What are the chances of wastewater from the coal-washing process
contaminate surface and ground water, which might cause harm to the
public?
The coal from Hongsa district requires no coal washing, as layers of soil and
coal are clearly separated. Only rain and underground water is present in the
mine. This water needs to be pumped through a series of on-site treatment
ponds, to lower the acid and alkaline levels. Then, the water will be passed
through a large wetland of 230 Rai (370,000 square meters), over 3 kilometers
long, where different types of water plants help filter sediments and absorb
heavy metals. After going through this natural water treatment system, the water
will meet the discharged water quality standards specified by the Government of
Lao in the Concession Agreement. However, to ensure of best results, HPC has
undertaken water quality monitoring on a continuous basis.