Anglesea Mine Rehabilitation and Closure

Mine Rehabilitation and Closure

Throughout our 46 years of mine operations in Anglesea, we were driven by a strong commitment to employee and community health and safety, and protection of the environment. This commitment continues today and guides our rehabilitation and closure activities which are set to ensure a safe, stable and sustainable landform, enabling community use.

We are consulting Traditional Owners, the local community and government regulators in developing our rehabilitation strategy, with our work strongly aligning with the guiding principles developed with the community and key stakeholders in 2016.

The final Anglesea Mine Rehabilitation and Closure Plan will be approved by the Victorian Government’s Earth Resources Regulation. Key referring agencies include the Department of Energy, Environment and Climate Action, EPA Victoria and Southern Rural Water. Corangamite Catchment Management Authority and Barwon Water are also identified as key stakeholders.

Mine Work Plan

The approved Anglesea Mine Work Plan was developed to outline the strategy for the continuing operation of the Anglesea Coal Mine by Alcoa of Australia to 2061. It contains closure concepts and a defined process for the mine rehabilitation and closure, inclusive of community engagement. We updated this plan and it was endorsed by the Victorian Government in 2011.

Draft Mine Rehabilitation and Closure Plan

Concepts within the Mine Work Plan required revision, due to permanent closure of the power station and mine in August 2015, 45 years earlier than expected.

Rehabilitation and future landform of the area disturbed by mining is detailed in the Draft Mine Rehabilitation and Closure Plan. The document was prepared by Alcoa following engagement with the community and key stakeholders and submitted for approval to Earth Resources Regulation in 2017. Features include a large water body, extensive rehabilitated areas and proposed areas including access for future alternative land uses.

There are three key pieces of work in the Draft Mine Rehabilitation and Closure Plan:

  1. Major earthworks program;
  2. Vegetation strategy; and
  3. Waterbody filling strategy.
Read the Draft Mine Rehabilitation and Closure Plan

Rehabilitation Progress

Rehabilitation commenced in 2018 and since then we have achieved several major milestones including:

  • Completing the major earthworks program which involved moving more than 7 million tonnes of material to provide safe and stable slope profiles within the former mine;
  • Installing nine surface water drains to safely convey surface rain water flows from the crest of the mine to the future water body, and 16 groundwater monitoring wells in and around the periphery of the mine to monitor groundwater quality and levels during development of the future water body;
  • Relocating a 1.2 kilometre section of Coalmine Road and management transferred to the Surf Coast Shire Council;
  • Continued establishment of native heathy woodland topsoil on the north and west mine walls (13 hectares);
  • Hydroseeding and continued establishment of native grasslands on the south mine wall (over 50 hectares); and
  • Implementing an ongoing monitoring and maintenance program in the mine for earthworks and revegetation including stability, monitoring, erosion repairs and extensive weed management.

Vegetation Strategy

A Vegetation Strategy was prepared with the support of technical consultants Ecology Australia and Ag-Challenge, who have had a long association with the mine’s rehabilitation activities. As outlined in the draft MRCP 2017, the Vegetation Strategy has three key objectives:

  1. Minimise impact on the Anglesea Heath;
  2. Preserve historical rehabilitation; and
  3. Infill historical rehabilitation with native species.

The following two methods have been used across approximately 77 hectares:

Carried out across 2018 and 2019, the topsoil subsoil revegetation amounts to approximately 24 hectares. The purpose of the technique, and as per past practice at Anglesea, is to establish native heathy woodlands. The areas completed with this technique since 2018 include the north and west walls of the mine, the old mine haul road and infill historical rehabilitation areas such as the former fire services dam.

We know from experience that revegetation using this technique takes time, however we also know this will return great diversity to these areas. To date all areas are establishing well, and we continue to see good results in the native heath vegetation species regenerated from the topsoil.

Maintenance and monitoring of these areas is underway including inspections, species monitoring and a weeding program to remove invasive species.

Over 50 hectares of native grasslands is now establishing well on the steeper southern mine slopes.

The primary grassland species, selected after an almost two-year onsite trial, includes five native Wallaby Grasses (Rytidosperma spp.). These are widespread in the Victorian landscape with their respective distributions extending to the Anglesea area.

The specific species include:

  1. Brown-back Wallaby-grass (Rytidosperma duttonianum);
  2. Copper-awned Wallaby-grass (Rytidosperma fulvum);
  3. Common Wallaby-grass (Rytidosperma caesptiosum);
  4. Bristly Wallaby-grass (Rytidosperma setaceum); and
  5. Slender Wallaby-grass (Rytidosperma racemosum).

The grasses were hydroseeded into an engineered topsoil consisting of an organically enriched course gravelly sand overlying a sandy clay that has been treated with calcium sulphate (gypsum).

Our primary goal is to establish the grasslands. In the first 12 months we achieved approximately 56 per cent ground cover, with 80 per cent coverage our target over the next two years.

We also envisage potentially ‘softening’ the grasslands slopes with shrubs and trees at an appropriate time. No timeframe has been set for this, particularly as we expect heath species will naturally recruit and establish into the grasslands, which is visibly occurring already.

Our maintenance and monitoring program is in full swing and includes regular inspections, an ongoing invasive weed program and erosion control activities undertaken where necessary.

Mine Water Filling Strategy

Filling the mine pit with water is a key enabler to finalise the Anglesea Mine Rehabilitation and Closure Plan. To further investigate using groundwater to support the long-term filling strategy, we completed a groundwater pumping test in 2021.

Read more about the Mine Water Filling Strategy

Mine Technical Studies

Three major technical assessment components have been undertaken to inform all water aspects, any land potential risks and a revegetation assessment. These are undertaken by experienced consultants and independently peer reviewed where appropriate.

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