|
I'm indebted to Joe Stocks for sending me the Report
by
J.W. Calder, C.B., O.B.E., B.Sc., C.Eng., F.I.Min.E.Chief Inspector of Mines and Quarries.
On the causes and circumstances attending, the inrush which occurred at Lofthouse Colliery on the 21st. March 1973.
It is the only source of information used on this web page.
Inrush at Lofthouse Colliery.
21st. March 1973.
The disaster was caused by an inrush of water from old workings.
Seven men lost their lives.
Frederick William Armitage, aged 41, occupation Face Worker.
Colin Barnaby, aged 36, occupation Face Worker.
Frank Billingham, aged, 48, occupation Face Worker.
Sydney Brown, aged 36, occupation Face Worker.
Charles Cotton, aged 49, occupation Face Worker.
Edward Finnegan, aged 40, occupation Deputy.
Alan Haigh, aged 30, occupation Face Worker.
Public Inquiry.
Held on 30th. May 1973, at the No.1 Crown Court, Wakefield.
Inquiry lasted eight days.
61 persons gave evidence.
Interested Parties were represented: -
The Department of Trade and Industry.
Mr. R.T. Purvis, H.M. Divisional Inspector of Mines and Quarries.
Mr. J. Carver, H.M. Deputy Chief Inspector of Mines and Quarries.
Mr. A. Harley, H.M. Senior District Inspector of Mines and Quarries.
Mr. S. Luxmore, H.M. Principal Electrical Inspector of Mines and Quarries.
The National Coal Board.
Dr. H.L. Willett, Deputy Director General (Mining).
Mr. T. Wright, Area Director, North Yorkshire Area.
Mr. W. Forrest, Chief Mining Engineer, North Yorkshire Area.
Mr. T. Mapplebeck, Production Manager, (Manager of the Colliery at the time of the Accident).
The National Union of Mineworkers.
Mr. A. Scargill, Acting General Secretary, Yorkshire Area.
Mr. J.T. Leigh, Vice President, Yorkshire Area.
Mr. T. McGee, Mining Engineer, Yorkshire Area.
Mr. R. Horbury, Financial Secretary, Yorkshire Area.
Mr. J. Smart, Area Agent, Yorkshire Area.
Mr. A. Hepworth, Chief Administration Officer, Yorkshire Area.
Mr. K. Saunders, Mining Engineer.
The National Association of Colliery Overmen, Deputies and Shotfirers.
Mr. C. Woods, Agent, Yorkshire Area.
Mr. G. Fellows, President, Yorkshire Area.
Mr. H. Gregson, Consulting Mining Engineer.
Mr. L Wormald, General Secretary, Yorkshire Area and National President.
The National Association of Colliery Managers Ltd., and The British Association of Colliery Management.
Sir Andrew Bryan, Consulting Engineer.
Mr. C. Alexander, President of the British Association of Colliery Management.
Inquiry findings ( of J.W. Calder, C.B., O.B.E., B.Sc., C.Eng., F.I.Min.E.
Chief Inspector of Mines and Quarries).
Seven men lost their lives as a result of an inrush of water at the face of South 9B district in the Flockton Thin seam.
The conditions in the district following the incident were such that only one body could be recovered.
Access to the face was not possible but I am satisfied that the evidence given at the Inquiry was sufficiently comprehensive to enable me to determine the causes and circumstances of the inrush.
Contents
Description of the Colliery.
Lofthouse Colliery in the North Yorkshire Area of the National Coal Board.
Situated some 2½ miles north of Wakefield, on the western fringe of the working coalfield.
Production began in 1877.
At the time of the inrush saleable output was 18,500 tons per week.
837 men employed underground.
207 on the surface.
There were 4 shafts.
At Lofthouse.
(1) A (downcast) 18 feet 6 inches in diameter. Used for coal winding.
(2) B (upcast) 15 feet diameter. Used for man winding.
At the top of B shaft were three Aerex fans in parallel extracting 180,000 cubic feet of air per minute at 7 inches of water gauge.
At Wrenthorpe. (some 1Ύ miles south).
(3) Silkstone (downcast) 14 feet diameter. Had winding equipment.
(4) Beeston (upcast) 14 feet diameter. Had no winding facilities.
A Keith Blackman centrifugal fan extracted 60,000 cubic feet per minute at 3.2 inches water gauge from the Beeston shaft.
Electric cap lamps in use, with flame safety lamps issued as firedamp detectors. Some officials used methanometers.
Management.
Acting Area Manager,
.T. Wright.
Deputy Director (Mining),
..G. Hayes.
Chief Mining Engineer
W. Forrest.
Deputy Chief Mining Engineer
(Mine planning and Surveying)
..R.P. Hollis.
Production Manager
T. Donnelly.
Colliery Manager
..T. Mapplebeck.
There were two Undermanagers, D.H. Bennett and W.H. Storey. Bennett had statutory responsibility for the Flockton seam, although in practice this had been transferred to Storey who in turn had been succeeded through local arrangement by J. Oliver in mid-February 1973.
Coal was worked by longwall advancing mechanised faces.
Seams worked.
Flockton Thin
..three working faces.
Eleven Yards
..
one working face.
Beeston
two working faces.
Development was taking place in the Blocking Bed seam which lies between the Eleven Yards and Beeston seams.
Very little water was pumped from the mine. The main make at the Lofthouse (A and B) shafts was from the old Haigh Moor workings, between 160 and 230 gallons per minute dependant on the season.
At the Wrenthorpe shafts there was a well shaft 63 feet deep, from which 33 to 55 gallons per minute were pumped (dependant on seasonal variation).
The make of water from the main shafts at Wrenthorpe was only 15 gallons per minute pumped from the Silkstone pit bottom.
South 9B District.
South 9B District is situated in the Flockton Thin seam to the west of the South 4 loader gate.
The face was 5,600 yards from Lofthouse pit bottom.
The Flockton Thin seam is 34 inches thick, including a 3 inch dirt band.
The roof is a medium grey shaley mudstone. The floor also consists of mudstone.
