My father was in construction, that's what they do. If the sand or gravel is clean, why not. When they dig the foundation for high-rises, they grind the rocks and even the bedrock into aggregate. They create mounds of aggregate for their own concrete foundations. They even grind old sidewalk concrete to be recycled into new concrete aggregate.
There absolutely are. And they're usually more expensive than the EPBM-type machines that need to be used in Toronto.
which is only 3.3m a week for those interested
It's two bores, so 1100 metres of tunnel in total.
If I remember correctly from TYSSE, you could advance a ring length (maybe 1.2m) in 1-2 hours, so maybe 5-7 in a shift.
Are you referring to the TBM progression?
The one built with rings.
It's an interesting part of the city - the area to the north developed much earlier than than the valley which came as part of Smythe's redevelopment of his gravel yard depicted in @W. K. Lis's earlier post (and gave the area its name - Rockcliffe-Smythe):
Another thing that was once in the area but is just out of view in your image is the dumping area the TTC had just next to Avon Loop (at Rogers Road and Weston). It was accessed from a spur track off of the Weston Streetcar and I believe the TTC dumped ash (among other things) from their power plants there (they used to do this at a dumping site at Fleet and Angelique Streets). This dump was active until 1960 and today is the site of St.Maria Separate School. An interesting thing about this spur was it was unpowered so work cars going to and from it would have what was essentially an extension cord attached to their trolley poles linking them to the main line power.
Much of that housing of today in that area is in a floodplain. The city continues to get complaints about basement flooding and worse from downpours in the spring, summer, and fall. Hurricane Hazel (the storm, not the former Mississauga Mayor) flooded Eglinton Flats and depositing fresh silt, hence no housing.
Jane Park Plaza (Jane Street & Alliance Avenue) is not NOW in a floodplain because they raised the plaza up onto a berm to be ABOVE the floodplain. Those industrial lots would also have to be raised up onto a berm. However, doing so could create a "dam", making the possible flood waters upstream higher. Hence, the opposition from the neighbourhood.