longer than 21 yr., even though apparently safe and in good condition. Frequent inspection of air shafts must be made to keep them open and free at all times from ice and other obstructions. A fire boss must make this examination and travel either up or down such shaft once each day, the mine foremen once each two weeks, and the superintendent once a month. The company's rules require that in mines generating explosive gas not less than 500 cu. ft. of air per min. per person employed in the mine shall be provided at the intake and this must be so distributed that there will not be less than 300 cu. ft. per min. per person employed in each split at the working faces. No mine shall have at the intake less than 300 cu. ft. of air per min. per person employed, and at the working places at least 150 cu. ft. per min. per person employed. Measurements of air supplied are carefully made and reported to the general office once each week. Local officials at mines generating gas are required to keep air up to the working faces and to such other places where explosive gas might be encountered. At a number of the larger and more recent plants, the ventilating fan is operated by two engines, one on each end, and either of them powerful enough to operate the fan in case of failure of the other. All ventilating systems in the mines are ascensional. The The Clowes hydrogen test lamp is used in all mines generating gas, for testing purposes. Samples of air are taken in gaseous mines and sent in copper cans to the company's laboratory, where they are analyzed. results of the analyses are reported to the general office and to the mine. these show a percentage of explosive gas which might have been detected by the Clowes lamp, the party making the test and reporting no gas is required to make an explanation. Boreholes are frequently drilled from the surface to release any dangerous accumulations of explosive gas in the gob, where these cannot be removed by the mine ventilation. Shot firers have been employed to do all blasting by battery, and inspect all places where shots have been fired to see that there is no fire or other danger thereafter. Only the safest permissible explosives are used, and all tamping is done with clay. All safety-lamp mines are examined on Sundays, holidays and lay-off days, and all mines which have been idle for more than two consecutive days are examined before operations are renewed. In the larger mines, wherever safety lamps are used, auxiliary escapeways are provided. In some instances these are stair shafts from the surface to the mine, placed in the active working sections, and used also for additional ventilation. In other cases, means of escape are provided by having connections between mines, which are closed by double iron doors. Frequent examinations are made to see that these doors are always in condition for use. Where coal dust occurs, a system of pipes and a supply of water under sufficient head and all necessary appliances are provided to dampen thoroughly the floor, sides, and roof of all parts of dry mines. On rope haulage, a device is provided for disengaging the rope from the trip as soon as it is given slack. Brakes are provided for all mine cars and 2 ft. clearance is provided on all haulageways on one side; this side being indicated by a wide whitewashed strip on the rib. Systematic timbering systems are devised and strictly followed. Printed regulations cover the system of timbering in rooms, headings, and in rib and pillar drawing; these are worked out to suit conditions at the various mines. Timbering is not set without caps or cross-bars. All All mines have complete mine-telephone systems. Stables, pump rooms, haulage-engine rooms, shaft bottoms, underground offices and all such places where men might congregate are of fireproof construction and are kept clean and neat. No open lights are allowed in any building. Cans are provided for the reception of oily waste, grease, small quantities of oil, etc. electric wiring is carefully inspected twice each year. All bare power lines underground and on the surface are properly guarded for their entire length by a neat wooden guard, so as to prevent the workman or his tools from coming in contact with the same. For the same reason, trolley wires for cokedrawing machines are placed at a sufficient height to make contact with tools unlikely. A system of checking men in and out of the workings is maintained at all of the mines. All abandoned places in the mines are fenced off. The company employs four mine inspectors, one of them acting as chief. It is the duty of these men to visit each mine and thoroughly inspect it at least once every 60 days. When an accident occurs in or about any mine, the chief mine inspector promptly visits the scene of the accident, gathers all of the data he can relative thereto and makes a sketch of the surroundings. This sketch is put into permanent form, blueprinted and sent to each mine with a circular letter, giving a full account of the accident and making suggestions for the prevention of similar ones. This is discussed at the meeting of the local officials at each plant. Once each week, the superintendent of each plant and his subordinates meet and discuss mine conditions and operations in general and especially matters pertaining to the safety of their employees. The discussions of these meetings are