The face lies some 220 yards below the surface. Two seams above it were worked 120 to 130 years ago.
They were the Gawthorpe, (Warren House), at a depth of 50 yards, and the Top Haigh Moor at a depth of 120 yards.
The Silkstone seam about 80 yards below the Flockton Thin was worked around 1914.
Access to the South 9B district from South 4 loader gate was gained by a cross measures intake drift dipping at 1 in 6 through faults of 48 feet vertical displacement.
A 216 yards long single unit conveyor face was formed in the seam, with the return airway connected by an overcast to a roadway leading to the Wrenthorpe shafts. A slit at the air crossing, with two wooden airlock doors, provided a connection between intake and return.
Production commenced in December 1971. Working three shifts a day, using a double ended conveyor-mounted trepanner taking the full thickness of the seam plus 2 inches on floor dirt. The web was 26 inches; average weekly advance was 20 yards.
The face had gone to the rise at 1 in 24 for 1,060 yards when the inrush occurred.
The main gate had an advanced heading 4 feet 6 inches high; 18 to 25 feet ahead of the face line and a stable at the same height extended 12 feet along the face.
At the tail gate there was an 8 feet long stable at seam height.
Rigid bars and hydraulic props were used in the roadhead areas and powered supports throughout the face.
Both gates were formed by conventional ripping and packing; the main gate supported by 10 feet wide by 8 feet high arch girders set 3feet apart. The tail gate was supported by 8 feet wide by 7 feet high arches.
The district was ventilated by a separate split giving an air quantity of 11,700 cubic feet of air per minute on the face.
Methane drainage was practised from the tail gate with holes 120 feet long spaced at 120 feet intervals at right angles to the gate and inclined at 45 degrees over the waste.
The state of the district before the incident.
Methane content in the return air at the statutory measuring point was about 0.3 percent. The amount of water was small.
Systematic pumping was unnecessary.
Although there was a small fault on the face 80 yards from the main gate and weight breaks were evident from time to time. The roof was well controlled by the five legged powered supports.
Work on the afternoon shift of the 20th. March was normal and operations ceased as usual at 7.30 p.m., the trepanner had taken two webs and was at the tailgate end.
Night shift of 20/21st. March 1973.
E. Finnegan, the deputy made a pre-shift inspection stating in the tail gate, he reported to B. Oldroyd, the overman, when they met in the main gate at about midnight, that the face was normal.
27 Men were in the district on this shift.
Tail gate roadhead: -
4 rippers, 2 stable hole men, 1 shotfirer.
Face near the machine: -
4 men, 1 deputy.
40 yards towards tail gate
1 electrician.
Main gate roadhead area: -
2 men in advanced heading.
1 supports man in the stable.
4 rippers, 1 shotfirer near the ripping lip.
At the stage loader: -
1 overman.
1 fitter.
Conveyor roads: -
4 transfer point men.(2 in South 9B main gate, 2 further outbye).
Work then started on coal filling, advancing the heading and stables and ripping both roadheads.
At about 2.00 a.m. the trepanner had cut to No. 60 powered support, about 70 yards from the main gate.
The trepanner and face conveyor stopped because large stones were being broken up at the main gate roadhead.
The face conveyor never restarted.
The inrush was sudden and violent, water flowed in both directions along the face.
Contents
The Inrush.
At approximately 2.00 a.m., the T. Denton, the electrician, was travelling the face from the tail gate examining the power loader cable near mid face.
He heard a 'bang', he looked up and saw water flowing towards him from the direction of the trepanner.
He made his way immediately to the tail gate. The water was at conveyor height, about 7 inches, flowing along side him.
Those in the tail gate roadhead knew something was amiss, R. Barrett, the shotfirer attempted to contact by telephone anyone who might be available; he got no reply.
Also at about 2.00 a.m., B. Kus was in advance of the face in near the main gate roadhead when he heard a rumbling noise, looked along the face and saw lights (about 30 yards away).
He then heard a 'loud crack' and saw his workmates at the roadhead start to run outbye, he shouted a warning to C. Barnaby who was in the advanced heading.
As Kus made his way out past the ripping lip he was overtaken by a wave of water at the full height of the seam that knocked him against the side of the road. He dragged himself upright and ran outbye.
Oldroyd, the overman, at the stage loader, heard a 'heavy rumbling noise' and thought the ventilation had reversed.
He saw the main gate men running towards him and heard someone that water had broken in.
He tried without success to contact the face men over the loud hailer system. The water was at knees height in the main gate and he hurried outbye to the conveyor transfer point. He tried to phone the surface but was unable to do so.
He then tried to ride out on the gate belt but it stopped almost immediately so he jumped off and ran. He passed C. Cotton, a main gate ripper, and made his way to the top of the 1 in 6 drift. He again tried to contact the surface. Eventually he succeeded in doing so from the South 4 loader.
K. Stone, a fitter, who had travelled along the face with the trepanner to No. 60 powered support, was at the main gate roadhead when warned water had broken in. He ran outbye and when passing 9 South C development heading he looked in but saw no one.
Stone switched off the electric power to the development and continued outbye passing S. Wojeck, the conveyor transfer point attendant, at the outbye end of the gate.
He continued outbye and switched off the electricity supply to the main gate at the transformer house at the overcast, then ran to the top of the 1 in 6 drift. He picked up the telephone and found Barrett the South 9B tail gate shotfirer on the line. He told Barrett, who was still at the inbye end of South 9B tail gate, what had happened and was advising him to withdraw his men when Willoughby the main gate shotfirer arrived, took the telephone, and told Barrett to withdraw his men immediately.
Barrett's conversation with Stone and Willoughby took place some time after his earlier unsuccessful attempt to make contact by telephone but, in the interval, no men had come off the face.
Barrett replaced the telephone and instructed Denton to cut off the electrical supply to the face. G. Firth, the tail gate stablesman, went back and looked along the face but could see nothing; then all the men in the tail gate made their way outbye.
This party of 8 men reached the slit at the air crossing, Denton opened the first door and saw the second door was bulging towards him with dirty water seeping through it. He retreated to the return and the party then travelled over the air crossing through South 9B gate and ultimately to South 4 gate.
