Common Excavation Work Plan

Common Excavation Work Plan

PROJECT ID: TUNDRA MINE PHASE 2 REMEDIATION

DATE OF SUBMISSION: February 15, 2011

SUBMITTED BY: Karen Lau (TLICHO)

SUBMITTED TO: Michael Bernardin (PWGSC)

INTRODUCTION

Herein is contained the details of TLICHO’s Common Excavation Work Plan for the

Tundra Mine Phase 2 Remediation Project.

REVISION LIST

The following table tracks the process of Common Excavation Work Plan revision and

ensures that all stakeholders have the most up to date copy. The table must be updated

each time a revision is made to the document.

Figure 1 Plan Revision Table

REVISION NO.

TLICHO REVIEW DATE CROWN REVIEW

DATE SECTIONS REVISED REVISION

DISTRIBUTION DATE

1 Dwight Grabke February

14, 2011

2

3

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Table of Contents Common Excavation Work Plan ................................................................................ 1 1 Equipment ................................................................................................................... 1 2 Methodology ............................................................................................................... 5

2.1 Work to follow Erosion, Sediment and Drainage Plan ....................................... 7 2.2 Excavation Areas near Identified Hydrocarbon Contamination Areas ............... 8

2.2.1 Bulldog Lake Jetty ........................................................................................ 12 2.3 Excavation of Tailings Dams (East Lower Dam and North Dam) ................... 12 2.4 Backfill and Re-grade of Excavation Areas ...................................................... 13

3 Quantities .................................................................................................................. 13

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Common Excavation Work Plan As all waste rock on-site may be Potentially Acid Generating (PAG) rock, TLICHO will

handle all waste rock as PAG rock to prevent contamination and impacts to the

environment. An original ground survey will be performed prior to any common

excavation work.

1 Equipment The Superintendent or Project Manager will determine the specific pieces of equipment

that will be dedicated to common excavation work once the field conditions have been

assessed. The following table summarizes the fleet of equipment that will be mobilized

into Tundra Mine on the 2011 winter road. Selected pieces of equipment from this list

will be available to perform this work.

Equipment will be dedicated to common excavation work to prevent any cross

contamination of areas.

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NO Unit # EQUIPMENT DESCRIPTION EQUIPMENT PURPOSE Equipment