reported to the General Superintendent each week. General meetings are held at stated intervals at the general office, which are attended by the superintendent of each plant and heads of departments. Projections for mine workings are made far in advance of the actual work, and the haulage and ventilating problems are planned so that when the mine is developed the best system is in use. Specifications are written for each mine, stating where and how the mining is to be done. The officials of the company make detailed inspections at intervals, insuring that their instructions and the best methods are actually followed. A safety committee of three or four men is appointed at each mine, which inspects periodically the working places, roadways, ventilation and any other things which in its opinion might be the cause of an accident. The committee reports in writing to the superintendent of the mine, who forwards the same to the general office. These suggestions are immediately acted upon and all dangers reported, should there be any, are removed as quickly as possible. Three rescue and first-aid stations are maintained at the different plants of the company, which are fully equipped with the best apparatus and accessories obtainable. About 400 men have been thoroughly trained and qualified in both rescue and first-aid work, local contests being held by the different teams at various times. Emergency hospitals, fully equipped, have been provided at a number of the largest mines. Tests are made frequently for gas above roof falls in gobs. Work is prohibited in any place in which gas is found, until after it has been removed. Mine inspectors instruct all new employees about the dangers of their work. MINE-RESCUE WORK Mine-rescue work is usually understood to mean the rescue of men or the recovery of bodies after a mine explosion, mine fire or other disaster. In the case of explosions or fires it implies the use of so-called rescue apparatus consisting of oxygen helmets, mouth-breathing apparatus, etc. Organization.-The organization for mine-rescue work will differ so widely with local conditions that but little may be said on the subject in a book of this kind. Careful preparation and training of a rescue crew here means everything. While rescue work may be undertaken by untrained men it is necessarily much slower and more dangerous than where a welltrained, well-disciplined and thoroughly reliable team of helmet men are at hand. As to the selection, organization and training of a helmet crew the U. S. Bureau of Mines has done much valuable work along this line, and every mine or group of mines under one management should avail itself of the instruction, training and advice of the mine-rescue experts on the various mine-rescue cars maintained by the government. At least four helmets and preferably six should be available at all times for immediate use, and the organization of the team should be such that not more than half its members should be underground at any one time, that is, with a rescue team containing 12 men, 6 should at all times be available for instant call to service, and at least 4 of these should be thoroughly familiar with the underground workings. All should be men of good physique, sound heart and of known re liability, nerve and coolness. First Steps after a Disaster. It is extremely important that immediately upon the occurrence of a mine disaster, such as an explosion, that the proper steps toward rescue be taken promptly. Here again much will depend upon circumstances and local conditions, but in a general sense the following is necessary. Call the helmet men together, summon aid from nearby mines, summon the nearest government mine-rescue car. It is important that exploration work start as promptly as possible. Consequently the helmet men should precede all others into the mine. There are two other important considerations which require careful attention; the ventilation must be restored as quickly as possible and the means of communicating with the underground workings must be kept intact or repaired immediately. If the mine is a shaft operation the hoisting cages if damaged should be repaired as quickly as possible or if this is out of the question a temporary means of raising and lowering men and material must be had. For this purpose some mines keep on hand an emergency cage so that if the regular cages are put out of commission, men at least may still be raised and lowered by the emergency apparatus. Reversing the Air Current.-An explosion usually causes more or less havoc with the underground ventilating system, that is, brattices are frequently destroyed, stoppings broken down, etc. There is a wide diversity of opinion among engineers and mine men in general concerning the advisability of reversing the air current, that is, changing a blowing fan to an exhauster and vice versa after a mine disaster. This is a question, the expediency of which had better be thought out before the explosion occurs, or in any instance the current should not be reversed without due and careful consideration. Men attempting to find their way out of the mine after a disaster are apt to be guided largely by the air current flowing. They are in utter darkness unless of course they be provided with safety lamps or electric lamps and will naturally move against the air current. If this current is reversed it will in many instances drive the foul and poisonous gases resulting from the explosion directly upon them. There may however be instances wherein it would be advisable to reverse the current. The Work of Recovery.