Show HAZARDS IN connection WITH concentrated COAL MINING discussion OF USES AND ABUSES OF MODERN mechanical METHODS by D harrington records indicate that to date fewer than of our approximately coal mines less than 3 per cent are using the newer or concentrated mechanical mining systems and of these operations it is improbable that as many as fifty produce full tonnage from the newer systems in many mines listed as using the newer or concentrated methods more than seventy five per cent of the output comes from the older parts of the mine where the old methods are employed in 1925 the total coal tonnage from the newer methods for the united states is given as a trifle over or a little over 1 per cent of the tonnage of the united states and it is probable that 1927 tonnage from these methods was under hence it is is seen that the concentrated mechanical methods are in their infancy and it seems that this should be an opportune time to point out some of the pitfalls to safety that are likely to be encountered with the idea of helping helpin to prevent accidents or disasters and not in any degree with intent to prevent the spread of the mechanization of mines or concentration of mine workers or mine workings in the introduction of concentrated systems of mining largely dependent upon the assumption of much of the burden of underground work by mechanical contrivances with consequent concentration of work and of the working force in m general but little attention has been paid the element of safety discussions of mechanical drilling cutting loading conveying hauling etc have ordinarily been characterized by an assumption which is inferred rather than uttered that safety will be enhanced rather than in any manner retarded or lessened by concentrated mining methods and devices there have been a few attempts to show that mechanical mining is safer than are the more primitive ways of doing underground work by man power a few figures or brief statistical records have been advanced tending to indicate that the concentrated systems using mechanical devices have actually shown fewer accidents per tons of coal produced than has been the case in the same mines or mining regions when the older hand methods were utilized chief engineer safety division U S bureau of mines there have veen b ean however a number of places where the concentrated systems have had bad to be abandoned chiefly on account of the safety element and there is much probability that some of these systems which in themselves are or can be made to be reasonably safe will fall into disrepute because of failure of those in charge e to use reasonable care to keep the work and workers safe in fact one state inspection force has already put a ban on the use of a certain type of scraper system another has openly voiced opposition to long faces and a third has barred methods or systems that require the driving of single entries while there are plenty of good and sufficient reasons why the newer or concentrated cent rated systems using mechanical rather than man power can will and should be used in our mines there is absolutely no justification for attempting to utilize these newer ideas without the taking of common sense precautions looking to the safety of the mine and of the miners as well as to lower costs and to increase tonnage generally it is futile to discuss dangers unless there can be given some specific cases of occurrence of accidents unfortunately notwithstanding the newness of this type of work there is no dearth of such instances in connection with mechanical mining or with so called concentrated systems A recent explosion in wales has been blamed upon methane ignition by a conveyor and while the proof is not as definite as one would like on the other hand the methane accumulation in this mine is very likely to have been caused by the lax methods of ventilation that only too 1 generally accompany the newer mechanical systems the explosion was not very violent or widespread but it killed fifty one men because of their being concentrated around the conveyor work inherent dangers and the human equation in a pitching seam in the western part of the united states methane was ignited from an open electric motor on a face conveyor and eleven workers were killed this affair also illustrates one of the inherent dangers of concentrated cent rated systems since pince this gas ignition extended only a few hundred feet and produced practically no violence and the eleven men were killed because of their being concen grated within approximately a foot length of conveyor and it is probable that the flame from this ignition would have caught only the usual one or two workers if it had occurred in the ordinary room of the older method of work here again was the sluggish ventilation which accompanies the new or concentrated systems so often that it seems inherent to them in a southern mine nine workers along a scraper face were killed on an off shift while timbering undercutting etc to prepare for the oncoming shift and in this instance the gas was probably ignited by an open light again there was merely a local inflammation with little or no violence and again lax ventilation methods were used the large death list was moreover due to concentration of workers in a small area and under the room and pillar system only the usual one or two room workers would probably have been caught in a western mine of fairly large capacity which had a record of no fatalities over a comparatively long period a conveyor system was installed in one place and within a year there had been three fatalities one at a time in the one working place served by the conveyor here the trouble seemed to be largely a matter of too much noise by the conveyor the workers being unable to hear the usual slight warning noises preceding the falling of rib or roof material when the older method of work was utilized the occurrence of accidents when excessive noise at working faces drowns the noise of props or roof failing is difficult to avoid face machinery should be kept well oiled and in good repair and should be stopped at intervals to allow surrounding conditions to be ascertained water used to wet the coal tends to reduce the noise from conveyors scrapers loaders etc in another mine in which a scraper system was handling the coal from a long face of about feet coal had been removed from a comparatively large area and the overlying material was held by props when a mass of overlying sandstone about feet in length and 20 or more feet in width with a thickness of ten or more feet fell without warning and caught two men it developed that the mine foreman had examined the place less than one half hour previous to the fall and found it apparently safe there being no evidence of undue weight on the props nor could the impending fall be detected by the usual roof sounding methods in this case undoubtedly too much reliance was placed upon the comparatively solid roof and upon props to hold the roof props are far too often relied upon to hold safe the places where there is concentration of numerous workers and in general it would be decidedly safer and in the long run cheaper and more efficient if cribs rather than props were used where numerous workers are assembled in long face work whether with conveyors scrapers loaders or otherwise ventilation makeshifts make shifts and careless carelessness n ess one of the most alarming features about the newer systems of mining is the laxity in connection with ventilation the abovementioned above mentioned explosions at long faces being examples and one one of the worst forms of the tendency to resort to ventilation marke shifts in the newer type of work is the use of blower fans and tubing in supposedly venti lating coalmine coal mine faces there have been numerous disasters due to the use of these fans in coal mines and recently four men were killed in consequence of methane ignition where an entry driving machine