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Fall 2007 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />• <br /> <br />• <br />Figure 34. April 2007 view of crack 3 zone at Apache Figure 35. April 2007 view of crack 4 zone at Apache <br />Rocks. Rocks. <br />The cracks trend primarily N65-75°E, but locally diverge to N4Q°E, N80°E, and E-w'. The <br />overburden depth to the B-seam is about 1,3>0 feet. More cracks were observed soon after <br />mining than are no~v present. Some of the smaller crack, iil the Ilarthertllllast part Of the Illltlal <br />crack area have closed, ur healed and sealed, a year or two after they formed. There currently are <br />essentially five individual cracks or crack zones aver a lateral distance of approximately 2~0 feet. <br />From north to south, the maximum widths of the individual cracks or crack zones, the centers of <br />which average 70 feet apart, are as follows: <br />Crack numher I cone. I.5 inches (Figure 32) <br />Crack nwnbcr 2 zone. ?.5 inches (Figure i ~) <br />Crack number ~ zone. 4.0 inches (total width of several branching cracks) (Figure ~-t) <br />831-032.780 Wright Water Engineers, Inc. Page 48 <br />November 2007 <br />