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Extract from HMI of Mines 1939
HMI of Mines Mr Frazer
Researched by John Lumsdon
Coal Dust Precautions
This section of the report is accompanied 8 photographs and a diagram which states: The approaching advent of new and more stringent regulations regarding treatment of coal dust makes a review of present practice important. When it is recollected that to dilute a combustible substance down to 25 per cent necessitates three times as much inert dust as to dilute it down to 50 per cent.
The tremendous amount of stone dust that would have to be purchased transported into the mine and distributed on the roads – unless other steps be taken to comply with the proposed new regulations will be realised.
Sooner or later this dust and the coal dust intermingled with it, must be swept up, filled into tubs and sent out of the mine again.
Economical Proposition
A successful home-made device applied to a gate-end loader is known as the “Smellie” dust precipitator. A jet of compressed air serves the triple purpose of sucking water from a storage tub, atomizing it and mixing the dust loading air, drawn from a hood over the loading point. Water consumption is about 60gallons a shift. Konimeter tests on the return side of this apparatus, made by Captain P.S. Hay, showed that it was highly efficient. According to Mr T. C. Maynard manager of Norton colliery, North Staffordshire, a dust collector at a loading point in the Coxhead seam removed half to one lb of dust per ton of output. This dust collector saves the application of half a ton of stone dust per shift which counting the cost of the dust, wages for distribution and retaining means £450 a year
At another colliery the fitting of one dust-extractor to a loading point of a gate conveyor dealing with 400 tons of coal removed 70 lb. of dust, of which 90% passed through a 200-mesh sieve each shift and saved 38% of the cost of dust treatment, or an annual amount of £300.
The capital cost of the dust-extractor was less than £50 but to this must be added running costs. Economically it was a paying proposition, as well as an asset to safety and comfort.
A simple innovation, but one of great importance, is the covering in of gate conveyors. Where one is placed in an intake airway, the velocity of air causes fine dust to be swept off coal, as it travels along the belt and drives it through the face, where it is a nuisance to men.
Much success has been attained by merely stretching brattice cloth over the conveyors at Chanters colliery, Lancashire.
At Whitfield colliery, North Staffordshire, the speed of all belt conveyors has been reduced, to minimise the amount of dust dispersed. It is stated that loaders who formerly wore respirators have been able to discard them since the change.
Foremost amongst agents for dealing with coal dust is water in the form of mist. To be really effective in catching dust particles, water particles must be fully as numerous, but it would be impracticable to supply a water drop for every speck of dust. It would increase humidity too much, would need too much water and would have bad results on the strata. Drops therefore, must be broken into mist and for this purpose compressed air is convenient.
A tub of water, a jet of compressed air and a properly designed sprayer are all the requisites for a mist projector, but a little “perminal” placed in the water adds to the efficacy.
Use of Mist-Projectors
Applications of mist-projectors are numerous. They can be employed in screens to prevent dust being drawn down the pit shaft. They incidentally serve to improve lighting conditions and ensure cleaner coal. A photograph of the Holditch colliery multiple jet projector is shown in the report. The jets were originally intended for acetylene burners. The device is shown fixed to a rotary tippler to blow a dense mist into each tub as it is emptied. It has been found by experience that the tippler is stopped for five seconds after it has made a quarter of a revolution the inside of a tub is penetrate by the mist and most of the dust is trapped. As Mr John Walker, the general manager, says tipplers are rarely occupied all the time and they may as well stand when it does most good as at any other time.
If steam is available it would be better than a water mist and would need nothing more than a fine nozzle. Steam forms the finest mist and wets coal dust easily.
Underground mist-projectors can be and are, used to create a barrier at the entrance to the return airway to entrap dust coming from the face. Two, three or four projectors disposed round the periphery can fill completely an airway and wet all the dust in the air. If the wind velocity is high, however, the wetted dust may not settle before the spray has dried and then dust floats onwards as if it had never been wetted. It seems desirable, therefore, to have expansion chambers, that is, wide spaces where the air velocity will be reduced considerably, near projectors, in which dust can settle. This idea has not been tried, but I suggest it as an experiment.
The total effect of these four measures, namely, a dust trap at the loading point; covering the belt conveyor; enclosure of the transference point; and use of a mist projector; should make a wonderful difference in face conditions; whilst placing mist-projectors at the inbye end of the return airway as well should mean that the dissemination of practically half a ton of coal dust per shift may be prevented. Obviously these measures will pay for them-selves.
