Longwall Mining- An experience of Longwall mining in Padmavathikhani Chinese LW Project,SCCL by MD.Suresh Kumar

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Padmavathikhani Longwall Project is a typical project of its kind where first longwall face was started in 1996 as per Indo-Chinese Agreement. So far

Padmavathikhani Longwall Project is a typical project of its kind where first longwall face was started in 1996 as per Indo-Chinese Agreement. So far

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  • 1. HISTORY OF CHINESE LONG WALL PROJECT IN SCCL– A case study of PVK LW faces with an attempt to make it economically viable * CH. KRISHNIAH ** M.S.VENKATARAMAIAH *** M.D.SURESH KUMAR * Chief General Manager. Kgm Area ** Addl. General Manager, Project Officer *** Addl. Manager, LW Incharge The Singareni Collieries Company Limited, Kothagudem, A.P. (1995 – 2006)
  • 2. SYNOPSIS PVK-5 Incline of Kothagudem Area is one of the biggest underground mines of SCCL,Khammam district, Andhrapradesh. There are three workable seams namely Queen seam (Topseam) King seam and Bottom seam. The mine was started in the year 1952.Extensivedevelopment and depillaring was made in King seam and bottom seam. A vertical shaft of 212m was sunk in the year 1971/1972 and equipped with winding arrangement. Subsequentlychair lift system was also introduced during 1999, which reduced travelling length. The Mine is not only prestigious one in the company but also in the country as it has beenpioneer in mechanisation and new technology with development of shuttle cars. With bilateralagreement between India and China, two Longwall sets with 4X760 te IFS Powered roofsupports and 2 km long steel card belt supplied by M/s CME China and put them intooperation in the mine at Top seam.Out of that one unit has been transferred to GDK 9 Inc RG IIArea.1. INTRODUCTIONLongwall panels have been prepared in Top seam having ‘F’ grade coal. The King and bottomseams are containing high-grade coal C & B grade, which were worked extensively byconventional board and pillar mining upto 280 m depth. The workings were extended upto400 m, depth by Mechanised development by 811 Model LHD’s and Road headers for makingheadings for introduction of Continuous Miner.So far 11 LW panels have been worked in this seam in middle section having coal and shale ascontact roof of supports except panel No 21 which was worked with sandstone roof as contactroof. The 12th Panel (i.e. panel No 8) is presently working in the mine.2. THE DETAILS OF DIFFERENT PANELS WORKED AND TO BE WORKED IN THE MINELW I unit had worked panels 2, 4, 5A and 5D and unit II had been working panels 3, 5, 5C, 22,1, 1A, 21 and 8. There by LW I & II have produced 19,71,874 Tonnes and 27,75,095 Tonnesrespectively. The performance of Longwall in PVK is given in Annexure I. Top seam Panels 7 9 10 11 12 13 14 Total MT Reserves 5.06 4.14 4.60 3.52 3.50 3.54 6.94 31.33 King seam Panels 8 9 10 11 12 13 14 1.6 History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 2
  • 3. As per the feasibility report there were 26 and 14 panels proposed having reserves of 15.4 MTe and 9.63 MTe in Top and King seam respectively.Out of 26 panels in Top seam, 11 have been completed. The balance 14 panels have beenreduced to 7 due to the following reasons, 120-m face length as proposed in FR was re-drawn to 150 m. Change in fault position and its throw, as per latest geological Information. Whereas in the Virgin King seam 14 panels have been projected as per ‘FR’. However 7 panels are available below the panels in Top seam. Finally, the following are LW panels available for extraction in the Mine. 3. VIRGIN PROPERTY ON THE NORTH SIDE AND DIP SIDE OF TELLAVAGU A seasonal Nalla known as ‘Tellavagu’ passing across this area where it needs further planning.( Ref Annexure II ).No panels have been projected in Top seam or king seam in this area in the original FR, Hence detailed geological studies are required. Possibility of addition to this reserve in the North side property is 1.5 Mt in the Top seam and 1.4 M t in the King seam. Proper technology for extracting reserves of1.5 M t in Top seam and 1.4 M t in King seam is to be projected.4. DEVELOPMENT AND EXTRACTION OF KINGSEAMDip workings in the seam have not progressed for nearly 15 years, where the thickness of theseam has reduced from 9 m to 5.5 m. The condition of the seam can be ascertained by actualdrivage of galleries. Present Longwall equipment is designed for 3.2 m height of extraction inTop seam. It is not suitable for working King seam. Hence Continuous miner is a betteralternative than Longwall because of flexibility and to extract upto 4.5 m.(Refer Annexure III )5. STRATA MONITORINGAll the conditions laid down in the permissions for extraction of long all panel No. 21 are beingcomplied with. The details of instrumentation are given below: History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 3
