Introduction
This 2022-23 Annual Environmental Report (AER) has been submitted by Rosslyn Hill Mining Pty Ltd (RHM) for the Paroo Station Minesite (the Project) to the Department of Mines, Industry Regulation and Safety (DMIRS). The AER has been lodged to comply with mining tenements M53/502 (condition 18 version 3), M53/503 (condition 20, version 3), M53/504 (condition 19, version 3) and M53/1002 (condition 19, version 1), miscellaneous leases L53/106 (condition 19, version 3), L53/106 (condition 28, version 3) and L53/149 (condition 28, version 2) requirements, which state:
“The Lessee submitting to the Executive Director, Environment Division, DMP, a brief annual report outlining the project operations, minesite environmental management and rehabilitation work undertaken in the previous 12 months and the proposed operations, environmental management plans and rehabilitation programs for the next 12 months. This report is to be submitted each year in: March.”
This AER covers the period from the 1 March 2022 to the 28 February 2023 and is referred to as ‘the reporting period’ throughout this submission. The Project has been in care and maintenance since the 15 February 2015.
Project Background
RHM has 100% ownership of the Project (DMIRS Project code: J01894, Site code: S0223150) which is located 35 km west of Wiluna on active pastoral leases within the northern Goldfields of Western Australia (Figure 1). RHM is a wholly owned subsidiary of LEADFX Inc (formerly Ivernia Inc) a private base metals company based in Toronto, Canada. The Project’s mining and miscellaneous leases have been illustrated in Figure 2.
The Project mined a shallow lead carbonate resource via open-pit techniques utilising excavators, loaders and trucks to feed a conventional crushing and grinding circuit. A flotation circuit concentrated the ore with the concentrated lead carbonate dried by pressure filtration prior to bagging and shipping within locked sea-containers for overseas markets. The Project achieved first commercial production on the 1 October 2005 but has periodically halted operations due to various market and transportation factors until been placed into voluntary care and maintenance on the 15 February 2015.
The Project's current infrastructure comprises of the following components as depicted in Figure 1.
- Two open pits (Cano and Magellan).
- Run of Mine (RoM) pad.
- Crushing circuit.
- Flotation (existing) and hydrometallurgical (proposed) plant.
- Workshop, laboratory, regent storage and Administration facilities.
- Oxide Waste Rock Landform (WRL).
- Tailings Storage Facility (TSF) and Integrated Waste Landform (proposed).
- Raw water borefield and associated pipeline.
- Water infrastructure (process / raw water ponds and environmental dam).
- Gas/diesel powerstation.
- Accommodation village.
- Landfill and recycling facilities.
- Mine access road off the Goldfields Highway.
- Gravel borrow pit.
- Topsoil stockpiles.
2022-23 Environmental Activities
During the reporting period, RHM undertook environmental monitoring and reporting as per the Project’s 2019 Care and Maintenance Plan (RHM, 2019), Groundwater Licence GWL96342(4) and Prescribed Premises Licence L8493/2010/3 commitments. The results from the various environmental programs have been discussed in section ‘4.2 Monitoring’ with an overview of both the Project’s monitoring, reporting and mining aspects provided below:
Vegetation Disturbance
There was no additional vegetation disturbance during the reporting period. Currently the Project has an approved disturbance footprint of 980 ha within a development envelope of 2,094 ha (Ministerial Statement 1083, OEPA 2018) of which 447.9733 ha has been utilised to-date, with 89.2337 ha (Stage 1 = 74.4919 ha and Stage 2 = 14.7418 ha) rehabilitated and monitored annually utilising Landscape Function Analysis (LFA) transects.
2022 Groundwater Monitoring Summary
To comply with Groundwater Licence GWL96342(4) reporting commitment 3, the Project’s 2022 Groundwater Monitoring Summary (GMS) (RHM, 2023) was lodged with the Department of Water and Environmental Regulation (DWER) (Water unit) on the 23 May 2023. The Project is licenced to abstract up to a total of 2,500,000 kL per calendar year, of which a total of 144,360 kL was abstracted during the DWER reporting period for dust suppression activities and care and maintenance personnel / contractors residing at the Project. A copy of the Project’s 2022 GMS has been provided as Appendix 2 and discussed further in section ‘4.2 Monitoring’.
2022 Landscape Function Analysis
Progressive rehabilitation was undertaken during 2005 and 2014 within sections of the Project’s oxide WRL embankments which have been assessed annually since 2017 utilising LFA. A copy of the Project’s 2022 LFA report has been presented as Appendix 3 and discussed further in sections '3.7 Research and trials' and ‘4.2 Monitoring’.
2021 Mine Closure Plan
The Project submitted an updated Mine Closure Plan (RHM, 2021) on the 19 February 2021, which is currently under DMIRS assessment. The MCP has been discussed in sections '3.6 Rehabilitation and Closure Planning' and '4.1 Environmental and Closure Outcomes'. A copy of the Project's 2019 Care and Maintenance Plan (RHM, 2019) has been provided as Appendix 4.
2022 Annual Environmental Report for Prescribed Premises Licence L8493/2010/3.
The Project continued to undertake high volume dust monitoring, static dust monitoring and ambient ground water monitoring to comply with DWER Prescribed Premises Licence L8493/2010/3 commitments. The results from the 2022 environmental monitoring programmes were reported to DWER via the 2022 Annual Environmental Report (RHM, 2023a) lodged with the Department on the 31 March 2023. A copy of the submitted 2022 AER has been provided as Appendix 5.
Environmental Reporting
The following DMIRS and DWER submissions were lodged throughout the reporting period:
DMIRS
- 2021-22 Mining Rehabilitation Fund information submitted via the Environmental Assessment Regulatory System 2.
- RHM 2022-23 Annual Environmental Report for M53/502, M53/503, M53/504, M53/1002, L53/106, L53/107, L53/108 and L53/149 (this submission).
DWER
- RHM 2022 Groundwater Monitoring Summary – Groundwater Licence GWL177451(4) (RHM, 2023).
- RHM 2022 Annual Environmental Report (RHM, 2023) for Environmental Licence L8493/2010/3. Includes 2022 Annual Audit Compliance Report (RHM, 2023a).
Mining Update
No active mining has been undertaken at the Project since the 17 January 2015. As such, all open pits and the WRL have been appropriately bunded and access roads blocked. Routine monthly inspections of the pit perimeter and where access permits observations for any pit cracking were undertaken by care and maintenance personnel. Pit floors are above the water table and rainfall quickly drains from the pit areas. Acid rock drainage is not considered an issue with the Project’s carbonate ore type. Annual TSF geotechnical reviews have been undertaken during care and maintenance.
2022 TSF Annual Audit
To comply with tenement M53/502 and M53/504 condition 24 the Project commissioned 4DGeotechnics Pty Ltd to undertake the annual TSF audit. A 4DGeotechnics representative completed a site visit between the 23-24 January 2023 to inspect the TSF. The assessment concluded that overall the facility is in reasonable condition and general facility management is adequate (4DG, 2023). A copy of the 2022 TSF audit report has been presented as Appendix 1 in section '3.5 Landform Datasheets'.
Mineral Resource
The Project has an estimated current Mineral Resource of 32 Mt of ore at an average of 4.3% lead (Pb) for an estimated 1,390,000 tonnes of contained lead. The Project has produced over 350,000 t of Pb in concentrate since its first commercial production on the 1 October 2005.
Exploration
There were no exploration activities undertaken on the Project’s tenements during the reporting period.