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Mining
Title: Description of the Two Mining Processes
Transcription: Two general types of mining are practiced on the Mesabi—underground and open pit. If the ore body lies near the surface, it is cheaper to strip away the top soil and remove the ore with steam shovels which load directly into railroad cars. This, of course, is the latter or open-pit method, and operations are confined largely to the season of navigation, When Lake Superior is free of ice. when the ore mined may be sent directly to the ore docks Places where ore is loaded onto ships. and shipped East. Open pits which work throughout the winter months are forced to stockpile Accumulate. their ore; that is, to heap it up in great piles near the tracks, whence it may easily be loaded in the spring when the ice surrenders its grip on Lake Superior. Underground mining is adopted when the ore body lies so deep below the surface that the cost of removing the top soil would be prohibitive. Too expensive. In such cases a shaft is sunk to the lower level of the ore body, where a pump station Place for pump used to remove water from the mine. and ore pocket Place where ore is accumulated before being hoisted to the surface. are built. From this pocket a system of drifts or tunnels are run to all limits of the lode Ore deposit. that it is intended shall be mined. This accomplished, a second system of drifts is laid out at the top level of the ore body, which coincide with the drifts below, and winzes Vertical shafts between levels of a mine. or chutes Shafts for moving ore from higher to lower levels in a mine. are pierced through at given intervals from the upper to the lower levels. Mining starts on the upper level, the ore being dropped down the chutes to the lower level, where it is caught in small pockets provided with radial doors or gates. Barriers that come together at a central point. Electric trains, operating on the lower or tramming level, pick up this ore and carry it to the main pocket. This in effect is a great bin into which the side-dump cars vomit their accumulated loads. From the pocket the ore is run into iron buckets called " skips," Buckets or cars used to move ore to the surface. and hoisted to the surface. In brief, these are the two basic principles of mining employed on the Mesabi. Although simple enough in description, the actual art of mining is fraught with both danger and physical hardship and is technically complex to a high degree, especially in connection with underground work. |
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