title: “The best flood I ever had”: Contingent resilience and the (relative) success of adaptive technologies

authors: Connelly, Angela

subjects: Flood risk management

abstract: The practical operationalisation of resilience within cities is strongly linked to technology, such as better construction materials or redesigning urban form. Institutional and private sector actors often focus on issues relating to the technological innovation journey, such as ‘pathways’ to implementation or ‘barriers’ to market uptake, rather than whether adaptive technologies are the most appropriate resilience solution. These discourses frame urban resilience from the perspective of an innovation journey where technologies are perceived to succeed if there is high uptake. However, given the multi-perspective and multi-scale nature of urban resilience, the idea of ‘success’ inevitably has complex spatial, temporal and scalar dimensions. The paper uses the case of property level flood resilience (PFR) technologies in the United Kingdom to introduce the notion of ‘contingent resilience’ as a means to understand the trade-offs that are part of assessing and evaluating climate resilient technologies. We reveal that there are fundamental contradictions in what is deemed as a ‘success’ depending on who is framing the problem, when the judgement is made, or where the scale of analysis lies. Above all, the paper highlights the importance of illuminating the struggles that do not just define success, but that spatially and temporally redistribute climate resilience in a hidden manner.

text: “The best flood I ever had”: Contingent resilience and the (relative) success of adaptive technologies The practical operationalisation of resilience within cities is strongly linked to technology, such as better construction materials or redesigning urban form. Institutional and private sector actors often focus on issues relating to the technological innovation journey, such as ‘pathways’ to implementation or ‘barriers’ to market uptake, rather than whether adaptive technologies are the most appropriate resilience solution. These discourses frame urban resilience from the perspective of an innovation journey where technologies are perceived to succeed if there is high uptake. However, given the multi-perspective and multi-scale nature of urban resilience, the idea of ‘success’ inevitably has complex spatial, temporal and scalar dimensions. The paper uses the case of property level flood resilience (PFR) technologies in the United Kingdom to introduce the notion of ‘contingent resilience’ as a means to understand the trade-offs that are part of assessing and evaluating climate resilient technologies. We reveal that there are fundamental contradictions in what is deemed as a ‘success’ depending on who is framing the problem, when the judgement is made, or where the scale of analysis lies. Above all, the paper highlights the importance of illuminating the struggles that do not just define success, but that spatially and temporally redistribute climate resilience in a hidden manner.

year: 2020

title: The silica issue in the limestone resource at McDonald's Oparure Lime Quarry

authors: Hansen, Orla

subjects: limestone

abstract: McDonald's Oparure Lime Quarry extracts limestone from the latest Oligocene to earliest Miocene aged Otorohanga Limestone formation of the Te Kuiti Group.  The quarry produces a range of limestone grades that are utilised by various industries, including the iron and steel, agricultural, and roading construction industries.  One of the most important aspects of production is quality control which is driven by quality restrictions on the chemical composition of the limestones imposed by the industrial end users.  In steel manufacture, silica is highly undesirable as it has detrimental effects on downstream processes such as the ability of calcium oxide to remove impurities from the steel and its abrasiveness inside pipes transporting lime into the steel making vessel.  A guideline of lt;1.7% silica content in the lime is required.  

McDonald's Lime Ltd and major shareholders Holcim New Zealand Ltd are aware that silica levels vary across the Oparure limestone resource, and so hold some concerns about their ability to maintain quality guidelines on their limestone products.  Consequently, it is relevant that knowledge be gained about the nature, distribution, and origin of silica-rich zones within the limestone resource so as to allow for greater certainty in quarry planning and operations.  

The main aims of this study were to determine the chemical stratigraphy of the limestone units in the quarry so as to assess primary sources of silica in the intact limestone (host limestone); to use field methods to measure the nature and distribution of a variety of discontinuity features which separate the intact rock blocks within the limestone rock mass; to identify sources of secondary silica-rich materials and their characteristics; and to determine the overall distribution of silica within the limestone resource.  Additionally, a ground penetrating radar (GPR) trial was undertaken to establish whether this geophysical technique is successful in detecting subsurface caves that may trap silica-rich materials.  

