Laserfiche WebLink
Predicted Subsidence Phenomena <br />Snowmass Coal Company plans to use longwalt mining and full extraction <br />room and pillar mining to maximize resource recovery. Asa result, sub- <br />sidence is expected to occur. The development of this planned subsid- <br />ence will result in both horizontal and vertical movements within the <br />overburden rock mass. <br />Surface subsidence effects will consist of the development of subsidence <br />troughs and, possible, minor surface fracturing. It is anticipated that <br />the subsidence troughs wilt be broad and shallow, pifferential horizon- <br />tal and vertical movements may result in minor fracturing at the ground <br />surface. However, subsidence studies have shorn that these features <br />usually close up in a short period of time with no significant nor last- <br />ing effects (King, 1980). King (1980, p.100) states that "cracks oriented <br />parallel to the face....(closed) behind the face. At this time nearly <br />all cracks oriented in this manner have completely closed and there is lit- <br />tle evidence that they ever existed." <br />In order to verify the assumption that surface cracking 1s transitory, <br />visual monitoring will be performed in the DOE subsidence study area (sec- <br />ttan 4.6.1.6.4). This visual monitoring will be performed in conjunction <br />with the regularly scheduled surveys of the subsidence net, <br />The ongoing hydrolo9lc study will be utilized to insure that the transi- <br />tory surface subsidence phenomena do not result in increased infiltration <br />• of surface water. <br />16 <br />(Revision JIlHE 1982 ) <br />