Shaft/hole

No of intervals

T1 nb/%

T2

T3

T4

T4

S T4 + T5

IBO-1N

429

95/22.14

77/17.95

154/35.90

35/8.16

68/15.85

24.01%

IBO-2

524

162/30.92

86/16.41

127/24.24

149/28.43

-

28.43%

IBO-3

325

80/24.61

165/50.77

48/14.77

32/9.85

-

9.85%

IBO-4

464

108/23.29

172/37.07

131/28.23

153/3.23

38/8.19

11.42%