Prediction of Occurrence of Discrete Events - Geomathematics: Theoretical Foundations, Applications and Future Developments - page 151

Table 5.2 Calculation of optimal cut-off of gold in balsam fir, to maximize the contract C with known gold occurrence points
Cut off Cumulative

Area km 2 W + (W + ) W (W ) %ile ppb Occurrences# C (C) C/ (C)

σ σ σ σ

98 137 42 0 - - - - - - -

0.0133

95 24 93 3 0.3438 0.58690 0.1254 0.3571 0.6002 0.2090

0.1349

90 16 227 13 0.9439 0.2856 0.1362 1.0788 0.3164 3.4095

80 12 435 24 0.9045 0.2100 0.2812 0.1521 1.1856 0.2593 4.5724

70 10 848 31 0.4733 0.1830 0.2745 0.1659 0.7479 0.2470 3.0279

60 8 1,070 35 0.3582 0.1719 0.2771 0.1756 0.6353 0.2457 2.5853

50 7 1,360 45 0.3701 0.1516 0.4732 0.2100 0.8433 0.2590 3.2560

< 50 3-6 2,591 64 0.0695 0.1266 0.7295 0.5028 0.7900 0.5185 1.5237

Outside 2,945 68 - - - - - - -

Source: Bonham-Carter et al. ( 1990 , Table 2)