Laserfiche WebLink
vertical, and were oriented normal to the bedding plane which dips more than 30 degrees to the west. <br />Fracture surfaces appeared weathered. Subsidence fractures would be expected to be neaz vertical <br />(oriented at an oblique angle to dipping beds) and would have a fresh appearance, as they would have <br />formed within the last 30 years in this area. Based on the observed orientation and appearance of <br />fractures, the fractures aze considered to have formed within an ancient tectonic or burial stress field, <br />rather than a recent stress field created by mine subsidence. <br />The absence of surface subsidence features may indicate stress from subsidence was accommodated <br />within the stratigraphic section that lies between the mine workings and the overlying land surface. <br />Fractures propagating upward from the workings could have terminated in relatively ductile <br />interbedded layers of shale and sandstone within the overburden. <br />Reclamation Success <br />The two flumes on Middle Thompson Creek were removed approximately 5 years ago, according to <br />past DRMS inspection reports. Reclamation of the two sites has shown long-term success (see the <br />following photos). <br />The observations made during this inspection of the reclaimed flume sites and the undermined areas <br />would support a finding that the mine operator has met the requirements for Phase III (final) bond <br />release. <br />The operator has previously submitted an adequate repair plan for the refuse pile sinkholes and the <br />Mine No. 3 portal backfill that were found during the inspection on 4/17/07. After those repairs aze <br />made, DRMS will inspect the repairs and will evaluate the need for extending the revegetation liability <br />period in those areas. The two piezometers at the base of the refuse pile remain to be reclaimed, <br />which may be completed immediately. Signs and markers will need to be removed afrer DRMS has <br />issued a proposed decision to approve final bond release. The signs and markers include disturbed area <br />markers at the main mine site, permit boundary markers at the loadout, and the mine i.d. signs on <br />entrances to the permit area from public roads. <br />4 <br />