Pre-Feasibility Report of the ESI Closure Working Group ...This report presents the pre-feasibility...

Pre-Feasibility Report of the ESI Closure Working Group June 2014

C L O S U R E W O R K I N G G R O U P | P R E - F E A S I B I L I T Y S T U D Y R E P O R T

CM I C E S I CW G | P R E - F E A S I B I L I T Y S T U D Y R E P O R T 2

Table of Contents

Table of Contents .................................................................................................................................. 2

List of Figures ........................................................................................................................................ 3

List of Tables ......................................................................................................................................... 3

1 Executive Summary ....................................................................................................................... 4

1.1 Overview ................................................................................................................................ 4

1.2 Standardized Closure Criteria for Mine Site Relinquishment ................................................... 4

1.3 Passive Systems to Reduce / Eliminate the Effects of ARD .................................................... 4

1.4 Project Selection and Risk Assessment .................................................................................. 5

2 Introduction .................................................................................................................................... 5

2.1 Background ............................................................................................................................ 5

2.2 Project Involvement ................................................................................................................ 6

2.3 Project Schedule .................................................................................................................... 7

2.4 Project Selection Workshop .................................................................................................... 7

3 Pre-feasibility Study Objectives .................................................................................................... 8

4 Problem Statements ...................................................................................................................... 8

4.1 Standardized Criteria for Mine Site Relinquishment ................................................................ 8

4.2 Passive Systems for Acid Rock Drainage ............................................................................... 9

5 Standardized Closure Framework for Relinquishment .............................................................. 10

5.1 Overview .............................................................................................................................. 10

5.2 Saskatchewan ...................................................................................................................... 10

5.3 Québec ................................................................................................................................ 13

5.4 Ontario ................................................................................................................................. 15

5.5 British Columbia ................................................................................................................... 16

5.6 Alberta ................................................................................................................................. 17

5.7 Gaps in Current Practice ...................................................................................................... 21

5.8 Conclusion ........................................................................................................................... 24

6 Passive Treatment Systems for Acid Rock Drainage ................................................................. 24

6.1 Existing Systems .................................................................................................................. 24

6.2 Advancement in Technology and Development .................................................................... 42

6.3 Gaps in Technology and Research ....................................................................................... 47

7 Project Selection Workshop ........................................................................................................ 50

7.1 Overview .............................................................................................................................. 50

7.2 Risk Assessment .................................................................................................................. 51

7.3 Assessment Criteria ............................................................................................................. 54

7.4 Conclusions / Recommendations.......................................................................................... 54

8 References ................................................................................................................................... 55



List of Figures

Figure 1 – Typical Alberta well site ........................................................................................................ 19

Figure 2 – Stages of Closure Planning .................................................................................................. 22

Figure 3 – General Selection Process for ARD Passive Treatment Systems.......................................... 26

Figure 4 – Selection Criteria for Passive Treatment Technologies ......................................................... 27

Figure 5 – Free Water Surface Constructed Wetland............................................................................. 28

Figure 6 – Constructed Wetland Cells Showing Potential Flow Paths .................................................... 29

Figure 7 – Anaerobic Wetland Treatment System.................................................................................. 31

Figure 8 – Anaerobic Wetland Treatment System.................................................................................. 31

Figure 9 – General Schematic of a Vertical Flow Wetland System ......................................................... 32

Figure 10 – Sulfate-reducing Bioreactor System .................................................................................... 33

Figure 11 – Schematic of Anoxic Limestone Drains ............................................................................... 35

Figure 12 – Schematic View of a Limestone Diversion Well ................................................................... 36

Figure 13 – Limestone Leach Bed Treatment System ........................................................................... 37

Figure 14 – Slag Leach Bed Treatment System .................................................................................... 37

Figure 15 – Cross-Sectional of a Permeable Reactive Barrier ............................................................... 38

Figure 16 – Microbial Fuel Cell for ARD ................................................................................................ 43

Figure 17 – Schematic of Microbial Fuel Cell for ARD ........................................................................... 43

Figure 18 – GaRDS Bioreactor (Taylor et al. 2005: 31). ......................................................................... 44

Figure 19 – Installation of Low Permeability Well and Drainage system. ................................................ 45

Figure 20 – Risk Assessment Components ........................................................................................... 51

Figure 21 – Likelihood-Consequence Risk Matrix .................................................................................. 52

List of Tables

Table 1 – Closure Working Group Members ............................................................................................ 7

Table 2 – CEMA Proposed Reclamation Criteria ................................................................................... 20

Table 3 – Phytoremediation Technologies ............................................................................................. 39

Table 4 – Risk Assessment Results for the Standardized Closure Criteria for Relinquishment ............... 53



1 Executive Summary

1.1 Overview

This report presents the pre-feasibility work of the Closure Working Group (CWG) – one of three

working groups of the Environmental Stewardship Initiative (ESI) of the Canada Mining Innovation Council

(CMIC).

The objective of the report is to determine the initial feasibility of two project concepts:

1. Standardized closure criteria for mine site relinquishment

2. Passive systems to reduce / eliminate the effects of acid rock drainage (ARD)

1.2 Standardized Closure Criteria for Mine Site Relinquishment

Mine closure is an amorphous concept with no defined end point in many instances, which is often

related to the environmental regulatory environment and the application by regulators. The lack of

defined relinquishment criteria can lead to the management of sites in perpetuity. Should the company

dissolve or mineral rights leases and/or permits expire, the responsibility for closure and rehabilitation

would then revert to the Crown.

The development of standardized closure criteria will provide a clear path to achieving the end-goal

of relinquishment. In turn, this will provide certainty for operators and stakeholders regarding mine

closure, will allow for more progressive rehabilitation planning and implementation, and will help reduce

the incidence of abandoned mines accruing to the Crown.

All jurisdictions provide for the return of mine sites to the Crown, although the legislation and

regulations differ across jurisdictions. Some jurisdictions (e.g. Saskatchewan) have comprehensive

programs for relinquishment, while most others have brief stipulations in environmental legislation. The

legislation / regulations differ based on liability, specific requirements, and financial assurances (among

others). However, despite most jurisdictions having de jure stipulations for relinquishment, very few

recently closed mines have been returned to the Crown. One jurisdiction – Alberta – has developed

standardized criteria and associated indicators for the return of oil sands sites to the Crown.

The main gaps related to achieving mine site relinquishment fall under two general categories:

Legislative / regulatory; and, Technical in mining, reclamation, and closure practices.

1.3 Passive Systems to Reduce / Eliminate the Effects of ARD

ARD has the potential to be one of the costliest environmental effects affecting the mining industry.

The greatest potential risk of ARD to the receiving environment is the sulphate and metal contamination

associated with the low pH leaving operational and closed sites and entering surface water and ground

water.



Practices to stop / treat ARD are typically divided into either ‘active’ or ‘passive / semi-passive’

treatment. Passive systems are generally considered attractive to stop / treat ARD due to their lower costs

of construction, operation, and maintenance, as well as their ability to operate at remote locations with

limited operational requirements (MEND 1999: 1).

Some 15 predominant passive / semi-passive systems were identified and recent advancements

related to ARD management were also presented. Additionally, some of the major gaps related to the

operation of the above systems across Canada were identified, including:

Existing reliance on treatment in perpetuity;

System performance in cold / winter climates; and

Long-term performance and maintenance.

The CWG determined that there were outstanding issues uncovered as part of the pre-feasibility

research (including the gaps outlined above). These issues need to be further addressed before an

appropriate risk assessment is possible.

Accordingly, the ESI plans to work in conjunction with a graduate student under the guidance of a

professor specializing in passive systems for ARD. Once the research is completed, it is anticipated that a

more thorough risk assessment would be conducted that will enable the group to make a

recommendation as to whether or not the project should be taken to the feasibility level.

1.4 Project Selection and Risk Assessment

A project selection workshop was held to assess the two project concepts and determine which

should be taken to the feasibility level. As part of the workshop, a risk assessment was conducted for the

closure criteria project, which uncovered some risks that may prevent the project from succeeding.

Management responses were formulated to mitigate these risks.

Based on the results of the workshop, the Closure Working Group made a recommendation that a

feasibility study should be conducted for the standardized closure criteria project. The study will being in

June 2014 and should be completed by end-2014.

2 Introduction

2.1 Background

The Environmental Stewardship Initiative (ESI) of the Canada Mining Innovation Council (CMIC) is

an industry-led consortium comprised of approximately 25 members from industry and government.

Initiated in early 2012, the ESI’s mandate is to develop – through step-change technological innovation,

project development, and multi-stakeholder collaboration – solutions to some of the myriad

environmental, sustainability, and competiveness issues facing the Canadian mining industry.



The first phase of the ESI’s work was for Hatch Ltd to complete a scoping study outlining some

potential areas where environmental research, development, and innovation are required.1 Several multi-

stakeholder surveys were also conducted in September 2012 to ascertain stakeholder needs and priorities

in terms of research and innovation. Based on the results of the studies and ongoing collaboration through

CMIC workshops, the following concepts were selected for project development under the aegis of three

ESI working groups:

Water Working Group (WWG)

Integrated remote sensor for surface / groundwater quality and quantity monitoring,

including baseline, operations, and post-closure monitoring;

Database / repository of water resources information (i.e. physical, chemical, and

biological properties);

Tailings Working Group (TWG)

Production of benign tailings (i.e. stabilization or removal of contaminants prior to

placement);

In situ stabilization / remediation of contaminants within existing tailings;

Closure Working Group (CWG)

Development of a standardized framework for closure criteria; and,

Reduction / elimination of the effects of acid rock drainage.

The following pre-feasibility study represents the second phase of project development for the CWG.

2.2 Project Involvement

The pre-feasibility study reports for each working group were prepared by an individual, independent

consultant of CMIC in collaboration with the above working groups. In-kind contributions were provided

by the members of the ESI as members of the respective working groups, including document review and

input, meetings, and workshop participation. The composition of the closure working group is presented

in Table 1 below.

1 http://www.cmic-ccim.org/wp-content/uploads/2013/07/HatchScopingReport1.pdf



TABLE 1 – CLOSURE WORKING GROUP MEMBERS

MEMBER ORGANIZATION

Robert Holmes (Chair) Government of Yukon

Mark Thorpe (ESI Chair) Golden Star Resources

Scott Davidson New Gold

Mike Aziz Goldcorp

Heather MacDonald CH2M HILL

Karen Chovan Independent

Robert Reisinger CH2M HILL

Bryan Schreiner Saskatchewan Research Council

Ian Wilson Saskatchewan Research Council

Heli Aatelma Government of Yukon

2.3 Project Schedule

The pre-feasibility work started in January 2014 following some initial work in late 2013 and was

conducted over the course of approximately four months. Ongoing meetings / workshops were conducted

among ESI members (typically monthly) and among the individual working groups beginning in 2013. An

in-person workshop was conducted in early March 2014 in Toronto to review preliminary pre-feasibility

work towards completion of the pre-feasibility studies. Culminating workshops involving working group

members were held in May 2014 to assess the results of the studies and to select projects for further

project development.

It is planned that the feasibility study will be conducted immediately following the completion of the

pre-feasibility study and should be completed within 2014. Additional project development activities will

be outlined as part of this work.

2.4 Project Selection Workshop

A culminating, in-person workshop was held among the members of the CWG in Vancouver on 13

May 2014. The primary purpose of the workshop was to finalize the results of the pre-feasibility study,

which enabled the group to make a decision as to the initial feasibility of the project concepts. To do so,

the workshop was organized around two primary exercises:

1) Conducting a risk assessment of the projects

2) Screening the projects against assessment criteria to allow for prioritisation

In turn, the workshop enabled the group to determine the preliminary elements of the subsequent

feasibility studies. A summary of the workshop is presented in Section 7.



3 Pre-feasibility Study Objectives

The objectives of the pre-feasibility study are as follows:

Introduce the selected subjects; Identify associated challenges and risks; Determine optimal pathways for future activities; and, Select projects that will provide accessible step changes in the mining business.

The selected projects will then undergo feasibility analyses. These analyses will allow the ESI to

further prioritize its focus areas with the aim of developing a comprehensive development program

directed by industry through CMIC.

Lastly, the studies will serve as a basis for attracting stakeholder support and funding for the ESI’s

ongoing project development activities, including support from industry, government, and academia

(among others).

4 Problem Statements

4.1 Standardized Criteria for Mine Site Relinquishment

Mine closure involves decommissioning and rehabilitation activities that are conducted – typically

progressively – in preparation for the cessation of mining and processing activities at a particular site.