Had they delayed a little longer this escape route would almost certainly have been blocked. Subsequently a check was made by Willoughby on the number of men who had escaped to the South 4 gate.
At approximately 2.35 a.m., K. Furniss, the night shift overman, who was in the pit bottom, was told from the surface control room that water had broken into the South 9B district. He gave instruction for the manager, the assistant manager and Wakefield Rescue Station to be contacted.
Furniss was later instructed by T. Mapplebeck, the manager to return to the surface to check on the number of men missing.
It was established that Frederick William Armitage, Frank Billingham, Sydney Brown, Alan Haigh, and Edward Finnegan, (last known to be working the South 9B face line).
Colin Barnaby, (in the advance heading when the inrush occurred).
Charles Cotton, (last seen making his way outbye down the main gate).
were missing.
The emergency procedure was instituted by the manager shortly after 2.35 a.m., and a telephone call was received at Wakefield Rescue Station at 2.45 a.m.
Led by W. Cave, a member of the permanent rescue brigade, the first team went below ground to the South 4 gate then to the 1 in 6 drift, where at 4.15 a.m., the water was seen to be blocking the roadway 60 yards from the drift top.
The team then travelled towards South 9B district by the return airway where, at the junction with South 9A return, the roadway was also blocked with water.
This inspection proved South 9B was completely sealed off.
Contents
Rescue and Recovery.
The rescue attempt.
People at the colliery: -
T. Wright, acting Area Director and his senior officials.
A. Harley, H.M Senior Inspector of Mines and Quarries, and a member of his staff.
N. Siddall, The National Coal Board's Member for Mining.
After assessing the situation it was decided to install pumps in the 1 in 6 drift to lower the water and regain access to the district.
It was also decided to install a submersible pump in the Silkstone shaft at Wrenthorpe as it was apparent the water would drain to this point.
Alternative methods of rescue were discussed and a decision to bore from the surface to South 9B tail gate was made.
The bore hole, intended to be about 6 inches in diameter when it reached the roadway was commenced 11.15 p.m., about 21 hours after the inrush occurred.
The operation involved dismantling, transporting, and re-building a large drilling rig.
A surface visit was made to the site of the Old Low Laithes Colliery ; it was found the Bye Pit was exposed and water could be heard falling down it.
Before mid-day it was reported that the Engine Pit and Bull Pit were exposed and water could also be heard falling down them.
There was little doubt that there was a direct relationship between the inrush of water into the Lofthouse workings and the water pouring down the old shafts.
A decision was made to seal and fill them.
Hardcore, baled straw and clay were used to obtain a water-tight seal near the bottom and filling to the surface was completed with hardcore.
This work was finished by 11.30 p.m. on 23rd. March as was the filling of a large depression between the Engine and Bye Pits.
After filling had commenced, the Bye Pit was plumbed and found to be 541½ feet deep to the top of the filling. The depth was later calculated to be about 660 feet.
At Lofthouse little progress in pumping water from the 1 in 6 drift was being made.
Late in the afternoon of 21st. March it was decided that a mines rescue team from Hednesford, Staffordshire, should make a trial dive for 25 yards. (the members of the team had been specially trained as frogmen).
This was carried out during the evening; the water was too badly fouled, opaque and full of material in suspension to risk a longer dive.
On the 23rd. March after the level of the sludge had been lowered, frogmen were again used in the 1 in 6 drift, near the air crossing, in an attempt to locate the slit between intake and return. The conditions were too difficult and the attempt was abandoned.
Several pumps were coupled into various pipe ranges, difficulties arose and progress was slow due to the high proportion of solid material in the fluid.
Work began, (24th. March), on a small 'piggy-back' roadway over the arches at the foot of the 1 in 6 drift to gain access to the slit and tail gate over the wooden doors.
When this was done on the 26th. March, work was suspended on the surface borehole.
At 10.20 a.m. on the 26th. March the Lofthouse Colliery No. 2 rescue team started from the 1 in 6 drift to inspect the South 9B tail gate.
Passing through the 'piggy-back' roadway, the team dropped into about 4 feet of sludge and water, which persisted for some 30 yards, after which it was possible to travel up the tail gate without hindrance.
Five yards beyond No. 20 methane drainage hole there was silt and rubble reaching to about 3 feet 6 inches from the roof.
The team crawled on top of this for a further 44 yards to a point, 1,067 yards from the air crossing.
Further progress became impossible.
The team took air samples at approximately 160 and 760 yards inbye of the air crossing.
When analysed, the first contained 6 percent methane, 13 percent oxygen, and 4 percent carbon dioxide. The second contained, 31 percent methane, 6.6 percent oxygen, and 2.9 percent carbon dioxide.
The air would not have sustained life.
J. Coxon, the Area Chief Scientist, said although the sample amounts were small
The oxygen analyses were accurate.
At 12.45 p.m. a Glasshoughton Colliery rescue team attempted to explore the intake roadway beyond the slit. There was water and sludge within one foot of the top of the arches at the slit junction, after a few yards the underlying sludge became very soft.
The team sighted a body some seven yards further inbye before they withdrew. Later that day R. Williams, H.M. Inspector of Mines and Quarries, recovered the body. (identified as Charles Cotton).
On March 28th. at about 10.00 a.m., A. Rollinson, an assistant superintendent at the Rescue Station in Doncaster, made an assessment of exploring along the intake gate inbye the slit junction. The water level was within 14 inches of the roof at the outbye end, but he found that conditions improved inbye.
At 11.33 a.m. the Ledston Luck Colliery rescue team carried out an exploration and after some difficulty at the transfer point travelled 490 yards beyond it. Samples were taken at that point, when analysed they contained 26.2 percent methane, 9 percent oxygen, and 1.3 percent carbon dioxide.
Subsequently, the Savile Colliery rescue team made an inspection along the same route, and after encountering a number of small obstructions found the road blocked with debris at about 917 yards inbye.
At 6.25 p.m. on the same day the Walton Colliery rescue team travelled inbye to the South 9C development heading and examined it completely.
