The Kawerau geothermal field covers an area of 19 to 35 km2. Fluid temperatures exceed 310C. Drilling began at the end of 1952, using experience gained at the Wairakei geothermal field. A significant area of the field to the south and east lying within the resistivity boundary is virtually unexplored. Production is currently limited to an area of about a square km located just north of the mill