These activities are carried out in accordance with mine closure plans, which are required by most

jurisdictions before the start of mine development activities. Mine closure and asset retirement

obligations are updated as mining proceeds. Mine closure plans aim to ensure that sites are restored to a

suitable post-mining land-use in which the risks to the receiving environment and human health and

safety are minimized. Financial assurances are usually required by governments with the aim of ensuring

that funding is available for the associated costs of the closure and rehabilitation activities.

Although all mining companies are engaged in such activities, mine closure and rehabilitation remains

an amorphous concept with no defined end in many instances. This is often related to environmental

legislation. Detailed closure planning and the associated implementation activities are also often deferred

by operators to later in the operational life of the mine. The lack of a defined end can lead to management

of the sites in perpetuity, and, should the company dissolve or mineral rights leases and/or permits expire,

the responsibility for closure and rehabilitation reverts to the Crown. Evidence of this can be seen in the

number of abandoned and orphaned mine sites across all jurisdictions in Canada (i.e. 10,000+) (NOAMI

2010: 2).

Based on the lack of certainty that sites can be relinquished in many jurisdictions, CMIC members

prioritized the development of a closure and rehabilitation criteria framework with the end goal of

rehabilitated site relinquishment to the Crown. All jurisdictions allow for relinquishment to take place

(nine through a legislative act), although in reality this is rarely achieved. For example, in Ontario, no mine

site has been relinquished under the current regulatory framework (a review process is now underway).

In Saskatchewan, there is an Institutional Control Program (ICP) for mine and mill site relinquishment that



has been effectively used for the relinquishment of five uranium mine sites and one gold mine site. The

Saskatchewan program may serve as a model for the development of the proposed closure and

rehabilitation framework.

Critical to achieving an accepted framework is greater front-end emphasis on mine closure and

rehabilitation. Specifically, a major implementation gap identified in preliminary work was limited

consideration – including technical, financial2, and operational – for mine closure and rehabilitation in the

early stages of mine development evaluation (i.e. preliminary economic assessments, feasibility studies,

etc.). Doing so would allow for an increased understanding of rehabilitation and closure needs and

requirements (including costs) resulting in a more accurate assessment of project economics and long-

term project viability. In turn, costly, unforeseen events related to rehabilitation and closure can be better

accounted for and more effectively managed.

Ultimately, the overriding goals of developing the proposed standardized framework are a reduction

in environmental and socioeconomic risks and associated costs, a reduction in adverse environmental

effects (including costly, unforeseen liabilities), a more secure investment environment, and the

promotion of stakeholder / public confidence for mining.

The overall objectives of mine closure are to:

Prevent or minimise risks to human health and safety;

Minimise adverse long-term environmental, physical, social, and economic impacts;

Achieve water quality objectives;

Create a stable landform suitable for some agreed-upon subsequent land use;

Develop a site that is suitable for return to the Crown.

4.2 Passive Systems for Acid Rock Drainage

Acid rock drainage (ARD) has the potential to be one of the costliest and most severe environmental

impacts associated with a mine’s development, operation, and closure. The cost of ARD remediation at

mine sites in North America has been estimated in the tens of billions of dollars with many individual

mines facing post-closure ARD liabilities upwards of tens of millions of dollars (GARD Guide n.d.). The

greatest potential risk of ARD to the receiving environment is the sulphate and metal contamination

associated with the low pH leaving operational and closed sites and entering surface water and ground

water.

ARD has the potential to continue indefinitely. In fact, many Roman-era mines continue to produce

ARD to this day. Thus, there is the possibility of ARD-affected water requiring treatment in perpetuity,

which inevitably entails high financial costs associated with the work required to remove the potential

contaminants.

2 For example, a reliance on discounted cash flow return on investment (DCFROI) may encourage the postponement of reclamation and closure costs, thereby discouraging progressive reclamation.



Accordingly, industry best practice for the management of ARD has an initial focus on avoidance and

prevention. Where avoidance is not possible, and where it is deemed that the processes can be managed

such that the environmental attenuation limit will not be exceeded, a variety of treatment / mitigation

practices have been developed.

Typically, these practices are divided into either ‘active’ or ‘passive / semi-passive’ treatment; active

treatment typically involves the addition of alkaline chemicals to neutralize the acidity, whereas passive /

semi-passive treatment involves reliance on biological, geochemical, and gravitational processes (Zipper

et al. 2011).

The focus of the following study will be on passive treatment systems. These systems are generally

considered attractive to stop / treat ARD due to their lower costs of construction, operation, and

maintenance, as well as their ability to operate at remote locations with limited operational requirements

(MEND 1999: 1). In a survey conducted by MEND (Zinck and Griffith 2013: 13-17), passive treatment

systems were found to have the lowest associated capital expenditures among the ARD treatment

systems that are used across Canadian mining sites. Lastly, consideration will be given to technologies

that promote walkaway / relinquishment closure scenarios, which will tie in with the first component of

this pre-feasibility work (i.e. standardized framework / criteria for closure).

5 Standardized Closure Framework for Relinquishment

5.1 Overview

Many jurisdictions around the world – including all jurisdictions in Canada – allow for the return of

mining lands to the Crown after a site has been closed out. However, very few of these jurisdictions have

an established regulatory framework for achieving this. As mentioned, an exception to this is

Saskatchewan’s ICP. This program, as well as additional examples from other Canadian and world

jurisdictions, may serve as models for the development of the proposed framework. By understanding the

criteria through which particular sites were able to be returned to the Crown (or relevant body), it is

desired that standardized criteria and hand-over mechanisms can be developed that can be applied to all

Canadian jurisdictions.

The following sections outline the legislation and associated processes for mine site relinquishment

for the major mining jurisdictions in Canada. A specific focus is given to the Saskatchewan ICP given its

comprehensiveness.

5.2 Saskatchewan

Overview of Legislation

The Reclaimed Industrial Sites Act (RISA) and its associated regulations were enacted in 2007 to

“establish a uniform framework for returning Crown land held under surface lease back to the Province

when industrial activities have been completed” (Saskatchewan Ministry of Energy and Resources (MoER),

2012: ii). The development of the act and regulations involved extensive consultation with various



stakeholders, including the Canadian Nuclear Safety Commission (CNSC), the mining industry, Aboriginal

organizations, and the communities in the major mining regions of the province. According to the MoER

(2012: ii), the program was initiated to ensure the “health, safety, and well-being of future generations,

provide greater certainty and closure for the mining industry, [and to] recognize past-stated […] provincial,

national, and international obligations for the storage of radioactive materials”.

To date, six sites have been accepted into the ICP, including five former uranium mine sites and one

former gold operation (all in 2009). From 2012-2017, the MoER expects that two more sites will make

applications for acceptance into the program.

Primary Components

The two primary components of the ICP are the Institutional Control Registry (ICR) and the

Institutional Control Funds (ICFs). The ICR maintains a formal record of closed sites, manages the ICFs, and

performs any required monitoring and maintenance work. This is in accordance with federal and

provincial obligations under the International Atomic Energy Agency (IAEA) Joint Convention on the Safety

of Spent Fuel Management (MoER 2009: 6). There are two separate funds comprising the ICF, namely the

Institutional Control Monitoring and Maintenance Fund (ICMMF) and the Institutional Control Unforeseen

Events Fund (ICUEF). The former is the primary funding mechanism for the ICP, while the latter covers

events such as the failure of a containment dyke, collapse of a pit wall, shaft cover degradation, or a

change in regulatory requirements.

Regulatory Process for Relinquishment

In the context of rehabilitation, closure, and decommissioning activities, mining operations in

Saskatchewan are subject to similar environmental regulations as other Canadian jurisdictions.

Specifically, project proponents are required to submit a conceptual decommissioning and reclamation

plan as part of their initial environmental assessment to the MoER, which may require federal review

under the Canadian Environmental Assessment Act (CEAA). Once the proponent receives federal and

Ministry approval for the project, a detailed decommissioning and closure plan is submitted for review

and approval by the Minister. Financial assurances are also required, as are detailed reviews of the plans

(typically every 5 years, or, 12 months preceding the closure of a facility) (MoER, 2009: 4).

After the cessation of mining and processing activities, and upon completion of the approved

decommissioning and reclamation activities, the site enters a period of ‘transition phase monitoring’,

during which the operator is required to continue monitoring the site at their own expense. The operator

is also required to post financial assurances sufficient to cover the cost of any outstanding obligations, as

well as a contingency for any unexpected occurrences. During this phase, the operator “remains fully liable

for any impacts the site may have on the environment, surrounding communities, and public safety”

(MoER, 2009: 5).

If the site performs in accordance with the decommissioning and reclamation plan, and achieves the

predicted stability (i.e. chemical, biological, and physical stability) during the transition phase, the

operator may make an Application for a Release from Decommissioning and Reclamation. This releases



the company from monitoring and maintenance responsibilities and from the obligation to maintain

financial assurances (although not entirely). Upon approval of the release, the operator may then apply

for a release from its surface lease, which allows for the transfer of custodial responsibility for the property

to the ICP (MoER, 2009: 5). At that time, should the site holder also own the mineral rights associated

with the closed site, the site holder also surrenders those rights to the Minister (MoER 2009: 8).

The federal Canada Nuclear Safety Commission (CNSC) oversees the process for uranium mine sites,

as much of the jurisdiction regarding uranium regulations falls under the purview of the federal

government. This includes regular monitoring of the site activities during the transition phase as well as a

requirement that the CNSC approve the site for acceptance into the ICP by ceasing to regulate the

property.

A site holder cannot be granted complete absolution for site responsibility. The Environmental

Management and Protection Act (EMPA) “provides for absolute liability of a person for a discharge to

continue indefinitely” (MoER 2009: 11). No authority to grant such absolution is provided for in this or any

other relevant provincial legislation. Furthermore, should the site require additional remediation work

that was not accounted for in the plans, additional funds will be required to be posted (CNSC 2013b: 11-

12).

Lastly, planned revisions to the Act and Regulations will allow for the transfer of custodial

responsibility from the ICP to a new company, thereby transferring all current and future liabilities

associated with the site (MoER 2009: 16).

Discussion

A driving force behind the establishment of the ICP was Canada’s international obligations as a

“Contracting Party” to the International Atomic Energy Agency (IAEA) Joint Convention on the Safety of

Spent Fuel Management and on the Safety of Radioactive Waste Management. As the MoER states, as a

Contracting Party to the Convention, “Canada is required to take the steps to ensure that an appropriate

institutional control framework is in place to address the long-term management of decommissioned

uranium mine / mill facilities in Saskatchewan” (MoER 2009: 6).

Furthermore, the history of uranium mining in Saskatchewan may have provided a further incentive

for the establishment of such a program. Historically, a large portion of uranium mining in Saskatchewan

was conducted by Eldorado Mining and Refining Limited (Eldorado).3 Eldorado operated as a federal

Crown corporation beginning in 1943 and continued mining uranium – mostly in Saskatchewan – until

1982. In 1988, Eldorado merged with the provincially Crown-owned Saskatchewan Mining Development

Corporation (SMDC) to become Cameco, which is now the province’s largest uranium producer. As part

of the asset-transfer agreement, the federal government retained financial liability for environmental

impacts at the Beaverlodge sites through a newly-formed Crown corporation, Canada Eldor Inc. Through

3 The company became known as Eldorado Nuclear Limited in 1965.



a licensing agreement, Cameco became responsible for carrying out reclamation and monitoring activities

at the sites (Webster & Hockley 2013: 3).

Of the six total mine sites that have been accepted to the ICP, five of them are former uranium sites

that were operated by Eldorado at its Beaverlodge properties.4 Moreover, many of the sites that are slated

to apply for acceptance to the program are former Eldorado sites (Webster & Hockley 2013). Because the

federal government retained liability for many sites, this may have provided some impetus for the

establishment of the ICP. This is supported by the fact that, although industry may develop a framework

for relinquishment, the driver behind accepting it is, ultimately, governments (i.e. the Crown). The number

of abandoned / orphaned mine sites in Saskatchewan is also small as compared to other Canadian

jurisdictions (i.e. British Columbia, Ontario, and Quebec), which may have enabled the government’s

capacity to manage the incoming mine sites.

Furthermore, the uranium sites that have been accepted are relatively benign (Webster and Hockley

2013: 5). The gold mine site that was accepted to the ICP is also relatively small (i.e. production of

190,000 ounces over a four year mine life from 1994-98).5

5.3 Québec


In Québec, mine operators may apply for a ‘certificate of release’, which releases a company from

any further reclamation, closure, and post-closure obligations. This is provided for under Division III

(Protective Measures and Rehabilitation Measures) of the Québec Mining Act. Specifically, section 232.10

states:

The Minister may release any person from his obligations under sections 232.1 to 232.7 and issue to

him a certificate to that effect,

(1) if the Minister is satisfied that the rehabilitation and restoration work has been completed

in accordance with the rehabilitation and restoration plan approved by the Minister, and if no

sum of money is due to the Minister with respect to the performance of the work; and

(2) if the Minister is satisfied that the condition of the land affected by the mining activities no

longer poses a risk for the environment or for human health and safety and, in particular, poses

no risk of acid mine drainage.

