| Bre-X's
salted boreholes
Line No. 44 and 49 in South-East Zone
Test
for spatial dependence
The
calculated value of F=0.937/0.672=1.39 for SEZ44 does
not exceed the tabulated value of F0.05;dfo;dfr=F0.05;16;8=2.98
at 5% probability. Hence, the variance of the randomized
set and the first variance term of the ordered set are
statistically identical, and the ordered set of bogus
borehole grades in SEZ44 does not display a significant
degree of spatial dependence. Similarly, F=2.080/1.558=1.34
for SEZ49 is less than F0.05;20;10=2.77 so that the ordered
set of salting-enhanced borehole grades in SEZ49 does
not exhibit spatial dependence either. Clearly, Bre-X's
salting squad didn't know how to create any delusion of
spatial dependence between boreholes.
I
obtained these test results long after Bre-X's Busang
gold resource turned out to be a salting scam. However,
Bre-X's management and its consultants, too, could have
found out that widely spaced lines such as SEZ44 and SEZ49
did not display spatial dependence between boreholes within
lines. So who is to blame that this simple F-test is not
applied in mineral exploration? Is it the Journelian presumption
of spatial dependence without proof? Is it Armstrong's
penchant for perfect smoothing? Or are mining professionals
hooked on the kriging game? |
