Managing and conserving water

Potential impacts to ground and surface water resources are among the most significant environmental risks faced by the Company’s operations, making it a key point for engagement with communities and other water users who share water resources in the catchment.

Our water management standard mandates the comprehensive understanding of water risks and the implementation of tailored management and monitoring plans, supported by context-specific objectives and targets.

Our operations source water from rivers, lakes or groundwater aquifers, subject to conditions set by regulatory authorisations, often after a licencing process that take into account the needs of communities and other water users in the catchment. In addition, water is often purchased from water utilities and precipitation that falls onto mining infrastructure areas, or groundwater that drains into mine workings, is absorbed into the process water inventory.

A core objective for operational water management is to minimise new water withdrawals from the ground and surface water bodies and to maximise our recycling and reuse of water to the extent possible. Another core objective is to prevent contamination of water resources through our activities. This is achieved by either maintaining zero water discharge on sites, or by treating and releasing excess water from the process circuit, which is typically the case for high rainfall areas.

During 2021, Iduapriem mine’s water treatment facility was expanded to accommodate greater water volumes to be released from the process water inventory during construction and the ramp-up of a planned new tailings facility. Rehabilitation of Iduapriem’s Block 1 waste rock facility, that required active treatment of low pH seepage water, was reworked to encapsulate acid generating rock more effectively, and to reduce rainfall infiltration.

The in-situ groundwater remediation project in Tanzania progressed more slowly than planned, with a joint venture partnership between Sensatec Tanzania and German-based technology provider established late last year. Phase 1 of the production scale project is planned to start in earnest during 2022.

A site-wide water optimisation project started at Tropicana and aims to reduce water abstraction from aquifers and use water by preference, namely water from higher eficiency bores requiring less energy consumption and providing higher water yields, including those around the mine’s TSF. Variable speed pumps with reduced energy usage, operating off the mine’s internal electricity supply grid, have been introduced, eliminating the need for stand-alone diesel generators, which further helps to reduce GHG emissions. The project resulted in an increase of the site’s recycled water and cut diesel consumption for the borefield pumping by up to 35%

Responsible water stewardship is vital for AngloGold Ashanti, with water being a valuable, often scarce resource crucial for a variety of operational tasks and hygiene services.

Prioritised SDGs

Our interaction with water 2021


Water withdrawal (Megalitres)
Group (including sold assets)*33,11847,40548,11345,89252,219
Group (excluding sold assets)*33,11832,00928,08826,92128,241
Argentina 1,4661,3921,5121,5961,487
Cerro Vanguardia1,4661,3921,5121,5961,487
Sunrise Dam2,2471,6571,8981,8081,115
Brazil 9,8069,1847,2686,2176,795
AGA Mineração7,9568,0636,8254,7175,292
Serra Grande1,8501,1214431,5001,504
Ghana 2,5262,133801,6362,137
Guinea 7,7847,4087,0836,0276,349
Mali 04,6575,4094,2013,476
South Africa 010,73814,61714,77020,503
Mine Waste Solutions06,4697,7797,0076,002
Vaal River01,5443,5814,50710,813
West Wits02,7253,2573,2563,688
Tanzania 3,7623,1653,2293,7114,689
Water withdrawal efficiency (Kilolitres per tonne)
Group (including discontinued operations)0.750.680.600.570.61
Group (excluding discontinued operations)0.750.750.690.670.68
Cerro Vanguardia0.500.610.520.550.45
Sunrise Dam0.550.410.460.450.28
AGA Mineração2.
Serra Grande1.500.740.341.291.06
South Africa00.460.420.420.53
Mine Waste Solutions00.360.290.270.23
Vaal River00.670.941.101.36
West Wits00.790.690.690.80

2021 Water Withdrawals by Source (ML)

 Surface water withdrawal related to productionGround water withdrawal related to productionUtility and/or other external water suppliers related to productionTotal Water Withdrawal related to production
Obuasi 2,087 2,087
Iduapriem 388 51 438
Siguiri 7,784 7,784
Geita 3,762 3,762
Sunrise Dam 2,207 40 2,247
Tropicana 5,525 5,525
AGA Brazil (Mineracao) 4,606 3,350 7,956
Serra Grande 1,850 1,850
Cerro Vanguardia 1,466 1,466
Group Total 16,540 16,537 40 33,118

2021 Water reused1

Re-used Water (%)Re-used Water (ML) Water use in production tasks (ML)
Obuasi 63 5,640 8,887
Siguiri 72 32,507 44,985
Geita 65 11,103 17,076
Tropicana 64 10,432 16,263
Cerro Vanguardia 81 7,712 9,564
Serra Grande 63 4,692 7,434
Sunrise Dam 47 2,336 4,999
Iduapriem 82 12,367 15,134
AGA Mineração 51 11,014 21,399
Group 67 97,803 145,740
  1. Water Reporting, Good practice guide, 2nd Edition, ICMM

