Environmental and socio-economic costs and benefits of gold mining in New Zealand

Abstract

The excellent mineral potential and diversity of New Zealand gives it a thriving mining industry and a major economic activity, which contributes to its national economic development. Gold has been the most economically important mineral mined in New Zealand from the 1860s to the present day, mostly in the Coromandel, West Coast and Otago regions. This study focused on gold mining in two different regions of New Zealand: hard rock gold mining in the Coromandel Peninsula of the North Island and alluvial gold mining in the West Coast region of the South Island. The emphasis of the study was on active mines in these two regions with respect to prospecting and exploration, mine site development and mining, and related activities including rehabilitation and restoration programmes. The very concept of gold extraction and processing symbolises changes and possible damage to the environment, but at the same time a wide range of socio-economic impacts could contribute to and enhance the socio-economic development of the Coromandel and West Coast regions. A certain environmental price is paid for the socio-economic gains that are made from alluvial and hard rock gold mining in the West Coast and Coromandel regions respectively. The environmental impacts from gold mining in these two regions depend on the type (alluvial or hard rock) and methods (open pit, underground and dredging) of mining. They will also depend on the number and sizes of the mines, the local topography, and the climatic conditions of these regions. Environmental impacts from gold mining in the Coromandel and West Coast regions include competition and disruption of land use, disruption and loss of biodiversity (vegetation, wildlife and aquatic biota) and water, air and land pollution. Other impacts include erosion and sedimentation, noise and ground vibration, hydrology and flooding, visual and aesthetic quality, and landslides and subsidence. Socio-economic impacts include effects on population and settlements, employment, revenue and income, and local and regional economies. Other impacts include effects are archaeological and historic artefacts and sites, recreation and tourism, education, transportation and roading, public conflict protests and conflicts, social organisational change, and social and community services. Environmental/socio-economic benefits are the total benefits resulting from gold mining impacts on the environmental and the socio-economic parameters. Environmental/socio-economic costs on the other hand are the total costs from gold mining impacts on the environmental and socio-economic parameters in the West Coast and Coromandel regions. Quantitative (non-economic) approaches were used to assess the relative importance of environmental and socio-economic impacts of gold mining in the Coromandel and West Coast regions. A qualitative description of impacts was first developed through the use of matrices. The matrix is used to summarise the cause-effect relationships between the identified socio-economic and environmental parameters on one axis (vertical) and the mining and related activities on the other axis (horizontal) in the Coromandel and West Coast regions. Based on the qualitative descriptions, quantitative rankings of impacts for hard rock mining in the Coromandel region and alluvial mining in the West Coast region were developed on a scale of -5 to +5. Negative (-) values signified an adverse impact or cost, and positive (+) values represented a benefit. Rankings of costs and benefits were assigned to both environmental and socio-economic impacts. The spatial and time scale of impacts, and the intensity or risk of impacts, were the major factors taken into account when determining rankings. All the environmental and a few of the socio-economic impacts tend to be localised, while the benefits of employment, revenue and income, and other spending have national and regional as well as localised significance The post-mining activities (restoration and rehabilitation programmes) are intended to minimise the impacts of hard rock and alluvial gold mining and restore the environmental quality of the areas affected by mining in the West Coast and Coromandel regions. Acceptable environmental quality can be achieved depending on the regulatory and legal requirements and the level of commitment or undertaking on the part of the mining companies to carry out restoration and rehabilitation programmes. It also needs a high level of human and financial resources. The consigned rankings of environmental and socio-economic impacts from mining in the Coromandel Peninsula are -26 and +21 respectively with the net impact of -5 (environmental cost). Also the consigned rankings of environmental and socio-economic impacts from mining in the West Coast are -24 and +16 respectively with the net impact of -8 (environmental cost). Gold mining in the Coromandel Peninsula and the West Coast regions all have environmental costs exceeding benefits. Again the total environmental and socio-economic rankings in the West Coast are lower than the corresponding value for the Coromandel Peninsula. There is more information on the impact of mining in the Coromandel Peninsula compared with mining in the West Coast and also the level of environmental awareness among communities in the Coromandel is very high compared with the level of environmental awareness in the West Coast The regulatory bodies generally carry out ineffective environmental monitoring of gold mining activities in the West Coast and the Coromandel Peninsula due to the logistical or financial constraints.