North Goonyella Fire MRE 8th September 2018

MRE – North Goonyella – 08.09.2018.pdf

 

Today, 8 August 2018 1, Inspector Les Marlborough, attended a meeting at North Goonyella Mine to discuss the status of the high CO in 9N TG. I was met by UMM Mr Marek Romanski and SSE Mr John Anger.

Meeting

Attending the meeting was;

Mr John Anger, SSE;

Mr Marek Romanski, Underground Mine Manager;

Mr Robin Hall, Continuous Improvement Manager;

Mr Charles Lilly, Peabody Senior Director of Engineering;

Mr Ash Sauer, EEM;

Mr Peter Baker, Peabody Underground Operations Manager;

Mr Lee Earnshaw, Development Coordinator; Mr Andy Thompson, Shift Supervisor; Mr Jamie Haantz, UG Development.

Meeting

Last 24 Hours;-

Inspected the whole of the Mine. Points to note were; Water almost to the roof in MG10 North 17-19 CT B Hdg; LW 9 North take off face standing well. No issues; Set up weekend ventilation in development headings in 10 South. No gas issues in these headings;  No issues of concern for the rest of the Mine other than water build up in some areas.

Other activities;-

• ERL Controllers manned ERL interfaces while power was being restored;
• Power restored to whole of Mine up to 16 CT MG 10 N01th. Non critical equipment was isolated and racked out;

Real time gas monitoring restored;

• Tube 29 repositioned to be representative of GB in LW9N TG Chute Road. This was completed at 17:50 PM 7 Sep;
• Coupled large Floxal unit onto Hole 1991, commissioned and running at 01 :30 AM 8-Sep. Unit delivering 300 1/s at 2-3% Oxygen. Although this unit is rated for 900 Vs, at the higher rate the Oxygen would be 5%. This was considered by the Management team and the decision made to run at the lower rate to minimise Oxygen content. Total flow of Floxal into this hole is now 499 1/s;

There is a small leak at the collar of hole 1991 that will require the Floxal shut down to rectify, Will be done on Day Shift;

Borehole into LW9 North Goaf drilled to 230 m;

• Second Floxal connected to Hole 2470 giving total flow of 446 1/s into that hole; Continued monitoring gases.

Current Status;-

Gas readings for the previous 24 hours were provided. The readings were in line with what was expected;-

• Methane and CO now reporting to the TG Chute Road (Approx 270 ppm CO and methane greater than 2.5%, still varying with barometer) — this is due to the inert gas being injected into the goaf flushing the CO and methane out of the goaf from the TG Chute Road to the TG end. There were no indicators of Spon Com causing concern, such as Hydrogen or

Ethylene. Graham’s Ratio is unreliable due to the Nitrogen being injected into the goaf; o Tube 24 at the TG end of the face was showing Oxygen below 5%, CO down to 131 ppm at 06:20, Hydrogen 9.9 ppm and Ethylene at 0.71 ppm at 06:20;

• Tube 28, the Longwall return was showing readings as would be expected considering the gases coming out of the TG Chute Road.

The Floxal units at hole 1991 had been turned off at approximately 07:00 to complete the repairs to the collar of the hole. The CO at the TG end, very quickly rose from 131 ppm to 265 ppm and was still rising. Methane also dropped by 3.5% and oxygen jumped from 3 to 5%. This seems to demonstrate the impact on the gas at the TG end due to the pressure drop on the goaf when the Floxal stops rather than the loss of flow. This pressure drop allows the goaf gas buoyancy to push the goaf gases back towards the TG. The affects, though not as dramatic, were also observed in the TG chute road.

It was explained that the Mine is running under TARP 7 (sealed Goaf TARP). This was an outcome of the Risk Assessment conducted for the re-entry as being the TARP nearest to the current situation. It was decided to utilise this TARP rather than develop a new TARP. There are parts of the TARP that are not relevant as the goof is not sealed but the TARP allows for essential work to be conducted underground when in code Red with the Mine Manager’ s permission. The Mine had decided that whenever the gas reached the code red trigger all non-essential work and the associated persons would be brought to the surface. I advised the Mine that they should consider establishing a list of what was considered to be essential work to avoid confusion. I also recommended that essential work should be that needed for the safety of the Mine and should include establishing pumping.

2

Plan for the next 24 Hours;-

• Continue monitoring and maintaining inspections to keep the Mine open and safe;
• Continue work to establish the pumping system which would include turning on the pumps and re-energising the compressed air lines;

Other work as detailed in the Mine re-entry plan;

• Continue Floxal injection;

Establish a second inertisation line to the 9N TG seal to introduce more inert gas to the TG end of the face;

The Mine is to investigate whether a second tube bundle line can be run into the TG Chute road and connected to the sample line running to the goaf edge, This is to monitor the air coming through the face past the e-frame to ensure there are no issues with this area of the goaf;

Complete repairs to Hole 1991 collar and re-establish the Floxal injection at this hole.

At approximately 10:30 the Drilling Supervisor reported that they had lost circulation at a depth of 232 metres. This would be due, probably, to subsidence cracks from the goaf. There was discussion as to whether this would be an appropriate time to start injecting Floxal at this point. It was, however, agreed that the best way forward was to put a thick grout into the hole. This would seal the leakage paths and when set, drilling could recommence. This may have to be done several times to allow the hole to be drilled to a depth as close as possible to the seam (coal seam at depth of 400m),

I was advised that the workforce have been advised that, during the re-entry process the underground work would be conducted by volunteers only.

Copies of the current gas data spreadsheets, the Incident Action Plan and a plan showing the Injection points being used and the quantities of inert gas being Injected were provided.

I thanked the people for their time and explained that Inspector Brown would return to the Mine at 9:00 AM on Sunday 9 September to review progress and to discuss plans going forward.

Les Marlborough

Inspector of Mines