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

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

Canadian Geotechnical Journal ◽

10.1139/cgj-2018-0875 ◽

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.

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

Water Air & Soil Pollution ◽

10.1007/s11270-010-0397-x ◽

2010 ◽

Vol 213 (1-4) ◽

pp. 437-458 ◽

Cited By ~ 17

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

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Oxygen diffusion and consumption in low-sulphide tailings covers

Canadian Geotechnical Journal ◽

10.1139/t08-132 ◽

2009 ◽

Vol 46 (4) ◽

pp. 454-469 ◽

Cited By ~ 28

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.

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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

Canadian Geotechnical Journal ◽

10.1139/cgj-2020-0622 ◽

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.

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Analyzing the variation of the water table level with 3D numerical simulations to assess reclamation techniques for an acidic tailings impoundment

Canadian Geotechnical Journal ◽

10.1139/cgj-2019-0694 ◽

2020 ◽

Author(s):

Stefan Broda ◽

Marie-Pier Ethier ◽

Daniela Blessent ◽

Michel Aubertin ◽

Abdelkabir Maqsoud ◽

...

Keyword(s):

Water Table ◽

Flow Model ◽

Mine Drainage ◽

Column Tests ◽

Natural Conditions ◽

Sulphide Minerals ◽

Water Table Level ◽

Tailings Impoundment ◽

The Impact ◽

Produce Acid

Tailings with sulphide minerals exposed to oxygen and water can oxidize and produce acid mine drainage (AMD). This study evaluated the impact of natural conditions and of a thin cover deposition on the water table level, for selecting the reclamation technique to control AMD on the elevated portion of an abandoned tailings impoundment. The reactive tailings were partly covered with alkaline tailings transported as a pulp from a nearby mine. A 3D numerical variably-saturated groundwater flow model of the tailings impoundment and its surrounding area was built. The simulation results reproduced well the field observations before, during and after the deposition of a thin layer of tailings. The calibrated model was then used to forecast the evolution of the water table position for the next 100 years, under various site conditions, including a period of 5 years with dry summers. The results show that the water table levels are in average several meters below the interface between the reactive tailings and the cover, thus failing to meet the target criterion to control the production of AMD determined from previous column tests. The results are analyzed and discussed in terms of the site configuration and atmospheric recharge.

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Relationship Between Botanical Composition, Nitrogen Response, and Water Table Level on Wet Meadow Sod 1

Agronomy Journal ◽

10.2134/agronj1959.00021962005100090017x ◽

1959 ◽

Vol 51 (9) ◽

pp. 562-565

Author(s):

M. G. Klages ◽

J. A. Asleson

Keyword(s):

Water Table ◽

Botanical Composition ◽

Nitrogen Response ◽

Wet Meadow ◽

Water Table Level

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Automatic Control of Water Table Level in Soil Tanks

Soil Science Society of America Journal ◽

10.2136/sssaj1968.03615995003200040048x ◽

1968 ◽

Vol 32 (4) ◽

pp. 596-598

Author(s):

C. R. Willey

Keyword(s):

Automatic Control ◽

Water Table ◽

Water Table Level

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Surface and subsurface flow effect on permanent gully formation and upland erosion near Lake Tana in the northern highlands of Ethiopia

Hydrology and Earth System Sciences ◽

10.5194/hess-14-2207-2010 ◽

2010 ◽

Vol 14 (11) ◽

pp. 2207-2217 ◽

Cited By ~ 94

Author(s):

T. Y. Tebebu ◽

A. Z. Abiy ◽

A. D. Zegeye ◽

H. E. Dahlke ◽

Z. M. Easton ◽

...

Keyword(s):

Water Table ◽

Gully Erosion ◽

Grazing Land ◽

Cross Sectional ◽

Lake Tana ◽

Erosion Rates ◽

Remotely Sensed Imagery ◽

Reservoir Siltation ◽

Upland Erosion ◽

Elevated Water

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.

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The biology of two species of Engaeus (Decapoda : Parastacidae) in Tasmania. III. Habitat, food, associated fauna and distribution

Marine and Freshwater Research ◽

10.1071/mf9770095 ◽

1977 ◽

Vol 28 (1) ◽

pp. 95 ◽

Cited By ~ 25

Author(s):

PJ Suter ◽

AMM Richardson

Keyword(s):

Dissolved Oxygen ◽

Geographical Distribution ◽

Water Table ◽

Freshwater Crayfish ◽

Associated Fauna ◽

Water Table Level ◽

Burrow Structure ◽

Study Sites ◽

North Western ◽

Temperature Water

The habitats of two apparently sympatric freshwater crayfish, Engaeus cisternarius and E. fossor, in north-western Tasmania were compared. At two study sites data on rainfall, temperature, water table level, dissolved oxygen and pH were collected. E. fossor occupies regions below the water table, whilst E. cisternarius occupies drier areas above the water table. The burrow structure, burrow fauna, ectofauna and food were compared. The geographical distribution of each species is discussed.

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