  • 4. (a) Monitoring at the Long wall face: i Individual leg pressure With the help of pressure gauges fixed in each leg of the support survey in three shifts ii Continuous pressure chart C-25[FD], C-40[RD], C-50[RD], C-60[RD], C-75[FD] recorder fixed in five legs Fixed at mid face behind at certain a distance iii Remote convergence from the installation chamber and monitoring used to be done. The indicator(RCI) maximum convergene occurred and the collapse took place.. iv Face convergence At appropriate locations by Telescopic convergence rod(b) Monitoring in the Gate Roads: i. Convergence measurement by at an interval of 10m in TG and MG Telescopic Convergence Rod. at an interval of 5m between 30 to 70m in MG at an interval of 5m between 20 to 60m in TG ii. Mechanical type load cells At an interval of 10m in TG and MG iii Tell tale extensometer At 40m in TG and 60m in MG(c) Additional Monitoring from Surface Multi Point Borehole Extensometer (MPBEx) was installed from surface in the boreholeA/336 located at 30m from the installation chamber. Two anchors were fixed at 40m and 50mabove the roof of the working section of top seam. This is to understand the caving behaviorof the upper strata under stone roof conditions. Two multi point bore hole extensometers with3 anchors were installed from surface to monitor the effect of extraction in long wall panel No21 over the standing pillars of 5B incline. The details of the same are given in Annexure V. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 4
  • 5. 6. Health Monitoring of Power Supports and Hydraulic System1. The leg circuit and the components are being monitoring in every shift round the clock during working of panels by observing the pressure readings during every cycle of cutting. The faulty circuits, damaged hoses, O rings , AE rings, circuit Bypasses, leakages are being rectified immediately.2. The condition of NRVs, Bleed valves, Isolation blocks and Control blocks are critically assessed through static test and were repaired & replaced immediately.3. Static tests are conducted frequently for 8 hrs, 24 hrs during by stopping the face and during idle time with powerpack shut down.4. During the past 10 years the following have been done • One set of NRVs – replaced by OEM. • One set of Bleed valves - replaced by OEM. • 50 % of the Line isolating valves – replaced by OEM. • 50 % of the Control blocks – replaced by OEM. • 25 % of the Control blocks – replaced by Non OEM.7. EXPERIENCE OF WORKING LONGWALL PANELS7.1. Experience of working panel no.4After completion of targeted guaranteed output by Chinese people in panel no.2, the panelno.4 was duly operated by the PVK team of workmen, technicians and officers. People havegained Operational efficiency in the short period and produced 11,315 Te ( 19cuts )per day asthe heighest one day out put record in Asia on 25-03-97.7.2. Dipping panelIn Panel No.5A, which was worked prior to panel No.5C, the seam was dipping in bye. Eventhough knowing the above seam behavior, the gate roads were planned to drive straight. As aresult the gate roads started dipping in bye from 300m on ward. Rest of 260 m drivage hasgone with dipping in bye only. Maximum dipping near the gate road during working of thepanel is 1 in 6. Lot of water accumulation problem in MG junction was faced. Pumping was themajor task both in development of gate roadways by Road headers and while retreating also.The water accumulation at Maingate was pumped out with 2 nos. of 40 HP, 250 GPM pumpsmounted over trolleys coupled to switch train. In addition to that one slurry pump used topump out the water from entering into BSL tailed portion. All these three pumps were used tobe operated round the clock. And the panel was completed by achieving the target. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 5
