Mining3, in partnership with global drilling tools specialist Robit and CSIRO, has taken up the challenge to develop an underground percussive drillhole deviation measurement tool.The new system, dubbed as U-sense, is an upgrade of Robit’s S-sense technology (pictured) licensed from Mining3’s Automated String Positioning System. The S-sense system measures the straightness of surface production holes bored by a percussive drilling process and is commercially available for purchase by Robit. U-sense will extend the technology to longhole underground percussive drilling with water flushing.As Mining 3 Technology Leader Dr Sevda Dekhoda says: “Drilling is one of the critical elements in the process of rock breakage. The location (including length and orientation), explosives charge, and detonation sequence of blastholes are strategically selected to produce the most efficient and optimal rock fragmentation.“The consequences of deviation in drillhole trajectories from the designed pattern include build-ups, hang-ups and poor rock fragmentation, and will normally lead to extra drilling, loss of drill strings, ore dilution, ore loss, increased explosive consumption, time wastage, and delays in the chain of production operations. Hence, the impact of blasthole deviations can be felt throughout the production cycle, excavating, hauling, and mineral processing.”This is where U-sense, which is an easy to use capsule that sits within an adapter between the percussive drill bit and drilling tube, comes in handy. It measures the trajectories of the drilled borehole as the bit is retrieved from the hole, then communicates the information with a receiver system mounted on the drilling mast.The measurement module is on standby during the percussive drilling process and commences measurement once the drilling is complete.As the unit is pulled out of the hole, the sensors record inertial information for processing with onboard proprietary algorithms. Once the tool is completely out of the hole, the data are transferred wirelessly for presentation on a cockpit tablet. The plot of actual borehole trajectory information – with respect to the planned orientation – allows the decisionmakers to drill a remedy blast hole or revise the blast design.“Early access to drillhole trajectory information can have a huge impact on reducing mining costs of freezing stopes, creating large oversize, and under-break or over-break caused by blasthole deviation,” Dekhoda said.“In addition, data from the testing unit will be used to develop decision support systems for determining the best way for a production team to modify the pattern if excessive deviation is detected. The availability of hole deviation data – on every blasthole – will enable further research into optimisation of blast designs for different rock mass conditions.”The project Mining3, Robit and CSIRO are working on has two main phases to develop:A validated pre-commercial test unit;Next generation upgrade and testing of the unit through various case studies.Mining3 expects the unit will be available for priority clients (sponsors) in 12 months and can be purchased through Robit.