Amendment Notice 2 Licence Number L8412/2010/2 Licence Holder Regis Resources Limited ACN 009 174 761 File Number: 2012/006893 Premises Moolart Well Mining Tenements M38/354, M38/498, M38/499, M38/500 and M38/589 LAVERTON WA 6440 Date of Amendment 27/05/2019 Amendment The Chief Executive Officer (CEO) of the Department of Water and Environmental Regulation (DWER) has amended the above Licence in accordance with section 59 of the Environmental Protection Act 1986 (EP Act) as set out in this Amendment Notice. This Amendment Notice constitutes written notice of the amendment in accordance with section 59B(9) of the EP Act. Tim Gentle Manager – Resource Industries an officer delegated under section 20 of the Environmental Protection Act 1986 (WA) Licence: L8412/2010/2 IR-T08 Amendment Notice (Major) template v2.0 (July 2017) 1 Definitions and interpretation Definitions In this Amendment Notice, the terms in Table 1 have the meanings defined. Table 1: Definitions Term Definition ACN Australian Company Number AER Annual Environment Report Amendment Notice refers to this document Category/ categories of Prescribed Premises as set out in Schedule 1 Categories/ Cat. of the EP Regulations CEO means Chief Executive Officer. CEO for the purposes of notification means: Director General Department Administering the Environmental Protection Act 1986 Locked Bag 10 Joondalup DC WA 6919 [email protected] Delegated Officer an officer under section 20 of the EP Act Department means the department established under section 35 of the Public Sector Management Act 1994 and designated as responsible for the administration of Part V, Division 3 of the EP Act. DWER Department of Water and Environmental Regulation EPA Environmental Protection Authority EP Act Environmental Protection Act 1986 (WA) EP Regulations Environmental Protection Regulations 1987 (WA) Existing Licence The Licence issued under Part V, Division 3 of the EP Act and in force prior to the commencement of and during this Review Licence Holder / Regis Resources Limited Licensee Licence: L8412/2010/2 IR-T08 Amendment Notice (Major) template v2.0 (July 2017) 2 Noise Regulations Environmental Protection (Noise) Regulations 1997 (WA) Prescribed has the same meaning given to that term under the EP Act. Premises Premises refers to the premises to which this Decision Report applies, as specified at the front of this Decision Report. Risk Event as described in Guidance Statement: Risk Assessment Licence: L8412/2010/2 IR-T08 Amendment Notice (Major) template v2.0 (July 2017) 3 Amendment Notice This amendment is made pursuant to section 59 of the Environmental Protection Act 1986 (EP Act) to amend the Licence issued under the EP Act for a prescribed premises as set out below. This notice of amendment is given under section 59B(9) of the EP Act. This notice is limited only to an amendment for Category 5. No changes to the aspects of the original Licence relating to Categories 73, 85 and 89 have been requested by the Licence Holder. The following guidance statements have informed the decision made on this amendment Guidance Statement: Regulatory Principles (July 2015) Guidance Statement: Setting Conditions (October 2015) Guidance Statement: Decision Making (February 2017) Guidance Statement: Risk Assessment (February 2017) Amendment description On 21 December 2018, the Regis Resources Limited (Licence Holder) submitted an application to amend the Moolart Well Gold Project licence L8412/2010/2. The Licence Holder applied for the following changes: Approval for the construction and operation of a new in-pit Tailings Storage Facility (TSF) at the Stirling pit on tenement M38/499 and M38/500; and Installation of six monitoring bores (constructed to a depth of 80m) around Stirling pit and the addition of these monitoring locations on the licence; Bores to be added: RRLMWMB045, RRLMWMB046, RRLMWMB047, RRLMWMB048, RRLMWMB049, RRLMWMB050. To date tailings have been deposited into an above ground TSF at the Moolart Gold Project. The development of the Stirling in-pit TSF will provide continued tailings storage for Moolart Well when the existing TSF has reached capacity. Stirling TSF will contain processed tailings from various open pits at Moolart Well, Gloster, Dogbiter/Coopers, Anchor and the as yet approved Petra pits. Stirling pit has an approximate rim area of 31 ha, and a length south-north of approximately 1km. The pit has a maximum depth of approximately 75m. It is expected that approximately 10 million tonnes (Mt) of tailings will be deposited into the in-pit TSF over 3-4 years. The supporting documentation has been prepared by consultants CMW Geoscience Pty Ltd and includes the full engineering design report. The supporting document stated that the design has been done in accordance with the Department of Mines and Petroleum (2013), ‘Code of practice: tailings storage facilities in Western Australia’. The