Construction of the Island Falls Churchill River Powerhouse

The text and several of the photographs were taken from the Special Edition of the Northern Lights Magazine commemorating the Golden Jubilee of the HBM&S Company in 1977.


The Churchill River in northern Saskatchewan flows through a flat, gradual slope of muskeg-covered forest. Three natural reservoirs are formed: Reindeer Lake, the largest, covers an area of 2,300 square miles; the second, a number of inter-connected lakes, draws water from 29,000 square miles of the upper basin of the river; the third, Lac La Ronge, drains some 5,700 square miles of country.

The site chosen for the 45,000 h.p. hydro plant required for the development and operation of the Flin Flon ore body, was 14 miles west of the Manitoba-Saskatchewan border at Island Falls. Construction of the plant was directed by the Churchill River Power Company, Limited, a subsidiary of Hudson Bay Mining and Smelting Co., Limited. The contract for the construction and engineering work of the project was awarded to Fraser-Brace Engineering Company of Montreal in August 1928, and a program was laid out which called for construction to start during the winter of 1928-1929.

Work on the camp began in September 1928 and with the approach of winter, two problems faced the project engineers: materials, machinery and supplies had to be transported the 72 miles from Flin Flon, and a camp of sufficient size to house 23,000 tons of freight and 500 men had to be built. Initial transportation to the site became the major consideration as 500 tons of freight had to be moved across 90 miles of lakes and 20 miles of portages from Cranberry Portage, across Lake Athapapuskow, northward to Flin Flon and then to Island Falls. The magnitude of this can be understood when it is considered that this freight had to be man-handled at least 20 times between Cranberry Portage and Island Falls.

Twelve (100 h.p.) Linn tractors and 150 heavy freighting sleighs were purchased to transport the cement, steel, machinery parts and other supplies required for the powerhouse and dam.

Power necessary for construction at the site was provided by the temporary installation of two 1,250 h.p. house units at Spruce Falls on Duck Lake, 13-1/2 miles northeast of the actual power site. Construction of this temporary plant began on October 4, 1928 and it went into operation supplying 4,700,000 k.w.h. on March 28, 1929. This plant was dismantled in 1931, and the generators installed as house units at Island Falls during 1933.

Construction on the actual site got underway in May of 1929 when the ground was cleared for excavation. Rapids at the site of the main dam and powerhouse were split into two channels by an island. Water was first diverted from the south channel by two rock-filled cofferdams sheet-piled on the water face, one placed above the site of operation and one below. This permitted the excavation for the power house and sub-structure, and the sluice sections and tail-race of the main dam, and was kept de-watered until the concrete in the sub-structure of this portion of the main dam had set. Following this, the north channel was similarly blocked and the river by-passed through the undersluice.

To keep the section between the cofferdams dry during concrete pouring operations, clay was packed in front of the sheet-piled faces and the water which leaked through was removed by motor driven, 12-inch centrifugal pumps. The powerhouse sub-structure, containing the intake gates, penstocks, scroll cases, wheel pits, and draft tubes, became an integral part of the main dam and acted as foundation for the cement block super-structure. The powerhouse section occupied the south 342 feet of the main dam and provided for the installation of six generation units.

The construction of a 58.9 mile transmission line from the power plant to the Flin Flon Mine was under contract with Lang and Ross, Limited. The line consisted of 356 double-circuit galvanized steel towers on which were strung two circuits of three 266,800 cir. mil. steel-core aluminum cables. Insulators, designed for 110,000 volts, were made up of 10-inch discs with eight to a string.

Construction progressed so well that No. 1 unit began supplying power to Island Falls on June 8, 1930, and to Flin Flon on June 12, 1930. The concrete spillway dam (A Dam) was completed August 23, 1930 and the stop logs were raised to allow surplus water to cut a new channel through swamp, muskeg, and clay to Sandy Bay, re-entering the old river channel two miles downstream and forming an island on which the townsite was located.

During 1941, the flow in the Churchill River was below normal and water shortage became critical. Although water storage in Reindeer Lake was made possible by crib dams at Rocky Falls, it was necessary to build a permanent regulating dam at Whitesand Rapids, three miles below the lake outlet. One hundred men were employed on this project, which commenced early in 1942 and was completed by the end of September.

