Part V Works Approval, Licences and Registrations)
7.6 Emissions to Land and Water
Hydrocarbons and hazardous wastes
Hazardous materials will not be stored or used on site during the construction or operation of the Inert Premise and/or the Putrescible Premise.
During construction, fuels and other hydrocarbons (i.e. lubricants) will be managed at both the Inert Premise and the Putrescible Premise as per the management procedures outlined within the CEMP.
These management measures will include requirements for hydrocarbon storage, disposal, spill clean- up and maintenance practices to minimise the risk of releases.
Priority control measures which will be implemented throughout the construction and operation phases include:
• Hydrocarbons will be stored within secondary containment (i.e. bunding) which meets the requirements of Australian Standard (AS) 1940:2017
Page 37 of 78
• Spill kits will be located close by to refuelling areas, mobile refuelling facilities, workshops and storage areas
• If a hydrocarbon release occurs it will be controlled, contained and removed using spill kit materials or other absorbent material. Contaminated soils will be collected and disposed to an appropriately licenced waste facility
• Hydrocarbon and chemical spills are reported internally as an environmental incident and larger spills with the potential to cause contamination are reported externally to DWER
• Mobile equipment used for the construction will be operated and serviced in line with the manufacturer’s specification
• Servicing and refuelling of plant, machinery and vehicles will only be undertaken within designated servicing and refuelling facilities.
Windblown Wastes
Covalent will implement management measures to prevent waste being blown outside of either the Inert Premise and/or the Putrescible Premise during operations.
Windblow waste will be minimised via the following measures:
• Both the Inert Premise and the Putrescible Premise will be fully fenced (refer to Section 2.3.2 and Section 3.3.2)
• Inert and Putrescible waste will be covered on a monthly basis
• Lidded bins will be used throughout the Earl Grey Lithium Project DE to minimise windblown wastes (prior to waste being disposed to the premises)
• Waste will be covered when transported to the Putrescible Premise
• Waste material from the Project accommodation village will generally be in bags, reducing risk of windblow waste from trucks when waste is transported to the Inert Premise and/or the
Putrescible Premise
• Site induction will provide all site-based personnel with information and education on permitted waste disposal and recycling
• Complaints relating to waste will be recorded and investigated as per the Covalent Incident Management Procedure.
In addition, any waste that is blown outside of the Inert Premise and/or the Putrescible Premise will be returned to the landfill at least once every month in accordance with the Regulation of the Environmental Protection (Rural Landfill) Regulations 2002.
Fires
The operation of the Inert Premise and the Putrescible Premise presents a fire risk as some materials disposed could be combustible under certain conditions or if contacted with particular materials.
Covalent will ensure a firebreak of at least 3 m is constructed around the boundary of the Inert Premise and the Putrescible Premise. This firebreak will be maintained for the life of the Inert Premise and the Putrescible Premise.
Covalent will dispose of electrical offcuts (including those containing copper and lithium batteries) to the Inert Premise rather than the Putrescible Premise, to minimise the risk of fire within the
Putrescible Premise which contains flammable materials such as wood.
Page 38 of 78 Stormwater and Leachate
During the operation of the Inert Premise and Putrescible Premise, there is potential for stormwater runoff to enter trenches/cells and promote the formation of leachate (discussed in Section 6.2.5).
Covalent commissioned GHD (2021) to undertake a Stormwater Modelling Assessment, to determine potential runoff volumes and make recommendations for appropriate stormwater controls. The full report is provided as Appendix 8. The assessment outlined the following appropriate stormwater management infrastructure for the Inert and the Putrescible Premise:
• Upslope undisturbed runoff will be diverted around the Inert and the Putrescible Premise via clean water diversion bunds:
o The clean water diversion bund height will be a minimum 0.5 m and constructed directly on the embankment of the landfill trenches when operational, to prevent surface water runoff from entering the trench as well as providing a safety buffer for site personnel and machinery
o The clean water diversion bunds will remain in place until the landfill cap is constructed and shallow-rooted vegetation is stabilised
• To minimise surface water runoff entering the Inert and the Putrescible Premise from the access ramps, a smaller ‘speed bump’ style diversion bund will be constructed at the top of the ramp to allow trucks to easily access the trench for waste disposal.
In addition, as the proposed Putrescible Premise is situated within an existing Borrow Pit, a
stormwater detention basin will be constructed in the northern portion of the pit (northeast of the landfill trenches) to capture and divert surface water runoff away from the trenches:
• Surface water runoff collected within the detention basin will either evaporate from the basin or be pumped and utilised as dust suppression or other on-site activities
• The detention basin will be constructed with side slopes of 3% to a depth of ~0.7 m below ground level
• The detention basin has a water holding capacity to the embankment of 445 m3
• A minimum freeboard of 0.3 m will be maintained at all times within the basin to prevent the basin from overflowing.