-Mine-rescue and recovery work requires above all else a strong and careful leader. This leader should if possible be known at least by reputation to all the men engaged in the work. He should be a man whom all can respect and trust. After it has been ascertained that the fan is in working order and at work (an auxiliary fan may be used if necessary), and a means of access to the mine is established, the helmet men with their mice, canaries or other means of testing the gas may enter the mine. These men are to the main body of the rescuers what the scouts are to an army-inlarge measure at least they constitute the department of security and information. Their work will be to explore the mine, ascertain the presence of dangerous gas and bring to a point of safety any living men that may be found. Unhelmeted men should follow them, restoring the ventilation as they go. This usually requires the building of a considerable amount of temporary bratticework and stoppings and material therefor (boards, plank, posts, canvass, nails, spikes, etc.) must be provided. No one should be allowed to enter the mine merely through curiosity. Whoever enters should be immediately put to work. The person directing recovery work may do so either from the surface, the foot of the shaft or some other convenient point, communicating with his various lieutenants either by word of mouth, by telephone if possible or in some instances by messenger at frequent intervals. The person directing rescue and recovery work should be careful in his selection of lieutenants. The ventilation apparatus is perhaps the most important of all machinery. It must be kept going, or if a shutdown is absolutely necessary, this must be anticipated, a sufficient amount of time to allow all men, helmeted as well as unhelmeted to be withdrawn, from the mine before the air current is actually stopped. It is well therefore to place an experienced man at the fan, whose sole duty it shall be to keep it in operation. If necessary, this man should have all the helpers he may require. The hoisting apparatus is also important, but if possible the regular hoist man should stick to his post. There should be appointed a gang whose duty should be to secure and bring to the mouth of the mine the materials necessary for bratticing. If the mine is electrically lighted a competent electrician with a requisite number of helpers should be put to work repairing or establishing lighting conditions. The brattice men following the helmet crew should be under an experienced brattice builder who is competent to see that the work is done properly and rapidly; in many instances also a man with such assistance as he may need may be employed to transport the various materials from the mine entrance to the point where they are needed. Furthermore, since mine rescue work usually lasts for several hours or even days a commissary department should be established so that food such as sandwiches, hot soup and particularly hot coffee may be served to the men at work at regular intervals and the coffee whenever they desire it. skilled in first aid as well as physicians should also be on hand to give prompt and efficient treatment to any men that may be found alive. The helmet men will of course remove few if any dead bodies so long as there is even hope of finding living people in the mine. Once a man is found alive he should be promptly taken to a point where at least reasonably pure air is available. Men In selecting his lieutenants heading the various gangs or groups of men above mentioned, the man in charge should use careful discretion and delegate to each subordinate the work with which that particular man is most familiar. Thus a mine official of even high standing such as a superintendent might be given a job of caging at the ground landing if he were known to have had successful previous experience at that kind of work. The man in charge of the transporting of material from the shaft bottom to the point of use might be a mine superintendent or he might be a motor boss, depending on his previous experience in the transportation department. The main idea is that every man in charge of a gang should know the work which he is called upon to do, know it well and be a person that can be depended upon. The success of mine-rescue work, that is, the recovery of living men, will often depend much upon the coolness, good judgment and persistence of the man or men in charge of this work. The careful mine official will therefore think out and decide many possible mine-rescue problems before the actual time of disaster arrives. MINE-RESCUE APPARATUS Mine-rescue apparatus, so-called, is of two general types: (a) breathing apparatus, used by the rescue crew, and (b) resuscitation apparatus used by or rather on the people recovered. Breathing Apparatus.