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<br />TABLE TWO -- BOULDER COUNTY <br />MINE NAME COMMENTS ON FEATURES <br />Matchless S~: Subsidence pit? Pit 20' long, 10' wide and 6' deep; trash filled; may be due to subsidence. <br />Champion) <br />Sunland) Sp: Subsidence pit. In 1964 an ovate pit 20' long, 10' wide, and 8' deep opened over the <br /> southern edge of the mine. Area has since been reclaimed and pit is no longer visible. <br />Mitchell S~: School shows some cracking in brickwork of garage and cracking across bricks in southwest <br /> corner of building addition. <br /> S2: Low, swampy area; some caliche crust; drainage does not appear to be natural. <br /> S3: Area appears to have some closed depressions, approximately 15' in diameter, 0.5'-1.0' deep. <br />Monarch #2 S: Subsidence? Turnpike has 0.5' depression at this point. Subsidence over the Monarch #2 <br />(Lucas) mine is one possible cause. Others are swelling clays and consolidation of highway fill. <br /> Numerous depressions, 3' to 15' across, 2' to 3' deep on top of mine dump; depressions may <br /> be due to subsidence or to consolidation of mine dump. <br /> Reclamation scheduled for Spring 1984: Backfillin9 the shafts with riprap and on-site <br /> waste material. All disturbed areas will be revegetated. <br />Murray Slope S: Subsidence pit cluster. Numerous subsidence pits 5' to 10' in diameter and 3' to 5' deep. <br /> Due to collapse over rooms of Murray mine. <br />New Ross S: Subsidence troughs and extension cracks. Subsidence troughs have formed over the ad its and <br /> air courses of a air courses of a number of the mines clustered in this area. Numerous <br /> extension cracks occur in the hill slopes overlying the shallow rooms of these mines. <br /> Reclamation scheduled Spring 1984: Backfillin9 the open ad it with riprap and on-site coal <br /> waste material. <br />Key to unique features symbols: Z Multiple mining zones <br /> * Mine opening information <br />Recl amation and/or plans -- Table Two S Subsidence features <br /> lists hazard abatement work F Mine fires <br />+ Discrepancy between two sources D Mine drainage -35- <br />