Camp Construction

8/7/2019 Camp Construction

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M T . M I L L I G A N C O P P E R - G O L D P R O J E C TE N V I R O N M E N T A L A S S E S S M E N T

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VE5156401 - Volume 3 Project Description & Planning July 2008 Volume 3 Page 3-221

3.8 CONSTRUCTION PHASE ACTIVITIES

Construction of the Mt. Milligan mine is anticipated to take about 30 months. The project willinvolve a Construction Management approach led by the construction management

members of Terrane’s Project Management team. Contracts will be prepared and issued for

service contracts including detailed engineering and construction services. The construction

contract work packages prepared by engineering will be assembled into contracts and

issued for competitive bidding.

More detail on the project execution plan is in Appendix J.

3.8.1 Construction Camp

About 700 people will be employed (direct and contractor) during construction of theMt. Milligan mine. A temporary camp will be provided for workers, with the exception of the

mine crews involved in pit stripping, during construction as shown in Figure 3.8-1. Mine

crews will commute daily from Fort St. James to the site when they arrive in the fall of 2010.

The camp will be a pre-fabricated, modular structure with 711 single occupancy rooms and

associated facilities including a dormitory building, kitchen, recreation complex,

administration complex, sewage treatment, and potable water system.

The structure will be designed with peaked roofs to handle the high snow loads in this

location. The camp will be dismantled and removed at the end of the construction period.

The mine will not accommodate casual visitors. Only people with business at the mine will

be permitted to travel to the Mt. Milligan Mine site. Most crews will work a single 12-hour

day-shift. However mine pre-strip and tailing dam construction is expected to occur

continuously given the large volume of material that must be moved starting mid-2010.

A shift comprising two 12-hour periods will be established for those crews. Mine equipment

operators will be full-time Terrane employees. The will be involved in pit stripping and

Tailings Storage Facility (TSF) construction and will travel to Fort St. James on a daily basis

and will not stay at the construction camp.

The relatively few night shift staff (security and contractor TSF construction crews during

2011) will be housed in the bottom level of the furthest southwest trailer to reduce noise

levels during their day time sleep period.

The 12-hour shifts will restrict available free time. This together with limited road access

outside the immediate mine area, normal mining operation hazards, rugged surrounding

terrain, cold and wet climate and fish and wildlife protection objectives support the mine’s

policy of discouraging employees from exploring areas adjacent to the mine during their time

off. All personnel will be required to leave the construction camp and return to their

permanent residence during their off time.



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3.8.2 Construction Sequence and Water Management

The water management concepts during construction are shown in Figures 3.8-2 through to3.8-4 and are discussed below together with the construction sequence.

3.8.2.1 Construction in 2009

The major activities in the first year of construction include:

• establish the construction camp and offices

• upgrade the access road to the site and selected site roads

• establish the site water management system

• construct the Meadows Creek Water Supply Pond (MCWSP) and pump station and south

starter tailing dam and King Richard Creek basin liner

• commence construction of the power line from the Kennedy substation to the site

Components of the site construction activities with emphasis on water management are

summarized below:

1. establish access road to site including upgrading road and bridges

2. establish construction camp and offices:

• establish sumps and silt fences and construct diversion ditches around construction

camp/office area; place temporary erosion protection mats and rock as required in

erodible areas of the diverson ditches; terminate the diversion ditches in surficial

sands and alluvials where possible

• clear and grub, strip topsoil and level site and erect construction camp and office

facilities

• drill potable water wells and connect water distribution system

• establish camp generator, electrical distribution system and fuel tank (double lined)

• install sewage collection pipelines and sewage treatment plant and construct

temporary treated sewage holding pond within TSF basin

• establish refuse collection and recycle system, install refuse incinerator and construct

landfill using a manufactured liner within till area of West Separator Berm laydownarea

3. establish site access roads to MCWSP, dam at King Richard Creek and processed sand

and gravel borrow area in esker field near north tailing dam



MT. MILLIGAN PROJECT

WATER MANAGEMENT GENERAL ARRANGEMENT PLAN

STAGE 1A (2009) CONFIGURATION

FIGURE 3.8-2VE5156401 AMEC-BBY

WMAP-1A.dwg June23,2008

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STAGE 1B (2010) CONFIGURATION


