1. AUSTAR COAL MINE A2 MAINGATE ROADWAY DEVELOPMENT Experiences and Lessons Learned Presenter Glenn Sobey Development Mining Engineer Austar Coal Mine

2. SITE LOCATION Austar Coal Mine

3. AUSTAR IN BRIEF Owned and operated by Yancoal Australia. Better know for the introduction of the LTCC Longwall Face Mines the Greta Coal Seam. Development to date utilising 2x ABM20 and 1x ABM25 Continuous Miners. Austar Coal Mine

4. MINE OVERVIEW Austar Coal Mine CURRENT WORKINGS PROPOSED WORKINGS OLD ABANDONED WORKINGS A2 Maingate

5. A2 MAINGATE Total Block Length 1179m Design Pillar Dimensions of 100m x 35m Profile – 5m wide x 3.2m high Mining Horizon – 1.5 > 2m Coal Tops 2x ABM20 – Twin and Super Unit Austar Coal Mine

6. MINING CONDITIONS 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) Austar Coal Mine

7. A2 MAINGATE Zone 1 – 2>6c/t – Soft Ribs and Soft Floor Austar Coal Mine Zone 1Zone 2Zone 3 Zone 2 – 5>9c/t – High Pressure Stress Zone Zone 3 – 10>14c/t – Continuous Cavity Zone

8. ZONE 1 Zone 1 –Characterised by Soft Ribs and Soft Floor –Rib conditions Structure driven –Floor conditions Water driven Austar Coal Mine

9. ZONE 1 – Rib Conditions Austar Coal Mine

10. ZONE 1 – Rib Conditions Austar Coal Mine

11. AUGER STEELS Austar Coal Mine The Auger Steel cleared the cuttings far more effectively then the standard Scroll Steel in sugary coal.

12. ZONE 1 – Floor Conditions Austar Coal Mine Water from the flooded workings immediately Up Dip of the A2 Maingate caused the soft mudstone floor to break up during wheeling.

13. FLANKING HOLES Drilled in advance of the Development Roadways to control the water seepage into the roadways. Repeat of the practise adopted for the A1 Maingate. Peak water make from some of the holes + 5 l/s. Austar Coal Mine A1 Flanking Holes A2 Flanking Holes

14. ZONE 1 – Floor Conditions Austar Coal Mine Skulls and Brattice

15. ZONE 2 Zone 2 –High Pressure Stress Zone –Cavities forming in front of the Miner –Face busting out 2m ahead of the cutter head and 2m above the Top of Coal Austar Coal Mine

16. ZONE 2 – Roof Cavities Austar Coal Mine

17. ZONE 2 – Roof Cavities Austar Coal Mine

18. ZONE 2 – Roof Cavities Austar Coal Mine

19. ZONE 2 –Cavity Recovery Austar Coal Mine

20. MESHXPRESS PLATES Austar Coal Mine MESHXpress Plates used to pin the mesh to the spot bolts

21. Wyberex Bolts Austar Coal Mine Wyberex Bolts installed and PUR’d to form an artificial beam in the roof above the Dosco marker band. Bolts in the Rib angled out to reinforce the Rib inbye the face. 300mm x 300mm Pattern Dosco Band 4m Wyberex Bolt 2m Wyberex Bolt

22. Cavity Recovery Permit Permit System introduced due to the high risk nature of recovering the Cavities. Permit includes: –A minimum number skilled competent and experienced operators –The correct materials for the task Austar Coal Mine

23. ZONE 3 Zone 3 –Continuous Cavity forming between the face and the last line of support. Austar Coal Mine

24. ZONE 3 – Cavities Austar Coal Mine

25. ZONE 3 – Cavities Austar Coal Mine

26. ZONE 3 – Cavities Austar Coal Mine

27. Cavity Support Austar Coal Mine CROWN SUPPORT EDGE SUPPORT CROWN SUPPORT EDGE SUPPORT MESH

28. PRODUCTIVITY Austar Coal Mine Zone 1 Zone 2 Zone 3 Development in Zone 1 and 2 off-set by Twin Miner. Modify Sequence to cope with Conditions. Zone 3 Driven as Super Unit.

29. SAFETY Nil Lost Time Injuries Nil Disabling Injuries Key Factors Training Attention to Detail Close Supervision, Systems There were 2 First Aid Injuries due to roof material Austar Coal Mine

30. CONCLUSION Safety First and Development will Follow Austar Coal Mine

31. QUESTIONS? Austar Coal Mine