Krishna Kant Indian Institute of Management Calcutta

TECHNO-ECONOMIC FEASIBILITY ANALYSIS OF SURFACE MINER Vs SHOVEL IN COAL MINING

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Mining with shovel-dumper combination

Why surface miner ?

Working principle and various mining methods using surface miner

Applicability and Favoring Issues

Advantage with Windrow method

Surface Miners in use

Sustainability with Surface Miner

Cost benefit analysis- a case study

Conclusion

Agenda

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Mining with Shovel –Dumper combination

DRILLING BLASTING

EXCAVATION

UNLOADING AT CRUSHING PLANTHAULAGE 3

Shovel

Drilling Blasting Loading Crushing

Continuous Surface Miner

+ ++

The conventional method of mining includes –

Drilling, Blasting and Face loading. These Mining operations frequently involve a high degree

of environmental disturbance in terms of fly rock, ground & air vibration, dust and noise.

Cost of mining and quality control are the main issues .To overcome the above problems and to minimize the adverse impacts of mining it is desirable to adopt an eco-friendly mining

technology.

Directloading

Crushed

aggregate

Continuouscutting

Clean, level &stable surface

Precisecutting depth

Why Surface Miner?

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The surface miner is crawler-mounted machine having a cutting drum located b/w two sets of crawlers and positioned at the center of the machine.

The drum is lowered and raised by hydraulic system with powerful hydraulic motors thereby varying the depth of cut

The material cut is loaded onto the primary and secondary discharge conveyors for loading the same on to the loading / transporting equipment.

The rear crawler travel at lower level then the front crawlers to adjust to the required depth

Turn Back Method

Working Principle of Surface Miner

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SIDE CASTING

INDIRECT LOADING (WINDROW)

DIRECT TRUCK LOADING

Various mining methods using Surface Miner

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Flat or gently inclined deposit. Best suited for rock compressive strength up to 60 MPa. Less abrasive rock. Non sticky material Thin seams or thin dirt bands Sized material production Environmentally sensitive areas where blasting is prohibited or restricted.

In general surface miners are capable of cutting rocks of hardness b/w 10-80 MPa. Under certain circumstances (E.g. Highly fractured material) even harder material can be cut economically.

Applicability

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Mining coal with a high production and performance rate without using blasting

Environment: Without abnormal sound, ground vibration and dust

Selective mining: Improving coal quality, capable of thin seam extraction

Sized product: Eliminates primary crushing of mineral completely Reduces the

time, effective carrying capacity of haulage equipment fetching more money and

minimizes damage to trucks deployed for loading

Manpower: Needs less workforce as compared to traditional mining with shovel as

excavator

Safety: Safe in Naxalite effective areas as no explosive is required. Also, Hard

surface less chances of fire and slope instability

High available time utilization: No drilling and blasting related wastage of time.

(from approx. 5,000 to 6,000 operating hours per year)

Overall mining cost :Reduces due to no drilling, blasting and primary crushing.

Favoring Issues

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Even and solid surface which was initially produced by the Surface Miners allows effective loading operations for the front-end loaders and the fast and safe operation of the additional trucks.

It guarantees a higher productivity rate for the Surface Miners since there are no waiting times for the trucks involved.

The cut material which has been laid down in advance can be used as a mine stockpile (emergency buffer).

Loading can be done on demand.

L&T: KSM223, KSM 303,KSM304

Wirtgen: 2200 SM, 2500 SM, 4200 SM

Today, more than 120 Surface Miners are used for coal and limestone mining in India Used in Singereni Collieries Company Limited,Mahanadi Coal Fields ,South-Eastern Coal Fields and Central Coal Fields of Coal India Ltd.

Advantage with Windrow method

Surface Miners in use

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We are competing for finite resources in a world that is increasingly focused

on sustainability, so we have to invest in a manner that not only strengthens our

competitiveness but also produces maximum benefit for local communities.

Ingredients of sustainability with Surface Miner :

Environment friendly- better Air quality ,less Noise and vibration

Optimum use of resources in a scientific /systematic manner to extract maximum resources in the most economical scale

Safety -A safe working environment where the employees can meet production objectives without risk of injury

Sustainability with Surface Miner

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10152025303540

Shovel SM(Windrow) SM(Direct)

Loader Cost

Crushing Cost

Blasting Cost

Drilling Cost

Shovel/SM Cost

Assumptions/data taken:

7.5 Million per annum coal excavationVarious figures taken are from practical experience/equipment manufacturersCoal is moderately hard( Compressive strength~14MPa.)Figures may vary for different mining conditions and output required

Remark: Cost incurred due to dilution of coal with waste has not been included

Calculations

Cost benefit analysis-Mandakini Coal Mine

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Electric Powered machines are more cost effective but flexibility is lost.

ROM coal with high quality will be produced due to less dilution from waste by application of Surface Miner.

Surface Miner with Direct Loading gives maximum cost benefits but it requires high level of supervision and control.

The Surface Miner with Loader combination gives the highest selectivity and flexibility in operation involving changing mining conditions .

Combination of Direct Loading by Surface Miner and Surface Miner-Loader combination methods gives best results.

Use of Surface Miner gives other benefits over Shovel like mineral conservation, it is more environment friendly and safe.

It is recommended method in blasting restricted and Naxalite affected areas

Suitable machines/equipment have to be selected by studying parameters

such as ease of rock excavation, ability of high selective excavation, rate of

production and productivity demands, capital and operational cost and mine

features

Conclusion

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http://www.wirtgenindia.com/ http://www.larsentoubro.com/ http://www.google.com Dey, K (1999), Performance Analysis of Continuous Surface Miner in Indian

surface Coal Mines-a case study, M-Tech Thesis, Department of Mining Engg. Indian School of Mines University, Dhanbad.

Sen, P. and Dey, K.(2000), Continuous surface Miner in Indian Surface Coal Mining, A case study, surface Mining (BrounKohle & others),52(2000),No.4 July-August,pp371-376

References

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S.No. Cost in Rupees/MT SHOVEL SURFACE MINER

(WINDROW)

SURFACE MINER

(DIRECT LOADING)

1 Total Owning & Operating Cost per MT 12.42 14.30 24.33

2 Drilling -Total Owning & Operating Cost per MT

2.57 - -

3 Blasting Cost per MT 18.13 - -

4 Primary Crushing-Total Owning & Operating Cost per MT

4.56 - -

6 Loader for loading in dumper -Total Owning & Operating Cost per MT

- 14.92 -

7 OVERALL COST PER MT WITH LOADER 37.69 29.22 24.33

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