• Based on the worst case Coarse Fraction Friction Angle of (PCFA= 370, the proposed maximum free-faced slope of
<br />the tailings impoundment of 1.5h : 1 v (9,j,,pe 33.70) will be satisfactory and stable over the long term; providing a
<br />factor of safety, FS = tan 1QCFA/tan cpslope 1.13. Remember, compounding factors of safety and conservative
<br />assumptions have led us to this point. Using this CU analysis, a 1.5 factor of safety in determining the maximum
<br />confining pressure of 15,000 lb/ft2, considering the relatively slow rate of tailings deposition, and assuming
<br />saturated conditions; Venture Resources is confident the analysis provides for a very conservative result.
<br />•
<br />•
<br />The Slimes Fraction is constrained and confined by the Coarse Fraction at the free face (see cross-section drawing
<br />Exhibit El 1). A unique geometry presents itself as the tails are impounded. As the tailings volume fills and
<br />Coarse/Slimes segregation occurs in an approximate proportion of 1.0 Coarse : 1.9 Slimes, the Impounded Slimes
<br />Fraction Angle builds at an average of 2.1h : Iv (9impounded slimes 25.40). The worst case Slimes Fraction Friction
<br />Angle is (PSFA= 31.90. This arrangement will be satisfactory and stable over the long term; providing a factor of
<br />safety, FS = tan cpsFA/tan 9impounded slimes = 1.31 ... completely discounting the added stability of the Coarse Fraction
<br />constraint.
<br />The capacity and rate of fill for the Tailings Impoundment has been summarized:
<br />Tahip 7.
<br />Tailings Impoundment
<br />Capacity
<br /> Totals Operating Duration @
<br />80 ton/day (months) Total
<br />Bench
<br />i Zone (10'
<br />step lifts Cu. Yds. Tonnage* Cu. Yds. Tonnage Months
<br />Barrier Top of Dam 6,078 9,117 6,078 9,117 3.8 3.8
<br />Bench 1 Step 1 10,081 15,122 6.3
<br /> Step 2 12,893 19,339 8.1
<br /> Step 3 18,713 28,069 11.7
<br /> Step 4 17,444 26,167 59,131 88,697 10.9 37.0
<br />Bench 2 Step 5 16,674 25,011 10.4
<br /> Step 6 18,967 28,450 11.9
<br /> Step 7 20,965 31,447 13.1
<br /> Step 8 23,074 34,611 79,680 119,519 14.4 49.8
<br />Bench 3 Step 9 21,861 32,792 13.7
<br /> Step 10 23,370 35,056 14.6
<br /> Step 11 25,263 37,894 15.8
<br /> Step 12 27,296 40,944 97,791 146,686 17.1 61.1
<br />Bench 4 Step 13 26,167 39,250 16.4
<br /> Step 14 28,824 43,236 18.0
<br /> Step 15 30,726 46,089 19.2
<br /> Step 16 33,185 49,778 118,902 178,353 20.7 74.3
<br />Bench 5 Step 17 31,156 46,733 19.5
<br /> Step 18 32,830 49,244 20.5
<br /> Step 19 33,133 49,700 97,119 145,678 20.7 60.7
<br />
<br /> Totals 468,700 688,050 286.7
<br /> (months)
<br />* Tonnage figured at 1.5 ton/cu. yd. 23.9
<br /> (years)
<br />Page 25 of 35
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