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Author Topic: Deep Placer Sampling  (Read 10913 times)

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Offline GPEX admin

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  • Larry
    • GPEX Gold And Platinum Explorations
Deep Placer Sampling
« on: June 25, 2007, 05:15:43 PM »
I feel this area of consideration may be of interest to many - -

Seeking info on home-built apparatus’ which penetrate into the overburden for sub-surface sampling of placer ground.  Any ideas ?  Any plans ?  Any Photos ?

Somebody said that it couldn't be done
But he with a chuckle replied
That maybe it couldn't but he wouldn't be one
Who'd say so until he had tried.

Offline mikeprospecting

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Re: Deep Placer Sampling
« Reply #1 on: July 05, 2007, 01:19:49 PM »
Hi Larry

We used to use a system for cratering that require an explosive method.
Using a three inch camoflag tube, heavy wall pipe, you drive it into the overburden and at regular intervals
you can drop in a small cratering charge. Advancing the tube through solid rock can be accomplished
using a special shaped charge designed to bore hole twice the depth as the charges length. Anyway, the idea can be scaled down and Many times we have man packed the necessary material to pentrated tens of metres.

Adapting the equipment to adapt to a suction pump would not be a huge leap. Six foot lengths that with threaded joints, A 50lbs thumber, Adapters, the list goes on.

I hope you get a basic picture, there a bit more to it.


Offline Whisper

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Re: Deep Placer Sampling
« Reply #2 on: July 08, 2007, 06:37:20 AM »
Hi Mike,
Your process sounds very interesting....would you care to elaborate more?

Offline mikeprospecting

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Re: Deep Placer Sampling
« Reply #3 on: July 09, 2007, 01:15:43 PM »

Think of it as driving a fence post, your attachments are designed to drive the steel tube into the overburden. The shape of the driving point on the tube helps to drive bigger material out of the way. when the tube has been driven in 3-4 ft another section can be screwed on. If large boulders or hard packed false bedrock is encountered there are methods of using explosive charges designed to borehole or to create a cavern.
Hydraulic jacks are modified to remove the tube out of the hole, when blasting is required, you only have to withdraw the pipe to allow some relieve, Setting it off sounds like a cannon going off and lots of smoke out of your pipe. An attachment for hooking up water pressure or suction is not new technology. Samples can be taken at regular intervals, water pressure can also be used to assist with penetration. I'm also convinced that in shallow areas of overburden, I can get a snake to work for washing and vaccuuming the bed rock, Thats another story.

I'm working on some drawings and written procedures and designing different attachments, its a hobby. I'll post info if there's interest because I would like as much input as possible.

Offline gangesex

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Re: Deep Placer Sampling
« Reply #4 on: January 06, 2008, 02:39:28 PM »
Keep your eyes peeled in the Ritchie Auctions  and  Buy & Sell rags for an old well drilling truck. There was a 1960's vintage single axle chevy with a old Bucyrus Erie water well drill for sale up in parksville BC for $6500 OBO on the highway. Thats way you can go thru river cobbles and rockes, etc even in frozen ground without hitting rocks. The explosives idea sounds like too much bullshit to me. Either that, or keep eyes peeled for an old earth auger drill. They do come up, fairly cheap, and you see them used at gas station soil remediations. Those drill have been used forever and lots of old obsolete ones out there if you are patient and don't mind travelling to get the right one. But then you posess the right tool for the job.

Offline Cortes

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Re: Deep Placer Sampling
« Reply #5 on: March 30, 2008, 10:19:01 AM »

Offline bigbarau

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Re: Deep Placer Sampling
« Reply #6 on: March 30, 2008, 11:52:24 AM »
Just checked out the Banka site and there are many good ideas that have been presented. Also this fits more into what small placers need to look for. I agree that it would be nice to have a used water drill rig etcetera, however, can you get it to an osloated site, I don't think so. Working creeks and rivers, or wherever you have to use water transport or "Shanks" pony, compactness and user friendly labour is the best alternative. I have also used  water nozzles on the ends of pipe sections and this works well in gravels, sands and clay materials. Aeration and water is also another alternative that works, again weight and the amount of equipment needed may limit how solated you can go. Remember, in the early days, access was limited to trails cut by the prospector. Today we have many more methods of transport to access even the most remote areas. The small placer miner still has an advantage to making a profit.

I like all of the present ideas and look forward to all of the various inputs. There is never, a bad idea, nothing will work if you dont try. Refinement and patience will yield success. Best of luck to all....


Offline christiansen

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Re: Deep Placer Sampling
« Reply #7 on: July 27, 2009, 12:12:14 PM »
Photo of placer drilling in South Greenland.  <-thinking->

Offline garnetsootheran

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Re: Deep Placer Sampling
« Reply #8 on: July 28, 2009, 07:32:19 AM »
Before investing a huge amount of time and or money on a method for sampling do a lot of reading on sampling. It is general knowledge that the smaller the diameter of hole size the less reliable the sample aquired. Most placer drills (churn drill) used a 6 inch casing and there is a lot of information on correction factors, hole spacing etc that helps a person from repeating errors that others have overcome.
Unfortunately it seems that the most accurate sample is achieved from a large amount of material. This is due to particle size of placer gold - the so called nugget effect in hardrock sampling.
For portability a shovel and good lining bar along with a strong back will get you down 10 feet quite 'easily' lol!!!@*. Be sure to have a good come-along or winch to get the boulders out of the hole. Beyond that a 'small tow behind the truck backhoe' will save the back but they will not go deep and are affected by big rock also.
Rent a bigger back-hoe, it is cheaper to do a weekly rent than a purchase - even if you have the money. Let the other guy keep the maintenance up. It'll do a 10 foot hole fairly easily but has trouble getting rid of the dirt.
A track hoe (excavator) is the ideal way to go as it will go places a rubber tire machine can't and it's digging power and versatility is a great thing for any ground. Rent the biggest you can afford and you will rewarded with lots of valuable information. That 10 foot hole you dug by hand in two days can be dug in 5 minutes, and one day with an excavator will give you a few years of sampling material.
Just remember that if you have a big machine coming to do work, make sure you have the work lined up - more than what you think the machine can do. That thing costs by the hour and if it sits while you think about where to dig your next hole the owner keeps getting paid. Always have a plan 'B' even "C D E F etc.' because things go sideways and it's your dime that pays.
Anyway just my humble opinion.


Offline PlacerPal

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Re: Deep Placer Sampling
« Reply #9 on: July 28, 2009, 08:12:06 AM »

Placer miner friend working his claims in the Yukon as a small miner
this spring bought a small version of a "Ditch Witch" on tracks. The machine
has a auger drill attachment and expandable auger sections in about 3 ft lengths.
I believe the auger drill is 10 - 12 inches in diameter.

He wants to find bedrock which he estimates to be up to 35 ft. along the river.
Permafrost is a problem for him so he hopes to open up some holes to speed melting
of the permafrost and then with his backhoe or cat open up more ground.

He won't be back until late September and until then we won't know how the
Ditch Witch and augured holes to bedrock works out. He works solo and I often
wish I had the time and energy to help him out.

Maybe one of these years...........   :)


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