3.1 Groundwater monitoring EA requirements As per EA Condition W7, groundwater quality must be monitored at MB2, MB3, MB5-S/D, MB7D, MB8D, MB9 and MB14 on a monthly basis. EA Condition W8 lists the required parameters and analytes that must be monitored, including: – Physicochemical indicators: pH Electrical conductivity @ 25°C (EC) Total dissolved solids @180°C (TDS) – Toxicants (in the dissolved fraction): Cyanide (HCN as CN) Aluminium (Al) Arsenic (As) Cadmium (Cd) Chromium (Cr) Cobalt (Co) Copper (Cu) Lead (Pb) Manganese (Mn) Nickel (Ni) Selenium (Se) Zinc (Zn) 3.2 Monitoring and sampling methodology Groundwater monitoring was undertaken by Heritage Minerals on a monthly basis as required under Condition W7 of the EA. Field monitoring and sampling sheets have not been provided to GHD, however, it is understood that the following details have been recorded by Heritage Minerals: – Date and time of sampling – Depth to groundwater from top of casing – Sampling methodology – Groundwater quality observations It is GHD’s understanding that sampling was preferentially completed using a low flow (submersible) pump after three purging three bore volumes. A recommended sampling framework is presented in Appendix G as a reference for future groundwater monitoring. GHD understands that samples were collected in laboratory supplied sample bottles, with filtration for metals completed by the laboratory with sample volume sourced from an unpreserved sample bottle. GHD’s understanding was that samples were kept in ice filled eskies and re-iced before dispatch to the laboratory. Samples were documented on appropriate Chain of Custody (CoC) documentation and transported to Australian Laboratory Services (ALS), a National Association of Testing Authorities (NATA) accredited laboratory.
Samples were analysed for the following analytical suite: – Physicochemical parameters: pH, EC and TDS – Dissolved metals: Al, As, Cd, Cr, Co, Cu, Pb, Mn, Ni, Se, Zn – Total cyanide
GHD | Heritage Minerals Pty Ltd | 12638246 | Groundwater Quality Review 2024 14
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