Dando’s Callum me as just returned from a visit to customer Green Gold Engineering who are sampling mineral sands in Indonesia.
The geology in the area poses many difficulties for representative sample recovery at high levels with running sands being a particular problem. Ask any driller how the approach running sands and you are likely to be met with a groan or a shake of the head. Standard procedure is to keep the borehole topped up with a head of water in order to attempt to balance the sandy water in the formation and prevent it from flowing back up, and then drill as quickly as possible until you get through it.
However Shane Charlton, drilling manager for Green Gold’s inhouse drilling division ‘InDrill’, was determined to recover samples from the flowing sands where geologists believe much of the target minerals may reside. Supported by Dando with a number of modifications and some prototype ancilliary equipment, he is not achieve very high levels of recovery from surface to end of hole. Typically he is sampling to around 13-15m of sand until clay is encountered, and then continuing a few more metres to prove the end of the alluvial geology. The team then packs up and hand carries the tools through the jungle to the next drill pad, with the nimble Terrier rig weaving carefully through trees and leaving the wooded area largely undisturbed.
See more of the operation in this short video clip.