Quarry resource management issues and effects
Quarrying can generate a number of on-site and off-site environmental effects through the blasting, excavation, crushing, screening, stockpiling and transport of aggregate.
The degree and nature of effects caused by quarrying varies according to the type of quarry, the scale of operation, methods used to excavate aggregate, the geology of the area, the receiving environment and the surrounding land uses. The effects of quarries also vary by their nature (rock or sand) and whether they are in short- or long-term use, in continuous use or used irregularly or seasonally.
Quarrying involves the excavation of rock, gravel or sand from the ground (including river beds and beaches). Rock-won aggregate is typically produced through drilling and blasting it from suitable rock deposits, and crushing and screening it to the desired size.
Gravels and sand are normally sourced from river beds (both current and old) and from beaches. Excavation typically involves machinery, without the need for blasting. Crushing of gravel is usually limited to larger gravels while screening is used to separate out smaller sizes for specific uses. Aggregate products requiring further refinement can often involve additional washing, crushing and screening processes.
The uses of rock aggregate range from road preparation and finishing (base and surface) to composite for concrete. Gravel and sand aggregates are similarly used for road and construction products but also have a range of specialty landscaping uses.
Effects are either on site, on neighbouring properties or completely off site, such as the transportation of aggregate. The environmental effects of quarrying primarily include:
- the disturbance of land and vegetation
- the disturbance of river beds or coastal marine areas
- dust
- vibration
- noise
- traffic
- visual effects
- impact on cultural and historic heritage values
- the discharge of contaminants into air, water, land and the coastal marine area.
The effects of quarrying need to be considered when developing appropriate objectives, policies and methods in plans to manage quarrying. Although the effects of quarrying can often be mitigated, they cannot always be avoided.
When establishing parameters around objectives, policies and methods to control the effects of quarrying, it is important to encourage effects to be internalised on site as much as possible. The need to internalise effects also applies to resource consents, where the onus is on applicants to demonstrate they have internalised the effects of their activities as far as is reasonably practicable (see s17 of the RMA and case law on Winstone Aggregates Limited v Papakura District Council (A096/98)). Only where the internalisation of effects cannot be achieved, and protection is warranted, should off-site mitigation or reverse sensitivity measures be considered (refer to the discussion on buffer zones).
Existing use rights should also be considered when identifying effects and developing appropriate methods to manage them. See more on existing uses in the RMA Enforcement Manual.
The positive benefits of quarrying should be considered alongside any adverse effects. Positive effects include:
- the contribution to the economic and social development of an area through the provision of raw materials to maintain and enhance community facilities, services and infrastructure such as water treatment plants, hospitals, schools, airports, new roads, bridges, motorways and new buildings
- the provision of direct and indirect employment opportunities
- diversification of the local economy and support of ancillary services such as engineering, mechanic and construction businesses
- the reduced social and economic costs of having aggregate resources closer to demand
- opportunity for the end use of quarries, for example, recreational or habitat opportunities
- other flow-on regional benefits, including complementary businesses or services.
Gravel extraction resource management issues and effects
Gravel extraction can generate a number of on-site and off-site environmental effects through the excavation of material from riverbeds (or banks of rivers) and the associated, crushing, screening, stockpiling and transport of aggregate.
The degree and nature of effects caused by gravel extraction varies according to the scale of the operation, the methods used to extract the gravel, the surrounding land uses and the ecological and hydrological characteristics of the river environment.
Effects are either on site, on neighbouring properties or completely off site, such as the transportation of aggregate, or where fine sediments area transported downstream in the water column. The environmental effects of gravel extraction primarily include:
- the disturbance of land and vegetation
- the disturbance of river beds or coastal marine areas
- disruption of habitats for birds, freshwater and wildlife species
- dust
- vibration
- noise
- traffic
- visual effects
- impact on cultural and historic heritage values
- the discharge of contaminants into air, water, land and the coastal marine area.
The effects of gravel extraction need to be considered when developing appropriate objectives, policies and methods in District and Regional Plans. Although the effects of gravel extraction can often be mitigated, they cannot always be avoided.
When establishing parameters around objectives, policies and methods to control the effects of gravel extraction, it is important to encourage effects to be internalised on site as much as possible. The need to internalise effects in developing objectives, policies and other methods also applies to resource consents, where the onus is on applicants to demonstrate they have internalised the effects of their activities as far as is reasonably practicable (see s17 of the RMA). Only where the internalisation of effects cannot be achieved, and protection is warranted, should off-site mitigation or reverse sensitivity measures be considered (refer to the discussion on buffer zones).
The positive benefits of gravel extraction should be considered alongside any adverse effects. Positive effects include:
- enhanced flood protection through the removal of excess aggregate from the riverbed
- creation of habitats for birds where gravel extraction is well managed
- the contribution to the economic and social development of an area through the provision of raw materials to maintain and enhance community facilities, services and infrastructure such as water treatment plants, hospitals, schools, airports, new roads, bridges, motorways and new buildings
- the provision of direct and indirect employment opportunities
- diversification of the local economy and support of ancillary services such as engineering, mechanic and construction businesses
- the reduced social and economic costs of having aggregate resources closer to demand
- other flow-on regional benefits, including complementary businesses or services.