Less Dust Production
Hydraulic coal-busters, originally provided as a substitute for explosive in places where shot-firing was prohibited, have the attendant advantage of reducing the amount of dust in facers. Shot-firing in coal produces enormous quantities of dust but coal-busters rend coal down in larger pieces with little dust. The latest application is a compressed-air driven pump to operate the “busters”. It is being tried experimentally at Whitfield colliery, North Staffordshire.
Pneumatic picks, also in substitution for shot-firing have been found useful for reducing dust production. To reduce the huge amount of dust produced by coal-cutting machines it is necessary to prevent cuttings being carried back into the undercut and ground up. It can be done by “gummers” or “jud-cleaners” fixed to machines. These are manufactured by several makers of coal-cutters and have advantages besides that referred to. There is one type that deposits cuttings in a neat heap alongside the conveyor and pushes them out underneath other cuttings in such a manner that there is a minimum exposure to air currents.
For overcutting machines a comparative inexpensive innovation was tried successfully at Victoria colliery, North Staffordshire, where a turret machine was used in the Eight-feet seam. A shroud consisting of sections of conveyor belting was fitted and arranged to scrape the roof and face tightly.
The final device to be described is a water barrage at Astley Green colliery, Lancashire, and Mr Frazer concludes this section with the comment:-
Through precautions taken to combat dust dangers cannot prevent firedamp ignitions, they will limit their disastrous consequences.
Fire-fighting Apparatus
On this subject the Divisional Inspector says:-
There were three ignitions of firedamp in machine undercuts, assumed to have been caused by sparks from machine picks, one which resulted in the loss of a conveyor district and all its haulages, arches, rails and other appliances. All were highly dangerous.
In order to deal with a fire resulting from an ignition of the description,
Mr E Small, Manager of Shelton Deep colliery, North Staffordshire, has designed a water tank, to be superimposed upon a coal cutting machine for the purpose of making a jet of water available at short notice. It holds 16 gallons and is totally enclosed, except for an inlet pipe for compressed air and an outlet pipe for water. There is attached, but coiled in a separate box on top of the machine, 20 feet of hose with a nozzle. When air pressure is turned on to the tank, a jet of water of 27 feet effective radius is forced from the nozzle and plays for about two and a half minutes at 6 gallons a minute. The radius of action is 47 feet from the machine.
Six of these tanks have been constructed and are being fitted. The apparatus does not appear to be cumbrous.
The idea was one that originated from the lessons taught by the Holditch colliery disaster. Another idea was to equip completely all the colliers connected with the Shelton Steel, Iron and Coal Company with high pressure water to all working faces. Some pits are fully equippt and others are well advanced.
North Staffs Safety Officer
North Staffordshire coal-owners appointed a safety officer, Mr T Boydell, nearly two years ago at the time of writing. He has his own staff and in addition three assistants stationed at important colliers. Theirs is a duty of analysing all reports of accidents, investigating personally, when practicable, accidents, both serious and minor and advising as to prevention. Mr Boydell attends to the safety posters and takes a big interest in the training of boys; safety badge classes and such other welfare activities as have a bearing on health and safety.
His assistant at Sneyd colliery has wide powers. He may dismiss a man for breach of safety provisions and has authority over the undermanager in safety matters though he must not concern himself with questions of out-put.
In regard to propaganda, Mr Frazer states:- There is nothing new to report under this heading. A few safety posters are stuck up; a few safety bulletins issued; a few illuminated signs exhibited; but nothing striking or original seems to have been evolved during the year.
I saw one illuminated sign in a man-haulage road underground saying “Safety First” and on inquiring how long it had been there was told “At least three years.” It must have become a commonplace sight to the miners and must long ago have ceased to attract attention or to mean anything; it would have been a simple matter to change the wording week by week.
In regard to protective devices, North Staffordshire, for its relative size, is well ahead, except in regard to shin guards and eye protection.
Holditch Colliery Amenities
When baths under construction are completed there will be baths at 30 mines in Lancashire. 12 in North Staffordshire and 3 in North Wales provided by the Miners’ Welfare Fund and in addition, 2 in Lancashire 2 in North Staffordshire provided by colliery owners.
The erection of such handsome buildings among drab colliery surroundings has awakened the aesthetic sense of some owners and they have made a general clean up. For instance, at Holditch colliery a clean sweep has been made of the old lamp house, deputies report room, first aid room some minor buildings and an untidy scrap heap. A new model lamp house has been constructed with heated glazed passages round it where men can wait in comfort on wet days for lamps, and checks. The other offices have been built to conform to the design of the baths, whilst the space occupied by the old buildings has been levelled, turfed and set out into gardens which greet the miners’ eyes on leaving the gages. The effect of pleasant surroundings on freshly bathed men, with warm drinks from the canteen inside them, is likely to send them home in a happier state of mind than if they were to pack themselves into a workmen’s bus in sweat-sodden, filthy clothes, shunned by everyone wearing clean suits. The moral uplift of pithead baths does not end with the promotion of self-respect and contentment in miners; it goes into their homes as well.
