Top Works: Centre Feed Pipe, PF (Pulverised Fuel) pipes,

Transcription

1 Description: Overhaul of Coal Mills feeding Pulverised Fuel to Boilers 1-3 Review Priority L Location: Power House Duration: Contents Component Overview... Page 1 Weights of Individual Components... Page 2 MILL TOP MAINTENANCE TASKS Mill Disassembly - Preparation... Page 2 Mill Disassembly Task Steps... Page 3 Top Works Removal... Page 4 Dome & Mill Body Removal... Page 5 Underbowl Removal... Page 6 Table Removal... Page 7 COAL MILL GEARBOX MAINTENANCE TASKS Gearbox Removal... Page 9 Coal Mill Reassembly... Starts Page 10 Gearbox Reassembly... Page 11 Underbowl Reinstallation... Page 12 Reinstate Top Works... Page 15 Coal Mill Exploded View Illustration... Page 18 Mill Body & Dome Maintenance... Page 19 Underbowl Overhaul... Page 23 Top Works: Centre Feed Pipe, PF (Pulverised Fuel) pipes, Knife-gate Valves, Venturi Air Lines, Orifice Plate, Kidney Spools Dome or Coal Mill Body: Rolls, Roll Doors x 3, Classifier, Deflectors, Cones, Under Bowl: Table or Bowl, Vane Wheel, Scrapers Gearbox Mounting Plinth Knife gate Valves Venturi Air Line Spool Typical Top View of Top Works: Venturi Air Lines & Knife gate Valves Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

2 COMPONENT WEIGHTS 1t= 1,000kg Top Mill Body Assembly t PF Bend (Full length) kg Works & Mill Dome kg PF Discharge Valve kg Mill Body Mill Roll Door t PF Discharge Port kg Scraper Assembly kg Centre Feed Pipe kg Mill Underbowl t Rolls Journal Spring Assembly t Table Mill Table t Gearbox Gearbox Complete... 10t Gearbox Drive Electric Motor t Note Before commencing any work, always check the JHA information and always Take Two Preparation 1. Barricade Area Erect Danger Chain barricade around the complete Mill, at all levels. 2. Clean down Mill Wash down with water, all components & area as required 3. Build (Lower) Scaffolds 3 x side of Gearbox (East, South & West sides - not over electric drive motor) for access to Air Tusk & Bowl mounting bolts 2 x at PA Fan (East & West sides) for access to Expansion Joint Gate Valve to insert spade as a safety measure to prevent Hot Air entry to Mill 4. Build (Upper) Scaffold To access Top Chute & PF bends 5. Air Winch (2 x 3t) installation Inspect & test the operation of the Air Relocate Beam Trolleys from current Hoists. position to Monorail Beams above Mill Fit Hoists with individual air supply & Requires the use of a scissor lift & purposebuilt support stand Inspect condition & check operation of lubricator / regulator (set to psi) Safety harness to be worn whilst in the lifting equipment before using. Caution Scissor Lift Fit Dust Bags over chains Tie the air hoses back away from work area 6. Unit Preparation by Operations Empty Coal Bin & Hopper above the Mill Isolate & perform a final wash down of the Mill 7. EAP Isolation required ( Electrical Access Permit) - for Motor / Gearbox removal Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

3 Top Works / Mill Body / Underbowl Refurbishment Ensure Danger Chain barricade is in place on ALL levels, before commencing. Plus install & secure 2 x Danger Gates at the Mill Body deck level openings. Place all bolts / nuts & small components into orange crates. Constantly maintain a neat and tidy working environment. 8. Blank the 2 x Steam hose flanges at the Underbowl west side. 9. Insert spade at PA Fan Expansion Joint Gate Valve ( if required) A safety measure to prevent Hot Air entry to the Mill if the Knife Valve is bypassing 10. Disconnect & Remove Pyrites Hopper Components: Square-to-Round Spool and Knife Valve on the Pyrites Hopper 11. Disconnect Air Tusk Seal Air pipes & manifold hoses Tusk mounting brackets, may be welded to Underbowl, may require cutting for removal Secure at 3 points to the gridmesh support beams, with 3 x Come-alongs Remove rubber bellows Check internals of Tusk for coal build up. Remove any excessive coal residue 12. Remove Mill Doors 3 x Mill doors (700 kg each) Retract journal stop bolts allowing rolls to sit on table. Remove North door with 2t chain block mounted centrally above Mill and transfer to air winch. South West door and South East doors lifted with air winch ½ tonne com-along is required to control movement after bolts are removed. 13. Remove Rolls 3 x Rolls ( t each) Use triangulation of 3 x 1.5 t Com-a-longs or Chain Blocks through doors to control lift Caution The grid mesh is not rated to hold the weight of this Roll assembly East & West Rolls - lifted via Monorails & Air Hoist Air Hoist rolls to ground level Central North Roll - use chain block fitted to central lug above Coal Mill door, or use mobile crane assistance Lower Rolls to ground level Transport to Main Workshop for further maintenance (Use the correct Carry Cradles) Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

