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Geotechnical News • December 2015
GEOTECHNICAL INSTRUMENTATION NEWS
management terms that apply, for
example, in resource development
when the long term environmental
hazards of development are being
considered. It is not possible to imag-
ine today all of the issues that might
manifest themselves say 10 or 100
years from now. Hence the concept of
Unknown unknowns.
The GIN introduction seemed to imply
that the concept originated with Rums-
feld at the
news briefing he gave on February 12,
2002. The subject at hand was the lack
of evidence linking the government
of
with the supply of
to terrorist groups.
In spite of my inability to remember
why I am in the kitchen, the synap-
sis of longer term memory fired on
reading the introduction. I remem-
bered the moment in 1979 when
Elio D’Appolonia used the words
Unknown knowns and Unknown
unknowns. The reason I remember
was I said to myself “Why didn’t I
think of that?” That is now 36 years
ago.
The occasion was the presentation by
Dr. Elio D’Appolonia at the Province
of British Columbia Royal Commis-
sion of Inquiry into Uranium Min-
ing (1). With respect to the design
and construction of uranium tailings
impoundments, Dr. D’Appolonia testi-
fied:
Site conditions always pose unknowns,
or uncertainties, which may become
known during construction or opera-
tion to the detriment of the facility
and possibly lead to damage of the
environment or endanger public
health and safety. The risk posed by
unknowns is somewhat dependent on
the nature of the unknown relative to
past experience. This has led me to
classify unknowns into one of the fol-
lowing two types: 1. known unknowns
(expected or foreseeable conditions),
which can be reasonably anticipated
but not quantified based on past expe-
rience as exemplified by case histo-
ries in Appendix A, and 2. Unknown
unknowns (unexpected or unforesee-
able conditions), which pose a poten-
tially greater risk simply because they
cannot be anticipated based on past
experience or investigation.
Known unknowns result from phe-
nomena which are recognized, but
poorly understood. On the other hand,
unknown unknowns are phenomena
which cannot be expected because
there has been no prior experience
or theoretical basis for expecting the
phenomena.[1]
The concept of different degrees of
unknowns is original to D’Appolonia I
believe. As the above testifies, the con-
cept certainly did not originate with
Rumsfeld. Rumsfeld’s presentation
was 23 years after Elio D’Appolonia
made his remarks.
The Royal Commission of Inquiry
into Uranium Mining was set up in
response to development work that
was being carried out for the proposed
Blizzard uranium mine near Kelowna,
BC. British Columbia has nearly two
hundred known mineral occurrences
of uranium. In spite of these mineral
riches, there had never been an operat-
ing uranium mine in the province.
I was one of a team of consulting engi-
neers working on the Blizzard site.
My particular responsibility was waste
disposal. Hence, I had an invested
interest in the workings of the Com-
mission, and in its eventual findings
and recommendations. I attended the
presentations to the Commission on
the disposal of uranium-laden waste
rock and tailings.
One of a small number of principal
presenters to the Commission was Elio
D’Appolonia who had considerable
experience in mine development in
the United States and other countries.
D’Appolonia was a consultant to regu-
latory bodies in the US, and he sat on
mine design and development review
boards. His presentation to the Com-
mission was on the long term storage
of uranium mine tailings.
The findings and recommendations of
the Commission were disheartening.
On February 27, 1980, the Govern-
ment of British Columbia ordered a
seven-year moratorium on uranium
exploration and mining. As recently as
March 12, 2009, the BC Government
issued a Cabinet order that stopped
any review of proposed uranium and
thorium exploration and development
in the province, thereby extending the
1980 moratorium to the present day.
Donald Shields, Retired
801 – 21 Dallas Road, Victoria, BC,
Canada V8V 4Z9
Tel. (250) 519-0604
Email:
[1] Statement of Evidence of E.
D’Appolonia, D’Appolonia Consult-
ing Engineers, Pittsburgh, Pennsyl-
vania. Proceedings of the British
Columbia Royal Commission of
Inquiry into Uranium Mining, Phase
V: Waste Disposal, ISBN 0-7718-
8198-3, Page 9.
Dr. Elio D’Appolonia in 2008.
