BLASTING
AVALON SUCCESSFULLY AND SAFELY DELIVERS HIGH PROFILE GEOTECHNICAL AND CONSTRUCTION BLASTING PROJECTS.
Our New Zealand certified explosives handler / construction blaster has over 30 years experience and our engineering geologist graduated in 1987, so you can be sure we’re on top of our game. We have a wide range of drilling equipment, explosive types, detonation systems and blasting techniques at our disposal. For example:
MANGOREWA GORGE
MAUAO, MT MAUNGANUI
Following extensive fires in 2002 a large unstable rock mass was revealed high on the bluff above the campground. Fresh spalling indicated imminent failure of 250 tonnes of rock in 5 large boulders, each with the potential to run far into the campground.
An on-the-spot geotechnical assessment forced Tauranga District Council to act immediately; there was only one option – scale the loose rock. The camp was evacuated and fifty shipping containers were brought in as temporary barriers.
AVALON devised a deck loaded drill and blast plan to split the rock into small pieces which would roll with minimal energy. A plant was quickly mobilised and our two rigs drilled hundreds of metres of shot holes in just three days.
Amid intense media coverage, high security and OSH scrutiny, AVALON'S spectacular blast safely eliminated the hazard only three weeks after it was first identified.
AVALON received an unsolicited letter of thanks from TDC's CEO, congratulating us on our professional operation.
MANAWATU GORGE
Major flooding in 2004 created a large number of slip faces with unstable rock masses and trees hung up high above the State Highway.
AVALON was called in by Transit NZ's consultant engineers and efficiently carried out drilling and blasting at five sites, successfully removing the tree and rockfall hazards.
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RUAKURI CAVE, WAITOMO
AVALON excavated hundreds of tonnes of rock to create a 30m tunnel connecting two areas of show cave. We also constructed 250m of suspended walkway above the cave’s underground river. A limestone passage floor had to be lowered to achieve levels for wheelchair access.
Ruakuri cave abounds with sensitive glow-worms and beautiful but delicate stalactites and calcite formations. Work had to be carried out under very strict resource consents with vibration and air quality monitoring. Because of our reputation for handling protected environments, AVALON was consulted for a blasting proposal. A compressor on the surface powered our drilling plant via a 70m vertical borehole. AVALON'S crew had to access the site by "tubing" down the stream-way in wet suits before changing into dry gear for the long and muddy shift underground. Very lightly charged holes with frequent intermediate relief holes and a "Nonel" detonation system were planned to minimise airblast. The blast was successfully fired late one night. The seismograph recorded a maximum 16mm/s vibration; 4mm/s below the resource consent's allowable limit. Air quality remained acceptable and no formations were damaged.