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formations and healing of the cracks would be faster in them than bedrock formations or in <br />colluvial soils covering the ridges. Any pond disrupted by subsidence could easily be <br />repaired at low costs and in a short period of time. <br />2.5 LANDSLIDES <br />There are no criteria available on how subsidence can influence the landslides that <br />have been identified within the mining area. Although mining practice recommendations <br />have been made for an outcrop barrier to prevent the possibility of landslide creation or <br />reactivation by subsidence. <br />Large and old landslides identified by Junge (1978) will not, in all probability, be <br />influenced by subsidence. Their origin is related to different climatic conditions. The <br />renewal of their deformations under present climatic conditions is considered improbable <br />under the influence of subsidence. <br />In our opinion, only recent landslides, concentrated in areas close to the D -seam <br />outcrop could be effected by mining. Renewal of their deformations would more probably <br />be related to potential failures of outcrop barrier pillars and chimney collapse rather than to <br />trough subsidence. As discussed previously in the report, subsidence near the outcrop <br />could cause new landslides in any mined area close to the coal outcrop; the prescribed <br />outcrop barriers are designed to prevent any renewal of these slides or the triggering of <br />new slides due to subsidence. <br />Any surface facilities construction on unstable, steep slopes of the tributaries or <br />within the old landslides could cause new sliding or renewed deformations of old landslides <br />when improperly designed. <br />3.0 SUBSIDENCE ZONING <br />3.1 ZONES OF MINOR SUBSIDENCE IMPACT <br />No subsidence impact is expected in those areas where there is a thick overburden <br />cover. An overburden thickness in excess of 1,000 feet has been selected to define areas <br />of low subsidence impact, as shown on Map 27. <br />PR -14 -30- 06/14 <br />