4 14. Install mobile purpose-built yellow platform For access to the Top Works region Use 7t mobile crane for assembly Reinstate decking level handrails as soon as platform is lifted onto deck 15. Electrician required: Disconnect & remove limit switches / probes on Top Works & Dome Top Works Removal Note Mark & note location & alignment of all equipment (See graphic) as component alignment is different in every location. This may assist the correct positioning at reinstallation across the different work crews. Locate this information where it can be found again at time of re-installation When removing these components place them in lay down area, & keep alleyway clear. 16. Disconnect 3 x braided Venturi air lines from Manifold 17. Disconnect air lines and limits from all Knife Valves. Note Collect & place all parts on pallets as they are removed. Maintain a clean and clear work region at all times 18. Install / position chain blocks to support PF Bends & Feeder pipes above Mill Caution Venturi Spool Air Lines Kidney Spool Orifice Plate Mill Dome Knife Valve Note Mills 1B, 2B, 3B and 3C have holes in the strengtheners of the Coal Feeder Chutes for shackles to be fitted (to carry chain blocks). For all other Mills DOUBLE WRAP two slings opposing each other around the very top section of the Centre Feed Pipe to carry the chain blocks, (located above the top expansion joint). Sling & support PF Bends There are many obstructions! Take great care, Safety harness to be worn and attached. Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

5 19. Remove all Top Works components Lower to ground with chain block / air hoists & relocate to lay down area. Ceramic Orifices Short Spools Venturi air lines & Spools Lower Kidney spools Knife Valves Lower Centre Feed Pipe (short) 20. Top Centre Feed Pipe Remove the long Centre Feed pipe using chain block and air hoist 21. Feeder Chute - Bottom Section Review the date the Chute was last replaced With the long Centre Feed pipe removed and using a torch, inspect the internal surfaces for excessive wear. If required, replace the Bottom Section once the Mill Body has been removed and the Main Hopper emptied of any remaining coal. Scaffold platform will need to be modified. Bottom Do NOT fully tighten flange bolts until the long Section of Centre Pipe is reinstalled and lined up with short Feeder Chute Centre Pipe on the top of the Dome 22. PA Fan Duct Support / suspend Ducting (Expansion Joint to be inspected / replaced at a later stage) 23. Strip & Remove Yellow Work Platform Use 7t mobile crane to aid in the removal Reinstate the handrails along the edge of the decking once the lift is completed Place under the Coal Conveyor on the Western side of the Powerhouse Coal Mill _Cut.doc Pyxis Services 14 Jan of Dome & Mill Body Removal (weight 6t) Caution HEAVY LIFTS! Remove entire assembly as one unit (Mill body, top plates, cone and separator) Using both 3t air hoists and special Coal Mill lifting beam. Unbolt Mill Body from the Underbowl Lift & lower to ground, using the 2 x large capacity lifting lugs on the Dome. Reinstate the handrails along the edge of the decking once the lift is completed Transport to the Main Workshop Wash Down bay using the 15t fork lift. (Secure the Body to the forklift to prevent slipping off the forks.) Remove as much coal from the internal surfaces as possible before moving into Main Workshop bay. Note Ensure a spotter is used for this transporting task. 25. Erect hard barricade above Table / Gearbox A fall hazard has now been created and a hard barricade MUST now be erected around the Mill Body opening.

6 THE FOLLOWING STEPS involve HEAVY LIFTING, & Pinch Points. Manual Handling in tight work spaces. Consider posture, position & lifting gear carefully. 26. Remove Vane Wheel segments (6x) Segments are heavy! Unbolt segments from Table. (may require oxy cutting the capscrew heads.) Sling & lift segments with long-travel air Note hoist & long 1t sling for removal Requires two persons, careful manual handling Use Crank handle to manually rotate gearbox to assist in accessing segments 27. Remove Under Bowl (2.2t) Unbolt from Gearbox Fit 4 x (pink) 2t Lifting Lugs (located in Coal Mill Locker) Ensure PA Ducting is clear of Underbowl during lift Lift (via air hoists & special lifting beam) & lower to ground level, sit onto chocks Relocate to Main Workshop by forklift for inspection & refurbishment 28. PA Fan Duct Expansion Joint Inspect / Replace Expansion Joint Main Workshop - Underbowl Refurbishment 29. Inspect / Strip Under Bowl Replace damaged Wear Liners & Plates. If no wear is evident, then items may be reused. If required, Grit blast inside to remove the old refractory Grit blast outside surface & repaint with special High Temp Silver Paint Table Vane Wheel Segments Under Bowl Fins to be replaced 30. Pipes & Connections Ensure all are unblocked and not holed. Replace as required Pipes 31. Replacing Fins Inspect & replace as required Replacement fins must be 10mm thick Positioning & Clearances are critical 32. Inspection Door Fit new 16mm Bisalloy Plate to the Inspection Door, (if required) Refractory to be replaced if new plate is fitted. Leave door unbolted. Inspection Door Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

