now to operate the manual diggers or pulling out rocks by hand. Around 70 holes to do now.

Maybe I should take a picture of the process.

 

[Lloyd_E]

Sounds like a lot of grunt work.

I would use a larger auger or dig with the bucket and back fill.

Pictures would be helpful.

lloyd

 

[Sniggle]

Sounds absolutely ghastly...good luck and please provide some pictures and a report on your success.

 

[jpav]

Yeah, not fun stuff. I can't dig it easy with my backhoe, so the dig and fill option is out, and some of the areas don't allow for that much space.

I've taken a couple of picts of the holes alread dug/started in case I forget to have the cam with me while working on this on Saturday.

One local guy with a large backhoe and auger won't even touch the job he says. Guess he knows what it is like out at my place.

Guy coming out is going to bring a 6" and 12" auger as well as the 9" he tried with the other day. The 9" holes are about 10-18" at the top from the rocking around back and forth and some of the top stuff falling in.

If I remember to have the digicam out there while working on this, I'll get some video clips up here for all to see as well.

Sorta wondering if a rock bit would grind up the rock into little pieces or not. One of the local rental yards says they have them for only $25 a day. Not sure if it'll mount on his rig, but worth a try if things don't work out, and I'll suggest that to him.

Thanks all for feeling my pain (or the pain that is to come after this project).

 

[bcp]

Trying to go 8"+ and around 3' deep.

Around 70 holes to do now.

You didn't mention the purpose or style of the fence, but I would redesign the fence to use T-posts, or high tension wire with very wide post spacing.

Even in rocky ground you can usually get a T-post within a foot of the desired location. It may twist or lean but the lean is easily corrected and I ignore the twist.

Bruce

 

[jpav]

Yup, you're right, I didn't say what type of fence did I. Ooops.

Well, we're trying to match the style of fence near the houses on the rest fo the property. Wood posts, wood rail top and bottom, and non-climb horse fence wire on that. The rails are 2x6 (with another 2x4 and 2x6 on the top side to form an upside down U so you or the horses can lean on it, or put something on top or whatever) and posts 4x4. Existing fence like this has been there at least 30 years, and only a few of the posts have been replaced to pressure treated (we are going all pressure treated wood posts).

I think I know why the existing post are only 2' in the ground on average

You are more than welcome to try to come out and pound T posts on my property. I'll even pay ya to do it! It is not easy. I've considered buying a jackhammer to start holes to allow T posts to go in more than 6 inches. Most of them will barely go in far enough to get the spade portion to contact the ground. Currently have about 1.5 miles of T post supported fence around the property, and none of it is all that secure. Plus, kinda hard to attach a rail to a T post and make it look ok. The current style of fencing doesn't look all that bad for what it is, and stands up to the wind and horses (and goats and pigs) very well.

A lot of the fencing in this project is around the yard near the house fence, so want it to look good, and last for a long time. Personally don't think T post fencing looks as good as wood posts. And, want it to match what is there. This fence is to keep horses, pigs, and goats out, and dogs in.

Still looking for some sort of post pounder, or option to fix the T posts we have, but that is not the style of fence for this project.

I guess I'll get some pictures up here of all this, either in progress, or if not, at least when it is done.

Thanks for any other ideas on how to clean out the holes.

Josh

 

[bcp]

I wonder how one of the hydraulic post pounders would work with a sharpened 4x4.

http://www.shavermfg.com/Dr.html

http://www.tractorbynet.com/forums/john-deere-owning-operating/92488-fence-post-driver-question.html

Bruce

 

[HL649]

Try to find a vibratory post pounder. They work great in rocky soils. We used one to put posts in an old gravel pit where drilling and pounding didn't work.

 

[germanbodyman]

Hi Josh

Last week I had holes put in the ground were the new equipment shed goes. The area had about 80 -90 trees there before I cleared it. I pushed most of the trees over with the tractor (a bit scary at times), but a lot of the roots were left in the ground.
I had a guy coming in with a Hydravac truck Dig it! Hydrovac excavation, slot trenching and shoring solutions by Badger Daylighting to dig the holes. 18 holes at 7 feet deep, 14 inches around were done in 6 hours. He went through roots, gravel, some rocks clay etc. Not cheap at 50 bucks a hole, but no caving in or loose soil beside the hole.
When I put a base layer of 1/4 inch crush in the hole, I overfilled one of them. So I had to remove about 18 inches of it. How do you remove the crush out of a now 4 1/2 feet hole? I don't own a clam shell digger. Out came the big shop vac and everything was sucked out in less then 15 minutes.
Maybe a shop vac works for you, once the ground is loosened up enough.
Good luck

Martin

 

[brin]

In Georgia we have heavy clay soil and come across many rocks so when I first used my auger on my 3 pt hitch it would just spin down about a foot or so and I ran into the same problems you mention. I took the auger to a welder and he welded carbide onto the leading edge of the auger and sharpened it with a diamond sharpener and when I tried after that no problem in drilling over 600 post holes for 4 board fence for our farm..hope this helps...I know it's not your equipment but it might pay you to do it for the contractor in your situation.

 

[Ken45101]

If it's smaller rocks (not solid bedrock), I agree the post driver is probably the way to go.

An auger that will cut through rock may work too.

Of course there is always the good old spud bar to manually bust the rock. I have one post that took me 4 hours to put in. I don't have fence up at that point anymore, but I am NOT taking that post out!

As for cleaning out what he has already dug, repeated lifting/dropping the auger while spinning it at moderate speed tends to pull out a good portion of the loose stuff.

Ken

 

[jpav]

Short update.

He came out, got 45 or so of the holes done. Broke off a tooth, and the mounting bolt area for the pilot bit on his 6" auger. Mount broke clean off. This is a purpose built Cat part, so he was going to try and warranty it with the local Cat dealer. I'm going to contact him again today to see how that is going, and try and get the other 15-20 holes left done soon.

On average, only got down about 2- 2.5 feet before it just wouldn't go any more (without rounding out the hole at the top more as he tried to dig down at a different angle to get under whatever was down in the hole). We have lots of rock, and a couple of hardpan layers in most areas. Combine hardpan and rock, and some sand, and you have a pretty solid cement mix to try and drill through

No pictures of his rig, I'll try and remember when he gets back out to the place.

He did mention the hydrodrill guys, and knew it was expensive. $50 per hole is about 10 times what this costs, and at that, I can deal with a hole that takes a little manual cleanout, and only gets down about 2' and change.

The holes that I started a few inches by hand, and soaked with water for a week or so, almost came out clean as the stuff stuck to the auger. Minor cleanout. THe dry holes just had stuff fall back in to be manually cleaned out.