GeoManitoba is pleased to offer two technical tours – one before and one after the conference.
Our first trip is an all-day tour on Sunday, September 30, 2012 – Winnipeg River Power Generation Tour – and focuses on touring a number of the hydroelectric sites of engineering interest to geotechnical practitioners along the river. Please click here for more information.
Our second trip on Wednesday, October 3, 2012 – Geology of the Manitoba Legislative Building – is a half-day (afternoon) tour of this geologically impressive building in our provincial capital. Please click here for more information.
The Winnipeg River originates in Lake of the Woods, Ontario and flows into Lake Winnipeg, ultimately terminating in Hudson Bay via the Nelson River. Located on the boundary between the Canadian Shield and the Prairies, the Winnipeg River offers spectacular fishing as well as a source of hydroelectric power for the Province of Manitoba. There are six generating stations producing a total of 583 MW on the Winnipeg River system, constructed between 1909 and 1955. Stops during the tour may include the Pointe Du Bois, Slave Falls, and Seven Sisters Generating Stations.
Pointe du Bois Generating Station, completed in 1926, is the oldest hydroelectric power plant in operation on the Winnipeg River. It is located approximately 170 km northeast of Winnipeg and spans almost one kilometer across the River. The spillway facilities at Pointe du Bois require upgrading to maintain dam safety standards and modernize the aging structures. Two new spillways consisting of a total of 12 bays will be constructed downstream of the existing structures. Approximately 750 m of zoned earthfill dam and 250 m of partial gravity concrete dam stabilized with rockfill will be constructed. Redevelopment of the Pointe du Bois Generating Station is scheduled to start in 2012, and it is expected that temporary earthworks and cofferdams will be under construction when the tour takes place.
Slave Falls Generating Station is located approximately 10 km down river from Pointe du Bois. Access to Slave Falls is via a private road from Pointe du Bois. The name Slave Falls was derived from an Indian legend, in which an Indian maiden, in her attempt to escape the warrior who enslaved her, paddled her frail canoe over the falls, to death – and freedom. Those powerful falls and the natural island, which divides the river at Slave, made it ideal for a power plant. By using the island’s granite base as a foundation, the builders saved huge sums of money, earning it the nickname “Million Dollar Island”.
Seven Sisters Generating Station is the largest hydroelectric generating station on the Winnipeg River, with a capacity of 165 megawatts. Research by the University of Manitoba and Manitoba Hydro has been completed at the site to investigate instability issues related to the water-retaining dykes arising since the dykes were heightened in the late 1940s. Results suggest that time- and location-dependent depletion of gypsum cementation bonds caused by seepage beneath the dykes has increased the brittleness and anisotropy and reduced stability with time.
The Manitoba Legislative Building, located in downtown Winnipeg, was completed in 1920 on 12 hectares of landscaped grounds. This half-day trip will expose participants to the building materials and geological setting of the Manitoba Legislative Building.
Resting atop the central dome of the Legislative Building is Manitoba’s infamous Golden Boy, a 5.25 m high bronze figure sculpted in France during the First World War. The Golden Boy is modeled after Mercury, the Roman god of trade, profit, and commerce. In the 1940’s the figure was painted gold, and in 1951 it was gilded in 24k gold. Many other figures can be found on the exterior and interior of the building, including 2 sphinxes, 16 lion’s heads, and two life-size North American bison at the base of the Grand Staircase.
The Grand Staircase inside the Manitoba Legislative Building
Dimension stones decorate the bearing walls, floors and stairways of the Manitoba Legislative Building. Each type of stone has its own decorative characteristics and each records geologic processes at different times in Earth’s history. The dimension stones used throughout the building consist of marble, limestone, and granite. The majority of the stones are from sources within Canada and the United States, although a significant portion of marble was imported from Italy. By volume, the largest source of dimension stone used for the Manitoba Legislative Building is Tyndall Stone from Manitoba. This limestone can be seen throughout the buildings’ interior and exterior and is known for its characteristic mottling from dolomitized burrows and its diverse fossils.
Other materials used in the construction of the Manitoba Legislative Building include terrazzo, construction aggregate, and brick. The terrazzo was comprised of 85% marble chips (from construction waste) in a specified proportion of marble types, and 15% interstitial cement. Construction aggregate was brought in by rail from Bird’s Hill, approximately 10 km northeast of Winnipeg. Bird’s Hill is an esker-delta complex formed approximately 12,000 years ago as the glaciers retreated. Approximately ten million bricks were used in the construction of the Manitoba Legislative Building. The bricks, both buff-coloured and red, were manufactured in Manitoba from local materials.
Examples of the diverse fossils in Tyndall Stone at the Manitoba Legislative building;
a to d are on exterior surfaces; e is at the top of the Grand Staircase.
a) Receptaculitid Fisherites, transverse section; coin diameter is 19 mm.
b)High-spired gastropod (snail); coin diameter is 19 mm.
c) Vertical section of receptaculitid (R) encrusted by tabulate coral Protrochiscolithus (P).
d) Sponge (lower centre) with the chain tabulate coral Manipora (upper left); coin diameter is 26 mm.
e)Vertical section through colony of the rugose coral Crenulites, showing distinct cyclic banding that probably represents annual growth bands (arrowed).
(Taken from: W.C.Brisbain, G. Young, and J. Young. 2005. Geology of the Parliament Buildings 5: Geology of the Manitoba Legislative Building. Geoscience Canada, Vol. 32, No. 4).