Sustainability in Tailings Management
Updated: Feb 23, 2021
On the 6th October 2020, Lynas Rare Earths released to the Australian Stock Exchange their 2020 Sustainability Report highlighting the benefits of the AMC program the Phibion team is undertaking at their Mt Weld operations.
This is an excerpt from this report …
Mt Weld Tailings deposition and consolidation
Rare Earths production generates tailings at Mt Weld, composed of the gangue minerals and water from the mining and floatation stages. Part of the water is recycled, and tailings may be a future source of Rare Earths. In 2019, Lynas completed the Mt Weld Tailings Dam Questionnaire, in response to the Investor Mining & Tailings Safety Initiative. You can view the responses on our website at https://www.lynascorp.com/sustainability/residue-tailings-management.
Tailings generated from the process plant are discharged into Tailings Storage Facilities (TSFs). Our Mt Weld operation is using Accelerated Mechanical Consolidation (AMC) technology to manage tailings and improve consolidation. Lynas has partnered with Australian technology company Phibion, who provide a customised MudMaster® tuned to the specific properties of the Mt Weld operation and supporting low-ground pressure bulldozers for final dewatering and landscaping.
In FY20, there was a reduction in total tailings volume stored at Mt Weld, despite increased tailings deposition from operations. This was achieved due to increased stored density of tailings through the utilization of AMC technology.
Since the implementation of AMC at the Mt Weld operations, Lynas has seen significant improvements including:
A 50% reduction in the tailings volume requiring storage (for the same tailings mass);
An increase in final tailings density from 0.7 t/m3 (dry) to over 1.4 t/m3 (dry);
Development of significant in-situ tailings strength to beyond 30kPa, which ensures stable landforms and supports future rehabilitation activities.
These improvements have delayed the requirement for additional storage capacity in the near future. Although tailings volumes generated over the life of mine will increase as milled ore tonnes increase, we are well positioned to manage tailings in current and future facilities, reducing our overall disturbance footprint.
Phibion is proud to partner with Lynas to improve tailings performance, reduce their environmental footprint and create an enduring and stable landform for eventual rehabilitation.