  • 6. 7.3. Negotiation of deviation Panel No.5CIn panel no.5C, the same behavior was ascertained with the help of ‘STRATUM CONTOURS’and it showed that the seam was dipping ‘inbye’. After drivage of 500 m the gate roadwaysstarted dipping inbye. The practical difficulties faced in panel no.5A forced to think of analternative way to deal with the water problem without pumping. Hence the gate roadwayswere planned to deviate with an angle angle of 22.5 degrees. With the deviation ofgateroadways 212 m of extra length was gained. There fore one more Belt–gear head 150kwinstalled at deviation point i.e. 185 m form the face. The layout of panel no 5c and the methodof ‘Face swing’ at the point of Gateroadway deviation is given in Annexure VI.7.3.1. Supporting at deviation in main gateTo enable the equipment i.e. BSL, AFC and chock shields to negotiate the deviation the galleryat 205m in MG was widened upto 7m. The roof was supported by cable bolting at the widenedzone and for a distance of 20m on either side of the deviation point i.e. 205m.When the facehad reached within 60m of the widened portion OC props were erected at 1m interval. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 6
  • 7. 7.3.2. Sequence of operations♦ Face cutting was done with normal method upto 142.0 m where the 150 kW belt became ‘Zero’ position i.e. there is no provision of skid advance.♦ Face was progressed for 10.5 m by reducing the length of BSL from 42 m to 32.5 m by removing 7 Nos line pans. Another 8.5-m face retreat was done by reducing the length of skid.♦ Then the 150 kw Gear head was dismantled and removed the skid was reconstructed and aligned to the 2 x 200 kW I st Gate belt.♦ BSL discharge unit was dismantled and assembled over the skid and all removed Linepans were reconstructed to the Normal position.♦ Hence the face was retreated by crossing the deviation point successfully.7.4. Negotiation 3.0 m throw fault in panel no.22There was an up throw fault at 70 m from the face in main gate traversing from MG to C-30.Roof collapse took place in the Gate road while approaching the fault. False roofing done withtwo stage girders and the face retreated without any major problem.7.5. Experience of working shallow depth panels 1 & 1A♦ Depth of panel No.1 was shallow i.e. 48 m to 85 m and it was lying over King seam goaf.♦ It was studied and suggested that the panel was to be split into such panels (1 & 1A) having 6-face width each.♦ 43 supports were installed in each face.♦ Average daily production was 1463 Te and 1654 Te including face transfer period in panel 1 & 1A respectively.♦ Maximum subsidence was 2.60 mts.♦ Sincere effort was put for strata control to avoid any mass collapse and pot holing.♦ Multi point Bore hole extensometer was utilised assess caving of different rock beds, details of which is given in Annexure V.♦ Heighest output of 5,610 Te / day achieved by making 34 Cuts /day (19.1 m progress) on19-09-03 in Panel 1A.7.6 Experience of working Panel 21 with Sand stone roof♦ Development of the panel has been done partially in sandstone and partially in coal roof due to thinning of the seam.♦ There was no experience of working longwall under stone roof in this mine.♦ An attempt was made to work with the same equipment and panel 21 has been completed successfully. The experiences gained are summarized. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 7
  • 8. For the first time panel No.21 was worked with sand stone roof as contact roof for 360 m and completed with coal roof in remaining6o m. Unlike other panels intensity of loading and leg closure were more. Both rear legs and front legs were equally during periodic weightings. Induced blasting was done from underground where there was goaf hang of immediate sand stone roof. Much importance was given to hydraulic run of powered supports. Periodic weightings were reported at 10 –12 m intervals against 15- 20 m of coal roof. Induced blasting was in practice by drill of 3 m shot hole between the two chocks near rear legs which avoided long over hang immediate sandstone beds.(details of which is given in annexure VII.7.7 Experience of working panel No.8♦ This is the first panel being worked over virgin king seam and below No.1 seam workings & goaf of 5B Incline.♦ All the future panels will be worked below No.1 seam only. This has attracted lot of regulations and permission from DGMS issued with a number of condition♦ The tailgate was advanced the Maingate by 58.0 m to prove an upthrow fault.