THERMAL BORES

Press, Volume XCIII, Issue 28002, 23 June 1956, Page 4

THERMAL BORES

Control Regulations Being Drafted SEQUEL TO MISHAP AT KAWERAU “The Press” Special Service WELLINGTON, June 22. Regulations to govern the sinking of bores in thermal areas are being drafted, and are expected to be introduced shortly. It is likely the regulations will cover bores put down in Rotorua for thermal heating purposes as well as for producing power. Although regulations prescribing safety precautions for the drilling of geothermal bores have been under consideration for some time, it is understood that the mishap to American drilling equipment and the complete loss of control over a bore at Kawerau have caused urgency to oe given to their promulgation. The Geothermal Energy Act. 1953, gives wide powers for the making of regulations controlling the drilling of geothermal bores. It is expected they will prescribe as minimum requirements the precautions and preparations made by engineers of the Ministry of Works at their wells at Wairakei and Kawerau.

In their investigations, the engineers have not lost control of any bores since their drilling programme started in earnest in 1952, and their projects have always been governed by well-planned safety devices. They have been prerequisites to the start of drilling into thermal country. At all the Wairakei and Kawerau bores, heavy concrete drilling pits have been built, and in most cases the ground has been consolidated at the surface by pumping in concrete grouting before drilling. The engineers have found it necessary also to grout heavy steel casing into the ground near the surface.