b'PROJECT PROFILEPHOTOS COURTESY OF METROLINX PREPARATION FOR TUNNELLING EXTRACTION SHAFTThe Scarborough Subway Extension willBut by that time, crews had alreadyHowever, the proposed extraction-shaft be the first subway project in Torontobegun to prepare for the work ahead.location adjoins the Scarborough Health to operate in both directions within aIn early May they started to identifyNetworks General Hospital. While the single tunnel with a 10.7-metre internaland remove any hazardous materialsoccupants of the healthcare facility are diameter, says Mark Ciavarro, vice- from buildings on the site. Utilitiesno doubt looking forward to the subway president of the Scarborough Subwaywere disconnected and buildings werestation that is also coming to the site, Extension. The launch shaft for thedemolished, then the site was gradedplanners were concerned about the tunnel boring machine will be about 28potential disruption that could be caused metres wide, 80 metres long and 30and partly paved. by the additional excavation ofmetres deep. To give a sense of how biga 40-metre shaft to accommodatethat is, the hole will be about as deep asThe initial concept for tunnelling wouldthe two TBMs.a 10-storey building is tall. To preparehave involved two TBMs that would have the launch shaft site, about 300 secantbeen deployed from launch shafts at theThey were also eager to minimize piles will be drilled at the tunnel intersections of Sheppard/McCowan andthe impact of the work to be done at launch site. Midland/Eglinton. The plan called forMidland/Eglinton, since businesses the two machines to move towards oneand residents there have been affected TUNNELLINGby another nearby project with the CONSIDERATIONS another until they would meet and thenconstruction of the new Kennedy Station Metrolinx officially broke ground on thebe removed at an extraction shaft thaton the Crosstown Line. Consequently, the Scarborough Subway Extension on Junewould have been located at Lawrenceinitial plan was modified to allow for just 23, with a goal of service by 2029-2030.East/McCowan. one TBM, which will start work via the BUILDERSDIGEST Quarter 3 202123'