(225 ILCS 705/20.37) (from Ch. 96 1/2, par. 2037)

Sec. 20.37. Not more than one shot shall be lighted at the same time in any working place unless the firing is done by electricity or by fuses of such length that the interval between the explosions of any two shots shall be not less than one minute, and in no case shall any shot or shots be fired or lighted which are termed depending or dependent shots, until after the expiration of 10 minutes from the successful firing of the relieving shot or shots. When successive shots are to be fired in any working place in which the roof is broken or faulty, the smoke shall be allowed to clear away and the roof examined and made secure between shots.

(Source: Laws 1953, p. 701.)