Devonian Potash Deposits in Manitoba - Government of Manitoba

Assumptions used in the reserve calculations are listed below:1. Grade variations between test holes are linear2. Optimum mining height including dilution is 8.0 feet (2.44 metres)3. Specific gravity of the potash unit is 2.04. "Dummy" test holes having an assumed grade of zero per cent K20 in sylvite arepositioned two miles (3.2 kilometres) distant from peripheral test holescontaining values above a cutoff grade of 16.0 per cent K20 in sylvite.Assumptions used in calculating the life of the different reserve estimates are:1. Production rate of 1.8 million tonnes of product per annum grading 61 per centK20 (2.0 million short tons)2. Extraction of 35 per cent of the calculated reserve3. 87 per cent mill recoveryStratigraphic 8.0 Feet (2.44 Metres)TABLE 1RESERVE AND LIFE ESTIMATES-Cutoff Grade (% K 0 in Sylvite)216% 1 ax 20%Life (years)Cutoff gradeAreaTonnesx lo6% K20Tonnesx 10 6% K20Tonnesx lo6% K20167' 18% 20%South480 21.5390 22.5290 23.828 2 4 19North170 19.5120 20.570 21.79 7 4Total650 20.95 10 22.0360 23.43 7 31 23Best 8.0 Feet (2.44 Metres)Cutoff Grade (% K 0 in Sylvite)216% 1 ax 20%Life (years)Cutoff gradeAreaTonnesx 10 6% K20Tonnesx 10 6% K20Tonnesx 10 6% K2016% 1 8% 2 04'South5 60 21.6450 22.7360 23.633 2 8 23North190 19.2120 20.570 21.610 7 4Total750 21 .O5 70 22.2430 23.34 3 3 5 2 7A comparison of the two reserve estimates, "stratigraphic" 8.0 feet (2.44 metres)versus "best1* 8.0 feet (2.44 metres), shows that the grades are nearly identical but the tonnageof the "bestv* 8.0 feet (2.44 metres) is somewhat higher than that of the "stratigraphic" 8.0