The Stratified Ironstone, Shale and Fireclay Mines (Explosives) Regulations 1956

3.  No person shall be qualified to be appointed or to be a shot firer unless—

(a) he has attained the age of twenty-one years; and

(b) he has had not less than three years practical experience below ground in one or more mines in which coal, stratified ironstone, shale or fireclay was in the course of being worked, including employment for not less than eighteen months in one or more of the following, namely—

(i) getting or cutting any of those minerals;

(ii) ripping in a roadhead;

(iii) setting or withdrawing supports at or building packs at a face from which any of those minerals was in the course of being worked;

(iv) drilling shot holes at a face from which any of those minerals was in the course of being worked;

(v) for not more than six months, repairing or enlarging roads or driving cross measure drifts;

(vi) in the case of a master sinker or a deputy whose district consists of a shaft in the course of being sunk, sinking operations.