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Ivtemorandum to Kathy Welt <br />' August 28, 1997 <br />Page 3 <br />2. CDIvfG Location No. 2: Northwazd trending crack or cracks as much as 3 <br />inches wide, 5 inches deep, and 15 feet long aze located above the western limit <br />of longwall Panel 8 in SE%, Section 23, T1S, R91W. The cracks occurred in <br />the spring or eazly summer of 1996; there is now little or no evidence of the <br />cracks at all; the cracks aze healed for all intents and purposes. <br />3,4. CDIvIG Location No. I: Numerous cracks aze located in two azeas about 200 <br />feet apart neaz the north boundary of longwall Panel 8 in SW'/. Section 24; <br />cracks aze located neaz the west boundary of what appears as an old landslide on <br />the 1975 IntraSeazch air photos. In July 1996, cracks were reported by MCC to <br />be as much as 5 feet wide, 6 feet deep, and 200 feet long and commonly trend <br />nor[hwazd; trees and brush appear to lean in various directions. Cracks have <br />sloughed, filled, and healed considerably in one yeaz, roughly one-quarter to <br />one-third of their reported width, depth, and extent in 1996. <br />5,6. CDMG Location No. 4: Numerous cracks of various trends, widths, and lengths <br />aze located in two azeas above the south boundary of longwall Panel 8 in SE'/,, <br />SW'/<, Section 24. Many of the cracks trend generally northwazd, but a few <br />trend northwest and northeast. Cracks aze located within what appeazs as a <br />small, old landslide; awater-filled depression, which appears to have formed by <br />back-slope rotation, is located 200 to 400 feet east of two of these locations. <br />MCC reports that there has been historic (prior to mining) movement of this <br />slide. The cracks initially were as much as 3 feet wide, 3 feet deep, and 100 feet <br />long. Maximum width and depth on this visit, about a year later, is roughly one <br />fourth to one third of this value. The cracks had therefore healed considerably <br />by sloughing and filling during the past yeaz. <br />7,8. CDIvfG Location No. 5: The lazgest and most extensive cracks occur in this <br />azea, which is located 200 to 400 feet east of the depression discussed for <br />location number 4. The cracks aze located near the southeast margin of the old <br />landslide feature discussed at location number 4. The surface is offset as much <br />as 5 to 6 feet towazd the depression. Another crack sequence has produced a <br />trough-like feature as much as 1~-feet wide, 4 to 5-feet deep, and more than <br />100-feet long. The trough-like feature trends roughly east-west towazd a <br />historic landslide scarp (reported by Dames and Moore [1993]). A bulged and <br />cracked azea about 50-feet wide is located about 50 feet northwest down the <br />road from the widest crack; the bulge appeazs to be about 3-feet high. This azea <br />is located partially above Panel 9, but is also within the area of mining influence <br />of Panel 8. Fresh cracks were locally observed among older, nearly healed <br />cracks even 13 months after Panel 8 mining was completed below, indicating <br />renewed and/or continuing landslide movement. <br />