RUB » Faculty of Civil and Environmental Engineering » Environmental Engineering+Ecology

Mining wastewater - a globally significant water resource can be used for water supply

The WaterMiner R&D project has shown that wastewater, reclaimed from mining activities, can be an important complementary water resource. Even though the quantities and locations where water is extracted, in mining areas, are constantly changing, wastewater from mining can be used as service water or even drinking water with suitable spatio-temporal water management.

Mining is usually accompanied by the extraction of large quantities of water, most of which has so far been discharged, unused. The R&D project "Spatio-temporally coordinated recirculation and reuse of mining wastewater using the example of an urban mining area - WaterMiner" was launched in 2016 and aims to investigate the usability of mining wastewater, as an example.

The project area is located in Ha Long in the north of Vietnam. Hard coal is mined there in opencast and underground mines. Due to the storage conditions of the coal, mining in the project area is constantly changing. In the longer term, the opencast mines will be closed down as part of a structural change of the region in favour of environmental protection, nature conservation and tourism.

Accordingly, the mining wastewater and surface runoff will be spatially and temporally highly variable, which requires special concepts for use. On the other hand, tourism, which is growing strongly in the project area, is associated with an increasing demand for water and is a potential user of treated mining wastewater.

Left: Mining activities in Ha Long (Photo: eE+E), Right: Tourism in Ha Long (Photo: Hien Phung Thu/

For the development of concepts for the use of mining wastewater, a spatio-temporal analysis was developed, with the help of a material flow model and geoinformation systems. It enables the consideration and management of the highly variable wastewater flows in mining, the demand for auxiliary materials and energy including, additionally, the occurrence costs and revenues for water use.

Another aspect of the R&D project is to manage surface runoff in the project area, in the most environmentally sound way possible. For this purpose, a concept for the reduction of sediment inputs and the separation of coal dust was developed. Furthermore, the use of the tailing dams, created in the course of mining for the storage and use of surface water, was considered.

Overall, it could be shown that treated mining wastewater is an essential contribution to meeting the increasing water demand in Ha Long and that improved surface water management can make an important contribution to environmental protection in Ha Long Bay (UNESCO World Heritage Site).

Participants in the current WaterMiner project are: eE+E Environmental Engineering and Ecology in Civil Engineering, Ruhr-University Bochum; Dresden Groundwater Research Centre (DGFZ); LUG Engineering GmbH; Department of Environmental Economics, University of Koblenz-Landau; Ribeka GmbH and Disy Informationssysteme GmbH.

The R&D project took place in close cooperation with the Vietnamese mining company VINACOMIN Vietnam National Coal - Mineral Industries Holding Corporation Limited. The results of the research were presented at a final workshop, jointly organised with the partner VINACOMIN, in Ha Long City on 25 October 2019.

As a follow-up to the project, discussions are being held between VINACOMIN and the local water utility QUAWACO, to implement the concepts developed in the R&D project.

The WaterMiner collaborative project was funded by the BMBF Federal Ministry of Education and Research, under the funding measure "Sustainable technologies and concepts to increase water availability through water reuse and desalination (WavE)".