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Location: Darwin , Australia
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Locating Rocks Underground

09/21/2015 8:18 PM

Comrades, need technical advice.

Am working on a project to install gas lines underground for an LPG reticulation network. The challenge we have is there are no underground drawings to show if there are rocks present underground thus costing for breaking rock if we do encounter rocks is unknown.

What kind of tests are required to locate rocks underground and in the path of where we wish to run the gas lines.

What kind of tests are available to confirm how thick and wide the rock is?

Best Regards Ronald Nawa

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#1

Re: Locating Rocks Underground

09/21/2015 8:27 PM

Welcome to the real world.

Your question is borderline comical.

GPR - Ground Penetrating Radar Detection - CNI Locates This will work, but asking local residents or geologists may help, but not much.

Since we have no clue where you are, there is no way to even guess at the geology of your area.

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#2
In reply to #1

Re: Locating Rocks Underground

09/21/2015 9:04 PM

Yes indeed,( Real world)

Thanks for the GPR information. Local knowledge and geologist noted

This project is happening in Darwin, Australia.

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#13
In reply to #1

Re: Locating Rocks Underground

09/22/2015 11:13 PM

Will it detect human and animal bones,skeletons etc ,if so it will help police to locate buried bodies.

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#14
In reply to #13

Re: Locating Rocks Underground

09/22/2015 11:29 PM
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#17
In reply to #13

Re: Locating Rocks Underground

09/23/2015 8:42 AM

In war torn countries nobody know where/how dead bodies were disposed,you can't scan thousands of acres is there any aerial detector like aircraft for this.

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#3

Re: Locating Rocks Underground

09/21/2015 9:24 PM

GPR is one way. Another is acoustic...

https://en.wikipedia.org/wiki/Acoustic_location

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#18
In reply to #3

Re: Locating Rocks Underground

09/23/2015 9:07 AM

I know for a fact there is at least one very big rock in Aussie. Is that one in the way ?

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#4

Re: Locating Rocks Underground

09/22/2015 12:12 AM
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#12
In reply to #4

Re: Locating Rocks Underground

09/22/2015 11:20 AM
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#21
In reply to #4

Re: Locating Rocks Underground

09/24/2015 8:54 AM

Good Point. Will pursue this angle with talks with the NT government for surveys done in area of concern.

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#5

Re: Locating Rocks Underground

09/22/2015 2:38 AM

The question is how deep does your pipe lines go?

If not greater than 18", you may use soil or rock sampling method at ease.

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#6

Re: Locating Rocks Underground

09/22/2015 7:25 AM

I have to question why a subsurface survey wasn't performed during the intiial stages of the design work? That is what is typically done, not during construction.

Yes, GPR or Sonic mapping is the way to go, as it is non-destructive and won't disturb the insitu conditions. Less costlier than standard soil and rock borings.

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#20
In reply to #6

Re: Locating Rocks Underground

09/23/2015 9:26 PM

C'mon Capitan moosie, everybody knows that in the northern hemisphere everything is right side up and down under everything is topsy-turvy.

In the northern hemisphere you got bedrock covered by topsoil and down under you got topsoil covered by bedrock.

So,

When your doing construction, its a good idea to know where all those rocks are at hiding in that topsoil.

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#22
In reply to #6

Re: Locating Rocks Underground

09/24/2015 8:59 AM

Appears we may have not been asking the right questions to lead us to the right people. Area had previous constructions thus a report is likely available and somewhere.

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#7

Re: Locating Rocks Underground

09/22/2015 8:17 AM

Comrades? Are we still in the cold war? And NO i do not mean a war fought in winter.

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#19
In reply to #7

Re: Locating Rocks Underground

09/23/2015 10:09 AM

Oh, get over your Red Scare paranoia, the word just means 'kind-of-friends, or at least acquaintances.' It's not even Russian, it's English, although little used outside of the phrase 'comrades-in-arms,' or when making someone 'sound' Russian without making then have to try and pronounce товарищ (tovarishch).

