Rock breaker info.

[Jenki]

Hi all, I'm after any info you have from experience of what can be achieved (volume over time) breaking bed rock.

Our plot is on the granite slabs up in Caithness.

The percolation test failed with rock at 400mm depth. Recent investigations of the water main showed that rock is 300mm deep at the front of our field. ( The main was laid in blasted trenches 800mm deep.)

 

So I know I'll need to rock break to install treatment plant. But I've no experience with machine attached rock breakers.

If I install a marsh shallow dig, it's still around 2.6m X 1.6m x1.6m mostly rock. So trying to get an idea of how long it will take to remove 6 cube of rock.

 

The figures will help decide weather to rent or purchase a breaker for a machine. With a view to selling at the end.

 

I've had figures of £300+v/week to rent. 

 

Any info would be appreciated.

 

 

 

[markc]

Get a 13 to 20 ton excavator in with a pecker and save yourself a lot of work. Have it done in a couple of days

[Cpd]

1 hour ago, markc said:

 

Get a 13 to 20 ton excavator in with a pecker and save yourself a lot of work. Have it done in a couple of days

 

This is totally right, I spent years jackhammering all sorts of stone and granite really is a show stopper when it comes to hand held equipment, we used to have it blasted in remote locations but if you can get in a big machine then that’s the best option. 

[saveasteading]

2 hours ago, Jenki said:

rock at 400mm depth. Recent investigations of the water main showed that rock is 300mm deep at the front of our field

 

What is under the 300mm of rock?

 

I assume you also need to break the  rock for a soakaway. The ground beneath  needs to be permeable or it will not work.

If getting a pecker in it is worth doing more work at the same time.

 

 I agree with the the recommendations above. Big machine and a pecker. Even if it was blasted first I am guessing that the rock would still be tightly in place and need a lot controlled force which a hand breaker will not have.

 

The pecker may do it all in a very short time, but to try with a small breaker will take days or even weeks.

This is not a diy job, so it is worth talking to your local hire company or contractor, who should know the ground and the best machine.

[Ronan 1]

I'm currently breaking basements for 3 sperate apartment blocks all in Granite. All circa 15000m3 each.

 

Big machine will pay for itself  and would take that out in a day BUT most hire places that rent out hammers with their machine put smaller hammers On so it's less abuse on there machines and prolonged hire.

 

Minimum 20 ton machine with a 3 or 3.5 ton hammer 

 

P.s or get a crowd in to hydraulic crack it, they'd also get it out in a few hours 

Edited February 13, 2022 by Ronan 1

[Jenki]

12 hours ago, saveasteading said:

What is under the 300mm of rock?

Sorry, Rock is at a depth of 300mm, under this rock is lots more rock?.

Was never intending a hand breaker, trying to get an idea of time with a machine.  Rock breaker around £400 / week to hire plus machine so say £1000/ week.  You can buy rock breakers for around 2K. was wondering is the maths suggest buy and re sell later, or just take the hit with the hire costs.. 

I may well  have to break out the trenches  for pipes and soakaway so may need it around a bit.

[Jenki]

13 hours ago, Cpd said:

This is totally right, I spent years jackhammering all sorts of stone and granite really is a show stopper when it comes to hand held equipment, we used to have it blasted in remote locations but if you can get in a big machine then that’s the best option. 

The water main running along my field edge was blasted. (1950s)  they got it down to 800mm.  and used the spoil for backfill

 

14 hours ago, markc said:

Get a 13 to 20 ton excavator in with a pecker and save yourself a lot of work. Have it done in a couple of days

this is the info I need. Thanks  - what's the learning curve like using the pecker?  I've experience with 360 machines, just not using the pecker attachment,  

my other option would be to hire with operator, and follow around clearing the broken rock with a backhoe to speed up the process?

I could have the site ready, the trenches dug, area for soakaway, treatment plant cleared and  levels set etc, then get the big machine in to do all required breaking in one go.?

 

 

[Declan52]

11 minutes ago, Jenki said:

The water main running along my field edge was blasted. (1950s)  they got it down to 800mm.  and used the spoil for backfill

 

this is the info I need. Thanks  - what's the learning curve like using the pecker?  I've experience with 360 machines, just not using the pecker attachment,  

my other option would be to hire with operator, and follow around clearing the broken rock with a backhoe to speed up the process?

I could have the site ready, the trenches dug, area for soakaway, treatment plant cleared and  levels set etc, then get the big machine in to do all required breaking in one go.?

