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Author Topic: Finding the depth to bedrock  (Read 22302 times)

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Offline jayjayccr

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Re: Finding the depth to bedrock
« Reply #10 on: March 28, 2014, 02:25:17 PM »
When using a probe, is it necessary to use a mallet to drive it down or can this be done rather easily without.  Let's say, probing gravel bars?

Offline mcbain

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Re: Finding the depth to bedrock
« Reply #11 on: March 28, 2014, 07:55:32 PM »
Hi. Most of the above are right to some extent.On my claim that has been drilled by the pipelines i was told bedrock was at 75 feet not following exposed rock on hillsides I have found 4 locations with bedrock showing on the river bottom at the surface in old channels.Takes a lot of work and exploring.Luck Mcbain.
I started out with nothing Istill have most of it.

Offline nuggetnut

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Re: Finding the depth to bedrock
« Reply #12 on: April 01, 2014, 12:46:29 AM »
There is a geophysical profiling method we used. It is an Induced Polarization (IP) 2D Resistivity method. The unit is by Schlumberger Array. It runs similar to seismic, but cheaper.

You'll find some other interesting geophysical information on a company called GDD Instrumentation. I never used them but they have neat gadgets to expand your options. One unit is called a "Beep Mat" which I always thought could pick up concentrations of magnetic black sand.

Offline The Driller

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  • Coring where no man has cored before
Re: Finding the depth to bedrock
« Reply #13 on: August 28, 2014, 09:56:45 AM »
The only way to determine depth to bedrock and confirm it is bedrock NOT just a hard layer is to drill. Even the fancy electronic means MUST be backed up with drilling........

Auger drill with solid stem for shallow depths

Auger drill with hollow stem for greater depths and/ or groundwater

Problem with augering is that a true sample of the bedrock usually can't be obtained.

Cable tool drilling/ Spudding is cheap to operate/ or buy but slow but will give you samples of everything.
Reverse Circulation drilling is cheap per foot but the drill is expensive to buy (Can be used for a 43-101)

Diamond Drill coring is more expensive per foot but cheaper to buy the drill WITHOUT the right drilling fluids placer sample WILL NOT be captured.


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