Dams & Tailings Management

The design, construction, operation and closure of all TSFs in Western Australian mines must comply with the Mines Safety and Inspection Act 1994 (MSIA 1994), Mines Safety and Inspection Regulations 1995 (MSIR 1995) and Mining Act 1978 as well as the department’s codes and guidelines. This is completed in conjunction with the requirements, approval and licensing from the Department of Water and Environmental Regulation (DWER).

The Department of Mines, Industry Regulation and Safety (DMIRS) requires mining companies to undertake rigorous design processes that match the designated risk/consequence profile for each TSF regardless of construction method. These design processes are set out in DMIRS' code of practice and guidelines.

These detailed processes consider all the factors that can potentially impact on the stability of TSFs and the extent of unwanted outcomes. Examples of some of the factors assessed in the complex design processes include:

• The location and general layout of the site;
• Size and height of the TSF;
• Nature of materials to be stored in the TSF;
• Tailings deposition method;
• The liquefaction potential of the tailings;
• Assessment of the effects of TSF failures (dam break studies) under a combination of worst-case scenarios, and provision of control and management requirements;
• Materials used for construction and foundations;
• Climate, drainage, etc; and
• Construction methods.

TSFs also require detailed and regular inspection and auditing, including the preparation and implementation of a site-specific Operating Manual which sets out the safe and environmentally acceptable operating procedures, monitoring and reporting requirements, trigger levels and actions to be taken to rectify any impending deficiencies.  Findings of audits must be submitted to DMIRS and DWER with compliance verified by their officers through site inspections and document review processes.

The Regis Approach to Tailings Management 

Regis adopts a risk management approach to tailings management that follows the life cycle of a TSF, including (but not limited to): 

• site selection;
• design;
• construction;
• operation;
• emergency planning;
• decommissioning planning and rehabilitation; and
• decommissioning monitoring and maintenance.

To achieve the targeted management outcomes, and in line with the regulatory requirements and industry practice as outlined in the DMIRS “Code of Practice: Tailings storage facilities in Western Australia” and ANCOLD “Guidelines on Tailings Dams – Planning, Design, Construction, Operation and Closure”, detailed prescriptive methodologies and specific control measures are included in Regis:

• project management plans;
• mining proposals;
• design reports;
• project management plans prior to construction;
• construction reports;
• operating manual;
• emergency response plans;
• periodic environmental reports;
• periodic audit reports;
• decommissioning plans; and 
• closure plans

This also includes the requirement for the use of independent TSF consultant engineers for the design and annual inspection of all Regis built TSFs as well as requirements for the provision of information, instruction, training and supervision to ensure the integrity of the TSFs and occupational safety and health of affected personnel.

Further and consistent with the principals of continuous improvement, the Regis approach to tailings management will continue to be modified by considering and incorporating relevant learnings from tailings incidents in other parts of the world along with any other relevant new information that will help in delivering further improvement.

Due to the remoteness of the current operations, no communities are affected by Regis’ current TSF footprints. However, Regis is considering a new mine project that would require a TSF being constructed near the local community. Regis does already and will continue to engage and communicate directly with that community prior to and as part of any approvals process being undertaken. 

Tailings Disclosure Inventory (as at September 2020)

Notes:
1. The hazard rating is used in design to establish design criteria. It considers amongst other things, the worst-case scenarios of release of tailings and water at maximum design level during maximum probable rain and flood events to ensure the suitability of the design to ensure no adverse impact on safety or on the environment.