Legal rights to minerals in geothermal fluids

Abstract

This report is a discussion document which forms part of research into the commercial potential in New Zealand for the extraction of minerals from geothermal fluids. It undertakes a legal analysis of rights to the minerals and materials that may be obtained from such fluids. Geothermal fluids are extracted for the purposes of electricity generation and process heat, predominantly in the Taupo Volcanic Zone, but also in other parts of the country. The mineralization of the fluid varies from system to system, and, although the concentrations of minerals are not high, in some instances the quantities of fluid extracted are large. Silica is found in all high temperature geothermal fluid. It has some commercial value, depending on its character and grade, but its main significance is that it causes a build-up of scale in equipment and can make it more difficult to re-inject fluid into a subsurface system after use. Other materials that may be commercially viable for extraction are salts of boron and lithium. That the costs of extraction from the ground have already been met suggests that the commercial viability of producing minerals from the flow of fluid in a power station or other facility is greater than it would be otherwise. Where silica must be removed to facilitate re-injection or more efficient electricity generation, another step in an extraction process may also have been paid for. It might therefore be possible that geothermal minerals operations can produce by-products and income flows in association with the use of geothermal resources for energy purposes.