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| Dr
Isobel Clark derived the variance of a distance-weighted
average but didn't test for spatial dependence between
measured values in her ordered set.
Dr Roussos Dimitrakopoulos, McGill's
miracle man and JMG's Editor-in-Chief,
knows all about stochastic mine planning optimization
with kriging variances. He has yet to apply it to
Bre-X's phantom gold resource to find out what mining
plan pops up with voodoo variances.
What
kept Bre-X humming along was to assume gold mineralization
between salted boreholes, to krige and smooth a
little, and to rig the rules of statistics a lot.
The National Securities Regulator ought
to rule that unbiased confidence limits for contained
metal be reported.
Matheron, the self-made wizard
of odd statistics, lost the variance of the length-weighted
grade in 1954. He didn't test for spatial dependence.
Nor did he take to counting degrees of freedom. |
Photo
by Nick Didlick
Jan
W Merks
metrologist,
author, lecturer, consultant, whistleblower,
'gadfly', 'pariah', 'iconoclast',
CIM Life Member |
|
Dr
F P Agterberg
stripped the variance off his distance-weighted average
point grade in his 1970 paper and once more in his 1974
Geomathematics. He mentioned degrees of freedom
and Fisher's F-test in this textbook. Why didn't he show
how to test for spatial dependence between core samples
in a borehole, or between boreholes on a line? He ought
to delete Chapter 10 Stationary Random Variables and
Kriging. Surely, a distance-weighted average grade
without a variance is a genuine scientific fraud!
In November 1989, we applied
Fisher's F-test in Precision
Estimates for Ore Reserves
to confirm spatial dependence between gold grades of ordered
rounds in a decline. Testing for spatial dependence troubled
Professor
Dr M David, CIM
Bulletin's most dedicated enforcer of Matheronian geostatistics.
Scores of similarly gifted geostatistocrats postulated
spatial dependence may be inferred unless proven otherwise.
All sorts of degrees of freedom fighters were troubled
when "classical
Fischerian [sic] statistics" proved
spatial dependence between gold grades of ordered rounds.
Fisher's F-test also proved the intrinsic variance of
Bre-X's bogus gold in Busang's barren rock to be statistically
identical to zero, as it ought to be. Sound statistics
did so several months before Bre-X's boss salter vanished!
Bre-X's original and duplicate bogus assays for a few
early boreholes could have proved early on that a salting
scam was in progress at the Busang project!
Dr F P Agterberg, Past President,
International Association for Mathematical Geosciences,
does not talk but others do speak on his behalf. Professor
Dr R Dimitrakopoulos, Editor-in-Chief, Journal for
Mathematical Geosciences, stand on guard against
genuine variances. This association and its journal got
new names but the kriged game remains the same. Why should
Agterberg revise his 1974 Geomathematics? After
all, mining investors accept mineral inventories in annual
reports without demanding confidence limits.
Dimitrakopoulos is the Canada
Research Chair and BHP Billiton Chair in Mine
Planning Optimization at the Department of Mining,
Metals and Materials Engineering at McGill University.
He teaches McGill's students all he knows about stochastic
modeling with voodoo variances. When he chaired in June
1993 a forum on Geostatistics for the Next Century,
he did not know that each and every kriged estimate does
have its own variance. JMG's Editor-in-Chief is still
playing games with pseudo kriging variances. Surely, McGill's
students should be smart enough to derive the variance
of any weighted average. They should know that stochastic
modeling with voodoo variances is a scientific fraud.
Of course, geoscientists ought to know why stochastic
modeling with voodoo variances gives junk statistics.
The world's mining industry
is caught in a Catch-22. The problem
is that metal grades and contents of mineral inventories
in annual reports are bound to shrink during mining. David
dabbled at geostatistical
grade control in his 1988 handbook. He was
proud that his kriged
block was larger than
his so-called erratic
block. What he did not
show is that his kriged block has a significantly lower
grade. Less pay dirt in mined ores and more tailings in
ponds! Geostatistical grade control in exploration and
mining but statistical grade and quality control with
ISO standards in smelting and refining!
It's a a Catch-22! Apply sound statistics in smelting
and refining and work with goofy geostatistics in mineral
exploration and mining!
The National Securities Regulator ought to rule
it a scientific fraud to assume ore between boreholes.
Bre-X showed more red flags than a Bolshevist parade.
The OSC watched the parade with Felderhof in front! Incompetence
runs rampant but is not deemed a crime. I explained to
the OSC
in 1994 and to the SEC
in 2003 why Matheronian geostatistics is a flawed variant
of applied statistics. Infinite sets of kriged estimates,
zero pseudo kriging variances and no degrees of freedom
make goofy statistics! But it seems to make sense to CRIRSCO's
new Chair and her flock of Crirsconians!
Matheron's quixotic work
is posted with the On-Line
Library of the Centre de Géostatistique.
Matheron was not a born genius at probability but a self-made
wizard of odd statistics. One-to-one correspondence between
variances and functions remained beyond his grasp until
his passing in 2000. Matheron fumbled two variances whereas
Agterberg fumbled the same variance twice. Scores of somehow
qualified persons accept voodoo statistics as
much as do born geostatistocrats and krigeologists!
Teck's Patricia Dillon and
her team of statistically challenged experts talk confidently
about confidence without limits. Applied statistics does
give unbiased confidence limits for metal contents of
mined ores and mineral concentrates. It does so not only
for metal contents and grades of ore reserves but also
for proven ore within inferred resources. Borehole
Statistics with Spreadsheet
Software shows how to derive 95% confidence
intervals and ranges for masses of metals in volumes of
in-situ ores. It's high time to set up an ISO
Technical Committee on reserve and resource estimation.
But Barrick Gold, BHP Billiton, Rio Tinto and a few others
prefer the geostatus quo.
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