2017-09-11_PERMIT FILE - C1981019 (3)

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Cultural Resource HPTP for MK -1-082317 and MK -2-082317 Colowyo Coal Company The horizontal extent of the site appears to be limited to the features within the disturbance area. However, a potential exists for intact portions of the site to occur beyond the disturbance area to the east. The site is recommended eligible for inclusion on the NRNP. The site cannot be avoided; therefore Tetra Tech recommends data recovery be conducted for each feature, limited testing within and outside the disturbance area, and monitoring of remaining ground stripping at the location afterward. 3.0 TREATMENT METHODOLOGY Tetra Tech developed the following treatment methodology based on our prior experience working with similar sites throughout the region and in consultation with OSMRE. The structure of the methodology is also based on HPTP developed for Project site discovery BK -1-072617 (Karpinski 2017) which was approved by OSMRE, DRMS, and OAHP. 3.1 Evaluative Testing Scope and Methods The evaluative testing will take the form of shovel probe testing of the scraped sediments near the feature(s) and in intact sediments as appropriate. Tetra Tech does not believe any intact sediments exist within a reasonable vicinity of Site MK -1-082317; however, we will conduct limited testing adjacent to the identified features to determine vertical extent of the identified cultural component and to determine if an additional buried component(s) are present. Evaluative testing at Site MK -2-082317 will occur within the already disturbed part of the site to determine the vertical extent and if any additional cultural components exist. Testing will also occur in the intact sediments immediately to the east to determine the horizontal extent beyond the project disturbance boundary. Testing outside the disturbance boundary will occur only to establish the complete horizontal and vertical extent of the cultural component. Additional data recovery efforts (excavation units, feature recovery, mechanical stripping, etc.) will not be conducted outside the disturbance area as part of the HPTP. Shovel probe testing will be oriented in parallel rows with individual probes spaced 5 m (16 ft) apart. Shovel probes will be 30 cm in diameter hand dug holes using a spade shovel. Excavation will be conducted in 10 cm arbitrary levels below ground surface. All excavated sediment will be sifted through 1/4" screen. Any encountered cultural material will be collected, cataloged, and bagged with a proper identification and provenience information label. Each shovel probe will be completed to a depth of one 10 -cm arbitrary level into an identified residual sub -strata visible in the adjacent haul road base or at bedrock. All completed shovel probe locations will be GPS plotted and testing data will be collected on Tetra Tech's shovel probe test forms. Testing will begin closest to the discovery and extend outward. At least two sequential negative tests will be required to terminate shovel probe testing in any given direction. In addition to identifying the horizontal and vertical extent of the discovery, the testing will also identify any potential additional intact subsurface cultural resources. The testing results will directly inform the application of data recovery measures outlined below in Section 3.3. 3.2 Research Design Tetra Tech developed the following research design based on the cultural material discovered at the site; the Collom Expansion baseline work completed in 2005; archaeological experience working in the region; previously reported data pertaining to cultural resources in northwestern Colorado; and standard archaeological theory and method. Research questions presented here Tetra Tech August 31, 2017 9