“The temperature measured in the target hot granite in this first geothermal exploration well was 82C at 1800m depth,” Green Rock said in a statement on Friday.

“This exceeds the temperature range the company had expected in the granites at such depth prior to drilling the well. Expectations had been that temperatures would reach between 85C and 100C at a depth of 2500m.”

Blanche-1 has recorded the hottest temperatures drilled to date in granite in Australia outside the Cooper Basin, according to Green Rock.

Further temperature measurements will be taken at various time intervals to enable the well to equilibrate with the surrounding hot rocks.

“This may result in a slight increase in the recorded temperatures over time, reinforcing the likelihood that the temperature of the underlying rocks will be sufficient for commercial power generation at the much greater depths planned to be drilled next year,” the company said.

As a result of this drilling, confirmation of hot granite and the observed presence of horizontal fracturing in the granites, Green Rock plans to stop drilling at Blanche-1 on or before reaching a depth of 2000m. Following this the company will carry out geophysical logging of the well, and stress and various chemical analyses of the granites and water.

The next exploratory geothermal well location is in GEL 213, at the site of an existing drill hole, SAP-1, 17km south-west of Blanche-1.

The company plans to re-enter SAP-1, an old mineral exploration drill hole drilled wholly in cover sediments to 1369m, to take temperature measurements and run geophysical logs at the bottom of the hole.

If the temperatures are sufficiently encouraging, Green Rock Energy intends to deepen SAP 1 by drilling into the crystalline basement to confirm temperature gradients and rock properties. Following this, the company plans to drill another geothermal exploration well to confirm the heat anomaly at a location near Blanche-1 and SAP-1.

“The cored geothermal wells being drilled will better define the top of the potential geothermal resource at greater depths,” Green Rock said.

“The information will be used to design two deep geothermal wells to be drilled next year to around 5km depth and establish a pilot circulation cell at depth for trial electricity generation.”

Green Rock Energy is an emerging renewable energy company, focused on becoming a major producer of geothermal energy. The company says its strategic advantage lies in the location of its tenements, adjacent to the Olympic Dam mine, a potential future customer, and close to a national power grid transmission line.