A new reverse circulation (RC) drilling system is said to offer a reliable and accurate method for ore body identification and grade control in opencast mining.

Sandvik Mining and Rock Solutions has introduced the new RC sampling option for its Leopard DI650i down-the-hole (DTH) drill rig. Fully integrated into the rig’s platform, the RC drilling system is designed to maximise drill rig utilisation and increases productivity. The option to drill inclined holes with a boom-type drill rig aims to provide an easy and accurate orebody identification method and enables the use of RC face sampling for grade control in opencast mines. An isolated sample route from the bit face to the cone splitter unit ensures no contamination and makes the RC drilling system reliable, productive and accurate.

The Leopard DI650i RC drilling system is equipped with a Metzke RC sampling unit and the drill pipe setup is either 102-mm or 114-mm RC pipes.

The MRH6-RC heavy duty rotary head of the DTH drill rig is designed to be compatible with Metzke RC components. The longer feed beam and robust boom aim to give maximum support for drilling inclined holes with heavy RC tooling. In addition, a hose reel optimises the routing of the sample hose and a new breakout table enables bigger hole sizes and easier maintenance.

For operational efficiency and added safety, the RC system is designed to work seamlessly with full-cycle one-hole drilling automatics and the iCab cabin provides improved visibility for RC drilling. The Metzke cone splitter unit can be lowered for ease of maintenance.

To manage the added weight of the RC system and to increase safety, the Leopard DI650i RC comes with iBalance and iFold options. iBalance monitors the carrier and boom angles for safer tramming, while iFold automatically folds the feed to tramming position for optimum balance.

Adding TIM3D drill navigation system and Driller's Notes measurement-while-drilling options enables the operator to add the sample bag number with comments at a specific location and depth to a graphical user interface inside the cabin for later analysis.

If RC drilling is not needed, the system can be reconfigured to perform the normal DTH drilling production cycle, maximizing utilisation of equipment and offering a faster and more cost-effective way to identify orebodies.

The Leopard DI650i with RC drilling system is designed to be mobile, allowing for easy relocation and the streamlining of mine operations.