While we wait for the results from the recent aircore/slimline RC drilling program results that are expected any day now (Early August), and plenty more pending results from the recent completion of Diamond Drilling at Minos Prospect (3 diamond tails drilled for a total 593m).
I thought that it might be a bit of fun to list below the difference between the common drilling techniques;
Auger
Auger drilling is done by rotating a helical screw into the ground with the earth being lifted up the borehole by the blade of the screw.
They range in size from small hand-held units to somewhat larger ones mounted on small vehicles.
Auger drilling can only really be used where the ground is soft but it is both cheap and fast, making it suitable for its main use as an initial geochemical reconnaissance technique.
Rotary Air Blast (RAB)
Moving up to the next size, we have rotary air blast (RAB) drilling, which is the most common shallow drilling method.
This uses a piston-driven “hammer” to drive the drill bit into the rock, creating rock fragments, or “chips”, that are lifted to the surface by compressed air.
RAB drilling is a quick method of drilling many holes in a short period of time though it may produce lower quality samples due to the way that the rock chips are blown up the borehole.
Aircore (AC)
Aircore drilling is preferred over RAB as it tends to provide more representative, or accurate, samples.
It uses a three-bladed steel or tungsten drill bit with a hollow drill rod to penetrate the weathered layer of loose soil and rock fragments.
Once drilling is complete, compressed air is injected into the space between the inner tube and drill rod’s inner wall to flush the cuttings to the surface.
This makes samples from aircore drilling less prone to contamination, though it is generally slower and more costly than RAB. Aircore is also unable to cut through fresh rock.
Aircore drilling is an Australian invention. It was invented by Western Australian-based Wallis Drilling to solve a problem drilling mineral sands.
Reverse Circulation (RC)
Reverse circulation, or RC drilling as it is more commonly known, and is a popular technique for mineral exploration.
Like RAB, RC drilling uses a piston-driven “hammer” to drive a tungsten-steel bit into the rock, though the use of larger rigs and machinery allows holes to be drilled much deeper.
It also has similarities with aircore drilling in its use of compressed air to drive the dry rock chips up the inner tube.
It is also an Australian invention, RC drilling is ideally suited for exploration, as it delivers contaminant-free samples. This also makes it suitable for infill and extensional work.
It is also used in grade control because of its effectiveness in defining boundaries between ore bodies and waste rock.
RC drilling is slower and costlier than the previous types of drilling.
Diamond Drilling (DD)
The most expensive form of drilling is diamond drilling, which uses a diamond-impregnated drill bit attached to hollow drill rods to extract a continuous cylinder of rock.
Despite its cost, diamond drilling has several advantages over RC drilling.
It is capable of drilling down to several kilometers in depth, it can penetrate hard rock and it returns the most accurate samples, as its core samples can show the actual veins of a mineral and their precise location in the ground.
This makes diamond drilling suitable for acquiring structural controls on the mineralisation.
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So with the above noted we are all keenly awaiting the upcoming AC results with much anticipation from Minos and truly hope to see some good gold grades extending along strike from our recent brilliant RC results!
These results will hopefully lead to a new and great RC and DD program!!!!
IMHO this is only the very beginning of a beautiful high grade discovery, especially at the current massively discounted share price!
GLTAH+DYOR
P.s. IDA should hopefully now have PLENTY of cash in the bank from the exercising of options!?!?!!?
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