The Damang ore body is hosted by a north to north-easterly plunging antiform, developed within Tarkwaian sediments. The main Damang pit is located close to the closure of the antiform, and all other known mineralisation is located on the east and west limbs of the Damang anticline. The mine exploits fresh hydrothermal and oxide mineralisation in addition to Witwatersrand-style, palaeoplacer mineralisation.

Palaeoplacer mineralisation.
There are three gold-bearing conglomerate horizons recognised on the western limb of the Damang anticline. From footwall to hangingwall, these are known as the Star/Composite, Malta/Breccia and Gulder Reefs. There are also three gold-bearing conglomerate horizons recognised on the eastern limb, namely the Lima, Kwesie-K1 and Kwesie-K2 Reefs. These conglomerate horizons are separated by poorly-mineralised sandstone units.

The reefs are usually characterised by a fining upwards sequence of poorly to moderately sorted, clast-supported polymictic conglomerates. However, local variations are observed where the conglomerate domain is interbedded with fine to coarse grained, poorly sorted sandstones. The Star/Composite, Malta/Breccia and Gulder Reefs on the west limb and the Lima, Kwesie-K1 and Kwesie-K2 Reefs on the east limb of the Damang anticline contain higher gold grades than the poorly mineralised sandstone units, which separate the reefs. The conglomerate reefs may contain between 1.3 and 1.5 g/t gold, and the poorly mineralised sandstone units usually contain between 0.1 and 0.2 g/t gold.

Hydrothermal mineralisation.
Hydrothermal gold mineralisation at Damang occurs in pyrite and pyrrhotite alteration selvages, which are usually less than one metre wide and located immediately adjacent to en-echelon quartz veins. Gold is also associated with accessory vein minerals such as carbonate, muscovite, tourmaline, ilmenite and apatite. These alteration zones are often linked and may result in significant volumes, characterised by intense veining and gold mineralisation.

Damang has two open pits constituting the Mineral Reserves, seven open pits comprising the Mineral Resources, three Tailings Storage Facilities: East(ETSF), Far East(FETFS) and South(STFS).

Open pit, conventional drill and blast with truck and shovel. Mining operations are carried out by contract mining. Mining is focused on the Damang complex. Gold mineralisation is mined selectively to cut-off grades (COG) and segregated into grade ranges to balance ore production and processing capacities. The east wall of Damang has been re-engineered to mitigate geotechnical challenges with additional controls being implemented to ensure safe operations.

The Mineral Reserves are constrained by the ETSF, which is adjacent to the east of the Damang main pit, while the Mineral Resources are unconstrained by the ETSF, resulting in 2.29Moz of Mineral Resource gold not yet converting to Mineral Reserves.

Deposition of tailings is currently occurring on the Far East TSF (FETSF), which was commissioned in January 2018. The second stage of the downstream embankment lift, which commenced in November 2019, has been completed. The next stage is planned to commence in 2021.

The ETSF was constructed as a combined TSF and waste dump, using compacted earth fill and fresh waste rock for the embankment construction. The main cross-valley embankments are the north and south embankments. The western side of the facility comprises the Damang open pit and Victoria waste dump, while the eastern side is formed by the eastern embankment which links a series of lowlying hills. Closure deposition of tailings into the ETSF was embarked upon in early 2017 until January 2018 when deposition was ceased.

The FETSF is located south of the existing ETSF abutting the ETSF’s south embankment. The FETSF has been designed and constructed with a compacted clay liner across the facility basin and upstream slopes. The facility is planned to be constructed through four stages and has a remaining LoM storage capacity of approximately 19Mt.The ANCOLD consequence classification for both the ETSF and FETSF is High C. The consequence rating for the STSF will be assessed in Q2 2021.

The Damang mini cutback and full Damang unconstrained studies continue to assess opportunities to extend the LoM beyond 2025, including incremental or full pit cutbacks to access the deeper portions of the ore body beyond the constraints of the current DRP and, specifically, the ETSF. This would require full or partial relocation of the existing ETSF located proximal to the Damang pit east wall and the construction of a new TSF. The project has progressed from scoping study level in 2020 and is now progressing to the PFS phase

The Mineral Reserves are constrained by the ETSF, which is adjacent to the east of the Damang main pit, while the Mineral Resources are unconstrained by the ETSF, resulting in 2.29Moz of Mineral Resource gold not yet converting to Mineral Reserves. This is in addition to the 1.37Moz Inferred Mineral Resource component. Under these constraints, the current LoM extends for another five years and would trigger the mine closure programme in preparation for 2025

ROM ore is crushed using a gyratory crusher followed by a secondary and tertiary crushing stages
in close circuit with two pebble crushers and subsequently stockpiled. Ore is then fed to a milling
circuit consisting of SAG (Semi Autogenous Grinding) and Ball Mill.

Damang Mine operates a carbonin-leach (CIL) processing plant which is fed run-of-mine (ROM) ore at approximately 12,600 tonnes per day (4.2 million tonnes per annum). Plant feed consists of 95% fresh (blasted) hard rock and 5% weathered (oxide) materials.

The milled ore is classified by means of cycloning with the overflow reporting to a pre-leach thickener for thickening to approximately 50% solid density. The thickened leach feed now reports to the eight CIL tanks of 3000 cubic metres each. The final leach tails report to two tails tanks and pumped to the tailings dam. The cyclone underflow returns to the Ball mill for regrinding.

The underflow stream is also bled to feed 2 x 48” Knelson concentrators. The concentrate from the Knelsons is leached directly in an in-line leach reactor at high cyanide concentration. The leach tails from the ILR reports to the Ball Mill for regrinding. The pre leach thickener overflow joins the process water pond as recycled water. Loaded carbon from the CIL is acid washed and eluted at high pressure and temperature. Gold is finally recovered by electrowinning of the pregnant solution and smelting of the cathodes with flux.

The cyanide facilities at Damang Gold Mine are as follows:
• solid cyanide storage area;
• mixing and storage tanks;
• leaching facilities, including CIL tanks, carbon stripping and washing, and in-line leach reactor;
• tailings storage tanks; and
• tailings storage facility and tailings delivery pipeline.