What has been done at Holditch colliery, ought to be done at many other collieries.
Pit Precautions Aug 9th 1939 Evening Sentinel
There is little of conventional or stereotyped about the annual report of
Mr E. H. Frazer. O.B.E. - M. - Sc. Divisional Inspector of Mines for the North Weston Division which comprises Lancashire, and Cheshire, North Staffordshire, and North Wales.
It contains criticism, which is free and frank and definitely constructive. So it is of real value.
The advent of new and more stringent regulations as regarding the treatment of coal dust makes a review of present practice important.
Following the operation of the original regulations which made compulsorily the dilution of coal dust with inert dust (stone dust) there was a steady reduction in the incident of large-scale explosions involving heavy toll of life, until many people began to experience a certain confidence that such disasters were of the unhappy past.
Unfortunately, however, a new type of accident began to develop, often initiated by a fire at thee coal face, sometimes leading to an explosion or explosions, and most regrettable involving serious loss of life. New mining conditions had arisen, resulting from mechanisation, and it could hardly be doubted that the different kind of accident was connected, more or less, with the changed conditions.
Machine mining and mechanical conveying make more dust that the old hand-work. Now mere dilution of coal dust is not enough.
Mr Frazer shows the tremendous amount of inert dust which has to be transported into the mine and distributed on to the roads, in order to effect required dilution. And, sooner or later, the mixed coal and stone dust, must be swept up and sent out of the pit again – a costly business.
Accordingly, and valuable, Mr Frazer details methods of preventing coal dust accumulation and illustrates them with eight photographs and a diagram. Briefly , the newer and very desirable technique consists of trapping the dust at the loading point; covering the belt-conveyor; enclosure of the transferring point; and use of a mist projector. These four methods; says Mr Frazer should make a wonderful difference – and that out-come can readily appreciated. There are also useful references to means of combating coal face fires.
North Staffordshire
Mr Frazer importantly emphasises the fact that falls of ground and haulage accidents attract far less public attention than an occasional serious explosion, but they actually account for 75% of the total casualties.
He is all out for reducing accidents from falls and haulage – as well, of course, as eliminating, if possible, large scale disasters.
The Divisional Inspector comes down heavily on North Staffordshire in regard to casualties from falls of ground and says, “North Staffordshire seems to be going from bad to worse”.
The remedies (he states) are better discipline, effective roof control, better setting of supports, and more frequent examinations, though examination must never be allowed to take the place of support.
Serious attention will certainly be given to Mr Frazer’s uncompromising comments.
Pithead Baths
In this North Staffordshire coalfield we know the boon of pit-head baths and the radical improvement in the social life of the miner which they have affected.
This week the Divisional Inspector of Mines, Mr E H Frazer recorded that baths completed or under construction in North Staffordshire numbered 12 provided by the Miners’ Welfare Fund and 2 provided by the colliery owners.
The Divisional Inspector also reported that the erection of these handsome buildings amidst drab colliery surroundings had awakened the aesthetic sense of some owners, so that have made a general clean-up and affected a pleasant layout of the premises. In particular he quoted Holditch Colliery, where old buildings have given place to turfed spaces and gardens. With Mr Frazer’s commentary there will be felicitous agreement:-
The effect of pleasant surroundings on freshly bathed men, and warm drinks from the canteen inside them; is likely to send them home in a happier state of mind than if they were to duck themselves into a workman’s bus in sweat sodden filthy clothes shunned by everyone wearing clean suits. The moral uplift of pit-head baths does not end with the promotion of self-respect and contentment in miners, it goes into their homes as well.
Now the annual report of the Miner’s Welfare Fund shows that a record advance for a single year in the provision of pit head baths was archived in 1938. The number completed in that year provided for a further 55,600 persons and those under construction for nearly 73,000 more mineworkers
The provision of pithead baths is being speeded up by the welfare levy being reinstated at a penny per ton on output after having stood at a halfpenny for several years.
The baths are generally welcomed by the miners is shown by the fact that with 93% of the workmen used them compared with 83% 7 years ago.
Other Amenities
The work of the Miner’s Welfare Fund goes far beyond the building of pithead baths. In the aggregate over five and a half million pounds have been spent on facilities for indoor and outdoor recreation and cultural activities, three and a half millions on convalescent homes, hospitals, ambulance services, nurses services, and special medical treatment, considerably over a million pounds on safety in mines research.