12th Annual Longwall Conference

Design and Concept of Longwall Top Coal Caving from

Austar Coalmine to North Goonyella Coalmine

Introduction

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Speaker

Steven Chandler

• Initial Longwall Top Coal Caving kit at Austar Coalmine

• Phase 2 Longwall Top Coal Caving kit at Austar Coalmine

• Phase 3 Longwall Top Coal Caving Kit North Goonyella Coalmine

• Phase 4 ( Proposed ) at Austar Coalmine

• Future Developments of LTCC in Australia

Initial LTCC at Austar Coalmine

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Design for the Austar 2 leg shield was developed in China by the Yanzhou

Mining Company ( Part of the Yankuang Group )

Yankuang Group owned the patent for the 2 leg LTCC Shield

Yankuang Group and DBT developed the 2 leg caving shield and manufactured to DBT Standard

Yankuang purchased Austar Coalmine to Introduce LTCC System of mining to the western world

Austar face first full face of 2 leg caving shields in the world

Initial LTCC at Austar Coalmine

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• Greta Seam Coal Measures

– 5.5m – 7m thick

– low strength (5 - 8MPa)

– Immediate 15m of roof laminated (20-60MPa)

• Immediate floor soft mudstone (20MPa)

• Geotechnical Issues

– seam highly cleated and jointed

– inseam shear zones

– High horizontal stresses (40-50MPa)

• Operational Issues

– 1m of coal in the floor on development

– LTCC requires 8.5m to 9.5m wide installation roadway

Initial LTCC at Austar Coalmine

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• LTCC Kit had to be down rated

The Drift is the largest constraint on the capacity of the mine

• The same drift infrastructure is still operating today

• Drift belt capacity 1000t/hr

• Maximum load for drift winder 54 tonnes

• Envelope for drift transport 3250mm x 2400mm

• Caterpillar ( DBT then Bucyrus ) & Yancoal worked closely with the design of the equipment to allow it to be stripped into manageable size units

• Selecting and educating the Longwall crews to extract the above horizon .

Initial LTCC at Austar Coalmine

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MG ROADWAY

SUPPORT

REAR AFC

DISCHARGE

FACE SHIELD

FRONT AFC

CRUSHER

BSL

Initial LTCC at Austar Coalmine

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Initial LTCC at Austar Coalmine

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• EL 2000 Shearer

• 540 kW AFC Motors with KP 45 class CSTs Chain speed 1.1m/s

• 400kW Crusher and BSL motors Chain 1.5m/s

• 2 x leg 1900/3500 mm 971 ton shield

• Canopy Ration of 2.3 :1 Leg angle of 12 degrees and caving angle of 29 degrees

• 6 leg Gate end shield

• AFC centres of 6.9m with bent rear AFC

• Open Bottom Rear AFC pans 1142 mm PF 5 42mm chain

• 1342mm BSL

• 150m face for A1 Panel the 220m A2 Panel

• PMCR electro Hydraulic shield control

• BSL Current control

Phase 2 LTCC at Austar Coalmine

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The opportunity for this was the re-handing of the Kit for Area 2

Improvements implemented

• Move the Rear Tail gate drive from the end of the face to 4 shields into the block

• Rear TG drive on a base plate with tunnels

• Introduce 4 larger capacity 4 leg shields operating 1 web back at the Tail gate end of the face

• Introduce the Cross frame and P drive onto a 1542mm base for the Rear AFC MG Drive but the BSL is only 1342mm, extra room for coal flow past front drive

• Introduce 2 x 4 Leg Buttress shields into the Maingate inbye of the cross frame

• Shorten the Roadway shield and position at highest abutment area of the Main gate roadway

• Straighten the Rear AFC and decrease the AFC centres to 6.150m

• Lower the TG drive and apply 3.5 degree attack angle to the bed plate

• Flatten out the Rack bar at the MG so the shearer does not lift

• Introduce Big Foot ( a hydraulic stab jack) to Lift the Goaf side of the Front MG drive

Phase 2 LTCC at Austar Coalmine

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Phase 2 LTCC at Austar Coalmine

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Phase 2 LTCC at Austar Coalmine

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Phase 2 LTCC at Austar Coalmine

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Phase 3 of the LTCC North Goonyella Coalmine

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• The Yancoal / Peabody LTCC project provided to opportunity to develop and

implement phase 3 of the LTCC equipment .

• A detailed review of the Austar kit identified many areas of improvement, with

these implemented into the design with Caterpillar for the North Goonyella

equipment to improve reliability, efficiency and maintainability.

• 1000mm web was selected due to following reasons

1. Lower extraction height improved roof strength ( thicker beam, Austar Mine )

2. Increased support density of the new shield

3. Shield Lower . Advance . Set. operating one shield behind leading drum

4. Variable cutting cycle designed to assist with face conditions and production

Phase 3 of the LTCC North Goonyella Coalmine

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New equipment design to improve the efficiency of the LTCC performance.

• In-line rear AFC drive unit ( AFC centers 7.150m with both AFC parallel )

• 3 leg special gate end shields with increased advance force on the DA ram

design ( to improve support density at gatends )

• Cross – frame rear M/G drive arrangement

• Side shift cylinder from rear of No 3 shield to base plate of rear AFC cross frame

• Mono rail mounted pump station

• Double ended Pump motors with pumps mounted on both ends

• Fully automated cutting and caving cycle with automated Dust control

• Closed bottom rear AFC with Coal saver attached to improve recovery of Top

coal

Phase 3 of the LTCC North Goonyella Coalmine

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Due to the difficult Middle Goonyella seam the Run of face shield design was

improved to provide a higher support density

These are

• Shield centres 2050mm

• Increased Cylinder leg size to 450mm

• Improved shield hydraulic circuitry to reduce return pressure

• Leg angle increased slightly

• Caving Canopy angle increased slightly

• Canopy ratio 2.29 :1

• Caving door position constant thru height range

Phase 3 of the LTCC North Goonyella Coalmine

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North Goonyella Mine

Run of face shield Austar Mine

Run of Face Shield

Phase 3 of the LTCC North Goonyella Coalmine

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Phase 3 of the LTCC North Goonyella Coalmine

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Phase 3 of the LTCC North Goonyella Coalmine

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Phase 3 of the LTCC North Goonyella Coalmine

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• Tons per metre /Shear = 2512 tons

• Sheared Coal = 1542 Tons Caved Coal = 970 Tons

• 305m face , 3000t/hrs system

• 1200Kw drives on the AFC with 600Kw drives on Crusher and BSL

Phase 4 ( proposed) LTCC at Austar Coalmine

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• Replacement of the 6 leg shield with the 4 leg shield

Phase 4 ( proposed) LTCC at Austar Coalmine

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Future Development of LTCC Equipment

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• Reduce the Length of the Rear Tail gate Drive unit

• Design Walking Tailgate roadway shields

• Onboard shearer dust scrubber

• Determine the most efficient cut to cave ratio

• Determine the most efficient face length

• Mobile fleet that can efficiently relocate the size of the current LTCC kit

• Reduce the amount of coal left in the Goaf

• Improve Maintenance Strategies to achieve higher engineering availabilities

• Therefore higher % utilization and higher productivity at lower cost .

Conclusion

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• Australian coal companies need to embrace this concept

• Maximize Resource Recovery

• New Technology concepts developed from the Operators

• The Operators work closely with the Designers from Caterpillar to improve the

design of the equipment

• Keep the Process Simple

• Maintain High Operational and Engineering Standards

• Automation