Success Experience of NLC in Implementing the Highly Mechanized Continuous Mining Technology at Neyveli
National Workshop on
The Technology Development & Mechanization of Mines
for enhancing Coal Production & Productivity
at
New Delhi on 20.01.2015
“Mission 1 Billion tons”
The one day National Workshop on “The Technology Development & Mechanization of Mines for enhancing Coal Production & Productivity” organized by the Indian National Committee of World Mining Congress with the support of Ministry of Coal, Government of India is a very good initiative to fulfill the “Mission 1 Billion tons”.
In the economic development, you all know that mining is a core industry which has to be managed very well. The absence of due management results in mineral wastage and environment pollution. This amplifies the real urge of Seminars, Symposiums and Workshops like this and I am happy over the huge response from the sponsors and great friends like you indeed.
Mining industry is going to play a pivotal role in meeting the ever increasing demand of minerals and metals to sustain higher growth rate of Indian economy. I would like to share some statistics with the eminent personalities, on certain important issues pertaining to Mining industry.
India, for its sustainable growth, needs energy from diversified energy sources. In the recent years, India’s energy consumption has been increasing at one of the fastest rates in the world due to population growth and Industrial development. It is sorry to mention that the Demand is outstripping supply. But Energy is not easily available in the world market including India. As low cost energy is not just available, growing demand for clean energy coupled with reduction of carbon foot print is ever increasing.
India’s energy supply comes from different sources - Coal, Hydro, Oil & Gas, Nuclear and various forms of non-conventional energy sources. Coal is the most important and abundant fossil fuel in India. It accounts for 55% of the country's energy need. Commercial primary energy consumption in India has grown by about 700% in the last four decades. The current per capitacommercial primary energy consumption in India is about 350 kgoe/year (Kilo gram oil equivalent / year) which is well below that of developed countries. Driven by the rising population, expanding economy and a quest for improved quality of life, energy usage in India is expected to rise.Considering the limited reserve potentiality of petroleum & natural gas, eco-conservation restriction on hydel project and geo-political perception of nuclear power, coal will continue to occupy centre-stage of India 's energy scenario.
India is well-endowed with both exhaustible and renewable energy resources. India has the fifth largest reserves of coal in the world (301.56 billion tonnes). India now ranks third amongst the coal producing countries in the world, producing about 565 million tonnes and imports about 168 million tonnes. Being the major fossil fuel in India till date, Coal continues to be one of the most important sources for meeting the domestic energy needs.
NLC is presently operating four open cast Lignite Mines (3 in Neyveli, Tamilnadu and one at Barsingsar, Rajasthan) with Overburden Removal capacity of 165 Mm3 /Annum and a total mining capacity of 30.6 MTPA linked to four pit head Thermal Power stations with Generation capacity of 2740 MW. With the addition of 500 MW in Thermal Power Station-II Expansion, the total Generation capacity would increase to 3240 MW.
NLC is executing the renewable energy projects like 10 MW Solar power plant at Neyveli and 51 MW Wind power project at Tirunelveli District.
As part of its ambitious growth plan, NLC is venturing in New/Expansion Projects. NLC is currently executing 2X500 MW, Coal based Power project at Tuticorin, through a joint venture company NTPL (NLC with TNEB-TANGEDCO) and 2x500 MW New Thermal Power Project (as a replacement of old 600MW TPS) at Neyveli with expansion of Mine-IA from 3 MTPA to 7 MTPA.
With this the power generation capacity of NLC would be 4640 MW in thermal sector, 51 MW in Wind sector and 10 MW in Solar sector.
The following Projects are under formulation:
Ø 250 MW TPS with 2.25 MTPA Lignite Mine at Bithnok,
Ø 250 MW TPS as Barsingsar Thermal Power Plant Extension with 1.9 MTPA Hadla and augmenting the present capacity of Barsingsar Lignite Mine,
Ø A Joint Venture Coal based 1980 MW Power Project in Uttar Pradesh by NUPPL, between NLC and UPRVUNL,
Ø 10 MW Solar Power Plant at Barsingsar, Rajasthan,
Ø 4000 MW Coal based Coastal Power Project “Sirkali Thermal Power Project” in Tamil Nadu.
GOI has recently allotted 2 Coal Blocks to NLC. One is an underground block named Jilga-Barpali, Mand Coal Fields in Chhattisgarh as a linkage to the proposed 4000 MW Sirkali Thermal Power Project and the other one is Pachwara South Coal Block located in Dumka district, Jharkhand State to feed Coal to the proposed (1980 MW Ghatampur Thermal Power Project at U.P.
