Worlds highest rated shields design and installation

Transcription

1 Worlds highest rated shields design and installation Ismet Canbulat OUTLINE Introduction to Moranbah North Mine Geotechnical requirements Design phase Installation phase 1

2 ACKNOWLEDGEMENTS Bruce Robertson AMC Consultants Terry Medhurst Johan Laubscher Anglo American MORANBAH NORTH MINE Current and unapproved future workings 2

3 ROOF AND FLOOR LITHOLOGY ROOF AND FLOOR LITHOLOGY 3

4 HISTORICAL PERSPECTIVE Joy 980 tonne PRS were specified and purchased for 8 blocks 4 Southern Blocks (LW101 to 104); and Note: also these were much shorter blocks than subsequently adopted 4 short Northern Blocks (LW 201 to 204) Equated with about 30,000 cycles Joy tendered 8 design options with increasing Factors of Safety and capacity MNC elected to purchase one to suit the shallow mine reserves Plan seems to have been to purchase another set of PRS (and learn from initial installation) HISTORICAL PERSPECTIVE The mine plan requires recognition and an approach to jumping around faulted and bad ground Leads to more longwall face moves (and subsequent lost production) Plan was developed for Walk Off and Walk On twin faces by using existing spares (AFC, BSL and Shearer) New face to arrive for LW108 The aim was to reduce 4+ week longwall moves to 1 week or less Inadequate support capacity has become an issue 4

5 HISTORICAL PERSPECTIVE Ongoing Engineering problems with existing 980t Leg failures due to PRS twisting and leg side loads The design Fix seems to have worked no similar failures 980t PRS have increased to 1,006t/1,034t Structures are being subjected to greater loads than original design/testing Distracts significant resources from day-to-day basics 300m face extension requirements (with 1,200t and mixed 980t/1,033t PRS fully procured Many other issues ranging from niggling to major DA ram lugs (14 left to change) HISTORICAL PERSPECTIVE Ongoing Engineering problems with existing 980t Increasing risk of fatigue induced PRS structural failure/s No spare supports (post-300m face) to effect any refurbishment program 5

6 HISTORICAL PERSPECTIVE Ongoing Engineering efforts to address problems with existing 980t PRS recent 1,200t purchase 1,200t PRS seem to have addressed some earlier shortcomings Increased absolute capacity (1,200t vs. 980t) Increased (pre-cut) support density at yield (125t/m 2 vs. 105t/m 2 ) Improved canopy ratio (2.3:1 vs. 2.65:1) Side shield performance improved (spillage reduces hose failures and steering benefits) Solenoids operating on low pressure (250bar) Hose routing and cylinder design changes (e.g. Sprag hose porting) HISTORICAL PERSPECTIVE Ongoing Operational problems with existing 980t PRS Difficult Geology and Geotechnical in Goonyella Middle Seam Cutting height reductions trialled to improve control Inadequate rating/performance of PRS Operational experience with 1,200t shields 1,200 tonne PRS purchased for 300m Face extension Improved stability Regularly on yield Impact on overall face is still uncertain 6

7 GEOTECHNICAL CONSIDERATIONS What do we require to control caving? Past performance: Almost always on yield Lose control of the roof when >40-50mm of convergence When we get cavities we lose the ability to fully set shields (however, is this chicken or the egg!) Joy S-curves Aim for a Support that is in yield less than 5-10% of the time Joy unable to replicate S-curve data for MNC because of significant time existing Supports are on yield Leg reliability and maintenance issues leading to lower effective density Essential to have adequate set/yield load and stability under yield GEOTECHNICAL CONSIDERATIONS What do we require to control caving? Process used for determining capacity Previously, database approach find similar expected conditions and estimate relative success/changes Ask the OEMs (Joy/DBT) Used to have their own experts to review all the available information No longer interested due to Fitness for Purpose legal arguments Modelling: Ground reaction curves FE Analysis Expert opinions: Callan/Truman Medhurst Frith In-house analysis (BCO and site) 7

8 GEOTECHNICAL CONSIDERATIONS GEOTECHNICAL CONSIDERATIONS 120 Start Posi Set Posi Set Yield pressure % Cumulative % of Time This portion not available, due to being in yield Support Pressure (bar) Ideal Rating Over rated Under rated Very under rated Pressure at Yield 8

