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North American Tungsten Ltd’s Drystack Tailing Application ‐ Intervention

Dehcho First Nations

MV2002L2-0019 MV2014D0012

• Cantung mine is in the traditional territory of the Dehcho First

Nations

• Several communities are downstream of the Cantung mine

including Nahanni Butte and Fort Simpson

• Boat travel, fishing and hunting and other traditional harvest

activities are important for subsistence and way of life in the Dehcho

• DFN’s ultimate goal for participating in this process is to ensure that

the water quality and overall health of the Flat River is maintained.

Dehcho First Nation’s Perspective

DST Application – TSF4B, TSF7 & TSF6

TSF7 TSF4b TSF6

Size of the Drystack Tailings Facilities

TSF 4B 210,000 (tons) TSF 6 20,350,000 (tons) TSF 7 728,700 (tons) Total 21,288,700 (tons) 2014 – Total tailings – 7,348,000 tons Total proposed tailings (old tailings + new tailings) = 22,907,100 tons

Acid Rock Drainage Potential

• Majority of tailings considered potentially acid generating (sulphur

content 4% or higher)

• High neutralization potential (presence of dolomites and carbonates)
• Significant lag to the onset of acidic conditions
• If tailings do become acidic, the concentration of parameters in the

leachate increases many‐fold.

• DFN had several main concerns:
• High quantity of proposed drystack tailings for TSF 6
• Potential risks and impacts of acid generation and metal

leaching at the site

• No Closure and Reclamation Plan for the Site
• No Aquatic Effects Monitoring Program

Original Review of NATCL’s Application

DFN felt that permit/license applications constituted a significant alteration to existing operations. DFN requested that the Board screen the application and send it to an environmental assessment. MVLWB screened the application and agreed that the mine expansion was a significant alteration to the project. However, the Board decided to not move the application to EA. DFN still has concerns regarding the quantity of tailings at TSF6 and the impacts associated with acid generation.

Original Review of NATCL’s Application

DFN not opposed to Drystack Tailings Applications but has

• utstanding concerns from the Technical Sessions:
• Risks associated with ARD & Metal leaching
• Tailing Storage Facility Cover System & Process
• Application of MMER
• Flat River Floodplain & potential impacts to drystack tailings

NATCL Technical Sessions

• The tailings are potentially acid generating
• High quantity of tailings – 21.3 million tons for the proposed

tailings (TSF4B, TSF7 & TSF 6) compared to 7.3 million tons for the existing tailings

• Significant environmental concerns associated with ARD
• Difficulty in accurately predicting ARD

Risks associated with ARD & Metal Leaching

• Report is key to DFN’s concerns as it addresses:
• Model outputs of concentrations to the Flat River from TSF6
• Sensitivity analysis on climate variability and extreme events,

flushes of contact water during spring freshet and worst case ARD development.

• DFN expects that given the significant lag times NATCL will be

looking at long‐term scenarios

• Expect that NATCL will address accuracy associated with

predictions

• Report will not be completed until Jan 2016

Integrated Load Balance and Risk Assessment TSF6

• MVLWB put conditions on the Water License that TSF6 not be

constructed until DFN and other reviewers can review and discuss the Integrated Load Balance and Risk Assessment for TSF6 and can determine that there is a low potential for ARD and potential impacts to the Flat River.

• Technical sessions be held regarding ARD and impacts to the

Flat River prior to construction of TSF6.

DFN’s Recommendations – ARD Risks

• NATCL proposed to test cover designs at TSF4B to inform the

cover designs in TSF7 and TSF6.

• Detailed information is required on: the types of cover they will

be testing and the types of testing that will occur or where they will get the source material for their covers.

• DFN is supportive of this approach.

Tailing Storage Facility Cover System

The Licensee shall submit to the Board for approval, a Final Cover Design Report for TSF6, 90 days prior to construction. The design reports shall be signed and stamped by an Engineer and shall include, but are not limited to, the following:

• a. Engineering design drawings – stamped by an Engineer
• b. Issued for construction specifications;
• c. A construction quality control and quality assurance plan

NATCL’s proposed Water License Conditions TSF6

• NATCL provide an explanation of the types of testing that will occur

at TSF4B and how these elements will inform elements of construction/design of the tailings facilities and till cover for TSF7 and

• TSF6. NATCL should also provide information on where the source

material will come from.

• NATCL provide a link between testing at TSF4B and the Final Cover

Design Report.

• DFN agrees with NATCL’s proposed Water License conditions. We

also recommend that a technical session be held regarding the types and thicknesses of covers prior to the construction of TSF6 so consensus can be reached on appropriate mitigation measures.

DFN’s Recommendation – Tailing Storage Facility

• Environment Canada indicated that any runoff from the dry

stack tailings is considered effluent and must be collected and treated and if necessary, monitored and discharged through a final discharge point.

• Want more clarification from EC and NATCL on MMER

Application of MMER

• NATCL has proposed the use of a soil liner to manage seepage.
• DFN needs more clarification from EC and NATCL on seepage

from the drystack tailings and water quality concerns.

• DFN also requests mechanism in the Water License to address

seepage, soil liners and water quality concerns prior to the construction of TSF6.

Application of MMER

• TSF6 will be constructed 120m away from the Flat River.. The

closest proximity of TSF6 is about 60 meters. The flow in this areas is not expected to exceed 0.5m in depth. NATCL is proposing 0.6m thick rip‐rap blanket on the TSF slope for erosion control.

• NATCL is proposing a Flood Control and Action Plan be

included in the Water Management Plan. Will be submitted 90 days prior to construction of TSF6.

• DFN is proposing this item also be addressed in Technical sessions.

Flat River Floodplain

• DFN is working with NATCL and other partners in the

development of an AEMP and Closure and Reclamation Plan for the Site.

• We look forward to working on this processes in the future

including the development of an AEMP working group and comprehensive literature review.

Aquatic Effects Monitoring Program & Closure and Reclamation Plan

• DFN needs more clarity on the following:
• Tailings cover systems in TSF 6
• Acid rock drainage and metal leaching in TSF 6 and long‐term

risks to the Flat River

• Seepage and runoff water in TSF4b, TSF7 & TSF6 – how it will be

gathered, processed and discharged into the Flat River

Conclusion

• DFN believes that the best way to deal with unresolved issues raised

by the reviewers is to create a step‐wise process to the licensing.

• Specifically, not approving TSF6 until NATCL can provide information
• n:
• “Integrated Load Balance and Risk Assessment TSF6”
• Cover design for TSF6
• Finally, DFN requests that MVLWB facilitate a second technical session

to address concerns outlined above and any other concerns from other reviewers regarding TSF6.

Conclusion