| Dangerous
Occurrence Type |
Location
Name |
DO
Date |
Dangerous
Occurrence Precis |
| Failure
of Plant - Manriding |
Kellingley |
23/04/02 | A
manriding belt conveyor in a maingate roadway failed at a mechanical
joint which had worn causing one half of the fastening to open and
release the coupling pin holding the joint together. No persons were
riding at the time. The use of belt joints where the time in use is not
known is to be prohibited. Maintenance instructions are to be reviewed
regarding acceptable wear tolerances. |
| Fan
Stoppage |
Birkshead |
25/04/02 | At
a miscellaneous mine power to the main fan was removed when a 3300 volt
circuit breaker was closed onto a short circuit which had occurred at a
3300 volt bitumen filled coupler. The problem in correctly identifying
the fault had been exacerbated by the fact that an 'oversensitive' 11kV
circuit breaker, remote from the mine, belonging to the supply authority
had also incorrectly tripped at the time of the fault. The electrician
considered that the loss of power to the mine may have contributed to an
'apparent' overload trip of the 3300 volt circuit breaker for the fan.
Among matters being considered by the Manager is that he should require
the use of resin filling instead of bitumen filling for overhauled
equipment supplied to the mine. Also there is a need for more careful,
fuller assessment of potential faults, prior to restoration of power to
what may be a defective circuit. |
| Fire
Underground |
Barrow |
09/04/02 | During
routine load-haul dump operations in a Gypsum Mine, the driver of a Long
Airdox Una-Hauler saw flames rising from around the transmission tunnel
of the vehicle. He activated the onboard piped fire suppression system
which quickly extinguished the flames. No persons were injured and
no-one suffered any ill-effects or wore self rescuers. The bracket
supporting the parking brake calliper had come adrift due to failure of
five securing studs causing a brake hose fitting to fail and spray brake
system mineral oil in the vicinity of the brake. Brakes on two similar
machines are being checked and the brake design is being reviewed in
consultation with the manufacturer. |
| Fan
Stoppage |
Aberpergwm |
09/05/02 | At
the end of a normal production shift, a small drift mine experienced a
total power cut and the local power distribution company advised that
there was a major HV outage affecting a wide area. The 2 × 51kW main
surface fan and four underground auxiliary fans stopped and there was a
substantial reduction in ventilation to the mine lasting for a period of
2 hrs 35 mins. All persons were safely withdrawn to the surface and mine
ventilation was re-established without incident when the power supply
was restored. A standby diesel alternator is to be installed at the mine
to minimise disruptions of incoming supply. |
| Ignition
of Gas Underground |
Maltby |
16/05/02 | At
a large coal mine an ignition of gas occurred at the face of a 4.5m wide ×
2.9m high heading cut by a Joy 12CM18 fitted with onboard bolting
machines. Normally this would be a single pass machine of 4.1m width but
because of rib movement a second pass of approx 0.3m was being
extracted. Overlying sandstone had entered into the extracted section
and the extra width was being mined when the driver saw a glow. Water
from a wander hose was applied and the flame extinguished. No Person was
injured, no deficiency in the ITP protection system nor ventilation
system was detected with GB levels <0.4% CH4. To assist in preventing
a recurrence additional water cannons would be fitted and directed to
the cutting bollards, their effect to be monitored, and the CH4 detector
to be re-sited at roof level adjacent to the last strap set.
