Grants and Contributions:

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Title:

Assessing the feasibility of using lime to mitigate chemical flux in oil sands end pit lakes

Agreement Number:

EGP

Agreement Value:

$25,000.00

Agreement Date:

Sep 20, 2017 -

Organization:

Natural Sciences and Engineering Research Council of Canada

Location:

Alberta, CA

Reference Number:

GC-2017-Q2-04324

Agreement Type:

Grant

Report Type:

Grants and Contributions

Additional Information:

Grant or Award spanning more than one fiscal year (2017-2018 to 2018-2019).

Recipient's Legal Name:

Ulrich, Ania (University of Alberta)

Program:

Engage Grants for Universities

Program Purpose:

In northeastern Alberta, large volumes of fluid fine tailings (FFT) are produced during bitumen extraction fromx000D
surface-mined oil sands ore. FFT is comprised of water, fine clays, naphthenic acids (NAs), residual bitumenx000D
and other unrecovered hydrocarbons. FFT takes decades to dewater in tailings ponds. Hence, the growingx000D
inventory compels operators to seek alternative tailings management strategies. End pit lakes (EPLs) with FFTx000D
below a water cap in mined out pits are one of the potential options. The expectation is that EPLs will slowlyx000D
develop into self-sustaining aquatic ecosystems. Potential issues with EPLs may include movement ofx000D
constituents of potential concern (COPCs) from the FFT into the overlying cap water contributing to on-goingx000D
sources of possible toxicity. Thus, research has been undertaken to resolve these issues and determine thex000D
feasibility of EPLs as a reclamation strategy.x000D
Graymont Western Canada Inc. is an emerging global leader in the supply of lime and limestone products.x000D
Graymont has conducted preliminary tests showing that 1) lime addition to FFT in the range of 750 to 1500x000D
mg-CaO/kg-FFT improves FFT dewatering and facilitates the release of residual bitumen, and 2) lime additionx000D
to oil sands process-affected water (OSPW) induces calcium naphthenate precipitate formation at pH 12. Thesex000D
preliminary findings can be leveraged by further investigating how lime treatment can mitigate COPC fluxx000D
across the FFT-water cap interface in EPLs. Both of these issues are of relevance for the timely development ofx000D
EPLs in the oil sands industry.x000D
In this study, lime will be tested for its ability to enhance FFT dewatering and NA removal in lab-scale batchx000D
experiments representative of an EPL. The purpose of this study to assess the feasibility of using lime as ax000D
pre-treatment step in EPLs for efficient and economical oil sands tailings reclamation.