Original vintage mining magazine ad for THE J. GEO. LEYNER ENGINEERING WORKS COMPANY. Main office and factory was located in Littleton, CO.  An Unsolicited Recommendation by A. W. Warwick of the Colorado Chapter of The American Mining Congress for the No. 7 Water Leyner Weighing 120 lbs.  Letter was written by A. W. Warwick when he visited the Roosevelt Tunnel and was impressed with lightness and smallness of the machines they were using.  Old 1910 coal mining industry advertisement.  Would display beautifully matted and framed!