2017-09-26_GENERAL DOCUMENTS - C1981019

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Preliminary Report for Data Recovery at Sites MK -1-082317 and MK -2-082317 Colowyo Coal Company 1.0 INTRODUCTION Colowyo Coal Company L.P (Colowyo) is constructing the haul road and facilities associated with their Collom Expansion Project (Project). As part of the Project, Tetra Tech has been contracted to provide archaeological monitoring services for Elk Ridge Mining and Reclamation (Elk Ridge) on the behalf of Colowyo. The High Potential Area (HPA) archaeological monitoring has been conducted in accordance with Exhibit 5, Item 3 -Cultural Resource Protection Plan for the Collom Mine Expansion filed by Colowyo to the Office of Surface Mining, Reclamation, and Enforcement (OSMRE) as part of their mine permit. On August 23, 2017, two prehistoric sites (Sites MK -1-082317 and MK -2-082317) were discovered during topsoil stripping activities by the Tetra Tech archaeological monitor along sections of the haul road at the crossing of Moffat County Road 51 (Figures 1 through 3). In accordance with Exhibit 5, Item 3; ground stripping activities were stopped within 100 feet (ft) [30 meters (m)] and each site was flagged for avoidance. Tetra Tech produced a notification report for Colowyo to submit for review to OSMRE; Colorado Division of Reclamation, Mining, and Safety (DRMS); and Office of Archaeology and Historic Preservation (OAHP). The sites could not be avoided by the Project and face complete removal as part of construction activities. OSMRE in consultation with DRMS and OAHP determined the Project would cause an adverse impact on both sites. The impacts would be the removal of the additional data potential documented at each site in the form the man-made feature intact portions and additional subsurface potential in the immediate area. The agencies requested the development of a historic properties treatment plan (HPTP) to mitigate the adverse effects. Tetra Tech produced the HPTP and it was reviewed and approved by Colowyo, OSMRE, DRMS, and OAHP (Karpinski 2017). The field work portion of the HPTP was executed by Tetra Tech from September 14, 2017 to September 21, 2017. The following preliminary report is to provide OSMRE, DRMS, and OAHP the information needed to concur field work efforts are completed, information potential has been exhausted, and Colowyo can proceed with construction activities within the two site boundaries prior to completion of the laboratory analysis and final technical report. 2.0 DATA RECOVERY FIELD WORK RESULTS The executed field work at each site conformed to standard archaeological practices intended to yield information in support of the research design detailed in the HPTP (Karpinski 2017). The field work tasks were to A) determine the vertical and horizontal extent of the subsurface deposits at each site; B) recover data from the identified features exposed by mechanic ground stripping activities; C) collect data from any additional encountered subsurface component(s) identified at either locality; and D) determine the integrity of all encountered components and identify what, if any, taphonomic processes have impacted the cultural component(s). 2.1 Evaluative Testing Tetra Tech Principal Investigator (PI) directed evaluative testing to define each site's full horizontal and vertical extent specific to each site's location as outlined in the HPTP. Testing was completed using shovel test probes (STP) oriented in parallel rows with individual probes spaced 5 m (16 ft) apart. STP's were 30 centimeters (cm) in diameter hand dug holes excavated in 10 cm arbitrary levels below ground surface. All excavated sediment was sifted through 1/4" screen. Site MK -1- 082317 has no intact sediments remaining; however the area around the features was tested to determine if potential intact cultural component(s) were present. Site MK -2-082317 has intact sediments to the east beyond the project disturbance boundary that were tested. The results of the testing at each site are discussed in Section 3.0. Tetra Tech September 29, 2017