The Minister may also release a person from the obligations set out in sections 232.1 to 232.7 and

issue a certificate to that effect if the Minister agrees to let a third person assume the obligations.

4 There are 68 additional Beaverlodge sites that have not been admitted to the program. Additionally, the gold mine site that was accepted into the program was the Contact Lake gold mine, which was operated by the SMDC. 5 The sum that was posted to cover the monitoring was CAD$30,000.



Additionally, under Section 232.12, the operator will still be responsible for any environmental

liabilities associated with the site. Specifically,

Nothing in sections 232.1 to 232.11 shall affect or restrict the application of the Environment

Quality Act (chapter Q-2).

Discussion

The above legislation has only been in force since early 2014 following amendments made to the

Québec Mining Act in late 2013 that included amendments to the process through which the operator of

a mine may be granted a certificate of release. The new legislation is stricter than the previous version of

the Mining Act, which read as follows:

232.10. The Minister may release any person from his obligations under sections 232.1 to 232.7

and issue to him a certificate to that effect,

(1) where he agrees to letting a third person assume the obligations;

(2) where, in his opinion, the rehabilitation and restoration work has been carried out in

accordance with the rehabilitation and restoration plan approved by him and no sum of money

is due to him with respect to the performance of the work and, where there are tailings, they

no longer present any risk of acid mine drainage. 1991, c. 23, s. 65.

Under the previous legislation, approximately 11 sites were relinquished to the Québec Crown

(Bienvenu 2014: personal communication). The relinquishments took place prior to 1985 and, since then,

no sites have been relinquished. In fact, no applications have been made to the Crown to do so since 1985,

likely because acceptance conditions under the legislation are not close to being met (Ibid).

In the new legislation, Section 232.10 (2) was added and is the biggest change related to

relinquishment. The language in the paragraph, specifically that, “the condition of the land affected by

the mining activities no longer poses a risk for the environment or for human health and safety”, appears

to be rather restrictive. The new legislation also stipulates that for a site to receive a certificate of release

the site “must not pose a risk of acid mine drainage” rather than just the tailings site not posing a risk, as

stipulated by the previous legislation.

It is too early to discern how the legislation will affect future applications for a certificate of release,

as the act was passed in December 2013, although it may be more difficult to obtain the certificate (Gagne

and Kazaz 2009).6 This makes the possibility of obtaining a certificate of release problematic in Québec

given that under the previous legislation, few sites actually obtained a certificate. Reference was only

6 Reference is made to a 2009 publication by lawyers of Fasken Martineau, despite the amendments to the bill being passed in late 2013. This is because the changes to the legislation regarding relinquishment are the exact same as those proposed in 2009 by the Liberal Government. Those amendments failed to pass in the National Assembly although they did pass as part of Bill 70 on 9 December 2013.



found to two sites, namely the Iron Ore Company of Canada’s Schefferville mine site and Adventure

Mining’s Lucien Beliveau gold mine site.

5.4 Ontario


Ontario provides for the return of mining lands and / or rights under Section 149 (Surrender by

Agreement) of the Ontario Mining Act. Specifically,

The Minister may refuse to accept a voluntary surrender of mining lands or mining rights under

section 183 if he or she has reasonable grounds for believing that a proponent has failed to

rehabilitate the site in accordance with a filed closure plan or, if no closure plan has been filed,

in accordance with the prescribed standards for site rehabilitation.

Furthermore, under Section 149 (1),

The Minister may accept a surrender of mining lands from a proponent on the conditions

specified by the Minister if,

(a) the project relating to the mining lands is closed out; or

(b) the project relating to the mining lands is not closed out only because it is subject to long-

term maintenance and monitoring by the proponent.

The act provides for a special purpose account that the Minister may use to conduct any

necessary rehabilitation and / or monitoring work that is required. Lastly, under Section 149

(4),

Despite subsections 7 (1) and 8 (1) and sections 12, 18, 43, and 44 of the Environmental

Protection Act, a proponent who surrenders mining lands under the section is not liable under

these provisions.

Discussion

A mine site or mine lease has yet to be surrendered to the Ontario Crown under the above provisions,

despite the provisions coming into force partially in 1996 and fully in 2001. A Ministry of Northern

Development and Mines (MNDM) review process began in 2010, although this process has yet to be

completed (NOAMI 2013: 18). However, details of a MNDM draft policy have been made available to

NOAMI. The draft policy highlights general criteria that should be met for an operator to be released from

a site / lease. Specifically,

“The surrendering [of a mining site or lease] is predicated on the fact that these lands have

been rehabilitated as per an accepted closure plan. The closure plan has as its main goals the

removal of human health and safety hazards, the removal or securing of environmental

contamination and mine wastes, the long-term protection of the environment, and the return

of lands to some productive land use. If a proponent has met the requirement of their closure



plan and is willing to compensate the Crown sufficiently for those items requiring long-term or

perpetual maintenance on the site, then the Ministry will consider the issuance of an exit

ticket.” (NOAMI 2013: 17)

The draft policy also highlighted Section 149 (4) of the act regarding “no liability” after surrender.

The draft policy states, “It is this permanent shift of environmental responsibility from the private owner

to the public that ultimately the Crown must be concerned” (NOAMI 2013: 18). This provision is evidently

a major roadblock to successful surrender of mining lands / leases. One can reasonably assume that for a

site to be surrendered, the operator would have to demonstrate with a very high level of confidence that

the risks posed by the site – to human beings, ecosystems, and the environment – are nearly zero.

Otherwise, the Crown, and ultimately taxpayers, would become liable for the potential deleterious

impacts of these risks, in contrast to the liability stipulations in other jurisdictions in Canada.

5.5 British Columbia


The British Columbia Mines Act establishes the Health, Safety, and Reclamation Code (HSR Code),

which has as one of its main components the key rehabilitation, decommissioning, and closure

requirements of mining companies. The HSR Code contains a provision for the “release of obligations”

under the Mines Act. This is the closest example of mine site relinquishment / lease surrender to the

Crown. Section 10.7.31 of the HSR Code states:

If all conditions of the act, code and permit have been fulfilled to the satisfaction of the chief

inspector and there are no on-going inspection, monitoring, mitigation or maintenance

requirements, the owner, agent or manager will be released from all further obligations under

the Mines Act.

Under provincial legislation, responsible parties (RPs) (i.e. mine owners and mine operators) are

“absolutely, retroactively, and jointly and severally liable for clean-up costs” (Packee and Bandopadhyay

2001: 184, quoting Overholt 1996). Thus, all RPs are financially responsible for all environmental

degradation following closure “regardless of whether the original mining remediation activity complied

with the laws of the day or with permits held at the time of the activity” (Ibid). Absolute liability also

precludes due diligence defenses. Given these stipulations, it follows that a closed mine in British

Columbia is never a closed mine for liability purposes (Ibid).

Discussion

No examples of a company being released from any of their environmental obligations were

uncovered as part of the research for the study. This is likely due to the policy and legislative environment

in British Columbia, which does not appear to be conducive to the practice despite a formal stipulation in

the legislation.

As stated in the legislation, a site must not have “on-going inspection, monitoring, mitigation or

maintenance requirements”. However, most, if not all mine sites will have, at the very least, some



inspection, monitoring, mitigation, and / or maintenance requirements. To be eligible, it appears that a

site would have to be a literal ‘walk-away’ site, namely one that, aside from an initial monitoring period,

would not require further attention. Current rehabilitation and closure activities may not be at a stage

whereby a walk-away scenario can be achieved except perhaps for marginally affected sites.

Furthermore, as Packee and Bandopadhyay (2001: 183-4) note, the long-term liability requirements

outlined in the previous section are the strictest among all Canadian jurisdictions. In fact, they are among

the strictest of the major mining jurisdictions in the world at the time of the survey.

5.6 Alberta


The Alberta Government introduced reclamation certificates in 1963 to promote reclamation of

privately disturbed lands and in 1978, the program was expanded to include public lands. In 2003, the

program was revised to its current form (Alberta Government 2013).

Under the provincial Environmental Protection and Enhancement Act, 2000 (EPEA, 2000), all

industrial operators are required to conserve and reclaim disturbed land and obtain a reclamation

certificate (EPEA 2000: Section 137(1)).7 There are different classes of reclamation certificates, although

in order for a site to be released or surrendered to the Crown, a site must be “certified reclaimed” (EPEA

2000: Section 144(1)) (Alberta Government 2009).

The EPEA is underpinned by the Conservation and Reclamation Regulation (CRR 1993, 2013). The CRR

defines the overarching aim of reclamation activities, namely to obtain “equivalent land capability”, which

is defined as:

“the ability of the land to support various land uses after conservation and reclamation is

similar to the ability that existed prior to an activity being conducted on the land, but that the

individual land uses will not necessarily be identical.”

The Government of Alberta – through the Alberta Energy Regulator – has also established the

Enhanced Approval Process (EAP) Integrated Standards and Guidelines, which are given effect under the

EEAP. Under the EAP, reclamation outcomes are delineated that are to be met for the issuance of a

reclamation certificate. These are:

Return disturbed land to equivalent capability;

Promote prompt re-vegetation of disturbed lands;

Re-vegetate disturbed land to target the establishment of a self-sustaining, ecologically

suitable species, integrated with the surrounding area;

Conserve soils and minimize loss of land productivity; and,

Re-establish the original landform and drainage.

7 There are a few minor exceptions to this under Section 15.1(1) of the CRR. However, these exceptions are immaterial to this study.



Given the second bullet above, and given that oil sands mining occurs primarily in complex wetland

ecosystems of boreal swamps, bogs, and peatland fens, specific wetland guidelines have also been

established by the Government of Alberta. In the Provincial Wetland Restoration Compensation Guide

(2007), restoration is defined as the “re-establishment of a naturally occurring wetland with a functioning

natural ecosystem whose characteristics are as close as possible to conditions prior to drainage or other

alteration.”

The CRR also defines the liability stipulations after the issuance of a reclamation certificate.

Specifically, industry is liable for all surface reclamation issues (e.g. topography, vegetation, soil texture,

drainage, etc.) for the first 25 years following the issuance of a certificate and industry is required to

resolve any reclamation issues that arise within that period. Once the 25-year period has expired, liability

reverts to the government, although liability for contamination issues remains with the company in

perpetuity (Alberta Government 2013).8

Lastly, reclamation certificates that have been granted are subject to amendment and / or

cancellation. Specifically, under Section 139 of the EPEA:

(1) The Director or an inspector may

(a) amend a term or condition of, add a term or condition to or delete a term or condition from

a reclamation certificate if the Director or the inspector considers it appropriate to do so,

(b) cancel a reclamation certificate issued in error,

(c) cancel a reclamation certificate where no reclamation inquiry was conducted prior to the

issuance of the certificate and the Director or the inspector is of the opinion that further work

may be necessary to conserve and reclaim the specified land to which the certificate relates, or

(d) correct a clerical error in a reclamation certificate.

(2) The Director or the inspector shall promptly give notice of any amendment, addition,

deletion or cancellation to the same persons to whom a copy of the original reclamation

certificate was given under section 145.

(3) Where a reclamation certificate is cancelled under this section, then for the purposes of this

Part it is considered never to have been issued.

Discussion

No case of a metal mine obtaining a certificate of release was uncovered as part of the research for

this study nor was an example of a coal mine site. The closest site to obtaining one is the Gregg River

Mine, although it is estimated that reclamation objectives will take another 10-15 years to complete

(Cowan 2013: 32). The greatest number of sites that have obtained a reclamation certificate are upstream

8 The relevant section of the CRR is Section 15(1-3).



oil and gas well sites9, although these have marginal reclamation and rehabilitation requirements as

compared with mining operations (see Figure 1). These sites are also administered under a separate

program.

FIGURE 1 – TYPICAL ALBERTA WELL SITE (McIntosh 2014)

In 2008, Syncrude’s Gateway Hill site – a 1.04 km2 former overburden dump – became the first oil

sands site to be certified reclaimed and issued a full reclamation certificate by the Government of Alberta.