♦ The face was started with 58.0 m staggering between MG and TG with an increased face length of 166.0 m (against 150.0 m).♦ Face was retreated with 1:3 ratio i.e. , 1 cut to MG and 3 cuts to TG to reduce the staggering by 20.0 m and Face length to 150.0 m (Ref Annexure VII ).8. SALVAGING AND FACE TRANSFER♦ Usually Salving chamber is prepared by introducing wire mesh in the face from 12th m from the face stop line.♦ A salvage rise is driven for about 23.0 m for installation of 40 HP Direct haulage and making GMT curves.♦ After dismantling and evacuating shearer and AFC pans,the supports are turned, marched and loaded onto la platform car (Chinese trolley ) supplied by CME using Ramp and transported to New site.♦ Brake car is attached to Chinese trolleys, which has hydraulic brakes with over speed tripping Mechanism.9. SAFETY STATUS OF PVK LONGWALLFrom the inception of LW mechanisation in the mine, Only few serious accidents andreportable injuries occurred in the LW district during last 10 years due to the following causes bursting of houses snapping and hitting of broken chain links History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 8
  • 9. fall of objects fall of coal Accidents in Longwall faceYear 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 TotalSerious 1 ------ ------- 3 ------ 1 ------ 4 1 8 4 22Reportable 52 46 59 80 57 37 24 29 19 8 9 420 10. THE VARIOUS PROBLEMS ENCOUNTERED A review of working of 12 Longwall panels in the mine shows the following major problems: 10.1. Quality of coal As per the FR the grade of coal produced was “ F “ grade. It was envisaged to blend top seam with lower king seam. Longwall in king seam was to be commenced in the year 2002.Sequencing of Longwall panels in top seam and king seams were planned accordingly. Due to delay in development of king seam, two Long walls were continued in top seam. Quality and marketing of increased quality of “ F “ grade coal was a serious problem in 2001. Hence a decision was taken to shift one long wall unit from PVK to GDK.9 Inc. 10.1.1 Steps taken for improvement of quality ♦ By changing the section by taking 0.6 m of coal. ♦ By drilling additional boreholes for ascertaining quality. ♦ By changing the section in Longwall as per the quality. ♦ Adding king seam coal by introducing LHDs. ♦ Further with the introduction of Continuous miner in the the mine, which will produce 0.8 million Tonnes of “D“ grade coal with which overall quantity of coal can be improved. 10.2. Problems of equipment 10.2.1 Shearer The various components of shearer are given below: ♦ The major problems faced in shearer are breakdowns of the ranging arm, gearbox and pump boxes. ♦ The OEM ranging arms were failing frequently due to the poor metallurgical composition. Hence new ranging arms were developed at APHEML and their performances are satisfactory. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 9
  • 10. ♦ Failure of gear head boxes mainly at ranging arm shaft bearing houses. They were reconditioned at APHEML several times. Presently Eichoff gearboxes aligned with CME shearer and put into service. Parts of shearer Qnty Remarks Parts of shearer Qnty Remarks Gear Head gear box 2 Eichoff Connection Box 1 CME Boost Haulage 1 CME Under Frame 1 CME Electric Motors 2 CME Cable Handle 1 indigenous Ranging Arm 2 APHMEL Cables 1 set indigenous Cutter Drum 2 Hydra tools UK Picks & Holders 1 set imported (Hyd) Connection Box 1 CME Main Pump 1 Roxroth♦ Indigenously made shearer track shoe, Sprocket assemblies have failed many times in panel no.8 where the Face dip gradient is 1 in 4 to 1 in 6.♦ Due to non-supply of pumps from CME, China, it was decided to convert Eichoff for which conversion kit has been ordered which is still in experimental stage.10.2.2. Armoured face conveyor10.2.2(A). AFC gear boxes and motors♦ There were continuous failures of AFC gearboxes and motors because of their bulkiness and design features.♦ Because of poor quality design of oil seal arrangement at the output♦ Shaft, the slush enter into the gearboxes when working the Longwall panels in wet conditions damaging them.♦ Recently, decision has been taken to convert to gearbox of Gullick Dobson make, which has been released from VK 7 Incline. These gearboxes have been suited to AFC of PVK and presently working satisfactorily with 2x150 kw Morley motors.♦ However, these need replacement since those gearboxes and motors are old.10.2.2(B). Pans,etc♦ The OEM Pans were working satisfactorily except allowable wear and tear in course of time.♦ The AFC pans were not imported from china and hence developed indigenously by APHMEL, Placebo and Jaya Bharat.♦ They have not given sufficient life i.e, 2 Mte. All the pans have given life of 0.7 to 0.8 MTe only. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 10
