Review of mine operations plan for private mine 188 White Rock Quarry - request for further information

Following submission of a mine operations plan (MOP) on 23 December 2020, the South Australian Government has assessed the MOP and determined that alterations are required, and additional information necessary to enable further assessment of the proposed future operations of the White Rock Quarry.

Hanson are now required to revise the MOP and re-submit within six months. The revised MOP will then undergo another comprehensive assessment, resulting in either a requirement to make further alterations, or an approval. This process will determine the environmental objectives and criteria that the proposed operations will be regulated against.

A summary of the alterations required to the MOP are outlined below in Table 1: Matters raised - Request for additional information amendment to the White Rock Quarry MOP. The matters raised reflect both Hanson’s obligations under the Mining Act 1971 (Mining Act), and expectations of contemporary quarrying practice in South Australia.

A comprehensive list of the matters requiring alteration is available:

Table 1: Matters raised - Request for additional information amendment to the White Rock Quarry MOP
NumberTopic High level description of matter raised by South Australian government
1. Description of operations (development and rehabilitation) The scope and life of operations are presented inconsistently throughout the MOP, and there is not sufficient information to support statements that an integrated approach to the quarry planning and design process has been undertaken.
2. Progressive rehabilitation and closure strategy Clear objectives or measurement criteria for quarry completion are required. The requirement to provide a quarry closure strategy is deferred to 5 years prior to closure. Development of a post quarry land use plan ensures future options are considered at the appropriate time and in consultation with key stakeholders.
3. Development and rehabilitation Maps and drawings relating to extraction areas, and surface topography are not clearly understood due to the overlying rehabilitation detail. Surface topography displayed in the drawing set appears to be distorted by vegetation and requires review.
4. Third-party property – transmission line The development plan strategy proposes the relocation of a portion of a 275 kV transmission line to access underlying resource. The infrastructure owned by ElectraNet is used to carry electricity to major substations, in this case the Magill and Happy Valley substations.

The MOP review extraction schedule requires review on timing and needs to demonstrate that there is a reasonable prospect of relocating the relevant portion of the Magill – Happy Valley transmission line and that all relevant land use restrictions, and potential impacts have been fully explored.
5. Third-party property – fire/bushfire The quarry is located within a high bushfire risk area close to residential areas of Skye, Teringie, and Norton Summit to the west, north and east (respectively) and conservation areas of Horsnell Gully and Giles Conservation Parks to the south.

The initial impact assessment is presented as ‘medium’. The assessment, control, and management strategies do not adequately address the risk and potential consequence of impacts caused by uncontrolled fire in a high bushfire risk area.
6. Overburden and topsoil The volume of overburden stockpiles must be described. The MOP describes the use of overburden to rehabilitate the quarry. The proponent must demonstrate that there is sufficient overburden (quantity and of quality) to achieve the proposed rehabilitation outcomes and final landform strategy.

The generation and management of overburden material on site is also not discussed in the context of waste. Waste volumes of overburden have not been quantified and no management strategies have been discussed to address surplus material.
7. Geohazards Quarry designs presented are high level, and the MOP does not include any information about geotechnical risks and slope stability analysis, and how they have been considered in the design of the proposed extraction plans and rehabilitation strategies.
8. Blasting Potential direct and indirect impacts caused by blasting activities (flyrock, vibration and overpressure), how impacts will be managed, and blast monitoring frequency and measurement activities, are not adequately described in the MOP.
9. Revegetation The MOP should present detailed revegetation plans for the site, to be clear on what site environmental data may be necessary to inform those plans, and at what stage of the operation that data is required in order to inform the rehabilitation and revegetation plans.
10. Vegetation clearance activities The MOP does not adequately describe how any relevant impacts from vegetation and habitat clearance or disturbance have been determined or will be addressed and is not clear on the footprint of vegetation clearance proposed.
11. Fauna Fauna information provided is based on desktop information sourced from the Protected Matters search tool and the NatureMaps tool. The Protected Matters report states that there are fauna species or species habitat that are ‘known’, ‘likely’ or ‘may occur within the area’.

The fauna aspects of this MOP review should focus on highlighting the risks to significant fauna species (and their habitat) and the impact assessment should be based on the avoid, mitigate and offset hierarchy and providing mitigating actions.
12. Waste The potential impacts from receipt, processing, stockpiling, storage, reprocessing and use or re-use and disposal of waste materials from Hanson plants including returned concrete (inert) and concrete washout waste (alkaline) is not adequately described in the MOP.
13. Aboriginal and non-Aboriginal heritage

Development plans appear to have only considered direct impacts to Pizey’s Knob caused by the extraction footprint and not indirect impacts associated with adjacent operations which should be considered (ie blasting).

The MOP does not address all potential heritage receptors, including the potential for known caves to have heritage value. Some geological features and caves may be protected under legislation including the Heritage Places Act 1993 and Aboriginal Heritage Act 1988. The MOP review does not provide information about consultation with the Traditional Owners to identify the nature and location of any Aboriginal heritage within the proposed development area.

