225 ILCS 710/46.05

The operator of every mine where motor generator sets or transformers are installed underground shall designate or cause to be designated on the map provided for in the Mining Law, showing the location of transformer stations, at each of the above said stations a sufficient amount of sand, not less than one (1) cubic yard, shall be kept in a suitable place convenient to said motor generator stations and transformer stations for the purpose of extinguishing any fire starting from short circuiting or otherwise. In addition thereto two suitable chemical fire extinguishers shall be kept in a convenient place.