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Compile results and generate depth profiles of soil Ra-226 versus sample depth. Ten percent <br />of these samples collected as aliquots will be sent to a vendor laboratory. <br />A similar procedure may be employed for uranium using XRF screening measurements. Any <br />XRF analyses will be done on site using a hand-held unit for screening purposes, recognizing <br />that moisture content and material particle size may be limiting factors in the reliability of <br />such measurements. In general, solid phase source term materials within the alluvial fill are <br />expected to have a clear gamma signature that can be readily measured with gamma <br />detection instruments. <br />Use analytical results from the above measurements to identify any layers of interest and, if <br />possible, create three-dimensional schematic maps of possible subsurface contamination. <br />5. Select representative sample aliquots to send to the laboratory for testing, including uranium <br />and Ra-226, along with EPA Method 1312 (analysis by Synthetic Precipitation Leaching <br />Procedure). <br />6. Develop a report covering the "toxic forming" potential of alluvial fill source term materials <br />and include a related assessment of potential impacts (hydrologic and any others) of disposal <br />of this material in the mine workings from which they originated, via the Minnesota portal. <br />7. If supported by the overall assessment, submit a Technical Revision request to dispose of this <br />material in the Minnesota portal, and include provisions for the excavation work, re-grading <br />and final re-vegetation. <br />8. If disposal of source term material in the Minnesota portal is not supported by the <br />assessment, propose alternative disposal options and related assessments to the DRMS. A <br />potential alternative disposal option includes transport to the Canon City Milling Facility for <br />disposal in the tailings impoundments (as was commonly done in the past). If conceptual <br />consensus can be reached on an alternative disposal strategy, submit a different Technical <br />Revision request accordingly. <br />Items 1 and 2 above have already been completed, and an initial sampling design and plan <br />has been mapped in the figure below. Sampling locations may be modified based on site <br />conditions and assessment of results as the project progresses. <br />It is expected that the field work portion of this project will take several weeks. Review of <br />analytical results, technical assessments and reporting are expected to take several months to <br />complete. <br />2