Boart has an extensive experience with drilling and blasting up hole drop raises in one shot without a Machines Roger hole. I would recommend a Machines Roger V30, then you should be able to do 20m-25m reliably in one shot. I have no experience with 30m upholes and would stay away from it. How do you know where the holes end up and how would you find out which way they deviated without allowing for:
1. using some expensive technological gear,
2. the time to analyze it and
3. the time required to bring the drill back in to re-drill the holes drilled off line?
I´ve done checks on the first few metres of upholes with an inclinometer and when you plot the collar dips and azimuths you sometimes see spaghetti.
Downholes are much easier to control especially if there are breakthroughs
Paul Tim

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