  • 11. ♦ The various components of AFC including indigenous items are tabulated below Parts of AFC Qnty Remarks Parts of AFC Qnty Remarks Drive Frame 2 Modified ASL Chain Connectors 30 Relock Gear Box 2 Gullick – Dobson Line Pans 83 PLACEBO Motors 2 150 kW Morley Inspection Pans 17 JBE Sprockets 2 Coomer fabric Special Pans 6 PLACEBO JBE Chain 1 set Hindustan Parsons Track Pans 200 JBE Flight bar 300 APHMEL Fluid Couplings 2 Voith E-bolts 300 APHMEL♦ The line pans purchased from M/s Placebo have not given enough results in Panel.21 and Panel.8.The Pan connecting part between pan to support’s front relay bar portion was breaking. Hence, all the pans were removed by stopping the face for 10 days in Panel No.21 and send for repair and reinstalled in the face.♦ The various failures are :- The welded portion of Sigma, Ramp plate used to fail and break. The flowers, which are welded at the top of the pans to retain the Track bar, got failed at welding portion where shearer cannot pass. The Track bars, over which the shearer haulage sprocket move, supplied by M/s JBE, were breaking regularly. Because AFC Ramp plate was not finished with a blade angle to scrap the coal AFC always travel over the loose muck which needs heavy cleaning work infront of AFC and Supports.10.2.3 BSL &Crusher The various Components of BSL & Crusher and are tabulated below: Parts of BSL Qnty Remarks Parts of BSL Qnty Remarks Drive Frame 1 CME Ram pan 1 placebo Gearbox 1 CME Special pans 2 placebo Motors 1 CME Short Pans 1 placebo-JBE Sprocket 1 Coomer Fluid Coupling 1 Voith Chain 80 HP-Relock Blind shaft 1 CME History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 11
  • 12. Flight bar 160 HP-APHMEL Tail end Frame 1 placebo E-bolts 160 HP-APHMEL Sprocket assembly 1 Coomer Chain Connectors 10 Relock CRUSHER 1 CME10.2.4 Gate belt♦ M/s CME provided 2x200kw-belt conveyor, which is more than the requirement of existing roadways.♦ When it was attempted to run with single motor, the belt started slipping as♦ Tandem gears were not provided in the design.♦ Hence, 2x200 kW drive unit was converted into 1x200 kw APHMEL, which was introduced in present Longwall panel No.8, which is working satisfactorily.10.2.5 Power SupportsThe various Components of Power supports and the performance are tabulated below: Descrip- Legs Adv. Linear Bleed Leg Side Side Exten Artcl -tion Ram control valves NRV’S shield algnt Rams Conp valves Rams Ram Ram CME 343 9 73 412 412 56 9 8 192 JBE 59 4 14 106 14 Salzgitter 10 20 26 18 APHML 74 Jessop 26 TOTAL 412 103 103 412 412 56 23 158 26♦ The Salzgitter and Jaya Bharat leg assemblies have failed in Panel No.21 during Periodic Weighting.10.3 Insufficient geological informationPresences of faults were not projected, which resulted in undulations in drivage of gateroadways & roof falls. In such places, development & extraction got sufficiently delayed dueto floor re-grading and heavy roof supporting particularly in panels 22,21 and 8.20 Boreholeswere drilled additionally in the virgin top seam and king seam to ascertain the quality andgeological disturbances. Some deviations were observed which are given below. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 12
  • 13. Fault No. As per FR Revised F 8 North side 2.0 m throw 6.5 m proved F 10 North side 5.0 m throw NIL F 11 34.0 m throw 5 – 10 m and shifted to south side F5 Not existing Exist with throw 65.0 m F 16 Not existing Exist with throw 20.0 m10.4. Ventilation problems♦ Planning of ventilation as per FR is not sufficient because of following reasons. Large fire areas. High pressure differences. Working at below 300-m depth.♦ Detailed ventilation re- organization planned in 2001 was implemented and resulted in reduction of ventilation in dip side.♦ A new shaft is being sunk connected to both Top seam and King seam which increased the Quantity of air.♦ Recommendations of Prof.DC Panigrahi are under implementation.