2018-09-07_REVISION - C1981010 (2)

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Trapper Response to Comment 28: As a result of the landslide of October 2006, K Pit, which was directly in the slide area, was extensively evaluated from a geotechnical perspective to develop a mining plan that would ensure the safest possible operation for personnel and equipment. In May of 2009 Trapper's Geotechnical Consultants conducted a study that suggested that Trapper should construct a toe buttress at the northern boundary of the K pit. This buttress was expected to enhance the stability of K — Pit mining and was included in the PR -7 Permit Revision document; however, later modeling, based on updated information, indicated that the buttress would not stabilize the slopes for the mining below the KIL-10 cut. It was determined that the stability of this area would be better achieved by reducing the slope through pre -stripping cuts KI L-13 and K1 L-14 to the I -Seam. Trapper followed this guidance which did not require the construction of the toe buttress. A summary of the primary reasons why the toe buttress information was not included in the PR9 application are as follows: • As mentioned, later modeling based on more accurate information led the Geotechnical consultants to the conclusion that the toe buttress would not enhance the stability of the mining operation and was therefore not recommended, and not constructed. The absence of the toe buttress had no relevance and was therefore deemed unnecessary to the 2018 through 2022 Mining Plan (PR -9 application). • The original recommendation for the toe buttress was based on mining stability and not spoil disposal stability (as per rule 2.05.3(6) b), and therefore was not pertinent to the PR -9 application. • K Pit has been safely and successfully mined and is presently in the process of being backfilled and reclaimed, thus the toe buttress language has no relevance to the 2018 through 2022 Mining Plan (which involves L Pit and N Pit development) and was therefore not addressed in PR -9. Rule: 2.05.4 (2d, e) Reclamation Plan The above rule is adequately addressed. DRMS notes that the cover letter submitted with the revised pages states that Trapper is proposing to modify the shrub density standard to include a 700 stems/acre alternative standard. 29. Please insert a discussion of this alternate standard on page 4-101 where the success standards are outlined. Trapper Response to Comment 29: Please refer to the Comment 10 response. Please get back to us with any questions. comments or concerns. Sincerely, ,Y/ & Forrest Luke Environmental Manager Trapper Mining Inc.