Mining in New Zealand - New Frontiers

New Frontiers

Carbon Capture and Storage (CCS) is attracting funding in the billions of dollars as part of global efforts to address greenhouse gas emissions. CCS may well have a vital role to play in the portfolio of technologies to be deployed. The New Zealand Government is a partner with the Australian Government in the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) for research to support commercial-scale CCS. However, in the New Zealand context, University of Canterbury researchers authored a 2009 paper on CCS published in the peer-reviewed journal Energy Policy. The paper considered the permanence of CO₂ storage was uncertain and that CCS was unlikely to significantly reduce carbon emissions. The paper concluded that further investment in CCS was seriously questionable as a policy.

Coal Seam Gas (CSG) is a form of natural gas occurring naturally in deep coal seams that could potentially add to New Zealand’s gas supply. Solid Energy New Zealand has been trialling CSG extraction at the Waikato coal fields, for use in electricity generation.

Deep-sea metallic mineral deposits in the Kermadec volcanic arc are attracting research into how they are formed and how they influence the surrounding undersea biodiversity. Mineral-rich fluids coming out of seafloor hot springs contact cold sea water and precipitate out high-grade ore deposits containing gold, copper, lead, zinc, iron, manganese and other metals. In one sense, these are renewable resources because they are constantly being formed. Discovering these deposits is one matter; mining them in an economic and environmentally appropriate way is another. Extraction of these resources is viewed as a long-term prospect. A proposal for the protection of part of the Kermadec volcanoes is being developed by the Pew Environmental Group.

Geothermal energy is experiencing a renaissance in New Zealand. This renewable source of energy could contribute to 20% of New Zealand’s electricity needs after the next decade. Current research led by the GNS Science and the University of Auckland is tipped to enable cheaper geothermal energy, and identify new systems in the Central North Island for development.

Ironsands offshore of New Zealand from Northland south to Whanganui, and off the South Island’s West Coast is estimated to hold some billions of tonnes of titanomagnetite resource. Titanium and vanadium are the main by-products. The resource is in the stage of being prospected and explored, and assessed for its economic potential.

Low-temperature geothermal energy can be used potentially for space heating, hot pools, heat pumps in the home, heating greenhouses and aquaculture. The heat may be sourced from hot spring systems, disused petroleum wells, heated waters in flooded underground coal and mineral mines, heat in underground aquifers, and heat in rocks. Research in this field in New Zealand is led by GNS Science.

Methane hydrates (fire ice) are a crystalline form of methane trapped in water, occurring in deep-water continental shelf sediments in many parts of the world, including New Zealand. This resource may furnish a future source of natural gas. Work is underway in New Zealand to determine economically viable deposits, and technologies for safe extraction. In New Zealand, methane hydrates are found in shallower waters than elsewhere in the world.

Underground coal gasification (UCG) is a way of accessing energy from coal deposits that lie too deep underground or are too dangerous to be mined or are otherwise uneconomic. Air, oxygen or steam is injected at high temperatures, to burn the coal underground. Separate wells are drilled to capture the resulting “coal gas” which is in essence a form of natural gas. When combined with CCS, this offers a low-emissions route to generating electricity from coal.