ADDITIONAL DETAILS SOUGHT by EAC For
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ADDITIONAL DETAILS SOUGHT by EAC for Amendment in Environmental Clearance due to Changes in Project Configuration of Kiriburu-Meghahatuburu Iron Ore Mines of SAIL STEEL AUTHORITY OF INDIA LIMITED MECON LIMITED (A Govt. of India Enterprise) RAW M ATERIALS DIVISION Vivekananda Path INDUSTRY HOUSE, 5TH FLOOR PO. Doranda 10, CAM AC STREET Dist – Ranchi, Jharkhand - 834002 KOLKATA – 700017 Certificate no: NABET/EIA/1619/RA 0068 Project Proponent Environmental Consultant Amendment in Environmental Clearance Due to Changes in Project Configuration of Kiriburu- Meghahatuburu Iron Ore Mines of SAIL ADDITIONAL DETAILS SOUGHT BY EAC (Non-Coal Mining) The proposal for Amendment of Environmental Clearance approval letter No. J- 11015/272/2007-IA.II (M) dated 23rd September, 2014 for change in product mix by including excavation and dispatch of tailings from tailing ponds of Kiriburu & Meghahatuburu Iron Ore Mines up to 2 MTPA (1 MTPA from each mine) keeping total production within approved EC capacity of 16 MTPA under Para 7(ii) of EIA Notification was considered in the 14th meeting of the Expert Appraisal Committee (EAC) for Environmental Appraisal of Non-Coal Mining Projects held on 26th February, 2020 (Agenda 2.3) in the Ministry of Environment, Forest & Climate Change, Indira Paryavaran Bhawan, New Delhi. After detailed deliberation, the EAC deferred the project and sought the following additional information : a) PP need to conduct the tailing pond stability studies. b) Transport scenario to be properly calculated and resubmitted. c) Traffic density and road carrying capacity to be calculated, d) Excavation plan to be properly delineated. e) Mass balance to be prepared and quantitative despatch scenario for lump, fines from in suite reserves and tailing pond needs to be submitted. f) Impact on pollution load (increase/decrease) due to proposed excavation & dispatch plan needs to be submitted. Point wise reply to above details are given in the following paragraphs- a) Point 1- PP need to conduct the tailing pond stability studies. There are two tailing ponds one each for Kiriburu Iron Ore Mine and Meghahatubutu Iron Ore Mine for storage of tailings generated from ore beneficiations plants and solid– liquid separation. The Tailing ponds areas at both the mines are shallow natural depression surrounded by natural ridges. These Tailings Ponds were constructed by means of earthen dams joining the hillocks. The details of the tailing ponds at these mines are as follows: Tailings Pond at Kiriburu Iron Ore Mine: The tailings generated from Kiriburu Ore Beneficiation Plant are conveyed through 12’’ dia and 2.4 km long pipe line by gravity to the tailings pond. The tailings pond at Kiriburu Mine was constructed during early seventies with a catchment area of 107 ha. It is submitted that the site for the tailings pond was selected taking into account of topography, geology & catchment area. Considering local geology and soil characteristics, earthen dam was considered suitable. Since it is possible to keep on raising the dam height to a certain extent, it was planned to execute the tailings dam work in two stages to keep down the expenses and also to keep the door open for taking advantage of any technological advances for use of tailings. In 1st phase, the dam height was kept at 29 m at which about 2.4 million cubic metres tailings can be stored. In final stage the dam was proposed to be raised to a height of 40 m, when it will have an ultimate capacity of 4.35 million cubic metres. ADDITIONAL DETAILS SOUGHT BY EAC IN THE 14th MEETING Page 1 HELD DURING FEBRUARY 26-27, 2020 © 2020 MECON Limited. All rights reserved Amendment in Environmental Clearance Due to Changes in Project Configuration of Kiriburu- Meghahatuburu Iron Ore Mines of SAIL Presently, the tailings dam is in 1st phase with a capacity to hold 2.4 million cubic metres with dam height of 29 m. As stability of the earthen dam is largely influenced by construction and process, special attention was paid while constructing the dam to safe against (i) over topping (ii) seepage (iii) sudden draw down and (iv) horizontal sliding. Further, the dam to be safe against the over topping, the height of the dam was kept at 32 m to prevent over-topping and sufficient spill-way capacity of 45 m2 by taking into consideration of the maximum flood water that will flow when the reservoir is full. The salient features of the tailings dam are as follows: Catchment area : 1.07 sq. km or 107 ha. Rainfall intensity (max) : 90 mm per hour Bottom Level : 592 m RL Dam Top Level : 624 m RL Top Length and width : 230 m & 6 m Capacity of the dam : 2.4 million m3 (about 4.8 million tonnes) Bottom width : 233 m Maximum D/ s : 143 m Maximum U/s : 90 m Side Slopes (U/s and D/s) : 1 in 2.5 Maximum depth from top: Upstream : 32 m Downstream : 39 m Filter blankets in successive layers were provided over foundation of tailings pond to facilitate seepage of water and to prevent erosion of soil or damage of over lying structures from uplift pressures. A spillway of 30 m x 1.5 m with a slope of 1 in 100, at 3 m free board has been provided and pitched with cement grouted laterite boulders of 300 mm thickness. A curtain wall on the lower side to avoid damage due to erosion to the lower end pitched surface is also provided. Presently, the tailing pond is mostly filled and contains about 4.5 million tonnes of tailings. In order to increase the holding capacity of the pond and to facilitate de-silting of tailings, internal bunds have been made within the pond. Further, system for recovery and recycling of clear water from tailings pond has also been implemented. This reclamation of water is being done by setting up pumping station at tailing pond in two stages through a pipeline of 400 mm diameter pipes. Two sets of pumps with all the accessories have been installed with capacity of each set 250 m3/hr i.e., 500 m3/ hr for reclamation & recycling of clear water from the tailing pond. Since inception the tailings dam at Kiriburu Iron Mine is very stable and further, regular maintenance of the dam & implementation of the system for clear water reclamation and recycling have been resulted in improving the stability of the dam. ADDITIONAL DETAILS SOUGHT BY EAC IN THE 14th MEETING Page 2 HELD DURING FEBRUARY 26-27, 2020 © 2020 MECON Limited. All rights reserved Amendment in Environmental Clearance Due to Changes in Project Configuration of Kiriburu- Meghahatuburu Iron Ore Mines of SAIL Tailings Pond at Meghahatuburu Iron Ore Mine: The tailings produced from the Meghahatuburu ore beneficiation plant are fed through a pipeline to Rang-Ring Tailings Pond by gravity about 2.4 km. The tailings pond was constructed during 1987 with a catchment area of 405 ha. The site for the tailings pond over Rang – Ring Nalla was selected taking into account of geology & topography of the area and stable base. Considering local geology and soil characteristics, earthen dam was considered suitable. The Rang-Ring Tailings Dam was planned and designed to construct in two stages. In the first phase, the dam height was kept at 23 m (Elevation: 528 m RL) with tailings storage capacity of 2 million cubic metres. It was planned that the dam will be further raised to its ultimate maximum height of 37 m (Elevation: 542 m RL) when it will have an ultimate additional capacity of 9.4 million cubic meters. The salient features of the Rang-Ring Tailings Dam are as follows: Table 1 - Salient features of the Rang-Ring Tailings Dam Parameter 1st Phase 2nd Phase Agency of Design Central Water Commission, - New Delhi Catchment area 405 ha 405 ha Bed level 505 m RL 505 m RL Top of the Dam 23 m height 37 m height (Elevation : 528 m RL) (Elevation : 542 m RL) Length of the dam 474 m 650 m Full tank level 524 m RL 539 m Impervious fill 4,00,000 m3 11,00,000 m3 Capacity of the dam 2.0 million m3 9.4 million m3 (addl.) Presently, the Rang-Ring tailings dam is in 1st phase with a capacity to hold 2 million m3 (4 million tonnes) with dam height of 23 m. A spill channel has been provided to discharge about 16.6 cumecs and stone protection on the bed and sides of spill channel has been provided at the entrance as well as exit. Presently, the tailing pond is partly full and accumulated about 3 million tonnes of tailings. In order to improve stability of the dam, internal bunds have been made within the pond. Except in rainy season, there is no direct overflow through spill channel from the tailings pond, but seepage from the earthen dam exist. Since inception the Rang- Ring tailings dam at Meghahatuburu Iron Mine is very stable except seepage in few occasions, which have been successfully controlled. It can be summarized that the Tailings dams at Kiriburu and Meghahatuburu Iron Ore It can be summarized that the Tailings dams at Kiriburu and Meghahatuburu Iron Ore Mines have been constructed over stable bed rocks and in operation since last 50 yrs and 30 yrs respectively and no sign of failure of these dams was observed till date. The mine project area falls under Seismic Zone – II as per the ISI Seismic Zone Map i.e. it ADDITIONAL DETAILS SOUGHT BY EAC IN THE 14th MEETING Page 3 HELD DURING FEBRUARY 26-27, 2020 © 2020 MECON Limited.