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2001 Soil Sampling: Seneca Mine, Hayden Colorado <br />• <br />Rock Fragments- Rock fragments average 5 percent and ranges 0 to 10 <br />percent. Rock Fragments are predominantly gravel size (2mm to 75mm) of <br />sedimentary origin, primarily sandstone. <br />Structure- The upper horizon in both sample pits are moderate coarse and <br />very coarse platy and sub-angular blocky. The resultant structure and depth <br />of the structure is consistent with a mechanically disked layer but is <br />moderately compacted. The lower topsoil horizon is strong coarse and very <br />coarse sub-angular and angular blocky structure. This indicates moderate <br />compaction. Vegetation analysis discussed below did not indicate that such <br />structure is presenting a problem to plant growth. <br />Consistence- The dry consistence of the upper topsoi! layer is hard.. Moist <br />consistence is friable. Consistence of the lower topsoil horizons is higher than <br />typical for textures of loam. Dry consistence is very hard. Dry consistence <br />indicates moderate compaction through the use of mechanical equipment for ; <br />soil redistribution. Moist consistence is friable to firm. Vegetation analysis. . <br />discussed below did not indicate that• such consistence is presenting a , . <br />problem to plant growth. <br />• Lab Data- Lab data is located in Appendix II. Both the upper and lower topsoil <br />horizons, differing only in their mechanical treatment, have the same chemical <br />properties, pH ranges 6.3 to 7.0 and averages 6.8 which is neutral. Organic <br />matter averages 4.5 percent and ranges 3.5 to 8.6. These results and a!I <br />other lab data indicates topsoil in all sample pits is suitable (Appendix III, <br />Table-2). <br />Subsoil- The same sample pits were sampled for subsoiUspoil from the bottom of <br />the topsoil horizon to the top of spoil material. Field descriptions are located in <br />Appendix IV and lab data is located in Appendix II. All subsoil in all sample pits <br />classify as suitable subsoil (Appendix III, Table-2). SEN-1-99 is a dryland grass/forb <br />site and SEN-2-99 is a shrubland site. Both sites are in their second year of growth. <br />The results follow: <br />Depth- The average depth to the start of subsoil is 10.7 inches (0.9 feet} <br />below the surtace. Depth to subsoil ranges 7 to 19 inches (.6 to 1.5 feet). <br />Sample site S2-01-3 occurs over bedrock at a depth of 24 inches indicating <br />that this site only had surface disturbance. <br />Textures- Textures are looms, clay looms and clays. Clay content averages <br />28 percent and ranges 15 to 44 percent, sand content averages 39 percent <br />• and ranges 18 to 44 percent. Silt content averages 33 percent and ranges 30 <br />to 36 percent. <br />Page 6 of 10 <br />11/09/01 <br />