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In 2000, B&B Mines, Inc. commissioned the demolition of the remaining mill structure. The demolition debris was buried under a layer of natural hill-slope material(CDPHE, 2002). The fine-grained tailings pile located at the mill site was closed in place by grading the tailings and covering the material with river cobbles derived from the dredge spoils in the Swan River drainage adjacent to the site_ A layer of topsoil capping material was imported and spread over the cobbles. A seed mix of unknown composition was planted and the cover was fertilized. 6. SITE CHARACTERIZATION Site characterization activities were undertaken by ABC in June 2000 and CDPHE in the late summer and early fall of 2000. Investigations prior to 2000 were limited in scope (CDPHE,2002). The site characterization information presented below is drawn primarily from CDPHE(2002),with data from ABC(2000)incorporated as appropriate. Citations to primary references are provided as they are shown in CDPHE (2002). A complete copy of the Targeted Brownfields Assessment/Engineering Evaluation and Cost Analysis for the IXURoyal Tiger site (CDPHE, 2002)is included as Attachment B to this document. A complete copy of the report prepared by ABC in 2000 is not available, and thus is not included as an appendix to this work plan. 6.1 Physical Geography Much of the topography of the Breckenridge mining district can be described as hilly. The current topography is derived from the weathering of landforms affected by glaciation in the past. Evidence for glaciation in the area is largely depositional and is visible in the deposits of morainal materials on the valley sides and,where not disturbed by past dredging activities,on the valley bottoms. The aggraded Swan River channel is, in some places,elevated aver 70 feet above the former bedrock-controlled riverbed (Ransome, 1911). The Swan River Valley in the vicinity of the 1XURoyal Tiger site consists of a single drainage that occupies a wide valley trending to the northwest. The site area exhibits moderate fluctuations in topography coupled with approximate 300-foot elevation gains over short distances along the valley walls. The elevation of the IXURoyal Tiger site ranges from about 9,700 ft amsl at the site to about 10,000 ft amst at the collapsed upper workings(CDPHE,2002). Except in those areas disturbed by past dredging activities,the Swan River Valley near the IXURoyal Tiger site is moderately to well vegetated. Vegetation along the valley walls consists largely of a mixture of aspen and coniferous forests with high mountain wetlands. Meadows occupy the undisturbed, low-lying areas within the valley(CDPHE, 2002). 6.2 Geology Bedrock in the vicinity of the IXURoyal Tiger site consists of Cretaceous shale, limestone,and quartzite. Spec members present in the area include elements of the Pierre Shale,Niobrara Formation, Benton Shale,Jurassic shales and sandstones inclusive of the Morrison Formation,Permian and Pennsylvanian shales of the Maroon and Weber Formations,and Tertiary porphyry and quartz-monzonite porphyry. Much of the mining occurred along mineralized veins associated with contact-metamorphosed iXURoyal Tger VCUP Application Myy+^ ,. -- Page 13 of 33