title: Andesite volcanic facies and hydrothermal alteration in the subsurface peripheral to existing Waihi mine workings

authors: Bodger, Billy

subjects: Waihi

abstract: The Waihi vein system is an andesite-hosted epithermal Au-Ag deposit comprising a series of veins located in the southern Hauraki Goldfield, New Zealand. It includes the Martha Mine which is the largest gold producer in the Hauraki Goldfield. Despite a history of over 127 years of prospecting and mining at Waihi, the Favona Au-Ag deposit was recently discovered in blind quartz veins 2 km to the east of Martha Mine. This highlights that there are still new Au-Ag veins to be found and extensions of existing veins to be explored. Little work has been published on the volcanism of the Waipupu Formation andesites, which host the mineralisation. Secondly, the formation of epithermal mineral deposits is accompanied by various chemical reactions which occur between mineralising fluids and host rock, and commonly produce distinct mineralogical and geochemical halos that overprint the volcanic textures and are generally much larger than the ore bodies themselves. The overall aim of this project is, therefore, to reconstruct the volcanic and hydrothermal setting peripheral to the Martha Hill mine. Two northwest-oriented exploration drill holes that are peripheral to the Martha Hill vein system were logged from a volcanological perspective, sampled and analysed by optical mineralogy, TerraSpec, x-ray diffraction on clay separates and x-ray-fluorescence.

Eight new andesite lava facies have been recognised. Six of the facies were identified based on mineral abundances and the presence of quartz phenocrysts. The crystal abundances within these lava facies ranges from 10 to 60% and are dominated by feldspar and mafic minerals. Quartz phenocrysts are minor but prominent features in the rock. These mineral abundances are near synonymous with other active andesite volcanoes and Late Archean examples. The texture of each of the lava facies is dominantly porphyritic, and phenocrysts are mainly plagioclase + ferromagnesian silicates ± quartz. Quartz phenocrysts are commonly resorbed which reflects different levels of magma mixing within the magma chamber before erupting. The other two facies were andesite lava breccias described as either monolithic (containing one clast type) or heterolithic (containing multiple clast types). The monolithic breccia resembles that of an autobreccia, typically associated with the outer parts of a lava flow.

Using alteration mineralogy data (from shortwave infrared spectroscopy and x-ray diffraction on clay separates) and geochemical data (from x-ray fluorescence), a transition from illite to interstratified illite-smectite to smectite was identified heading northwest from the Martha Mine and major mineralised Au-Ag quartz veins. Based on known thermal stabilities for these minerals, a paleoisotherm model was established peripheral to the Martha Hill mine suggesting a “cooling” of the hydrothermal fluid northwest of Martha Mine. Multiple trace elements such as Tl, Bi and Se strongly correlated to the mineralogy, vectoring towards higher temperature mineralisation.

text: Andesite volcanic facies and hydrothermal alteration in the subsurface peripheral to existing Waihi mine workings The Waihi vein system is an andesite-hosted epithermal Au-Ag deposit comprising a series of veins located in the southern Hauraki Goldfield, New Zealand. It includes the Martha Mine which is the largest gold producer in the Hauraki Goldfield. Despite a history of over 127 years of prospecting and mining at Waihi, the Favona Au-Ag deposit was recently discovered in blind quartz veins 2 km to the east of Martha Mine. This highlights that there are still new Au-Ag veins to be found and extensions of existing veins to be explored. Little work has been published on the volcanism of the Waipupu Formation andesites, which host the mineralisation. Secondly, the formation of epithermal mineral deposits is accompanied by various chemical reactions which occur between mineralising fluids and host rock, and commonly produce distinct mineralogical and geochemical halos that overprint the volcanic textures and are generally much larger than the ore bodies themselves. The overall aim of this project is, therefore, to reconstruct the volcanic and hydrothermal setting peripheral to the Martha Hill mine. Two northwest-oriented exploration drill holes that are peripheral to the Martha Hill vein system were logged from a volcanological perspective, sampled and analysed by optical mineralogy, TerraSpec, x-ray diffraction on clay separates and x-ray-fluorescence.

Eight new andesite lava facies have been recognised. Six of the facies were identified based on mineral abundances and the presence of quartz phenocrysts. The crystal abundances within these lava facies ranges from 10 to 60% and are dominated by feldspar and mafic minerals. Quartz phenocrysts are minor but prominent features in the rock. These mineral abundances are near synonymous with other active andesite volcanoes and Late Archean examples. The texture of each of the lava facies is dominantly porphyritic, and phenocrysts are mainly plagioclase + ferromagnesian silicates ± quartz. Quartz phenocrysts are commonly resorbed which reflects different levels of magma mixing within the magma chamber before erupting. The other two facies were andesite lava breccias described as either monolithic (containing one clast type) or heterolithic (containing multiple clast types). The monolithic breccia resembles that of an autobreccia, typically associated with the outer parts of a lava flow.

