Trading under the code HRL, Hot Rock closed at 28.5c yesterday and opened at 29.5c this morning. The company’s initial public offering of 16 million shares was oversubscribed. It has 61.2 million shares and 3 million options.

For now, Hot Rock is focusing on conventional geothermal energy from underground aquifers rather than the hot, dry fractured rock system that relies on engineered reservoirs.

The company plans to begin its exploration program next month with a three-week trial magnetotelluric survey over two of its four Otway Basin, Victoria geothermal exploration licences, according to managing director Mark Elliott.

“This is a relatively standard geophysical technique used to outline high temperature geothermal systems but not previously used in Australia to date,” Elliott said.

Surface sensors will be used to penetrate up to 4km into the Crayfish Subgroup geological formations to help determine where the hottest water and thickest aquifers are.

“We will trial the MT technology along known seismic lines near previously drilled petroleum exploration wells that recorded high geothermal gradients for maximum control on the MT data,” Elliott said.

“If successful, we intend to use this as our main exploration method to help define drill targets.”

Geothermal power is well established in New Zealand, Iceland and parts of the US and the Philippines, but almost unknown in Australia.