7 33. Replacing Wall Plate Liners & Skirts Fit new bottom strip below Wall Liners Fit Wall Liners Grind the top strip off the Liners Number & retain strips for refitting Wall Liners after the refractory pour Refractory is not poured until Inspection Door Liner clearances with Vane Wheel are Skirts confirmed back on the Table. Replace worn Bottom Ring Skirts Must sit flush with bottom of Wall Liners Retaining studs must be double nutted. Note Clearance is Crucial - Underbowl Wall Liners Once assembled, the Vane Wheel Outside Diameter should be 1896 mm Clearance to Wall Liners is between 3-6 mm Confirm Wall Liner internal dimension. Must be 1902 mm to 1908 mm diameter Adjustment of Liners may still be required once the Vane segments are fitted to the Table. 34. Centre Feed Pipe Disassembly Top Kidney Note Mark position of all components before removing to Plate ensure alignment & locating into the same position for reassembly Remove from Mill Body Place into purpose-built stand for maintenance work Remove Small Cone Inner Remove 2 x Stopper Angle Irons Deflector Remove Top Kidney Plate Relocate the Stand to the Wash Bay to remove heavy build-up, if required (place forklift fork under bottom of shaft and gently lift. This will allow cleanout of any coal residue) Small 35. Inner Deflector Removal Cone Inner deflector assembly in f Inner deflector assembly components Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

8 36. Outer Deflector Removal Caution Unbolt small counter-sunk hex screws on Outer Deflector & Remove Deflector Ensure correct lifting equipment and methods are used. Dome Removal 37. Separate the Dome / Classifier assembly from the Mill Body Mark the Dome & Body to ensure correct alignment when Note reassembled. Use of a crane required. Mill Body Dome Classifier Cage Inner Cone Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

9 Coal Mill Body Refurbishment & Reassembly Caution DO NOT use Spring Washers on any parts during the rebuild of the Coal Mill The excessive vibration of the Mill during normal operation will cause the bolts to loosen. Note All bolts are to have High Temperature Anti-Seize applied. 38. Mill Body Inspection Use Form Pulverising Coal Mill Wear Liners Internals Inspect to record findings Classifier Cone: Inspect for replacement (SP-10108) 39. Mill Body Liners Major repairs to Body Hard Faced Carbide Liners at Australs Perth. Remove Wear Liner segments Minor repairs may be carried out on any eroded areas, especially at the bottom corners of the 3 x Doors. Table 40. Mill Body Liners - Reassembly Fit new Wear Liners loosely Note Liner types vary (leading/trailing) Ensure correct positioning Ref: Drg. No.110-SP Check bolt is correct size to fit internal slot Install new liners using double nuts Leave loose until body is reinstated onto the Mill Gearbox All the Studs require Double Nuts Inside wall liner Helicoil any damaged threads on the Doors / Flanges / Trunnions etc. Dome Maintenance & Inspections 41. Invert the Dome / Classifier / Cone assembly for refurbishment Inverted Dome/Classifier/ For maintenance of the Classifier Cage & Cone Assembly Inner Cone components, invert the Dome & set on blocks once separated from the Mill Body Lifting & rotating equipment must be Caution done with care, movement controlled at all times. 42. Unbolt Cone and remove all Classifier blades - from Separator top section. Remove Classifier Cage from Dome Mill Body: Hard Face Internal Lining Inside door liner Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

10 43. Dome hard facing should be inspected and sent to Australs Perth for any refurbishment. Tap out all threaded holes and helicoil any damaged threads. 44. Classifier Cage Refurbishment Inspect & refurbish the Classifier Cage. Check for erosion on the rectangular openings Check and replace any worn lower shaft locating brackets Replace Cage onto Dome and Install Classifier Blades Dome with new Classifier Cage & Blades fitted 45. Replace Cone to Classifier Cage The new tack welded Cone should be bolted to the Classifier Cage and then fully welded externally. Once welded, it should be removed and fully welded internally. The Classifier Blades should be installed BEFORE the Cone is refitted to the Cage. When the Cone is refitted, the nuts must be on the outside and tack welded Refurbished Dome Classifier Cage Nuts welded on Inner Deflector Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

