Wassa Gold Mine

Project Overview

The Wassa Gold Mine is located near the village of Akyempim, Wassa District in the Western Region of Ghana, some 260 km from Accra. The former heap leach pad, now known as tailings storage facility 1 (TSF 1) extension, is bounded to the south, east and north by natural hills and to the west by a coffer dam, separating TSF 1 from TSF 1 extension.

The TSF 1 extension basin floors and walls were lined entirely with HDPE geomembrane to reduce the likelihood of contaminants seeping into the environment. A comprehensive drainage and water management system was constructed, including:

• Groundwater drainage systems
• Tailings underdrainage systems
• Groundwater and underdrainage collection sumps with riser pipes and pumps to reclaim water to the existing TSF 1 decant pond that was already operational

Project Role

Knight Piésold conducted detailed design incorporating the former heap leach pad area into TSF 1 extension and provided a resident civil construction engineer to carry out the field engineering and supervise the earthworks soils laboratory, field testing, and the HDPE geomembrane liner installation. Other services included:

• Providing technical advice to construction activities, HDPE deployment, and installations
• Supervising earthworks and subgrade preparations to receive HDPE geomembrane installations
• Carrying out quality assurance and quality control for groundwater and underdrainage construction within the basin floor
• Carrying out on-site field engineering and material selection required to optimize the designs, daily inspection of all construction activities, and soils quality assurance
• Managing the soils laboratory for construction quality control of the earthworks