14. Topography and caves Geological landscape heritage features and the presence of any caves should be described in the description of existing environment, for example caves known locally as ‘The Bachelor Pad’ and ‘the Cave’ located within the private mine. This requires an assessment and consideration in the description of existing environment and impact assessment in the MOP which is currently missing.
15. Public safety The impact assessment does not sufficiently describe impact relating to public safety. An assessment of appropriate blast exclusion zones has not been provided in the MOP, consequently it is not clear whether there is an overlap between proposed quarrying activities, blast exclusion zone/s and the areas that are accessed by the public. The MOP also does not address public safety of the rehabilitated landform.
16. Groundwater Further evidence is required to establish relative certainty about the groundwater conditions. DEM notes the commitment to drilling of a monitoring well on the western side of the pit shell throughout Stage 1 to inform and verify the levels to be quarried to post Stage 3. This action is required to be brought forward to assess the activities proposed across Stage 1 to Stage 3a in this MOP.
17. Modes and hours of operation

The MOP describes normal operating hours as follows:

  • Extractive industry operations 5:30 am to 6:00 pm and 6:30 am to 12:00 pm on Saturdays or as required
  • Blasting between 9:00 am and 4:00 pm Monday to Friday, and Saturdays if required
  • Concrete plant and transport operates 24/7

(Note: these hours can change based on sales requirements or to avoid sleeping an explosive shot, upon approval with the Mining Regulator.)

The MOP must clearly state operating hours and what activities will occur within these hours.

18. Plant and transport hours of operation

The operation of the crushing plant is inconsistent with the hours outlined for ‘Extractive industry operations’.

The MOP states ‘the crushing plant starts no earlier than 6:00 am and does not operate past midnight’. Based on the White Rock Quarry Operational Noise Assessment, noise levels from the processing plant are expected to exceed the limits set by the Environment Protection (Noise) Policy 2007 during the night time period of 10:00 pm to 7:00 am, therefore exceeding the noise objective measurement criteria.

19. Noise

The White Rock Quarry Operational Noise Assessment, concludes that the relocation of a processing plant is the most significant contributor to reduced noise emissions from the site. The timing of the relocation/replacement of the plant is not sufficiently clear in the MOP.

It is not clear if haul road movements from the face to the plant were inputs to the modelling in the night-time noise assessment; similarly it is not clear how contributions from construction and rehabilitation works have been included in the impact assessment. The requirement to enclose the crushers and screens for night-time operations is not reflected in the control and management strategies in the MOP.

20. Traffic The impact assessment does not consider the road network beyond the site access gate. Control and management strategies note adherence to the White Rock Quarry Traffic Management Plan and site traffic management policies and procedures, however no plans, policies or procedures have been provided. Control and management strategies note the ongoing inspection and cleaning of the site access road within the private mine to reduce potential dust emissions. Control strategies should also incorporate the length of Horsnells Gully Road to the intersection of Old Summit Road.
21. Plant and equipment References to the location and the type of crushing and screening plant/s on the site varies throughout the MOP. Further clarification is required.
22. Visual amenity The MOP does not clearly articulate how development and rehabilitation plans have been developed to mitigate potential visual amenity impacts, and how the visual representations will be used to evidence that the objective will be achieved.

Further information is required to demonstrate how the quarry development has been designed to progressively mitigate visual amenity impacts, and how quarry development planning reflects earliest achievement of terminal areas, enabling maximum progressive rehabilitation over the life of mine.
23. Light spill

The MOP demonstrates an ongoing commitment for further light spill assessments in the event of a change to lighting configuration.

The following information is provided as a note only: refer to the following Australian Standard for further guidance AS 4282–1997 Control of the obtrusive effects of outdoor lighting.

The processes of undertaking investigations, implementation of corrective actions and reporting requirements should also be reflected in the MOP.

24. Surface water, erosion, and sediment control Current surface water management is not clearly described. The MOP must include a description of sources of sediment, both from the existing operation and proposed expansion and present a water balance calculation for both the existing operation and proposed expansion, considering rainfall, re-use and water draw from dams.
25. Environment improvement program (EIP)

The MOP has not incorporated ongoing obligations of the EIP required by EPA Licence No. 12714 for stormwater management. The management strategies in the EIP should be reflected in the impact assessment to demonstrate the achievement of the objectives. Monitoring requirements of the EIP should be considered in the development of the measurement criteria to demonstrate the effectiveness of the management strategies in achieving the objectives.

The processes of undertaking investigations, implementation of corrective actions and reporting requirements should also be reflected in the MOP.

26. Air quality and dust

It is not clear how mitigation and management measures were derived in the development of management strategies presented in the MOP to manage:

  • extraction activities
  • wind erosion over exposed surfaces and stockpiles
  • haul routes
  • enclosed screens and crushers, fabric filters and water sprays for the proposed new processing plant
  • emissions from concrete batching plant

DEM acknowledges Hanson’s commitment to real-time dust monitoring, and that the dust monitoring program is under development by Hanson in consultation with EPA and DEM. However, the MOP must include:

  • The details of the dust monitoring program, monitoring locations and criteria, must be provided in the resubmission of a MOP.
  • The processes of undertaking investigations, implementation of corrective actions and reporting requirements should also be reflected in the MOP.
  • The management strategies in the dust management plan should be reflected in the impact assessment to demonstrate the achievement of the objectives.

Control and management strategies note adherence to a dust management plan. The plan must be provided. Further information is also required to justify that rehabilitation will mitigate potential impacts associated with dust from exposed areas at closure.

27. Air quality and respirable crystalline silica (RCS)

The MOP must demonstrate that an assessment of the risk of RCS impacts related to quarrying activities has been undertaken and detail an appropriate outcome, management strategies and measurement criteria.

DEM acknowledges the provision of the White Rock Quarry Development – Predicted Respirable Crystalline Silica Emissions Review on 23 February 2021. This document should be incorporated in a resubmitted MOP.

Objectives and criteria

DEM requires all mining operations to perform environmental impact assessments (EIAs) as part of a MOP submission. EIAs must set out strategies to manage the impact of proposed mining operations by setting environmental objectives and measurement criteria. A consolidated list of the matters raised with corresponding requirements for Hanson is available . DEM’s feedback on the MOP as submitted on 23 December 2020 is that it does not currently satisfy the requirements for clearly articulated and achievable objectives and criteria under the Mining Act in relation to:

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