location of the new Stirling TSF and the 6 new monitoring bores is shown in Figure 1 below. Licence: L8412/2010/2 IR-T08 Amendment Notice (Major) template v2.0 (July 2017) 4 Figure1: Location of proposed Stirling TSF and six new monitoring bores. Licence: L8412/2010/2 IR-T08 Amendment Notice (Major) template v2.0 (July 2017) 5 Operation of the Stirling TSF The Licence Holder’s application states that an operations manual for the TSF outlining the operating procedures, inspection criteria, monitoring, requirements and log sheets for the facility will be prepared for the Stirling TSF prior to commissioning. The operation of the Stirling TSF will be as follows; Stage 1 (Start-up): Tailings in the form of slurry will be discharged sub-aerially via two single point discharges from the northern pit wall; Tailings deposition is to be carried out such that the supernatant pond is around the southern area of the pit; and There is an opportunity for mine waste, if available, to be used to backfill the pods in the south western and south eastern area of the TSF to reduce ponding at the base of the pit in isolated pockets. Stage 2 (Year 1): Tailings will continue to be discharged sub-aerially via two single point discharges from the northern pit wall until the tailings level reaches nominally RL 500 m; Surface water will be removed from the TSF by a decant pump located on the pit ramp at the southern end of the pit. The decant pump will be moved up the ramp as tailings and water levels rise. Stage 3 (Year 2): Tailings discharge will be undertaken from the northern boundary with additional deposition from the south west corner of the pit. This will facilitate the migration of the supernatant pond towards the central east location in the pit. As the supernatant pond migrates towards the central east location of the TSF, the decant pump will be stationed on a floating pontoon or similar. Stage 4 (Year 3): The tailings discharge point will be moved along both the northern and southern boundary to ensure the even build-up of a tailings beach sloping gradually towards the floating pontoon decant at the central east location of the SPTSF. An embankment will be constructed on the northern boundary with compacted mine waste to raise the pit level at the northern end of the pit (between RL526 and RL 530m). As outlined above an embankment raise is proposed in the third year of operation of the Stirling TSF. The estimated tailings storage areas, volumes and storage capacity for the TSF are summarised in Table 2 below. Table 2: Estimated Tailings Storage volumes (CMW Geosciences Pty Ltd, 2019). Licence: L8412/2010/2 IR-T08 Amendment Notice (Major) template v2.0 (July 2017) 6 Tailings is planned for discharge alternatively from each end of the pit to optimise beaching length and decant drainage as well as for maximum evaporation drying. Water recovery system Surface water will initially be removed from the TSF by a decant pump deployed from the pit ramp at the southern end of the pit. Return water will be pumped directly to the process plant for reuse. The decant pump will be moved up the ramp as tailings and water levels rise. As the supernatant pond migrates towards the central east location of the TSF, the decant pump will be stationed on a floating pontoon or similar. A ramp access for pump maintenance will need to be constructed in Year 3 on the central east wall of the pit (CMW Geosciences Pty Ltd, 2019). Other approvals The Licence Holder has provided the following information relating to other approvals as outlined in Table 3. Table 2: Relevant approvals Legislation Number Approval RIWI Act 1914 1. GWL169314 (2) Moolart 1. Approval to extract 5,000,000kL Well for mine dewatering and dust suppression 2. GWL175982(1) Rosemont 2. Approval to extract 3. GWL182924 (1) Gloster 1,300,000kL for mineral ore processing and other mining purposes and dewatering for mining purposes and dust suppression for mining purposes 3. Approval to extract 1098750kL of water for dewatering for mining purposes and dust suppression for mining purposes. Mining Act 1978 Mining Proposal Mining Lease 38/354, 38/498. 38/499, 38/500, 38/589 Mining proposal for the Stirling TSF has been approved after the licence holder commissioned an independent 3rd part review of the geotechnical design of the ‘saddles’ pillars that will be left between the Stirling in-pit facility and the two neighboring operations, Landcaster and Beaufort pits. The independent review concluded that the geotechnical design is appropriate and so based on this DMIRS has approved the proposal. Amendment history Table 4 provides the amendment history for L8412/2010/2. Licence: L8412/2010/2 IR-T08 Amendment Notice (Major) template v2.0 (July 2017) 7 Table 3: Licence amendments Instrument Issued Amendment L8412/2010/2 31/03/2016 Amendment to correct the limit for the treated wastewater discharged to the irrigation area.