Tanzania, North Mara: villagers fearful after mine water containment pond overflows

Water from a storage pond at Barrick Gold’s North Mara mine in Tanzania is seeping through containing walls, leading local villagers to fear their water sources are contaminated. Monitoring equipment detected abnormally low pH levels in the Tigithe River, in the Tarime district in the north of Tanzania beginning on May 4 following a period of heavy rainfall. Villagers reported that the water had turned a reddish colour.

District councillor Agostino “Neto” Sasi [said] that trees along the river banks were dying and that three children and an old man experienced skin problems after contact with the water. “The river has overflowed its banks into the fields and caused crops such as millet, maize and sorghum also to dry up. About five cows have died from drinking water from the river.”

[...] Though the mine is described by Barrick as operating at zero discharge, meaning no water is released back into the surrounding environment, villagers have long complained that the mine has negative effects. “This problem began in 2006. The impact of the contaminated waters of Tigithe river is huge,” according to Machage B. Machage, councillor of Matongo ward. “Cattle are dying from drinking from the river, fish are dying, plants near the river have all dried up and the community is complaining. “The problem intensifies during heavy rains because the water spreads to a larger area, with crops wilting, and the community making big losses.”

[...] [Mining company] Barrick responded quickly [to the reported spill], dispatching experts to the scene. The company’s environmental and water specialists found the river water to be acidic. A sample taken approximately a kilometre downstream found a pH level of 4.8, more than ten times more acidic than the typical pH of rainwater.

“The decreased pH levels are believed to be the primary result of water moving from containment ponds designed to contain water that comes in contact with waste dumps,” Barrick’s PR and communications manager, Teweli K. Teweli wrote in a May 14 statement. The discharge is from a pond containing acidic runoff water from the mine’s waste rock.

“To avoid seepage from the ponds, they are lined with a special PVC plastic liner material that is laid at the base of the pond. However, the liner material has recently been damaged and compromised by thieves. A secondary source is the adjacent temporary ore stockpile, from which water with increased acidity drains as a consequence of rainfall.”

The company statement says the increased water flow in the river has diluted the discharge, and pH levels have returned to normal, but it is also taking further measures.

[...] Councillor Machage rejects the company’s accusation of theft of plastic liner by the community [but Barrick's Teweli K. Teweli claimed that] “the PVC liners in the affected ponds have been replaced more than four times in less than a year”.

Relations between the company and people in surrounding villages are not the best, stemming both from dissatisfaction with the levels of compensation paid to those displaced by the mine when it was established in 2003 and from the belief that the mine has negatively impacted the environment.

Source: Terna Gyuse, IPS, 18 May 2009