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<br />Assumptions, Variables: <br />Ore Processed, tons/day 80 Pulp Densit , % 30 <br /> <br />Bulk D Density, ton/cu. d. <br />1.5 Avg. Annual Precip, <br />in. <br />15.72 <br />Avg. Pan Eva p., inches 38 <br />Saturated Slimes Moisture Cont., % 19.92 <br />A freeboard reserve of 12 inches shall be maintained from the ponded process water elevation and the top of the <br />embankment crest elevation. In the event of a 100 year/24-hour storm, it can be expected that 3.8" of precipitation <br />will become captured and co-mingled with the ponded process water (run-off has been managed with a diversion <br />ditch network, see SWMP). This will raise the ponded water elevation. Having 12 inches of freeboard will more <br />than adequately provide for the necessary storage volume; preventing overflow and embankment erosion. <br />The Barrier Bench deposition (anticipated 4 month period) will allow a chance for a great deal of empirical testing <br />to verify these construction methods are adequate. The concrete leachate collection barrier provides for a solid <br />starter dyke and this initial upstream raised embankment can be tested for stability; it is backed up by the concrete <br />barrier. Spigotting variables can be refined. Deposited tailings can be core sampled to check densities and <br />saturation levels in both the coarse and slimes zones. This same testing program can be utilized throughout <br />operations. <br />Tailings Sampling Procedure for Bulk Density/Consolidation Check (to be performed prior to rising the next 10' <br />incremental embankment lift): <br />Construct multiple survey markers and place at 20' spacing on top of liner along area where newly <br />deposited tailings will reside. <br />o Marker shall consist of a nominally 24" square, 10 ga. steel plate with a 48" #5 rebar welded in the <br />center, upright at an angle that will be plumb when placed on grade. <br />o Over this rebar a piece of 1/4" diameter x 10' long PVC pipe shall be inserted. <br />o The PVC pipe shall be graduated in 2' increments to provide for depth measurement. <br />o As the impoundment rises, a new piece of PVC pipe can be installed for continuous measurement. <br />- Drill and push a 2" dia. thin walled Shelby Tube to appropriate depth immediately next to a previously <br />installed survey marker. <br />o Driller must exercise extreme caution NOT to penetrate the liner system. <br />o The steel plate on the bottom of the survey marker will also provide a degree of protection for the <br />liner when drilling with a Shelby tube. <br />- Driller must use caution when retrieving Shelby tube. Tails will be extremely sensitive to vibration and <br />rough handling. <br />- Seal ends of Shelby tube with paraffin wax or plastic wrap and transport or hand carry to lab. Exercise <br />extreme caution not to disturb samples. <br />- To determine bulk density: <br />o Cut approx. 3 inch long section of the Shelby tube using a band saw or other similar method. <br />o Weigh this 3 inch section with tails and any moisture. <br />o Extrude all of the tails into a pan and place in oven to determine moisture content via ASTM D <br />2216. <br />o Weigh the empty Shelby tube section and determine diameter and height. <br />o From this information bulk density, water content and void ratio can be determined to compare <br />with consolidation data. <br />- Record data in permanent log in Venture Resources' files. <br />This testing will determine if the spigotting method is adequately classifying tailings into desired zones. If it is <br />determined inadequate, Venture Resources will revise the design and operating procedures to incorporate cyclones <br />into the tailings discharge stream. This will allow for more predicable and more thoroughly classified placement of <br />• coarse fraction on the embankment face. Consolidation density and moisture content can be checked. If <br />Page 20 of 35