The likely culprit behind a seeping, 98° muddy geothermal outbreak in Rotorua’s city center has been revealed.
It is suspected that a deep fracture in a geothermal drilling is allowed boiling mud and steam to burst through a traffic island in the CBD on Wednesday and to nearby Lake Road – which remains closed. This type of opening is known as a fumarole.
The affected area was not a common site for hot fumaroles or wells, Rotorua Lakes Council geothermal inspector Peter Brownbridge said in a meeting on Thursday, and the council was working to extinguish the faulty well.
“In particular, we located one well that we believe has a broken casing at depth,” Brownbridge said.
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Matthew Martin/Stuff
A rupture in a borehole is thought to have released steam, mud and hot water from a well and forced its way through the surface of Lake Rd, Rotorua Lakes Council geothermal inspector Peter Brownbridge said.
“The water was 98°C on the surface and kicked up the clay and silt coming from great depths, so that indicated it was more than just a naturally fed fumarole.”
Rotorua Lakes Council had been monitoring the situation and said work was underway to block private drilling.
“When the well was extinguished this morning, it had an impact on the flow of water from the fumarole, suggesting that a fault in this well would likely allow steam, mud and hot water to escape from the well and create essentially sufficient pressure outside. cause the well to push under the well and make the fumarole,” the council said.
“A drilling rig has been set up over the bore, which undergoes a deep cooling.
“Once the bore has been quenched we will be able to better understand what type of fault caused the fumarole, but at this stage it is suspected to be a fracture deep in the drill pipe.”
Fulton Hogan had been on the scene Thursday with four trucks, including three vacuum trucks, to clean the area and prevent sediment and polluted water from entering the nearby Utuhina Stream.
The surrounding road was checked for any instability or erratic movement, which had not occurred so far.
The portion of Lake Road would remain closed to traffic, which will be diverted via Tawera Rd.
The “deep extinction” of the fumarole involved injecting large amounts of cold water into the bore to cool the geothermal activity and, once done, the fumarole could be filled and the road reopened.
“Well drilling is being organized to plug the well,” the municipality said.
“While the fumarole activity has stopped, steam can still be seen in the area as the surrounding soil takes some time to cool down.”
Matthew Martin/Stuff
A “deep extinction” of the fumarole involved using cold water to collect the geothermal activity.