Weight

Number

of Loads

Equipment

fuel burn

1 LV1 White Ford

XLT

2008 Ford F350 XLT

Superduty 4x4

Site transportation. 8500 lbs driven 100 L/day

2 LV2 White Ford

XLT

2008 Ford F350 XLT

Superduty 4x4


3 LV3 White Ford

XLT

2008 Ford F350 XLT

Superduty 4x4


4 LV4 White Ford

XLT

2008 Ford F350 XLT

Superduty 4x4


5 TCP1 Light Plant Ingersoll Rand L8,

8kw@60Hz

Power supply to CMTA

treatment facilities, Back-up

power supply for camp

2300 lbs 0.25 100 L/day


8kw@60Hz




2300 lbs 0.25 100 L/day


8kw@60Hz


treatment facilities, Bac-up


2300 lbs 0.25 100 L/day


8kw@60Hz




2300 lbs 0.25 100 L/day


8kw@60Hz




2300 lbs 0.25 100 L/day


8kw@60Hz




2300 lbs 0.25 100 L/day

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11 HV4 40D Rock

Truck

40 Tonne Rock Truck

S/NCATD400EC8PS01042

Hauling of Tailings Material

and Liner Cover

73000 lbs 1.00 375 L/day

12 HV5 40D Rock

Truck

40 Tonne Rock Truck

S/NCATD400ECL8PS0106

7


and Liner Cover

73000 lbs 1.00 375 L/day

13 HV1 2007 Rock

Truck

Caterpillar 730R 26.9 Yard

Capacity, 325HP

S/N:CAT00730AB1M0108

5


and Liner Cover

51000 lbs 1.00 360 L/day

14 HV2 2007 Rock

Truck


Capacity, 325HP

S/N:CAT00730HB1M0120

4


and Liner Cover

51000 lbs 1.00 360 L/day

15 HV3 2007 Rock

Truck


Capacity, 325HP

S/N:CAT00730CB1M0122

3


and Liner Cover

51000 lbs 1.00 360 L/day

16 HV6 966 Loader Caterpillar Diesel Engine,

325 HP motor,

bucket/forklifts

Loading and off-loading

trucks; materials

management; Loading Rock

Trucks; Feed screener

50000 lbs 1.00 200 L/day

17 EX1 345CL

Excavator

2008 - 380 HP Yard

Rock/Finishing Bucket 42'

Reach

Excavation/loading of

tailings material and waste

rock into trucks; Load

Trucks

90000 lbs 1.00 500 L/day

18 EX2 345CL

Excavator

2008 - 404 HP, Long

undercarriage, C/w 6m3

bucket, 46'1" Reach


tailings material and waste

rock into trucks; Load

Trucks

90000 lbs 1.00 500 L/day

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19 EX3 EX300 LC

Hitachi

1998 - Hitachi 220 HP,

1.7m3 bucket, 32'2" reach


tailings material and final

cover material

70850 lbs 1.00 200 L/day

20 EX4 315 Excavator 2007 - Caterpillar 115 HP,

27'7" Reach, digging depth

17'3"


tailings material and final

cover material

17500 lbs 1.00 200 L/day

21 HV7 D6 Dozer 2008 - 258HP, Ripper, 12'

Blade width

Site and Tailings re-grading 47000 lbs 1.00 250 L/day

22 HV8 D6 Dozer 2008 - 258HP, Ripper, 12'

Blade width

Site and Tailings re-grading 47000 lbs 1.00 250 L/day

23 ME1 Vibroscreen 2007 SCM-55 Vibrotech

Equipment Inc

Sorting and blending

materials for final cover

27000 lbs 1.00

24 40D Rock

Truck

40 Tonne Rock Truck 73000 lbs 2.00 500 L/day

25 40D Rock

Truck

40 Tonne Rock Truck 73000 lbs 2.00 500 L/day

26 980 Loader Caterpillar Diesel Engine,

bucket/forklifts

95603 lbs 1.00 400 L/day

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2 Methodology As all waste rock on-site may be Potentially Acid Generating (PAG) rock, TLICHO will

handle all waste rock as PAG rock to prevent contamination and impacts to the

environment. Therefore, all waste rock excavated will be hauled from the excavation

area directly to its final disposal location, the tailings containment area (Lower Pond).

Waste rock will not be stockpiled anywhere else on-site.

An original ground survey will be taken prior to any excavation activities on-site. The

Departmental Representative will be notified prior to excavation activities on-site so that

they are present on-site during the work.

Excavation work will be under the supervision of the Civil Works Supervisor and the

Departmental Representative.

The areas for common excavation at Tundra Mine include waste rock at the Mill Area, at

East Lower Dam and at North Dam. The following figure shows the areas where waste

rock is identified for excavation as per the Issue for Construction drawing C8 (green

gridded areas).

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2.1 Work to follow Erosion, Sediment and Drainage Plan

All excavation work will adhere to the TLICHO Erosion, Sediment and Drainage Control

Plan to prevent sediment migration from land into the local water bodies, prevent

ponding water, and mitigate dust generation on-site during work.

To prevent sediment migration, excavations within 30 meters of a water body (ie.

Bulldog Lake) will follow the excavation procedures.

If there is a danger of a material spillage within 5 meters of a water body, it will trigger

the implementation of environmental protection supplies. The environmental protection

supplies include the following:

1. 3000 ft of silt fence

2. 1000 ft of silt curtains

3. 500 ft of sorbent booms

4. Spill Kits

Silt fence and silt curtains will be used as a preventative measure to prevent migration of

sediments into a water body. Sorbent booms and spill kits will be on hand to protect

water bodies from any uncontrolled release of contaminates. Access to shoreline

excavations by machinery should be limited to the top of the bank to minimize bank

erosion. Efforts will be made to retain riparian vegetation along the shoreline to

minimize erosion and enhance bank stability.