No survivors were found on any of these explorations and after consideration of the air sample results and the reports of the team captains it was agreed by representatives of all the interested parties that there was no further hope of finding anyone alive.
Contents
Recovery of the District.
As part of the rescue operation auxiliary ventilation, a power supply and pumping equipment had been installed in old South 9 and South 9A main gates to remove water and restore a ventilation circuit as far as the air crossing at South 9B tail gate. This was finally achieved when water blocking a swilley in old South 9A main gate was removed on March 28th.
The removal of the sludge at the foot of the 1 in 6 drift enabled auxiliary ventilation to be installed in both the South 9B gates by rescue teams wearing breathing apparatus but, because of the very high methane concentration in the gates, this work could not be hurried and was not completed until 17th. April.
The rescue attempt and the recovery operation took place in conditions of extreme difficulty and discomfort.
Despite the arduous periods of duty and disappointments that followed their valiant efforts, the rescue workers demonstrated throughout the admirable qualities characteristic of the Mines Rescue Service.
On 18th. April both gates were inspected in fresh air by H.M. Inspectors, Mapplebeck, the manager, and P. Wood, the surveyor, accompanied by a National Coal Board photographer.
It was noted that the water level in the 1 in 6 drift had been 18 feet above the floor level of South 9B crossgate, so that the roof of the intake at its lowest point would have been submerged to a depth of 10 feet.
An accumulation of silt and debris had gathered at the bottom of South 9B main gate were the water level had reached to within 1 foot 3 inches of the roof.
Throughout the main gate marks were observed on the sides of the roadway, which indicated that water had flowed down the gate at a depth of about 2 feet 9 inches but had been deeper in places where localised blockages had occurred.
Mud and debris, which had been carried down the gate by the water, contained pieces of broken pottery, the remains of old footwear, bricks, dressed sandstone blocks and old mining timbers which included segments of shaft cribbing.
The cribbings were of a size corresponding to a shaft about 9 feet in diameter. A build up of debris commenced at a point 894 yards inbye, where the water mark was at roof level, and 23 yards further inbye the road was completely blocked by a fall.
In the tail gate, the slit had been filled with mud and silt to a depth of 5 feet but 50 yards inbye the road was clear. There was evidence that water had flowed down the gate at a consistent depth of about 12 inches and the floor had been washed clean.
827 yards inbye the air crossing the first evidence of foreign material was observed. From this point parts of old shaft cribbings, bricks and sandstone blocks were seen. Debris had accumulated from 1,017 yards inbye and at 1,067 yards was only 3 feet from the roof. A fall had occurred at this point and it was not possible to go any further.
The following day representatives of the interested parties made an inspection of the district. Mapplebeck, in evidence spoke of the violence of the inrush and stated that water was still seeping through the debris that blocked both roadways at the time of the inspection. He also spoke of the artificially low level of the surface water table after the incident and referred to the possibility that the natural restoration of the water in the strata and old workings would impose an increasing hydrostatic pressure on the debris which blocked South 9B face and the inbye ends of the main and tail gate.
Because of the opening up of Bye, Engine and Bull Pits to the surface, the flow of water down these shafts, and the old shaft lining material found in the district after the inrush, there was no doubt that physical connection had been made between South 9B face, at or near the trepanner, and old workings in the Flockton Thin seam from one or more of the old shafts.
All concerned considered these factors, and it was realised that any attempt to recover the bodies would necessitate clearing the debris from the gates and face and would invite the possibility of further inrush.
It was decided the risk was too great.
Contents
Mr. Calder's Observations.
Much of the evidence presented at the Inquiry was concerned with factors that might have been interpreted as indications that old workings were being approached and that the possibility of an inrush could have been foreseen.
These were: -
(a) Water in South 9B district.
(b) The presence of water in shotholes.
(c) The smell in South 9B district.
(d) The subsidence at the Bull Pit in September 1972.
(e) Plans and records available.
Water in South 9B district.
A number of witnesses commented on the presence of water in the district in the weeks prior to the inrush and it seems probable that there was an increase in the amount coming through the strata.
It was evident, however, that the amount of water was too small to require systematic pumping and water was never more than a nuisance.
Men who work in the same district every day are not readily disturbed by minor changes which can be easily interpreted as being brought about by the use of dust suppression water or by leakages in water ranges and hydraulic hose pipes.
Similarly, officials may well come to accept that a slight increase in water is the result of natural geological disturbances or breaks in the strata caused by interaction. Someone less accustomed to such minor variations may well have been disturbed or possibly 'perplexed', as was in the case with Oliver who had only recently taken over responsibility for the district.
Rapid face advances allied to the mining of large tonnages of coal tend to mask the presence of water and in this case the face advanced approximately 40 yards in the fortnight before the inrush.
Because of this any warning signs that danger lay ahead were not impressive enough to be properly understood in the time available.
The presence of water in shotholes.
Evidence was given about the presence of water in shotholes drilled in the South 9B district during the weeks preceding the inrush. The occurrence varied from water filling some holes if bored downwards to a slight trickle if a hole was incline upwards. This is not unusual in many coal seams and the phenomenon had, in fact been observed elsewhere in this seam. No significance was attached by the officials to the appearance of water in this way.
The smell in South 9B district.
Smells are common when minerals are worked and many coal seams and even individual districts have an odour that is peculiar to them. Sulphurous smells are not uncommon where bands or even lenses of pyritic material are broken by coal cutting.
Persons who are regularly exposed to such smells become accustomed to them and lose their ability to identify changes in intensity.
The response of witnesses to persistent questioning about the unpleasant smell in the district appeared to be inconsistent and this may have been because of the stress placed on identifying it with the smell of 'rotten eggs'.
However, there would seem to have been two smells in the district, one associated with the cutting of coal on the face and the other associated with water welling through the strata.
It is unlikely that workmen who have been exposed to a particular smell for a long time will suddenly complain about it and the complaints almost certainly arose from the different smell coming from the water percolating through the strata.
