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File:RetreatingLongwall.png

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Summary

Description
English: Origional caption: "Fig. 36. Block system of Retreating Long-wall, West Virginia." Plan of a multi-panel longwall retreat mine, circa 1917. Edge detection has been used to convert the figure to a line drawing.
Date
Source Percentage of Extraction on of Bituminous Coal with Special Reference to Illinois Conditions, Engineering Experiment Station Bulletin No. 100, University of Illinois, page 115.
Author C. M. Young

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June 1917Gregorian

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Date/TimeThumbnailDimensionsUserComment
current15:54, 20 August 2009Thumbnail for version as of 15:54, 20 August 2009768 × 821 (60 KB)Douglas W. Jones{{Information |Description={{en|1=Origional caption: "Fig. 36. Block system of Retreating Long-wall, West Virginia." Plan of a multi-panel longwall retreat mine, circa 1917. Edge detection has been used to convert the figure to a line drawing.}} |Sour

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