Summary

Deposit type

• Hydrothermal
• Vein / narrow vein
• Paleoplacer

Summary:

e protolith of the world class Tarkwaian palaeoplacer deposits, and a post-Tarkwaian deformation event which, led to the formation of orogenic hydrothermal gold deposits in Ghana and other West African countries.

Damang exploits oxide and primary zone orogenic style hydrothermal mineralisation in addition to palaeoplacer mineralisation. The post-Tarkwaian phase of hydrothermal mineralisation overprints the lower grade Tarkwaian palaeoplacer conglomerates.

Palaeoplacer mineralisation
Three main gold-bearing conglomerate horizons are recognized on the limbs of the Damang Anticline within the Banket Series of the Tarkwaian Group. From footwall to hanging-wall (i.e., oldest to youngest), these are 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. The conglomerate horizons on both limbs are separated by poorly mineralized sandstone units. The reefs are usually characterized by an upward fining sequence

Mining

• Truck & Shovel / Loader

Summary:

uni pit. Mining in the Damang main pit was completed in 2022. Mining in the Huni pit was completed in 2023.

Damang completes mining at the Huni and Lima Kwesi Gap (LKG) pits and increases the processing of low-grade stockpiles.

Damang has one open pit constituting the Mineral Reserves, seven open pits comprising the Mineral Resources, one ore stockpile.

In open pit mining, access to the orebody is achieved by stripping the overburden in benches of fixed height to expose the ore below. This is most typically achieved by drilling and blasting an area, loading the broken rock with excavators into dump trucks and hauling the rock and/or soil to dumps. The overburden material is placed on designated waste rock dumps.

Extraction of the orebody involves a similar activity as in stripping the overburden. Lines are established on the pit floor demarcating ore from waste material and the rock is then drilled and blasted. Post blasting, the ore is loaded into dump trucks, based on a defined ‘dig plan’ demarcating the position of the ore and waste boundaries post the heave and throw movement caused by the blasting, and hauled to interim stockpiles or directly to the crusher at the process plant, while the waste is hauled to waste rock dumps.

Damang’s life of mine plan is based on a contractor mining model. Fresh rock and transitional zones are drilled and blasted as 9 m benches that are excavated in 3 m flitches. Oxide material which cannot be “freedug” is blasted using lower powder factors. Conventionally, Nonel detonators and emulsion are used in both fresh and oxide material. However, electronic detonators are used to control the impact of blasting on the pit walls in areas where there are geotechnical challenges. Presplit wall control methods and trim blasting are also used in the fresh zones to ensure stability of the pit walls. CAT 777 trucks haul the ore to the run-of-mine pad and waste to the respective planned dumps.

Dewatering in the Damang and Huni pits, as well as the surface drains and sumps, is undertaken by a combination of diesel and electric pumps. The current annual discharge capacity is about 4 Mm3. The water is discharged into the Lima, Kwesie and Tomento pits and later pumped to the Adjaye dam to serve as raw water source for the processing plant or for dust suppression. Alternatively, when the water quality meets regulatory standards, the water is discharged into the environment.

Equipment and labour requirements
Primary loading is completed by Liebherr R9250 (250 t) and Hitachi 1900-6 (190 t) excavators. Primary haulage is completed with Cat 777F/G (90 t). Major equipment is modelled with an availability of 84 % to 86 % and use of availability of 85 %.

Mining is a continuous operation with 3 crews on 2 X 12-hour shifts.

Mine design
The west wall of the Damang pit includes 80 ° batters at a height of 18 m separated by 6 m wide berms. This geometry produces a 63 ° crest-to-crest inter ramp slope angle. The

Comminution

Crushers and Mills

Summary:

secondary crushing circuit, which is comprised of sizing screens, two secondary crushers, five tertiary crushers, five feeders and conveyors. The primary circuit contains a 750 t/hour single-toggle jaw crusher that can provide consistent feed when the gyratory crusher is down for maintenance. The Pg 19 mm product reports to the coarse ore stockpile, which has a live capacity of 10,000 t and static capacity of 80,000 t.