In the circumstances it is hardly surprising, however, that their complaints, perhaps tentatively expressed, were not considered significant by officials familiar with the odour of the Flockton Thin workings.
Subsidence at the Bull Pit in September 1972.
Many old shafts have not been completely filled in with debris but are only filled above wooden platforms sited a short distance below the surface.
Variations in the level of the water table caused by the weather can have a considerable effect on the fill material, and in time, wooden platforms rot away.
This could explain the subsidence at the Bull Pit in September 1972.
The Flockton Thin seam workings were 350 yards away at this time, and would not affect the shaft or its filling.
Plans and Records available.
At no time during the Inquiry was any documentary information produced to show that the workings existed in the Flockton Thin seam in the vicinity of South 9B face. The only plans of the area, which were available, were old estate plans, not certified and likely to be incomplete and unreliable.
The information available, the efforts made by the surveyors to find out all that they could about workings adjacent to South 9B district and the decisions which they reached are described in the following paragraphs.
Contents
Managerial Functions.
The planning procedures and the investigation for the proposed development of South 9B district.
The planning procedures were outlined by R.P. Hollis, he said a set of plans were prepared for each colliery showing the proposed workings for 5 years ahead.
The plans indicated surface features and other matters of particular interest.
E.R. Radcliffe, the senior surveyor, commented on the nature of the investigations into the development of a new face.
'I start off with a surface plane. I then investigate the plan in the following manner, and these are not necessarily in order of importance:
Surface inspection to ensure that all properties likely to be affected are shown on the plan;
Visits to the local authority offices to find the lines of public utility services - gas, water and electricity;
That all is working right in respect of leases governing that particular area:
The old workings shown on the plan either above or below.
If it is a new area I ask the colliery surveyor to make a composite plan, which is done on a transparency, which can be fitted over that particular plan which shows every seam that has been worked in that area. These are built up and taken from every plan that we have in our possession. And again, if we have not got them, plans in the catalogues of plans of mines. We then look at the geological sheets and check these.
We put all the old shafts which are recorded: adits if necessary, opencast sites with areas of backfill, with information either in a report or on the plan relative to those particular items'.
L.J. Mills, Area Director when the district was planned, said in evidence that shortly after becoming director he formalised this planning procedure by instituting a system of signatories, and by causing a summary report to be made and attached to the plan for the information of the signatories.
For the area worked by Lofthouse Colliery there were available to the surveyors old estate plans that were kept at the colliery. These plans showed old workings in the Gawthorpe and Haigh Moor seams in the Low Laithes area and also the locations of some of the old shafts from which these seams had been worked during the 19th. Century.
They were not the abandonment plans required by law after 1873, and were not complete. They did not show the depth of the shafts.
On October 8th. 1970, in the course of this investigation to ensure there was no danger from old workings, Wood, the colliery surveyor, made a visit to the Mining Records Office at Rawmarsh, near Rotherham, to inspect the abandonment plans. He inspected all the available abandonment plans relative to the area of coal proposed to be worked by South 9B face and found no evidence of any workings in the Flockton Thin seam or of old shafts sunk below the Haigh Moor seam.
At the North Yorkshire Area headquarters of the National Coal Board there was the journal of Sinkings and Borings, collected by Joseph Tolson White, a mining engineer well known in Wakefield in the 19th. Century.
This journal gives detailed sections of a number of mine shafts and boreholes in the Yorkshire coalfield starting with the Bye Pit at Low Laithes Colliery.
Both Wood and Radcliffe examined this journal and paid particular attention to the Low Laithes Colliery Bye Pit log. They formed the opinion that the log showed the Bye Pit to be sunk to the Haigh Moor seam with a borehole below this through the Flockton Thin seam to the Silkstone seam.
Both men agreed under examination, that there was another possible interpretation. In this connection the evidence given by E.H. Francis, the Assistant Director of the Institute of Geological Sciences, Leeds, is important. He said that while there is a broad standard for recording information from sinkings and borings in a notebook, there can be individual idiosyncrasies.
On examining, in the witness box, the record made by Tolson White of the sinking and boring at the Bye Pit, he said that in the light of his considerable experience in the coalfields, although not specifically in Yorkshire, he would have inferred that the borings started where the log was given in detail and in colour.
In reply to later questions he agreed that there were inconsistencies in the colouring of various boring and sinking sections and that he could not say with certainty where the sinking ended and the boreholes started.
Mr. Calder (who complied this report), found it significant that his (Mr. Francis's), impression on seeing the journal for the first time (when he entered the witness box), was that the shaft was sunk to where the coloured detailed section commenced at the Flockton Thin seam horizon at a depth of 218 yards.
The surveyors, in furtherance of their investigation of known old shafts in the Low Laithes area, also paid a visit to the Institute of Geological Sciences at Leeds. This visit was in September 1970 by appointment, which Radcliffe made by telephone.
There is a conflict of evidence as to whether Wood and Radcliffe saw a qualified geologist at the institute; this matter was not resolved. However it is clear that Wood and Radcliffe inspected the hand engraved plan from which the 1878 edition geological map was produced, A.H. Green's geological field slip and Geological Survey Sheet No. 94 shows a section across the Yorkshire coalfield passing through the Bye Pit. They also saw the field slip used in the geological survey for the 1932 publication of the geological map.
Green was a geologist employed by the Ordinance Survey in the middle of the 19th. Century. In examining the field slip Wood and Radcliffe did not attach any significance to the reference X111 p. 74 marked alongside Averthorpe Colliery and at Barron's Pit. Although Green cross-referenced his notebooks and page numbers on his field slip both surveyors said in evidence that they did not know this and had not heard of Green's field notebooks prior to the inrush.
The geological section, of which they already had a copy, shows the Bye Pit sunk as far as the Haigh Moor seam and it does not show the borehole recorded by Tolson White. Francis, in commenting on this, made the following significant remarks:
'There has been an implication that I would like to correct, sir, that because a geological section shows a pit or borehole like this with its bottom at any particular level that it is definitive. What I want to say is that geological maps and sections are designed to show geology, and mining data which goes on to maps and sections in general are put there to illustrate the geology, so that the geological map is not a precise catalogue of mining. It attempts to be a good catalogue of the rocks, but it is in no way - I say this as a warning to mine people who may be listening - they should not regard mining data put on a geological sheet as definitive data for mining purposes. The sheet is intended for geological purposes'.
