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OVERVIEW OF THE IMPACT OF MINING ON THE ... - IIED pubs

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5.3.3 Alluvial mining<br />

None known and none anticipated.<br />

5.3.4 Monitoring systems<br />

The Department of Water Affairs and Forestry (DWAF) regularly monitor flows and water quality at the Loskop<br />

Dam, as well as other upstream and downstream sites. In addition, DWAF also regulate the quantity and quality<br />

of all effluent discharges through a system of effluent discharge permits or licences. Each licensed effluent<br />

discharger is required to carry out a routine monitoring programme of the flow and quality of their effluent and<br />

supply this to DWAF. The Department then conducts a randomised series of audit samples to check the<br />

veracity of the effluent returns submitted by each discharger.<br />

5.3.5 Water quality data<br />

A selection of water quality data have been obtained to demonstrate some of the different effects that deep<br />

versus shallow coal mining has on water quality, and to show the changes that take place when mine water<br />

seeps, or is discharged into, surface streams (Table 5.6).<br />

Table 5.6: Selected water chemistry data for water samples from a deep underground coal mine, a shallow<br />

underground coal mine and three surface water (stream) samples collected at different distances from their<br />

shallow underground coalmine source. (Data adapted from Hodgson & Krantz, 1999).<br />

Parameter<br />

Deep<br />

Underground<br />

Mine<br />

Shallow<br />

Underground<br />

Mine<br />

ccc<br />

Sampling Sites<br />

Surface Flow<br />

(Close to<br />

source)<br />

Surface Flow Surface Flow<br />

(0.75 km (1.5 km from<br />

from source) source)<br />

pH 8.06 6.78 3.41 3.20 3.12<br />

EC (mS/m) 164 228 120 212 219<br />

Ca 186 561 60 139 144<br />

Mg 89 107 38 83 91<br />

Na 120 15 46 44 40<br />

Cl 13 3 66 52 44<br />

SO4 910 1,767 562 1,460 1,509<br />

Al - < 0.1 27 110 107<br />

Co - 0.04 0.92 1.63 1.58<br />

Fe - 21 2.7 5.6 11.8<br />

Mn - 3.2 25.5 37.5 36.7<br />

Ni - 0.1 0.39 1.13 0.94<br />

Zn - 0.36 0.74 2.05 1.95

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