MAR bores set to go
Construction of the two bores for the recharge trial in the Makauri aquifer have been completed at Kaiaponi Farms Ltd.
The first bore was a small diameter pilot bore and determined that aquifer gravels were present at a depth of 69metres.
The smaller pilot bore was tested using air lift to pump water out of the bore to assess what reaction was seen in nearby bores.
A monitoring bore situated 190metres away responded to the drawdown and it recovered quickly after the test.
Acting shared services science manager Dennis Crone says it was pleasing to note that a bore 190 metres away showed the water level falling while pumping and then recovering when pumping ceased.
“The bore itself recovered after 7 minutes and the monitoring bore recovered within an hour of stopping the pump test.
“This was a good result and provided confidence that the site for the injection bore does have the characteristics required for the trial and we could proceed with drilling the larger diameter injection bore. “
The main injection bore, constructed 25metres from the pilot bore, was completed this week drilled to the same depth as the pilot bore.
“The injections bore is now ready for developing and testing following insertion of the liner and lifting of the casing to allow the screen that is at the bottom of the liner to be exposed to the gravels,” says Mr Crone.
Testing of the main bore should be complete by 12 May.
Weather has slowed progress on construction but the project is still on track to start the trial in May and allow the planned 100 days of injection to be completed before 30 September.
For more information on MAR bores
The insertion of the PVC liner into the steel casing of the main bore. The drilling rig was rearranged to allow the larger diameter.
Makauri aquifer gravels were found in a seam that was 3 metres thick at a depth of 69 metres below ground level.