Wollongong Coal, West Dapto
Waterways affected: Avon Reservoir and catchment
Wongawilli Colliery has been operational since 1916, and was placed into ‘care and maintainance mode’ in 2019 following a series of serious safety issues. Wollongong Coal has applied to the Department of Planning, Industry and Environment (DPIE) for a 5 year extension on mining at Wongawilli Colliery, called “MOD2”. It is has not yet been approved by the Department.
1. North West Mains Development proposal
Modification 2 seeks approval to tunnel the North West Mains Development (NWMD).
This tunnelling would extract Bulli Seam coal and rock over until December 2025, over 8km within the Metropolitan Special Areas of the Greater Sydney Water Catchment.
The explicit aim of Wollongong Coal’s MOD2 application is to gain access to a larger area around Avon Reservoir for future mining, as well as reaching an existing ventilation shaft on the northern shore of Avon Reservoir.
As per the Wollongong Coal newsletter, December 2020:
Approval of the modification will enable the NWMD to be completed, and during this period Wollongong Coal propose to seek separate approval to mine within the North West and South West Domain utilising the existing Wongawilli pit top infrastructure with a 30 year mine life
The NWMD would consist of 4 underground roadways, (underground tunnels with interconnects) each 5.5m wide and 3.6m high. They already have permission for approximately 5km of the driveage and the extension applied for is approximately 3 km – this will go beneath Avon Reservoir and Gallaghers Creek.
Wollongong Coal asserts that there will be no future longwall mining at Wongawilli Colliery, however the submission from DPIE Water highlights the inconsistencies in their proposals:
There are several instances of contradiction and uncertainty in the description of the project and the modifications proposed. The most concerning relates to the stated intention by the proponent not to mine using longwall methods (Sections 1.1, 3.2.4 and 4.7.2 of the Mod 2 report) that is contradicted by several statements describing the project and modelling. For example, in the description of mining system stresses (Section 5.4.3) and the report conclusion (Section 10) that states “The proposed mining activities (NW Mains Modification) are to extend approved mining of six long wall panels in the Nebo Area (Nebo Longwalls 1 to 6) for another 5 years, until 31st of December 2025”.
2. Undermining of Avon Reservoir and other waterways
If approved, the NWMD will tunnel 60m beneath Avon Reservoir, as well as undermining Gallaghers Creek.
Wollongong Coal claims there will be no subsidence or environmental impact of this tunnelling as it is “first workings”.
3. Groundwater Losses
The WaterNSW submission to DPIE casts doubts on the groundwater modelling used by Wollongong Coal in their application:
WaterNSW notes that the groundwater model is heavily reliant on data from Dendrobium Mine (Areas 3A and 3B) with 635 monitoring locations compared to only 14 in Wongawilli Mine. It is also noted that the model is a regional groundwater model, instead of a site-specific model. The lack of site-specific groundwater monitoring data means that the groundwater model predictions may not accurately represent the actual outcomes.
The DPIE Water submission similarly raises concerns about the quality of groundwater modelling used in Wollongong Coal’s application:
… the significant shortcomings of the numerical modelling and reporting, some of them fundamental, give DPIE Water significantly diminished confidence in the reliability of the impact predictions. This concern is exacerbated by the sensitive environment hosting the proposal, noting that the mining is planned to go directly underneath Avon Dam and nearby to other mining projects where cumulative impacts are a consideration.
The results of the groundwater model must be reliable with robust uncertainty analysis. They must include an assessment of potential depressurising under the Avon Dam. These predictions must be used in geotechnical modelling and assessment of material stability and potential for cracking under this important water asset.
Even if impact risks are low for this proposal, the proponent states that they intend to use the model for future potential developments. This reinforces the requirement for the model improvements as outline below to occur, to avoid errors and omissions moving forward into future assessments.
Accepting the numerical modelling without an insistence on improvement creates an unacceptable precedent for other project developments.
4. Aboriginal Cultural Heritage destruction
In their submission to DPIE regarding MOD2, Heritage NSW – Aboriginal Cultural Heritage noted:
“The Aboriginal cultural heritage assessment (Biosis 2020a) does not adequately consider the cumulative impact of this mining approval on Aboriginal cultural heritage. There are recorded sites close to the proposed extension including rock shelters with art, grinding grooves and stone artefacts. In addition, there are many recorded Aboriginal cultural heritage sites within the broader mining lease approved under MP09_0161.
The Illawarra Local Aboriginal Land Council raised objections to the assessment process We note objections to the assessment process were raised by the ILALC as reported in the ACHAR (Biosis 2020a, pp.21-22).
The ILALC explained that the proposed works will, in their opinion, cause harm to Aboriginal objects including rock shelters, grinding grooves and art sites (Biosis 2020a). A broader impact will occur to the Aboriginal cultural landscape and associated stories and songlines, as well as water flows and other cultural values”