Good idea. A variation of RC drilling is successfully used underground for grade control at Kiruna Mine, Sweden.

Thank you for your comment. What is the variation?

I studied the approach about 16 years back by visiting the Kiruna Mine. Contact the Geology/Grade Control department at LKAB Mine, Kiruna for more up-to-date info. LKAB is highly advance organization and you may pick up better techniques for sampling and blasting. Soon there is going to be a conference at Stockholm, which has provision for a visit to Kiruna Mine.

Trust this helps.

I have not work underground before, but RC drilling underground is a good idea if all the constrain (space, position of the rig, noise, dust, sample quality, etc) can be meant. It can give confidence in the resource.

I know of at least one major gold miner who gave this a go in WA some years ago. I believe it was a technical success but operational failure due to access issues and production rate. I don't know if some of those involved can comment?

UG RC was trialled at Telfer during the feasibility study. Due to dust concerns, the holes were drilled wet, so there was always some suspicion about sample quality - mainly due to capturing the sample. The rig and compressor was also diesel powered so there was ventilation issues to consider as well. I know there were several RC/DDH twins completed as a comparison, but I was unsure of the results. I know one member of this group who may remember.

Thank you very much for the comments so far - very interesting! If anyone else can contribute, please do?

In 1999/2000, an UG RC drill programme was carried out with great success at Cullinan Diamond Mine (aka Premier). A small drill built by CUBEX was used initially to drill -12 inch diameter holes, dry. A dust collection system was fairly effective to reduce the dust emissions underground. Later on the drill was converted for reverse flood to reduce diamond breakage. The compact rig could drill in any direction up to 300m as the mast could be anchored to the roof.