The following control measures will be undertaken to ensure that stormwater infrastructure is appropriately managed and operates efficiently and effectively:
• Regular inspections of the alignment, grade and integrity of clean water diversion bunds
• Regularly desilting of the detention basin to maintain an appropriate water holding capacity.
The operation of the both the Inert Premise and Putrescible Premise has the potential to impact to soils (through leachate) if water is allowed to collect in the trench/ cells in contact with waste.
However, given the depth to groundwater, and nature of wastes to be disposed to the Inert Premise (see Section 2.3.4) and Putrescible Premise (see Section 3.3.4), organic loading (leachate) is
considered unlikely.
Plastic or clay liners are not proposed for the Inert Premise or Putrescible Premise to ensure water does not pool within the landfill, which can result in a higher acidity of leachate percolating through soils. However, the potential for water to collect in the trench/cell following an intense rainfall event has been considered in the design of the Inert Premise and Putrescible Premise with gentle gradients and sumps included to collect excess water and keep it separate from waste while infiltration occurs
Page 39 of 78 (refer to Section 2.3.2, Section 3.3.2, and Appendix 8). As an additional measure, Covalent will ensure bunds are appropriately placed around the Inert Premise and Putrescible Premise (as per
recommendations from GHD 2021), in order to divert surface water flows around the premises.
Covalent will also ensure that capping of both the Putrescible and Inert Premises will bring the final landform to above ground-level. This will prevent depressions in the cap as the waste breaks down and prevent water pooling.
Waste disposed of at the Inert Premise and/or the Putrescible Premise will also be covered and compacted to a level that will reduce the ability for water to percolate through the landfill.
Soil Erosion and Sedimentation
Disturbance of soil during the operation and construction of the Inert Premise and Putrescible Premise has the potential to cause soil erosion.
Activities likely to increase erosion risk include:
• Stripping soil within the premise footprint – no management proposed as stripped surfaces will only be exposed for a very short time (less than 1 week prior to excavation)
• Stockpiling soil – requires ongoing monitoring and implementation of corrective actions as required with materials will be used to cover waste across the life of the premises
Covering waste with earth fill – requires ongoing monitoring and implementation of corrective actions as required.
Construction control measures proposed to mitigate mobilisation of sediments from the premise and/or instability of the trench/ cell walls include:
• Topsoil (from within the premise footprint) will be stripped to a depth of approximately 200 mm and used to rehabilitate outer surfaces at closure of the premises (and as required during operation of the premises if erosion of cover fill is observed)
• Minimise timeframe between stripping topsoil and commencing excavation of the trench/ cells (1 week maximum)
• Minimise timeframe between commencing excavations and completing constructing the premise (2 weeks maximum), whereby the final constructed landform will have battered slopes (as per design drawings presented in Appendix 7) to minimise the risk of soil erosion
• Implement stormwater controls in accordance with the GHD (2021) Stormwater Modelling Assessment, including appropriate placement of bunds at the perimeter of the Inert Premise and Putrescible Premise to divert surface water flows around the premises.
Operational control measures proposed to mitigate mobilisation of sediments from the premise and/or instability of the trench/ cell walls include:
• Monitor soil stockpiles and cleared surfaces adjacent to the premises for evidence of soil erosion and sediment transport
• If evidence of soil erosion and sediment transport is observed, Covalent will implement sediment control (such as earth bunds, sumps, rock armouring or revegetation) as appropriate, to control or prevent soil erosion which could compromise the integrity of the trench/ cell walls.
Following closure of the landfill trenches, the following control measures shall be established to maintain the integrity of the cap and minimise cap erosion:
Page 40 of 78
• Maintenance of the cap vegetation to reduce erosion and sediment mobilisation, and assist batter stability
• Maintenance of the cap thickness to ensure a sufficient barrier between the waste and the environment
• Regular inspections of the cap to ensure a sufficient grade is maintained on the cap to facilitate stormwater flow off the landfill footprint and reduce the potential for ponding.
Page 41 of 78
8 Risk Assessment
This section presents an assessment of potential environmental risks for the emissions, discharges and wastes identified in Section 6, that may occur during the construction and operation of the Inert Premise and Putrescible Premise. The risk assessment has been undertaken in accordance with the DWER Guidance Statement: Risk Assessments (released by the then named Department of
Environmental Regulation in 2017) shown in Table 8-1.