11 46. Set the Classifier Blades (See Graphic below) Reference: D110-M & Figure 5, Classifier Vane mechanism, page 36, Bowl Mill Manual, Library Reference Number 123. External position indicators at the Zero position Using a gauge or protractor, set the flats on the classifier blade shaft at 26 to the centreline of the Classifier arm. Check the internal position of the Classifier blade. The flat section of the blade should point to the centre of the mill. 47. Reset the external position indicators to 2⅔ position. This position requires adjustment when the Mill has been returned to service. TOP VIEW Angle Adjustment Arm External top of Dome Classifier Cage Internal Replacement Cone comes in 3 sections & requires welding together Careful Lifting techniques required 48. Lift Dome / Classifier Assembly onto Mill body Note CRITICAL - Ensure Correct Alignment of Dome & Body - Check & realign markings from disassembly. Check round bar halves on the mating flanges Use Hi-Temp Silicone Sealant gasket material Tighten bolts to specified Torque Setting Follow Site Standard Stud Tightening Pattern 49. Install Outer Deflector Ring - Refer to drawing: D110-M Position onto top of the Dome Bolt on the heavy Outer Deflector Ring 50. Centre Feed Pipe Overhaul - Sitting on Stand: Place new Inner Deflector Cone onto stand (if required) Refit original Centre Feed pipe Weld on Stopper Angle Irons Weld on Small Cone at the bottom in exactly the same place as previous Cone External Classifier Blade Position Arm / Indicator, Top of Dome Classifier Blade set to 26 from Angle Adjustment Arm Outer deflector ring Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

12 51. Centre Feed Pipe Reassembly - Refer to Drawing: D110-M Lower the top plate onto the top of the Inner Feed Pipe Install & tighten the cap head screws Locate holes using a podgy bar 52. Locate Assembly onto Mill Body Lift this top plate - Inner Feed Pipe assembly onto the Separator body. Install and tighten all cap head screws for the top plate. Refit Refurbished Underbowl 53. PA Fan Ducting Gasket Install HT Ladder Rope & Hi-Temp Silicone Sealant for gasket material 54. Install Underbowl Onto Gearbox (Weight ~ 2.2t) Transport into Facility & prepare lifting equipment Check / replace any damaged studs on top of Gearbox Use High-Temperature Silicon Sealant Gasket material between Underbowl & Gearbox Lift Underbowl into position on Gearbox Tighten Studs to Specified Torque Value Follow Site Standard Stud Tightening Pattern around entire Underbowl body 55. Connect PA Fan Ducting to Underbowl 56. Install Vane Wheel Segments Use only a matched set off Vane Segments Re-mark the Alignment Letters on top edge of each segment using White Paint (small lettering is stamped on face of each segment) Fit one (1) Vane Wheel segment to Table Manually rotate Gearbox / Table & check clearance around outside circumference. Fit the remaining Segments loosely in position till clearance with Underbowl Wall Liners is confirmed. Grinding of Wall Liner s back spacer length may be required The Clearance is Critical Note Vane Wheel Outside Diameter should be 1896 mm Clearance to Liner is 3mm to 6 mm Wall Liners internal dimension must be 1902 mm as a minimum Once clearance is established, remove one Vane segment, and tighten all other segments into place Check all Wall Liner mounting bolts are tight Rotate Gearbox to align the gap of the removed segment with the PA Ducting Leave this last segment out until after refractory is poured behind Liners (including the Vee plate at the Primary Air entry) Underbowl Wall Liner UNDERBOWL Vane Wheel Segments Table 3 mm 6 mm Clearance Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

13 57. Apply Refractory Reinstate refractory to specification Assist contractor Ensure the Angled Gap is also filled with Refractory 58. Weld Top Strips to Wall Liners Weld strips once Refractory is dry Ensure the small angled gap is also plated over Fit Last Vane Wheel Segment when done Fill cap screw heads with HT Silicon Sealant to prevent dust entry. 59. Install Seal Air Tusk Manifold Install new Expansion Bellows Reinstate the Tusk manifold mounting brackets Fit Tusk to brackets and bolt securely 60. Refit Gridmesh Corners to Upper Deck (if required) NW & NE corners 61. Reinstate Mill Body - rolls or doors not yet fitted Transport Mill assembly from Workshop to Powerhouse with Crane or Forklift Apply Hi-Temp Silicon Sealant for gasket material between Underbowl & Mill Body Crane Mill Body into position over the Underbowl Align, lower & fit mounting bolts Follow Site Standard Stud Tightening Pattern around entire mill body Wall Liner Pour Refractory Into this space Ensure a spotter is used for this transporting task. 62. Tighten Wear Liners - When Body is seated flat & tightened onto Underbowl Insert 10mm Key Steel Spacers under Liners bottom edge Lower Liners onto the spacers & tighten. All retaining bolts shall be double nutted. Remove Key Steel Spacers 20mm Spacer Underbowl Note Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

