John W. Molson

Université Laval | ULAVAL · Department of Geology and Geological Engineering

Numerical modelling of a hypothetical geosphere setting in the Canadian Shield is employed to assess the impact of permafrost growth and decay cycles on groundwater flow and thermal conditions relevant to the near and far-field environment of a deep geological repository (DGR). This study aims to examine how transient events linked to long-term cli...

Tailings from Agnico Eagle’s Goldex mine are stored in a tailings pond built in 2007. Used only as a secondary pond since its construction, it will eventually be used as the main facility, which could entail hydrogeological changes in the tailings and surrounding aquifers. To ensure the protection of groundwater during future mine operations, furth...

The motivation for this topic stemmed from practical questions posed to the Regional Groundwater Flow Commission (RGFC) of the IAH regarding assessing transboundary aquifer systems. These questions focused on sedimentary basins which were considered aquifer systems even though the information on hydrogeological units and groundwater flow in the bas...

Plain Language Summary Finding a reliable source of drinking water in very cold climates is a challenging task for the sustainable development of northern communities. On the one hand, surface water is vulnerable to contamination and can freeze in winter. On the other hand, groundwater stored as ice in permanently frozen ground, called permafrost,...

The cover image is based on the Research Article A conceptual model for talik dynamics and icing formation in a river floodplain in the continuous permafrost zone at Salluit, Nunavik (Quebec), Canada by Weibo Liu et al., https://doi.org/10.1002/ppp.2111.

Icing occurs each winter along the floodplain of the Kuuguluk River in the continuous permafrost zone at Salluit in Nunavik (Quebec), Canada. The source of successive water overflows which thicken and enlarge this ice cover over time is suprapermafrost groundwater discharging from a talik below the riverbed. Electrical resistivity tomography was us...

Global demands for energy efficient heating and cooling systems coupled with rising commitments toward net zero emissions is resulting in wide deployment of shallow geothermal systems, typically installed to a depth of 100 to 200m, and in the continued growth of the global ground source heat pump (GSHP) market. Ground coupled heat pump (GCHP) syste...

Quasi-point hydraulic properties (K) measured locally under laboratory or field conditions need to be upscaled to block-scale K-tensors for use in flow simulators. The upscaled model also needs to be calibrated to hydraulic head observations. The calibration must preserve spatial covariance, cross-covariance and non-linear relations between tensor...

Standard Particle Tracking (PT) approaches without Monte-Carlo will not represent the underlying subsurface uncertainty and will always provide smaller well capture zones. PT based on a single flow simulation can still be used as an initial screening tool, however, water management decisions should not be based on only one model realization. Our cr...

Passive carbon mineralization in ultramafic mining residues, which allows the sequestration of CO2 through carbonate precipitation, is one of the options being considered to limit the accumulation of anthropogenic CO2 in the atmosphere. The Dumont Nickel Project (DNP) will generate approximately 1.7 Gt of utramafic mining residues over 33 years of...

En raison de son isolement avec le reste de la province, l'archipel des Îles-de-la-Madeleine doit produire, de façon autonome, l'électricité et la chaleur nécessaire pour ses habitants en consommant des combustibles fossiles. La présente étude a pour objectif d'évaluer les ressources géothermiques contenues dans le sous-sol et ainsi, permettre leur...

A Null‐Space Monte‐Carlo (NSMC) approach was applied to account for uncertainty in the calibration of the hydraulic conductivity (K) field for a three‐dimensional groundwater flow model of a major water supply system in Switzerland. The approach generates different parameter realizations of the K field using the pilot point methodology. Subsequentl...

Detection and quantification of groundwater flow in fractures is challenging due to its irregular distribution and fine scale, requiring intensive and depth-discrete field data collection along boreholes. This study presents a new method using fiber optic active distributed temperature sensing (A-DTS) in sealed boreholes to efficiently quantify dep...

Although hydrological observations over the past several decades have provided ample evidence that water resources can be strongly affected by climate change (Bates et al., 2008), our present understanding of how these predicted alterations impact subsurface water resources and flow systems, and our knowledge about the dynamic relationship between...

Interactions of basin-scale topography-driven groundwater flow and free thermal convection were examined by two-dimensional theoretical numerical model simulations for a homogeneous unit basin. The continuity equations for flow with temperature-dependent water density and thermal transport were solved to handle the problem. The simulations showed t...

In regional hydrostratigraphic systems, heterogeneities in hydraulic conductivity (K) play a central role for flow velocities and contaminant transport modelling. Typical field measurements of K usually only represent one or at most a few local hydrofacies of a single hydrostratigraphic unit (HSU). At the regional scale, numerous HSUs exist, each s...

