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Coors Energy Company Keenesburg Mine—Phase III Bond Release Application Revegetation Success Demonstration 1 Introduction The information contained in this application includes results and analysis of 2021 and 2022 vegetation sampling. This information supports Phase III bond release for Reclamation Areas 23, 29, 30, and 31 totaling 30.6 acres. Figure 1 shows the location and extent of the Phase III application area within the Keenesburg Mine. Per approval from DRMS, Reclamation Area 23 was combined with Reclamation Area 29 in 2019 for vegetation sampling. This combined area is referred to as Area 29/23 in this report. 2 Revegetation and Bond Release History Reclamation Areas 23, 29, 30, and 31 were formerly part of the B Pit mining area. These areas were graded to blend into the undisturbed area to the west and the reclaimed mining and operational areas to the east resulting in a gentle, east-facing slope. Each area was backfilled and graded. Final revegetation seeding with the DRMS-approved permanent seed mixture in each area took place in the year shown in Table 1. Table 1: Reclamation Year by Reclamation Area Year Area Acres Seeded 23 0.67 2002 29 8.31 2003 30 9.68 2006 31 11.89 2009 Phase I bond release was granted for Areas 23 and 29 in 2004 with SL-02 and for Areas 30 and 31 in 2014 with SL-07. Phase II bond release was granted for Areas 23 and 29 in 2010 with SL- 05 and for Area 31 in 2019 with SL-10. Area 30 has not yet received Phase II bond release but has met the Phase II requirements as demonstrated in this application. 3 Vegetation Sampling The monitoring methods and revegetation standards used to evaluate these areas are those currently in effect under the Colorado Surface Coal Mining Reclamation Act(CRS 34-33-101) and the Keenesburg Mining and Reclamation Permit. Vegetation monitoring occurred on August 9— 13, 2021 and August 15—25, 2022 Monitoring coincided with maximum vegetation development of most plant species found in the reclaimed and adjacent native areas. 3.1 Sampling Design Thirty sample points were placed prior to going into the field using mapping software to create a square grid overlaid on each Reclamation Area being sampled. The sample points were located at the intersection of each square created by the grid. The grid size was adjusted to create the appropriate number of sample locations within each Reclamation Area. Sample numbers (1-30) were randomly assigned to each generated sample point along with a randomly generated azimuth (Figure 2 and Figure 3). A minimum of 15 vegetation cover samples were collected in each Reclamation Area with additional samples collected, if necessary,to meet sample adequacy per DRMS guidelines (DRMS 1995)up to a maximum of 30 samples. The maximum of 30 production samples were collected in each area. SL-12 2 May 2024