It would be quite wrong,however, to assume that all the weathering products of ores and the inorganic and organic reagents used in mineral processes add up to a serious water pollution problem from a normal mineral processing plant.
The fact that this is not the case indeed that measured toxicity and pollution are usually tolerable is attributable to the activity of the freshly ground mineral surfaces
The basic phenomena at work here are as follows.
The mineral particle surfaces exposed for the first time by grinding have a very high chemisorptive capacity, as they have not yet been passivated by permanent adsorption layers.
These unstabilized mineral surfaces are surrounded by microenvironment that usually has a higher ion concentrate including a higher PH, than the ambient water.