Mine Closure Planning Issues and Strategies in Neyveli Mines by Using

Open Source Software

Author- Atun RoyChoudhury & Dr. V Arutchelvan

M.E. (Environmental Engg)

OCTOBER, 2016

Outline...

Overview. What is mine closure. Traditional closing approaches. How we did it differently. What makes for good practice. Real time modelling on NLC India

Limited. Conclusion.

Overview...

Mines only have a limited life span.

Upon end of life, operations must be consolidated and closed.

Include all matters regarding structures, wastes, residue deposits, water management, community relation etc.

The physical activities that are needed to close down a mine are relatively straight forward- Greater challenge today involves leaving a social & environmental legacy.

What is mine closure...

Planning for mine closure should start before mining commences.

It should continue throughout the life of the mine until final closure and relinquishment.

A mature discipline, complete with higher level management process, continuing growth in technical fields enhances mine closure techniques.

New interests in stakeholders and sustainability issues makes mine closure planning more complicated

Traditional closing approaches...

Comparative study of mine closure policy in Australia, Canada and India.

Study area...

Neyveli is located in Tamilnadu, approximately lies with latitude 11.5927°N and 79.4713°E. The township covers 53 Km2 provide around 18000 houses for the employees.

UTM co-ordinates of the area of interest.

Guidelines for preparation of mine closure plan in India. The Central Government vide Notification No. GSR

329 (E) dated 10.04.2003 and No. GSR 330 (E) dated 10.04.2003 amended the Mineral Concession Rules, 1960 and Mineral Conservation and Development Rules, 1988 respectively.

As per these amendments all the existing mining lessees are required to submit the "Progressive Mine Closure Plan" along with prescribed financial sureties within 180 days from date of notification.

Salient features of Neyveli Mines...

Probable closure reasons of Neyveli mines... Closure due to

resource depletion. Closure due to

economic reasons. Closure due to

cessation of open pit or underground workings.

Closure due to geological or Geotechnical reasons.

Closure due to flooding.

Table shows basic reason of mine closure.

*Reference; David Laurence, 2006

Prevailing geological conditions.

Ground water aquifer...

A huge reservoir of ground water occurs below the entire lignite bed, exerting an upward pressure of 6 to 8 kgf/cm2.

Ground water pumping from mines takes place at the rate of 110 Mm3 / annum.

45 numbers of 1000 GPM pumps (20” dia) has generally been used for successful execution of the work

The quantity of water pumped out has been reduced from 50,000 GPM to 32,000 GPM.

Vertical cross section of NLC soil profile...

Prevailing climatic condition The Mine is mainly located in a

monsoon and cyclonic area.

The average rainfall in a year comes to about 1200 mm.

The wind velocity goes up to 160 KM per hour.

Ground water control operations...

Ever since July 1961, the pressure surface is being controlled through pumping from large diameter wells (Drilling: 36 inches/Casing:20inches) strategically located at pre-determined places.

Effective pressure control is achieved from the upper confined confined aquifer alone, constituting the first 30 to 40 m of the aquifer zone immediately below lignite.

Storm water control operations...

The pumps are of varying capacities Viz. 1000, 2000, 4000, and 5000GPM are used for dewatering the storm water and seepage water.

Storm water control pumps are generally placed in Floating pontoons for achieving better results.

Ground & storm water removal arrangements...

Contouring to ensure drainage. Digital elevation

modelling contains all the 3D information about the terrain.

It is possible to calculate a hillshade, which is a raster, that maps the terrain using light and shadow to create a

3D-looking image.

Contouring on Chrome window (offline module). Contouring has been done by using terrain data collected

from Open Source Geospatial Foundation (OSGeo) website. It has been generated at an interval of 10m.

Drainage path according to relief...

Design drainage...

Here the drainage facility has been designed by using QGIS software with existing ground conditions and available hydraulic gradient.

When things go wrong...

Four separate mines in closure proximity in klerksdrop, Orkney, Stilfontein and hartebeesfontein (KOSH area).

Dispute arose over responsibility for pumping of underground water after mine closure

Results...

In case of confined aquifer, it exerts 50-100 tonnes/m2 on the existing upper lignite base stratum.

It’s absolute to results in flooding of both the mine.

Study shows this mine could be closed after a flood carried away the peat resource downstream.

Caution of flooding due to artesian phenomenon...

Final catastrophe, leads to mine closure...

Conclusion...

The analysis of Neyveli mines was performed with the aim of extracting useful information for planning interventions towards the improvement of the existing pressure relief system.

In this paper, the complete workflow has been discussed, starting from the generation of contours to the designing of appropriate drainage pathway.

OSM and Google satellite has been used to bring the model into reality.

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Resource Policy, 3, pp 39-54.  Banerjee, S.P., (2005), A review of the environmental management practices in the Indian mining sector, Tidee, 4(2), pp 127-136.  Bhagawat, R., (2005), Application of remote sensing and GIS, Land use/land cover change in Kathmandu Metropolitan city, Nepal,

Journal of Theoretical and Applied Information Technology, pp 80-86.  Butler, A.R. and Wagambie, D., (2012), The integration of indigenous knowledge into mine site rehabilitation and closure planning at

Ok Tedi, Papua New Guinea’ in A B Fourie and M Tibbet (EDS) Mine Closure, pp 623.  Campusano, R.F., (2001), Mine closure policy, earth summit and the MMSD report, fourth environmental cooperation workshop,

ECOW, GEMEED-APEC.

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Australia, World Review of Business Research, 5(3), pp 140 – 159.

Thank you one and all for your kind listening...

Time for some questions