Laserfiche WebLink
2004 Geologic Hazard Field Observations <br />South of Divide Mining Area <br />Of the springs mapped, only the decreed Spring 21 and the spring located along Dry Fork and <br />above longwall panel E2 maybe impacted by longwall mining. The source of decreed Spring 21 <br />may be a local water-bearing zone in bedrock of the Mesaverde Formation, whereas, the source <br />of the spring along Dry Fork (above longwall panel E2) is likely to be a local water-bearing zone <br />in colluvium or alluvium derived from debris flows. <br />9.4.2 Water-Bearing Zones <br />Horizontal strain produced during subsidence may impact local water-bearing zones in bedrock <br />beneath the blanket of clay-rich sur£icial material, and also may impact local water-bearing zones <br />in surficial material, where permeable and satwated zones are stratigraphically positioned in <br />zones of tensile strain. Impacts may occur for long periods of time, where the water-bearing <br />zone is located above mine boundaries and barrier pillars-areas where permanent strain occurs. <br />On the other hand, dynamic strains and related cracks produced by subsidence above moving <br />longwall faces in a given area may be small or nil, and close when the longwall faces move out <br />• of the area of influence of this area. <br />Any mining effects on local on water-bearing zones can best be identified by monitoring changes <br />in flow and water levels in springs and ground water wells that are adjusted for seasonal <br />variations. <br />9.4.3 Ground Water Wells <br />u <br />The two monitored, ground water wells in the South of Divide mining area are located east of, <br />and near the mouth of Deer Creek (Map 1). They are located above or within the aeeas of mining <br />influence of, the barrier pillaz areas and haulageways of projected longwall panels E2 and E3. <br />Overburden depth to the E Seam is approximately 400 feet. The major source of the water in <br />these wells likely from colluvium and alluvium in the Deer Creek drainage. <br />831-032.621 Wright Water Engineers, Inc. Page 37 <br />November 2004 <br />