File:Transactions (1871) (14590152999).jpg

Identifier: transactionsmining27amer (find matches)
Title: Transactions
Year: 1871 (1870s)
Authors: American Institute of Mining, Metallurgical, and Petroleum Engineers
Subjects: Mineral industries
Publisher: New York (etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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rom this mine 448,707 tonswere produced in 1896; the greater part of which, however,was not Bessemer ore. The ore occurs in lenses, dipping northabout 70° and varying in thickness from a few feet to over onehundred. The ore itself is extremely hard and strong, whilethe green schist ( soap-rock) walls are soft and weak. Themethod of mining, which may be called longitudinal overhandstoping with filling, has been very thoroughly described byMr. D. II. Bacon,% and I will only supplement his paper. * The Geological Structure of the Western Part of the Vermilion Range,Minn., by Messrs. Smyth and Finlay, Trans., xxv., 595. f The Mesabi Iron Range, by H. V. Winchell, Trans., xxi., 644. X System of Filling at the Mines of the Minnesota Iron Co., Trans., xxi.,299. 346 METHODS OF IRON MINING IN NORTHERN MINNESOTA. Figs. 2 and 3 are underground views from tins mine. Fig.2, taken on top of the fill, shows a chute tapping a raise inthe foot-wall from which rock is obtained for filling. As the J^ZW
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/? •■ p* R. R ^*#*~ yv Scale of Miles X £= 0 10 20 30 40 ,. AMERICAN BANK NOTE CO..N YiG. 1.—Map of the Iron Ranges of Northern Minnesota. back of ore is blasted away and the level of the fill rises, therock-raise is tapped higher up. The side of the raise, at firstformed by the ore, is maintained, after the ore is removed, by METHODS OF IRON MINING IN NORTHERN MINNESOTA. 847 timbers ; or else the rock-raise is replaced by a timber chutecarried up with the fill, either of which arrangements will carrythe rock-raise through the fill to the level below, where it maybe used in mining a lower block of ore. The car used for distributing the fill is also shown. The boxof the car can be swung in a horizontal plane so as to clumpeither to the right or left side of the track as well as over theend, which permits of making a wide fill for each position ofthe track. The diamond-drill, shown in Fig. 2, is used for drilling holesin back-stoping. A Sullivan E drill, run by compressedair, is

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