Investigation is continuing. |
| Fan
Stoppage |
Thoresby |
29/04/02 | Following
a period of fluctuating and severe barometric pressure changes resulting
in increased methane gas levels discharging from old mine workings, a
booster fan was stopped for a period in excess of 30 minutes. The
ventilation quantity was significantly reduced and workers were
withdrawn. Following a period of barometric stability, the fan was
restarted after a period of 7 hours. The affected district had recently
been reopened having been once part of an abandoned mine. A detailed
inspection of old districts including review of the mine stopping
register was carried out with the manager, group ventilation engineer
and UDM mining engineer. Remedial measures discussed included
construction of new stoppings and balancing of existing ventilation
stoppings. Spontaneous combustion risks were also highlighted. |
| Locomotives |
Gascoigne
Wood |
29/04/02 | While
travelling outbye at relatively slow speed in a long conveyor road on a
slightly rising straight track, a Clayton 50hp rubber tyred bogie
locomotive without any trailing load suddenly juddered and came to rest
with the leading wheels of the rear bogie derailed. Neither the driver
or electrician who was in the rear cab, were injured. Investigation
revealed that drive had been lost to the front bogie due to a mechanical
transmission fault. Heavily worn electric motor brushes were also found
and intermittent motor drive may have contributed. The loss of
mechanical drive is still being investigated. In the meantime
improvements to standards of electrical motor maintenance and testing to
prove drive to the wheels are being pursued. |
| Locomotives |
Riccall |
15/05/02 | While
hauling an empty GMT bogie vehicle into a passbye in a main locomotive
road, at slow speed, the front two wheels of the trailing bogie of a
Clayton 50hp rubber tyred Bo-Bo locomotive derailed bringing the loco to
rest. Nobody was injured and no damage was caused. Investigation
revealed that the safety chain between the loco and vehicle had become
tight on the outside of the outbye half of the curve causing the
derailment. The safety chain was a suitable length but appears to have
been twisted causing it to become too tight for the curve. The
circumstances of the incident are being publicised, instructions
relating to fitting safety chains are being issued and safety chains are
to be painted to make twist detection easier. |
| Locomotives |
Maltby |
31/05/02 | Underground
in the pit bottom circuit of a large coalmine, a 50hp battery powered
BoBo loco travelling without load and at slow speed was brought to rest
by derailment when the wheels on the rear bogie split a set of facing
points. No one was injured and no damage resulted. The lockable turnout
and operating mechanism were found to be obstructed by debris and
grossly maladjusted. Numerous turnouts in the aging pit bottom rail
circuit are high maintenance, and significant attention is required to
restore reliable standards. A technical audit will be carried out to
prioritise a programme of work agreeable to HMI. In the interim,
additional resources will be deployed to points maintenance. |
| Fail
Lift Machinery |
Welbeck |
22/05/02 | Underground
in the battery charging station of a large coal mine, a 6T Becorit
pneumatic lifting beam failed and the 1.4T battery load fell to the
ground. No persons were injured. The cause of failure was found to be a
sheared key on a drive shaft in the lift/lower gearbox on the lifting
beam, possibly caused by repetitive shock loading resulting from a
broken tooth on the reduction pinion on that drive shaft. The lifting
beam and gearbox were installed in 1995. Periodic maintenance since
installation did not appear to include any strip down internal
examination of critical load bearing parts of the gearbox, which
incorporates a load brake unit, although the OEM annual maintenance
requirement is to examine the gearbox internally. Insurance inspections
were up to date and identified no contributory defect. The nature and
frequency of periodic maintenance will be reviewed, as will the role of
insurance inspections. Indications were that there are numerous similar
units currently in use. |
| Fail
Lift Machinery |
Riccall |
18/06/02 | Underground
in a development road at a large coal mine, contractors used a 6T
monorail mounted tug and lifting beam to salvage a 2.5T belt return
section and 3T of trailing cable coiled on top of it, which were located
under an adjacent belt conveyor. Whilst they were applying angle lifts
to progressively 'walk' the return section from under the belt to a
position under the monorail where it could be loaded onto a rail
vehicle, one of the two 3T hooks fractured. No one was injured. The task
was unplanned and a risk assessment was not carried out, either by the
contractor's supervisor or the inspector. Initial indications from
computer records were that the contractors were not trained in safe
lifting. A review of risk assessments for unplanned work, and a review
of contractors training for lifting, will be carried out. Other matters
raised included, means of safe isolation of pneumatic equipment. |
| Locomotives |
Gascoigne
Wood |
24/06/02 | Underground
in a large coal mine, the rear bogie of a 50hp rubber tyred battery BoBo
loco travelling slowly and without load derailed on the curve section of
a trailing turnout. The driver blamed power surging, but no contributory
defect could be found. There was a slight adverse camber on the track at
the incident site, but otherwise it was to an acceptable standard. The
track will be cross levelled as a precaution, and additional tests of
the loco electrical control system will be arranged with the OEM
present. Investigation inconclusive. |
