A geochemical evaluation of a monolayer cover with an elevated water table for the reclamation of the Doyon-Westwood tailings ponds, Canada

2020 ◽  
Vol 79 (2) ◽  
Author(s):  
Nicolas J. Rey ◽  
Isabelle Demers ◽  
Bruno Bussière ◽  
Mamert Mbonimpa ◽  
Mario Gagnon
Author(s):  
Elodie Lieber ◽  
Isabelle Demers ◽  
Thomas Pabst ◽  
Émilie Bresson

Several reclamation approaches were developed in the last decades to control acid mine drainage from tailings storage facilities, including the monolayer cover combined with an elevated water table. Its performance is dependent on water table elevation and tailings saturation, and is directly affected by climatic conditions, therefore climate change needs to be taken into account to design resilient reclamation systems. The objective of this research was to evaluate three approaches to simulate climate change and compare the impact on reclamation performance up to year 2100. Numerical simulations were calibrated using experimental field data and future weather conditions were established based on three climate change scenarios adapted for local conditions. Results showed that the projected impact of climate change varied depending on the approach used. Simpler and more conservative approaches indicated that reclamation would eventually fail following an increase of droughts during future summers. However, 80-year simulations showed that reclamation failures (evaluated as oxygen flux) could be limited to a few isolated summers and that a well-designed monolayer cover with elevated water table appeared to remain efficient in the long-term. Overall, the probability to exceed the oxygen flux target of 1 mol/m2/y did not exceed 2% for the simulated conditions.


2013 ◽  
Vol 375 (1-2) ◽  
pp. 149-158 ◽  
Author(s):  
Kenedy E. Epie ◽  
Seija Virtanen ◽  
Arja Santanen ◽  
Asko Simojoki ◽  
Frederick L. Stoddard

2010 ◽  
Vol 213 (1-4) ◽  
pp. 437-458 ◽  
Author(s):  
Mariam Ouangrawa ◽  
Michel Aubertin ◽  
John W. Molson ◽  
Bruno Bussière ◽  
Gérald J. Zagury

2016 ◽  
Author(s):  
Nicolas J. Rey ◽  
Isabelle Demers ◽  
Bruno Bussière ◽  
Mamert Mbonimpa ◽  
Sylvain Lortie

2020 ◽  
Vol 57 (12) ◽  
pp. 1998-2009
Author(s):  
Nicolas J. Rey ◽  
Isabelle Demers ◽  
Bruno Bussière ◽  
Mamert Mbonimpa

The use of monolayer covers combined with an elevated water table (EWT) is a promising reclamation method that relies on the low gas-diffusivity of water to limit oxygen ingress into potentially acid-generating tailings. A monolayer cover is installed over the sulfidic material and the water table level is controlled to maintain the tailings close to saturation. A protocol including laboratory columns was conducted to evaluate the sensitivity of the technique to parameters including cover thickness, water table level, and the presence of an anti-evaporation layer. Two types of desulfurized tailings were evaluated: silty tailings from Westwood mine and sandy tailings from Goldex mine. Data used to evaluate the covers performances included volumetric water content, suction, oxygen concentrations, and oxygen consumption. Results showed that both cover materials could be used to maintain the reactive tailings at a degree of saturation ≥90% when the EWT level was maintained at a maximum distance of 1 m below the tailings surface. The finer Westwood material showed a better capacity for limiting oxygen migration through the cover, with a maximum flux of 5.7 mol·m−2·year−1 measured near the cover base.


2010 ◽  
Vol 14 (11) ◽  
pp. 2207-2217 ◽  
Author(s):  
T. Y. Tebebu ◽  
A. Z. Abiy ◽  
A. D. Zegeye ◽  
H. E. Dahlke ◽  
Z. M. Easton ◽  
...  

