Reportable environmental incidents at AngloGold Ashanti operations in 2010
These 2010 incidents have been assured by Ernst & Young.
The company requires sites to report all environmental incidents that are high, major or extreme. A total of 27 reportable incidents were reported in 2010 (2009: 51*).
In the South African region eight incidents occurred at our West Wits operations and two at our Vaal River operations.
Owing to heavy rainfall during the wet season and insufficient storage capacity, the North Boundary Dam at West Wits overflowed during the months of January, February, March and December 2010. A capacity upgrade project is in progress and will be completed in early 2011. Also attributable to excessive rain, the South Return Water Dam overflowed and water reticulation changes were made to increase the water intake rate. However, between April and June 2010, overflows recurred on three occasions. The AngloGold Ashanti West Wits Water Steering Committee was convened to refocus process water management on a mine-wide scale.
In the Vaal River area overflows occurred at the Bokkamp and Kopanang Bleed Dams. The West Complex Stormwater Dam was completed to overcome limited storage capacity at the Bokkamp Dam facility and at Kopanang an alarm was installed to alert operators when levels reach 80%.
In Continental Africa, five incidents were recorded at Iduapriem mine in Ghana, six at Obuasi mine in Ghana, three at Siguiri mine in Guinea, one at Sadiola in Mali, and one at Geita mine in Tanzania.
The episodes at Iduapriem were directly related to the tailings storage facility (TSF) at the mine and resulted in the suspension of operations at Iduapriem for a period of two and a half months. Work to find a long term remedy will continue in 2011.
At Obuasi in January and February 2010, tailings was spilled as a result of pipeline ruptures. On each occasion the operations were immediately stopped, the damaged pipelines replaced and the affected areas cleaned up. Treat and discharge activities in Obuasi caused elevated cyanide concentrations in the Nyam River and the death of a small number of fish. The river was flushed and monitoring conducted until levels had dissipated.
A review was conducted at Obuasi in late March 2010 to check on the status of its environmental compliance. It identified that Obuasi has been issued with four directives from the EPA since September 2007 and that important actions relating to the quality of discharge water were not fully implemented. Processing was suspended on 24 March 2010 pending a review of the mine’s water discharge arrangements. The mine’s water management arrangements were amended to maximise the recycling of process water on the mine to ensure that excess process water be treated to a dischargeable quality. This change however, required that additional water treatment and storm water attenuation facilities be established. Gold processing operations recommenced on 30 March 2010 after a five day stoppage that enabled high process water inventories to be managed without being discharged to the environment.
Following two incidents related to the TSF at Siguiri, uncontained water found its way into water courses outside the TSF area and resulted in the deaths of a number of fish. Water samples were taken until pollutant levels dissipated.
Also at Siguiri in the third quarter of 2010, tailings spilled from the TSF discharge line near the Fenserekole Village. The slurry shot about 4m into the air and covered about 1.5ha of a 6ha cassava and maize farm. The process plant was immediately stopped to reduce the pressure in the tailings pipeline and the local authorities and environmental officials in Siguiri were informed. Hydrogen peroxide solution was added to break down the cyanide still contained in the tailings and access control to the affected area was implemented until safe levels were assured through the continuous monitoring programme implemented.
* This number has been re-stated from 50 in the previous report and refers to a tailings spill as a consequence of a burst pipeline at Obuasi in Ghana in late 2009. Operations were ceased immediately and the damaged pipeline was replaced.
An organophosphate pesticide used in the control of malaria was disposed of into a drain at the Sadiola mine clinic resulting in final effluent water being contaminated and poisoning a large number of birds. Contaminated water was pumped from the final effluent basin to an emergency storage area. The downstream water was diluted with clean water whilst being sampled and analysed to ensure it was safe.
At Geita mine, two birds were inadvertently killed after ingesting pool water containing residual levels of cyanide. The cyanide addition rate had been raised in the processing plant to maintain gold recovery efficiencies. The installation of an automatic dilution circuit to reduce the resultant elevated cyanide levels in the tailings was in progress when the incident occurred and commissioned by the end of October 2010.
The Americas reported one environmental incident at Cerro Vanguardia mine in Argentina when an excavator rupture caused tailings spillage. This was immediately cleaned up and an investigation was conducted and measures implemented to prevent a recurrence.
|Ground water used 2009||5710|
|Ground water used 2010||7146|
|Surface water used 2009||3427|
|Surface water used 2010||3764|
|Utility and/or other external water suppliers 2009||10513|
|Utility and/or other external water suppliers 2010||9986|
|Ground water used 2009||6107|
|Ground water used 2010||4748|
|Surface water used 2009||19203|
|Surface water used 2010||18607|
|Utility and/or other external water suppliers 2009||1034|
|Utility and/or other external water suppliers 2010||1080|
|Ground water used 2009||3703|
|Ground water used 2010||3429|
|Surface water used 2009||0|
|Surface water used 2010||35|
|Utility and/or other external water suppliers 2009||0|
|Utility and/or other external water suppliers 2010||21|
|Ground water used 2009||889|
|Ground water used 2010||1503|
|Surface water used 2009||2682|
|Surface water used 2010||2638|
|Utility and/or other external water suppliers 2009||1854|
|Utility and/or other external water suppliers 2010||1676|
|Ground water used 2009||16426|
|Ground water used 2010||16856|
|Surface water used 2009||25312/td>|
|Surface water used 2010||25044|
|Utility and/or other external water suppliers 2009||13401|
|Utility and/or other external water suppliers 2010||12762|