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

SITE LOCATION Austar Coal Mine

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

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

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

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

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

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

ZONE 1 – Rib Conditions Austar Coal Mine

ZONE 1 – Rib Conditions Austar Coal Mine

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

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.

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

ZONE 1 – Floor Conditions Austar Coal Mine Skulls and Brattice

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

ZONE 2 – Roof Cavities Austar Coal Mine

ZONE 2 – Roof Cavities Austar Coal Mine

ZONE 2 – Roof Cavities Austar Coal Mine

ZONE 2 –Cavity Recovery Austar Coal Mine

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

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

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

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

ZONE 3 – Cavities Austar Coal Mine

ZONE 3 – Cavities Austar Coal Mine

ZONE 3 – Cavities Austar Coal Mine

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

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.

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

CONCLUSION Safety First and Development will Follow Austar Coal Mine

QUESTIONS? Austar Coal Mine