| Failure of Lift Machinery |
18/11/2003 |
A dangerous occurrence and two major injury accidents occurred during a single incident on the surface of a large miscellaneous mine. Hauliers had delivered a 10.25T alternator to an independently owned and operated power station that was within the mine curtilage. The positioning of the alternator at the rear of the articulated trailer prevented it being unloaded using the crane mounted on the tractor unit of the delivery vehicle. The driver detached the tractor unit, positioned it alongside the trailer and then attempted to reposition the alternator on the trailer bed. The stabilisers had not been fully deployed and the tractor unit overturned. |
| Failure of Plant - Manriding |
15/10/2003 |
A joint broke above the loop section of the drive of a conveyor used for manriding and mineral transport causing the belt to part by 33m. No persons were on the conveyor at the time of the incident. |
| Failure of Plant - Manriding |
03/11/2003 |
In an intake airway a remotely operated manriding and mineral belt broke in the drive due to friction after it tripped and the control room operator attempted to restart the belt six times consecutively over a seven-minute period. The loop of this static belt was full and it tripped out showing belt slip. The control room attendant was aware that belt should not be remotely started after three attempts and the control room logic had not been updated to prevent more than three consecutive attempts to restart contrary to an owner's instruction. No one was on the belt at the time |
| Fall of Ground |
05/11/2003 |
A fall of ground occurred in a rock bolted tailgate 200m outbye of the retreat face. The fall extended across the width of the roadway for a distance covering roof straps at one metre centres. The maximum height of the cavity was estimated at one metre taking into account the bulking of the mudstone and the deformation of the mesh. This area was reinforced by spot bolting during the development phase, to take account of mudstones of varying thickness overlying the seam. The mine will now set additional wooden cribs and consider long strand reinforcement to reduce the likelihood of a recurrence. |
| Fan Stoppage |
08/12/2003 |
During a period when there were no persons underground, the ventilation of a mine was substantially reduced for a period exceeding 30 minutes following the tripping of the dedicated 6.6kV power supply to two underground booster fans on surface transformer. The electrician-in-charge quickly brought standby equipment into use limiting the stoppage period of one booster to only 33 minutes but the monitoring outstation for the second booster failed to come on line and a decision was made that the second booster should not be restarted until men entered the mine on the following morning. The main surface fan continued running throughout and no adverse environmental conditions arose from the stoppage. |
| Fan Stoppage |
20/11/2003 |
The ventilation of a mine was substantially reduced for 41 minutes when the main ventilating fan's 11kV supply tripped on transformer earth leakage protection and there were delays in the electrician operating the powered louvres and starting the standby fan. No adverse environmental conditions were encountered underground during the stoppage. The mine has modified its procedures to ensure that standby equipment is brought into use more quickly. |
| Fan Stoppage |
12/12/2003 |
At the start of the dayshift at a small miscellaneous mine the alarm system indicated that the main fan was not running, it having stopped sometime during the night shift when no one was at the mine. Some fan blades had sheared from the impeller of the axial fan, probably due to bearing failure. A 90KW centrifugal fan was obtained and put into service while the axial fan was sent away for complete overhaul. |
| Fire Underground |
13/10/2003 |
At a large miscellaneous mine, fire broke out underground in the diesel engine compartment of a forklift truck. Hot exhaust fumes from a broken tail pipe impinged on the soundproof foam lining inside the engine covers causing it to ignite. The driver quickly extinguished the small fire using a portable extinguisher, and no person suffered any ill effect. The exhaust pipe failed at a flexible joint as a result of a defective support bracket, which was not identified because routine maintenance was overdue. The usual practice of removing the insulation under engine covers during commissioning, to reduce the fire load, had been overlooked. |
| Fire Underground |
09/11/2003 |
While investigating raised CO levels detected by the mine environmental monitoring system, a command supervisor and a workman found an area of smouldering coal fines beneath a belt conveyor. They damped it down and spread stone dust. The ignition source proved to be a failed bearing in the blind side of a three-piece, suspended trough idler set. There was some indication that it had been mechanically overloaded. No self-rescuers were worn and no person was withdrawn. Alarms had been generated for some hours without proper investigation. The conveyor has since been thoroughly cleaned and reslung to prevent mechanical overload, and control room procedures have been tightened. |
| Fire Underground |
27/11/2003 |
In the main arterial intake roadway at a large coal mine a transfer point attendant saw flames up to 100mm high coming from between the drive gearbox and coupling housing of a large belt conveyor drive. He discharged used a 9kg extinguisher to extinguish the flames. It appears that the traction coupling had migrated towards the gearbox and the gearbox-coupling studs were touching the coupling generating frictional heat. There was no visible damage to the spacer fitted to prevent the studs catching the coupling. |
| Fire Underground |
15/11/2003 |
At the start of the working day at a small coal mine officials noticed that the fire detector in the return drift was in an alarm condition. They traced the source to a burnt out electro-hydraulic loading shovel that had been parked some 10 hours before at the end of the previous working day. They quickly extinguished the remnant fire. The motor cooling fan was heavily contaminated by fine coal soaked in oil emulsion and this appears to have been ignited by frictional heat that had built up by contact with the rotating impeller; any cooling effect being lost when the machine was switched off. The fire eventually spread to the electric cables, hydraulic hoses and three of the shovel's rubber tyres |
| Fire Underground |
16/12/2003 |
In a miscellaneous mine the driver of a drill rig saw a red glow and small flames from a cable supplying the machine's lighting. He discharged a fire extinguisher and put out the flames. The 24V cable had sustained damage, probably by falling stone. The cable has been rerouted and the protection provided for the 24V system augmented by an inline fuse. |
| Locomotives |
01/10/2003 |
A rubber tyred 37kW Bo-Bo locomotive set off pushing a lightly loaded, single flat vehicle up a slight gradient when all four wheels of the locomotive's trailing bogie derailed bringing the train to rest. The power to the 18.7kW motor on the leading bogie had failed due to a fault on the armature contactor, and the increased load on the trailing bogie caused it to tilt, twist and derail. The failure mode indicated the need for design modification of the contactor. |
| Locomotives |
07/10/2003 |
Whilst breasting a single loaded vehicle out of an inbye charging station by a 37kW rubber tyred Bo-Bo battery locomotive, the vehicle and the leading bogie were trailed through a set of clamp lock points. On driving the loco back through the points, the trailing bogie followed the curved track, resulting in the loco reaching its maximum articulation and becoming derailed on all four wheels of the trailing bogie. |
| Locomotives |
27/10/2003 |
While travelling along a main return down a 1:20 gradient, a 15t, 0-4-0, steel-tyred, battery loco hauling a 16.5t unbraked load consisting of five loaded vehicles, ran into a gravel arrester and was brought safely to rest. No one was injured and no serious damage arose. The circumstances have been discussed with drivers to try and improve procedures for safe approach to the arrester. |
| Locomotives |
27/11/2003 |
While slowly passing over facing points in the main line direction at a ' Y' junction turnout on a main locomotive road, a 15t, 0-6-0, steel tyred, single-ended diesel locomotive, hauling 4 covered manriding carriages, derailed and came to rest with all 6 wheels and the first pair of wheels of the leading carriage off the track. The driver was slowing down to let someone off the train when the locomotive derailed at the points. No one was injured and no serious damage was caused. The points had been bolted in the correct position for the mainline direction of travel but had become partly open due to the end of a load binder chain getting fast in the converging gap during a previous materials transport journey. Improvements to load binder chain security and locking of the points have been introduced to reduce the likelihood of a recurrence. |
