293.540. After a reasonable time has been allowed fordrifting and development operations, the director may requirethat a noncoal mine operating through either a shaft, slope, ordrift, have not less than two adequate and accessible outlets asa condition precedent to employment of any person in the mine.In mines opened after the effective date of this chapter, allvertical shafts shall be located not less than one hundred fiftyfeet apart.
(L. 1959 S.B. 188 ยง 58)