 

 

Fairly easy to use it you can already handle a digger controls. Will depend on the digger how the hydraulics work. Some use a foot pedal, others a button on the stick.

[markc]

As above, if you already have a backhoe (assuming it’s 3cx or similar size) then a breaker for that will be ok. Pecker is easy to use but knock he’ll out of the machine , 3cx we’re known for shattering glass or it falling out while pecking.

granite shatters so pecker away from yourself and have some boards propped up to catch most of the flying debris

[Jenki]

20 minutes ago, markc said:

As above, if you already have a backhoe (assuming it’s 3cx or similar size) then a breaker for that will be ok. Pecker is easy to use but knock he’ll out of the machine , 3cx we’re known for shattering glass or it falling out while pecking.

granite shatters so pecker away from yourself and have some boards propped up to catch most of the flying debris

I've just got myself an old Ford 550. I think a pecker will destroy her?.  So resigned to hiring in a big machine and pecker.

[Dave Jones]

minimum 13 tonner.

 

depending on the rock, it may be quicker to drill and charge it with non-explosive splitting charges to speed the pecker along.

 

https://www.sms-wales.com/nxburst-faq.htm

 

 

[saveasteading]

Rock with more rock under it. Can you advise what rock is under the rock, and why it doesn't seem to be a problem?

 

The outlet from the digester is about 100mm below the inlet and then you have drains running downwards (obv). Is the rock going to be an issue all the way or can you use slopes?  Final outlet to soakaways or burn?

[Jenki]

Just dragging this back up as time is getting closer.

 

@Dave Jones Mentioned Chemical Charges.

 

Has anyone used https://www.dynacem.pl/uk/non-explosive-demolition-agent-dynacem-feedback.html. non explosive Expanding grout?  

To Recap- I need to remove around  8m3, 3.8M long * 1.8M wide * 1.2M Deep.

 

 

 

On 14/02/2022 at 18:46, saveasteading said:

Rock with more rock under it. Can you advise what rock is under the rock, and why it doesn't seem to be a problem?

 

The outlet from the digester is about 100mm below the inlet and then you have drains running downwards (obv). Is the rock going to be an issue all the way or can you use slopes?  Final outlet to soakaways or burn?

Sorry don't know how I missed this . To clarify the rock I'm dealing with is granite, part of the Caithness granite slabs, namely lower flagstone group fishbed?  so its thick bedrock. so its all a problem (or at least the 1.2M deep I need to remove.

With regards to flows there is some variations in land levels, so main house to treatment plant and then to soakaway to watercourse should work with little / no additional breaking out.   The pods some 60M

away may end up being pumped to the Treatment tank.

 

[markc]

Morning, I haven’t used them but as you are in bedrock there is nowhere for the expansion to take place. Expanders, just as blasting require an open face or side to allow the rock to expand and move somewhere otherwise you just get micro fractures.

hydraulic expanders work well but it all depends on what rock you have, do you know what it is you are wanting to break?

[Jenki]

1 hour ago, markc said:

Morning, I haven’t used them but as you are in bedrock there is nowhere for the expansion to take place. Expanders, just as blasting require an open face or side to allow the rock to expand and move somewhere otherwise you just get micro fractures.

hydraulic expanders work well but it all depends on what rock you have, do you know what it is you are wanting to break?

 

The info they supply on breaking bed rock is to create an open face by either  drilling holes at an angle(#2) then the open face is the top surface, once this is out you then have open faces to work with , the other option is to chain core drill, a slot essentially a trench thus creating an open face.

The later option seems the most sensible, but core drilling 1.7M Wide trench by 1.2M deep (in  multiple depths) seems like arduous work.

I will only know for sure what I'm dealing with at the end of the month, but was thinking of trying this on a trial basis to see how I get on.  

 

 

 

[markc]

26 minutes ago, Jenki said:

 

The info they supply on breaking bed rock is to create an open face by either  drilling holes at an angle(#2) then the open face is the top surface, once this is out you then have open faces to work with , the other option is to chain core drill, a slot essentially a trench thus creating an open face.

The later option seems the most sensible, but core drilling 1.7M Wide trench by 1.2M deep (in  multiple depths) seems like arduous work.

I will only know for sure what I'm dealing with at the end of the month, but was thinking of trying this on a trial basis to see how I get on.  

 

 

I would drill the initial holes at an angle too to break out a central wedge, then it’s much easier to widen. Old fashioned method of drilling holes then knocking in wooden stakes and soaking with water to cause the expansion.

definitely worth hiring a proper rock drill, hopefully you have some of the softer rocks .. if it’s granite then you are in for some hard work.