Group-Level Interactions with Water 1

MetricSource or destinationVolume of water by Quality3
High (ML)Low (ML)Total (ML)
All Operational Sites
Withdrawal for Operational UseSurface water 16,540 0 16,540
Groundwater 8,804 7,733 16,537
Seawater 0 0 0
Third party water 40 0 40
Total Withdrawal 25,385 7,733 33,118
Harvested RainfallDirect Rainfall 10,422 10,422
Indirect Runoff 4,331 4,331
Total Rainfall 14,753 14,753
Discharge from operational systemTo Surface water 10,672 0 10,672
To Groundwater 0 0 0
Seawater 0 0 0
To Third parties 0 0 0
Total discharge 10,672 0 10,672
Operational water consumption (ML) 37,199
Operational water re-use (%) 67%
Operational water re-use (ML) 97,803
Operational water demand (ML) 145,740
Other Managed Water withdrawal 7,077 530 7,607
Other Managed Water discharge 7,077 530 7,607
Other Managed Water consumption 0 0 0
Water Stress Exposure2
Number and Percentage of sites situated in water stressed areas 2 (22%)
Sites located in Water Stressed areas
Withdrawal for Operational UseSurface water 11,546 0 11,546
Third party water000
Total Withdrawal 11,546 0 11,546
Harvested RainfallDirect Rainfall 4,999 0 4,999
Indirect Runoff 1,905 1,905
Total Rainfall 6,9040 6,904
Discharge from operational systemTo Surface water000
To Groundwater000
To Third parties000
Total discharge000
Operational water consumption (ML) 18,451
Operational water re-use (%)70%
Operational water re-use (ML) 43,610
Operational water demand (ML) 62,061
Other Managed Water withdrawal 808 0 808
Other Managed Water discharge 808 0 808
Other Managed Water consumption 0 0 0
  1. Water Reporting, Good practice guide, 2nd Edition, ICMM
  2. Areas with Extremely high (>20%) Unimproved/no drinking water score when assessed using WRI Aqueduct Water Risk Atlas, and local site knowledge.
  3. High Quality: Less or equal to 5000 ppm of Total Dissolved Solids,  High Quality: Less or equal to 5000 ppm of Total Dissolved Solids., Ref: Water Reporting , Good practice guide, 2nd Edition

2021 Water Diversions & Discharges

Location and Source Destination Treatment pH Conductivity
Volume (ML)
Water discharge from process systems
Cocoruto dam of the Queiroz Plant complex, Brazil. Velhas River Arsenic precipitation. 6.7 2.25 1,440 6,231
Córrego do Sítio process plant, Brazil. Conceição River Arsenic precipitation and pH adjustment. 7.8 5.22 3,340 788
Serra Grande process plant, Brazil. Tributary of the Rio Vermelho River Arsenic precipitation & cyanide destruction. 7.5 1.65 1,056 987
OTP Pond, Obuasi mine. Ghana Nyam River Reverse Osmosis 7.3 0.46 307 587
Pond 3, Obuasi Mine, Ghana Nyam River Reverse Osmosis 7.3 0.62 457 2,078
Other Managed Water Discharges (formerly Diversions)
Underground minewater, Cuiabá, Brazil Sabara River pH adjustment with sodium hydroxide. 7.3 0.44 287 224
Undergound minewater, Lamego, Brazil Pataca and Papa Farinha streams Arsenic precipitation and pH adjustment. 8.7 0.86 581 690
Underground minewater, Córrego do Sítio, Brazil Conceição River Arsenic precipitation and suspended solids removal. 7.7 0.86 543 779
Sewerage plant, Córrego do Sítio Mine, Brazil Conceição River Biological treatment and chlorination. 6.0 N/A N/A 59
Palmeiras mine, Serra Grande, Brazil Gerais stream Suspended solids removal. 8.0 0.83 301 443
Palmeiras mine, Serra Grande, Brazil Almas stream Biological treatment and chlorination. 7.5 0.91 560 52
Sunrise Dam Gold mine, Australia Lake Carey (salt lake). None 7.2 227.30 284,500 530
Pompora TSF catchment, Obuasi Mine, Ghana Kwabrafo River Reverse Osmosis 6.8 0.48 327 592
Kami Pit, Siguiri Mine, Guinea Local drainage channel None 6.4 0.63 313 473
Tubani Pit, Siguiri Mine, Guinea Local drainage channel None 6.3 0.50 251 40
Bidini Pit, Siguiri Mine, Guinea Local drainage channel None 6.2 0.38 193 296
Block 7 & 8 pit, Iduapriem Mine, Ghana Agonabeng stream. None 7.6 0.48 262 1, 240
Block 3 pit, Iduapriem Mine, Ghana Agonabeng stream None 8.9 0.31 164 2,190

Acid Rock Drainage

  Global Coverage Obuasi Geita Iduapriem Siguiri Cerro Vanguardia AGA Brazil Serra Grande Tropicana Sunrise Dam
Predicted to occur 56%  Yes   Yes   Yes    No   No   Yes   Yes   No   No 
Actively mitigated 100%  Yes    Yes    Yes    –     Yes   Yes     

Water sources significantly affected by withdrawal of water

The 401,000 ha Niger-Tinkisso Ramsar site is an extensive area of river and freshwater ponds and marshes between and around the Tinkisso and Niger Rivers, however its boundaries are not clearly defined. As many as 101,000 ha of the Ramsar site may overlap the (159,000 ha) Siguiri mine concession in Guinea. The mine abstracts less than 0.5% of the Tinkisso River’s annual flow.

