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Up-hole Sludge Drilling Sample (6 replies)

Bob Mathias
9 months ago
Bob Mathias 9 months ago

Can anybody offer any solutions to getting a reasonable sample from uphole sludge drilling in an underground mine (with the emphasis on reasonable - not perfect)?

9 months ago
Oberstorm 9 months ago

Yes it's possible. Firstly measure your drill rods - if standard 1.8m then take two 900mm samples (paint mark at 900 on the rod),

We used a sampling cone - a funnel with a 1.2m diameter opening that funnels down into a 20 liter bucket. The funnel (which is on a stand) is only about 900mm high

Put the funnel on the floor directly under the drill hole. Drill carefully so that the sludge doesn't get thrown around. A standard 40mm blast hole should give you a few kilos of sample.

Also if you have a narrow ore zone, first drill a hole to estimate how far in is the ore. (For instance, a tin greisen lode is black compared to the white granite. If the greisen is approximately from 1.2m to 1.8m down hole then that's where you sample - from 0m to 1.2m go into 1 sample bag and 1.2 to 1.8m goes into the ore sample. Mine tech also needs to document if broken ground in-hole etc - any identifiable sources of contamination.

With a trained mine tech who can log ore/waste and a portable XRF you can have results within a few hours of the hole being drilled and if it's a ring hole, you have enough info to say, bag off the bottom of the hole that's extended past the ore zone to stop over break in the firing.

Also have driller wash out the hole at the end just to clean sample and sludge waste off the drill mast and assembly between samples.

Carmen Ibanz
9 months ago
Carmen Ibanz 9 months ago

Use a sample collection funnel on the ground. Funnel has opening 1.2m diameter and funnel into a 20litre bucket. Flush between samples.

Victor Bergman
9 months ago
Victor Bergman 9 months ago

You could apply Autosampler that is an automated sample collector with cone type splitter and rotating sample cutter blades. You can use filtering sample bags for wet sampling. Here's a link: http://is.gd/648e4r

9 months ago
Gruppen 9 months ago

I agree with you using a funnel and a bucket, and even though the quality of sludge hole sampling is not great, they are very cheap and can be a good guide for production. I suggest you use more water pressure than needed for the drilling, in order to flush rock chips that can remain in the hole and contaminate samples (especially for low up dips).

Marshal Meru
9 months ago
Marshal Meru 9 months ago

Yes to the funnel and bucket. Seeing the method is doggy I try to get what good info I can. I would also include one of my geologist volunteers to log the hole while drilling occurs. This is important as the geo can then log the different rock, alteration, mineralization, etc. while drilling occurs i.e. stopping the drill to measure the length when an important boundary is crossed. From this you can get some reasonable 3D info.

Paul Morrow
9 months ago
Paul Morrow 9 months ago

There is a system around with a collar that sits around the drill rod with a hose running down to a collection system. I used it at Yilgarn Star in Western Australia many years ago as a junior geologist and it gave a reasonable result. I have a memory that someone holds a patent on it but, having never seen it at trade shows or conference since, wouldn't know where to find them.

It had the advantage of effectively putting the funnel close to the face; however poor recovery (similar to the larger funnel) and a very wet sample were still issues, especially at the sampling stage.