Oil Sand Reclamation
Revision: November 2006
Author: Jack Caldwell
InfoMine has posted twelve technical papers by Les Sawatsky and his many coauthors in the InfoMine Library. You can access them through the Library using the author’s name as a keyword or via the author search.
Because of the technical significance of these papers both to reclamation of Oil Sands mines and the greater mining industry, we summarize and survey the papers in this review. The primary focus of the papers and hence of this review is the application of the principles of geomorphology to mined land reclamation.
way of background, I admit to great sympathy with the geomorphic approach to
design of mined land reclamation works.
Recently I visited three uranium mill tailings piles in
ideas and approaches did not gain currency outside the uranium tailings
remediation arena because of concern for the costs of the works we designed and
constructed. And this is understandable. But the tide seems to have changed: now we
The basic plea and principles are set out by Sawatsky et al. in the paper Integrated Mine Water Planning and for Environmental Protection and Profitability. In this paper the authors plead for multidisciplinary input, acceptance of environmental and economic goals, partnership amongst planners, designers, operators, and regulators, acceptance of water issues being equal to mining concerns, innovative solutions at an early stage of mine planning, a sound understanding of natural analogues, data collection and monitoring, inventory of baseline fluvial and geomorphic conditions, early establishment of design criteria, and planning by iteration.
These ideas are further explored in the paper by Sawatsky and Beakstead Geomorphic Approach for Design of Sustainable Drainage Systems for Mineland Reclamation. Here the authors point out that uniform landscapes are immature and that rivers meander, balance develops between erosion and sedimentation, and that flood plains attenuate flows. The authors call for application of these obvious geomorphic facts in the design of mined land reclamation works.
In their paper, Mine Planning Guidelines for Developing Sustainable Drainage Systems, Sawatsky et al. posit these guidelines:
· To the extent reasonable, pre-development surface flows to receiving waters should be restored; for example they recommend that the ten-year flow to receiving waters should not exceed the pre-development flow by more than thirty percent.
· Avoid side-hill diversions that may be blocked by ice, beaver dams, or sediment.
· End-of-mine lakes should be at the end of flow paths.
· Liquid impoundments, including final tailings ponds, should be below grade.
· Final grades should be less than pre-development grades to account for the greater erodabilty of the reclamation soils.
· Major drainage courses should be on undisturbed ground at low gradients that limit erosion.
The principles are applied as described in the paper Natural Analogs For Sustainable Landscape Design at Syncrude, Keys et al. establish these criteria:
They expand on the application of these principles in practice, including providing information on the geomorphic processes and rates operative in the area of the mine, the design of mine lakes, accommodation of beaver dams, placement of rip-rap to control stream erosion, aeolian erosion of tailing piles 60 m above the natural landscape, and post-mining maintenance and monitoring.
of the application of the principles discussed above to a coal mine in the
· Robust, self-healing capacity provided by several lines of defense against sustained erosion.
· Ready supply of armoring material where erosion has occurred.
· Adjustment of channel size and shape to handle peak flows.
· Gradual evolution.
· Sediment balance.
· A stable configuration that is not vulnerable to rapid change.
In an eloquent plea for the adoption of rational sediment yield criteria to mine land reclamation, in the paper A Strategy for Determining Acceptable Sediment Yield for Reclaimed Mine Lands, Bender et al. set out these criteria for a sustainable landscape:
On the basis of a detailed examination of the factors that affect the health of receiving waters, the authors conclude that the following guidelines should be used to establish acceptable sediment yields:
are the main source of eroded soil from a mine or any slope that is steeper
than the natural surrounding topography.
We have all seen the severely gullied slopes on many a mine waste
disposal facility. I have walked the
1,000-year old gullies of the Cahokia Mounds in
In many ways these earlier papers by Sawatsky and coauthors are but a run up to the 2004 paper where their developed and more mature ideas are set out. I cannot quote all I would like to from the papers by Sawatsky [alone this time] entitled Reclamation Strategies that Address Mine Closure Drainage. But if you choose to read only one paper, this is the paper I recommend. Here are some quotes that caught my attention:
This paper is full of many checklist, practical design advice, case history wisdom, and reality-base advice. I recommend it if your business in mined land reclamation.
Here are the other four papers by Sawatsky that I do not review—not because they are not good (if you can follow the multiple negatives) but because they are not apposite to the topic of this piece. Nevertheless, I recommend you access them and read them: