Temporary stoppings near mine openings or other places where they will be subjected to considerable air pressure should be constructed of two to four plies of brattice cloth, depending on the size of the stopping and the distance air must be carried. Temporary stoppings should be set far enough (at least 4 to 6 feet) inside of crosscuts or other openings to leave space for the later construction of stronger and tighter stoppings.

As soon as possible, semipermanent stoppings of boards or stronger material, or permanent stoppings of brick, cement blocks, tile, etc., should be erected to replace temporary stoppings, particularly where the temporary stoppings are under considerable air pressure.

Details of the construction of temporary and permanent stoppings are described in the section on sealing mine fires.

As recovery work progresses, a large number of temporary stoppings may be in use; and to insure that these are kept tight and in good condition, men should be appointed on each shift to patrol and keep the temporary stoppings as nearly airtight as possible.

CONTROL OF VENTILATION

The procedure of alternately exploring ahead of fresh air and advancing the air by erecting temporary stoppings should be continued until the entire region affected by the explosion has been recovered.

In ventilating any portion of a mine after an explosion, the afterdamp should be conducted to the outside by the most direct route. Permitting the poisonous gases to travel through other sections of a mine may seriously endanger the lives of survivors of the explosion or persons engaged in the rescue or recovery work.

Safe practice requires that currents of air be conducted so the ventilation will always be under the control of the man in charge of the shift and the paths the air is traveling will always be known definitely; it is extremely dangerous after an explosion, especially in a gassy mine, to permit air to travel over or through unexplored portions of the mine. Unless this vital precaution is taken, an explosive mixture of gas may be brought in contact with a fire, thereby causing another explosion, possibly with disastrous effects; this has occurred in several cases.

All sections, entries, rooms, and other open accessible workings, etc., if possible should be cleared of afterdamp as work advances; if this is not done, fires may be bratticed off and reach a serious stage before discovery; or explosive, asphyxiating, or poisonous gases may seep from bratticed-off areas, enter the ventilating current outby the point where recovery work is in progress, and seriously affect members of the rescue or recovery crews or possibly cause an explosion. Line brattice will be required for ventilating faces of entries and rooms or when it is necessary to split the air current in entries. If a brattice is required for a considerable distance, it should be erected by setting posts about 8 to 12 feet apart in the center or on one side of the passageway; a board should be nailed along the top of the posts and the top of the brattice cloth nailed to it; probably the bottom end of the brattice cloth also should be nailed to a board or it can be held in place by lumps of coal, pieces of slate, etc.

When a short-line brattice is required to clean out the face of a working place, as from the last crosscut to the face of the place,

sometimes especially in low workings or workings of medium height, it can be erected, quickly by having a number of men hold the brattice cloth in place instead of fastening it on posts. A roll of brattice cloth long enough to reach the desired distance should be held upright in the passageway where the outby end of the line brattice is to start; several feet of the cloth should then be unrolled and held by one of the men, while others advance toward the face unrolling the cloth and holding the unrolled portion to the roof as the roll is advanced, until the ventilating current reaches and clears the face of afterdamp. After the face has been ventilated the cloth can be dropped, rolled up, and used again. Where it can be used, this method is preferable to setting posts and nailing the brattice cloth, as it is much quicker.

EXAMINING FOR AND EXTINGUISHING FIRES

Frequently smoldering fires (which may be dormant for as long as several days and fanned to life by the entrance of fresh air), and sometimes active fires are found after mine explosions. Doors, timbers, gob, dust, brattice cloth, and coal are likely to be set on fire by the heat and flame of the explosion. Such fires are extremely dangerous in gassy mines, as they may ignite an explosive mixture of gas. When exploring ahead of fresh air, rescue crews should make careful examination for fires; and as ventilation is advanced, frequent inspections should be made of the return-air currents for smoke or heated air.

If fires are found while rescue crews are exploring ahead of fresh air, they should be extinguished if possible with water, rock dust, or fire extinguishers before the fresh air is advanced to the fire. When the fire is of such proportions or is so inaccessible that it cannot be extinguished, it should be sealed promptly and effectively.

If smoke and an explosive mixture of gas are encountered and the location of the fire is unknown, it is advisable to seal the region containing the fire, or the entire mine, at once. When the latter is done, to continue recovery operations it may be necesary to use air locks to work around the fire area, as was done following an explosion in Federal No. 3 mine of the New England Fuel & Transportation Co., Everettville, W. Va., in May 1927.

In this instance, smoke and an explosive mixture of gas were encountered shortly after recovery work was started, and the safety of the men engaged in the work demanded that the entire mine be sealed until further plans could be made. It was decided to continue recovery operations by air-locking around the area containing the fire. Figure 25 shows a section of this mine and gives a comprehensive idea of how the work was conducted. Undoubtedly, it was the largest airlocking job ever attempted in a bituminous-coal mine; approximately 35 oxygen-breathing-apparatus crews, working in 6-hour shifts, were employed for a week, and 14 air locks and about 50 stoppings were required to work around the region containing the fire. Details regarding the construction of air locks and procedure to follow have been explained previously in the discussion on the recovery of bodies and unsealing the fire following an explosion in the Horning mine; and the procedure for sealing a fire is described in the section dealing with that subject.

FIGURE 25.-Section of the Federal No. 3 mine in which air locks were used.

RESCUE AND REMOVAL OF LIVE MEN

Sometimes live men are found after an explosion. Usually they are suffering from poisonous or asphyxiating gases, burns, or injuries. Men found affected or overcome in an atmosphere containing afterdamp should have an oxygen breathing apparatus (preferably a halfhour type) placed on them and should be carried to fresh air as soon as possible. If sufficient oxygen is present to support life (a lighted flame safety lamp will indicate this), a gas mask or self-rescuer probably can be used safely instead of an oxygen breathing apparatus.

