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Ground Freezing

Cigar Lake Mine Development

Owner
Cameco Corp.
Client
Cameco Corp.
Service Performed
Site supervision services, consulting, monitoring and on-site engineering performed by senior engineer and two tunnel inspectors. Subsequent design for tunnels and junctions supporting mine development.
Commencement - Services
September 01, 2012
Completion - Services
May 01, 2020
Location
2121, 11th St W
Saskatoon, SK S7M 1J3
Canada
Geology description

Highly thermo hydraulically weathered metapelites in form of weak rock and clayey-silty-sandy soils, highly anisotropic, cut with slickensided graphitic planes.

Geology types
Hard rock
Description

Cameco's Cigar Lake is the world's highest grade uranium deposit. It is considered one of the world's most technically challenging uranium deposits to mine. The ore body and the ground around has to be bulk frozen prior to extraction of the ore using high pressure water jets. Development of the freeze/production cross-cuts takes place beneath the ore body in unstable, soil-like, highly weathered and anisotropic rock. A flexible shotcrete lining with longitudinal slots and special yielding elements together with systematic rock bolting were utilized to cope with squeezing ground conditions. Site presence and additional engineering and design efforts supported the mine development for tunnels and junctions.

Categories
Mine
Final cost
$50,000,000
Service areas
Site Supervision & CM, QA/QC
Construction methods
NATM
Special Construction techniques
Ground Freezing
Pocket excavation in unstable ground conditions
Installed yielding elements prior to spraying shotcrete
Project number
455E
Project Type
DSC
Final cost
$50 million CAD
Completion date
Ongoing

MBTA, Russia Wharf Segment, Section CC03A

Owner
Massachusetts Bay Transportation Authority
Client
Frederic R. Harris Inc.
Service Performed
NATM detailed design and site supervision during construction.
Commencement - Services
December 28, 1996
Completion - Services
December 19, 2004
Location
Boston
Boston, MD 02101
United States
Technical data

Road tunnel with 2 lanes and a lenght of 400 ft. Study into the construction of either a single tunnel or a binocular tunnel with central pier using the shotcrete support method with ground freezing pre-support to protect overlying historic building.

Geology description

Made ground, peat, glacial till (cohesive, plastic). The peat horizon undulates along the route, in places it is expected to be exposed in the top half of the proposed tunnel face.

Geology types
Soft ground
Description

The Russia Wharf segment is the last, but most challenging section of the Silverline Phase II construction for the Massachusetts Bay Transportation Authority (MBTA). The line is designed to provide a dualmode bus rapid transit connection between the central business district in South Boston to the new Convention Center. The tunnel passes diagonally under the 100 year old Russia Wharf complex, which comprises three seven-story buildings with steel frames and brick facades listed in the National Register of Historic Places. The chosen construction method was NATM in conjunction with ground freezing, for the first time in the US. Steel fibre reinforced concrete was used for temporary and permanent lining.

 

Categories
Urban Rail/Bus Stations and Tunnels
Final cost
$18,000,000
Service areas
Inspection & Maintenance, Site Supervision & CM, QA/QC, Tunnel Design & Specialities, Waterproofing & Water Control
Construction methods
NATM
Special Construction techniques
Ground Freezing
Tunneling under
Building
Groundwater control
Ground Freezing
Overview of West Cofferdam
Sheet Pile Wall
Excavation of T.H. first round
Reflectors for the monitoring
4 Bar L.G.
Short tunneling
Steel pile for underpinning
Close up of L.G.
Convergence Bolt before schotcreting
4 Bar longitudinal L.G.
Shotcrete at the face of T.H. & Bench
Installation of spiles
Spiles installed
Spiles installed
Wood piles
Installation of Spiles
Excavation of Invert
Pile Shoe Reinforcement in T.H.
L.G & Wire Mesh installed
Butt plate connection
Butt plate connection
L.G & Wire mesh, Wood piles,Pile for underpinning
Wood files
Shotcreting, Pile for Underpinning
Overview of west Cofferdam
Overview of "Russia Wharf Building"
Overview of "Russia Wharf Building"
L.G & Wire Mesh, Pile for underpinning
L.G. installation
Pile Shoe reinforcement in T.H
View of tunnel and Graphic Arts Building
L.G. & Wire Mesh at Portal Area
Wood Piles, Pile for Underpinning
Compressible Pad onto wood piles
Wood piles, piles for underpinning
Profiling in T.H using Roadheader
View of "Russia Wharf Buildings"
Wood piles, Piles for underpinning
Shotcreting
Waterproofing at Invert, Water Barriers
Installed Waterproofing, Formwork for Center Wall
Installation of Rebar Spile
Installation of Rebar Spile
L.G & Wire Mesh installed, Shotcrete Invert in T.H.
Overview Tunnel Inside
L.G. & Wire Mesh, Piles for Undpinning
L.G. & Wire Mesh, Halfenbox
Shotcrete Tunnel completed
Grouting of Spiles completed
Waterproofing installed at Invert, Halfenbox
Reinforcement of center wall
Reinforcement of a Blockout in the center wall
Pouring concrete of Invert
Invert
Welding operation
Control & Grouting Pipe, Reinjectable Hose
Control & Grouting Pipe, Fuco Hose
Top of Centerwall
Reinforcement of Shotcrete
Installation of L.G. 1st round
Excavation of 2nd half of Binocular T.
Excavation of 2nd half of Binocular T.
Shotcrete F.L., Center wall
Binocular Tunnel
Installation of spiles
Freezing Pipes
Freezing Pipes
1st half of binocular T.
1st half of binocular T.
Pile shoe reinforcement in T.H.
Plan View of the Binocular Tunnel
Tower Crane View
Tower Crane View of Russia Wharf Complex
Tower Crane View of Russia Wharf Complex
Longitudinal Section for the Binocular Tunnel
Binocular Tunnel Section
Ground Freezing Tubes and Settlement Compensation under Russia Wharf
Top Heading Excavation cutting old wooden support piles
Reinforcing and Encasing cutted wooden Piles
Reinforcement of Middlewall of Binocular Tunnel
Excavation of the second Tube of the Binocular Tunnel
Waterproofing of the Binocular Tunnel
Freezing Pipes at surface
Shoe reinforcementon timber piles
Project number
263D
Final cost
$18 million USD