TLICHO’s site wide water management plan comprises of the following 5 areas where

we see a need for water management:

Controlling surface runoff from entering the excavation. TLICHO will pay

special attention to the potential of freshette impacts to the surface flow rates. The

surface runoff may be controlled utilizing surface ditches, earth dams,

Geosynthetic dams, culvert installation and pumping stations.

Controlling ground water. TLICHO will complete a preliminary drill hole with

the Minuteman drill to locate the sub-surface ground water table. The concern here

is that a high ground water table may quickly drain into the excavation creating a

significant environmental issue by contaminating water which may travel into the

adjacent ground water. In areas where the ground water table is higher than the

expected bottom of the excavation, TLICHO will implement the following

controls:

o ditching to divert ground water

o pumping to lower ground water

o locating the source and diverting the source of ground water

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Degradation of Permafrost. Any time ground is disturbed over permafrost,

especially when this changes surface or ground water characteristics, there is

significant potential for permafrost degradation. In-order to control permafrost

degradation, the ground and surface water must be properly managed. TLICHO

has a geotechnical engineer with over 20 years experience in cold regions who will

identify areas on-site where permafrost may be located. When permafrost is

encountered at an excavation site, all efforts will be made to divert any water

which may enter the excavation and propagate the degradation of permafrost. The

excavation site will be accessed as quickly as possible and recovered immediately

after work is completed. This will minimize the disturbance to the permafrost.

Precipitation Mitigation. TLICHO will not excavate during heavy rain. Areas

with a high potential for erosion will be inspected to ensure controls are in place

and maintained prior to anticipated rain events.

Plan for controlling sediments created by the excavation. TLICHO will install

silt curtains, silt fences and/or hydrocarbon booms to ensure that the excavations

will not impact the local water bodies or streams.

The water management plan will protect the environment from contaminants which will

be exposed during the excavation process as well as minimize the migration of sediments

due to water movement. When performing excavation work, a combination of the above

5 approaches will be utilized to control water, depending on what is encountered. The

construction supervisor will decide which control to implement in order to properly

manage water to prevent any sediment and erosion issues.

Dust and wind blown tailings are a concern on-site for worker health and safety during

the summer months when the roads and tailings pond are not frozen in and covered by a

layer of snow. Therefore, dust suppression will be on-going during the summer

construction season in areas of work activity. There will be a water truck on-site

dedicated to keeping dust to a minimum. It is anticipated that water will be sufficient for

dust control. If water isn’t sufficient, then we will utilize an environmentally friendly

chemical dust suppressant.

The dust suppressants that TLICHO have researched into include the following: soil-

sement from GeoEnvironmental; T.O.P from EnsSolutions; Dust Stop from Cypher

Environmental Ltd.; EnviroClear from The Amber Group. The availability, delivery time

and cost of these chemicals will play a factor in the selection process, as well as its

demonstrated effectiveness.

2.2 Excavation Areas near Identified Hydrocarbon Contamination Areas

An original ground survey will be performed prior to any common excavation work.

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There are areas identified to have hydrocarbon contamination on-site. The Civil Works

Supervisor will flag the perimeters of the areas identified to have hydrocarbon

contamination under the direction of the Departmental Representative. Prior to

excavation in these areas, workers will be trained to keep a 5 metre setback from the

hydrocarbon perimeters to prevent cross contamination. The Civil Works Supervisor will

be continually monitoring the excavations to ensure that the material excavated is free of

hydrocarbons.

A Petroflag sniffer will be on-site to aid in the identification of hydrocarbon

contaminated soil. The Civil Works Supervisor, or qualified designate will be trained to

operate the Petro flag sniffer.

