North Goonyella Mine Record Entry 3rd September 2018. Les Marlborough Inspector of Mines
LM MRE – North Goonyella – 03.09.2018.pdf
Today, 3 August 2018 1 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.
Meeting
Attending the meeting was;-
Mr Marek Romanski, Underground Mine Manager; Mr Dennis Black, Ventilation Officer;
Mr Nev Impson, Compliance Manager.
Mr Romanski gave me an update of progress during the night. The planned ventilation change, closing down 1 surface fan, had occurred at 6:00 PM on 2 September. This was modelled at reducing the face quantity to 20 m Is with only 2 m Is reporting to the TG hatch. Mr Romanski explained that these quantities could not be confirmed as people were not allowed underground.
As expected, the initial trend was favourable on tube 24 (the tube sampling the LW 9N TG Goaf edge), with the CO levels dropping over a 2-4 hour period. The CO went down to 148 ppm at 7:55. Then the CO rose up to peak at 767 ppm at 02:00 AM. Successive bag samples during the night showed the CO level dropping to 558 ppm at 08:00. The bag samples also showed Ethylene increasing to 3.7 ppm at 02:00 and dropping to 2.5 ppm at 08:00. Mr Black stated that the Graham’s Ratio was around 1 and was falling. It was seen that the CO make at the TG Regulator had dropped from 154 1/min before the ventilation change to 106 1/min at 08:00 AM.
Mr Romanski explained that the Mine had started putting Methane into the goaf at a goaf drainage hole 2470 situated 89 m from the face opposite the TG chute road. 300 1/s of methane was being injected. The Methane level at tube 24 at 08:00 AM was 10.52%. The Oxygen level at 08:00 was 10.52%. The Oxygen had consistently been falling from 17, 7% at
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8:00 PM. He also stated that a larger Floxal unit was due to arrive on site at 12:00 noon. The Floxal units were capable of producing 250 IIS.
The Mine’s plans for the next 24 hours was to run another pipe on the surface to connect to another gas riser to increase the Methane injection to approximately 1 ,000 1/s.
Mr Romanski stated that Underground power had been shut off as per Inspector Marlborough’s recommendation.
The Mine’s plans for the next 24 hours were;-
- Set up the large Floxal unit onto a gas riser (hole 1991) located 134 behind the TG end of the face.
- Run a second 6″ pipe to connect to a second gas riser on the South Side to increase the Methane being put into the goaf at hole 2470 to approximately 1 ,000 Ifs.
I recommended that the Mine establish the following;-
A mine plan showing current ventilation set up with quantities, monitoring points, inertisation points and points where Methane was being injected into the goaf;
2 Establish a detailed timeline of events. This to commence when the Longwall was approximately 50 m from its finish point. The timeline to detail the following as a minimum; Milestone events such as roof falls, ventilation changes, bolting runs etc; Gas readings, CO Make etc at key points before and after milestone events;
Air quantities (could be taken from ERZ Controllers’ stat reports);
- Changes in monitoring locations;
- Any other details to assist in the determination of what had caused the heating in the goaf.
I thanked the people for their time and explained that I would return to the Mine at 08:00 AM on Tuesday 4 September to review progress and to discuss plans going forward.
Les Marlborough
Inspector of Mines