14 63. Install mobile purpose-built yellow platform For access to the Top Works region Use 7t mobile crane to aid in assembly Reinstate handrails as soon as platform is lifted onto deck 64. Feed Chute Ensure Maintenance & Repairs have been done before commencing on Top Works installation 65. Install REAR knife valves & spools (South side of Mill) Rubber Grease ( stock item) MUST be applied to the rubber sealing rings to prevent clamp damaging Use High Temperature Silicone Sealant for all full faced gasket surfaces Install Kidney Shaped Spools onto Dome Install Short Spools (Differing Number of Holes on Flanges) Fit wear rings to top of short spools Check the Knife Valves will position correctly for Hoses and Wiring Install Knife Gate Valves, ensuring the valve FLOW direction is correct Reinstall the long and short Centre Pipes, ensure connecting collar is squarely aligned. Use Rubber Grease on the Connecting Collar sealing rings Insert HT Silicon Sealant & HT Ladder Rope on the Top Chute flange faces and tighten ALL bolts and studs Venturi Air Line PF Pipes Knife Gate Valves Kidney Spool 66. Install FRONT knife valves & spools (North side of Mill) Repeat the above steps for the Front Knife Gate Valves 67. Reinstall Venturi Spools & Braided Hoses Check markings & ensure placement is the same as pre-overhaul Centre Feed Pipe Centre Feed Pipe Connecting Collar Mill Dome Venturi Spool Short Spool Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

15 68. Replace Ceramic Orifices Install new Ceramic Orifices into the PF pipes The 4 off Orifices are specific to their location, ensure they are positioned on their appropriate PF pipe Rubber Grease ( stock item) MUST be applied to the rubber sealing rings to prevent clamp pinching and damaging 69. Connect Air Lines to Knife Valves 70. Install Knife Valve Limits & Top Probe on Dome Electrician to connect 71. Strip & Remove Yellow Work Platform Use 7t mobile crane to aid in the removal 72. Powerhouse Crew To Pre-Adjust & Lubricate Rolls Install Mill Rolls 73. Rolls weigh ~1.5t each Using Carry Cradle, move the Rolls to Powerhouse Use Air Hoist on Rolls for southern Mill positions Use of Mobile Crane may work for northern position Manoeuvre Rolls into position within the Mill Body Use triangulation of 3 x 1.5t Come-alongs or Chain Blocks through doors onto seat position Caution Gridmesh is not rated to hold the weight of these roll assembly Install Mill Doors Roll in transport cradle 74. Fit back two (southern side) first Fit Northern door last Use GREASE for gasket material (Not Silicone!) Tighten to specified torque setting Follow Standard Stud Tightening Sequence pattern Connect all flexible Air Hoses to Roll Trunnions Connect all stainless steel tubes on Mill Body instrumentation 75. Install Mill Probes 76. Grease Mill Doors & Classifiers 77. Modify ILP on Mill Overhaul for Steam Blinds 78. Reconnect Quenching Steam Blinds 79. Reinstate all remaining Gridmesh & Handrails around Mill Body Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

16 80. Install new Knife Valve on Pyrites Hopper 81. Reinstall Square-to-Round Spool on Pyrites Hopper 82. Ensure PA Fan Expansion Joint & Ducting work is complete 83. Close all inspection doors Fit new gasket material 84. Remove 2 x 3t Air Hoist assemblies 85. Remove all platforms & scaffolds 86. House keep all levels & areas Remove any waste material from area & place in appropriate skip bins on ground level 87. Recalibration of Dampers 88. Replace Bunker Fill Capacity to Logic 89. Remove ILP Perform start-up Mill Roll Adjustment 90. Adjust Classifier Blades Set to base setting of 2½ graduations To be adjusted during start-up procedures Table & Gearbox Refurbishment (Additional Tasks) 91. Gearbox Probes Disconnect & remove 92. Drain Gearbox Oil Removal in 44 Gallon Drums or other approved containers Transport to waste facility 93. Remove corner sections of Grating (x 2) NW & NE corners from deck above Gearbox to lay down yard 94. Remove Air Tusk to lay down yard Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

