Impact of coal mining on surface and ground water quality.

1. By Saurabh Puttewar
IMPACT OF COAL MINING ON
SURFACE AND GROUND WATER
QUALITY.

2. • The Coal Mining industry has to dispose of millions of
litres of water every day.
• The surrounded water resources get affected when the
polluted mine water is discharge into the water system
• Cause of water pollution –
1. Seepage of water from OB, exposed OB.
2. Discharge of effluent from workshop, coal washeries
and domestic effluent from the residential areas.
3. Huge discharge of ash and fly ash and the pollutants of
thermal power plant.

3. Water Quality Standards
Sl. No . characteristics Requirement
(Desirable Limit)
1 Colour 10 Hazen Units
2 pH 6.5 – 8.5
3 Dissolved oxygen 6.0 mg/l
4 Dissolved solids 500 mg/l
5 Turbidity , NTU 10
6 Total hardness 300 mg/l
7 Calcium 75 mg/l
8 Magnesium 30 mg/l
9 Copper 0.05 mg/l
10 Iron 0.3 mg/l
11 Chlorides 250 mg/l
12 Sulphate 150 mg/l
13 Nitrate 45 mg/l
14 Fluoride 0.6-1.2 mg/l
15 Lead 0.1 mg/l
16 Zinc 5 mg/l

4. Causes of deterioration of water quality
Acid mine drainage
• Increased acidity = decreased pH
• Increased metal concentrations
• Increased sulfate
• Increased suspended solids
Silting
• Silting destroy the benthic habitat & reduce availability
of oxygen for benthic animals.
Organic enrichment
• The organic matters are oxygen demanding hence
leading to low DO and high BOD levels in water.

5. Water Quality Parameters
Colour
pH
Dissolved Oxygen
Total suspended solid
Total dissolved solid
Chloride
Sulphate
Nitrate
Calcium
Magnesium
Iron

6. Colour
• Colour varies from brownish to reddish orange.
• Causes- Siltation of coal particles, sand, soil, etc., &
contamination of AMD & formation of iron hydroxide.
pH
• pH value of the water decreases when mixing the
mine effluent.
• The water becomes Highly acidic.
• pH of streams and rivers varies between 2.31 to 4.01.

7. Temperature
• Temperature of the water streams increases after
mixing the mine effluents.
• Temperature of the water stream varies from 24–
27°C.
Dissolved Oxygen
• DO of the water streams decreases after confluence
with mine effluents, because of low DO of mine
effluents.
• Mixing of mine effluent it varies between 4.2 to 5.6
mg/l.

8. Total Dissolved Solids
• After mixing the mine effluent the TDS values of the
water streams increases.
• It varies between 557 to 645 mg/l.
Total Suspended Solid
• Solids such as fine particles of coal, sand, mud & other
mineral particles.
• Water was found turbid & coloured due to suspended
precipitates of iron hydroxides.
• Suspended solid reduce the availability of oxygen and
light for aquatic life.

9. Chloride
• Chloride concentration decreases after mixing with
mine effluent.
• It ranges between 13.96 & 22.39 mg/l.
Magnesium
• Magnesium concentration decreases after mixing
with mine effluent.
• It ranges between 21.36 & 24.25 mg/l.
Iron
• Iron concentration also increases after mixing with
mine effluent.
• It ranges between 0.32 & 20.91 mg/l.

10. Sulphate
• Sulphate concentration between 205.50 & 637 mg/l.
• High concentration of sulphate due to presence of
iron sulphide in coal & rocks and its reaction with
water and oxygen.
Nitrate
• Nitrate concentration decreases after mixing with
mine effluent
• Nitrate concentration Values ranges between 0.1 &
0.4 mg/l.

11. Summary of the physico-chemical composition of water of the Jos
plateau , North Central Nigeria

12. parameters Khliehriat
River- 1
West dkhiah
River-2
Jowai
River-3
WHO BIS
Colour Light Orange Bluish
pH 3.67 3.11 6.67 6.5 -8.5 6.5-8.5
Conductivity (mMHOS) 0.37 0.67 0.10 250 250
DO (mg/l) 4.4 5.72 10.2 6
Magnesium (mg/l) 24.25 21.36 74.08 30 30
Calcium (mg/l) 35.01 35.55 27.70 75 75
Sulphate (mg/l) 492.43 300.3 3.53 250 250
Chloride (mg/l) 22.39 13.94 6.38 250 250
Nitrate (mg/l) 0.40 0.28 0.12 <45 <45
Iron (mg/l) 20.91 12.52 0.09 0.3 0.3
Copper (mg/l) 0.12 0.09 0.02 2 0.05
Zinc (mg/l) 0.70 0.31 0.04 3 0.003
Physico-chemical properties of the water of some
rivers of Jaintia Hills, Meghalaya