Overview

Mine Type	Underground
Status	Active
Commodities	Gold
Mining Method	Longhole stoping
Backfill type	...
Production Start	...
Snapshot	Balmaine has not been able to produced saleable gold from its Ballarat mine since October 2022, when the Victorian Government ordered the company to cease depositing wastes in the tailings storage facility. As of February 27, 2023, the Ballarat Gold Mine is now fully operational. Balmaine Gold Pty Ltd, has been placed under voluntary administration with effect from 9 March 2023. On July 15, 2023, the Administrators, Hall Chadwick has listed the mine sales campaign process. During the ongoing sales process, the gold production activities have remained uninterrupted. The administrators have been overseeing and enhancing the mining operations in collaboration with external mining consultants. Additionally, efforts to expand the tailing storage facilities have been progressing steadily.

Deposit type

• Orogenic
• Vein / narrow vein

Summary:

The Ballarat goldfield is positioned in the hanging-wall of the crustal-scale north-south striking, west-dipping Williamson Creek reverse fault. Three north-trending mineralised zones are identified in the Ballarat goldfields: Ballarat East, Ballarat West (including Ballarat South) and Little Bendigo. Gold mineralisation is hosted by Ordovician turbidites of the Castlemaine Supergroup.

The Ballarat Goldmine is located in the Ballarat East goldfield and lies on the eastern limb of the Ballarat Anticline. The turbidites were folded into a series of north-south trending, tight, upright chevron-style anticlines with wavelengths ranging from 50 m to 300 m. Numerous parasitic folds occur around the hinge zones of the larger folds. The three major fold lines of the Ballarat East goldfield are the Sulieman, Scandinavian and First Chance Anticlines.

The Ballarat goldfields are divided into multiple ‘compartments’ by a series of major faults referred to as cross courses. Cross-course faults are sub-vertical, brittle faults that are un mineralised yet play an important role in the distribution of mineralisation, and gold tenors are relatively consistent within individual compartments. Cross courses typically trend northeast or northwest and have displacements ranging from centimetres to several hundreds of metres.

The Ballarat goldfield is an orogenic gold deposit. Vein mineral assemblages include several generations of quartz with chlorite, sericite, albite and carbonate minerals. Arsenopyrite and pyrite are the dominant sulphide minerals with galena, sphalerite, chalcopyrite and pyrrhotite also commonly observed. The estimated percentage of sulphide minerals in the veins is 2%. The host rocks show bleaching, carbonate aggregates, disseminated pyrite, arsenopyrite and pervasive halos of sericitic alteration around quartz veining.

Mineralogical observations that gold may occur in fractures within sulphide minerals or attached to the margins of sulphide grains indicate that gold was deposited after the sulphides. Gold occurs as native gold particles that range in size from several microns up to 30 mm.

The Ballarat Goldmine has three major productive lines of reef, located on anticlines of the same name: the Sulieman minor Line, the Scandinavian Line and the First Chance Line. A minor gold bearing line is the Oregon line to the east of current development. The major folds are continuous along the length of the goldfield. Each line of reef is divided into several compartments ranging in length from 150m to 500m along strike.

Gold mineralisation occurs as en-échelon vein arrays linked to vertically stacked shallow to steep west-dipping reverse faults that cross cut the eastern limb of the anticlines. West-dipping faults are generally narrow (< 1 m wide) and mineralisation is constrained within the fault plane. The Mako Fault Zone (MFZ) in the Llanberris Compartment is an example of a west-dipping reverse fault zone. The fault zones dip between 20o and 70o, extend up to 250m along strike (north-south), 90m down dip and ranges in thickness from 0.5m to 6m. Veining comprises a combination of massive quartz, weakly laminated quartz, brecciated quartz and stockwork veins. Later faults, offsetting early stage veining, have been observed amongst a complex zone of shearing and fault gouge development.

Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

Commodity	Units	2022	2021	2020	2019	2018	2017	2016
Gold	oz	....	....	....	41,830	35,104	41,391	41,516

Operational metrics

Metrics	2022	2021	2020	2019	2018	2017	2016
Annual processing capacity	....	....	....	600,000 t	600,000 t	600,000 t	600,000 t
Waste	....	....	....	227,426 t
Tonnes processed	....	....	....	267,941 t	260,165 t	270,699 t	251,000 t
Ore tonnes mined	....	....	....	273,072 t

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		Sep 7, 2023
.......................	.......................		Sep 7, 2023

Employees	Contractors	Total Workforce	Year
......	......	......	2021
......	......	......	2014