16.07.2008 - 16.07.2008 22 °C
Matla mines are located near Kriel east of Johannesburg and mine coal using a combination of shortwall and bord and pillar methods. Matla No. 2 has extracted from three seams, with a total extraction thickness in excess of 10m. needless to say that its shallow depth creates a signifficant subsidence impact on the surface which needs to be seen to be believed. Because the surface is grass covered it is possible to obsercethe effect of the subsidence troughs by eye. From imagery on Google maps, the location of the chain pillars pillars can be seen along with some surface ponding. Significant surface rehab also takes place. Subsidence monitoring typically takes place using photogrammetry.
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