WMAP-1B.dwg June23,2008

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STAGE 1C (2011) CONFIGURATION


WMAP-1C.dwg June23,2008

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4. establish surface water management system consisting of:

• upslope diverson ditch for borrow areas

• collection ditch and exfiltration pond for the processed sand and gravel area

• coffer dam and diversion pipeline for Meadows Creek including sediment control (e.g.,

place geotextile sock around diversion inlet and outlet to remove any suspended

solids created by construction of the inlet sump and coffer dam)

• coffer dam for upper King Richard Creek

• internal coffer dam and construction water holding pond in a natural depression within

MCWSP

• sump below Meadows Creek dam location with pump to the construction water

holding pond

• sediment sump downstream of south starter dam on lower King Richard Creek• contingency flocculent addition system for MCWSP

5. clear and grub, strip topsoil and construct MCWSP and install liner and pump station

6. remove the Meadows Creek coffer dam and diversion pipeline when no longer required

7. clear and grub, strip topsoil and construct south starter dam and King Richard Creek

basin liner

8. install recycle pump in seepage recovery pond (converted sediment sump) below south

starter dam

9. clear and grub, strip topsoil, level plantsite and excavate foundation material under mill;

replace with engineered (sized and compacted) fill; any drainage from this area will flow

into the pond established behind the completed south starter dam

10. construct collection ditch on south side of construction camp leading to the pond behind

the south starter dam

The civil works (MCWSP) and south starter dam) must be completed during the dry summer

and early fall to ensure optimum compaction of till dam cores and liners.

During construction of the MCWSP dam, the water would be collected in the sump

immediately downstream of the dam footprint and pumped back to the construction water

holding pond built in a natural depression in the MCWSP basin, augmented by a small coffer

dam.

The construction water holding pond would have about 100,000 m3 capacity. The average

precipitation for July and August is 118 mm. For the 44 ha MCWSP basin this precipitation

represents about 52,000 m3 runoff neglecting evaporation and infiltration. Therefore no

discharge is expected from the construction water holding pond until the MCWSP dam is




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completed. After the dam is constructed, the construction water pond could be emptied into

the MCWSP.

The diversion pipe for Meadows Creek would be left in place until water quality was

acceptable. The capacity of the MCWSP is 2.6 Mm3. The total mean flow of Meadows

Creek from July to October inclusive is 1.4 Mm3, therefore, a discharge is not expected from

the water supply pond during 2009 until the South starter TSF is constructed, especially with

the Meadows Creek diversion pipeline in place. Once the south starter dam is constructed,

excess water will be pumped from the MCWSP to prevent an overflow of sediment laden

water.

With the above construction plan, no surface discharge of contact water associated with the

major civil works is expected. The only releases expected are via exfiltration from the ponds

and ditches constructed around the processed sand and gravel area and possibly the

construction camp area.

A flocculent addition system will be established as a contingency on the inflow to the

MCWSP in the unlikely event it is required while the south starter dam and King Richard

basin liner are being constructed. The water supply pond would be used as a settling pond

until the pump system was established. The pond has a length to width ratio of about 4:1

which is reasonable to reduce short-circuiting. Results of testing candidate flocculents are in

Appendix K.


Construction in 2010 will involve the plant site buildings and associated infrastructure,

explosives plant, concentrate load-out facility (near Fort St. James), and the fire water

system. The south starter TSF dam will be raised. In addition, stripping the open pit will

begin.

A batch cement plant will be established northeast of the construction camp.

Drainage from the plant site construction activities including the batch cement plant will flow

to the TSF pond by gravity behind the south starter dam where the water will be retained for

mill start-up. A collection ditch will be constructed below the open pit stripping area and

water drained by gravity to the TSF pond. A pump in the seepage collection pond below the

south starter dam will return construction water from that area to the TSF.

As with 2009, no surface discharge is expected from the construction activities during 2010.

The contingency flocculent addition system for the MCWSP is not required in 2010 as pumps

will be in place to return water from the water supply pond if required. Clean upstream

Meadows Creek water would discharge through the MCWSP to lower Meadows Creek and

Rainbow Creek.




