They have $3m US just for a starter dam?? $4m. Where did that come from? The real Dam is going to be built from overburden.
"Detailed engineering design for the Tailings Dam has been completed by local group ALB and GeoHydroTech Engenharia who are highly experienced in the design and construction of tailings impoundments in Brazil. The cost of the starter dam facility is estimated at ~US$3m."