There was a pdf I used to use that had some info on the costs. But it might be way out of date now. Have seen figures of AU$200 per metre mentioned recently for Diamond drilling. Also I think it doesnt include the one off mobilization and demobilization costs which could be pretty step for remote areas. Also not sure of it includes consumables.
If you want to be sneaky you could ring a drilling contractor and ask for a quote ;-) Although I have tried that for commodities on Alibaba and no one ever replies :-(
