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RESPONSE: It should be noted that the stability evaluation completed in 2012 of the ECOSA7 considered the facility and foundation soils as completely drained(Adrian Brown, 2012), and the data in Plate 12 of that report indicates that the colluvium material essentially is unsaturated beneath the entire ECOSA facility. The quote referenced by DRMS is misleading and refers to short-term conditions after large storm events. The colluvium will be unsaturated during steady-state conditions as the saturated hydraulic conductivity of the material(approximately 10-5 cm/sec) are sufficient to conduct any percolation into the underlying bedrock. NewFields believes modelling this layer as completely saturated is too conservative. Nonetheless, the stability evaluation will be revised to assess the sensitivity of the calculated FOS to saturation in the colluvium layer. 41. Appendix 6,p. 4, Bedrock. • The assumed cp (friction angle)and cohesion values are 45 degrees and 5,000 psf(-35 psi), respectively. Based on a comparison of Drawing C-7,District Geology(Vol. I) and the ECOSA location on Figure 2 (amended AM-11)the possible bedrock underlying the ECOSA is phonolite, feldspar bearing—plagioclase phonolite, and/or Cripple Creek lapilli breccia. A comparison of mean strengths in Table 6-1 of Appendix 5 (Vol. 11I) suggest the cohesion value used is conservative (i.e., less than that obtained from testing), but the 45 degree friction angle is much higher than the highest mean value (for RQD=90%) in Table 6-1. The level of uncertainty for this particular bedrock material suggests the use of strength parameters in the medium range (e.g., RQD = 50 %)and FOS from DRMS Table 1 for"Generalized,Assumed, or Single Test Strength Measurements". Please use consistent strength parameters or further justify the use of 45 degrees and 5,000 psf. RESPONSE. We will revise the stability evaluation to consider bedrock strength parameters that are consistent with those reported in the pit slope design report. It should be noted that the stability evaluation completed in 2012 of the ECOSA considered the bedrock as an "unbreakable"material with infinite strength. Based on our experience with these type of facilities, the underlying bedrock will not control slope stability and this modification to the bedrock strength will have no influence on the global stability. 42. Appendix 6, Paragraph 2.4, Stability Evaluation Results • The ECOSA is an engineered environmental protection facility(EPF). The analyses for Sections 1 and 2 (considered critical structures) need to be re-evaluated based on Comment Nos. 40 and 41 above. The Section 3 (non-critical structure as slope failure would not be expected to directly have an offsite impact)pseudo-static analysis, resulted in a FOS of 1.0. This is unacceptable for during operations or after reclamation. The Division will not approve an increase in the height of the ECOSA if appropriate FOS's (based on DRMS Table 1) cannot be achieved. RESPONSE: NewFields agrees that potential failures of western aspect slopes that face towards the mine should be considered "non-critical"per DRMS Table I and the associated minimum acceptable FOS for this type of slope designation applies. 43. Appendix 6, Figure 5, Section 3 • Please explain why the east slope is steeper(2.5HA V)than during operations (2.9H:1 V). 'Adrian Brown(2012). "Cresson Project, East Cresson Overburden Storage Area Evaluation,"Project No. 1385E, February 24. Page 20 of 30