Table 8-1: Risk Rating Matrix
Consequences
Insignificant Minor Moderate Major Severe
Likelihood Rare Low Low Medium High
Unlikely Low Low Medium High High
Possible Low Low Medium High Extreme
Likely Low Medium High Extreme Extreme
Almost certain
Low Medium High Extreme Extreme
Risk = consequence vs likelihood
The following criteria (DWER 2017) are used to determine the consequence and likelihood of a risk event occurring Table 8-2 and Table 8-3.
Table 8-2: Consequence matrix
Consequence Consequence descriptor
Environment Health
Severe • On-site impacts: catastrophic
• Off-site impacts (local scale): high level
• Off-site impacts (wider scale): mid level
• Mid to long term or permanent impact to an area of high conservation value or special significance
• Loss of life
• Adverse health effects: high level or ongoing medical treatment
• Local scale impacts: permanent loss of amenity
Major • On-site impacts: high level
• Off-site impacts (local scale): mid level
• Off-site impacts (wider scale): low level
• Short term impact to an area of high conservation value or special significance
• Adverse health effects: mid level or frequent medical treatment
• Local scale impacts: high level impact to amenity
Page 42 of 78
Consequence Consequence descriptor
Environment Health
Moderate • On-site impacts: mid level
• Off-site impacts local scale: low level
• Off-site impacts wider scale:
minimal
• Adverse health effects: low level or occasional medical treatment
• Local scale impacts: mid level impact to amenity
Minor • On-site impacts: low level
• Off-site impacts (local scale):
minimal
• Off-site impacts (wider scale): not detectable
• Local scale impacts: low level impact to amenity
Slight • On-site impact: minimal
• Specific Consequence Criteria (for environment) met
• Local scale: minimal impact to amenity
• Specific Consequence Criteria (for public health) criteria met
Table 8-3: Likelihood matrix
Likelihood Likelihood description
Almost certain The risk event is expected to occur in most circumstances.
Likely The risk event will probably occur in most circumstances.
Possible The risk event could occur at some time.
Unlikely The risk event will probably not occur in most circumstances.
Rare The risk event may only occur in exceptional circumstances.
The potential emissions, sources, pathways and receptors that have been identified for the
construction and operation of the Inert Premise and the Putrescible Premise are outlined in Table 8-4.
This table also identifies the potential impacts, proposed controls and associated risk ratings.
A detailed risk assessment is undertaken for any activity which has been identified as having a
‘medium’ risk rating or higher. A detailed risk rating assessment includes:
• A description of the potential emissions, sources, pathways and receptors
• Any controls that have been identified for the risk event
• An assessment of the consequence and likelihood
• Risk analysis rating and residual risk rating.
Page 43 of 78
Table 8-4: Risk analysis
Source/Activities Potential Emissions Pathway Potential Receptor Potential Impacts Risk analysis (prior to management control measures)
Proposed management control measures
Residual risk rating (after management control measures)
Consequence Likelihood Risk matrix rating
Consequence Likelihood Risk matrix rating
Construction of the Inert Premise and the Putrescible Premise
NOx, SO2, CO2, PM10, VOCs
Dust
Air: Release of NOx, SO2, CO2, PM10, VOCs from operating machinery/vehicles.
Air: Windborne particulate (dust) emissions generated by activities including machinery/ vehicle movements and earthworks to strip topsoil, stockpile topsoil and excavate the trenches/cells.
Earl Grey Lithium Project
accommodation village (located more than 2 km from the premises)
Health and amenity of personnel resident and working on-site: dust and gaseous emissions are not expected to impact the health and amenity of residents at the accommodation village given the separation distance (>2km), short construction timeframe (1-2 weeks) and management controls implemented (Section 7.2.1).
Insignificant Likely Low Dust management control measures:
• Use of water carts as needed to wet down dust generating surfaces such as roads, earthworks areas
• Topsoil stripping/
stockpiling and excavation activities will be restricted during high winds if dust cannot be adequately controlled
• Use of weather forecasting to predict extreme weather conditions likely to result in increased dust emissions so that Covalent can minimise the impact through application of additional dust controls or modified activities
• Use of defined haul routes for machinery/
vehicles travelling on unsealed surfaces or roads
• Reduced vehicle speed limits in areas of unconsolidated soil
• Any complaints relating to dust emissions will be recorded and
investigated as per the Covalent Incident
Insignificant Possible Low
Vegetation (mostly regrowth) and fauna
Impacts of dust on vegetation and fauna are expected to be negligible given the short construction timeframe and
implementation of management controls as presented in Section 7.2.1.
Minor Possible Low Minor Rare Low
Page 44 of 78 Source/Activities Potential Emissions Pathway Potential Receptor Potential Impacts Risk analysis (prior to management
control measures)
Proposed management control measures
Residual risk rating (after management control measures)
Consequence Likelihood Risk matrix rating
Consequence Likelihood Risk matrix rating
Management Procedure
• Proposed management controls included in the CEMP.
