The NorthConnex project has been approved and there are a myriad of politicians running around patting each other on the backs, saying what a fine piece of engineering this tunnel will be.
They are correct, it will be a fine piece of engineering, but I have some concerns about the disruption and environmental impact the works will have on our community, while it is being built.
NorthConnex will link the M1 Pacific Motorway at Wahroonga to the M2 Motorway at the Pennant Hills Road interchange at West Pennant Hills.
NorthConnex will provide wide ranging benefits for the community including improvements to local air quality and road safety, with around 5000 fewer heavy vehicles on Pennant Hills Road each day.
The works on the tunnel are due to begin in Feb 2015 and will take approximately four years to complete, with the main tunnelling work taking two years and nine months.
It has been called “A game changer” by some politicians and they are right. Once complete, driving from the M1 to the M2 will be a simple five minute drive, rather than half an hour of frustration as you pass 21 sets of traffic lights.
But, to build the tunnel, approximately 4.5 million cubic metres of rock will be dug out and carted away. That’s a lot of rock.
It has been proposed by NorthConnex to dump some of that spoil in to Hornsby Quarry, filling-in that disused quarry. Filling-in a disused quarry is a good thing.
According to NorthConnex, Hornsby Quarry has a capacity for up to 3.3million cubic metres of spoil.
If Hornsby Quarry took 3.3 million cubic metres of spoil during the 2 years and 9 months of tunnelling, that would be over 1,200 trucks per day, 365 days per year, which would not simply disrupt traffic in the area; it would bring it to a complete stand still.
For those people dragging out their pocket calculators, I have assumed that the truck is 25 tonnes in capacity and can carry 25 cubic metres of spoil.
NorthConnex have said that the majority of spoil movements would be during the day where practical, but would consider moving spoil 24 hours per day, seven days per week during peak construction periods. Yes, it could be almost one truck per minute, 24 hours per day.
The rock being moved will be Sydney Sandstone which can yield silica dust that has been linked to silicosis, a disease where fine particles of silica dust deposit on the lungs causing thickening and scarring of the lung tissue.
NorthConnex have said that management of spoil will be in line with NSW Environment Protection Authority (EPA) standards, limiting dust generation and transported loads would be covered.
Let’s hope so.
We could be in for a rough four years, but that is just my opinion…