One of the biggest challenges identified in achieving reclamation goals in Alberta – and ultimately

obtaining a reclamation certificate from the government – is that the criteria for doing so are unclear

(Purdy & Richens 2011). In response to this, the Cumulative Environmental Management Association

(CEMA), a multi-stakeholder research group based in the Regional Municipality of Wood Buffalo and

comprised of 50+ members from industry, regulatory agencies, Aboriginal communities, and non-

governmental organizations (among others), developed the Criteria and Indicators Framework for Oil

Sands Mine Reclamation Certification.

The framework outlines 16 criteria and 44 corresponding indicators that are recommended for use

in determining whether a reclamation certificate should be issued. The criteria are divided amongst three

overarching reclamation objectives, which are as follows:

Objective 1: Reclaimed landscapes are established that support natural ecosystem

functions

9 Hundreds of these sites have received the certificates.



Objective 2: Natural ecosystem functions are established on the reclaimed landscape

Objective 3: Reclaimed landscapes support an equivalent land capability appropriate to

the approved end land uses

Based on these objectives, the following criteria were agreed upon:10

TABLE 2 – CEMA PROPOSED RECLAMATION CRITERIA

CEMA PROPOSED RECLAMATION CRITERIA

1.1 The landforms are integrated within and across lease boundaries.

1.2 The landforms have a natural appearance.

1.3 The landscape and its landforms incorporate watershed features such as surface drainage, lakes and wetlands.

1.4 The landforms have geotechnical stability.

1.5 Reclamation materials are placed appropriate to the landform.

1.6 Terrestrial and aquatic vegetation common to the boreal forest is established.

2.1 The reclaimed landforms have the required water quality.

2.2 The reclaimed landforms have the required water quantity.

2.3 Nutrient cycling is established on the reclaimed landscape.

2.4 Ecosystem productivity is established on the reclaimed landscape.

2.5 Reclaimed ecosystems display characteristics of resilience to natural disturbances.

3.1 The reclaimed landscape provides for biodiversity.

3.2 The reclaimed landscape provides commercial forests.

3.3 The reclaimed landscape provides for fish and wildlife habitat.

3.4 The reclaimed landscape provides opportunities for traditional uses.

3.5 The reclaimed landscape provides opportunities for recreational uses.

According the CEMA website, the organization is a “key advisor” to the provincial and federal

governments, with a role of “producing recommendations and management frameworks pertaining to

the cumulative impact of oil sands development in northeastern Alberta, which are, once complete,

forwarded to the Provincial and Federal regulators”. It is unknown what the response is to these

recommendations and whether the Government of Alberta plans on incorporating them into the

regulatory frameworks outlined above.

Another challenge in achieving reclamation goals and reclamation certificates is the stipulation that

ecosystems are to be reclaimed to a self-sustaining state. As mentioned, oil sands mining occurs primarily

in complex wetland ecosystems of boreal swamps, bogs, and peatland fens that were formed over the

course of thousands of years and harbor a large amount of biodiversity. The challenge of restoring

peatland fens is of particular importance given the size of the losses (Rooney et al. 2011) and given the

fact that there is little to no direct precedent for restoring peatland fens (Struzik 2014, quoting Suncor

officials; Purdy & Richens 2011). Until recently, it was thought that recreating peatland fens was

10 The criteria are numbered according the numbered objective.



impossible (Struzik 2014). Pilot projects are being undertaken, which have showed promising initial

results, although estimates for wetland reclamation range between CAD$3 billion and CAD$14 billion

(Struzik 2014, quoting Foote).

5.7 Gaps in Current Practice

As evidenced by the above research, a gap in regards to mine site relinquishment in Canada is the

gap in the legislative and regulatory process. Despite all Canadian jurisdictions having de jure stipulations

for relinquishment, very few mine sites have actually been returned to the Crown.

Relevant legislation regarding mine site relinquishment oscillates between two extreme across

Canadian jurisdictions, from ‘strict’ in British Columbia to ‘lenient’ in Ontario.11 In British Columbia, for an

operator to be released from their obligations under the Mines Act, the site must not have “on-going

inspection, monitoring, mitigation or maintenance requirements”. Furthermore, all jurisdictions – with

the exception of Ontario – still stipulate that liability will continue even upon surrender of the mine site

to the Crown, usually in perpetuity. Rather, the provincial government will merely monitor the site and

carry out necessary (likely minimal) reclamation efforts whose costs have been provided for through

appropriate financial mechanisms.

Conversely, under the relevant legislation in Ontario, all liability associated with a mine site will revert

to the Crown upon the site’s relinquishment. This was acknowledged by the Ontario government itself as

a major roadblock to achieving relinquishment (Cowan 2013: 17-18).

In Alberta, where a more comprehensive legislative and policy framework is in place,12 technical gaps

exist that must be overcome before the provincial government will be in a position to accept the return

of mine sites on a larger scale. This notion can be generalized across jurisdictions. Some jurisdictions, such

as Saskatchewan, will not accept sites if active water treatment is required, for example. Another example

is Quebec, where mines must not present a risk of ARD. Thus, closure and rehabilitation practices – which

encompass the associated technologies, operational controls, and current mining methods (among many

other factors) – are likely not at a stage whereby corresponding closure scenarios are acceptable to the

risk appetite of governments such that they would be willing to take the majority of mine sites back.

Notwithstanding this, it is anticipated that the development of the standardized criteria will help to drive

the development of these technologies towards regulatory acceptance for relinquishment.

Another gap that exists is the lack of reliability of closure models / scenarios, although this is rarely

stated or recognized (Maest et al. 2005: 41). The lack of reliability is due to myriad factors, including, but

not limited to, the level of detail available for closure planning (ICMM 2006; see Figure 2), changing

regulatory requirements, and the ability (or lack thereof) to accurately capture uncertainties. On this latter

point, Goodbody (2013: 45, quoting Weeks) notes,

11 ‘Strict’ and ‘lenient’ are used loosely to describe liability stipulations. 12 To be sure, many regulatory gaps still exist, such as the development of closure and reclamation criteria that were outlined above. As mentioned, it is unknown if these criteria have been accepted and operationalized by the government, although it does not appear to be the case.



“especially in closure, where there can be pressure to make predictions for periods of time

that are far beyond what is seen in most other areas of engineering practice, there is often a

lack of understanding of the variance or error in model outputs. These may be much greater

than realised by some model users, and could make some model outputs so unreliable as to

be redundant”.

Given these difficulties, it becomes similarly difficult to accurately assess long-term closure costs,

including after a site is closed out. In turn, this affects the ability to accurately provide funding for

reclamation and closure activities. Struizk (2014, quoting Bayley) uses the Environmental Protection

Security Fund in Alberta to illustrate this. To date, the fund has US$875M in bonded assets for more than

70,000 ha of disturbed land; however, other estimates calculate the reclamation and closure costs at over

US$14B. This gap likely reduces the willingness of governments and stakeholders to accept relinquishment

on a large scale.

FIGURE 2 - STAGES OF CLOSURE PLANNING (Starke 2008)



Another gap that exists is the lack of emphasis on comprehensive, up-front closure planning activities

(i.e. closure planning early in the mine life development cycle). This includes incorporating detailed closure

planning and costs into pre-operations activities (i.e. preliminary economic assessments (PEAs), pre-

feasibility studies, detailed feasibility studies, etc.). To be sure, closure planning has become more

integrated into the early stages of mine design and development, as evidenced by the “design for closure”

approach introduced in the 1980s. However, a paradigm shift is perhaps needed towards, to borrow

Cowan’s (2013: vi) phrase, “design for relinquishment”. The development of the criteria will help to fill

this gap given that there will be a defined end that practitioners and managers can work towards; by

knowing the end goal, mine design and management can be tailored towards achieving it.

Similarly, up-front (i.e. baseline) data collection is also critical to achieving successful mine closure

and ultimately relinquishment, especially for biodiversity and ecosystem rehabilitation, which are

becoming ever-important components of mine reclamation and closure (e.g. the Albertan regulations

described above). As the CMIC / Hatch scoping study (2013: 31) notes, “achieving objectives and targets

for biodiversity in closure are dependent on baseline information and datasets collected from project pre-

development”. The report (quoting Lloyd 2002 and ICMM 2006: 30) also notes general challenges

associated with biodiversity data. Specifically,

“one of the major constraints to the effective management of biodiversity is the scarcity of existing

scientific data regarding the way biodiversity changes in response to disturbance. To date, much of

the potentially useful information from large-scale management activities taking place during

operations of a mining project has been rendered unusable due to a lack of formal experimental

design such as a lack of controls and replication, changes in techniques and technologies over time,

and a lack of basic before and after monitoring datasets”.

The sentiment of the importance of early data collection and corresponding closure planning is

echoed by Mulvey et al. (2012) in their analysis of the only mine in Australia to be successfully relinquished

to the a state government13, namely the Mary Kathleen uranium mine. Successful relinquishment was

possible for the mine,

“due to the development of a conceptual model using real data to predict the long term geological

behaviour of the mine waste, and confirming the model projections with real-time calibration

throughout the life of the mine. Consistent integration of the closure plan into mine operations was

essential. Final landform of waste rock dumps and tailings was undertaken during mine operations.”

To summarize, the biggest gaps that were uncovered fall into two general categories:

Legislative and policy framework Technical in mining, reclamation, and closure practices.

13 This was the only mine that was relinquished at the time. Since, another mine – Barrick Gold’s Timbarra mine in New South Wales – was also successfully relinquished.



5.8 Conclusion

The gaps outlined above are likely impeding the successful relinquishment of mine sites to the

respective Crown agencies in Canada. Additionally, there is currently little impetus for mine operators to

work towards a ‘walk-away’ / relinquishment scenario given that there is no clear path / course (i.e.

criteria) that can be used to achieve this aim.

Accordingly, it is anticipated that the development of the standardized criteria for mine closure will

aid in driving the regulations, technology, and corresponding management practices towards the

achievement of mine site relinquishment. The standardized criteria may not result in relinquishment

straightaway; however, it will aid in kick-starting the process towards the ensuing realization of

relinquishment.

In turn, the following closure activities can be enhanced to help achieve a walk-away / relinquishment

scenario, including but not limited to the following:

Refined regulations / legislation that facilitates relinquishment;

Greater accuracy in closure cost models;

Development of tools for early integration of closure into the mine life cycle;

Facilitating the use of passive systems for reclamation and rehabilitation, thereby

reducing longer-term management obligations; and,

Improving the understanding of biological, geochemical, geomorphological, and surface

/ sub-surface soil and water interaction impacts to better enable the re-establishment

of near-natural conditions.

6 Passive Treatment Systems for Acid Rock Drainage

6.1 Existing Systems

Overview

Systems for managing ARD are typically grouped into ‘active’ and ‘passive / semi-passive’ treatment

options. Active treatments systems for ARD are characterized as such due to the active dosing of the ARD

with an alkaline reagent such as lime, caustic soda, soda ash, or ammonia, and collecting the floc in ponds

(Skousen et al. 2005, quoting Environmental Protection Agency 1983, Skousen & Ziemkiwwicz 1996, and

Skousen et al. 2000). These systems require regular maintenance to sustain chemical supplies, power,

pumps, and the floc handling system, and are generally considered reliable and effective. Another

predominant active treatment system is the use of membranes (e.g. reverse osmosis). However, as with

active dosing regimens, high costs, power, and maintenance requirements render them “impractical for

most remote [and] abandoned mines” (Skousen et al. 2005).

A variety of passive treatment systems have been developed as an alternative to active treatment

systems. Gusek (2002) defines passive treatment as,



“a process of sequentially removing contaminants and / or acidity in a natural-looking, man-

made bio-system that capitalizes on ecological, and / or geochemical reactions coupled with

physical sequestration. The process does not require [significant] power or chemical [inputs]

after construction, and [can last] for decades with minimal human help.”

The predominant types of passive treatment systems are as follows:

Aerobic wetlands;

Alkalinity producing covers;

Anaerobic wetlands;

Anoxic limestone drains;

Bioreactors;

Limestone diversion wells;

Limestone leach beds;

Open limestone channels;

Permeable reactive barriers;

Phytoremediation.

Slag leach beds;

Vertical flow systems / SALPs / RAPs;

Water covers;

Dry and wet soil covers; and,

Synthetic barriers.

Ultimately, the choice of treatment systems – whether passive or active – will pivot on a variety of

technical factors, including, but not limited to, acidity levels, flows, the types and concentrations of metals

in the water, the rate and degree of chemical treatment needed, and water quality requirements

(Faulkner et al. 1996). Economic factors, such as prices of reagents, costs of labour, machinery, and

equipment, treatment timeframes, interest rates, and risk factors, will also determine the suitability of

the selected option. Site-specific characteristics may also preclude the use of passive treatment systems

(e.g. geographical location, topography, climate, etc.).

