CIMFR Designs First Highwall Mining in India
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ISSN 0409-7467 CIMFR designs First Highwall Mining in India India's domestic energy requirement is met by coal combustion to the extent of about 60%. Currently the country produces about 500 MT of coal per year, 80% of which comes from opencast mines. There has been a great need to substantially increase the coal production in the coming decade to meet our growing economy. Unfortunately, many of Indian opencast mines are reaching their pit limits. Existence of surface dwellings in many places limits the expansion of currently running opencast mines. Also, in many cases the overburden becomes so high that coal extraction becomes uneconomical. But with the use of highwall machines, a cutter is placed on the top of a continuous miner kind of material, and taken through a conveyor inside the seam, which is almost 500-600 m deep inside. That was not possible till now, and large amounts remained untapped owing to limited means and high cost of mining of that seam. Highwall mining is a new technology which can extend the life of opencast mines without disturbing the surface dwellings, and maintaining economy and productivity. This technology is in use in United States and Australia but yet to be introduced in Indian coalfields. It is a remotely operated coal mining technology closely related to underground mining machinery. The method comprises extraction of coal from a series of parallel entries driven in the coal seam from the face of the highwall. These entries are unmanned, unsupported and unventilated. The Central Institute of Mining and Fuel Research (CIMFR), Dhanbad, is instrumental in adapting this new technology for Indian geomining conditions by providing scientific extraction design for the first two Highwall Mining sites at Ramagundem Opencast Project-II of M/s Singareni Collieries Company Ltd (SCCL) and Quarry SEB and AB, West Bokaro of M/s Tata Steel Ltd (TSL). 15 JULY 2009 177 R&D Highlights Plastic state Elastic shear-n shear-p shear-n shear-p tension-p shear-n tension-n shear-p tension-p shear-p shear-p tension-p tension-p Peak strength=8.73 MPa 8.0 7.0 Pa) 6 6.0 5.0 4.0 Vertical stress (X10 3.0 2.0 x 1.0 2.0 3.0 y x Vertical strain (x10-3) Fig. 1 : Elastic model geometry of OCP-II highwall mining of SCCL Fig. 2 : Stress-strain curve and plasticity states of a Model of OCP-II, SCCL Fig. 3 : ADDCAR Highwall Mining in operation at Miller Brothers Fig. 4 : View of 15 working benches of both Coal and OB of Quarry-SEB of Coal LLC, Kentucky, USA M/s Tata Steel Limited (TSL), West Bokaro where CIMFR-designed highwall mining would start shortly Indian geomining conditions are Mining operations, maximum coal Mining team visited USA to gather found to be widely different from recovery and protection of surface practical experience on Highwall those existing in other parts of the and sub-surface properties. Coal Mining operation and meet world, with the existence of multiple recovery of up to 60% has been renowned experts, so that in future, seams and frequently varying designed by CIMFR at the above this type of work can be carried out geology. CIMFR had conducted a mining sites. In the process, novel at any complex rock-geologic series of numerical modelling approaches for pillar designing have condition with much ease and studies coupled with empirical also been formulated specifically for confidence, using formulations and approach and decades of experience long and slender web pillars formed base-data generated by CIMFR and in coal mine geomechanics to come during Highwall Mining operations. other Indian organizations. They up with optimum highwall mining Recently Dr John P. Loui, acquired reach experience, extraction designs. The designs also Scientist-‘EI’ and Dr P. Pal Roy, knowledge and understanding by consider safety during Highwall Scientist-‘G’ of CIMFR Highwall visiting Colowayo mine, Denver 178 CSIR NEWS R&D Highlights 9.57 MPa A 9.0 Block contour of Safety factor 0.0 to 0.5 8.0 0.5 to 1.0 XI 1.0 to 1.5 1.5 to 2.0 7.0 2.0 to 2.5 Block State None 2.5 to 3.0 shear-n shear-p 3.0 to 3.5 shear-p 6.0 > 3.0 B Stress (MPa) 5.0 4.0 XU 3.0 XL 2.0 6.0 8.0 x 10-a Strain 9.32 MPa IX 9.0 8.0 VIII 7.0 Block State None shear-n shear-p shear-n shear-p tension-p 6.0 shear-n tension-n shear-p tension-p shear-p Stress (MPa) 5.0 Fig. 6 : Closer view of safety factor contours in (A) Seam XI and (B) Seams XU, XL, IX and VIII of Quarry SEB of TSL 4.0 capability developed by CIMFR, the 3.0 coal mining companies in India and abroad can now procure the 2.0 6.0 8.0 machinery and extract the locked up x 10-a Strain coal resource safely and