Abstract. Gully formation in the Ethiopian Highlands has been identified as a major source of sediment in water bodies, and results in sever land degradation. Loss of soil from gully erosion reduces agricultural productivity and grazing land availability, and is one of the major causes of reservoir siltation in the Nile Basin. This study was conducted in the 523 ha Debre-Mawi watershed south of Bahir Dar, Ethiopia, where gullies are actively forming in the landscape. Historic gully development in a section of the Debre-Mawi watershed was estimated with semi structured farmer interviews, remotely sensed imagery, and measurements of current gully volumes. Gully formation was assessed by instrumenting the gully and surrounding area to measure water table levels and soil physical properties. Gully formation began in the late 1980's following the removal of indigenous vegetation, leading to an increase in surface and subsurface runoff from the hillsides. A comparison of the gully area, estimated from a 0.58 m resolution QuickBird image, with the current gully area mapped with a GPS, indicated that the total eroded area of the gully increased from 0.65 ha in 2005 to 1.0 ha in 2007 and 1.43 ha in 2008. The gully erosion rate, calculated from cross-sectional transect measurements, between 2007 and 2008 was 530 t ha−1 yr−1 in the 17.4 ha area contributing to the gully, equivalent to over 4 cm soil loss over the contributing area. As a comparison, we also measured rill and interrill erosion rates in a nearby section of the watershed, gully erosion rates were approximately 20 times the measured rill and interrill rates. Depths to the water table measured with piezometers showed that in the actively eroding sections of the gully the water table was above the gully bottom and, in stable gully sections the water table was below the gully bottom during the rainy season. The elevated water table appears to facilitate the slumping of gully walls, which causes the gully to widen and to migrate up the hillside.


2010 ◽  
Vol 7 (4) ◽  
pp. 5235-5265 ◽  
Author(s):  
T. Y. Tebebu ◽  
A. Z. Abiy ◽  
H. E. Dahlke ◽  
Z. M. Easton ◽  
A. D. Zegeye ◽  
...  

Abstract. Gully formation in the Ethiopian Highlands has been identified as a major source of sediment in water bodies, and results in sever land degradation. Loss of soil from gully erosion lowers crop yields, reduces grazing land availability, and is one of the major causes of reservoir siltation in the Nile Basin. This study was conducted in the 523 ha of Debre-Mawi watershed south of Bahir Dar, Ethiopia, where gullies are actively forming in the landscape. Historic gully development in a section of the Debre-Mawi watershed was estimated with semi structured farmer interviews, remotely sensed imagery, and estimates of current gully volumes. Gully formation was assessed by instrumenting the gully and surrounding area to measure water table levels and soil physical properties. Gully formation began in the 1980's following the removal of indigenous vegetation, leading to an increase in surface and subsurface runoff from the hillsides. A comparison of the gully area, estimated from a 0.58 m resolution quick bird image, with the current gully area mapped with a GPS, indicated that the total eroded area of the gully increased from 0.65 ha in 2005 to 1.0 ha in 2007 and 1.43 ha in 2008. The gully erosion rate between 2007 and 2008 was 530 t ha-1yr-1 in the 17.4 ha area contributing to the gully, equivalent to over 4 cm soil loss over the contributing area. As a comparison, we also measured rill and inter-rill erosion rates in a nearby section of the watershed, gully erosion rates were approximately 20 times the measured rill and inter rill rates. Depths to the water table measured with piezometers showed that in the actively eroding sections of the gully the water table was above the gully bottom and, in stable gully sections the water table was below the gully bottom during the rainy season. The elevated water table facilitates the slumping of gully walls, which causes widening and up-migration on the hillside.


2018 ◽  
Vol 55 (12) ◽  
pp. 1742-1755 ◽  
Author(s):  
Marie-Pier Ethier ◽  
Bruno Bussière ◽  
Michel Aubertin ◽  
Abdelkabir Maqsoud ◽  
Isabelle Demers ◽  
...  

The abandoned Manitou mine site produced acid mine drainage for decades. One of the site’s tailings storage facilities (TSF 2) was reclaimed in 2009 using an elevated water table combined with a monolayer cover made of low-sulphur tailings. A field investigation was undertaken from 2012 to 2015 to verify the performance of the reclamation technique in stemming the production of contaminants. This verification is based on two main criteria, i.e., the minimum water table level and maximum oxygen flux reaching the Manitou tailings. Thirteen monitoring stations were installed in TSF 2. The hydrogeological behavior and oxygen migration were investigated at each station by measuring volumetric water content, suction, water table level, gaseous pore oxygen concentration, and oxygen consumption. Analyses of field data showed that the minimum water table level criterion was reached with the exception of a portion of TSF 2 during the summer months. Oxygen fluxes reaching the Manitou tailings were determined using numerical simulations and analytical solutions; their yearly mean was many times lower than maximum targets generally used on reclaimed tailings disposal areas. The current system met the targeted performance criteria over the studied period.


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