(By the way, it's not that hard to pronounce, toe-VAR-ish. To be more accurate, the i should sound halfway between the i of 'it' and the e of 'keen,' but due to regional dialects, it can be anywhere from soft i to hard e to schwa (the 'mumbled' vowel that doesn't sound like any vowel in particular, shown as an inverted e in dictionaries) to completely swallowed, making the word into the two sylable toe-VARsh.)

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#8

Re: Locating Rocks Underground

09/22/2015 8:30 AM

Gas retic in Aus!!

You've got bigger problems ahead than rock!! The NBN cowboys can make a mess of anything that you can do properly. Once you cut a trench, they will install over, across and even through your lines.

(NBN Is an Aus jargon that might not translate overseas. Basically federally mandated communications program being installed by lowest contract cost contractors using underground boring, rippers or direct burried with no marker tapes or above ground identification.)

Most contracts of this nature that I've seen have quotation based on a predicted rock proportion with% variance for rock that is encountered. Specifier usually provides base line prediction and you quote rate for variance.

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#9
In reply to #8

Re: Locating Rocks Underground

09/22/2015 8:37 AM

Thanks Mate, for the heads up and inform on quotation based on rock proportion.

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#23
In reply to #8

Re: Locating Rocks Underground

09/24/2015 9:05 AM

Dead Right. Was with a Civil contractor in the heart of Darwin CBD. Excavation to open up an area. What we saw as they went under was beyond belief. Utilities not showing in the Dial Before you Dig report were everwhere. Over, under and across.

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#10

Re: Locating Rocks Underground

09/22/2015 9:55 AM

First I would talk to any construction company or horizontal drilling company that has worked in the area and they will be a good resource.

What does your staff geologist have to say about the earth you will have to work in?

Have you done this type of work before? If you have, where?

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#16
In reply to #10

Re: Locating Rocks Underground

09/23/2015 8:33 AM

See #15 if no geologist on staff or other contractors who have worked the area.

Best start if nothing is done is to get the oldest geological history of the area you can. That way you can get an idea of how the area was formed which should give some ideas of what you may run into- hence, see #15. They should have the information.

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#11

Re: Locating Rocks Underground

09/22/2015 10:56 AM

I would think that since pre-project testing of the area was not done that would have allowed for best-case installation route(s) then locating below surface rocks during construction will require mechanical digging and physical discovery then mitigation.

I seriously doubt re-routing of an already mapped underground LPG installation in progress would be economically feasible especially if dealing with right-of-way permissions and fees.

If you are installing underground pipe along the required route(s) to service customer(s), altering that route because there is a rock located in the path does not seem logical or cost effective.

If you are going cross country or throughout a subdivision or township with a main supply line and/or laterals but have not already identified the underground obstacles, the delay incurred to perform below grade testing during construction and the delay caused by re-routing the pipeline will be catastrophic.

Is this another "Fast-Track", "Engineer On The Fly" project? If so; Brace yourself for overwhelming cost overruns.

If you are just trying to avoid digging equipment damage I would suggest using ground penetrating radar or sonar as has already been suggested.

The needed equipment can be leased or rented.

If you can get access there is available advanced satellite imaging that reveals detailed underground topology. (A call to the Australian government will yield good advice and some answers as to what is available for the area.)

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#15

Re: Locating Rocks Underground

09/23/2015 3:54 AM

I don't know much about archaeology in Australia but try your local university archaeology department. They will have geological information on the area you are working and, if there has ever been a local dig, may already have ground maps. At the very least they will know about ground penetrating sensing equipment and which is the most suitable for your location and the depth you are working to. With luck they could have the equipment available and be prepared to do a deal where students learn how to operate the equipment and interpret the results while mapping your pipe routes. It is certainly worth proposing this to them. Most universities are strapped for cash so there will be a fee but much lower than getting a commercial outfit to do the work. Your biggest problem will be getting universities to work within commercial deadlines. In the UK no pipe laying or major development can take place without first having an archaeological assessment, and a full dig of any site found, which the developer/contractor must fund.

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#24

Re: Locating Rocks Underground

10/05/2015 1:56 PM

OK, but what diameter of what material of gas line do you want to place how deep?

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