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Geotechnical News • March 2017
WASTE GEOTECHNICS
To perform this test, the sample was
simply tipped to pour out (or not)
and photographed. We found samples
would pour from the jar if they had
less than about 0.3 kPa peak strength.
Summary and conclusions
Indeed, unamended oil sands fluid fine
tailings has a consistency like choco-
late milk. Thickened tailings can be
compared to sour cream and various
sauces poured from a jar. Centrifuge
tailings are similar to mayonnaise
and ketchup. Flocculated tailings
and thickened tailings amended with
flyash are similar in consistency to
grape jelly, peanut butter, and jello.
Such foods are designed to be easy
to manufacture, easy to get out of the
bottle or container, easy to spread, and
easy to eat.
Fluids and fluid mechanics are poor
substitutes for soils and soil mechanics
for building tailings deposits, land-
forms, and landscapes that provide
bearing capacity, slope stability, and
acceptable consolidation settlements.
There is a need to introduce tailings
technologies that produce strengths
more like firm to stiff soils to make
tailings capping and reclamation reli-
able, safe, and economical.
Next steps
If you’ve got vane strengths of some
foods from your region or strengths
of soft tailings from your mine, please
let us know and we’ll add them to
our database for an upcoming journal
publication.
Recommended reading
CCA (Council of Canadian Acad-
emies). 2015. Technological
Prospects for Reducing the Envi-
ronmental Footprint of Canadian
Oil Sands. The Expert Panel on the
Potential for New and Emerging
Technologies to Reduce the Envi-
ronmental Impacts of Oil Sands
Development. Council of Cana-
dian Academies. Ottawa. 252p.
CTMC (Consortium of Oil Sands Tail-
ings Management Consultants).
2012. Oil Sands Tailings Technol-
ogy Deployment Roadmaps Proj-
ect Report. Consultant’s Report to
Alberta Innovates – Energy and
Environment Solutions and the Oil
Sands Tailings Consortium. June
29, 2012. Calgary. 4v
McKenna G, Mann V, Fisseha B,
Beier N, & Olmedo N. 2016a. The
geotechnical vane strength of soft
tailings compared to soft foods.
Fifth International Oil Sands Tail-
ings Conference, December 4-7.
Lake Louise, Alberta. University
of Alberta Geotechnical Group,
Edmonton.
McKenna G, Mooder B, Burton B, &
Jamieson A. 2016b. Shear strength
and density of oil sands fine tail-
ings for reclamation to a boreal
forest landscape. IOSTC Interna-
tional Oil Sands Tailings Confer-
ence. Lake Louise. Dec 4 to 7.
University of Alberta Geotechnical
Group. Edmonton.
Olmedo NA & Lipsett MG. 2016.
Design and field experimentation
of a robotic system for tail-
ings characterization. Journal of
Unmanned Vehicle Systems. 4:3
169-192.
Figure 5. Spoon test: A - condensed
milk (0.07 kPa fail); B - ketchup
(0.22 kPa pass vertical); C - peanut
butter (1.8 kPa pass horizontal).
Spoon will stand vertical if >0.2 kPa,
horizontal if >0.4 to 0.8 kPa.
Figure 6. Pour test. A - fluid fine tail-
ings (0.07kPa); B - chocolate milk
(0.05 kPa); C - yogurt (0.4 kPa).
Materials pour if <0.3 kPa.
