APPENDIX B SOUTH EMBANKMENT DAM-TYPE SELECTION STUDY (Pages B-1 to B-34) VA101-343/6-2 Rev 0 January 27, 2011 KKIITTSSAAUULLTT PPRROOJJEECCTT DDAAMM DDEESSIIGGNN AALLTTEERRNNAATTIIVVEESS SSTTUUDDYY SOUTH DAM TMF 15 OCTOBER 2010 B-1 of 34 OOUUTTLLIINNEE • Tyyppes of Water Retainingg Dams • Water Retaining Dams for TMF Site • ACRD Concept Familiarization • DDams EEvalluatedd ffor SSouthh DDam B-2 of 34 TYYPEESS OOFF WWATEER REETAINNINNGG DDAMMSS Concrete Faced Rockfill Dam (CFRD) Zoned Earthfill/Rockfill Dam Geomembrane Faced Rockfill Dam (GFRD) Asphaltic Core Rockfill Dam (ACRD) Roller Compacted Concrete Dam (RCC) B-3 of 34 COONNCREETEE FFACEEDD ROOCKKFFILLLL DDAMM B-4 of 34 CFFRDD PROOSS ANNDD COONNSS Pros  SSllooppee pprrootteeccttiioonn aaggaaiinnsstt wwaavveess aanndd iiccee  Rockfill zone is unsaturated and slopes can be constructed steeper that earth fill dams(1:3H to 1:5H:1V versus 2H to 22.55HH::11VV))  Plinth and grouting can take place independently of the other dam construction CCoonnss  Design for leakage through opened joints and tension cracks.  Large compression cracks can occur in high CFRD`s in narrow valllleys  Cannot provide storage during construction  Not a common construction ppractice in BC and Canada B-5 of 34 ZZOONNEEDD EEAARRTTHHFFIILLLL//RROOCCKKFFIILLLL DDAAMM B-6 of 34 EEARTHHFFILLLL DDAMM PROOSS ANNDD COONNSS Pros  WWiiddee eeaarrtthh ccoorree aanndd ffiilltteerrss pprroovviiddeess ssaaffee ddaamm eeaarrtthhqquuaakkee resistance  Earth core design most economic if suitable borrow areas are wwiitthhiinn rreeaassoonnaabbllee ttrraannssppoorrttaattiioonn ddiissttaanncceess  Earthfill dam have been used for many years and the efficiency of this type of dam is well documentted  KKnnoowwnn aanndd ccoommmmoonn ddeessiiggnn iinn BBCC aanndd CCaannaaddaa Cons  Difficult to construct in rainy weather  Largest quantity or fill required  Foundation treatment in the core zone to avoid erosion of the core material along the fractured rock surface  More vulnerable to overtopping during construction B-7 of 34 GGEEOOMMEEMMBRANNEE FFACEEDD ROOCKKFFILLLL DDAMM B-8 of 34 GGFFRDD PROOSS ANNDD COONNSS Pros  RRoocckkffiillll zzoonnee iiss uunnssaattuurraatteedd aanndd ddoowwnnssttrreeaamm ssllooppee ccaann bbee constructed steeper that earthfill dams(1:3H to 1:5H:1V versus 2H to 2.5H:1V)  PPlliinntthh aanndd ggrroouuttiinngg ccaann ttaakkee ppllaaccee iinnddeeppeennddeennttllyy ooff tthhee ootthheerr dam construction  Membrane flexibility to accommodate rockfill deformations CCoonnss  Vulnerable to impacts, ice loads, sabotage, effects of weathering and aging.  RRequiires partiiall or ffulllly coveredd protectiive llayer thhat increases cost  Cannot provide storage during construction B-9 of 34