17 95. Remove Scrapers, Skirt & Seal Cover Fitted below the Table Requires two persons, careful manual handling Remove both Scrapers Remove both Split Skirt Assembly & Inspect for wear or damage Note New Skirt may require holes drilled on the Top Flange. Remove & Inspect Inner Seal Cover for damage or excessive wear on Brass labyrinth Send split covers to Perth for brass labyrinth replacement. 96. Remove Gearbox Lubrication & Cooling Lines Note location & arrangements Collect & store safely for replacement at refit Table Removal 97. Position Cross Over Grating Position crossover grating to gain safe access to Table top. 98. Remove 2 x Top Covers from Centre Shaft Table 99. Extract 2x Dowel Pins from Centre Shaft Pins may need to be drilled & tapped to facilitate removal with a puller THERMAL BURNS RISK WEAR THE CORRECT THERMAL PROTECTIVE EQUIPMENT Cover 1 Cover 2 Table Wear Plates Scraper Skirts Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

18 100. Prepare for Table Removal Weight of table 4t - 5t, depending on condition & previous repairs Table bore is an 008 Interference Fit On The Centre Shaft Required: Personnel - Team of 4 from Hoffman s Engineering + 1 Local 1 bank of 8 LPG bottles 2 banks of 15 Oxygen bottles Special Powerhouse Lifting Beam (using holes F for the Table) Find & re-locate to the work space 200t Hydraulic Ram/ Puller assembly Gas burner shroud heating jig Handle for manual gearbox rotation (in the Coal Mill cupboard) 4 x Correct rated 2t Eye Bolts 2 x 3t Air Hoists Laser Thermometer 101. Install Shroud Jig Under The Table (Minus The Rotating Centre Shaft) Fit gas torches & connect to gas source 102. Table Heating & Removal Insert 3 x Pulling Threaded Rods into Table Table must be heated evenly all round Rotate Constantly during heating Note Water hose the Oxygen Regulators to prevent icing up Optimum temperature differential of 120 C between Table & Shaft (Approx 2 3 hours) When this is reached, fit 4 x 20mm Eye Bolts into edge of Table & secure to Lifting Beam ( Place fire blankets on Table edges) Lifting Beam Table Heating & Transport Jig Oxygen Bottles Torches x 4 LPG Bottles Heating Shroud Tool Locker Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

19 103. Fit Pulling Ram (Only When Table Has Reached Optimum Temperature) Fit 200t Hydraulic Ram/ Puller / Spacers to top of Table Fit fourth Threaded Rod into Table Secure Ram assembly to Lifting Beam Protect hydraulic hoses with fire blankets Operate ram to separate the Table Lift to ground level & place in carry stand Barricade area & allow Table to cool Remove Eye Bolts immediately, before the Table cools, to avoid them becoming frozen in place Gearbox Removal 104. Unbolt Gearbox from mounting plinth (x 4) Use 95mm Hydraulic Torque Wrench & power pack (hired equipment) Caution Pinch points / crush injury possible with this equipment. Follow instructions. Avoid removing studs from mounting plinth Note Gearbox Lift (Weight 10t) Remove 2 x 3t Air Hoists and install 2 x 6t Air Hoists Use special Powerhouse Lifting Beam (using holes E for the Gearbox) Chain around & through Gearbox body (see photos) 2 Stage Lift required: Single lift will not provide adequate clearance of structural steel. Powerhouse Lifting Beam Purpose built Stands of lifting configuration Gearbox Locating Pin on Mount Plate Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

20 Gearbox has a Locating Pin Caution Situated between Gearbox & Plinth. Use caution & a slow Vertical Lift to avoid any damage When the chains have just taken the weight, tap the Plinths with a sledgehammer to shock the Gearbox away from the Plinths (If Plinths do lift, then re-grouting will be required) 105. Lift Gearbox 1 st Lift by wrapping chains thru Gearbox openings, lift & insert purpose-built stands below Gearbox, then lower Gearbox onto them Lower lifting beam until there is 100mm 150mm clearance between the top of the shaft and the underside of the Lifting Beam. Shortening the chains will then provide adequate clearance over structural steel 2 nd Lift will raise Gearbox again & lower onto the stands in the alleyway Transport the Gearbox to the Main Workshop Note Options for transporting: Restrictive space - 20 t mobile crane or 15 t low-mast forklift 106. Remove Grout from under the Base Plate (If required) 107. Careful positioning of the Base Plate is necessary to ensure correct alignment of locating pin / key slot & to ensure plates are level ( If required) 108. Epoxy Grout under the Base Plate (If required) Gearbox Disassembly Gearbox Disassembly In Main Workshop Prior To Despatch Offsite 109. Remove Scraper Plates from top of Gearbox Floor Plates in 4 sections Requires two persons, careful manual handling for plate removal 110. Remove Refractory from top of Gearbox Use hammer & chisel or Jackhammer on Refractory 111. Gearbox to be washed down & then delivered to Warehouse Hofmann to undertake gearbox refurbishment Ensure new input shaft coupling half is supplied to Vendor Note Ensure no oil leaking from Gearbox 112. Electric Motor and Gear Coupling Electrician is required Disconnect electrical cables (new motor to be installed) Install new coupling half onto new motor, ensure the interference fitted hub, is installed as shown Coupling Hub Orientation Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