As soon as possible after live men are brought to fresh air, they should be given oxygen to breathe. The oxygen should be administered (preferably by means of an inhaler) for at least 30 minutes to remove carbon monoxide from the victim's blood. If rescued men are breathing slowly, or not at all, but show indications of life, artificial respiration should be administered in conjunction with oxygen until they are revived or until it is known definitely that it will be impossible to revive them.

Occasionally, live men are found behind barricades erected to protect themselves from afterdamp. Great care should be exercised, if the region immediately outside the barricade is in an irrespirable atmosphere, to prevent poisonous or noxious gases from entering the

barricade while men are being rescued. If fresh air can be advanced to the barricade in a short time, this is desirable and should be done before the barricade is opened. If it is impossible to conduct fresh air to the barricade in a reasonably short time, provision should be made to admit the least possible amount of irrespirable air behind the barricade when it is opened by erecting a tight canvas stopping, with a small opening covered with canvas, a short distance (about 10 to 15 feet) outby the barricade to allow sufficient room to set a stretcher lengthwise between the stopping and barricade.

After the stopping has been erected, an opening large enough to admit an open stretcher should be made in the barricade and covered immediately with canvas. After these arrangements have been completed, the following procedure should be used in rescuing men from behind the barricade.

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If all or some of the men found behind a barricade can walk, they should be provided with the necessary protective equipment, such as an oxygen breathing apparatus (preferably half-hour type), or, flame safety lamp will burn outside the barricade, a gas mask or selfrescuer, and led or assisted to fresh air. If they are unable to walk, four men with a stretcher should pass through the stopping, admitting as little air as possible, and enter the space between the stopping and barricade. They should then pass through the barricade, again admitting the least possible amount of air, and enter the space behind the barricade. A man (depending on the condition of the men behind the barricade) should be selected for rescue, provided with the necessary protective equipment, loaded on a stretcher, taken through the opening in the barricade (the opening then being tightly closed), then through the stopping (this opening then being tightly closed), and finally carried to fresh air by the shortest and quickest route. These operations should be repeated until all of the men behind the barricade have been rescued. Every effort should be made to prevent the admission of irrespirable air through either the stopping or barricade while men are entering or leaving. If reasonable care is exercised, several men can be rescued from behind a barricade with the admission of only a small amount of the harmful air into the barricaded space.

All rescued men, whether from behind barricades or otherwise, on reaching fresh air should be given first-aid treatment, consisting of artificial respiration, if required, administration of oxygen, treatment for shock, and dressing of wounds, burns, or other injuries. Rescued men should be well covered and wrapped with blankets or quilts before being taken outside, and those unable to walk should be placed on stretchers and carried or hauled to the outside. All rescued men should be taken to an emergency or permanent hospital for further observation and treatment.

HANDLING BODIES

After an explosion, dead bodies may be found in various parts of the mine. Some bodies may have no injuries or mutilations, while others may be badly damaged, dismembered, or decomposed.

All bodies should be wrapped in brattice cloth or canvas by the recovery crews and transported to the morgue. When bodies are not recovered for several days they should be sprayed well with a

disinfectant, such as a strong solution of creolin or lysol, before being touched, handled, or wrapped. A tag bearing the serial number and the location where the body was found should be attached to each body. If the location has not been marked previously on the roof or rib, this should be done by the recovery crew. The location, position of the body, and check number or name also should be marked on the mine map. Nothing should be removed from a body while it is in the mine, except in the presence of witnesses, and then only if a written record is made of the material removed. Any material removed from a body should be given to a responsible person to be turned over to the man in charge of the morgue or to relatives of the victim. Bodies received at the morgue should have a morgue number assigned and should be identified if possible.

The official in charge of the morgue should make a record of tags attached by the recovery crews and the check number, if checks are found on the body, and a record of clothing, shoes or boots, money, watch, or other jewelry found on the body; a description of the features, color of hair and eyes, height, weight, and teeth, old scars or fractures, and probable age of the victim.

All clothing and other articles removed from a body should be wrapped in cloth or canvas, tied securely with a tag inside and the morgue number outside, and delivered to the coroner or the relatives of the deceased.

SETTING TIMBERS

Many timbers may be knocked out by the force of the explosion and the roof may be weakened by the heat. As a protection to rescue and recovery crews and others who are required to travel roadways, manways, and entries, timber crews should remove dangerous roof and set necessary timbers as soon as possible.

CLEARING ROADWAYS

Roadways should be cleared of falls and debris and necessary repairs made to the haulage tracks as soon as possible after an explosion. The transportation of material and bodies and the recovery work in general will be facilitated greatly if the haulage tracks and haulage equipment are made available for use. Storage-battery locomotives (permissible type), horses, or mules should be provided for motive power. Trolley-pole or cable-reel locomotives should not be used because of the hazards of igniting explosive gas.

PREPARATION FOR RESUMING OPERATIONS

After the area affected by a mine explosion has been explored, the bodies removed, fires (if any) extinguished or sealed, and the inspectors and mine officials have completed their investigations, crews should be set to work building permanent stoppings, cleaning haulage roads and air courses, and making such other repairs as may be necessary to safe operation of the mine.

When all necessary repairs and changes have been made, the State mine inspector should examine the mine before regular work is started; if, in his judgment, the mine is in safe condition, operations may be resumed.