DRILL & BLAST
Leica J2drill enables accurate hole placement
L
eica Jigsaw J2drill can measure what
the human eye can’t, enabling operators to drill accurately in the right position and to the corect RL the fi rst time, every time
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technology such as GNSS (mixture of satellite-based positioning technologies such as GPS, Glonass, BeiDou and Galileo), the guidance system is able to position the drilling rig over the hole accurately without any markers on the ground. T is eliminates the need for surveyors to mark out the pattern, reducing the risk of injury and resulting in a reduction of light and heavy vehicle interaction on the mine site. In some cases, the accuracy of a guidance system can be less than 50mm (2in). Angle sensors and sophisticated modelling algorithms compensate for any slope variations and predict how the machine will position over the hole even before it jacks up. For angled holes, especially for pre-split patterns, this is even more critical. During the design phase, the collar elevation of the hole is usually estimated or determined via a survey pickup. If this elevation diff ers
signifi cantly to what the drill surveys, then the X-Y position of the hole needs to be moved to the correct location in order to achieve the correct hole toe position. Drilling to the correct toe position is important for pre-split patterns as this defi nes the toe of the wall. If this diff erence in elevation is not catered for, the wall will not be in the right position or instability could result that then requires additional monitoring or control processes. A quality guidance system, such as the Leica J2drill, will compensate for this diff erence and adjust the position of the hole so as to achieve the correct toe position. T is diff erence can occur simply because, in the process of prepping the pattern, the dozer took more material than what had been planned. Drill and Blast engineers often compensate for this by performing a survey pickup just after the pattern has been prepped.
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