Falls of ground which result in large cavities such as occurred in this case can and should be prevented by well known methods of strata control and support. Small falls of ground show the need for more intensive support which is usually necessary also to prevent the falls from spreading. The top and sides of cavities left by such falls should be supported and packed and until this has been completed they should be ventilated to prevent accumulations of firedamp.

Any large cavities in the roof should never be concealed by supports and cover boards, which act as an umbrella and are unable to prevent danger from further falls and from accumulations of firedamp.

A minimum of 20 feet of packing should be stipulated between a road used for ventilation or transport and any waste exceeding 100 feet in width.

Electrical apparatus and cables should be effectively protected against damage such as might cause incendive open sparking, or, where this is impracticable, the electrical apparatus or cables should be moved to a safe place.

The possibility of eliminating incendive sparking, by reducing the time of action of automatic devices for cutting off electricity in the event of excessive earth leakage or short circuit, should be investigated.

Section 55 (1) (a) of the Mines and Quarries Act, 1956, requires the manager of every mine to take such steps as are necessary for securing that there is constantly produced in all parts of the mine below ground ventilation adequate for the following purpose:—-

Diluting gases that are inflammable or noxious so as to render them harmless and removing them.

In this connection minimum ventilation standards on the lines suggested in National Coal Board Bulletin No. 55/153 entitled "Planning the Ventilation of new and reorganised Collieries" should be applied to all mines and efforts should be made without delay to bring those below the standards at least up to the minimum suggested.

Where two intake roads are provided to any coal face without a return airway between them, they should not be more than 30 yards apart to avoid unreliable ventilation of that part of the face between them.