By implementing initiatives to exceed targets with the same or lower costs, such as those mentioned in Part 1 – Starting with the ‘small stuff’ ‘ and Part 2 – Improving blasthole drilling practices, allows funds to accumulate for other, bigger programs that require not just ideas and time, but money too. In Part 3, we look at drill rig optimisation.
Optimising drill rigs
While more expensive to purchase, operate and maintain, using big drills means drilling less holes – patterns can be drilled quicker and less explosives accessories are required. So despite their operational costs, the cost of achieving the end result – blasted material – becomes cheaper than if the same amount of work had been done with smaller drills.
However, this approach presents challenges if a mine has varying blast requirements and/or if reducing dilution and ore loss are key objectives. If a blast is designed around the capabilities of a specific drill rather than designed to maximise the explosive energy, it can result in a sub-optimum blast to the detriment of subsequent mining activities and project costs.
Solutions–focused drill and blast teams are finding ways to overcome this issue by optimising rigs to drill a variety of hole sizes, effectively enabling them to satisfy a wide range of blast parameters but without the additional operating costs associated with running multiple pieces of equipment.
These optimised rigs use multiple bit diameters and can perform angled drilling to suit varying ground types, final wall designs and bench heights. The capability to drill a wide variety of blasthole sizes means the drill and blast team can get the most efficient work out of the explosives. This will allow them to deliver the best downstream benefits to the mine, such as better rock fragmentation to improve dig rates and crusher throughput, optimal muckpile profiles and better final wall stability.
Bowen Basin case study
This approach has been delivering value in the Bowen Basin where ADB engineered modifications to a standard Atlas Copco Pit Viper 275 (PV275). The engineering improved the rig’s flexibility enabling it to compete against its larger and more expensive cousins.
The optimised PV275 drills three different size holes – 229mm, 251mm and 270mm. Its standard set up is just 251 and 270mm. There is no requirement for additional equipment to drill thinner holes and custom-made rods also facilitate increased depth which enables the rig to drill 20% deeper than the standard PV275 model and with equal efficiency.
In short, a forward-thinking, team-based approach and a dedication to doing things better means that more work can be done with the same – or even fewer resources – and less cost.