Unreported Methane HPI’s Floor Seam Inrushes. Inspector Brown Unannounced Inspection 3rd May 2017
On the 3rd of May 2017 Inspector Brown made an Unannounced Inspection of Grosvenor Mine.
MRE – Grosvenor Coal Mine – 03.05.2017.pdf
Inspector Brown issued the following Directive
1 . Conducting investigations into the floor heave events causing uncontrolled releases of methane contained within MREs dated 3/05/17, 4/05/17. (to be completed by 19/05/17) and:
2. Identify SHMS controls to be developed or reviewed specifically for identifying, managing and controlling the risk of uncontrolled methane releases induced by floor heave. Provide the Inspector with a report of actions taken immediately and proposed actions to address the issue. (to be completed by 26/05/17)
Brown notes he had read the previous 48 hours of Statutory Reports and noted
1/05/17, this incident report identified “Off Scale” alarms on the 4 gas Altair instrument, 1.35%, methane present within the fan ducting
The incident dated 2/05/17 does not identify the level of gas that tripped the auxiliary fan.
There are numerous reports of floor heave through Statutory reports from 3/05/17 and back to 6/03/17 (which was as far back as I checked while on site).
There was a report on the 6/03/17 (report number 12984) of an auxiliary fan trip due to surge of methane.
Another report on 9/04/17 (report number 14091) of an auxiliary fan trip due to surge of methane after floor heave event.
Inspector Brown then observes
My concerns from these events is there is a lack of follow up investigation into the circumstances.
The current phenomenon of floor heave in the gateroads is not fully understood meaning understanding and tracking the mechanism that is initiating the heave and, where is the reservoir of methane that is being released during the floor heave events?
The hazard is not currently identified on the Geological Hazard Plans and is not referenced within the Permit to Mine.
We do not know what Grosvenor Mine Management stated as the SHMS controls to be developed or reviewed as required by the 26th of May 2017
One thing we do know is that methane gas from floor seams continues up until the day of the Methane Ignition on the Longwall Face, or as injured Mineworker Wayne Sellars put it
Q During the life of longwall 104, do you recall instances of methane essentially coming up through the floor of the longwall?
A. Yes.
Q Do you recall whether that was something that happened all the way through from 9 March onwards or did it start to 28 happen towards 6 May?
A It had been there for a while, actually, yes. I can’t recall if it was right at the very start, but, yes, we had methane coming through the floor, bubbling through the floor, for quite some time, yes.
Inspector Brown also noted in the Mine Record Entry a number of issues
The surface Statutory Notice Board in the Muster area was not up to date, there was an MRE absent, the V.O’s monthly report was more than 3 months old and the Safety Bulletins were not the most recent Bulletins issued.
This is neither the first or last time that Mines Inspectors note issues with the Statutory Notice Board not being up to date
Mr Ivers gave an undertaking this would be addressed.
The MG 103 floor heave events were discussed in detail.
I highlighted the incident report dated 1/05/17, this incident report identified “Off Scale” alarms on the 4 gas Altair instrument. The report also identified 1.35% methane present within the fan ducting. The incident report does not contain the level of detail required to fully understand all circumstances and actions taken.
The fact the Altair is recorded as off scale should escalate the investigation process and determine if CMW’s where exposed to danger being, methane greater than 2.5% in general body.
The incident dated 2/05/17 does not identify the level of gas that tripped the auxiliary fan which was stated by UMM Ivers to be 2.01% methane, again more detail and further investigation required.
There are numerous reports of floor heave through Statutory reports from 3/05/17 and back to 6/03/17 (which was as far back as I checked while on site).
Gas leaking from bolt holes on MG 102 install face has been planned to pressure grout on the faceline, noted in the oncoming Nightshift planning notes.