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The only release expected during 2010 may be from the exfiltration pond below the sand and

gravel processing area near the north dam. The pond will be equipped with a pump and the

water pumped to the pond behind the south starter dam if required.

In the fall of 2010, all the construction water collection ditches and exfiltration ponds will be

constructed below the southeast, northeast, and north dams in preparation for construction of

these dams in 2011. Ditches and ponds will be constructed in the top 5 m of alluvial to allow

exfiltration of water that contacts construction areas. Pumps will be installed in the ponds to

transfer water to behind the south starter dam constructed on King Richard Creek.

A portion of the southeast starter dam might be constructed in the early fall of 2010

depending upon mine equipment availability.

Upon delivery and erection of the major mining units, pre-production mining will be carried

out by the Owner’s crews during late 2010. Run-of-mine waste materials will be provided for

the construction of the TSF tailing embankment. Bench pioneering and preparation activities

will proceed in advance of ramping up to full scale production.

The delivery of waste material from the open pit to the tailing embankment area has been

coordinated with the staging of the embankment crest elevation.

Clearing at the open pit and the King Richard Creek TSF during the pre-production period

has been estimated at approximately 560 ha. On-going additional clearing will be required as

the open pit and waste storage facilities are expanded and the haul roads are extended.

In advance of road building, a contractor will log, clear and grub the roads from the truckshop area to the MBX/66 pit areas. After the arrival and assembly of the partial support mine

equipment fleet (track and RT dozers, small front end loader, graders, small haul truck, water

truck and rock drill), 4.8 km of haul roads will be constructed by the mine crew. Permanent

roads will be constructed to the following areas: primary crusher, truck shop, waste dumps,

and TSF embankments.


In 2011, the contractor will continue logging, clearing, and grubbing, and the mine crew will

continue road building activities for an overall total of 7.2 km.

The southeast, northeast, and a portion of the north dam TSF starter dams and causeway

will be constructed. Water collected during construction of the tailing starter dams will either

exfiltrate or be collected and pumped from the recovery ponds to the pond behind the south

starter dam.

After all the starter tailing dams are constructed, the downslope collection ditches and ponds

will be excavated to the underlying low permeability till layer with the downslope sides lined




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with impermeable till as required. Therefore, these ditches and ponds systems will serve as

TSF seepage and dam shell runoff/seepage collection and pump back systems during mine

operations.

Construction of all mine facilities including the mill, warehouse, truck shop, and crusher will

be completed by the end of 2011. Commissioning of the facilities will begin in December

2011.

3.8.3 Construction Traffic

About 80,000 t of equipment and materials will be shipped to the site over approximately 30

months of construction based on experience with similar sized mine projects. This will

include fuel (about 13,000 t over the construction period). At about 20 t per load, this

represents about 4000 heavy loads.

Table 3.8-1 provides an estimate of road traffic during construction. The table shows the

number of return trips. Therefore, the number of pieces of equipment on the road is double

the values shown. Demobilization of contractor’s equipment can be managed by using a

back haul, so that travel is included in the table. The number of light vehicle return trips is

also shown in the table.

Arriving trucks will be unloaded and shipped out each day.

Table 3.8-1: Construction Traffic

Heavy Loads

PeriodNumber

of MonthsNumberof Days

AverageNumberof Loads

LoadsMoved

TonnesMoved Peak/Day

Average LightTraffic

Year 1

Jan - May 5 30 2 300 6,000 2 3

Jun - Sept 4 30 6 720 14,400 8 6

Oct - Dec 3 30 4 360 7,200 5 6

Total 1,380 27,600

Year 2

Jan – May 5 30 2 300 6,000 4 5

Jun – Sept 4 30 7 840 16,800 8 10

Oct – Dec 3 30 5 450 9,000 5 8

Total 1,590 31,800

Year 3

Jan – May 5 30 2 300 6,000 4 5

Jun – Sept 4 30 4 480 9,600 6 10

Oct – Dec 3 30 1 90 1,800 3 6

Total 870 17,400

Grand Total 3,840 76,800

Notes: Total tonnage to move - 80,000 tonnes. Number of loads - 4,000 loads. Average size of load - 20 tonnes.

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