The milling section produces leach feed at approximately Pg 106 pm and consists of a semi-autogenous grinding (SAG) mill (8 m high by 5.1 m long) and a ball mill (6.1 m high by 9 m long). Both mills have an installed power rating of 5.8 MW.

Beneficiation

• Gravity separation
• Centrifugal concentrator
• Smelting
• Carbon re-activation kiln
• Crush & Screen plant
• Concentrate leach
• Inline Leach Reactor (ILR)
• Agitated tank (VAT) leaching
• Carbon in leach (CIL)
• Carbon adsorption-desorption-recovery (ADR)
• Elution
• Solvent Extraction & Electrowinning
• Filter press
• Cyanide (reagent)

Summary:

gold recovery circuit. The plant has been optimised to process 4.6Mtpa.

The gravity circuit comprises two XD48" Knelson concentrators with dedicated InLine Leach Reactor for intensive cyanidation of the gravity concentrate. The gravity circuit recovers approximately 30 % of the gold. The leached tails from the ILR reports to the Ball Mill for regrinding after the clarified pregnant solution has been transferred to the electrowinning circuit and the remaining solids have been subjected to several wash cycles using raw water.

The leach circuit comprises eight tanks in series, each with a nominal capacity of 3,000 m3 providing a retention time of 3.7 hours per tank. Each tank is fitted with two cylindrical inter tank screens (Kemix MPS 750P type 1 mm apertures) with mechanical wiper blades to keep carbon away from the screen surface and dual open impellers. The loaded carbon is recovered from CIL tank 1 into the acid wash column and acid washed using 3 % strength hydrochloric acid followed by water flushing.

The rinsed carbon is transferred to the elution column where a hot caustic solution (3 % concentration) is circulated through the column via heat exchangers to elute the gold absorbed on the carbon. Elution is carried out at 120 °C at an operating pressure of 350 kPa in the column. The dissolved gold is then electro-deposited onto stainless steel wool cathodes. Barren carbon from the elution circuit is regenerated in a carbon regeneration kiln.

Gold sludge from both the gravity and electrowinning circuits is washed and filtered. The sludge is further refined through smelting and crude doré is poured. Gravity doré bars are approximately 90 % to 95 % gold whereas doré bars from the CIL circuit are dependent on ore feed characteristics and can vary between 65 % and 90 % gold. Doré is dispatched to a refinery for further processing into gold bullion.

Water Supply

Summary:

he mine to abstract raw water from the Tamang Dam, a tributary of Bonsa River, groundwater from boreholes at the plant site and the West Damang townsite for mining and domestic purposes as well as to dewater the Adjaye pond, Damang Cutback Complex, Rex, Lima, Kwesie South, Amoanda and the Tomento pits. In pursuance of the Water Resources Commission (WRC) ACT 522 (1996) and L11692, AGL promptly submits applications for water use permit renewal, quarterly reports and complies with all other issues relating to water use, abstraction, discharges and storage.

Damang Mine has a positive water balance. Over 77 % of the mine’s water use is from recycling return water from the FETSF. Fresh water top up is from the Adjaye Dam which receives water from the active pits or from the mine’s water reservoirs. Inactive pits like the Lima, Kwesie and Tomento pits have been adopted as water reservoirs for storage of excess water from active pits and from runoffs in the wet season. The adoption of the inactive pits as reservoirs has eliminated the need to abstract water from rivers and streams in and around the mine. The approach also ensures adequate availability of water for processing in the dry seasons.

Potable water supply is mainly from groundwater boreholes. Water from boreholes located at various points on the mine are pumped through treatment systems to all areas of the mine including the camp, offices, workshops and the process plant for portable purposes. The mine’s water balanc

Commodity Production

Operational metrics