Value of environmental fines

A USD 84,000-equivalent fine was paid by the Quebradona project to the Regional Environmental Authority following a violation in La Fea tributary in 2011 (Note: this is below the significance threshold of USD 100k).

Cuiaba mine was levied a fine over equivalent to USD 141,500 following a 2020 environmental incident, however the appeal process continued during 2021.

Number of non-monetary sanctions in 2021

Nil to report for 2021.

Reportable environmental incidents

Reportable environmental incidents (number)

Reportable Incident Summary

Event Type Site Date Event Summary
Process water spill Obuasi 17 March 2021 An HDPE pipe, that transports underground mine water to the process plant area, was found leaking behind the KMS Shaft’s compressor house. It had failed at a fusion joint. The spill was estimated as 270m3 and contained dissolved arsenic in excess of the Ghanaian discharge limit. It entered the nearby stormwater drainage system and made its way into a wetland.   After switching off the pumps, the joint was rewelded and the system was restarted. Precautionary measures to reduce pipeline pressure were later taken. Water samples taken along the discharge path showed that the spill was diluted shortly by the streamflow volume, shortly after entering the wetland.
Process water spill Cuiaba 01 April 2021 A PVC pipeline conveying excess spillage from the milling and flotation plant to the mine’s new tailings filtration and drying area failed, releasing sediment-laden water onto access roads within the immediate area. A portion of the spill entered a nearby stormwater channel and reached the Sabará River, impacting it visually over a length of about 40 metres. While water analyses in the impacted zone did not reflect a determinable impact on water chemistry, the spillage included constituents marginally above applicable release limits. Approximately 90 m3 of sediment was recovered from the impacted area. The PVC pipeline was replaced with a more durable HDPE pipeline and additional monitoring cameras were installed along the pipeline, as was the frequency of physical inspections.
Tailings slurry spill Córrego do Sitio 05 May 2021 A concrete channel transporting tailings slurry by gravity from the process plant to the mine’s Tailings Storage Facility, overflowed at an inspection point, where it was uncovered. An estimated 30m3 of tailings spilled over into an adjacent concrete channel that drains treated mine effluent water from the process plant to the Conceição river. The tailings flow was stopped and the event was communicated to the relevant authorities and representatives of downstream communities. Samples of the spill-impacted effluent water indicated that the legal release limit for dissolved arsenic, manganese and total suspended solids had been exceeded. Upstream and downstream water quality analysis continued during clean-up activities that we immediately initiated and completed by May 27th. Additional information was requested from AGA after inspections by the State Env Agency, National Mining Agency, Environmental Police and the State Public Attorney. On Aug 27th a notice of violation and associated fine of R$ 183k (US$35k) was received from the authorities. Measures to prevent a recurrence include installation of physical barriers between the two channels, and monitoring cameras at points of high-risk.
Process water spill Obuasi 10 June 2021 Staff at Obuasi’s South Processing Plant discovered an estimated 3m3 of process water seeping into the stone pitched drain that transects the process plant, and directs rainwater from higher-lying ground off the operational area to a downstream watercourse, via the central Channel 13. Plant operations were immediately shut down and water samples were taken at four different locations; from Channel 13, the Nyankumasu watercourse, up to the downstream Nyam river. Cyanide concentrations in the Nyamkumasu stretch were found to be above the permissible limit, but within the standard at the Nyam river sample location. The water sampling continued up to June 13, to confirm the situation had fully normalised.
Process water spill Córrego do Sitio 15 July 2021 Volumes of water being pumped to surface from the Córrego do Sitio I underground mine, for treatment and release, exceeded the storage tank’s capacity. This resulted in an estimated overflow of approximately 500m3 of untreated mine water reaching the downstream Conceição River. The untreated water contained high levels of suspended solids and dissolved arsenic levels marginally over the release limit. Once detected, the overflow was stopped and field sampling initiated. While the event did not trigger regulatory reporting thresholds it was classified as ‘High’ in accordance with AGA’s environmental incident management standard. Investigations revealed that flow rates from the mine had increased progressively, placing pressure on the flexibility of the water treatment system. Measures to prevent recurrence included review and amendment of the facility’s water treatment capacity, and improved control and information systems for operators.