Osino eyes Khan River water source

Osino eyes Khan River water source

Osino Gold Exploration and Mining and NamWater are seeking environmental clearance for a proposed sand storage dam on the Khan River to strengthen water supply for the Twin Hills Gold Mine near Karibib.

Twin Hills is a developing gold mine about 25 km north-east of Karibib.

The mine entered construction in January last year and is planned as an open-pit operation. Once in operation, it will need about 3 300 cubic metres of water a day, or 1.1 million cubic metres a year, for its initial production phase.

The proposal comes as concerns grow over water security in Erongo. At the recently relaunched Erongo Water Forum, officials said coastal water demand of about 28 million cubic metres a year already exceeds available supply, with growth driven largely by mining, future uranium projects and expanding settlements.

The region relies on groundwater from the Omdel and Kuiseb aquifers and desalinated water, but ageing infrastructure, high costs and limited pipelines constrain supply.

Against this background, Osino is looking at additional water sources for Twin Hills. The mine’s main water source will be groundwater from the Karibib Marble Aquifer.

Regulators have licensed abstraction of 0.75 million cubic metres a year from that aquifer.

Preferred option

The proposed Khan River project would supplement that supply and reduce reliance on a single source. The preferred option is a one-metre-high sand storage dam on the Spes Bona section of the Khan River, designed to slow floodwater and store water mainly underground, reducing evaporation losses.

The broader Spes Bona water option was assessed as being able to supply up to 30% to 40% of the mine’s water demand.

“Owing to its minimal surface water extent, reduced evaporation losses, and lower environmental impact, the 1 m-high sand storage dam is identified as the preferred option,” the report says.

Construction and commissioning are expected to take six to 12 months. Once built by Osino, the dam would be handed over to NamWater, which would be responsible for its operation and maintenance.

The report identifies possible risks, including changes to the Khan River’s flow, impacts on trees that depend on groundwater, possible effects on downstream boreholes, and concerns about water access and fairness.

Public comments on the draft report are open until 26 June