Earlier investigations show that some geothermal systems of the Taupo Volcanic Zone are sites of precious metal transport and deposition. Gold and silver precipitate in hot springs, in subsurface hydrothermally altered rocks, and in two-phase pipelines associated with production wells, as a result of gas loss due to flashing and adsorption on to As and Sb-rich sulfur phases. The amounts of Au deposited in subsurface rocks may exceed several hundred thousand ounces, but the concentrations appear to be very low grade (<1 ppm Au). High-grade deposits are forming in hot springs, containing >500 ppm Au and >700 ppm Ag, but small metal inventories (<10,000 oz Au) and very high conservation value eliminate these sites as potential resources. Down hole sampling of production wells shows that deep reservoir waters have Au concentrations that range from <0.1 to >20 ppb and Ag concentrations that range from <2 to >2000 ppb. The limited data suggest that at modest concentrations, production wells could produce 0.3 to 3.0 kg Au/year, but that wells in Rotokawa, might produce 19-70 kg Au/year. For modest Ag concentrations, production wells could produce 3-100 kg Ag/year, but wells at Mokai and Rotokawa might produce 680-7500 kg Ag/year. The total amounts of aqueous Au and Ag in reservoirs could be on the order of tens of thousands of ounces Au and hundreds of thousands of ounces Ag, or more. New technologies need to be developed to extract the metals from the flow stream of production wells without interfering with geothermal energy production for continued metal extraction to be feasible. The alternative is to let precious metals accumulate in two-phase pipelines, to be recovered in intervals, when practical for steam field operations and optimal in terms of profitability. (c) 2015 Elsevier Ltd. All rights reserved.