The area is marked by the former open-pit mine (the site of the collapse) and vast piles of non-recoverable mining waste (tailings).  

The execution of this project was particularly complex due to the presence of asbestos-contaminated soils (tailings), posing a major material management challenge. Additionally, the route’s path through this former mining area involved significant variation in soil types. These challenges influenced every aspect of the project, from design to implementation. Professionals demonstrated great caution and creativity to develop custom solutions, prioritizing worker and local resident health and safety, as well as environmental protection.

To bypass the unstable collapse zone, the road alignment had to cross six tailings and run alongside a protected area including woodland and the Bécancour River. This required shaping the optimal path through the tailings and creating secure slopes, a colossal effort.

The Route 112 project faced major challenges, including the safe relocation of nearly 1,500,000 m³ of mining waste and the design of large slopes (100 m in length, 50 m in height) in a hilly landscape. Special measures were taken to ensure slope safety, including the construction of berms and benches to prevent rockfalls, as well as drainage channels adapted to the topography. An experimental method of slope revegetation was used, using sewage sludge to stimulate vegetation growth, prevent erosion and protect nearby watercourses.  

The roadway structure was custom-designed to fill voids in the soil, using crushed rock and geocomposites to ensure stability. Additionally, a new working method was developed in collaboration with CNESST (Quebec’s occupational health and safety commission) to ensure the safety of workers on-site in the presence of asbestos. Close air quality monitoring was implemented due to the presence of asbestos in the materials.  

The project also considered the need to maintain traffic in the urban area, relocate access to local industries, and connect the alignment to a safe section of the former road, providing access to local cottages.

The reconstruction of Route 112, described as essential to the local economy by the Minister responsible for the Chaudière-Appalaches region, was a resounding success in many respects. The specific constraints of this project were fully met, according to the client’s project manager (MTMD). The construction site successfully maintained urban traffic flow and minimized impact on local businesses through relocation studies.  

Moreover, in the absence of a designated occupational health and safety firm, the consortium temporarily took on this responsibility by implementing a framework program that contractors willingly followed, ensuring a safe working environment on-site.  

Finally, even though alignment adjustments were made during the project to enhance  safety and durability of the road, the project was completed with a $10 million cost savings to the original budget.  

Awarded at the Grands Prix du génie-conseil québécois, this project provides the region with a safer and more sustainable infrastructure.  

• New 10.3 km road  

• 56,231 tons of asphalt  

• 1,498,335 m3 of mining waste to be relocated, taken from six tailings

• Working method developed with the CNESST due to the presence of asbestos, including protective equipment, material humidification, air sampling during each shift and a designated route for transporting contaminated materials

• Recovery of fertilizing residual materials (sewage sludge) for revegetation of slopes

• Construction of structures, demolition of contaminated buildings, lighting, road marking and signage  

• Installation of culverts to ensure free passage for wildlife  

• Roads
• Environment
• Health and Safety