20784 29Metals AR 2022 WEB V1 - Flipbook - Page 39
Waste management
Tailings
We are committed to effective and responsible
management of mining waste, in particular
tailings storage.
Tailings is the term used to describe mine
processing waste and water left behind after
the priority metals have been extracted.
Tailings typically have the consistency of fine sand and
contain waste processing chemicals and residual metals
and minerals.
Tailings dams or tailings storage facilities (‘TSF’) are
engineered structures specifically designed and constructed
to safely store tailings. These TSFs have a finite storage
capacity, with capacity increased through progressive
extensions of the facility wall height (referred to as ‘lifts’).
In some cases, other facilities may be used to store tailings,
such as decommissioned mining open pits, or mined out
underground voids where tailings may be utilised in backfill
in the form of paste or cemented hydraulic fill, as has been
the case at Capricorn Copper where tailings have been
stored in Esperanza Pit.
TSFs are regulated structures and, in Australian
jurisdictions, are subject to comprehensive regulatory
requirements including periodic inspections and
management system audits.
The table below provides details of the TSFs at 29Metals’
operating sites, including the construction method and
current status.
Golden Grove
Site
Capricorn Copper
TSF
Construction method
Detailed studies have commenced at each operation to
evaluate and design new Life of Mine tailings storage facilities.
Following completion of study works and design, 29Metals
will commence the stakeholder engagement and regulatory
approval processes.
Detailed management systems, site specific management plans,
operational manuals and guidelines are in place for our TSFs.
Each TSF is subject to external assurance programs completed
by third party experts at least annually.
29Metals supports the Global Industry Standard on Tailings
Management (‘GISTM’) published by the International Council
on Mining and Metals (‘ICMM’). During the Reporting Period
we completed a gap analysis against to GISTM to identify
opportunities to enhance our management of TSFs.
CASE STUDY
REPROCESSING TAILINGS
29Metals utilises paste fill and cement hydraulic fill as
backfill methods to reclaim and reduce tailings.
During the Reporting Period, 29Metals established a
paste fill plant at Golden Grove to utilise reclaimed dry
tailings from a decommissioned TSF, thereby reducing
the volume of tailings solids stored on surface. We also
completed a scoping study to evaluate the opportunity
to convert the Golden Grove paste plant to a ‘wet’
paste plant – meaning, converting the plant to utilise
tailings directly from the processing plant at Golden
Grove (rather than reclaimed tailings from a TSF).
The results of the scoping study were promising.
Further studies will continue in 2023.
Status
Esperanza Engineered TSF,
TSF
upstream
In use. Lift application
underway to increase
capacity
Esperanza NA. Previously mined
Pit
open cut pit
Tailings deposition ceased
end January 2022
Mammoth Engineered TSF,
upstream
Decommissioned
1980s
TSF 1
Engineered TSF,
upstream
In use
TSF2
Engineered TSF,
upstream
Existing tailings being
re-used as paste backfill
underground
TSF3
Engineered TSF,
upstream
In use. Lift application
underway to increase
capacity
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