Magnesium rich minerals that are abundant in ultramafic mining waste have the potential to be used as a safe and permanent sequestration solution for carbon dioxide (CO2). Our understanding of thermo-hydro-chemical regimes that govern this reaction at an industrial scale, however, has remained an important challenge to its widespread implementation...

Numerical simulations of coupled groundwater flow and heat transport are used to address how hydrogeological conditions can affect permafrost dynamics. The simulations are based on a two-dimensional vertical-plane conceptual model of a study site at the Iqaluit Airport, Nunavut, Canada, which includes a 50 m deep permafrost terrain with a shallow a...

The generation of acid mine drainage (AMD) remains a major environmental challenge for the mining industry. The reclamation of old mine sites with pre-oxidized tailings is particularly challenging because of indirect oxidation reactions which can limit the overall effectiveness of an oxygen barrier to prevent AMD. The goal of this project was to qu...

As part of the Quebec PACES III provincial groundwater resources assessment programme (Programme d’acquisition des connaissances en eaux souterraines), a regional-scale two-dimensional numerical groundwater model was developed in the Chaudière-Appalaches region, Québec, Canada. The model considers groundwater flow, transport of groundwater age and...

Hydrological observations over the past several decades have provided ample evidence that water resources can be strongly affected by climate change (Bates et al., 2008), however our present understanding of how these changes may impact subsurface water resources and flow systems, and our knowledge about the dynamic relationship between groundwater...

The abstract of this work is provided in the "Linked Research" section below.

In high-elevation, boreal and arctic regions, hydrological processes and associated water bodies can be strongly influenced by the distribution of permafrost. Recent field and modeling studies indicate that a fully-coupled multidimensional thermo-hydraulic approach is required to accurately model the evolution of these permafrost-impacted landscape...

Variations of hydraulic conductivities (K) in hydrostratigraphic systems may significantly affect the flow velocity field and mass dispersion. Field data used for assessment of K are generally representative at a local scale only and for one or a few hydrofacies forming a specific hydrostratigraphic unit (HSU). Regional groundwater flow systems enc...

The delineation of wellhead protection areas (WHPAs) under uncertainty is still a challenge for heterogeneous porous media. For granular media, one option is to combine particle tracking (PT) with the Monte Carlo approach (PT-MC) to account for geologic uncertainties. Fractured porous media, however, require certain restrictive assumptions under th...

Climate variability and change directly influence groundwater systems through changes in precipitation, evapotranspiration, and therefore recharge. Relative changes in either groundwater or surface water levels can modify the interaction between groundwater and surface water, which can directly affect wetlands and other groundwater-dependent ecosys...

Climate change can directly influence groundwater systems through modification of recharge. Affecting not only groundwater levels and flow dynamics, climate change can also modify the fragmentation and hierarchy of groundwater flow systems. In this study, the influence of climate change - impacted recharge on groundwater levels and on inter-connect...

A two-dimensional vertical-section numerical model for groundwater flow and transport using age, tritium and chloride was used to help validate a conceptual model of geochemical evolution within a representative regional-scale hydrogeological system in the Outaouais Region, Quebec, Canada. The flow system includes up to 30 m of Quaternary sediments...

This study focuses on the reclamation work being performed on two former acid-generating tailings sites, located in Quebec, Canada. At both sites, the tailings were partially oxidized due to extended exposure, and the pore water is acidic. The reclamation solution applied to control acid mine drainage is a monolayer cover, made of non acid-generati...

Mg-rich process tailings and waste rocks from mining operations can react spontaneously with atmospheric CO2 to form stable carbonate minerals by exothermic reactions. Over the last decade, we have conducted a number of laboratory and field experiments and surveys on both mine waste rocks and different types of mine tailings from Ni-Cu, chrysotile,...

A conceptual and numerical model of seawater invasion and subsequent leaching have been developed to understand the processes involved in the evolution of groundwater salinity within a regional sedimentary rock aquifer system. In the St. Lawrence Valley, large paleo-environmental changes have occurred during the last glacial-deglacial cycle and the...

This study addresses the delineation of areas that contribute baseflow to a stream reach, also known as stream capture zones. Such areas can be delineated using standard well capture zone delineation methods, with three important differences: (1) natural gradients are smaller compared to those produced by supply wells and are therefore subject to g...

The efficiency of a monolayer cover to prevent acid mine drainage (AMD) generation from two pre-oxidized tailings impoundments was assessed using the MIN3P code, a finite volume model for coupled groundwater flow, oxygen diffusion and multi-component reactive transport. Numerical simulations were validated using large column tests set up in the lab...

Numerical simulations of groundwater flow and heat transport are used to provide insight into the interaction between shallow groundwater flow and thermal dynamics related to permafrost thaw and thaw settlement at the Iqaluit Airport taxiway, Nunavut, Canada. A conceptual model is first developed for the site and a corresponding two-dimensional num...

