The Positive Pressure Chamber Austar Coal Mine & Joncris Sentinel Services

1. The Positive Pressure ChamberAustar Coal Mine & Joncris Sentinel Services Austar Coal Mine Proactive:- Spontaneous & Combustible Gas Management- Seal Design

2. What are we up against?

3. Our Challenge • Understand and Manage Spontaneous Combustion and Flammable Atmospheres in Active and Sealed Goaves • Utilise Proactive rather than Reactive Risk Management • Eliminate the Hazard rather than accept the inevitable and use Reactive Management to reduce, control or contain the potential Catastrophic Consequences

4. The Oxidation Process Temperature vs Time

5. Serious Incident

6. Serious Incident Tube Bundle Monitor CO Readings

7. Serious Incident CO Readings – Air Free Basis Analysis

8. Serious Incident – CO Make

9. Serious Incident – Ratios

10. Serious Incident – Gas

11. Inertisation Attempt - GAG The GAG Jet Engine Inertisation

12. Sealing the Mine

13. Re-Entry Controls Gas Monitoring

14. 18% 02 0.3% CO2 0 ppm CO 18% 02 0.3% CO2 0 ppm CO Typical Gas analysis during re-entry : Tube bundle and borehole readings Typical Gas analysis during re-entry : Tube bundle and borehole readings 12% 02 4% CO2 7000 ppm CO 0.5% CH4 6% 02 4% CO2 0 ppm CO 3.5% CH4 6% 02 5% CO2 0 ppm CO 2% CH4 3% 02 6% CO2 1000 ppm CO 4% CH4 3% 02 5% CO2 0 ppm CO 7% CH4 Re-Entry Experience Gas Levels

15. CM Buried in SL5MG Conveyor Road flooded at 6c/t MG Travel road: cables,poly pipe, O2 Rescuers melted Secondary Fire and Roof Fall Found Poly Pipe melted Coked roof coal Charred Conveyor Belt Limit of Exploration Fall of Ground in 6c/t Major Damage Found Re-Entry Experience The Physical Toll

16. Austar Coal Mine

17. Austar Coal Mine Complex

18. Top Coal Caving

19. 25m3/s 140m3/s 70m3/s 80m3/s 70m3/s 35m3/s 35m3/s Ventilation Network

20. FACT: • All underground mine seals leak & breathe • Sealed and Active Goaves = High Risk Problem – Leaking Seals Combustion & Flammable Mixtures in Goaf Areas

21. Effects of Leaking Seals

22. Effects of Leaking Seals

23. Conventional Thinking • Airflow past Seals is governed by the well known relationship: P=RQn • Q = Quantity (measured in m3/s varies from Q2 to Q depending on the nature of the flow - laminar or turbulent) • R = Resistance (measured in Gauls varies from 50,000 to 200 depending on Seal Integrity and more importantly the integrity of the roof, floor and sides - rarely do we see this in the higher quartile) • P = Pressure (measured in Pascals varies depending on Mine Ventilation Pressure; Diurnal and Synoptic Barometric Pressure variations with the latter having the largest impact) • Seals erected pumped or sprayed during Diurnal Barometric Lows will not be as effective as those erected during Higher barometric pressure (try patching a leaking bicycle tyre with bubble gum) • We as an industry continue with the old outdated Strategy and spend Megabucks trying to increase Resistance • This is re-active risk management and doomed to failure

24. Solution to Leaking Seals - Positive Pressure Chamber Concept NORMAL: • Oxygen flow through seal • Potential for spontaneous combustion or explosive mix of gases BALANCE CHAMBER: • Oxygen flow through chamber • Potential for spontaneous combustion or explosive mix of gases POSITIVE PRESSURE CHAMBER: • Nitrogen injected into the chamber • Positive pressure maintained within the chamber • IMPOSSIBLE FOR OXYGEN TO FLOW THROUGH CHAMBER

25. Positive Pressure Effects • Dramatic reduction in combustible (explosive) gases. • Inert and safe goaf (unable to promote spontaneous combustion). • NIL oxygen ingress through the chamber.

26. Positive Pressure Chamber 70m3/hr Nitrogen Inertisation Unit Nitrogen Injection Location 20PSI Structural Seal 5PSI Flexible Seal

27. Nitrogen Injection Sites Positive Pressure System 1936m3/hr Nitrogen Plant. Sufficient to maintain positive pressure across 24 different Positive Pressure Chambers.

28. Sealing Effectiveness – TG End

29. Sealing Effectiveness – MG End

30. World First Innovation • Eliminated one of the biggest risks to the mine • Simple and safe • Reliable & low maintenance (>99% availability) • Proven: • First trial September 2005 (70m3/hr) • System has been running since September 2006 (1936m3/hr) • Positive Pressure Chamber System Costs (large 1936m3/hr Unit): • Infrastructure = $250,000 (including reticulation). • Leasing and running = $0.07 per m3 of Nitrogen. • Annual costs ~$1.2 million (continuous use at full capacity) $ • Set the benchmark for managing risk of combustion / explosive atmospheres in underground coal mining & Panel Sealing. • Australia and world wide application and interest Implementation

31. SEAL LEAKAGE • Build a seal • Seal leaks or breathes resulting in oxygen ingress through or around the seal • Monitor for changes in the potential explosive atmosphere or for signs of spontaneous combustion • React to explosive atmosphere or heating – IF POSSIBLE!! Risk Management Current Mining Practice - Reactive SPONTANEOUS COMBUSTION OR EXPLOSION

32. CHAMBER • Inject Nitrogen into chamber (+’ve pressure) • Encourage nitrogen ingress into the goaf 1. Eliminates risk of spontaneous combustion (heat) SPONTANEOUS COMBUSTION OR EXPLOSION 2. Eliminates risk of explosive atmosphere Risk Management The Pressure Balance Chamber System - Proactive • Build a chamber • Eliminate Oxygen ingress into the goaf • Inert goaf which:

33. The Positive Pressure Chamber has effectively ELIMINATED one of these seven MAJOR HAZARDS. And put a few holes in another one. Significance COAL DUST TRANSPORT SPONTANEOUS COMBUSTION INRUSH STRATA OUTBURST FIRE & EXPLOSION • There are seven (7) prescribed MAJOR HAZARDS for an underground coal mine.

34. History does not need to repeat itself. In Summary The Positive Pressure Chamber