The host limestone or intact rock mass of the quarry units contains variable amounts of calcium carbonate, as follows: Caprock (av. 89.5%), Upper Steel (av. 98.2%), Aglime (av. 94.5%), High Grade (av. 97.2%), Lower Steel (av. 97.3%), and Sub-economic (av. 95%).  The remaining non-carbonate component largely resides in silica-bearing minerals such as clay minerals, quartz, feldspar, and glauconite, but also in authigenic minerals such as pyrite and gypsum.    

In McDonald's Oparure Lime Quarry six main discontinuity types are identified, all of which are associated with silica-rich materials.  The six discontinuity types are: (1) discrete seams; (2) diffuse seams; (3) subhorizontal stylolites; (4) subvertical stylolites; (5) joints; and (6) caves and other karst features.  Types (1), (2), and (3) have formed as a result of burial of the carbonate-rich sediments during which pressure dissolution has preferentially dissolved skeletal fragments, leaving behind and concentrating insoluble residue (siliceous material).  These are primary sources of silica.  Types (4) and (5) are produced as a result of tectonic activity, including deformation and uplift.  Subvertical stylolites formed by pressure dissolution associated with tectonic stresses during uplift of the limestones, and their contained silica also derives from a primary source inside the limestone strata.  Type (6) discontinuities are produced by dissolution by fresh water of the subaerially exposed limestone.  Joints, caves, and other karst features trap silica-rich materials sourced mainly from overlying overburden lithologies, including the Quaternary Kauroa Ash and the early Miocene Mahoenui Group mudstone; these are secondary sources of silica.  A distinctive leathery clay mineral called palygorskite occurs commonly as a chemical precipitate in both joints and caves as an infill.  A final source of silica identified that is not a discontinuity material, but is operation induced, involves the accumulation of blast and road dust coating rock surfaces, here referred to as surface accumulations.

The overburden units and discontinuity materials show a range of chemical compositions and some, such as cave infills, comprise greater than 60% SiO2.  The main siliceous minerals within overburden units and discontinuity materials are clays (smectite, palygorskite, gibbsite, vermiculite, halloysite, illite), quartz (and minor cristobalite), feldspar (oligoclase), and glauconite.  Carbonate minerals including mainly calcite and minor dolomite.  

GPR successfully detected cave structures to an effective penetration of about 10 m, but cave infills cannot be quantified using this method.

The knowledge gained in this study about the distribution, location, quantities, and nature of the silica materials in the limestone units, closely related to the different discontinuity types identified, has the potential to assist in determining appropriate processing techniques to minimise the silica issue at the Oparure Quarry.

text: The silica issue in the limestone resource at McDonald's Oparure Lime Quarry McDonald's Oparure Lime Quarry extracts limestone from the latest Oligocene to earliest Miocene aged Otorohanga Limestone formation of the Te Kuiti Group.  The quarry produces a range of limestone grades that are utilised by various industries, including the iron and steel, agricultural, and roading construction industries.  One of the most important aspects of production is quality control which is driven by quality restrictions on the chemical composition of the limestones imposed by the industrial end users.  In steel manufacture, silica is highly undesirable as it has detrimental effects on downstream processes such as the ability of calcium oxide to remove impurities from the steel and its abrasiveness inside pipes transporting lime into the steel making vessel.  A guideline of lt;1.7% silica content in the lime is required.  

McDonald's Lime Ltd and major shareholders Holcim New Zealand Ltd are aware that silica levels vary across the Oparure limestone resource, and so hold some concerns about their ability to maintain quality guidelines on their limestone products.  Consequently, it is relevant that knowledge be gained about the nature, distribution, and origin of silica-rich zones within the limestone resource so as to allow for greater certainty in quarry planning and operations.  

The main aims of this study were to determine the chemical stratigraphy of the limestone units in the quarry so as to assess primary sources of silica in the intact limestone (host limestone); to use field methods to measure the nature and distribution of a variety of discontinuity features which separate the intact rock blocks within the limestone rock mass; to identify sources of secondary silica-rich materials and their characteristics; and to determine the overall distribution of silica within the limestone resource.  Additionally, a ground penetrating radar (GPR) trial was undertaken to establish whether this geophysical technique is successful in detecting subsurface caves that may trap silica-rich materials.  