As regard to Coal reserves, currently India’s estimated Coal resources stand at 301 billion tonnes of which about 125 billion tonnes or 40% are proved reserves. Similarly, Lignite reserves estimated at 42 billion tonnes of which about 6 billion tonnes or 14% are proved reserves. Efforts are required to bring more reserves to “proved category” to increase the confidence level of the Investors.
Further, vast Coal & Lignite resources are at deeper depth (>200m). Commercial Potential for development of these blocks which are not amenable to Conventional methods requires to be analyzed.
In this context it requires to look into alternate technologies to address the environmental issues, up gradation of Gross Calorific value, exploration of deep seated deposits etc.
Clean Coal Technologies (CCTs like CBM, CMM, UCG, etc) are of paramount important to fulfill the energy demand of the Nation. Few foreign countries proclaim that they have successfully implemented Clean Coal Technologies for exploration of deep seated deposits, up-gradation of Gross Calorific value of low rank Coals/Lignite, minimize CO2 emission etc. However, the above technologies require to be tested for Indian condition.
NLC is contemplating to exploit the deep seated Lignite deposits of Ramnad in Tamilnadu by Underground Gasification Technology.
NLC has developed a Bio-fertilizer namely Humic acid as a by-product from Lignite and obtained Patent rights in the year 2006. NLC is initiating steps to commercialize the product through National Research Development organization (NRD).
NLC has executed an R&D project Utilizing Bottom ash of Thermal Power Plants for Construction Activities as substitute of Fine Aggregates (Sand) in collaboration with Vellore Institute of Technology (VIT) at a cost of Rs. 45.46 Lakhs. An experimental building of 920 SFT has been constructed by Utilizing Bottom ash as substitute of Fine Aggregates (sand).
NLC is the first company having the expertise both in mining of lignite and power generation. Neyveli Lignite Mines play a major role in meeting the energy needs of several states of South India. Due to its excellence in performance, expansion activities and achievements, NLC is conferred with “Navratna” status under the Administrative control of MOC. NLC is identified as Nodal Agency for exploration of Lignite in the country.
NLC has made significant contributions, not only in the area of Production like Mines and Thermal, but also in the field of Environmental protection and Ecological balance. By carefully planning the projects, implementing pollution control measures, monitoring the effects of mining and rehabilitating mined areas, the impact of the mines on the Ecology & Environment of the neighboring Ecosystem is minimized. NLC does not hesitate to walk the extra mile, when it comes to the needs and priorities of the society.
The lignite seam was first exposed in August 1961 in NLC and regular mining of lignite commenced in May 1962.
German excavation technology in open cast mining, using Bucket Wheel Excavators, Conveyors and Spreaders (SME Technology) were used for the first time in the country in Neyveli Mine-I. It is worth to mention here that the Hambach, the largest Lignite opencast Mine in Germany (located in North Rhine-Westphalia) is fore-runner of the state of art of Bucket wheel Excavator technology. The first BWE was commissioned in 1933 in this mine. At present it is claimed that Hambach mine is deploying the world’s biggest Excavator capable of extracting 2.4 LT of lignite/day or 2.4 LCM of OB per day. The mine capacity is 40 to 45 MTPA with OB removal of 240 to 260 Mm3/A . They are deploying 5 nos. of BWEs of capacity 2.4 LCM/day, 2 nos. of BWEs of capacity 2.0 LCM/day and 1 no. of BWE of capacity 1.1 LCM/day. The overburden strata in this mine are loose and it does not require any blasting.
From the initial capacity of 6.5 MTPA, NLC has grown in multifold to a production capacity of 30.6 MTPA with OB removal of 165 Mm3/A in a span of 5 decades. The adoption of Bucket Wheel Excavator technology at Neyveli was a landmark event and it has helped for the multifold growth. Now it has been planned to increase this capacity to 49.0 MTPA of Lignite during 2020-21.
The total SMEs deployed presently at NLC Mines viz. Mine-I, Mine-IA and Mine-II at Neyveli area are summarized:
1) 1400 L BWEs : 13 Nos
2) 700 L BWEs : 16 Nos
3) 20000 TPH Spreader : 4 Nos
4) 11000 TPH Spreader : 7 Nos.
