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Memorandum <br />Rock Logic <br />onsulting LLC <br />Date: 5 December 2011 <br />To: Jim Abshire <br />Joe Brinton <br />Bill Bear <br />From: Brad Lindsay <br />Subject: Fall 2011 Subsidence Crack Mapping <br />Rock Logic Consulting <br />PO Box 544 • Cedaredge, CO 81413 <br />Phone: (435) 851 -9044 • rocklogicconsulting @gmail.com <br />Brad Lindsay • Consulting Geologist <br />Field Survey <br />A thorough field survey above the B10 longwall area was conducted in November 2011. The mined <br />B10 panel runs north -south west of terror creek and west of a power transmission line. The center of <br />the panel underlies mildly sloping terrain with both ends underlying steeper topography. Traverses <br />over most of the panel were hiked to observe visual evidence of subsidence. Thick brush, cliffs, and <br />thin snow on north facing slopes existed making observations in a few areas difficult. A GPS unit <br />was utilized in track mode to record the path of all traverses and locations of cracks observed. Each <br />new crack was photographed and the orientation, length, width, and vertical displacement <br />were measured. <br />Observations <br />Subsidence cracks were located in 21 different areas on the surface. Cracks occurred over most the <br />panel. More cracks were observed on the west side of the panel. Few cracks were found on the east <br />side of the panel. As usual, many cracks were discovered along fence lines and trails where the <br />ground is bare. The attached map shows the path that was hiked and location and approximate size of <br />cracks encountered. <br />Files <br />Crack measurements and field notes are recorded in an Excel file (Subsidence Crack Mapping Fall <br />2011.xls). The AutoCAD map (Subsidence- Crack -Novi l- source.dwg) was updated with the track <br />surveyed and lengths, orientations, and locations of new cracks observed. Digital photos of <br />the cracks are attached. <br />