The host limestone or intact rock mass of the quarry units contains variable amounts of calcium carbonate, as follows: Caprock (av. 89.5%), Upper Steel (av. 98.2%), Aglime (av. 94.5%), High Grade (av. 97.2%), Lower Steel (av. 97.3%), and Sub-economic (av. 95%).  The remaining non-carbonate component largely resides in silica-bearing minerals such as clay minerals, quartz, feldspar, and glauconite, but also in authigenic minerals such as pyrite and gypsum.    

In McDonald's Oparure Lime Quarry six main discontinuity types are identified, all of which are associated with silica-rich materials.  The six discontinuity types are: (1) discrete seams; (2) diffuse seams; (3) subhorizontal stylolites; (4) subvertical stylolites; (5) joints; and (6) caves and other karst features.  Types (1), (2), and (3) have formed as a result of burial of the carbonate-rich sediments during which pressure dissolution has preferentially dissolved skeletal fragments, leaving behind and concentrating insoluble residue (siliceous material).  These are primary sources of silica.  Types (4) and (5) are produced as a result of tectonic activity, including deformation and uplift.  Subvertical stylolites formed by pressure dissolution associated with tectonic stresses during uplift of the limestones, and their contained silica also derives from a primary source inside the limestone strata.  Type (6) discontinuities are produced by dissolution by fresh water of the subaerially exposed limestone.  Joints, caves, and other karst features trap silica-rich materials sourced mainly from overlying overburden lithologies, including the Quaternary Kauroa Ash and the early Miocene Mahoenui Group mudstone; these are secondary sources of silica.  A distinctive leathery clay mineral called palygorskite occurs commonly as a chemical precipitate in both joints and caves as an infill.  A final source of silica identified that is not a discontinuity material, but is operation induced, involves the accumulation of blast and road dust coating rock surfaces, here referred to as surface accumulations.

The overburden units and discontinuity materials show a range of chemical compositions and some, such as cave infills, comprise greater than 60% SiO2.  The main siliceous minerals within overburden units and discontinuity materials are clays (smectite, palygorskite, gibbsite, vermiculite, halloysite, illite), quartz (and minor cristobalite), feldspar (oligoclase), and glauconite.  Carbonate minerals including mainly calcite and minor dolomite.  

GPR successfully detected cave structures to an effective penetration of about 10 m, but cave infills cannot be quantified using this method.

The knowledge gained in this study about the distribution, location, quantities, and nature of the silica materials in the limestone units, closely related to the different discontinuity types identified, has the potential to assist in determining appropriate processing techniques to minimise the silica issue at the Oparure Quarry.

year: 2008

title: Kia whakatōmuri te haere whakamua: ‘I walk backwards into the future with my eyes fixed on my past’

authors: Rameka, Lesley Kay

subjects: Māori

abstract: This whakataukī or ‘proverb’ speaks to Māori perspectives of time, where the past, the present and the future are viewed as intertwined, and life as a continuous cosmic process. Within this continuous cosmic movement, time has no restrictions – it is both past and present. The past is central to and shapes both present and future identity. From this perspective, the individual carries their past into the future. The strength of carrying one’s past into the future is that ancestors are ever present, existing both within the spiritual realm and in the physical, alongside the living as well as within the living. This article explores Māori perspectives of the past and the models and inspiration they offer. In this way, it provides a critique of the practices in early childhood education, highlighting the importance of cultural concepts and practices, and discusses implications for both teaching and academic practice.

text: Kia whakatōmuri te haere whakamua: ‘I walk backwards into the future with my eyes fixed on my past’ This whakataukī or ‘proverb’ speaks to Māori perspectives of time, where the past, the present and the future are viewed as intertwined, and life as a continuous cosmic process. Within this continuous cosmic movement, time has no restrictions – it is both past and present. The past is central to and shapes both present and future identity. From this perspective, the individual carries their past into the future. The strength of carrying one’s past into the future is that ancestors are ever present, existing both within the spiritual realm and in the physical, alongside the living as well as within the living. This article explores Māori perspectives of the past and the models and inspiration they offer. In this way, it provides a critique of the practices in early childhood education, highlighting the importance of cultural concepts and practices, and discusses implications for both teaching and academic practice.

year: 2017