Most of the above treatment options are used concurrently or sequentially to achieve the desired

outcomes based on the intervening technical and economic factors. Figure 3 and Figure 4 below provide

schematic overviews of the general selection process for various passive treatment systems given various

site-specific conditions.



FIGURE 3 – GENERAL SELECTION PROCESS FOR ARD PASSIVE TREATMENT SYSTEMS (Ford 2003: 9, adapted from Hedin at al. 1994 and Skousen 2001)



FIGURE 4 – SELECTION CRITERIA FOR PASSIVE TREATMENT TECHNOLOGIES (Ibid)

Constructed Wetlands

6.1.2.1 Overview

Wetlands are composite ecological systems in which a variety of physical, chemical, microbial, and

plant-mediated processes occur that can effect significant changes in the water chemistry of mine-

impacted water through processes of oxidation, reduction, precipitation, chelation, adsorption,

complexation, sedimentation, filtration, active plant uptake and microbial mechanisms (MEND 1999: 19).

As with other passive treatment systems, these processes are designed to mimic and optimize natural

processes, namely those that occur in natural wetlands.

Wetlands can be divided into two primary types, namely aerobic and anaerobic. Metals are removed

in aerobic cells (or zones) via precipitation, chelation, and exchange reactions, whereas neutralization is

achieved in anaerobic zones by the activity of sulphate reducing bacteria (Ibid). Passive treatment systems

typically incorporate both aerobic and anaerobic zones to carry out both microbial and abiotic reactions

(Ibid).

6.1.2.2 Aerobic Wetlands

Aerobic wetlands are the simplest type of passive treatment system (Zipper et al. 2011: 3). These

wetlands, are comprised of shallow ponds that are 0.15 m to 1 m deep. They are typically planted with

various wetland plants (i.e. macrophytes), including cattails (Typha sp.), Juncus, and Scirpus sp. (Skousen

2005: 2), which translocate oxygen to the subsurface through their roots, thereby facilitating the oxidation

of metals (Zipper et al. 2011: 3). As Zipper et al. (2011: 3) note, “the aquatic plants also help to prevent

channelization of the waters flowing through the wetland, slowing water velocities and aiding solid-phase

metal removal via sedimentation.”

The primary function of aerobic wetlands is to provide sufficient residence time and aeration to allow

metal oxidation reactions and hydrolysis, which, in turn, facilitate the precipitation and physical retention



of mostly iron, aluminum, and manganese hydroxides (Skousen et al. 1998: 106). Once sufficient residence

time and aeration are allowed for, the influent ARD is drained by gravity though the wetland, thereby

progressively undergoing metal removal / neutralization (See Figure 5).

FIGURE 5 - FREE WATER SURFACE CONSTRUCTED WETLAND14

The pH and net acidity/alkalinity of the water are important because pH influences both the solubility

of metal hydroxide precipitates and the kinetics of metal oxidation and hydrolysis (GARD Guide n.d.:

Chapter 7). Thus, aerobic wetlands are generally constructed to treat mine-impacted waters that are net

alkaline.

Another key remedial process that occurs in aerobic wetlands is the removal of arsenic, which is

highly toxic even at trace levels. Typically, arsenic in mine-impacted waters originates from the oxidative

dissolution of arsenopyrite (FeAsS) that may be present in mine waste. Soluble arsenic may be removed

via absorption onto positively charged ferric iron colloids and, in theory, by the formation of scorodite

(FeAsO4). Novel strains of Thiomonas-like bacteria that oxidizes arsenic (III) to arsenic (V), have been

isolated from mine waters (Johnson & Hallberg 2005: 9, quoting Battaglia-Brunet et al. 2002 and Coupland

et al. 2003). Other trace metals that will co-precipitate with iron to some degree are cadmium, copper,

lead, and zinc.

Aerobic wetlands can also be characterized by their potential flow paths, namely surface and

subsurface flows. Treatment systems may be designed such that different cells in the system utilize

alternative flows. Figure 6 provides an illustration of these different types.

14 Retrieved from: http://www.prp.cses.vt.edu/Research_Results/SAPS.html



FIGURE 6 – CONSTRUCTED WETLAND CELLS SHOWING POTENTIAL FLOW PATHS (MEND 1999: 31)

6.1.2.3 Anaerobic Wetlands

In contrast to aerobic wetlands that are designed to maximize the effectiveness of oxidisation

reactions, anaerobic wetlands rely on the lack of oxygen and the promotion of chemical and microbial

processes to precipitate metals as well as to generate net alkalinity and biogenic sulfide (MEND 1999: 3;

Johnson & Hallberg 2005: 10). These systems rely on thick, water-permeable, and organic-rich substrates

that become anaerobic due to high biological oxygen demand (Gard Guide n.d.: Chapter 7). A layer of

limestone may be added to the bottom of the wetland or it may be mixed among the organic matter.



Limestone dissolution and the metabolic products of sulfate-reducing bacteria (e.g. Desulfovibrioa,

Desulfotomaculum, etc.) raise pH and precipitate metals as sulfides, hydroxides, and / or carbonates

(Skousen & Ziemkiewicz 2005: 3, quoting Henrot and Wieder 1990).

The most common form of sulfide reduction generates H2S and bicarbonate alkalinity. As Zipper et

al. (2005) note, sulfate-reducing bacteria utilize the oxygen that enters the anoxic environment as a

component of sulfate (SO42-) for metabolic processing of biodegradable organics.

General guidelines for construction of anaerobic wetlands suggest utilizing a 30-60 cm layer of

organic matter over a 15-30 cm bed of limestone, or placing a mixture of organic matter and limestone to

a depth of 50-100 cm. Crucially, the organic matter must be permeable and biodegradable (Zipper et al.

2005a: 5). Common animal manure from browsing animals like cows, sheep, or goats are preferred,

although wood chips, crushed limestone, plant residue, grass cuttings, hay, straw, manure, and compost

are used as well (GARD Guide n.d.: Chapter 7). Myriad innovative substrates are now being tested as part

of laboratory and bench-scale studies, including alfalfa hay, walnut / pecan shells, and mussel shells

(among many others) (Lee at al. 2014; Trumm and Ball 2014). The design depth of the water over the

substrate varies, with some designs maintaining water depths of 10-30 cm, while others are deeper (Ibid).

The sulfate-reducing bacteria (e.g. Desulfovibrioa, Desulfotomaculum, Desulfobulbus) function best

in the pH range of pH 6 to pH 9 (Skousen 1999: 109, quoting Widdle 1988), although they have limited

function down to pH 5 (Skousen 1999: 109). For treatment, optimal aerobic wetland performance is

expected when the pH is pH 6.0 or above and when the water is net alkaline (Skousen & Ziemkiewicz

2005: 6).

Figure 7 and Figure 8 show the systems in practice. The site in Figure 7 contains six cells, of which the

first three are seen. The first red pond collects the seepage from the hillside. The water is then routed

through these anaerobic cells through spillway berms. Figure 8 shows a longer, narrower system (Skousen

& Ziemkiewicz 2005).



FIGURE 7 – ANAEROBIC WETLAND TREATMENT SYSTEM (Skousen et al. 2005: 1112)

FIGURE 8 – ANAEROBIC WETLAND TREATMENT SYSTEM (Skousen et al. 2005: 1110)



6.1.2.4 Vertical Flow Wetland Systems

Vertical flow wetland (VFW) systems15 combine the treatment mechanisms of anaerobic wetlands

and ALDs in an attempt to compensate for the limitations of both (Zipper et al. 2005: 8, quoting Hendricks

1991, Duddleston et al. 1992; Kepler & McCleary 1994). In this system, water flows downward through a

layer of organic matter, then through a bed of limestone, before flowing out through a drainage system

(Skousen 1999: 117).

VFWs are similar to AWLs, although the addition of a drainage system to force the ARD into direct

contact with the alkalinity-producing substrate is what differentiates the two (Zipper et al. 2005: 8).

Furthermore, the ARD must pass vertically through the organic matter and the limestone to exit the

system through a standpipe. The associated alkalinity is generated, like anaerobic systems, through sulfate

reduction and limestone dissolution. Metal removal is also possible, mostly through precipitation in the

settling pond that receives the discharge waters.

Similar to anaerobic wetlands, VFWs are used to treat net-acidic mine waters, although they have

been shown to treat higher concentrations of metal contaminants due to the addition of a settling pond,

which facilitates the precipitation. Furthermore, due to the forced contact of the ARD with the limestone,

acid neutralization is more rapid in VFWs. Consequently, VFWs require shorter residence times and

smaller surface areas (Zipper et al. 2005: 10). Figure 9 presents a general schematic of a VFW (or SAPS).

FIGURE 9 – GENERAL SCHEMATIC OF A VERTICAL FLOW WETLAND SYSTEM16

15 These systems are also sometimes referred to as “reducing and alkalinity producing systems” (RAPS) or “successive alkalinity producing systems “SAPS”. 16 Retrieved from http://www.prp.cses.vt.edu/Research_Results/SAPS.html



Passive Bioreactors

Passive bioreactor systems rely on sulfate-reducing bacteria (SRB) – coupled with a biodegradable

carbon source – to increase pH and water alkalinity as well as to immobilize dissolved metals by

precipitating them as metal sulfides (Neculita et al. 2007a: 1-2).

Bioreactors are analogous to anaerobic wetlands in that the acidic drainage is directed / flows

through organic materials. These systems may be very small – often in one or a series of tanks / barrels –

or they may be very large (see Figure 10). The systems are particularly useful for remote mine sites and

sites with extreme weather conditions (Zagury et al. 2007: 1439-1440).

Anaerobic “wetland” systems are sometimes referred to as “compost bioreactors” given that, in

some installations, the systems are enclosed entirely below ground level and do not support any

macrophytes; thus, they are not wetlands per se (Johnson & Hallberg 2005: 9-10). Some designers

encourage using deeper waters and no vegetation at all, supposing that the translocation of oxygen to

substrates through the roots of the macrophytes hinders anoxic conditions, and thus, substrate functions

that are critical to performance (Zipper et al. 2005: 5-6).

In the last 20 years, passive bioreactors have successfully treated ARD-contaminated waters in both

pilot and full-scale projects (Neculita et al. 2007a). However, reactive mixture composition, ARD load, and

metal toxicity have limited the efficacy of some systems (Neculita et al. 2007b). Furthermore, additional

research is needed to properly assess the long-term efficacy of reactive mixtures and the associated metal

removal mechanisms (Ibid). Lastly, as Neculita et al. (2007b) note, “metal speciation and ecotoxicological

assessments of treated effluent from on-site passive bioreactors have yet to be performed”.

FIGURE 10 – SULFATE-REDUCING BIOREACTOR SYSTEM (Cavanagh et al. 2010)

Anoxic Limestone Drains

Anoxic limestone drains (ALDs) are a form of alkalinity addition for ARD that has a net acidity (MEND

1999: 7). ALDs are constructed trenches filled with high-quality, crushed limestone that is sealed under

geotechnical fabric or layer (i.e. clay) and covered with soil. Plastic is sometimes placed between the

limestone and clay to act as an additional gas barrier (GARD Guide n.d.: Chapter 7.5.2.3). As with anaerobic

wetlands, the systems rely on the exclusion of dissolved oxygen in the water; if dissolved oxygen is

present, iron and aluminum hydroxides clog the system, which will cause failure (Ford 2003: 13).



Thus, similar to anaerobic wetlands, the limestone produces bicarbonate alkalinity through

dissolution (Zipper et al. 2005: 6).

The sole function of an ALD is to convert net acidic mine-impacted water to net-alkaline water by

adding the bicarbonate alkalinity. The removal of metals is not intended because metal hydroxide

precipitation within an ALD will retard water flow and the permeability of the drain resulting in premature

failure (Skousen 1999: 114-5). This will typically occur when pH 4.5 or above is reached (Zipper et al. 2005:

7). Thus, ALDs are not a stand-alone treatment of ARD but rather form part of a series of cells (MEND

1999: 13).

The majority of ALDs that have been implemented have been used for the mine-impacted waters of

coal mines. This is also true of research surrounding ALDs (MEND 1999: 7). Furthermore, MEND (1999:

12-13) posits that ALDs may only have limited applicability to Canadian mines given the strict influent

stipulations that are required for ALDs to be effective. Specifically, dissolved oxygen, ferric iron, and

aluminum concentrations typically must be <1mg/L and sulphate concentrations typically must be below

2,000 mg/L. Given that most ARD sites in Canada do not meet these influent requirements, ALDs may only

have limited long-term application to Canadian mines. This is not to say that ALDs are less effective in a

more extreme northern climate (MEND 1999: 13), although this is a general gap in regards to passive

treatment systems (see Section 6.3.2).



