The water quality impact or risk associated with each of these issues is highly case specific and many issues are of little significance at most sites . Where impacts or risks are high there is usually information in mine approval or operational management plans associated with their licensing . However , comprehensive research into the cumulative effects and unlicensed risks of mines to waters in the region is yet to be undertaken .
Only one mine ( Newlands coal in the Rosella sub-catchment ) has a registered discharge directly to waterways reported on the National Pollution Database ( Accessed Sep . 2015 ).
Most active mines emit potentially locally significant quantities of airborne particulate pollutants . Definitive detailed catchment scale research on these matters was not available during preparation of this plan .
Arguably the most significant mining related water quality issues for the region and the GBR are ( GHD , 2012a , b ):
• The risk of gully development and stream bank erosion associated with abandoned mines
• Disruption of linked waterway and aquifer hydrology and quality through entrapment , diversion or use of water
• The development and operation of associated infrastructure
• Storm event driven mobilisation of toxic minerals or chemicals .
Linear infrastructure Linear infrastructure includes all public systems for transport of people or goods . This includes buried or overhead electricity lines , telecommunications , water , gas or fuel pipelines , roads and railways .
The primary risk is of land disturbance and clearing of vegetation which facilitates erosion . Analysis of the area and rate of infrastructure expansion beyond urban areas or water quality changes resulting from major projects also remain as knowledge gaps . However , it was estimated that , every 250km of linear infrastructure works would have an equivalent potential regional sediment loading to all of existing towns . Alternatively , sediment loading from rural linear infrastructure development may be equivalent to that from all other new infrastructure development ( urban expansion ) in the region .
This conclusion based on the assumptions that :
• ground works are occurring along a reserve 20m wide and hence cover an area of 1km 2 every 50km ;
• rural building sites generate similar sediment loads to urban ones ; and
• infrastructure only affects sediment runoff when it is under construction or maintenance .
The water quality risk from the development or maintenance of pipelines , power and communication lines , railways and roads reflects that for urban area development . However , this source of pollutants has not been quantified in the Burdekin Region or the GBR catchments more broadly . The primary risk is of land disturbance and clearing of vegetation which facilitates erosion .
All significant linear infrastructure development projects are regulated and require extensive environmental management plans which include provision avoiding sediment movement or chemical spills which might affect waterways . The potential impacts on water quality associated with modification of the stream and shallow aquifer hydrology are also potentially significant . Development investigations always include detailed hydraulic analysis with respect to the engineering risk and integrity of the infrastructure , but information on the implications of changed water flow paths on the environment is usually less well documented .
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