I Executive Article I
“I should hasten to mention that as a responsible management, we have already implemented a number of measures to avert a significant impact of the predicted slough on people, essentially communities around the mining area and our employees. I must state in no uncertain terms that our priority is to ensure the safety of people first, and also make sure that KCM, public and private property are safe-guarded.”
Chief Executive Officer (CEO)
Konkola Copper Mines (KCM)
Konkola Copper Mines (KCM) Chief Executive Officer (CEO) Christopher Sheppard has announced that the mine has predicted an impending slough (Caving in of ground) after its geo-technical assessments detected some slope instability at the Nchanga Open Pit (NOP) Cut 2 in Chingola. The anticipated slough is manifesting through a series of multiple tension cracks, which have continued opening up almost parallel to the strike of the open pit east perimeter road in a South East–North West direction.
Addressing the media in Chingola on the 2nd of July, Mr Sheppard indicated that preliminary indications have shown that the slough will be confined to a stretch of approximately 350 metres and the estimated volume of the area that would be involved in the failure is 8 million cubic metres (20 million tonnes).
The real time slope stability monitoring radar station is currently tracking the increasing movement of the slope inside the open pit and current predictions are that the open pit slope will fail anytime between, 2 July and Tuesday 7 July, 2020.
He said, “I should hasten to mention that as a responsible management, we have already implemented a number of measures to avert a significant impact of the predicted slough on people, essentially communities around the mining area and our employees. I must state in no uncertain terms that our priority is to ensure the safety of people first, and also make sure that KCM, public and private property are safe-guarded.”
The mine has demarcated a hazard exclusion zone, which is 90 metres thick to provide for an acceptable factor of safety. The exclusion zone in which the slope failure will take place is thus at least 60 metres away from the nearby communities of Nchanga North (Buyantanshi Township and in particular Buntungwa Ward).
“All the structures within Nchanga North are situated on competent, stable basement rock which will not be effected by the sloughing of the open pit slope,” he added.
The CEO noted that KCM is currently rerouting power lines and water pipes, which carry water from Kafue Pump Station to the Nchanga Smelter and Mulonga Water and Sanitation Company on a stretch of approximately 650 metres and hoped works would be completed in the shortest possible time to avoid major disruptions to power and water supply.
In order to prevent inadvertent entry of nearby residents into the hazardous exclusion zone, members of the Zambia Police and KCM Security have been deployed full time to the perimeter of the exclusion zone.
The mine has been engaging various stakeholders including the Central and Local Government authorities, civic and community leaders in sensitising people to find common solutions together.
Failures similar to these have been predicted in the past with accuracy with one of the most significant ones gracing Rio Tinto’s Kennecott Bingham Canyon Mine in Utah in April 2013.
With slope monitoring data, the failure was identified some months prior to failure and mining operations ceased in the area of concern. Once the likelihood of failure had been recognised and evaluated, the mine communicated the issue to staff and the local community. The mine had been monitoring movement and when deformation increased, from 1 mm a day to 5 mm day, they pulled out all workers. A fine testament to the engineers who study rock and soil slope stability in the open pit mine context.
When failure occurred it manifested as some 145M tonnes of material which flowed into the pit bottom