FIGURE 11 – SCHEMATIC OF ANOXIC LIMESTONE DRAINS (GARD Guide n.d.: Chapter 7.5.2.3)

Open Limestone Channels

Open limestone channels (OLC) are open-air analogues to ALDs. They are open channels or ditches

with limestone placed along their sides and in the bottom of culverts, diversions, ditches, and / or stream

channels (Ford 2003: 5). Water flows down a steep slope through the limestone riprap and is conveyed to

a discharge point (Ford 2003: 6; GARD Guide n.d.: Section 7.5.2.5). Thus, these systems are employed

where ARD must be conveyed over some distance prior to or during treatment.

Alkalinity is introduced via the dissolution of the exposed limestone, which dissolves in the bottom

and side of a limestone drain. OLCs can be effective as one element of a passive treatment system,

although they are not typically relied on as a stand-alone system; rather, they usually form part of a larger

ARD treatment strategy (Zipper et al. 2005: 8, quoting Ziemkiewicz et al. 1997; Skousen et al. 2000).

Specifically, OLCs are typically useful as the stage that fulfills the requirement of conveying the ARD over

some distance.



Limestone Diversion Wells

Limestone diversion wells (LDWs) consist of a well in the form of an in-ground metal or concrete tank

that contains crushed limestone aggregate. Part of a fast-flowing stream is diverted, often via a pipeline,

into the well. The hydraulic force of the flow causes the limestone to turbulently mix and abrade into fine

particles and prevent armoring. The water flows upward and overflows the well at which point it is

diverted back into the stream.

LDWs are typically viewed as passive treatment systems, although significant maintenance is

required. Because limestone can only be added to the well in small amounts, frequent refilling is required

(Taylor et al. 2005: 19). Hopper feed systems can be installed to enable automatic refilling, which reduces

the amount of maintenance required. However, regular maintenance to remove leaves and other debris

will still be required to avoid blocking (Ibid).

Figure 12 provides a schematic overview of a LDW.

FIGURE 12 – SCHEMATIC VIEW OF A LIMESTONE DIVERSION WELL17

Limestone / Slag Leach Beds

Limestone leach beds (LLBs) consist of a cell or a series of cells that are filled with limestone to varying

degrees, and receive water that has little or no alkalinity or dissolved metals (Skousen & Ziemkiewicz 2005:

8; Black et al. 1999). The water slowly dissolves the limestone and the associated alkalinity concentration

that is generated ranges from 50 – 80 mg/L of CaCO3 (Black et al. 1999: 8), which helps to buffer streams

against acidity downstream (Skousen & Ziemkiewicz 2005: 4).

Slag leach beds (SLB) are a more recent development as compared with the other options presented

in this study. This system utilizes a bed of steel slag fines (-⅛ in.) to treat water that does not contain iron,

manganese, or aluminum (Skousen & Ziemkiewicz 2005: 4, quoting Simmons et al. 2002). The steel slag

contains high levels of alkalinity that are released into the water, with some pilot studies noting alkalinities

17 Retrieved from http://www.ei.lehigh.edu/envirosci/enviroissue/amd/links/passive4.html



in water as high as 2,000 mg/L. However, as the GARD Guide (n.d.: Section 7.5.2.7) notes, sites in which

these high alkalinities are generated must be carefully selected since water that is too alkaline can be

highly toxic to aquatic life.

Manganese oxidation beds (MOBs) are similar to limestone and slag leach beds. The MOBs support

the growth of a bacterial / algal consortium, which enables the precipitation of manganese oxides and /

or similar compounds. However, MOBs are positioned as a final step in a treatment system. This is because

they are only effective once all iron has been removed, as dissolved Fe2+ chemically reduces manganese,

which causes it to dissolve. Figure 13 below shows a LLB treatment system. Figure 14 presents a slag leach

bed system.

FIGURE 13 – LIMESTONE LEACH BED TREATMENT SYSTEM (Cavanagh et al. 2010)

FIGURE 14 – SLAG LEACH BED TREATMENT SYSTEM (Ibid)



Permeable Reactive Barriers

As Johnson and Hallberg (2005: 10) note, permeable reactive barriers (PRBs) are increasingly being

used to treat a wide range of polluted ground-waters. The systems are constructed for the reduction of

organic and inorganic contaminants, especially chlorinated solvents, fuels, heavy metals, metalloids,

nutrients, and radioactive materials (Sasaki et al. 2008: 835).

The PRBs operate on the same basic principles as compost bioreactors. However, their construction

involves digging a trench or pit in the flow path of contaminated groundwater and filling the void with

reactive materials (i.e. mixture of organic solids, limestone gravel, etc.). The void must be filled with

materials that are sufficiently permeable to allow unimpeded flow of the groundwater. Reductive

microbiological processes within the PRB generate alkalinity and remove metals as sulfides, hydroxides,

and carbonates (Johnson and Hallberg 2005: 10-11). Figure 15 below illustrates a typical PRB system

(USEPA 2014: 34).

FIGURE 15 – CROSS-SECTIONAL OF A PERMEABLE REACTIVE BARRIER18

Phytoremediation19

Phytoremediation technologies use plants to treat and / or capture contaminants in various media

Furthermore, these technologies generate minimal air emissions, water discharge, and secondary wastes,

and improve air quality by sequestering greenhouse gases (USEPA 2014: 31). There are six general

phytoremediation processes, which are summarized in the following table (adapted from Thangavel et al.

2013: 78-79).

18 Retrieved from http://www.geochem.geos.vt.edu/fluids/projects.shtml 19 These processes simultaneously occur in many of the additional passive treatment systems described above. However, they are often grouped as a separate suite of technologies in the literature.



TABLE 3 – PHYTOREMEDIATION TECHNOLOGIES

TECHNOLOGY CLUSTER DESCRIPTION

Phytostabilization

Applicable to the cleanup of both organic and inorganic contaminants Utilizes certain plant species to immobilize contaminants in the soil,

sediments, and groundwater through their absorption / accumulation onto the roots, or precipitation / immobilization within the root zone

Rhizodegradation

Alternate terms: phytostimulation, rhizosphere biodegradation, plant-assisted bioremediation

Based on the breakdown of contaminants in the soil through the bioactivity that exists in the rhizosphere

Phytodegradation

Also termed phytotransformation Refers to the uptake of organic contaminants from soil, sediments, and

water with a subsequent transformation by the plant Plants transform the organic contaminants through various internal,

metabolic processes that help catalyze degradation Contaminants are degraded in the plant with the breakdown products

subsequently stored in the vacuole or incorporated in plant tissues

Phytovitalization

Uptake / transpiration of a contaminant by a plant with the release of the contaminant or a modified form to the atmosphere

Occurs as growing trees and other plants take up water and organic contaminants

Some contaminants pass through the plants to the leaves and volatize at comparatively low concentrations

Phytoextraction

Also termed phytoaccumulation Refers to use of metal- or salt-accumulating plants that translocate and

concentrate these soil contaminants into their roots and above-ground shoots or leaves

Emphasis on “hyperaccumulators” that absorb comparatively large amounts of metals

Phytohydraulics Refers to ability of plants to capture, evaporate, and transpire water If water is able to percolate below the root zone, groundwater can be

recharged

Water Covers

As per the GARD Guide (n.d.: Section 6.6.7), the “disposal of acid generating materials below a water

cover is one of the most effective ways of limiting ARD generation” because the contact between the

minerals and dissolved oxygen is greatly limited. Specifically, the maximum concentration of dissolved

oxygen is approximately 30 times less than in the atmosphere and the diffusive transfer of oxygen in water

is approximately 10,000 times slower than in air.

Water covers can take the form of natural water bodies, which takes advantages of physically stable,

depositional environments (GARD Guide n.d.: Section 6.6.7). Engineered structures, such as tailings



storage facilities and man-made lakes, are often used for the subaqueous disposal of sulphide materials,

as are mined out pits / mine voids.

Key considerations for the use of these methods are water balance, water availability, wave action,

and the extent of rainfall / drought. Regulatory requirements may also preclude some types of disposal

mechanisms; for example, under Canadian regulations there are few instances where disposal in “fish-

bearing water bodies” is permitted.

The effectiveness of water covers may be improved by covering the waste material with a layer of

sediment or organic material, which provides additional protection against re-suspension due to the

effects of wind and waves (Johnson and Hallberg 2005: 5). Purpose-built wetland / bog covers are

examples of this system.

Water covers are in use throughout Canada, although mostly south of the 60th parallel north.

Examples include the Louvicourt Mine in Quebec, Voisey’s Bay nickel mine in Labrador, and Vale’s

Thompson Mine in Manitoba. As such, there is a need for additional research on the performance of water

covers in cold regions (MEND 2009). This is especially important given climate change considerations,

including: reduced temperatures; ice formation, scouring, and breakup; permafrost thawing; and,

changing snow cover (MEND 2011).

Dry Covers

Dry covers are typically earthen, organic, and / or synthetic materials that are placed over mine waste

materials (GARD Guide n.d.: Section 6.6.6.2). Cover materials are typically grouped into the following

categories:

Soil;

Alkaline;

Organic; and,

Synthetic.

The materials can be used in conjunction with one another; cover systems typically incorporate

several layers to help achieve the following objectives (Rykaart and Caldwell 2006), in addition to

achieving the overarching objective of stabilizing ARD and ML:

Vegetation support;

Erosion resistance;

Percolation control;

Moisture retention;

System foundation; and,

Reinforcement.

6.1.11.1 Soil Covers

Soil cover layers are constructed with natural earth materials, often including mine rock. The barriers

are typically used to achieve the following objectives (GARD Guide n.d.: Section 6.6.6.2.1):



Dust and erosion control;

Impeding oxygen and water ingress;

Contaminant release control; and,

Provision of a growth medium for vegetation.

The barriers can achieve substantial reductions in water flow through piles, although they generally

do not control ARD completely (Skousen et al. 1998: 45-6). Additionally, single soil layers have been used

in North America but are generally ineffective. Thus, soil covers are often multi-layered, with organic and

synthetic materials also used (GARD Guide n.d.: Section 6.6.6.2).

Soil store and release covers perform best in climates with high potential evaporation equal to two

to three times the precipitation.

6.1.11.2 Alkaline Covers

Alkaline cover materials (e.g. limestone) can be placed over acid-producing mine waste to increase

alkalinity, thereby providing pH control (GARD Guide n.d.: Section 6.6.6.2.2). Using alkaline materials

allows for rainfall infiltration to take up alkalinity and dissolved silicate as water seeps through the cover

material (Li et al. 2011). The alkalinity released from the covers can react with acid and metallic salts along

preferential flow pathways to create inert, precipitate-coated channels that inhibit further acid release

(Taylor et al. 2006).

As Taylor et al. (2006) note, the effectiveness of alkaline covers is limited under most climactic

conditions “as a result of the low solubility and slow dissolution rates of limestone in near-neutral

rainwater”. To be successful at more mine sites, alternative reagents will be necessary, such as fly ash,

seawater-neutralized red mud, and / or conventional caustic magnesia (Ibid). However, climactic

conditions may still preclude their use, given that system efficacy requires very high rainfall (Ibid).

6.1.11.3 Organic Covers

Mixing organic materials with acid-producing wastes helps to consume oxygen and promote metal

reduction in an anoxic environment (GARD Guide n.d.: Section 6.6.4.4). There are myriad examples of

these materials, such as pulp and paper residues, sewage sludge, bark, sawdust, sanding dust, fiberboard,

pulpwood, deinking residues, peat, compost and carbonaceous matter. Mine waste materials rich in

organic matter are also used (Ibid).

Limitations associated with organic matter include availability (especially at remotes sites), resistance

to decomposition with time, and climate (i.e. to maintain anaerobic conditions in the organic medium,

humid climates may be required). These challenges may preclude widespread application to Canadian

mine sites.

6.1.11.4 Synthetic Covers

Synthetic liners are used to encapsulate mine waste and reduce infiltration (GARD Guide n.d.: Section

6.6.6.2.5). Examples of these include:

Polyethylene (PE);

High density polyethylene (HDPE);

Chlorinated polyethylene (CPE);



Chlorosulphanated polyethylene (HYPALON);

Polyvinyl chloride (PVC);

Linear low density polyethylene (LLDPE);

Geo-synthetic clay liners (GCL); and,

Geo-membranes impregnated with bitumen.

A bedding material layer (e.g. sand) must be laid in advance to prevent puncturing by underlying

rock. A multi-layer soil cover is also required before adding the final growth substrate to prevent further

fracturing, especially if the cover soil contains a significant coarse fraction (Ibid; SRK 2013: 15).

