Laboratory study of low-sulfide tailings covers with elevated water table to prevent acid mine drainage

2020 ◽  
Vol 57 (12) ◽  
pp. 1998-2009
Author(s):  
Nicolas J. Rey ◽  
Isabelle Demers ◽  
Bruno Bussière ◽  
Mamert Mbonimpa
Keyword(s):  
Water Table ◽  
Mine Drainage ◽  
Degree Of Saturation ◽  
Water Table Level ◽  
Elevated Water Table ◽  
Oxygen Migration ◽  
Elevated Water ◽  
Oxygen Ingress ◽  
Sulfide Tailings ◽  
Cover Thickness

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.

Preventing Acid Mine Drainage with an Elevated Water Table: Long-Term Column Experiments and Parameter Analysis

2010 ◽  
Vol 213 (1-4) ◽  
pp. 437-458 ◽  
Author(s):  
Mariam Ouangrawa ◽  
Michel Aubertin ◽  
John W. Molson ◽  
Bruno Bussière ◽  
Gérald J. Zagury
Keyword(s):  
Acid Mine Drainage ◽  
Water Table ◽  
Mine Drainage ◽  
Parameter Analysis ◽  
Column Experiments ◽  
Acid Mine ◽  
Elevated Water Table ◽  
Elevated Water

In situ evaluation of performance of reclamation measures implemented on abandoned reactive tailings disposal site

2018 ◽  
Vol 55 (12) ◽  
pp. 1742-1755 ◽  
Author(s):  
Marie-Pier Ethier ◽  
Bruno Bussière ◽  
Michel Aubertin ◽  
Abdelkabir Maqsoud ◽  
Isabelle Demers ◽  
...  
Keyword(s):  
Water Table ◽  
Mine Drainage ◽  
Current System ◽  
Field Investigation ◽  
Performance Criteria ◽  
Disposal Site ◽  
Tailings Disposal ◽  
Water Table Level ◽  
Evaluation Of Performance ◽  
Elevated Water

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.

Oxygen diffusion and consumption in low-sulphide tailings covers

2009 ◽  
Vol 46 (4) ◽  
pp. 454-469 ◽  
Author(s):  
Isabelle Demers ◽  
Bruno Bussière ◽  
Mamert Mbonimpa ◽  
Mostafa Benzaazoua
Keyword(s):  
Water Table ◽  
Oxygen Diffusion ◽  
Mine Drainage ◽  
Effective Diffusion ◽  
Single Layer ◽  
Attractive Alternative ◽  
Sulphide Tailings ◽  
Elevated Water ◽  
Acid Mine Drainage Generation ◽  
Cover Thickness

Acid-generating tailings can be reclaimed using oxygen barrier covers in humid climates, such as in Quebec. A single-layer low-sulphide tailings cover is an attractive alternative to traditional water covers to maximize the impoundment’s storage capacity. Low-sulphide tailings can serve as a moisture-retaining material to limit oxygen diffusion, and their residual sulphides can consume the diffusive oxygen that still gets through the cover. A laboratory experiment using instrumented columns was initiated to confirm the efficiency of a low-sulphide tailings monolayer cover placed over acid-generating tailings to reduce the oxygen flux reaching the reactive tailings. Oxygen concentration profiles were measured over the thickness of the cover and oxygen fluxes were calculated to evaluate the effect of three parameters on these fluxes: water table level, cover sulphide content, and cover thickness. Oxygen fluxes at the bottom of the low-sulphide tailings cover layer, calculated using oxygen gradient and estimated effective diffusion coefficient and predicted using Vadose/W, were lower than 1.5 mol·m−2·year−1. These results suggest that a low-sulphide tailings cover with an elevated water table can reduce oxygen migration and potentially limit acid mine drainage generation.

Simulating the effect of climate change on the performance of a monolayer cover combined with an elevated water table placed on acid generating mine tailings

2021 ◽  
Author(s):  
Elodie Lieber ◽  
Isabelle Demers ◽  
Thomas Pabst ◽  
Émilie Bresson
Keyword(s):  
Climate Change ◽  
Water Table ◽  
Mine Drainage ◽  
Oxygen Flux ◽  
Climate Change Scenarios ◽  
Local Conditions ◽  
Elevated Water Table ◽  
Elevated Water ◽  
The Impact ◽  
Monolayer Cover

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.

The effects of a permanently elevated water table in an acid sulphate soil on reed canary grass for combustion

2013 ◽  
Vol 375 (1-2) ◽  
pp. 149-158 ◽  
Author(s):  
Kenedy E. Epie ◽  
Seija Virtanen ◽  
Arja Santanen ◽  
Asko Simojoki ◽  
Frederick L. Stoddard
Keyword(s):  
Water Table ◽  
Reed Canary Grass ◽  
Acid Sulphate Soil ◽  
Acid Sulphate ◽  
Elevated Water Table ◽  
Canary Grass ◽  
Elevated Water

scholarly journals Behaviour of Unsaturated Subgrade Soil Under Highway Load

2019 ◽  
Vol 12 (1) ◽  
pp. 23-33
Author(s):  
Ghassan Nasser Jaffer
Keyword(s):  
Water Table ◽  
Pore Water Pressure ◽  
Layer Structure ◽  
Water Pressure ◽  
Degree Of Saturation ◽  
Fe Model ◽  
Center Line ◽  
Water Table Level ◽  
Subgrade Soil ◽  
Dynamic Loadings

This paper studied the application of 2-D Plaxis (v8.6, 2011) software on a pavement layer structure set on unsaturated subgrade soil. An axisymmetric finite element (FE) model was used to analyze the behavior of pavement layers subjected to dynamic loadings. The model was loaded with an incremental contact pressure from 50 to 550 kPa with different variable such as water table level (1,2 and 3m), suction of soil and degree of saturation (100, 90, 80, 70 and 20%). The results indicated that during loading on pavement layer with increases water table level and different degree of saturation the vertical settlement was decreased by about (11, 15, and 18%) for water table level= 1m, (9, 13, 16%) for water table level= 2m and (28%) for water table level= 3m (dry soil) respectively. The effect of degree of saturation on the vertical settlement is apparent at the lower value for water table level (1 and 2m) and the vertical settlement is decreased with increasing soil suction. The results also show the negative pore water pressure decreased with decreased of degree of saturation and development increases with depth and beginning of dynamic load. The effect of unsaturation greater at the center line of pavement layer and limited far away the center line.

Field Experiments to Test the Elevated Water Table Concept Combined with a Desulfurized Tailings Cover Layer

2016 ◽  
Author(s):  
Nicolas J. Rey ◽  
Isabelle Demers ◽  
Bruno Bussière ◽  
Mamert Mbonimpa ◽  
Sylvain Lortie
Keyword(s):  
Water Table ◽  
Field Experiments ◽  
Cover Layer ◽  
Elevated Water Table ◽  
Elevated Water
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