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2.0 DESIGN CRITERIA <br />-- The evaluation makes the following assumptions with respect to <br />--• .-=~;=design criteria: <br />-_. 1. The existing pads are considered to be of acceptable stability <br />and design based on the regulations under which they were <br />- - constructed (the 11/30/83 version). <br />2. The pad expansion will be designed using the regulations fort <br />coal waste banks (Section 2.05.3(8):Coal Nine waste and Non- <br />Coal Processing Waste, and Section 4.10: Coal Y.ine Waste <br />Banks). This assumption follows from the fact that the pad <br />expansions will be const_-acted from material from the <br />development of the access tunnels. In these regulatiens, <br />"underground development waste" is defined as "coal mine <br />waste" [Section 1.04(22a)J. The design w111 conform tc: <br />• appropriate subdrainage <br />e slope protection against erosion <br />• minimum static safety factor of 1.5 <br />• approved lift thicknesses and compaction <br />• slope no greater than 2h:ly (50$) <br />. covered with an approved 16" layer cf topscil <br />3. The design of the slopes of the pad expansicns will corfo:W to <br />`..he recuirements for permanent reclamation of these slopes, zs <br />•^.~_`~ set for`..h in Section 4.14.2: <br />• slopes will approximate pre-mining slopes <br />• minimum static factor of safety is 1.3 <br />• slope terraces of less than 20 feet width zre zllowed <br />• terrace outslapes shall not be steeper than 2T_:1v (50~) <br />These slopes will be revegetated immediately after placement, <br />which will allow the option of either lea~•ing them ir. place at <br />the end of the project, or excavation and placement bacr in <br />the tunnels, whichever is considered mcre aestheticall~~ <br />pleasing. <br />i <br />-~ ..~Grian Brown consultants -2- <br /> <br />