-There are two types of breathing apparatus in general use in the United States. These are known respectively as helmet apparatus and mouth-breathing apparatus. The helmet apparatus consists of a metal helmet which may be strapped over the face and be rendered airtight by an inflatable gasket which fits under the chin and extends upwards completely encircling the front portion of the head or by other means. The rear portion of the head is protected by a leather apron. The mouthbreathing apparatus is exactly similar except that in place of the helmet a mouthpiece which is provided with a device to close the nostrils of the nose is strapped onto the head. The oxygen containers, pipes, breathing bag and regenerator are at least similar if not identical in the two types and sometimes are made interchangeable. The operation of the instrument is simple and may be readily understood from the diagrammatic drawing Fig. 1. The oxygen tanks AA are connected together and the flow of oxygen is regulated by the valve B. Opening this valve allows the compressed oxygen in the tanks to flow to the pressure gauge C and to the reducing valve D, which is fitted with a safety valve E. The oxygen is reduced to a predetermined pressure in the regulating valve and next passes to the injector F. It then flows through the pipe to the inhalation compartment of breathing bag H and from thence to the mouthpiece or helmet. After being exhaled from the lungs the gas passes to a second compartment or exhalation bag I which is part and parcel of the inhalation bag but separated therefrom by a partition. From here it passes through the pipe J to the regenerator. This is provided with potash in a granular form which is arranged in wire gauze trays around which the exhaled oxygen passes and from which the carbon dioxide is absorbed by the chemical. It then passes through the pipe K to the injector where it is reoxygenated and again passed to the breathing bag H to be inhaled. Under ordinary conditions the oxygen tanks contain sufficient compressed oxygen for 2 hr. of hard work. A smaller regenerator is sometimes employed for practice work in the smoke room, thus reducing the cost of each practice. When the mouth-breathing apparatus is used, it is advisable to supply the wearer with smoke goggles to protect the eyes in case work is being done in any gas which would tend to irritate them. The operation of the helmet is practically the same as that of the mouthbreathing apparatus above described except that the helmet is substituted in place of the mouthpiece. The mouth-breathing apparatus is somewhat lighter and simpler both in construction and operation than is the helmet. The helmet, however, possesses the advantage of allowing the wearer to talk with his companions which is difficult, if not impossible, with the mouth-breathing apparatus. Oxygen for use with mine-rescue apparatus may be purchased in large cylinders from whence it may be transferred to the small cartridges of the breathing apparatus by means of a suitable hand pump. Such pumps are usually made double-acting and will compress the oxygen in the small tanks to approximately 120 atmospheres. S 122 A P Self Rescuer. A small type of breathing apparatus for use in noxious or poisonous gases and holding a charge of oxygen sufficient for 30 min. work is known as the self rescuer. This apparatus is compact, weighs about 612 lb., can be quickly adjusted to the U wearer and does not require previous training. This apparatus is shown diagramatically in Fig. 2. Here S represents the oxygen cylinder, U the closing valve, P the potash or regenerating cartridge, A the breathing bag, L the respiration pipe which is provided with the rubber mouthpiece M. The apparatus is suspended by a strap around the neck while a canvas apron fastened around the waist holds the apparatus in place. The exhaled air flows through the respiration pipe L into the regenerator P where it is subjected to the action of the carbon-dioxide-absorbing chemicals. Freed from the products of respiration the air enters the breathing bag A where a fresh oxygen supply is provided from the cylinder S. The regenerated air is again drawn through the potash cartridge where it is once more subjected to purification and is inhaled through the pipe L. Care must be taken with any of these instruments to provide fresh potash cartridges for regenerating the air. Fresh cartridges when shaken will rattle, spent ones will not. FIG. 2 Resuscitation Apparatus.—In cases of partial asphyxiation from poisonous gas or drowning, severe electric shock, etc., a means of compelling the patient to breathe is necessary. This may be supplied either by artificial respiration according to the Schaefer or Sylvester method or by some variety of resuscitation apparatus. One of the simplest of resuscitation apparatuses is shown in Fig. 3 and is known as the lungmotor. This may be arranged to administer either atmospheric air only or atmospheric air enriched with oxygen either from a charged tank or an oxygen generator, or pure oxygen from the same source. The lungmotor consists of two-air pumps which are operated simultaneously but which are connected together only by the two flexible tubes leading to the face mask. After the face mask has been adjusted and strapped in place and the adjustment for the size of the patient made by turning the pin A so as to give the proper length of stroke to the two pumps the handle of the machine is simply worked up and down at the normal rapidity of breathing; the operator may judge this from his own respiration. Air is thus gently but positively forced into and withdrawn from the patient's lungs, the lungs meanwhile being maintained at their normal inflation. In |