The above covers have been shown to effectively eliminate oxygen and water ingress with relatively

low environmental risk in the long term. However, the liners have a finite life; manufacturers typically

guarantee the liners for 20-40 years and closure plans may have to allow for complete liner replacement

every 100 to 200 years (SRK 2013: 15). Synthetic liners are also one of the most expensive cover options

available.

Notwithstanding these challenges, geo-synthetic liners / covers are the least susceptible to the direct

effects of climate change, including but not limited to: changes in precipitation patterns,

evapotranspiration, and temperature as well as permafrost degradation (MEND 2011: 38).

6.2 Advancement in Technology and Development

Microbial Fuel Cells

Microbial fuel cell (MFC) architecture is being used to develop ARD fuel cells that are capable of

abiotic electricity generation. What differentiates MFCs from conventional chemical fuel cells is that the

anodes are “alive” (Lefebvre et al. 2011: 5841). The ARD fuel cells simultaneously generate electricity and

treat wastewater through the bacterial oxidation of organic matter, such as acetate, glucose, and

domestic wastewaters as well as inorganic matter (e.g. sulfides) (Cheng at al. 2007: 8149).

Researchers based at the University of Pennsylvania developed a prototype of an ARD fuel cell (see

Figure 16 and Figure 17 below) that was constructed from two plastic containers separated by an anion

exchange membrane, with carbon anodes and cathodes at either end of the chamber.

Ideally, the MFCs will be placed remotely at sites to treat water and generate electricity (e.g. for

operating pumps). Thus, the systems can be seen as a hybrid between passive and active treatment

systems.

The development of the technology is still in its infancy and is not yet at a stage for commercialisation

(Yadav 2012: 126). Nevertheless, synergistic processes such as these likely represent the way forward in

research and development.



FIGURE 16 – MICROBIAL FUEL CELL FOR ARD (American Chemical Society 2007)

FIGURE 17 – SCHEMATIC OF MICROBIAL FUEL CELL FOR ARD (Cheng et al. 200: 8149)

Gas Redox and Displacement Systems

Gas redox and displacement systems (GaRDS) is a relatively new approach to passively prevent the

formation of ARD in underground mines (Taylor and Waring 2012: 2). The approach was developed jointly

by Earth Systems and the Australian Nuclear Science and Technology Organization (ANSTO). The system

is one, if not the only, passive treatment system for ARD treatment in underground mines (Taylor et al.

2005: 31).

The system utilizes reducing gas mixtures generated by anaerobic bacterial activity to displace oxygen

without impeding drainage from the underground mine workings. The gas mixtures retard sulphide



oxidation and acid generation as well as precipitate secondary sulfides from the accumulated drainage

water (Taylor et al. 2005: 30).

The GaRDS technique has many advantages for mine operators who wish to temporarily close a mine

and retain the option of reopening the mine if metal prices increase. The systems can serve as a substitute

for the flooding of mine workings, which is the key method for limiting sulfide oxidation upon

underground mine closure. This alternative has many potential benefits, as flooding entails high costs and

the risk of catastrophic failure.

Taylor and Waring (2012: 6) outline several of the systems’ advantages:

Long term minimisation or prevention of acid drainage from underground workings;

No large scale pre-feasibility investigation required;

Rapid and low-cost to install;

Very low recurrent costs, especially relative to conventional chemical treatment systems;

Can be applied to all underground workings or portions thereof that cannot be flooded;

Only a small mass of degrading solid organic matter is required to fill (non-floodable)

airspace (i.e. adit + shaft + fracture volume) due to solid to gas conversion;

In some cases, the GaRDS approach could be combined with sewage disposal strategies for

some towns;

Re-precipitation of metal sulphides likely at some sites; and,

Performance of the system can be judged by the quality of the water emanating from the

workings (e.g. total acidity over time will decrease).

Figure 18 shows a GaRDS bioreactor that generates CO2 and CH4 gases, which displaces oxygen from

the underground mine. Figure 19 shows the installation of a low permeability well and drainage system

at the main adit opening.

FIGURE 18 – GARDS BIOREACTOR (Taylor et al. 2005: 31).



FIGURE 19 – INSTALLATION OF LOW PERMEABILITY WELL AND DRAINAGE SYSTEM (Taylor et al. 2005: 31).

Development of Innovative Substrates

The use of innovative materials as substrates in passive treatment systems is a burgeoning research

and development topic among researchers, mine operators, and governments (among others). This is

evidenced by the myriad research on the topic in the literature surrounding ARD and passive treatment

systems.

The substrates – including both chemical and organic materials – act as key sources of carbon. There

are many examples of substrates, with experimentation and development occurring with substances

ranging from wood chips and fly ash to mussel shells and crab shell chitin. Additional research regarding

the use of mine-specific wastes – including synergistically with other materials – may be beneficial to

reduce costs, optimize waste management practices, and enhance overall sustainability.

Other innovative materials that are the focus of research are zeolites (Motsi 2010), silicates to coat

sulfide minerals (Bell and Donnelly 2006: 405), microcrystalline silica (Marisco et al. 2010), and

serpentinite (Bernier 2005; Kamal and Sulaiman 2009).

Co-treatment of ARD with Municipal Waste Water

Co-treatment of ARD with municipal wastewater (MWW) is an emerging synergistic treatment

approach that blends aspects of passive ARD treatment with conventional active MMW treatment



(Strosnider et al. 2012: 26). The process offers potential savings in materials, proprietary chemicals, and

energy inputs and is a viable approach to ARD and MWW treatment in developed as well as remote,

resource-poor, and / or developing regions (Ibid: 28).

As with other passive treatment systems, the removal of acidity, metals, and sulfates is accomplished

by generating alkalinity either abiotically via passive dissolution of limestone or biotically via bacterial

sulfate reduction, which raises pH and aids in the dissolution of metals by precipitation and / or absorption

(Hughes and Gray 2013: 170). In conventional active MWW treatment using the activated sludge process,

organic compounds and nutrients are primarily removed via bacterial oxidation and assimilation

(Strosnider 2013: 26-7). Combining the two processes takes advantage of the natural alkalinity of MWW

and the absorptive properties of MWW particulates, as well as the activated sludge biomass, to remove

acidity and metals by precipitation and absorption (Ibid).

The technology is still in the research and development phase, with few systems actually constructed

to simultaneously co-treat ARD and MWW. However, small-scale testing has shown promising results

(Strosnider et al. 2012: 27). For example, one study documented the removal of aluminum, arsenic,

cadmium, iron, manganese, lead, and zinc by 99%, 88%, 98%, 99%, 14%, 88%, and 73%, respectively.

Orthophosphate has been shown to decrease below detection limits with ammonium decreasing 46%. A

near 100% reduction in total Coliforms, fecal Coliforms, E. coli, and fecal Streptococci has also been noted.

These studies have demonstrated ARD generally considered too high-strength for passive treatment could

be successfully and passively co-treated with MWW, as can the application of the conventional sludge

process (Ibid: 27-8). Strosnider et al. (2012: 28) outline multiple lines of research that should be

conducted, which, in turn, will help to enable the system to become a design option.

Recovery of Marketable Products

Active and passive treatment systems are often useful only in the context of actual treatment. A

development in the mining industry as a whole is a trend towards developing processes whereby

marketable products can be recovered from mine waste. Such products are currently able to be recovered

from passive treatment systems and can help to reduce costs.

Hedin (2012) notes that that are two conventional uses for mine drainage solids. One is iron oxide

solids have high pigmentary characteristics and thus can be used as pigments that are used in paint, stains,

concrete, and plastics.

A second general application is the use of iron-rich solids as sorbents for oxyanions, such as arsenate,

selenite, and phosphate given the high sorption capacity of iron oxides. Iron oxide is also a good sorbent

of lead, cadmium, copper, and zinc. These are particularly useful for contaminated soils, where sorption

onto the solid can decrease metals concentrations to safe levels and mitigate the need for costly soil

removal and / or disposal (Hedin 2012).

Another metal-bearing solid produced as a by-product of ARD passive treatment is a manganese-

bearing material that is used for pottery glaze (Denholm et al. 2008). The material was produced at a

former coal mine in Pennsylvania. Other industrial uses of the material are now being investigated (Ibid).



Although mine drainage iron oxide products are purer and more valuable than mined iron oxides,

they cannot match the purity of synthetically produced iron oxide (Ibid). However, volume reduction of

the mine drainage solids has not yet been explored (Ibid). Furthermore, the market for iron oxides is

already highly competitive.

A South African company – Earth Metallurgical Works – has demonstrated many innovative

possibilities in this area. The company has converted ARD-treated water and the by-products of the

treatment process into potable water (van der Merwe 2010a), stabilisers used in emulsion explosives (in

conjunction with African Explosives Limited (AEL)) (van der Merwe 2010b), and metal nitrates that are

converted into thermal salts, which can be used for storage in concentrated solar power plants (Creamer

2011). The company has also extracted ammonium sulphate, which is used as an industrial chemical (e.g.

in the vanadium industry) (Hannah 2011).

6.3 Gaps in Technology and Research

Emphasis on Treatment in Perpetuity

In 2012, MEND (2013) conducted a survey of mines producing precious and base metals, coal, and

uranium. Respectively, these mines accounted for 46%, 23%, 7%, and 5% of the mines surveyed, with the

remaining 19% classified as others. The primary purpose of the survey was to ascertain what treatment

and management options were being used in relation to ARD and sludge management. Roughly two-thirds

of the sites are based in Canada, although sites were also included from the USA (roughly 25%), the UK,

Australia, Mexico, Peru, China, South Africa, Germany, Brazil, New Zealand, and Hungary.

The survey found that the most common methods used to treat ARD were active treatment methods,

including: 1) basic neutralization through active addition of chemical / biological reagents; and, 2)

flocculation. Passive treatment systems were found to be the least utilized treatment process out of the

12 different suites of technologies. The alternative technology suites in order of their prevalence of use

are as follows:

High-density sludge;

Basic neutralization;

Other;

Reactors;

Iron sulfates;

Aeration;

Membrane separation;

Acidification;

Sludge recycle; and,

Mechanical solid / liquid separation.

In fact, the survey (2013: 5-6) found that most sites (46%) expected to treat ARD and sludge

management in perpetuity, with another 6% expecting treatment to take 50-200 years. Another 25%

expected treatment to take 10-50 years, while the least likely scenario was a 0-10 year timeframe (23%).



Thus, additional development of passive treatment systems, particularly those that strive towards walk-

away scenarios, would be beneficial to the Canadian mining industry at large.

System Performance in Northern Climates

Crucially, the design and operation of passive treatment systems must take into account seasonal

variation, especially cold climate winter conditions. This is true under conditions of a complete freeze or

a partial thaw (MEND 1999: 13).

As the GARD Guide (n.d.: Section 7.5.2.10) notes, “all biochemical and microbial reaction rates

decrease as temperatures drop”. In some instances, extreme cold temperatures can kill the treatment

organisms off altogether, thereby reducing the effectiveness of the system or causing it to fail outright

(Ford 2003: 11). This is especially true of wetland systems relying on sulfate reduction given that they are

biologically based (Ibid: 11-12).

Furthermore, snowmelt in the spring poses additional challenges for passive treatment systems given

the increased water volumes as well as the corresponding, increased trafficability of effluent runoff. This

also leads to reduced hydraulic retention time, which will inevitably reduce system effectiveness when

compared to lower flow regimes.

Some passive treatment technologies are currently better suited to harsh winter operational

conditions. For example, anoxic limestone drains and RAPs are better suited than constructed wetlands

and phytoremediation technologies. This is because the former are able to insulate the treatment against

the extremes of winter temperatures (GARD Guide n.d.: Section 7.5.2.10).

Many of the leading passive treatment technologies that have been developed have been

implemented in the Appalachia region of the United States, particularly the coal-mining states of West

Virginia and Pennsylvania. Consequently, additional applied research is required to understand how these

technologies can be adapted to suit the climatic conditions facing the Canadian mining industry.

Technology adaptation and development as it relates to ARD in other cold climates (e.g. northern Europe)

will be useful in this respect.

Lastly, system design for cold winter climates may become more important given the potential effects

of climate change (MEND 2011: 11-12), particularly the increased likelihood of more extreme seasonal

variation and weather events, which will exacerbate the challenges outlined above. Moreover, certain

systems may rely on permafrost for stability, which may reduce performance or cause them to fail. Thus,

permafrost degradation will become an increasingly important concern for system design (MEND 2011:

14).

Long-term Performance and Maintenance

As Price (2003: 5) notes, because ARD assessment and mitigation are relatively new endeavors that

have only come into being within the last few decades, there is little long-term operating experience with

respect to ARD treatment, including passive systems. In turn, there is a lack of representative data that

can be used to assess potential options. This is more true of certain systems over others; for example,



given that constructed wetlands have been utilized for a greater period of time, more information is

available as compared with biochemical reactors, for example (ITRC n.d.: Biochemical Reactors).