♦ Booster fans may be required.♦ Conversion of 5 shafts as return11. REFURBISHING OF LONGWALL EQUIPMENTS♦ The Longwall equipment in the mine have completed 10 years service and the Power Supports have completed 7,658 No.s of cycles which needs to be refurbished to continue to work the future panels. So as to produce atleast 0.5 M Te per annum.♦ The balance cycles available for Powered roof Supports can work only 1 ½ panels. Hence the powered supports need to undergo ‘Life Cycle test’after refurbishment to get life extension from DGMS.♦ SCCL management held discussions with representatives of OEM to take up the job of total refurbishment of equipment.♦ Performance guarantee after refurbishment was acceptable to OEM likely to take responsibility to get approval from DGMS for 5000 cycles after testing the Powered roof Supports for 6000 cycles.♦ Based on the experience of working of different Longwall panels in the mine, the success or failures with regard to operation and equipment, SCCL is preparing for overall repair and refurbishment of Power roof supports.♦ Modifications, additions, re-introduction of some of the failed parts of OEM Standard and procurement of some new items are being thought of (Refer Annexure X ) History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 13
  • 14. 12. CONCLUSIONS♦ Though the mine was not exclusively planned for Longwall technology, Padamavathi Khani Longwall project has been introduced and completed its 10 years service.♦ 12 Longwall panels have been completed by overcoming different Mining, equipments, Quality, Geological problems.♦ 10 years of LW Operations in the mine ,brought out number of experienced officers ,supervisors and team of technicians and work men.♦ Panels have been formed and extracted right from the out crop and upto 300 m depth in panel No.8 with different walking distances.♦ Experiences gained in the deviation panel (P-5C), Shallow depth panel (P-1 & 1A) and stone roof panels (P-21) were markable one.♦ Strata monitoring studies are being conducted by Mine Management sincerely and the health of supports are being monitored and maintained efficiently. Withthat, all these panels have been worked without any major strata control problems.♦ This is the only project having worked all panels with 150 m face length (except P No 1 & 1A) and planned to continue to work with the same.♦ Longwall production have crossed 1.1 M Te in the year of 1996-97.♦ Longwall production slowly reduced to 0.3 to 0.4 M Te in the last five years due to ageing of equipments and indegenisation.♦ At this end, new strategy has to be formulated to reconstruct the PVK Longwall by refurbishing the equipment and by taking up necessary repairs and modifications for gainful development to extract the further LW panels. So as to make the perfect economically viable.Acknowledgements:The authors expressed their gratitude to the management S.C.Co.Ltd.,for giving permissionto publish the paper. The views expressed in this paper are of their own and not belonging tothe organisation in which they are working.References:1. Report on “Numerical modeling & Strata and support behavior investigations at panel no.21 PVK-5 Incline ”, Dec 04.2. Sarkar SK (1998 ) “ Mechanized Longwall Mining –The Indian Experiences ”3. Dr. Samir Kumar Das (2004), “ Design of Powered supports for Longwall faces” In house short term course for Mining Executives,4. Venkata Ramaiah M.S and Suresh Kumar M.D.,(2004) “Experience of Strata monitoring studies in shallow depth longwall extraction by caving in panel no.1A & 1 of PVK –5 Incline” 3rd National seminar on rock excavation techniques at Nagapur organised by The Indian Mining and Engineering Journal Bhubaneswar chapter. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 14