In recent years, concerns have been raised about the potential environmental impacts of oil and gas (O&G) exploitation, especially regarding groundwater resources. However, there have been few studies carried out to assess the actual risk of O&G exploitation based on specific local conditions. This paper reports on a study aiming to assess the pote...

The rate of permafrost degradation in northern Quebec, Canada, has increased over the last two decades due to climate warming, which is expected to significantly modify the hydrogeologic and thermal regimes. Groundwater accessibility is also expected to increase and could become a significant source of drinking water for northern communities. In th...

This study addresses the delineation of areas that contribute baseflow to a stream reach, also known as stream capture zones. Such areas can be delineated using standard well capture zone delineation methods, with three important differences: (1) natural gradients are smaller compared to those produced by supply wells and are therefore subject to g...

Hydrogeological processes acting at the margins of confined and unconfined thick carbonate sequences are particularly interesting due to a complex system evolution including partial uplift of fully confined carbonate systems and subsequent erosion of cover layers. We provide insights into this evolution by simulating coupled density-dependent fluid...

A quantitative reconstitution scenario has been developed for the evolution of groundwater salinity within a regional aquifer system following deglaciation. In our study area, Montérégie Est (~9 000 km2, in southern Quebec, Canada), brackish groundwater at shallow depths is related to large palaeoenvironmental changes that took place over North Ame...

The Buda Thermal Karst of Hungary is characterised by a special hydrogeological context, since it is situated at the margin of unconfined and confined carbonate systems. Many studies have been made in order to gain insight into the recent hydrogeological system as well the paleo-fluid migration processes, therefore extensive geological, speleologic...

Cette étude constitue l’étude E3-10 du plan de réalisation de l’étude environnementale stratégique (ÉES) sur les gaz de schiste. Elle a pour objectif d’identifier et d’évaluer les mécanismes de migration du méthane, des fluides de formation et des fluides de fracturation vers les aquifères superficiels d’eau douce en relation avec les activités de...

Three-dimensional numerical simulations are used to provide insight into the behavior of methane as it migrates from a leaky decommissioned hydrocarbon well into a shallow aquifer. The conceptual model includes gas-phase migration from a leaky well, dissolution into groundwater, advective-dispersive transport and biodegradation of the dissolved met...

Water availability and management issues related to the supply of drinking water in northern communities are problematic in Canada. While rivers and lakes are abundant, they are vulnerable to contamination and may become dry in winter due to freezing. Groundwater can often provide a more secure and sustainable water source, however its availability...

Two experimental small-scale cells have been constructed in the field to better understand passive mineral carbonation under natural atmospheric conditions in the ultramafic milling wastes of Thetford Mines (Québec, Canada). The magnesium-rich milling wastes mainly consist of poorly sorted grains and fibers of lizardite and chrysotile, with smaller...

Cette étude paléo-hydrogéologique propose une reconstitution quantitative de l'évolution des conditions souterraines hydrodynamiques et hydrochimiques du système aquifère de la Montérégie Est par la modélisation hydrogéologique numérique, avec comme objectif principal d'étudier la migration souterraine des sels dissous provenant de la Mer de Champl...

The modeling of freezing and thawing of water in porous media is an area of increasing interest. Examples include the modeling of permafrost degradation due to climate change, geotechnical applications in tunneling, and borehole heat exchanger performance in cold regions. Different code implementations have been developed and an interest has arisen...

Natural weathering of ultramafic rocks in mine tailings allows the sequestration of atmospheric CO 2 through the formation of magnesium carbonates. In this context, the Dumont Nickel Project (DNP) is of particular interest as it will generate 1.7 Gt of ultramafic residues. A field experiment has been conducted at the DNP site in order to estimate i...

Methane and brine leakage rates and associated time scales along the cemented casing of a hypothetical decommissioned shale-gas well have been assessed with a multi-phase flow and multi-component numerical model. The conceptual model used for the simulations assumes that the target shale formation is 200 m thick, overlain by a 750 m thick caprock,...

In the Haldimand sector of Gaspé, Québec, Canada, a study was carried out to assess the potential risk on a shallow fractured rock aquifer system due to development of a tight sandstone petroleum reservoir. Petroleum exploration wells are being drilled in the forested core of a hilly 50 km2 peninsula by the sea (up to 200 m amsl) and where local re...

Numerical simulations have provided new insights into the processes controlling fluid flow and heat transport within the deep and thick carbonate system of the Buda Thermal Karst, which can be considered as a pilot area to examine the importance of these driving forces. Different model scenarios of four cases were tested to represent snapshots of t...