economically. This noteworthy work Fig. 5 : Stress-strain curves for width/height ratio of 2.5 in has been possible as a result of (a) long pillar (b) equivalent square pillar of Quarry SEB, TSL dedicated involvement of a group of scientists among which Dr John P. where multiple seam Highwall David Newman, President, Loui and Dr C. Sawmliana acted as Mining is undertaken and also Appalachian Mining & Engineering, Project Leaders at both the sites Dr witnessing Highwall Mining Inc., who is active in Highwall P. Pal Roy acted as Coordinator operation at Miller Brothers Coal Mining design in eastern USA. while Dr Amalendu Sinha, Director, LLC, Kentucky and meeting Dr With the scientific design CIMFR provided his skilful advice and guidance. 15 JULY 2009 179 R&D Highlights Indo-German Open Ocean Experiment to Test Effects of Iron Fertilization on Ecology and Carbon Uptake Potential of Southern Ocean (LOHAFEX) he Indo-German Iron Fertiliza- Iron is highly insoluble in sea water, the iron selectively lost, then the CO2 Ttion Experiment LOHAFEX so, unlike the other nutrients, is taken up is returned to the (LOHA in Hindi for iron, FEX for quickly lost in sinking particles. atmosphere within months. Fertilization EXperiment), a Addition of trace amounts of iron to However, the organic particles in the collaborative venture between these waters, whether from natural form of phytoplankton cells and National Institute of Oceanography sources (contact with land masses zooplankton faecal material that of CSIR and Alfred- Wegener and via settling dust blown of the settle out of the surface layer Institute – Helm Boltz Association, continents) or by artificial iron sequester CO2 for longer time scales Germany, was carried out from the fertilization (from a ship releasing depending on how deep they sink. German research vessel dissolved iron sulfate to the surface Carbon transported in particles that “Polarstern” in the southwest layer), results in rapid algal growth sink below 3,000 m is sequestered Atlantic from 7 January to 17 March leading to development of for centuries and the portion buried 2009. The interdisciplinary team of phytoplankton blooms. in the sediments for much longer. 48 scientists from India (29), Phytoplankton grow by taking up Five iron fertilization Germany (10), Italy (3), Spain (2), UK CO2 dissolved in sea water and experiments in the Southern Ocean (2), France and Chile (1 each) on converting the carbon into biomass have created phytoplankton blooms board “Polarstern” closely (organic matter). Because the CO2 but only in the previous experiment collaborated in monitoring the algal dissolved in the ocean’s surface layer EIFEX carried out from Polarstern, bloom expected to grow in the is in equilibrium with the was it possible to actually follow the fertilized patch of ocean and atmosphere, blooms cause a deficit, rain of particles sinking through the studying its effects on the chemistry which is compensated by uptake underlying deep water column and biology for at least 45 days. from the atmosphere. The fate of the because the experiment was carried The results of LOHAFEX will bloom biomass determines how long out in the closed core of a stationary, be of great interest to both ocean this CO2 is retained in the ocean. If rotating eddy. LOHAFEX was also ecologists and geochemists because the organic the minute, unicellular algae matter is suspended in the sunlit surface layer recycled by known as phytoplankton not only bacteria and provide the food sustaining all zooplankton oceanic life but also play a key role - unicellular in regulating concentrations of the protozoa greenhouse gas CO2 in the and a variety atmosphere. of small The Southern Ocean encircling animals that Antarctica is rich in the nutrients graze on nitrate, phosphate and silicon but phytoplankton the phytoplankton growth is limited - within the by the supply of iron which is a surface crucial ingredient of all organisms. layer, and German research vessel Polarstern. 180 CSIR NEWS R&D Highlights conducted in a pre- selected eddy but the 2-Tonne Force Generating Shape Memory size of the patch was twice as large – 300 Alloy Actuator Bank km2 fertilized with 20 tonnes of iron sulfate. s part of the project titled “Deploy Advanced Composites Division of the EIFEX had to be A ment of Mousche Using Shape National Aerospace Laboratories terminated after 35 Memory Alloy” awarded by (NAL), Bangalore. The SMA actuator days while the bloom Aeronautical Development Agency bank moves a distance of 15mm while was still growing and (ADA) under the DISMAS programme generating a net actuator force of over sinking but a 2000 kg (2Tonne) force generating 2000 kg.