5) 5000 TPH Spreader : 4 Nos
6) 2400 mm Conveyor : 27.34 Km
7) 2000 mm Conveyor : 61.80 Km
8) 2400 mm Conveyor : 27.34 Km
9) 1500/1600/1800 mm Conveyor : 34.08 Km
The configuration of SME equipments deployed in our Mine-II of 15.0 MTPA capacity with an Overburden removal capacity of 78.0 Mm3/A is depicted for your better understanding.
EQUIPMENT CONFIGURATION – OVERBURDEN & LIGNITE ( MINE-II)
SYSTEM / Bench Height / SME EQUIPMENTS / Equivalent CME equipments reqd. / RemarksNew Surface Bench
Capacity
# 21.15 Mm3/A / 25 m / 2* 1400L Bridge Type BWEs
2400mm Conveyor (11.58 Km)
1* 20,000 TPH Spreader. / 26 Numbers shovels of 10 to 12 M3 size with combination of 230 Nos. of 100 T Dump Trucks are required for removal of 78.0 Mm3 over burden. / # Capacity of one 1400 L BWE is 9.0Mm3 for 4000 working hours. By deploying additional BWE during overhaul, working hours of system is increased to 4700 hours and thereby getting increased capacity.
Surface Bench Capacity
# 21.15 Mm3/A / 25 m / 2* 1400 L Bridge Type BWEs,
2400 mm Conveyor (9.64 Km),
1* 20,000 TPH Spreader.
Top Bench Capacity
# 19.575 Mm3/A / 25 m / 2* 1400 L BWE,
2000 mm Conveyor (7.49 Km),
1* 20,000 TPH Spreader.
Middle Bench Capacity
9.0 Mm3/A / 25 m / 1* 1400 L BWE,
2000 mm Conveyor (7.46 Km),
1* 11,000 TPH Spreader.
Bottom Bench Capacity
# 7.125 Mm3/A / 18 m / 2* 700 L BWEs,
2000 mm Conveyor (7.64 Km),
1* 11,000 TPH Spreader.
Overburden
Total capacity / 78.0 Mm3/A
Lignite System Capacity
15.0 MTPA / 18 m / 4* 700 L BWEs,
2000 mm conveyor (9.50 Km). / 5 Numbers shovels of 10 to 12 M3 size with combination of 40 Nos. of 100 T Dump Trucks.
# The capacity of a 1400 lit. excavator for 4000 working hrs., works out to 9.0 Mm3. By deploying an additional BWE as substitute during major overhaul and repairs, the effective working hours of the system could be increased to 4700 hrs. The additional excavator capacity of 9.0 Mm3 was distributed on need based among the overburden systems viz. New Surface Bench System by 3.125 Mm3, Surface Bench System by 3.125 Mm3, Top Bench system by 1.575 Mm3 and Bottom Bench System by 1.125 Mm3.
In order to visualize equipment configuration required in CME for a similar production capacity, I would like to take 10 to 12 cum shovel and 100 T dump trucks as a bench mark.
A 10 to 12 cum shovel will have an annual productivity of 3.0 Mm3/A. It will be required to deploy about 26 nos. of 10 to 12 cum shovels with combination of 230 Nos. of 100 T dumpers for the prevailing leads in Mine-II for an annual productivity of 78 Mm3/A of OB. For Lignite excavation, 5 nos. of 10 to 12 cum shovels with combination of 40 Nos. of 100 T dumpers are required to be deployed for the annual capacity of 15.0 MT. This will amplify the magnitude of OB removal with huge fleet of equipments involved in the mining operations. However the height of each bench and surplus productivity of Shovels may have to be balanced by prudential utilization / placement of Shovels and Dumpers in each system.
SME technology is a continuous mining system. It involves excavating the formation in benches of (approximately) 20 to 25m height in slices of 4 to 6 m using the Bucket Wheel Excavators, transporting the excavated solid waste through Conveyor belts and dumping the material in the dump yard and back filling in the void area generated after advancement of mine.
The lignite mining at Neyveli has twin challenges of handling of Overburden with a tune of 6 Cu. M per tonne of Lignite and adverse hydrological conditions requiring pumping of 8 to 10 Cu. M of water. The lignite is underlined by powerful artisan aquifer which extends around 400 mts below lignite with an upward thrust of 5 to 8 Kg/cm2. The aquifer is made up of alternate layers of sand and clay. Depressurization of aquifer is being done to control the upward pressure for safe mining of lignite. The challenges posed by nature on lignite mining were aptly handled in the Neyveli mines by adopting SME technology and by continuously optimizing the Ground water pumping pattern.