Laserfiche WebLink
Design Report <br /> Daniels Sand Wash Fines Pit <br /> 9/21/2016 <br /> Page 3 of 5 <br /> encountered at 33.5 feet and extended below exploration. The blow counts ranged from 26 bpf <br /> to 50 blows per 2 inches (50/2"). <br /> 3.4 Groundwater <br /> Groundwater was encountered in every boring during drilling as shown in the figure below. <br /> Fluctuations in the groundwater level may occur due to variations in rainfall, temperature, site <br /> development, and other factors not evident at the time that these measurements were made. <br /> Table 3-3. Groundwater Readings <br /> Boring Groundwater Readings feet below ground surface <br /> BA-1 7.5 <br /> BA-2 19 <br /> BA-3 20 <br /> BA-4 18 <br /> 3.5 Borrow Source Material <br /> Brierley collected three samples from the stockpile location as indicated by Transit Mix. The <br /> stockpile had a maximum dry density of 115.6 pcf and optimum moisture content of 11.2 <br /> percent. Three Atterberg limits were conducted on the stockpile samples with liquid limits <br /> ranging from no value to 23 and plasticity index ranging from non-plastic to 5. The fines content <br /> of the stockpile ranged from 14 to 26 percent. However, the eolian deposits remaining within <br /> the footprint of the new impoundment pond exhibit better engineering properties for use as <br /> embankment materials when compared to the stockpile results. Utilizing the eolian deposits <br /> within the pond footprint will also increase the storage volume. <br /> 4 DESIGN RECOMMENDATIONS <br /> The embankment shall have a design top width of 15 feet. The final slopes shall have a <br /> maximum slope of 2.5H:1 V. The grading plan is provided on Figure 3 and a typical section is <br /> depicted on Figure 4. <br /> After removal of any vegetation and debris on the face of the existing mine highwalls which will <br /> form the abutments of the embankment, all new fills should be benched into place by cutting <br /> steps into the existing slope. The maximum horizontal and vertical dimensions of the steps are <br /> typically 6 ft and 2 ft respectively, as shown on Figure 5. <br /> Brierley recommends that borrow for the embankment construction is obtained from the existing <br /> mine floor within the footprint of the new impoundment pond. The borrow material should <br /> consists of the eolian soils with USCS classifications of SM, SC, or CL. The coarse alluvium <br /> that was encountered beneath the eolian deposits at an appropriate depth of 30 feet should not <br /> be used as borrow. <br /> 5 CONSTRUCTION PROCEDURES AND RECOMMENDATIONS <br /> Earthwork specifications are provided in Appendix C. If necessary, the site should be <br /> revegetated in accordance with the current mining permit. Additional site grading and earthwork <br /> recommendations are provided below. <br /> BRIERLEY <br /> ASSOCIATES <br /> Creating Space Underground <br />