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Falls Of Ground Incidents - Reporting Year 1998/1999

Contents

Introduction

1. This report summarises the fall of ground dangerous occurrences and both fatal and major injury accidents reported at mines during the 1998/99 reporting year.

2. All statistics are provisional.

Dangerous occurrences

3. Any fall of ground not being part of the normal operations at a mine, which results from a failure of an underground support system and prevents persons from travelling through the area affected by the fall or which otherwise exposes them to danger, was introduced as a dangerous occurrence at Part II/40 in RIDDOR 1995, with effect from April 1996. This is the third full year that such incidents have been reported to HMInspectorate of Mines.

4. Seven falls of ground were reported at mines during the year, six at coal mines and one at a miscellaneous mine.

5. Three of the falls occurred in places that had been recently driven, one occurred in a place that had been excavated between six to twelve months previously and three in places that had been excavated for more than five years.

6. In coal mines all the incidents occurred in places that were supported by free standing passive supports such as arches, props and bars etc. One fall occurred at a miscellaneous mine. Four of the falls occurred in roadways, three in bord and pillar roads and one at a major junction

7. At the miscellaneous mine the fall occurred in a roadway which used yielding pillars as the main support with rockbolts used to prevent localised spalling.

Fall of Ground Dangerous Occurrences

Type of Support
Free-standing support 6
Rockbolted -
Miscellaneous 1
Total 7
Warning of Collapse
None 5
Less than 24 hours 1
Over 24 hours 1
Total 7
Age of Excavation
Recently driven 3
6 - 12 months 1
Over 5 years 3
Total 7
Type of Excavation
Junction -girders 1
Junction -rockbolts -
Junction -natural support 1
Roadway - props and bars 3
Roadway - arches 2
Roadway - rockbolts -
Faceline -
Total 7

Accidents

8. There were three fatal accidents and twenty major injuries reported at coal mines compared with one fatal and twenty two major injuries in the previous year.

9. There were three major injuries reported in miscellaneous mines compared with one the previous year.

10. At coal mines twelve of the accidents occurred in places supported by free standing supports, nine where powered supports were used and two in places supported by rockbolts.

11. A double fatality occurred at a small mine when a command supervisor and workman were trapped by a substantial fall of roof at the roadhead area of a 1.65m high coal heading. At the time they were re-setting timber middle sets, under steel straps, which had kicked out at the feet due to weighting of weathered strata in the roadway which was only 38m below the surface.

The third fatality occurred in a 12m wide × 1.7m high retreating stall heading, supported by wooden props and bars, when a 2.7m × 2.0m × 0.1m piece of fossilised mudstone fell out of the roof trapping the workman briefly adjacent to fired coal at the ribside of the stall. Although suffering fractures to his right leg and pelvis he died several weeks later in hospital.

1997/1998 1998/1999
All - mines fall of ground accidents Fatal Major injury Fatal Major injury
Coal mines - free standing supports - 13 3 9
Coal mines- powered supports - 5 - 9
Coal mines- rockbolts 1 4 - 2
Miscellaneous mines - 1 - 3
Total 1 23 3 23
1997/1998 1998/1999
Coal Mines - place of accident Fatal Major injury Fatal Major injury
Longwall face - 7 - 11
Headings - 13 3 6
Elsewhere 1 2 - 3
Total 1 22 3 20

Conclusions

The number of falls of ground dangerous occurrences have reduced to seven this year compared with twelve last year and it is of note to record that those in coal mines occurred in roadways supported by passive supports with no falls recorded in rockbolted roadways.

It is disappointing however, to record that there has been little change in the number of accidents due to falls of ground with three fatalities recorded this year against only one last year. Although there has been a significant decrease in accidents in headings there has been a noted increase in accidents on longwall faces mainly where remedial support work has been carried out to deal with cavities and poor roof conditions in advance of the powered supports.

H C Evans
HM Principal Inspector of Mines
13 May 1999

2012-11-27