In August of 1965, it was decided to automate the power plant with the automation control centre to be located at Flin Flon. Installation was carried out through 1966 and completed by December 13, 1967. Island Falls operating personnel and their families were relocated in Flin Flon, and by March 26, 1967, camp life at the Falls had ceased. Only one building remained active as a staff house, occupied by a cook, a watchman, an operator and a maintenance man.

Construction of the temporary power house at Spruce Falls on Duck Lake, 13½ miles northeast of Island Falls.
Ready to start construction of tailrace - April 1929
Main cofferdam.
Tail-race cofferdam under construction - June 1929
The first coffer dam is beginning to close the south channel.
By July 1929, rock excavation was well underway.
Excavation for powerhouse sub-structure underway in the de-watered south channel - August 1929.
Powerhouse substructure, Unit 2, July 1929.
De-watering the tail race cofferdam.
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A-dam excavation. Notice the overhead wires for distributing power for the dinky train.
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Tailrace excavation.
Bedrock exposed for the bulwark (wing) dam construction.
West side of powerhouse.
North wall of powerhouse.
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Undersluice sections in November, 1929.
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Generator casings.
Headcover of I.P. Morris turbine.
In February 1930, the main cofferdam was demolished.
Gantry crane working on small units.
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Construction camp at M-dam, one of the soft-fill dams for containing the forebay.
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Horses and men spread fill at M-dam, September 1929.
Barge hauling sand from the sandpit, upriver. Notice the boat pushing the barge. It is the steel Gull.
Ken Dimond and Wilf Comeau working above the tailrace.
40-ton gantry crane for lifting sluicegates.
Working in the ice and snow.
Control dam under construction at Whitesand Rapids (cofferdam in background) - 1942.
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Sawing native spruce, January 1936.
Laying a wood stave pipeline to service the camp.
First crib, November 1935.
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4th Unit cofferdam.
Construction of No. 7 generator in 1959.
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Once in place, the crib is loaded with rock - June 1929
Wing cofferdam.
Tail-race cofferdam, 1929.
The dinky tracks lead past the excavation and cement work.
Excavation complete and first form under construction.
Looking downriver from above the tail race.
Dinky lines serving rock excavation for headworks.
Pit lining, Unit No. 3.
A-dam excavation.
Stripping the soil overburden for C-dam, one of the small earth-and-gravel auxiliary dams.
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Electrified machinery: the Marion shovel and dinky at work in the sluiceway excavation.
Headworks extension.
Upriver (west) side of powerhouse showing the large concrete pumping towers.
The undersluices, where Unit No. 7 was later built.
Dinky dumping blasted rock off the trestle.
Comment from Walt Leslie: Bill Wilson, from "outside", worked for Fraser-Brace. He came in to drive the Holt 30, a good tractor which would do practically as much as the 60. One time his wife was coming up to FF on the train from Dauphin to visit him at IF, when their baby died enroute. Bill left and never came back.
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Upstream side of dam in January, 1930. By this time the main building was enclosed and heated, and the machinery could be installed.
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Men hauling a muskeg island away from intakes.
We are unable to account for this small dam. The photo is dated 1931-09-28.
Howard MacIntosh walking with the two Davis children, Dick and Helen, on SF-10.
The flooding of the forebay upstream from the Plant caused a lot of damage to the shoreline and the loss of cabins.
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Walls of powerhouse constructed of cement blocks, August 1929.
Four sluice gates and three trash spillway sections nearing completion - October 26, 1929.
South bulwark under construction above headworks extension for future generator installation - then next being the installation of Unit 4 in 1935.
Completed powerhouse, with lightening arrestor tower and transmission line approach - 1929.
May, 1935 - Sullivan gas tugger hoist, which cost $7000.
Unit 4 construction, 1935
Putting up a piece of black metal on the cable to make it visible for pilots landing in the forebay.
Marion 450 trenching for the pipeline.
One-yard clam bucket.
Tailrace during unit 4 construction.
Setting the stay vanes.
Blowing up the cofferdam.

See also the M.H. Marshal General Report on construction.