Laserfiche WebLink
• <br />SUBSIDINCE HANDBOOK <br />BUILDINGS <br />Introduction <br />on site inspection and aerial photo evaluation has identified 33 buildings in the <br />permit and adjacent area. 24 buildings have been identified within the permit <br />area (see Map No. 9-7). For specific information on buildings, see Volume 3, <br />Table 11. No buildings will be undermined during the initial permit term. <br />Lease CnC-37210 states "The lessee shall consult with all owners of oocupied <br />dwellings and maintain or, with the owner's consent, adjust the designated 300- <br />foot buffer zone in order to mine near private dwellings located on the lease." <br />Solid coal blocks of 300-foot radius are left below all buildings, whether <br />oa~upied or not, within this lease. <br />Worst Case Damage <br />No damage to buildings in lease ~C-37210 areas with less than 760 feet of <br />overburden cover is anticipated because solid blocks of coal with 300 ft. radius <br />around the buildings will be left. Utilizing the conservative angle-of~lraw of <br />21.5°, the horizontal extent of subsidence is calculated to be 300 feet at 760 <br />feet of cover. CWI monitored and evaluated subsidence effects in the initial <br />permit term. Detailed surveying and analysis conducted by CWI determined the <br />angle-of-draw to be 20° and 16° for the respective panels studied. COVCC <br />continues to monitor subsidence for consistency with previously established <br />• findings. After evaluation of the site specific subsidence data, partial <br />extraction or other alternative mining techniques may be proposed to mine within <br />the 300 foot buffer zones. Building owner consent to alternative techniques <br />within the 300 foot buffer zones will be required prior to implementation. <br />Currently, solid blocks are maintained below all buildings within the COC-37210 <br />lease area. <br />Three occupied dwellings occur within the CbC-53356 lease area. Worst case <br />damage is anticipated to be very slight or negligible at these locations given <br />the significant overburden depths in the area (refer to Volume 3, Subsidence <br />Study, Plate 16). A miniminn of 2000 ft. of overburden depth occurs beneath each <br />occupied dwelling in this lease area. <br />Pre-Mining Monitoring <br />An initial inspection and subsequent analysis of buildings will be made prior to <br />mining within the area potentially affected by subsidence as defined by the <br />conservative angle~f-draw (21.5°) and the existing cover depth. The inspection <br />will be conducted with the owner of the building. The inspection will docim~ent <br />the pre-mining condition of the building and will describe and record any <br />existing structural, mechanical, or physical defects or conditions which prelate <br />the inception of any mining activity. Subsidence monitoring stations will be <br />established at each potentially affected building and spatial coordinates will <br />be established and referenced to a stable point outside the zone of potential <br />mine influence as defined by projecting the accepted angle~f~iraw (21.5°). <br />MR 93-87 Revised 09/30/93 <br />