If hydrocarbons are identified within any excavation, work will stop immediately and the

Departmental Representative will be notified for further instruction. Also, if we come

across buried debris in the excavation, work will stop immediately and the Departmental

Representative will be notified for further instruction.

All excavations will be sloped at a ratio of 2:1 to promote stability. This is a requirement

set within the Land Use Permit, Part C – 16. This ratio also has a built in contingency to

hold stability as the recommended slopes for most materials encountered on this site

identified for common excavation will maintain stability at a steeper slope (p. 105, Keller

& Sherar, Low-Volume Roads Engineering- Best Management Practices Field Guide).

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The Civil Works Supervisor will be continually monitoring the slopes and will consult

with the TLICHO Civil Engineer and Departmental Representative if stability is not

achieved with the current slope ratio. Work will stop immediately until a new slope is

derived.

TLICHO will excavate to the required depth as per the specifications, or as directed by

the Departmental Representative.

The following figure shows the areas identified to contain hydrocarbon excavation.

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2.2.1 Bulldog Lake Jetty

Excavation at this area will commence during open water season. The Department of

Fisheries and Ocean (DFO) will be notified and consulted on the best time to perform this

work so as to have the least impact on the fish in Bulldog Lake.

A silt curtain will be installed 3 meters all around the jetty to prevent silt migration into

Bulldog Lake. Then TLICHO will perform a fish salvage effort in the isolated area.

DFO will be consulted on best techniques for the impact fish at Bulldog Lake. During

construction, turbidity samples will be taken for continual monitoring. A threshold

turbidity will be set so that if readings surpasses the set point, work will stop immediately

and further erosion measures will be put in place to control sediment migration.

After excavation work has been deemed completed and satisfactory by the Departmental

Representative, turbidity samples will be taken on both sides of the silt curtain

installation. Once the turbidity levels are balanced between both sides, the silt curtains

will then be removed.

2.3 Excavation of Tailings Dams (East Lower Dam and North Dam)

An original ground survey will be performed prior to any common excavation work. The

Departmental Representative will be notified prior to excavation of the tailings dams.

TLICHO does not expect to excavate any part of the tailings dams until the majority of

the water in Lower Pond has been treated. Due to the topography of Lower Pond, it is

expected that the water level will decrease fastest from the South-East corner. Therefore,

the excavation can safely begin at the section of East Lower Dam between the East Upper

Dam road and the culvert at East Lower Dam. The rest of East Lower Dam and North

Dam are expected to remain in place until water has been treated to below the liner

installation elevation.

As a general rule of thumb, TLICHO will ensure that prior to the excavation of an area of

the tailings dam, it is no longer a functional barrier to retain water within that section of

Lower Pond.

Workers will be under the supervision of the Civil Works Supervisor. Workers will be

trained to stop work should they come across any buried debris or tailings in the

excavation area. The Civil Works Supervisor will be notified immediately. The

Departmental Representative will be sought for further instruction.

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2.4 Backfill and Re-grade of Excavation Areas

The Departmental Representative will be notified to perform confirmatory samples to

indicate that there is no further contamination at the excavation area. After confirmation

from the Departmental Representative and approval is granted, excavated low areas will

be backfilled with Type A material. The areas will be backfilled and graded to provide

natural drainage and to prevent ponding water at the excavated area. Where areas are

identified that do not require backfill, grading will be performed graded to provide

natural drainage and to prevent ponding water at the excavated area.

Backfill and re-grade will be performed under the supervision of the Civil Works

Supervisor and direction from the Departmental Representative.

3 Quantities There is an estimated quantity of 104,173 cubic meters of common excavation on site.

An original ground survey of the entire site will be performed prior to any excavation

work in each respective area to accurately determine areas and volumes of waste rock to

be excavated.

TLICHO recognizes the maximum excavation tolerances from the design lines as

indicated in the specification drawings is 0.3 meters, as measured from the plane of the

excavations, unless otherwise directed by the Departmental Representative.

The Departmental Representative will verify material classification for these excavation

sites.

Common Excavation Work Plan

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