FORT MCMURRAY, AB, Oct. 4, 2012 /CNW/ - The Cumulative Environmental
Management Association (CEMA) has approved and forwarded an End Pit Lakes Guidance Document to the Government of Alberta for its consideration. The living document
took several years to complete and provides a 100-year operational plan
for the design and creation of the 30 proposed End Pit Lakes in the
mineable Athabasca oilsands region.
CEMA defines an oilsands End Pit Lake (EPL) as:
"An engineered water body, located below grade in an oil sands
post-mining pit. It may contain oil sands by-product material and will
receive surface and groundwater from surrounding reclaimed and
undisturbed landscapes. EPLs will be permanent features in the final
reclaimed landscape, discharging water to the downstream environment.
If oilsands operators can successfully demonstrate the effectiveness of
EPLs as a reclamation tool, the new lakes could also serve as a
permanent alternative to the temporary tailings ponds that now store
by-products of the oilsands extraction process. The Guidance Document,
which was written and peer reviewed by an international team of
scientists and engineers, draws on the best available science to help
operators test the concept.
"CEMA doesn't support or oppose the creation of End Pit Lakes in the
closure plans of oilsands mine operators with leases in the Wood
Buffalo region. But this document is currently the only one available
to the planners and engineers responsible for reclaiming oilsands
leases," said CEMA Executive Director Glen Semenchuk. "The work by the
End Pit Lake Task Group and its consultants is world-class and
A multi-stakeholder, non-profit society CEMA is a key advisor to the
provincial and federal governments and is committed to respectful,
inclusive dialogue and collaboration. It makes recommendations to
government on the management of cumulative environmental effects of
regional development on air, land, water and biodiversity. CEMA has
produced similar guidance documents for wetlands, soils, revegetation,
and riparian areas.
To view the End Pit Lake Document or for more information visit www.cemaonline.ca.
No oilsands end pit lake (EPL) currently exists, but about 29 are
proposed within the mineable oilsands region. The document presents the
scientific and engineering expertise to guide all reclamation
activities associated with EPL design and construction. This is a
technical guidance document, one that provides the information, direction, and the advice
that the planners and engineers who will be responsible for turning
about 29 pits into functioning, healthy aquatic ecosystems will require
to carry out those activities.
The current objectives for EPLs in the Athabasca oilsands were
established by stakeholders in the region who agreed to participate in
the information-gathering process: government agencies, Aboriginal and
non-governmental organizations, and industry. It does not represent the
views of all potential stakeholders, as a comprehensive survey or
formal consultative process was beyond the project's mandate.
EPLs may or may not contain tailings associated with mining. In general,
two types of EPLs are anticipated for oilsands mine sites:
EPLs with tailings storage: In this scenario, soft tailings such as fluid fine tailings or
thickened tailings are capped with a layer of freshwater. Inputs to the
lake include surface runoff, precipitation, groundwater seepage, and
consolidation waters from tailings deposits. Tailings become denser
over time and release pore water to the water cap. Process-related
materials that may be placed in the mined-out pits includes tailings
deposits, tailings sand, lean oilsands, overburden, petroleum coke and
process-affected waters that remain at the end of mine operations.
EPLs without tailings storage: The excavated mined-out pit is allowed to fill with surface runoff and
groundwater once mining and dewatering activities cease. The list of
design and management considerations of EPLs that do not contain
tailings is significantly shorter than those that do store mine
Returning mineable oilsands developments in the Athabasca oilsands
region to a state functionally equivalent to the natural conditions
that characterize the boreal forest of northern Alberta will involve a
sophisticated suite of tools, techniques, and expertise. The end pit
lake is an integral element of this task.
Reclamation of the pit that remains at the end of a mine's life, and its
transformation into a sustainable lakes, is a developing technology. As
a result, industry can draw on experiences from pit lakes created in
other mining industries along with current research and literature
reviews conducted within the region. Such experiences include Syncrude
Canada's Base Mine Lake (BML) demonstration lake and test wetlands and
CEMA's in-lake dynamics and water quality modeling and geotechnical
stability analysis of EPL shorelines. The oilsands can also draw on
experience from pit lakes created by other industries, such as Teck
Coal's Sphinx Lake in Sparwood, British Columbia.
The permanent placement of fine tailings in EPLs is approved for many
oilsands mines, subject to demonstration, based on previous Energy and
Utilities Board Decisions.
EPLs will not be constructed in the undisturbed landscapes.
Independent experts reviewed every chapter of this document. But the
science of EPLs and the regulations that govern their construction and
management will continue to evolve. This document is intended to
provide a base of knowledge, and direction, for EPL design and
SOURCE: Cumulative Environmental Management Association
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