working face was forced to rely upon a blower fan and tubing for ventilation there was the usual daily methane accumulation which must be expected upon coming on shift in the morning after the blower has been shut down since the previous shift the night before and the methane in this instance was ignited either by electricity or by open lights carelessness in the use of electricity in connection with scrapers conveyors loaders fans etc is the rule rather than the exception comparatively recently four men one after another were killed while trying to move an electrically driven blower in a mine and in another instance a worker was killed upon coming in contact with an open knife switch controlling electric current to a small blower fan these electrical accidents are by no means infrequent they are likely to become increasingly numerous and their elimination is one of the real problems in connection with the newer mining systems probably the most dangerous features as concerns safety when these concentrated methods are used comes from the fact that it frequently if not generally is considered necessary to complete a full cycle of operations daily if the methods are to be successful and to complete this cycle of operations each day mining men appear to be willing to cast aside one precautionary practice after another long determined as necessary to keep mines sate safe in in fact it is frequently found that practices are used in the mechanized sections of a mine which would not be counte danced in the other parts of the same mine mine which are using older systems of working following are some of the hazards noticed where the newer systems are being used newer system hazards enumerated L 1 in a conveyor or electric loader system operation one usually finds open arcing types of electric motors switches etc at or very close to faces which give off or are at any time likely to give off methane wires poorly insulated or bare are poorly placed and poorly supported and only too frequently the wires lie on the floor and workers are expected to watch their step when walking around 2 much dust is thrown into the air in connection with conveyor or loader work the very fine hence most dangerous dust settling on adjacent surfaces especially ln in the open region from which the coal has been removed therefore in case of a fall of roof in that open region there are likely to be forced over the open arcing electrical equipment not only clouds of fine dust but also methane 3 frequently blasting is done during the working vor king shift and it is not at all uncommon to see fifty or more pounds of explosive with twenty five or more detonators on the floor within a few feet of electric wires or motors or the open lights of workers nor is it uncommon to see nun num blasting holes loaded ready to blast with workers using open lights and electrical equipment in operation close by 4 when shots are fired during the working shift the workers are withdrawn only a short distance hence in case of a blown out shot or gas ignition from blasting the workers are likely in fact are almost certain to be killed or at least seriously injured in blasting during the shift usually permissible explosives are employed but only too frequently this good feature is partly nullified by using fuse instead of electric blasting or by shooting several holes at a time electrically a poor practice especially where men are in the mine in some instances black blasting powder is used in this blasting 6 during the shift and this is little less than criminal especially where the black blasting powder is tamped camped with coal dust and detonated by fuse or squibs squibb 5 in the hurry to complete the cycle of operations upon returning after a blast a minimum of attention is given inspection of the face region for methane bethan e or examination of roof conditions and timbering is done before resumption of work only when absolutely necessary 6 under some roof conditions an appreciable length of time elapses after blasting before the roof will actually fall in pillar or long iong face work and where there is an sturge urge to complete the cycle of operations little or no time is spared to await action of the roof hence there are likely to be and in fact there have been accidents from falls of roof from this cause much if not all of this hazard is escaped in ordinary room and pillar work where shooting is or should be done after the working shift or at the end of the shift 7 generally reliance is placed upon props frequently with very few props in position to hold the roof even with an extensive worked out area or to determine the line of break in the roof in most cases props are entirely inadequate for this service and in the long run are more expensive than would be an adequate system of cribs 8 scrapers mechanical loaders and to a smaller extent conveyors tear out props or cribs and only too frequently operations are kept going irrespective of dangers caused by the removal of the roof supports leaving the props or cribs to be replaced or not as may be determined later on by the boss or the 9 there is generally very little clearance or adequate guarding of moving or electrically charged parts around mechanical equipment near face regions and workers have a minimum opportunity to travel without being injured 10 mechanical equipment such as electrical drills mining machines loaders conveyors and scrapers is noisy hence while in operation at or near face regions the noise from om the equipment prevents the workers from hearing the mor bior or less slight warning sounds generally given before a roof or rib falls this is decidedly serious inasmuch as ag the newer systems with their concentrated more or less continuous attack keep the roof and rib almost continually moving loving and the worker is practically deprived of his main wari warning ting of danger dang er because of the die noise of the machinery concerning single entry practice 11 the advocates of nearly every so called concentrated system give reason after reason why it is essential that single entries of various lengths are necessary and each advocates reason after reason why single entries of to 1000 or more feet ahre are safe notwithstanding that it has been one of the axioms of safe and sane coal mining that under no circumstances should any singe underground opening be driven to tl a length of more than feet it is true that in many instances in the past single entries longer longed than feet have been driven but it is equally true that many disasters have resulted from this and it is also true that several such disasters have occurred in recent years moreover the driving of single entries is not necessary y to the success of practically any methods new or old notwithstanding voluminous arguments to the contrary 12 one of the worst marke shifts to which resort is had in this single entry driving is the use or rather the flagrant misuse of blower fans and tubing for ventilation notwithstanding the fact that these units are operated only during the working shift hence methane is almost certain to accumulate at the face during eight to sixteen hours per day moreover these units are almost invariably poorly installed especially as to electrical wiring and fireproofing and many fires and electrocutions as well as explosions have occurred and undoubtedly will occur from these 13 under stress of completing the cycles of operations in the concentrated systems there frequently is no hesitancy to allow in some instances practically to force workers to work around or under missed shots or to work in close proximity to missed shots while these are being removed or otherwise handled 14 when rock or extra large pieces of coal are brought down by blasting or happen to fall in such manner as to impede the operation of conveyors loaders scrapers etc there is little or no hesitancy in many mines to use the quick lazy and decidedly dangerous adobe or sandblast sand |