Tarkwa Gold Mine Geotechnical Boreholes and Hydrogeological Site Investigation


Gold Fields Ghana


July 2013


Tarkwa, Western Region, Ghana

Tarka Gold Mine Geotechnical Boreholes and Water Wells
Knight Piésold Consulting Engineers were appointed by Gold Fields Ghana to prepared detailed designs for the construction of Tailings Storage Facility 5 at Tarkwa Mine. To obtain information for these designs, hydrogeological and geotechnical site investigations were required. PMI were appointed in June 2013 by the Client to provide these services.

Site Investigations Scope

  • 5no. Geotechnical Boreholes to 21m depth including SPT testing, Disturbed Continuous Window sampling, Undisturbed Shelby Tube Sampling;
  • 5no. 200mm diameter, 50m deep water wells inclusive of pump testing, steel casing, PVC filter screens, lockable steel stand pipe, and hole finishing;


  • Work was supervised by PMI’s qualified Civil Engineer;
  • A PMI Fraste ML hydraulic rig and specialist crew undertook the geotechnical boreholes. The general ground formation consisted of 2-3m of silty clays and then weathered mudstones or sandstones;
  • Robit ‘Down Hole Hammer’ drilling equipment was used on formations made up of broken rock and boulder matrices;
  • Water wells were drilled using a high-powered DTH drilling rig using 250mm equipment;
  • A 55 litre/min submersible pump and accessories was used for pump testing of the wells.

Project Outcome

  • The project was executed successfully in July 2013;
  • The Client was satisfied with the geotechnical and hydrogeological work.