9 GROUND RESPONSE CURVE STRATA / SUPPORT CHARACTERISTICS IN EARLY PANELS 9

10 NUMERICAL 300 m MNC 980 tonne 1.75m wide at 4.5m cut MNC 1,080 tonne MNC 1,215 tonne MNC 1,350 tonne (= 1, m wide) NUMERICAL 350 m MNC 980 tonne 1.75m wide at 4.5m cut MNC 1,080 tonne MNC 1,215 tonne MNC 1,350 tonne (= 1, m wide) 10

11 1,500t, 2m WIDE ROOF SUPPORTS at 300 and 350m 1,750t, 2m WIDE ROOF SUPPORTS at 300 and 350m 11

12 ESTIMATED ROOF CONVERGENCE FOR VARIOUS SUPPORT CAPACITY ROOF CONVERGENCE 12

13 INSTALLATION BRIEF HISTORY Feasibility Study done in 2006 and concluded that: To mine deeper panels - require 2m wide x 1750t rated Powered Roof Supports Project approved in April 2007 Contract awarded to Joy Mining Machinery to supply: 151 x PRS (2050mm wide by 1750t rated, 135t/m 2 ) 2 x Armoured Face Conveyor 2 x Shearer Contract awarded to Industria Mining Equipment to supply: 5 x Carriers 2 x Dozers 2 x Retrievers Mini-build at site Rear walkway 13

14 PLANNING Overlapped engineering dimensions of equipment with mine design to determine:- Required height and width of installation face Identify possible height / width issues with proposed Transport Route from Surface to Installation Face Necessary road works to accommodate size and weight of loads (Concreting of critical areas) Relocation of pipes, cables, fire hydrants, etc in the Mains to minimise damage Ventilation restrictions Installation face Transport route (size of loads in roadway) RISK ASSESSMENTS Conducted 18 RA s on Transportation, Installation and Commissioning of complete Longwall system Tracked action completion in SiteSafe Required Safe Work Guideline reviews 14

15 RISK ASSESSMENTS Industrea Mining Equipment supplier of Carriers, Dozers and Retrievers Trials conducted at Dartbrook Mine (Close to IME facilities) Surface trials at Moranbah North Underground trials Drift to face 24/7 OEM Expertise at site during install 70t Roof Support Carrier Specifications: 33.7t Tare Weight with 70t Carry Capacity 190kW 3126 Cat Engine Hydrostatic Drives 1800 x R33 Tyres with Hutchinson Inserts 15

16 70t Roof Support Carrier Loaded Chain Lifting Mechanism Carrier with Lifting Plate Mechanism 16

17 Carrier Cockpit with Camera Screens SETCO Camera Off-driver side 17

18 Carrier Trial Down Drift Measuring Clearances on Trial Run 18

19 Carrier Turning at Intersection Clearance Between Carrier and Rib 19

20 Installing Roof Supports on Face First Supports on the Face 20

21 Last Roof Support Entering Mine ED40 and 936 Transporting Tail Gate Drive 21

22 70t Dozer Surface Trials Shearer Installed at Tail Gate 22

23 Face Installation Complete Training Committee Meeting 2 nd Tuesday Each Month Contractor Safety & Health Committee Meeting 3 rd Thursday Each Month Daily Muster Brief 0600 & 1800 MNC Crew Toolbox Talks & Pass Meetings Weekly Pit Planning Meeting Thursday 1430 Schedule Update Weekly Longwall Planning Meeting Wednesday 1200 Weekly Safety Team Meeting Monday

24 ACHIEVEMENTS DURING INSTALL PROCESS Anglo American s commitment to Zero Harm was maintained at all times: Zero Lost Time Injuries (LTIs) or High Potential Incidents (HPIs) Expenditure within budget Equipment damage was minimal Progress was good (Delays: Drift closures, BSL Overhaul, Goaf gas) Remained focussed on critical path CONCLUSIONS Selection of a support system is a complex task It requires a detailed assessment of conditions, geotechnical requirements, productivity and financial evaluation Moranbah s 1,750t support system has been a success story from the start to date. 24