Consequently, additional long-term, laboratory, and field performance data are needed to address

gaps in the knowledge base. Bench testing, laboratory simulations, and small-scale (i.e. pilot) testing will

assist in filling these knowledge gaps.

Similarly, although passive treatment systems are designed with the intention of having to conduct

limited maintenance, this is often not the case. Periodic monitoring and maintenance is to be expected,

as no passive / semi-passive treatment system is wholly a ‘walk-away’ one. However, long-term

maintenance costs of passive treatment systems is a major design challenge, as many implemented

systems have experienced unanticipated maintenance activities and associated costs (Gusek 2002: 945).

Development of Innovative Substrates

The use of innovative substrates in passive treatment systems is a burgeoning research and

development topic among researchers, mine operators, and governments. Additional research is required

into how different substrates will perform under the varying climactic conditions across Canada,

particularly in areas with cold winters. A related challenge is the sourcing of local materials, including local

waste materials. In the case of steel slag leach beds, they were developed and are primarily used for ARD

treatment of coal mine-impacted water in West Virginia and Pennsylvania. Due to the proximity of steel

production activities (i.e. Pennsylvania), the process is optimized. An additional avenue for further

research would be to determine the possibility of using mine wastes as part of these systems, whether it

be processing waste or waste from another mining-related activity.

Developing synergistic processes with other waste treatment is optimal. There are many rapidly-

emerging technologies in this area. One of the most promising is the co-treatment of ARD with MWW that

was identified above.

Recovery of Marketable Products

The recovery of saleable / marketable products from mine waste is a growing trend within the mining

industry, and the extractives industry more generally. The process can help to offset remediation costs or

may actually create a revenue stream for the company. The process also helps to deal with the by-

products of ARD-treated water, which can be highly problematic themselves. Specifically, the brine and /

or sludge that is generated as part of many treatment processes will likely need to be stored in brine

ponds and / or sludge dams. This is an increasingly important concern given space limitations (See Section

6.3.8).

Currently, the process is more developed for mine waste types other than ARD materials, with one

of the most prevalent examples being the re-processing of metals from tailings storage facilities.

Additional development in this area would be beneficial to the industry and overall sustainability.



Focus on Coal Mining

Another gap that was uncovered as part of the pre-feasibility research is that a greater focus on the

passive treatment of ARD is geared towards treating ARD in waters impacted by coal mines rather than

metal mines. This is partly due to the relative scale of the ARD problem; for example, in 1995, the EPA

reported that over 80% of ARD contamination originated from abandoned underground coal workings

(Skousen and Ziemkiewicz 2005: 1). Although this report was from 20 years ago, it is anticipated that the

scale of the problem is of a similar nature.

Nevertheless, as Gusek (2009) notes, in the last two decades the scope of passive treatment has

expanded to more fully incorporate precious and base metals mines, uranium mines, and even gravel pits.

Thus, there is potential for passive treatment systems related to coal mine environments to be adapted

to other mining environments. Much knowledge, best practice, and technology development have

developed that could be transferred to these sites or, at a minimum, their applicability could be examined.

Secondary Effects

A corollary of limited long-term experience with passive treatment systems is the risk of secondary

and / or unintended effects of the systems. While a treatment process may produce a desired result – for

example, a reduction in sulfates – other, perhaps unintended, consequences may develop, such as the

formation of undesirable precipitates. This may ultimately reduce water quality (Gillow et al. 2014) and

the system may become counterproductive to meeting design goals (e.g. regulatory water quality

requirements).

There are numerous examples of passive treatment systems that have done more harm than good

(Sobolewski n.d.). This often involves trade-offs; thus, prioritizing the end-goal of a passive treatment

system is critical, which suitable design mechanisms will enable.

Space Limitations

Open spaces available for constructing passive treatment systems will likely become more restricted

(Gusek 2002: 945). This is less of a concern in Canada as compared with other jurisdictions, although

reduced environmental footprints are increasingly expected by stakeholders and regulators. Thus,

evolving system design will tend towards shrinking the treatment systems into tighter spaces. Gusek (Ibid)

posits several potential solutions including stacking, installation of the systems in underground mine voids

through boreholes, and hybrid systems that use industrial organic wastes as nutrient feed stock. This latter

solution has already become a burgeoning research topic in the literature.

7 Project Selection Workshop

7.1 Overview

A project selection workshop was held on 13 May 2014 in Vancouver that included the working group

members, the ESI Chair, and the consultant that helped prepare the pre-feasibility studies.



The primary objectives of the workshop were to assess the initial feasibility of the proposed projects

and to provide a recommendation as to which project(s) should be taken to the feasibility level. To achieve

these objectives, the workshop was structured around two main exercises:

1) Conducting a risk assessment of the projects; and,

2) Screening the projects against assessment criteria to allow for prioritization.

Feasibility study preparation and planning also took place as part of the workshop.

A risk assessment was conducted for the standardized closure criteria project. The group chose to

forego conducting a risk assessment on the passive treatment systems for ARD project as it was

determined that there were outstanding issues that were uncovered as part of the pre-feasibility research

that needed to be further addressed before an appropriate risk assessment could take place (see Section

7.4.2).

7.2 Risk Assessment

Overview

A high-level risk management exercise developed by Shepherd (1997) was used to identify, assess /

analyze, and plan for potential risks associated with the projects. An overview of these components is

presented in Figure 20.

FIGURE 20 – RISK ASSESSMENT COMPONENTS (Shepherd 1997)



The identified risks were assessed according to the likelihood of the risk and the magnitude of the

associated consequences. The risks were then placed on a likelihood-consequence matrix (presented in

Figure 21), which enabled the group to determine the scenarios that presented a high risk to impeding

project success. If a risk placed on the ‘high’ end of the matrix, a management response would be required

to control, reduce, or eliminate the risk. If a management response was not available, the project would

be deemed infeasible. The results of the risk assessment for the standardized closure criteria project are

presented in Table 4.

FIGURE 21 – LIKELIHOOD-CONSEQUENCE RISK MATRIX (Shepherd 1997)

C L O S U R E W O R K I N G G R O U P P R E - F E A S I B I L I T Y S T U D Y R E P O R T


TABLE 4 – RISK ASSESSMENT RESULTS FOR THE STANDARDIZED CLOSURE CRITERIA FOR RELINQUISHMENT

RISK LIKELIHOOD CONSEQUENCE RANKING COMMENTS

Unable to obtain stakeholder acceptance / consensus

4 3 Medium

It is highly likely that consensus will not be obtained from all stakeholders given the diverse range of stakeholders that will be impacted by the process (e.g. governments, regulatory agencies, industry, local communities, etc.). Stakeholders across the different jurisdictions will also have different expectations and risk appetites. However, it is anticipated that sufficient buy-in from a range of stakeholders will be viable given the benefits that will accrue to stakeholders once a more robust relinquishment process is implemented.

Governments oppose approach to criteria for relinquishment

3 5 High

Some governments will likely oppose the approach to the criteria given that they are risk-averse, yet without a framework to relinquish mine sites, there is a strong likelihood that abandoned mine sites will continue to accrue to the Crown. The consequence of the governments of the major mining jurisdictions opposing the approach is that relinquishment would be precluded, perhaps entirely. To mitigate this risk, government champions will be needed to advocate for the project who can aid in obtaining buy-in from other jurisdictions.

Technology risk – criteria cannot be achieved

2 4 Medium There is a low likelihood that the criteria will not be achieved due to technology risk. Rather, the criteria will be a significant driver of the development of the technology to achieve the closure objectives given that there is a defined end / goal that must be met. Though unlikely, this risk could impede project success by making relinquishment unattainable.

Unable to define acceptable criteria and risk scenarios

1 4 Low It is unlikely that the project will be unable to define acceptable criteria and risk scenarios given that the risk of not doing so will likely result in the continuing accrual of abandoned mine sites to the Crown (and ultimately the public). Additionally, criteria frameworks have previously been developed (i.e. Alberta (see Section 5.6)) that can serve as a model for criteria development.

Risk of extensive change of expectations with time

3 2 Medium It is likely that stakeholder expectations will change with time given the development of new technologies, greater understanding of environmental impacts, and more robust management practices to achieve closure objectives (among other factors). The risk can be mitigated by ensuring that the criteria evolves with time to incorporate changing expectations. Continual improvement will be a cornerstone of the criteria framework.

Unable to obtain funding / partners

1 4 Low It is anticipated that industry, consulting, and mining organizations (e.g. MAC) will support the development of the criteria. Thus, it is unlikely that the project will be unable to establish partnerships and obtain funding. Though unlikely, the lack of partners / funding could represent an unacceptable risk to the project. Thus, a primary component of future project development activities will be exploring funding opportunities and arrangements.

Unacceptable cost increase to achieve relinquishment (existing projects)

3 2 Medium For existing projects, achieving a relinquishment scenario will likely entail increased closure costs. It is likely that these costs will be unacceptable to mine operators, especially given the increasing cost pressures across the industry. However, the long-term costs and liabilities associated with mine closure will decrease. Thus, the consequences of this risk are considered low.

Unacceptable cost increase to achieve relinquishment (new projects)

3 4 Medium For new projects, it is likely that the additional costs of achieving relinquishment will be unacceptable. Specifically, some projects may not be viable – as compared with not working towards relinquishment – and may not be developed. To mitigate this risk, mine operators may continue to design for closure such that they are not required to relinquish a particular site to the Crown.

Unacceptable time to succeed (>5 years)

2 3 Low There is a low likelihood that the criteria cannot be developed within five years. Although CMIC endeavors to create a national framework, the relinquishment criteria that was developed in Alberta was developed over a 2-3 year timeframe. This process may serve as a model for the project. The consequences of this risk are moderate given that, at a minimum, the foundation of a framework will be laid.

C L O S U R E W O R K I N G G R O U P P R E - F E A S I B I L I T Y S T U D Y R E P O R T


7.3 Assessment Criteria

The project selection workshop was initially organized such that, following the risk assessments, the

projects would be screened against selection criteria, compared against each other, and prioritized based

on the results. However, because an initial risk assessment for the passive treatment for ARD project was

deemed premature – thereby deferring the project subject to further research – it was deemed

unnecessary to do so.

However, assessment criteria were formulated and ranked so as to provide direction for future

project development activities, including any feasibility work. The selection criteria are as follows (in order

of importance):

Reduces stakeholder and operations risk;

Affects all mining projects in Canada (legacy and current);

Reduces health and safety risks;

Saves time and money;

Promotes stakeholder buy-in and project sustainability;

Likelihood exists that the concept would succeed if CMIC was not involved;

Facilitates a step-change improvement in the mining business;

Encourages applications beyond mining;

Profitability of the concept; and,

Options exist for a quick win (e.g. possibly applications from other industries, availability

of a staged approach to project development).

7.4 Conclusions / Recommendations

Standardized Closure Criteria for Relinquishment

The risk assessment established that there were few risks that would prevent the project from

succeeding. For risks that did present such a scenario, management responses were developed that could

mitigate, reduce, or eliminate the risk.

Accordingly, the group made a recommendation to take the project to the feasibility level. Key

components of the feasibility-level analysis were formulated based on the results of the risk assessment.

The feasibility study will incorporate risk tracking to ensure that the identified risks are managed

prudently. The assessment criteria that were developed will also help guide the study. The major

components of the feasibility study will be organized into a terms of reference (ToR) and work plan.

It is planned that the feasibility study work will take place over 6 months and would be completed

before end 2014.



Passive Systems for ARD

The working group determined that there were outstanding issues that were uncovered as part of

the pre-feasibility research that needed to be further addressed before an appropriate risk assessment

could take place. This includes but is not limited to the following:

Lack of passive system use throughout mining operations in Canada;

Performance of the systems in winter climates, especially given sub-optimal temperatures and

spring run-off complications;

Successes and failures throughout Canada; and

Scalability.

To help delineate these issues, CMIC plans to work in conjunction with a graduate-level student under

the guidance of a professor specializing in passive systems for ARD / ML. CMIC intends to sponsor a portion

of the student’s financial requirements for the duration of their thesis work, which is planned to begin in

September 2014.

The research will enable the group to further define the initial scope of the potential project. One

option that may ensue is grouping the passive systems for ARD project with the work of the tailings

working group given the potential synergies that exist. This determination will be made after further

review.

Once the research is completed, it is anticipated that a more thorough risk assessment can be

conducted that will enable the group to make a recommendation as to whether or not the project should

be taken to the feasibility level.

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