Hydrogeologic Investigation of the Gold Reserve Incorporated Brisas del Cuyuni Concession in Southeast Venezuela

The following paper discusses the hydrogeologic investigation, groundwater modeling effort, and design of an optimized pit dewatering system for the proposed Gold Reserve Incorporated Brisas del Cuyuni Concession gold and copper mine in southeast Venezuela. This dewatering design presented some unique challenges due to the size of the pit and the climate of the region. The objective of this evaluation was to design a dewatering system for a 2.2 square kilometer pit, with special consideration for dewatering unstable clay-rich saprolite pit slopes, in an area that receives over three meters of rain a year. Using a MODFLOW-SURFACT groundwater model, an optimized dewatering system was designed that uses a combination of permanent dewatering wells, in-pit temporary wells, and in-pit sumps. The result is a dewatering system which not only dewaters a final pit influx of 350 liters/second of groundwater, but also has the required flexibility over the life of the mine to conform to a dynamic mine plan and challenging hydrogeologic conditions. In addition, on-going work utilizes the groundwater model to predict pit lake filling times and the steady-state interaction between the pit lake and the regional system