The two surveyors left the Institute of Geological Sciences with no more information than they already possessed in the Geological Memoirs of 1878. They had satisfied themselves that there was no further relevant information available and were convinced that the shafts only went down to the Haigh Moor seam, with a hole bored below the Bye Pit through the Flockton Thin seam to the Silkstone.
They constructed the development layout plan and placed a 50 yard warning line round the Engine pit and Bye Pit setting the face line to keep clear of this line. On the plan alongside the protective pillar thus formed Radcliffe placed the comments:
' Bye Pit believed sunk to Haigh Moor seam at 141 yards deep and bored to Silkstone seam at 302 yards deep. Flockton Thin seam at 219 yards deep'.
It was in this form that he signed the layout plan on 4th. August 1971 and initiated its progress through the chain of planning responsibilities.
As already stated the surveyors were completely unaware of the existence of Green's field notebook No. X111 with the entry on page 74 which states:
'Low Laithes Colliery: Sunk 80 yards below Haigh Moor and bored 38 yards lower at the Bye Pit.
Had they seen this entry when they visited the Institute they might have altered their interpretation of the Tolson White log of the Bye Pit. As it was, the entry did not come to light until after the accident when a member of Francis' staff, a qualified geologist with many years of service in the Yorkshire coalfield, was instructed to search for the records and found it from a reference on the field slip.
I must emphasise that in his evidence Francis said that some of the less experienced members of his staff could very well have failed to appreciate the significance of the Roman numerals on Green's field slip.
While it can only be conjecture, I (Mr. Calder), consider that Green did not have direct information about the Bye Pit and did not transfer the information on page 74 of field notebook No. X111 to the slip because he was in some doubt as to its accuracy.
It is a matter of concern, however, that the evidence available to the surveyors in the Tolson White journal did not raise sufficient doubt in their minds about the depth of the Bye Pit for the matter to be brought to the direct attention of their superiors in the chain of planning responsibility.
No plans showing old workings in the Flockton Thin seam were found before the inrush and, despite an intensive and widespread search none has been found since; but it had been suspected that the Bye Pit was sunk to the Flockton Thin seam the collective opinion of mining engineers might have been that the utmost care was necessary as there was, at least, a possibility that the Flockton Thin seam had been worked.
The layout plan constructed by Radcliffe was approved by Mapplebeck, the manager, then sent to Hollis, the Deputy Chief Mining Engineer (Planning and Surveying), together with a summary report, prepared in the planning department, which stated that the Gawthorpe and Haigh Moor wastes were probably water logged. Hollis discussed the report and plan with Radcliffe and the senior planner for the group of collieries in which Lofthouse was included and accepted the information provided.
He did not see Tolson White's sinking and boring journal and although evidence was given that it was discussed there is no reference to it in the summary report.
Having satisfied himself by these discussions, Hollis, the first person in the chain of command to carry responsibility under Section 1 of the Mines and Quarries Act 1954, signed the plan.
W. Forrest, the Chief Mining Engineer, who signed it on the following day, relied on the information supplied to him in discussion with Hollis and did not see the Tolson White journal.
One week later T. Wright, the Deputy Director (Mining), signed the layout plan. He did not see the Tolson White journal and was unaware of its existence at that time. He said in evidence that it was his usual practice to discuss new developments at quarterly meetings.
Finally, a week later Mills, the Area Director of the North Yorkshire Area met Hollis and discussed the layout plan. During the meeting the summary report was discussed and reference was made to the geological Memoirs of 1878.
Mills was told of the boring journal but did not examine it and he signed the layout plan, which was then cleared for work to commence.
The summary report was a bald and restricted statement in which no attempt was made to present the documents investigated by the surveyors. It did not review the thinking, which had influenced the acceptance or rejection of evidence which required interpretation.
None of the persons who held Section 1 responsibility saw, or examined, any of the information used by the surveyors in coming to their conclusion that the Bye Pit was sunk only to the Haigh Moor seam and, in particular, no one other than the two surveyors examined Tolson White's journal.
The senior signatories relied entirely on the summary report and oral assurances that all the necessary basic facts of the investigation had been properly ascertained and considered.
None of these discussions or meetings was minuted.
Contents
Precautions against external dangers to workings.
Section 75 of the Mines and Quarries Act 1954 states:
'(1) In the case of every mine, the owner thereof and the manager thereof shall be charged with the duty.
(a) of taking such steps as may be necessary for securing that he is at all material times in possession of all information which indicates or tends to indicate the presence or absence, in the vicinity of any workings carried on or proposed to be carried on in the mine, of:
(i) any disused workings (whether mine workings or not);
(ii) any rock or stratum containing or likely to contain water (whether dispersed or in natural cavities);
(iii) any peat, moss, sand, gravel, silt or other material that is likely to flow when wet;
and
(b) of taking such steps as may be necessary for the purpose of substantiating any such information which comes into his possession (whether in consequence of the discharge of the duty imposed upon him by the foregoing paragraph or not).
(2) In the case of every mine, the owner thereof and the manager thereof shall each be charged with the duty:
(a) forthwith after any such information as is mentioned in paragraph (a) of the foregoing subsection comes into his possession (whether in consequence of the discharge of the duty imposed upon him by that paragraph or not), of furnishing to the other particulars of the information;
and
(b) forthwith after taking any steps in discharge of the duty imposed upon him by paragraph (b) of the subsection, of furnishing to the other particulars of the steps taken and of any conclusion reached as a result of taking them.'
I (Mr. Calder), have already mentioned that even after a thorough search no plans of old workings in the Flockton Thin seam in the vicinity of South 9B district were found after or before the inrush. I consider, therefore, that in the light of the information available to them when the layout plan was prepared and approved, Mills and Mapplebeck were justified in thinking that they had discharged their duties under this section of the Act.