21 Coal Mill Gearbox / Table Reassembly Gearbox Assembly In Main Workshop After Overhaul 113. Install Refractory to Top of Gearbox Tap out Stud / Bolt Holes Wire buff to remove any rust from Refractory surface Replace any missing 20mm Spacers around bolt holes Check / repair flat bar around the Pyrites Hopper opening Refractory Outer Lip Centre Case 114. Install New Wear Plates Fit wear plates over fresh Refractory Caution There must be NO VOIDS under the plates Plates must be flat & level Ensure edge gaps to allow for expansion 115. Wash Down Coal Mill Area Coal Mill _Cut.doc Pyxis Services 14 Jan of 26 Gearbox Top New Wear Plate Fit temporary handles to the wear plates for ease of installation Check that wear plate bolt holes align with Gearbox threads Assist Contractor on Refractory pour to top of Gearbox Set level between centre case & outer lip Wear Plates 116. Gearbox Plinths / Coupling & Electric Motor Base Preparation Using a wire wheel buffer, thoroughly clean the surfaces of both Gearbox plinths & Motor base. Coat with CRC spray Clean & Lubricate with Never Seez, the 4 off Gearbox hold down studs Place protective plastic sheeting over these areas 117. Lift Gearbox Check coupling hub is correctly installed on the overhauled Gearbox Remove the short centre section of the kick plate on the first deck level 1 st Lift as high as possible by shortening chains to achieve approx 100mm - 150mm between Shaft and underside of Lifting Beam Lower Gearbox onto four (4) purpose built stands & lengthen chains to provide adequate Lifting Beam clearance to place Gearbox onto the plinths 2 nd Lift by slowly lowering Gearbox onto plinths, take care to ensure Gearbox is level and is aligned with the Locating Pin and Keyed Slot Torque down the 4 x Holding Nuts and Lock Nuts to a setting of 6,745 ft lbs Apply Densotape over the Nuts / Studs assemblies 20mm New Refractory Layer

22 118. Setup 2 x 3t Air Hoists & Chain Block Remove the slow 6t air winches and install the faster 3t winches Hang a chain block and 1t sling down from the top feed chute region. This is used by the Contractor to lift the Nitrogen chill shroud Table Installation 119. Position Table onto Rotating / Heating Jig in the alleyway Install heating shroud 120. Prepare for Table lift (Weight 4t) Remove 4 x 20mm Lifting Lugs from edge of table till after table is heated & ready for fitting Special Powerhouse Lifting Beam (using holes F for the Table) 121. Table Refit Requirements: Personnel - Team of 4 from Hoffman s Engineering + 1 Local person assisting 1 bank of 8 LPG bottles 2 bank of 15 Oxygen bottles Fire blankets / heat insulating material Laser Thermometer 160 Litre Liquid Nitrogen to chill Centre Shaft Nitrogen Chill Shroud for Centre Shaft Table transport / heating jig & tools to rotate table Caution Table installation is a critical task. Fitting is subject to very-fine tolerances Getting the correct clearances is vital to avoiding major damage to table & shaft Chill Shroud fitted to Centre Shaft of Gearbox WEAR THE CORRECT THERMAL PROTECTIVE EQUIPMENT THERMAL BURNS RISK!! 122. Heating the Table Table must be heated evenly all round to achieve the desired clearance Rotate CONSTANTLY during heating process (1-1/2 to 2 hours) Use 4 Gas Burner Shroud Heating Jig Water hose the Oxygen Regulators to prevent icing up Note Measure the Table bore diameter before and during heating. The heated bore needs to be 008 larger than the original Centre Shaft diameter. Combined with the shrinking of the Centre Shaft, a 012 Clearance should be obtained. Work to achieve a Clearance as per standard fitting practice Consult experienced personnel 123. Installing Table Once desired Shaft & Table clearances are achieved, locate Table onto Shaft without delay! Fit a stopper plate across the top of the Table bore, to ensure correct positioning Remove the Cooling Shroud from Gearbox Shaft Fit 4 x 20mm Eye Bolts into edge of Table Lift Table into place over Centre Shaft Lower Table promptly and then with extreme care to finally align bore and Shaft Remove Eye Bolts before the Table cools to avoid them becoming frozen in place Allow time to cool Note Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

