Ontario Hydro, established in 1906 as the Hydro-Electric Power Commission of Ontario, was a publicly owned electricity utility in the Province of Ontario. It was formed to build transmission lines to supply municipal utilities with electricity generated by private companies already operating at Niagara Falls, and soon developed its own generation resources by buying private generation stations and becoming a major designer and builder of new stations. As most of the readily developed hydroelectric sites became exploited, the corporation expanded into building coal-fired generation and then nuclear-powered facilities. Renamed as "Ontario Hydro" in 1974, by the 1990s it had become one of the largest, fully integrated electricity corporations in North America.
A one-dimensional analytical model has been developed to describe the compressive behaviour of clay-based shaft backfills under large hydraulic loads. The analytical model has been calibrated with results from a compression test on a partially saturated swelling clay backfill mix in the high-pressure compression cell constructed at Ontario Hydro.
Juvenile brook trout, Salvelinus fontinalis, were maintained in water of pH 5.3 or 6.5 and calcium concentrations of 5 or 40 mg/L to determine the effects of these factors on fish growth and calcium dynamics. Growth rates varied more than twofold and were significantly reduced by both low ambient calcium concentration and low pH. In contrast, calcium dynamics of the fish were significantly affected by calcium concentration but not pH. Brook trout in low-calcium water retained less labeled dietary calcium and deposited less labeled calcium in axial skeleton and visceral tissues than fish in high-calcium water. Calcium concentrations of the skin and fins were slightly but significantly reduced among fish in low-calcium water, but neither pH nor ambient calcium concentration significantly affected ash content or calcium concentration of axial skeleton and visceral tissues of experimental fish.
The paper describes research to evaluate permeability and the microstructure of mortars containing fly ash as a partial replacement for cement. The replacement levels of cement by fly ash were 35 and 50% by volume and 50% by weight; effectiveness of mortars made with four types of fly ash at two water/cement ratios, 0.47 and 0.65, were assessed. Three types of permeability measurements were made: (a) water permeability, (b) oxygen permeability and (c) permeability to chloride ion by the 6-hour rapid permeability test. Measurements were performed at 7, 28 and 160 days age. Strength gain in the mortar mixes was also monitored. In an attempt to explain trends observed in permeability, the pore structures of oven-dried and solventexchanged specimens were examined by mercury porosimetry. Mortars manufactured with fly ash displayed superior engineering properties when compared to the control mortars. Significant correlations were found among measurements of permeability by water, oxygen and chloride ion. Relationships were also observed between permeability and some microstructural indicators, especially the volume of mercury intruded up to a pressure of 41 MPa (6000 psi).
In July/August 1981 and February/March 1982 we sampled water for isotope analysis from water-bearing fractures of two mines in Elliot Lake. Permission for sampling was given to Ontario Hydro by Denison Mines Ltd and Rio Algom Ltd, Quirke Mine in conjunction with the CANMET Mine Safety Tests. The purpose of the investigation was to find out whether there is a relationship between the water present in some fractures in a deep mine and the shallow groundwater in the far-field of the mine. The investigation was done in co-operation with University of Waterloo.