However, Mills said at the Inquiry that had he been aware of all the information he would have been very hesitant about working coal in the Low Laithes area and that a considerable amount of doubt has been sown in his mind as to the Flockton Thin seam as a whole.
The approach to the Institute of Geological Sciences.
Francis outlined the alterative ways in which it was possible to obtain information from the Institute namely,
(i) A written request for information relating to a specific area. This would receive a written reply which would be recorded in the Institute files.
(ii) A telephone conversation or pre-arranged personal interview with a particular geologist who would then prepare a memorandum of the conversation which would be placed in the appropriate file.
(iii) A visit to the Institute library, which is open to the general public, where the inquirer would make his own investigation. No record, other than entry in the visitors book would then be made. The librarian is instructed to ensure that if geological information beyond the competence of the library information service is sought, the inquirer is to be referred to the relevant district geologist who would then prepare a memorandum of the interview and place it in the file.
Francis was of the opinion that the first two methods would be the most likely to reveal obscure information and emphasised that a written inquiry would receive the most thorough and comprehensive investigation. The success of a casual personal call would depend on the experience of the members of staff available in the office at the time of the call. National Coal Board officials in Yorkshire have used all three methods of approach from time to time.
However, in recent years there appears to have been a change in the method of approach to the Institute for information and very few written requests have been received. It is apparent that, all approaches to the Institute of Geological Sciences for information about old mines or plans should be supported by a written request.
The appointment of undermanagers.
The requirements of Sections 6(6) and 15 of the Mines and Quarries Act 1954 regarding the appointment of undermanagers have never been in question but the Inquiry revealed that Bennett, the appointed undermanager of the Flockton Thin seam, was replaced by Storey under a local arrangement without formal notification to the Inspector for the District. Later the undermanager's duties for South 9B district were similarly transferred to Oliver, who believed the he was the statutorily appointed undermanager, and accepted all the duties and responsibilities implicit in such an appointment.
The suitability of Story and Oliver for statutory appointment is not in question and the omission had no bearing on the standard of supervision at undermanager level, but the Act requires these appointments to be notified to the Inspector so that there is no doubt as to who holds the responsibilities placed on an undermanager by the Act and the Regulations.
Withdrawal of men following the inrush.
When the inrush occurred all production operations which used the main access routes to the South 9B district were suspended and the men withdrawn to the surface but production in the other parts of the mine continued.
While this did not contravene the Regulations it was not in keeping with the spirit of the requirements for safety in mines.
Withdrawing men from inbye positions and winding them to the surface takes time and should be commenced as soon as possible to avoid the difficulties likely to be created by a major incident.
Contents
Other Matters.
(Mr. Calder's comments on matter considered at the Inquiry and relevant to the inrush, the post inrush phase and means of avoiding future occurrences).
The Coal and Other Mines (Precautions Against Inrushes) Regulations 1956.
Reference was made to these Regulations and, in particular, to Regulation 4 which limits the width of any working approaching and within 40 yards of any place containing or likely to contain an accumulation of water, to a maximum of 8 feet and which requires advance and flank boreholes.
These precautions were not taken since the existence of old workings was not suspected, but it was suggested by some witnesses that Regulation 4 should be amended to allow sufficient width for modern high speed coal heading machines to operate and to accommodate drilling machines capable of boring long holes through the measures.
Special Regulations can be established to allow a greater width of working place should this be justified and I consider, therefore, that it is not appropriate at this stage to change the Regulations relating to precautions against inrushes.
Telephone systems.
The main telephone system at Lofthouse was installed in 1967 and was of modern design. South 9B district was equipped with five auto magneto telephones which were sited at:
(a) the South 4 transfer point.
(b) The face end of the tail gate.
(c) The main transfer point.
(d) The conveyor tandem transfer point.
(e) The stage loader in the main gate.
The five telephones were all connected on a single line to an automated telephone exchange at the surface. For emergency purposes a manually controlled switch board was provided on the surface so that calls from selected telephones could be connected when required to the Post Office telephone network.
There was also a separate loud speaking communication system installed throughout the length of the face with additional telephone units at the main and tail gate roadheads. Communications between the face system and the main telephone system could be established through a special manually operated coupling link located at the stage loader telephone.
Prior to the inrush the telephone system was functioning correctly apart from a loss of volume on the face loud speakers. The inrush must have put the face telephone system out of action but the auto magneto telephones continued to function and Barrett at the tail gate roadhead was given warning to withdraw his men by Stone and Willoughby speaking from South 4 transfer point.
The principal disadvantage of the main telephone system was that, with five instruments on the one line, calls to other extensions could not be made if one of the telephones was in use, or if a handset was left off its hook or incorrectly replaced.
The lack of an overriding facility for use in an emergency and the need to turn the magneto for at least 4 seconds before a number could be dialled inevitably created difficulties for the men under the stress of an emergency.
Loud speaking telephones with an overriding facility to allow emergency messages to be broadcast are in the final stages of development for incorporation into existing systems and this development should be completed so that they can be brought into use as soon as possible.
Pumping solids in suspension.
Re-entry to the district was delayed because of the difficulty in dealing with the mud and sludge washed to the foot of the 1 in 6 drift. The particle size and proportion of solids made the mixture difficult to handle by the available pumps yet it was still too wet for handling by conventional mechanical equipment.
A considerable amount of development work is necessary if a method of dealing with mixtures of this nature is to be evolved. Nevertheless, the work should proceed and since the equipment, when developed, is unlikely to have everyday application it should be kept available at selected sires for use in case of emergency.
Communication with trapped miners.
A number of systems are being developed in several countries and the most promising seams to be that based on the use of portable 'walkie talkie' radio sets in conjunction with a transmission line. Two way speech communication can be established instantly to a base station and, if necessary, between individual sets provided that the requisite cable has been installed. Over short distances any insulated conductor of electricity is capable of transmitting signals. Seven pre-production sets of a British system are shortly to be installed below ground.
Monitoring of mine water.
