Name
Lady Loretta mine.

Location
North West Minerals Province, in Queensland, Australia.

Mine Owner/s
Glencore.

Brief Description
Lady Loretta is a lead/zinc/silver mine, located 140 km north-north-west of the Mount Isa operations, in Queensland.

Brief History
The deposit was discovered in 1969. Since then, the deposit has been extensively explored by several companies. 

Glencore subsidiary Xstrata Zinc eventually assumed sole ownership of the Lady Loretta mine area in 2011.

Production was suspended in October 2015, owing to poor zinc prices. Glencore decided to resume production in 2018, with the mine having been operated by contract miner Redpath Mining Australia since then.

The mine produced a record 1.696-million tonnes of zinc/lead/silver ore in 2021, exceeding the previous record of 1.549-million tonnes set in 2020.

Primary Metals/Minerals
Zinc, lead and silver.

Secondary Metals/Minerals
None stated.

Geology and Mineralisation
The Lady Loretta lead/zinc/silver deposit is considered a “classic” sediment-hosted base metal deposit exhibiting many of the features documented for similar deposits of the Mount Isa inlier, according to the Australian Institute of Geosciences Journal.

The deposit is localised in a tight north-east plunging syncline, which was modified by later folding and locally offset by reverse faulting. The upper 120 m to 150 m of the ore horizon has been extensively oxidised, and at surface appears as a prominent gossanous ridge that exhibits elevated base metal values.

Mineralisation reportedly occurs on both steeply dipping limbs of the synform, which connects at a thickened keel position at a depth of 500 m from surface. The north and south limits of the deposit are fault-truncated, with the fault movement suggesting uplift and the subsequent erosion of the ore horizon.

In general, the deposit exhibits a pronounced metal zonation from high-lead, zinc-rich mineralisation on the west limb and in the keel, to a low-lead, zinc-rich mineralisation on the east limb, extending along strike to the north.

Resources changes are predominantly associated with mining activity, drilling and improvements in overall modelling and estimation techniques.

Reserves
As at December 31, 2022, Lady Loretta had a total reserve of 4.1-million tonnes grading 9.98% zinc, 2.33% lead and 46 g/t silver.

Resources
As at July 26, 2011, before mine development started, Lady Loretta had a total mineral resource estimated at 13.7-million tonnes grading 17% zinc and 6% lead.

As at December 31, 2022, Lady Loretta had a measured and indicated resource of 5.8-million tonnes grading 11.87% zinc, 2.65% lead and 54 g/t silver.

Type of Mine
Underground.

Mining Method
Underground.

Major Infrastructure/Equipment
Ore is crushed on site before being transported to Mount Isa Mines, where it is blended with ore from George Fisher mine and processed at the zinc/lead concentrator and smelter.

The mine is building a modern engineered waste-rock emplacement facility as part of the mine rehabilitation process.

Prospects
The Queensland Metals newsletter ‘Resourceful’  in February 2022 noted that a detailed closure plan was being finalised. The plan outlined the activities and resources required for progressive rehabilitation, as well as the decommissioning and closure of all components of the mine during operations and post-closure.

In October 2023, Glencore announced that the Lady Loretta zinc mine, would close in the second half of 2025.

At the time, the Queensland Resources Council said Glencore’s decision was unfortunate, but understandable.

Following the post-closure period, the site is proposed to be used for native vegetation habitat and grazing land.

Contact Details
Glencore Australia
Tel +61 2 8247 6300
Email communications@glencore.com.au

Sources
Australian Institute of Geosciences Journal. Website https://aigjournal.aig.org.au.
Australian Institute of Geosciences Journal. The Lady Loretta PB-ZN-AG Deposit – Analysis of an Opportunity (January 2000).

Glencore. Website https://www.glencore.com.
Glencore. Xstrata Zinc to develop Lady Loretta deposit in AUD246M Project (July 26, 2011).
Glencore. Resourceful. Lady Loretta Mine hits production highs (February 2022).
Glencore. Resources and Reserves Report 2022.
Glencore. Resourceful. Lady Loretta Mine advances its progressive rehabilitation (February 2023).

Mining Weekly. Website https://www.miningweekly.com
Mining Weekly. Curtain falls on Mt Isa underground copper mine (October 18, 2023)