Laserfiche WebLink
<br />-3- <br />The detail required of such descriptions will ul:v~ousiy v,u-y w.itii the scnL_ of <br />the operation and magnitude and si.,,niFicance of impact, nn sCruc~'uRr. ^~td. <br />resouces, occurring at the various possible levels of subsidence. la hi;;L <br />magnitude and significance situations developing [his plan ,gill be e::~r~rtely <br />complicated. In SiCUaC10R5 where significanre of :;tinctures and ._.,i;~irces are <br />small and overall subsidence minor, the development will be muc?~ icorc si^.~.;-1e. <br />Part (a) covers description of the b:sic mining plan and phases of the <br />wtderground operation designed to control subsidence. This description must, <br />by regulation, cover the scope of all underground unit operations of <br />excavation, materials handling and ground s~~pport. The detail to which su~:h a <br />description is presented should probably be consistent with the detail level <br />of part (b), as they are extremely interlinked. <br />Part (b) is the heart of the subsidence plan. It essentially requires <br />prediction of subsidence and plans to control and, as required, monitor the <br />surface effects of subsidence. Such an analysis may have [o be prepared by an <br />appropriately qualified professional. This portion of the subsidence control <br />plan must reflect the state-of-tlte-art of current subsidence prediction <br />[ethnology at a level of involvement consistent with the magnitude and <br />significance of possible effects to structures and rene:rable resource areas. <br />The analysis will require minor [o in-depth review of sm.a11-scale roc'-: <br />mechanics of [he affected rock materials (shear strength and compressive <br />strength parameters) and large scale structural and mechanical <br />characteristics such as faulting and fracturing. Laboratory and core drilling <br />data are important, and should be supplemented, as nece~s;iry and possible, <br />with historic observation of previous or present mining activity. <br />~s subsidence prediction is not a definitive science, the applicant ita~ be <br />required to verify subsidence projection techniques through operations <br />monitoring. In simple cases, it may be possible [u 3-point reference a p4:ne <br />on the surface area with existing structures or mnnuments. Ptore likely, <br />however, simple (2 or. 3) to sophisticated (regular pattern) subsidence <br />monument systems will be required, again depending on ti~a required 1c•:el of <br />de [ail. Simplistic systems can be installed. The anchoring of these must be <br />substantial to assure that movements are subsidence related and not d;:e to <br />normal ground movement. Such systems typically consist of prependicular rows <br />of drilled, caisson-type, concrete and rebar monuments above mine workings. <br />3egular monitoring of these monuments, by traditional surveying techniques, in <br />initial stages will help in design of future monitoring networks and <br />procedures, as required. <br />