Coxon, the Area Chief Scientist, in his evidence, spoke of the identification of mine waters by chemical analysis since there are frequent constituents, which provide a reliable, if not infallible, means of relating mine waters to seams or strata. Obviously mixtures of water cannot be reliably traced unless the constituents in the mixture have marked characteristics.
The technique for monitoring mine water is already used extensively in certain National Coal Board areas and has an application in most circumstances where water may be a hazard. Regular sampling and analysis might indicate a change of water source, which would justify thorough investigation.
Seismological techniques as alternatives to physical probing for shafts, old workings and similar underground cavities.
In most coal producing countries research has taken place in recent years on the adaption of seismological techniques to the location of geological abnormalities. Some of the earlier work on horizontal seismic reflection and refraction techniques gave inconclusive results, but more recently the National Coal Board, and Institute of Geological Sciences and certain private firms have pursued specialised concepts in an attempt to evolve wholly reliable systems.
Among the more promising developments are:
(i) the horizontal seismic reflection method using channel waves, developed by Dr. Krey, a European scientist, during his research work on seismology. He concluded that a coal seam would act as an energy channel which would result in waves being propagated in the coal seam. This concept has been taken up by the National Coal Board and both the theoretical and instrumentation aspects are being pursued to develop suitable techniques.
(ii) the high resolution vertical surface reflection seismic method tried experimentally with some success in the United States of America for the detection of old single seam workings at shallow depths. It involves the production of a 'synthetic' seismogram and experiments with this method at deep surface boreholes will be tried by the National Coal Board.
(iii) The inter borehole horizontal seismic work which is under development and field trail by the Institute of Geological Sciences and utilises a high energy 'sparker' source placed in a borehole to transmit repetitive signals to recording devices located in other boreholes. The geology between the boreholes is then developed from an interpretation of the velocities of the signal.
(iv) The vertical shallow surface seismic reflection method of Electrolocation Limited employing a traversing falling weight as the sound source. The signals at the geophones are recorded an reproduced, through a conversion device, as a record of the traverse in graphical form.
D.M. McCann, a Principal Scientific Officer at the Institute of Geological Sciences, Engineering Geology Unit, London, in evidence, reviewed these developments and it is clear that none of them is yet sufficiently advanced to be applicable to the detection of old workings. The severe limitations of range and the complications of interpretation were very properly stressed by McCann who said:
'I think you cannot interpret geophysical surveys, seismic refraction ones in particular, without control boreholes.'
Abandoned and disused mine shafts.
During the course of the Inquiry, were asked about locating and filling in old shafts and because of the wide public interest in the problem I allowed some time to be devoted to it. Unfortunately, because of the size and complexity of this problem there are no easy solutions.
Mining has taken place in Britain since the Roman times and it has been estimated that there are at least 80,000 old shafts, many of which are uncharted.
The only part of the Mines and Quarries legislation dealing with the problems of abandoned and disused mines is Section 151 of the Mines and Quarries Act 1954,
Which places a further duty on the owner of an abandoned or disused mine to ensure that the surface entry to every shaft or outlet is provided with an efficient enclosure, barrier, plug or other devices to prevent any person accidentally falling down the shaft or entering the outlet.
This provision extends to all mines abandoned since 9th. August 1872 and to any mine abandoned before then if 'by reason of its accessibility from a highway or a place of public resort, it constitutes a danger to the public'. It also provides that any such shaft or outlet not properly secured may be deemed a statutory nuisance under the Public Health Act 1936.
For the purpose of the Inquiry my interest in old shafts was confined to those in the vicinity of South 9B district whose existence was known and shown on the plans. Undoubtedly, each could have been precisely located and exposed at the surface, after which a borehole could have been put down through each in an attempt to discover the extent of filling and total depth. It might even have been possible to remove the partial filling and supporting scaffolds and completely fill the shafts with suitable material. Work of this kind is difficult and dangerous and, had it been undertaken, would not have given any indication of the existence or extent of old workings in the Flockton Thin seam. Successful filling might have reduce the magnitude and the violence of the inrush but this is problematical.
Contents
Mr. Calder's Conclusions.
(i) the disaster was caused by an inrush of water from old workings in the Flockton Thin seam into the South 9B face at a point between 30 and 70 yards from the main gate roadhead.
(ii) The old uncharted working probably originated from the Bye Pit, now known to have been sunk to the Flockton Thin seam, and the Engine pit of the long abandoned Old Low Laithes Colliery.
(iii) The magnitude and violence of the inrush were due to the shafts and associated wastes in the Gawthorpe and Haigh Moor seams being water logged over a considerable area.
(iv) The victims whose bodies were not recovered were probably killed instantly.
(v) Important decisions relating to the safe working of the mine were taken at the planning stage by surveyors and were accepted by the manager and the Section 1 appointees who did not call for and examine the supporting information.
(vi) The implications of the environmental changes which took place in the districts in the weeks prior to the inrush were not fully appreciated.
Mr. Calder's Recommendations.
(i) in planning for the extraction of an area of coal all the available evidence should be listed and attached to the layout plan. Minutes should be taken of all discussions and the final decisions should be recorded and should be taken by a senior mining engineer carrying appropriate responsibilities under Section 1 of the Mines and Quarries Act, 1954.
(ii) When an area of coal under consideration includes old shafts or workings prior to 1900, the utmost care should be taken during the preliminary investigation to ascertain their position and extent. In the absence of positive information the coal should not be worked.
(iii) Approaches to the Institute of Geological Sciences relating to areas of coal which are intended to be worked should be accompanied by a written request for information so that the full facilities of the Institute can be utilised.
(iv) The National Coal Board and the Institute of Geological Sciences should set up a small working party to consider the feasibility of preparing a catalogue of old geological field notebooks and other documents to ensure that these sources of information are not overlooked.
(v) A national appeal should be launched by the Department of Trade and Industry for old mining plans held in private hands to be made available for copying.
(vi) The development of equipment capable of handling fluids with a high solids content should be pursued.
Lofthouse Colliery. 1916. Courtesy Joe Stocks.
View Plan.
South 9B tail gate.
South 9B main gate.
Contents
|