  • 15. 5. Suresh Kumar M.D.,and U.Shiva shinkar (2006) “Need for working Longwall under hard roof in future under ground mining–An experience of negotiating main weighting in sandstone roof “-Workshop on future of underground coal mining in India Mechanised board&pillar or longwall”organised by JMMF.Kolkata 6. “Compendium on experiences of Longwall Mining Technology"by SCCL. 7. Venkata Ramaiah and Suresh Kumar M.D.,( 2005 ) “ An experience of loading pattern with Sandstone roof in Longwall panel No.21 of Padavathi Khani No.5 Incline – National Storming session on Mechanisation of Underground Coal Mines Challenges and Technical options. Annexure I PERFORMANCE OF LONGWALL PANELS P No.2 P No. 3 P No.4 P No..5 P No.5C P No.22 P No.1A P No.1 P No.21Particulars 660x150 675x150 675x150 830x150 730x150 770x150 520x61.9 500x61.5 420x150Panel size (m) 59/112 76/128 96/141 113/158 155/184 174/203 54/96 48/85 206/239Depth (Mi/Max) 21.8.96 1.7.96 11.11.96 28.7.97 05.03.99 01.06.01 10.07.03 03.02.04 07.08.04Dt of COMCN 2.11.96 29.7.97 18.8.98 24.2.99 16.12.00 04.02.04 12.11.03 12.08.04Date of sealingRear Crumble 66.50 80.65 81.85 61.90 76.75 50.3 98.0 80.0 40.6etreat (m) 10164 12420 12605 9532 11820 7740 6749 5300 6957Area.exposed *m2Max.convergence 71 92 92 110 40 44 15 6 28Tail gate (mm) 15 52 78 83 46 40 16 18 20Main gate (mm) 2.51 1.93 1.88 2.192 0.68 0.945 1.62 2.37 0.140Mx.Subsidnce*m 1.33:1 1.17:1 1.06:1 0.94:1 0.81:1 0.64:1 0.645:1 0.73:1 1:1.50Width/Depth*rtioFrqncy of P.W - - - 15- 18m 18-20m 15-20m 18-25m 15-20m 8-12m 576829 534422 524670 602190 512117 542097 141281 138033 66200Total Prodtn*Te 3354 3147 2478 1946 1032 936 1453 1680 1310Prodction/Day*Te 195 241 322 439 346 740 118 101 248No.Working days 1100 1152 1125 1492 1326 1403 925 786No.of Cycles Panel No.8 is under extraction. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 15
  • 16. Annexure IV STRATA MONITORING PLAN Long Wall Panel No. 8Tail Gate G O A FMain GateConvergence Station MPBExLoad cellTell Tale ExtensometerStress cellLeg pressure GuageContinuous Pressure RecorderStrain Guages History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 16
  • 17. Annexure V MULTI POINT BOREHOLE EXTENSOMETER CAVING OF THE STRATA WITH RESPECT TO FACE PROGRESS sen rs so SURFACEs oil-2. 7mYelowSST l8mLight Brown A1-15mS ST-7m 36m A2-26mHard BrownSST-14m 25m A3-37.5mGrey 13.5mSST-17m A4-45m 6mShal Coal 3m y 68. 0m 80. 0m 141m Face progress Anchor1 Anc ho r2 Anc ho r3 Ancho r4 R emarks 68m Det 3.78mm 4.1mm 0.8mm 80m Det 4.10mm 0.8mm MAIN FALL 141m Det 1.02mm M d ax ilation in anchor 4 is 1.8mmwh the face w at 180m from installation chamb and th land en as er e w su as bsided after that. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 17
  • 18. Annexure VI FACE SWING IN DEVIATION PANEL No.5C Annexure VIFACE SWING IN DEVIATION PANEL No.5CHistory of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 18
  • 19. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 19
  • 20. Annexure VIII FACE STAGGERING IN PANEL No.8 R E D U C IN G T H E F A C E L E N G T H fro m 1 6 6 m t o 1 5 0 m P A N EL N O 8 150m 1 5 0 *4 2 0 m 166m c u t t i n g 1 :3 ra t i o m g t o t g A t m g p ro g o f 8 9 . 0 m a n d t g p ro g 1 2 7 . 4 0 m fa c e le n g t h w a s re d u c e d t o 1 5 0 m Annexure IX THE PROPOSED REFURBISHING OF OLD EQUIPMENTS1. Shearer : New or totally refurbished preferrably with 0.85 m web2. AFC : New pans New drive units with chain tension arrangement side Discharge.3. Supports : Replacement of existing rams with heavy duty advancing • Rams with stroke length of 0.85 m. • Advancing ram – mounting bracket • Repairs to side shields ( top & side ) • Complete hosings • New linear control valve with filters ( 100 sets ) • New isolation valves with filters ( 100 sets ) • Replacing existing mechanical type yield valves. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 20
  • 21. • Replacing existing articulated canopy Rotary rams of 684KN capacity Rams to bear tip load. • Replacing damaged walkway plates assembly. • Re-introduction of side alignment rams with metal base. • Replacing all damaged extension canopies. • Provision of heavy duty anti-topple rams to avoid support tilting gates.4. B.S.L : New pans with chains.5. Skid : Replacing existing 5 Nos. of independent sections by single /double unit of length 15 m.6. Cables : New cables with increased length by 50 m to avoid Frequent switch train shifting.7. Communications : Modify complete water proof lock out and amplifier.8. O C Props : 40 T capacity – 120 Nos.9. Face Transfer : Suitable face transporters or • 60 HP Endless haulers for chock shield transport • New GMTS with rams of adequate breaking capacity –6 Nos. • Light weight support lifting and unloading stations • Face trolleys-2 Nos. for chock shield transport in the face.10. Meshing & boltingduring Salvaging : One hydraulic bolter utilizing the face power pack for drilling operation in the face. History of Chinese Long wall Project in SCCL – Case Study of PVK LW faces Page 21