Air emission management control measures:
• Vehicles not left idling when in use
• Machinery and vehicles are regularly services and operated/
maintained in accordance with the manufacturer’s specifications
• Maintain a complaint register, investigate, and review
management methods, as required
• Proposed management controls included in the CEMP.
The proposed management controls are expected to effectively mitigate the identified risks (Section 7.2.1).
Noise Air: Noise emissions generated from operation of machinery/ vehicles
Earl Grey Lithium Project
accommodation village (located more than 2 km from the premises)
Noise emissions are not expected to impact the amenity of the surrounding environment for identified receptors given the separation distance (>2km) and management controls implemented (Section 7.2.1).
Insignificant Rare Low Noise emission management controls:
• Machinery/ vehicles used for the construction will be operated and serviced in line with the manufacturer’s specifications
• Maximum sound power levels are
Insignificant Rare Low
Fauna occupying habitats in areas
Noise emissions may deter fauna from habitats in proximity of the premises,
Insignificant Rare Low Insignificant Rare Low
Page 45 of 78 Source/Activities Potential Emissions Pathway Potential Receptor Potential Impacts Risk analysis (prior to management
control measures)
Proposed management control measures
Residual risk rating (after management control measures)
Consequence Likelihood Risk matrix rating
Consequence Likelihood Risk matrix rating
proximal to the premises
which has the potential to impact on survivorship of the individual. However, given the short-term and minor nature of noise generating activities which will only occur during daylight hours, impacts to fauna from noise are expected to be negligible (Section 6.2.2)
specified for machinery/ plant (if required)
• Construction will take place during daylight hours, thereby limiting noise emissions during the night
• Complaints relating to noise will be recorded and investigated as per the Covalent Incident Management Procedure
• Proposed management controls included in the CEMP.
The proposed management controls are expected to effectively mitigate the identified risks (Section 7.3.1).
Light Air: Light emissions generated from operation of machinery/ vehicles and temporary lighting (if required for safe construction of the premise)
Earl Grey Lithium Project
accommodation village (located more than 2 km from the premises)
Given the closest receptor is more than 2 km from the premises, use of lights by plant/ machinery/ vehicles during construction of the facilities (which would only be required early mornings, late afternoons) is not expected to impact amenity of the surrounding
environment for residents of the accommodation village (Section 6.2.4).
Insignificant Rare Low Light emission
management controls:
• Construction will take place during daylight hours (between 7am and 5pm)
• Proposed management controls included in the CEMP
The proposed management controls are expected to effectively mitigate the identified risks (Section 7.5.1).
Insignificant Rare Low
Fauna occupying habitats in areas proximal to the premises
Light emissions can disorient, distract, or deter fauna from habitats in proximity of the premises, which has the potential to impact on survivorship of the individual. However, given construction will only
Insignificant Rare Low Insignificant Rare Low
Page 46 of 78 Source/Activities Potential Emissions Pathway Potential Receptor Potential Impacts Risk analysis (prior to management
control measures)
Proposed management control measures
Residual risk rating (after management control measures)
Consequence Likelihood Risk matrix rating
Consequence Likelihood Risk matrix rating
occur between 7am and 5pm (with a limited need for artificial light early morning and late afternoon), and the short timeframe for construction, impacts to fauna from light are expected to be
negligible (Section 6.2.4).
Hydrocarbons/
hazardous waste
Land: Accidental release (spills/leaks) of hydrocarbons from machinery/ vehicles causing contamination of land
No hazardous waste will be stored or used
The primary receptor will be soil.
Impacts to groundwater are not expected given groundwater is estimated to occur from
approximately 58 m bgl (Section 5.5.2).
Impacts to surface water are not expected given numerous earth bunds have been constructed across the mine site which have effectively diverted surface drainage around most of the Earl Grey Lithium Project DE (Section 5.5.3)
Given the current disturbed nature of the site, the primary risk of accidental hydrocarbon release would be in sterilisation of future mineral resources. Given the small quantity of hydrocarbons required to power
machinery/equipment during construction, and the proposed controls
presented in Section 7.6.1 impacts are expected to be negligible.
Minor Possible Low Hydrocarbon management controls:
• Hydrocarbons will be stored within secondary containment (i.e.
bunding) which meets the requirements of Australian Standard (AS) 1940:2017
• Spill kits will be located close by to refuelling areas, mobile refuelling facilities, workshops and storage areas
• If a hydrocarbon release occurs it will be controlled, contained and removed using spill kit materials or other absorbent material.
Contaminated soils will be collected and disposed to an appropriately licenced waste facility
• Hydrocarbon and chemical spills are reported internally as an environmental incident and larger spills with the
Insignificant Unlikely Low