Contrary to common assumptions, Minister of Environment, Climate and Wildlife, Dr. Sithembiso Nyoni says the pollution of the Deka River in Hwange stems not from current mining activities, but rather from a longstanding issue originating from the discharge of Acid Mine Drainage (AMD) by the old Hwange Colliery Company (HCCL).
In response to public outcry over the pollution of the river which is posing a threat to aquatic ecosystems, human health, and the environment minister Nyoni said there are three distinct discharge points of AMD around Hwange, with records dating back to 1997 indicating the severity of the issue.
“The Deka River issue is of grave concern to the Ministry of Environment, Climate and Wildlife, as it poses a significant threat to aquatic ecosystems, human health, and environment. Contrary to popular belief, the pollution of Deka River is to a result of the discharge of toxic chemicals by current mining companies, but rather a legacy issue caused by years of continuous discharge of Acid Mine Drainage (AMD) from the old Hwange Colliery Company (HCCL) workings.
“There are three distinct AMD discharge points around Hwange ad records show that by 1997, AMD was already a considerable problem. The initial interventions at the first and oldest discharge point started in 2008, involving the construction of a series of holding ponds to increase retention times and acid neutralization using lime.
“Records indicate that on average, liming has helped increase the pH from around 2 to 3, and the holding ponds have since developed into an artificial wetland system. The discharge rate at this site is variable, generally averaging about 16 cubic meters per day, with the pattern unrelated to natural seasons, suggesting it is not directly driven by rainwater recharge,” said Minister Nyoni
Expressing dissatisfaction with the mitigation efforts by the Hwange Colliery Company (HCCL), Minister Nyoni outlined several measures implemented by the Ministry to safeguard water bodies like the Deka River from the adverse effects of mining activities.
“At the second site, the rate of AMD discharge can be as high as about 200 cubic meters per day, with a pH as low as 2.7. The discharge pattern at this site is yet to be established, but it has generally been increasing over the years to the current rate. The third discharge point comprises two plugged exploration boreholes, through which the AMD is still seeping out, indicating significant pressure underground.
“There exists a risk of new discharge points following the plugging of current ones, as records show a surge in AMD discharge at the second site after plugging the boreholes at the third. However, the efforts by the Hwange Colliery Company (HCCL) to mitigate the problem have fallen short,” said Nyoni
She said government will put in place measures aimed at ensuring that mining practices do not compromise the integrity of water ecosystems and the health of surrounding communities.
