Mining Museums And Tours It then leads into the mine for a 1,300 ft (four hundred m) stroll on level ground via the underground mine. The walk goes via a new 240 feet (seventy three m) section called the Rainbow tunnel which they blasted in 1990 utilizing forty nine http://damien0r9o5.review-blogger.com/26290368/geologic-characterization-of-the-jujo-tecominoacan-fields