23 124. Drill Dowel Pins on Shaft (When Table Has Cooled Down Overnight) Drill and Ream the Table to accept the new Dowel Pins Fit heavy duty Cover Plate to Shaft when done. Bend over the 4 x Tab Washers Fit domed Cover Plate and then seal cap screw heads with fully welded cover plates 40 x40 x Refit Air Seal Cover around Shaft Use High-Temperature Silicon Sealant Gasket material 126. Refit Skirts & Scrapers Install Skirt to bottom of Table Boss Install two Scraper Assemblies to the Skirt Rotate Gearbox manually to ensure Scrapers are clear of the Floor Plates Special Gearbox manual rotation crank stored in Coal Mill Locker 127. In a Breakdown situation Gearbox seal is done under a CSEP (when still fitted to Gearbox) Table Base Lay Foam or Rubber Matting on the floor for Personal comfort during task Lubricate & install both Split Oil Seals on the Gearbox Shaft Shaft Photo shows bottom seal, the top seal is fitted upside down in relation to this photo Make-up or contact Powerhouse Tradesmen to acquire special Extractor Tools for Removal of New Seal prior to fitting old Oil Seals Gearbox Reassembly cont 128. New Drive Motor & Gearbox Coupling Check coupling hub is correctly installed on motor Reposition Motor, replacing any shims under mount footings Laser Align coupling Tighten all motor mounting bolts 129. Reconnect Motor - Electrician is required Direction Test motor Install coupling spacer assembly Lubricate coupling with grease Coupling Hub Orientation 130. Reconnect Gearbox Probes 131. Confirm the Drive Coupling has been lubricated 132. Fill Gearbox with Lubrication Oil 3x 209 litre drums, lubrication type as per Refinery Lubrication Standard 133. Remove EAP from Drive Motor 134. Electrical Coal Mill Instrument Calibration Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

24 SQUARE-TO- ROUND DUCT PULVERISED FUEL (PF) BENDS DEFLECTOR REGULATOR LEVERS MILL DOME CLASSIFIER CAGE CLASSIFIER SEPARATOR BLADES UNDERBOWL BODY UNDERBOWL WEAR PLATES CENTRE COAL FEED PIPE PULVERISED FUEL (PF) DELIVERY PIPES KNIFE VALVE KIDNEY SPOOLS UNDERBOWL SKIRTS UNDERBOWL WALL WEAR LINERS Coal Mill _Cut.doc Pyxis Services 14 Jan of 26

25 Trouble Shooting: Problem New Hazards and Identified Safety Issues: Step Hazard Details Control Solutions SWI Relevant to the Following Equipment/Functional Location: Associated SWIs for the Coal Mill Coal Group Shutdown Clear Coal Mill Pyrites Hopper Coal Mill Pulveriser Gearbox Oil Change Overhaul Pulverising Coal Mill Top Works Replacement of Knife Valve Coal Bowl Mill Oil Sample Coal Mill Dam Ring - Vane Wheel Change Coal Mill Cone and Classifier Blade Change Coal Mill Classifier Blade Greasing Coal Mill De-Sand Removal and Repl of Coal Mill Door Coal Roll Mill Door Overhaul Overhaul of Coal Mill Door Greasing Of Coal Mill Door Bowl Mill Coal Rolls Overhaul References Coal Mill _Cut.doc Pyxis Services 14 Jan of Pulverising Coal Mill Roll Replacement Coal Mill Roll Oil Check And Fill Pulverising Coal Mill Roll Adjustment Coal Mill Instrument Rod Outs Replace Coal Mill Under Bowl Components? Coal Mill and Cone Welding Repairs Balancing Coal Feeder Control Coal Group Start Bowl Mill Classifier Blade Replacement Replace Underbowl Scapers in Bowl Mill Coal Mill Dam Ring - Vane Wheel Change Replace Table Segments in Coal Mill Replacing Coal Mill Wear Liners Overhaul Coal Mill Eccentric Bushes D110-SP Classifier Cone (stock item) D110-M Classifier Cage (stock item) D110-M Outer Deflector Ring D110-M Classifier Blades D110-M Centre Feed Pipe Reassembly Bowl Mill Manual Powerhouse Library Reference Number 123 D-110-M Type 1 Mill Underbowl Wall Liner D-110-M Type 2 Mill Underbowl Wall Liner D-110-M Type 3 Mill Underbowl Wall Liner D-110-M Type 4 Mill Underbowl Wall Liner

26 Definitions, Terms and Abbreviations ILP Document Control Issue Lockbox Permit Approval Circulation Role Name Signature Date Document Administrator Coal Mill _Cut.doc Pyxis Services 14 Jan of 26