Coal mining in Illinois . Fig. 61. Circular hoisting shaft Gunite sets in 2% to 3 hours. The cost of application variesfrom 16 to 24 cents per square foot depending largely uponthe amount of water the shaft makes. With a dry andsmooth timber lining the work should average about 20 centsper square foot. The shafts of all mines in Illinois are of moderate size,the largest at the mines examined being 11 by 22 feet. Noserious difficulties have been encountered in sinking flow has never been large. At one mine in District VIa considerable body of quicksand necessitated a reduction ofshaf
Coal mining in Illinois . Fig. 61. Circular hoisting shaft Gunite sets in 2% to 3 hours. The cost of application variesfrom 16 to 24 cents per square foot depending largely uponthe amount of water the shaft makes. With a dry andsmooth timber lining the work should average about 20 centsper square foot. The shafts of all mines in Illinois are of moderate size,the largest at the mines examined being 11 by 22 feet. Noserious difficulties have been encountered in sinking flow has never been large. At one mine in District VIa considerable body of quicksand necessitated a reduction ofshaft size but in general shaft sinking is comparatively cheapand Coping
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectcoalmin, bookyear1915