Using alteration mineralogy data (from shortwave infrared spectroscopy and x-ray diffraction on clay separates) and geochemical data (from x-ray fluorescence), a transition from illite to interstratified illite-smectite to smectite was identified heading northwest from the Martha Mine and major mineralised Au-Ag quartz veins. Based on known thermal stabilities for these minerals, a paleoisotherm model was established peripheral to the Martha Hill mine suggesting a “cooling” of the hydrothermal fluid northwest of Martha Mine. Multiple trace elements such as Tl, Bi and Se strongly correlated to the mineralogy, vectoring towards higher temperature mineralisation.

year: 2015

title: An interview: Making art as a dialogue with materials, moments and motivations

authors: Price, Graham

abstract: Graham Price has worked extensively in primary, secondary and tertiary art education in Otago (1976–1997) and since 2000 in pre-service secondary and primary art education within the University of Waikato arts education team. He has experience in developing art education resources, Waikato professional development programmes, and the development of visual art assessment in primary schools through the National Education Monitoring Project 1995–2008. His research interests include arts integration, the history of art education in New Zealand and how students talk about art. His own artwork spans painting, jewellery and sculptural responses to calligraphy. He actively participates in a cappella choral performance.
In this piece Graham shares his views and his approach to art making.

text: An interview: Making art as a dialogue with materials, moments and motivations Graham Price has worked extensively in primary, secondary and tertiary art education in Otago (1976–1997) and since 2000 in pre-service secondary and primary art education within the University of Waikato arts education team. He has experience in developing art education resources, Waikato professional development programmes, and the development of visual art assessment in primary schools through the National Education Monitoring Project 1995–2008. His research interests include arts integration, the history of art education in New Zealand and how students talk about art. His own artwork spans painting, jewellery and sculptural responses to calligraphy. He actively participates in a cappella choral performance.
In this piece Graham shares his views and his approach to art making.

year: 2017

title: Science-practice roadshow 1: Summary perspectives from centralised entities and agencies

authors: Serrao-Neumann, Silvia

abstract: Flooding is Aotearoa-New Zealand’s most frequent natural hazard, regularly damaging buildings and infrastructure networks, and causing months of disruption to communities and businesses (Hutchings et al. 2019). Also, floods have indirect, cascading, and more intangible impacts (Lawrence, Blackett, and Cradock-Henry 2020), such as the withdrawal of future investment or the emotional stress of recovery. flood risk is predicted to rise quickly due to the combination of climate change and rapid urban intensification (Ministry for the Environment and The Flood Risk Management and River Control Review Steering Group 2008). 

Currently, there is no consistent approach to accurately determine flood risk on a national scale, nor how this may be changing as the climate warms. Instead, flooding risk assessments are done for individual catchments or locations, with the goal of managing and mitigating on the local scale. Local and regional governments vary widely in their capability and capacity to undertake this work (Ford, Berrang-Ford, and Berrang Ford 2011) and, thus, significant differences in data availability and modelling approaches mean that integration of results to gain a pan-region or nationwide picture has not been possible. 

The ‘Mā te haumaru ō nga puna wai ō Rākaihautū ka ora mo ake tonu: Increasing flood resilience across Aotearoa’ research develop a detailed nationwide model that could inform strategic and co-ordinated nationwide decision-making and regulations to support improved resilience to flood risk across the country. Utilising new methods and advances in computer processing and automation, the programme is developing a dynamic risk modelling framework that will assess flood hazard for every catchment in the country and under differing climate scenarios. The model will account for the risks to both built infrastructure and communities so that a fuller understanding of societal costs and impacts can be established. The model’s utility for supporting decision-making will be investigated using an initial set of scenarios for environmental planning, policy settings and infrastructure investment options. Two overarching themes across all of the research - Mtauranga Mori and Uncertainty – are designed to utilise the diverse knowledge systems available to develop tools that are relevant for communities throughout Aotearoa-New Zealand, and to take into account and communicate more clearly flood risks. 

Improved resilience to flooding across Aotearoa-New Zealand is a key outcome sought by the research programme, however it cannot be achieved by research alone. Instead, knowledge and information developed within the programme must be utilised by practitioners in their work to assist communities to plan for, manage, mitigate and avoid flood risks. New knowledge from the programme must be incorporated by practitioners into further tools, policy and decision-making frameworks. This knowledge translation however is not a straight forward process (Dilling and Lemos 2011). Cultural, behavioural and cognitive differences between those who produce and those who utilise knowledge mean that research outputs may not fit the requirements of their intended users, and thus, uptake of research outputs may be compromised. Conversely, strong engagement of knowledge users in the knowledge production process is known to increase the likelihood, and impact, of knowledge implementation. 

