A Review of Aggregates for Land Transport Infrastructure in New Zealand

Aggregates are an important non-renewable resource and the primary raw material for land transport and building infrastructure. New Zealand as a country has an abundant endowment of rock minerals suitable for aggregate for the construction, maintenance, and recycling of public and private infrastructure. However, due to a deficit in infrastructure planning and development for a number of decades, strong population growth in many areas and much of New Zealand’s public infrastructure is coming to the end of its useful and/or economic life — there is an increasing demand for aggregates in many regions of New Zealand. Some regions of New Zealand have difficulties sourcing appropriate materials locally for infrastructure purposes, and there are increasing sensitivities to the extraction of aggregates from communities and iwi/hapu (tribes) who have experienced and seen the effects of poor industry extraction and environmental practices and the lack of monitoring and regulation of consent conditions. Little appropriate data is currently available either nationally or within regions to sustainably plan, manage, use and reuse/recycle aggregates for various public or private infrastructure and therefore to enable the forecasting of future aggregate demand. This paper develops a better understanding of the supply and demand issues both nationally and within regions with the aim of informing a future aggregate strategy to better manage aggregate resources. The paper reviews New Zealand and international literature, reviews aggregate and land use consent data, and evaluates novel methods of EROAD truck transponder data to evaluate aggregate haul distances. Finally, we provide recommendations on how to better manage aggregate supply and demand in New Zealand.