Mighty River Power recognised the versatility of Alton Drilling, engaging us for a range of projects over a 3 year period.

2001 – Arapuni Dam – Abutment Investigation Drilling.

Drilling of angled boreholes from the abutments of the dam for the purpose of assessing seepage and grouting conditions. Scope included high quality core recovery, casing, water testing, grouting of completed holes and standpipe installation. Installation of Piezometer packers down to depths of up to 100 metres.

2001 – Arapuni Dam – Bore Holes for Fissure Grouting.

Directional drilling from the base of the dam aimed at specific target areas within the dam foundation. Holes intersected areas that discharged water at high pressure. Holes were then fitted either with drainage relief or grout fittings. Job required excellent core recovery whilst working in sometimes difficult conditions.

2002 – Arapuni Dam – Installation of Fissure Monitoring Piezometers.

Drilling from the outside of the dam at sites close to the gallery entrances. Holes to intersect defects in dam structure and high pressure flows encountered. Drill holes then fitted with borehole packers and vibrating wire pressure transducers withAltonproviding assistance with instrument installation.

2002 – Arapuni Dam – Drilling & Pressure Grouting of Diversion Tunnel Intake.

Drilling and low pressure grouting to fill voids behind the concrete lining of the diversion tunnel.

2003 – Arapuni Dam/Hinuera Quarry – Foundation Enhancement Project – Site Trials.

Pre-drilling bore holes required for trials and on completion of trials, capping the holes and clearing the site.

2004 – Taupo – Control Gate Structure – Installation of 3 piezometers.

The installation of two standpipe piezometer nests, one on each bank on the downstream side of the structure, and one standpipe piezometer in the middle of the river, attached to a downstream pier.