2020-09-02_REVISION - C1981010 (3)

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pits. A sepr,-Irate item Wzls inselled into the Direct Costportioll of the IT 10 -Appei.idlx A Suininary (J'able A-1), whiell includes the additional costs oftopsoil p1acenieiit<,,uid revegetation for the entire 206.7 acres, 80.7 acres to be I'Lilly reclalitied and 126.0 acres of'RNYBR. '"Flie swine unit costs and nicthodology used. f the C' 11"Ces PR9 Bond. IYBR adjustii-ient was also employed hi the PR 10 cost adjustmell.t. "I'llc revised PRI 0 Bond estimate is included. Rule 4.09.1(7). Disposal of Excess Spoil DRMS August 2020 The Division of Reclamation, Mining and Safety (DRMS), has reviewed Evaluation and J Pit S z1fty &port bv A a 'to Aysoeiatev, Inc. dated. May 26, 20-19 for poil Pile Stah * --g_pi the Trapper Mine Permit Revision Pry -10. 4. In the Conclusion and Recommendations section of the report, the Operator states the spoil piles will be constructed in small lifts (20-40 feet) to allow for better compaction of the spoilparticles. Pursuant to Rule 4.09.1(7), please explain how the spoil piles will be concurrently compacted to ensure mass stability and -prevent mass movement. 5. Please provide the Rockscience Inc. slope stability analysis data for the Agapito Associates, Inc. geotechnical evaluation of the I and J Pits Spoil Piles to allow the Division to duplicate the analysis with Clover Technology's Galena software for verification purposes. Please include the profile geometries and the material properties used in the stability analysis, preferably in paper and electronic forms. Trapper Response to Comment 4: The SPO -11 piles will be dumped in 20 -foot lifts for the most part with the large overburden trucks provid' .119 the required compaction for the layers of f"ill. To sort the rock required for the underdrain taller dump faces faces, up to 40 feet tall, will be utilized to collect the rock. Even allowing for this tatler ffice, the con-ipaction provided during this Process allows for safety factors above 1.75 at the worst case, exceeding the 1.5 criterion. Trapper Response to Comment 5- The profile geometries are included separately as DX F files so that tlicy n -lay be opened as digital file s and measurements taken from them. They are called A Section through D Section and their material properties are included in'J'able 1, Summary Numerical Model Input Parameters, Page 4 of Agapito Associates, Inc. report 'R.e.- Evaluation ofl- and J -Pit Spoil Pile Stability, Trapper Mine. Rule 4.23.2 Auger Mining DRMS August 2020 DRMS notes that as per the above referenced rule, auger mining shall maximize coal recoverability of remaining reserves after completion of mining. DRi S finds that there may be areas of undisturbed coal left in unmined sections that are in excess of 2500 feet apart. Given that the ownership is the State of Colorado with a Trapper Lease, please demonstrate: 6. Distances between centrolds of coal sections meet the requirements of the above mentioned rule 7. That undisturbed areas of coal are a minimum of 250 feet wide between