Sustainable gypsum mine closure and reclamation planning

For nearly a century, gypsum mining has shaped the landscape near Windsor, Nova Scotia. Canadian Gypsum Corporation (CGC Inc.), continues this legacy, operating several quarries that supply gypsum and anhydrite for use in cement, wallboard, plaster, and agricultural products. However, as operations came to an end for the Windsor site, the regulations required progressive reclamation of the private mine lands. In addition, the site needed a plan for decommissioning and demolition of the site’s gypsum mine and marine load-out facility. 

We supported CGC across three gypsum operations in the Windsor, Nova Scotia region, providing a broad range of environmental and engineering services over several years. Our involvement began with environmental assessments and baseline studies, followed by public and First Nations consultation and the development of reclamation strategies for both mining and marine load-out facilities. These early efforts laid the foundation for a long-term partnership focused on sustainable closure and future land use planning. 

As part of an Environmental Assessment extension for the site, GHD developed conceptual reclamation plans that reflected local legislation, community and regulator feedback and CGC’s vision for the final landscape. The plans were designed to mirror the natural features of the Avon Peninsula, an area defined by tidal rivers, karst terrain, agricultural activity and a northern climate. Plans for reclamation were made across more than 1,000 acres, encompassing overburden piles, wetlands, mined areas, quarry ponds and previously reclaimed lands. 

To support this, we conducted a comprehensive site evaluation to inform a reclamation plan submitted to the Province. This included predictive modeling of ground and surface water levels post-flooding, geotechnical assessments for slope stability, vegetation surveys to identify beneficial species and advanced mapping through LIDAR and bathymetric surveys. We also completed asset inventories, phased site assessments and hazardous materials surveys.  

In parallel, we were retained to lead decommissioning and demolition planning for the gypsum mine and marine load-out facility. This work formed part of CGC’s broader care and maintenance strategy. The site included 60 buildings ranging from small storage sheds to a 150,000 ft² production facility and a large marine dock structure capable of loading 12,000 tonnes of gypsum rock per hour. Structures dated from the 1950s to the 1990s and included steel piles, concrete walkways and mooring dolphins weighing up to 200 tonnes. 

Our scope included detailed inspections of buildings and dock infrastructure, a full HAZMAT survey to identify designated substances (including asbestos, lead, PCBs, and ODSs), and recommendations for safe abatement and disposal. We coordinated all regulatory meetings and filings, and developed cost forecasts for decommissioning, closure and salvage value recovery of production equipment and recyclable materials such as structural steel and copper.

The comprehensive site reclamation plan helped meet the diverse needs of CGC and its stakeholders, including regulators, local communities and future operational interests. The plan outlined areas to remain as mine reserves, zones suitable for early reclamation, and sections of the pits to be flooded and transformed into lakes. It also included detailed costing for reshaping, revegetation and long-term monitoring, providing CGC with a clear and actionable roadmap for closure. 

For the local community, the project delivered environmental and safety improvements, enhanced transparency through public engagement and laid the groundwork for future land uses that reflect the region’s natural character. The reclamation strategy also supports long-term ecological resilience in an area defined by sensitive tidal ecosystems and agricultural activity.