The identification and removal of data outliers remains a major challenge for spatial analysis of piezometric data. In this context, a simple semi-automated procedure for filtering outliers of depth to static water level was developed and used as a part of a regional groundwater-mapping project in the Québec Metropolitan Community, Québec, Canada....

The impacts of climate change in boreal regions has received considerable attention recently due to the warming trends that have been experienced in recent decades and are expected to intensify in the future. Large portions of these regions, corresponding to permafrost areas, are covered by water bodies (lakes, rivers) that interact with the surrou...

Study region: This study is conducted in the Magdalen Islands (Québec, Canada), a small archipelago located in the Gulf of St. Lawrence. Study focus: This work was undertaken to support the design of a long-term groundwater monitoring network and for the sustainable management of groundwater resources. This study relies mostly on the compilation of...

A conceptual model was developed for a hydrogeological flow system in the southern Outaouais Region, Quebec, Canada, where the local population relies heavily on groundwater pumped from shallow overburden aquifers and from deeper fractured crystalline bedrock. The model is based on the interpretation of aqueous inorganic geochemical data from 14 we...

Revue de divers aspects liés à la stabilité géotechnique des ouvrages de retenue de résidus miniers Partie i-Mise en contexte et caractéristiques générales RESUME Les digues construites pour les parcs à résidus miniers doivent être conçues de façon à pouvoir supporter les charges critiques anticipées durant l'opération de la mine et après sa fermet...

Ce rapport et les produits cartographiques qui l’accompagnent représentent les résultats d’un projet réalisé conjointement par le Centre Eau Terre Environnement de l’INRS (INRS-ETE), par l'Institut de recherche et développement en agroenvironnement (IRDA) et par le Regroupement des organismes de bassins versants de la Chaudière-Appalaches (OBV-CA)....

http://geoscan.ess.nrcan.gc.ca/starweb/geoscan/servlet.starweb?path=geoscan/fullf.web&search1=R=295674

The carbonation of chrysotile and nickel mining residues was studied under ambient laboratory conditions to assess their response under various potential field conditions (pore saturation, watering episodes, temperature, CO2 diffusion, and dissolved oxygen) and to a variety of natural and chemical enhancers (sulfide minerals, brucite, chelate ligan...

Early diagenetic silica is distributed unevenly in Phanerozoic sponge-spicule-rich carbonate mounds. In Paleozoic mounds, replacive silica occurs principally at the microscopic scale, whereas in Mesozoic strata, it is frequently present as nodular chert. This paper explores the possibility of advective–dispersive loss of dissolved pore-water silica...

As part of a province-wide groundwater characterization program, a detailed groundwater geochemistry survey was undertaken in the Outaouais Region (Québec, Canada) in order to identify the primary processes responsible for groundwater quality and to develop a conceptual model for groundwater flow and geochemical evolution. During the summers of 201...

Cluster analysis of springs as natural discharge points based on statistical data, and a comparison of the results with simulated flow distributions can help provide insight into natural deep carbonate groundwater flow systems and on the hydraulic role of various structures and hydrostratigraphic units. The Transdanubian Range is located in the cen...

The mineral carbonation of five different ultramafic mining residues was studied experimentally, namely chrysotile (Black Lake mine [Bl] and Asbestos mine [Asb]), nickel (Ni–Cu Dumont mine project [Du] and Raglan Ni–Cu–EGP mine [Rgl]) and diamond mine residues (Renard mine project [Rnd]). The CO2 uptake, gas volume and mining residue physical and c...

Intensive mining activities in Canada have opened up a potentially resourceful opportunity into atmospheric and industrial CO2 capture. The use of mining residues under ambient conditions as CO2 sinks offers all the benefits of CO2 mineral sequestration. It also stands out as the most affordable approaches in the CCS arsenal to sustainably and safe...

Modelling has played a key role in the evolution of insights on the Waterloo Moraine groundwater system as a water source for Waterloo Region. As models evolved over the last four decades, so did new insights. Starting from a simple layer-cake concept, models eventually became three-dimensional, while the focus changed from well interference to mul...

http://www.tandfonline.com/eprint/gvejx9RMDZbJKTgSXsFd/full#.VL6kTEeG9KY

A detailed study of the sensitivity of mineral carbonation to temperature variations and air oxygen content in a saturated nickel mining residue (NiMR) under humid environments was carried out. The dynamics of CO2 uptake in NiMR beds subjected to carbonation was monitored as a function of temperature and oxygen content in the range 10–40 °C and 0–2...

The study presented here focuses on the use of monolayer covers for reclaiming two acid-generating tailings sites located in Quebec, Canada. One of these covers is made of non-acid-generating tailings, and the other is made of a silty sand (till). The covers are part of the closure plans that aim at controlling acid mine (rock) drainage at these tw...