Stakeholders are key members of the programme’s research team, representing views across central and local government, engineering, planning consultancies, emergency management, insurance and banking industries, and Te Rūnanga o Wairewa (Banks Peninsula). To broaden the range of stakeholder perspectives, and to facilitate relationships across the programme, we have established a boundary organisation – Te W Te W . Boundary organisations (Guston 2001; Kirchhoff, Esselman, and Brown 2015) are forums that bridge between the two relatively different social worlds of knowledge producers (researchers/scientists) and users (practitioners/policy makers). These forums create and sustain legitimate space and collaboration for knowledge/information to be co-designed, co-produced and co-disseminated (Serrao-Neumann, Di Giulio, and Low Choy 2020). Within our programme, Te W Te W is responsible for organising and facilitating communication and collaboration activities – events (Science-Practice oadshows), communications channels such as an electronic newsletter and website, and learning opportunities. Through this organisation, we are fostering trust, legitimacy and capacity for information use so that our research results will be usable, useful, and used. 

This report summarises the discussion and perspectives shared at the first Science-Practice Roadshow held in October 2021.

text: Science-practice roadshow 1: Summary perspectives from centralised entities and agencies Flooding is Aotearoa-New Zealand’s most frequent natural hazard, regularly damaging buildings and infrastructure networks, and causing months of disruption to communities and businesses (Hutchings et al. 2019). Also, floods have indirect, cascading, and more intangible impacts (Lawrence, Blackett, and Cradock-Henry 2020), such as the withdrawal of future investment or the emotional stress of recovery. flood risk is predicted to rise quickly due to the combination of climate change and rapid urban intensification (Ministry for the Environment and The Flood Risk Management and River Control Review Steering Group 2008). 

Currently, there is no consistent approach to accurately determine flood risk on a national scale, nor how this may be changing as the climate warms. Instead, flooding risk assessments are done for individual catchments or locations, with the goal of managing and mitigating on the local scale. Local and regional governments vary widely in their capability and capacity to undertake this work (Ford, Berrang-Ford, and Berrang Ford 2011) and, thus, significant differences in data availability and modelling approaches mean that integration of results to gain a pan-region or nationwide picture has not been possible. 

The ‘Mā te haumaru ō nga puna wai ō Rākaihautū ka ora mo ake tonu: Increasing flood resilience across Aotearoa’ research develop a detailed nationwide model that could inform strategic and co-ordinated nationwide decision-making and regulations to support improved resilience to flood risk across the country. Utilising new methods and advances in computer processing and automation, the programme is developing a dynamic risk modelling framework that will assess flood hazard for every catchment in the country and under differing climate scenarios. The model will account for the risks to both built infrastructure and communities so that a fuller understanding of societal costs and impacts can be established. The model’s utility for supporting decision-making will be investigated using an initial set of scenarios for environmental planning, policy settings and infrastructure investment options. Two overarching themes across all of the research - Mtauranga Mori and Uncertainty – are designed to utilise the diverse knowledge systems available to develop tools that are relevant for communities throughout Aotearoa-New Zealand, and to take into account and communicate more clearly flood risks. 

Improved resilience to flooding across Aotearoa-New Zealand is a key outcome sought by the research programme, however it cannot be achieved by research alone. Instead, knowledge and information developed within the programme must be utilised by practitioners in their work to assist communities to plan for, manage, mitigate and avoid flood risks. New knowledge from the programme must be incorporated by practitioners into further tools, policy and decision-making frameworks. This knowledge translation however is not a straight forward process (Dilling and Lemos 2011). Cultural, behavioural and cognitive differences between those who produce and those who utilise knowledge mean that research outputs may not fit the requirements of their intended users, and thus, uptake of research outputs may be compromised. Conversely, strong engagement of knowledge users in the knowledge production process is known to increase the likelihood, and impact, of knowledge implementation. 

Stakeholders are key members of the programme’s research team, representing views across central and local government, engineering, planning consultancies, emergency management, insurance and banking industries, and Te Rūnanga o Wairewa (Banks Peninsula). To broaden the range of stakeholder perspectives, and to facilitate relationships across the programme, we have established a boundary organisation – Te W Te W . Boundary organisations (Guston 2001; Kirchhoff, Esselman, and Brown 2015) are forums that bridge between the two relatively different social worlds of knowledge producers (researchers/scientists) and users (practitioners/policy makers). These forums create and sustain legitimate space and collaboration for knowledge/information to be co-designed, co-produced and co-disseminated (Serrao-Neumann, Di Giulio, and Low Choy 2020). Within our programme, Te W Te W is responsible for organising and facilitating communication and collaboration activities – events (Science-Practice oadshows), communications channels such as an electronic newsletter and website, and learning opportunities. Through this organisation, we are fostering trust, legitimacy and capacity for information use so that our research results will be usable, useful, and used. 

This report summarises the discussion and perspectives shared at the first Science-Practice Roadshow held in October 2021.

year: 2022-02