Chapada is an open pit copper-gold mine located 270 km northwest of Brasília in Goiás state, Brazil. The mine reached commercial production in 2007 and is an open pit truck/shovel operation, with ore being treated through a flotation plant with capacity of 22 Mt per annum. The Chapada mine plan includes three open pit mining areas including the Corpo principal open pit, which is currently being mined, and two other open pit mining areas to be developed called the Corpo Sul and Suruca deposits. The operations are expected to have a mine life of more than 20 years based on the 2016 Proven and Probable Reserve estimate of 559.5 Mt at a grade of 0.23% containing 3.2 billion pounds of copper (0.2 – 0.3 g/t Au cut-off).
The Chapada mine processing plant is designed to treat sulphide ore at a nominal rate of 60,000 tpd. The processing plant incorporates a conventional flotation process including primary crushing, semiautogenous grinding, secondary grinding, flotation, thickening, filtration and tailings disposal. Chapada produced approximately 50.4 million pounds of copper as well as 44,493 ounces of gold and 112,948 ounces of silver during the first half of 2017. Recoveries averaged 79% for copper and 55% for gold.
Sandstorm has a stream agreement to purchase an amount of copper from Chapada, equal to:
- 4.2% of the copper produced, up to a maximum of 3.9 million pounds of copper annually, until Yamana has delivered to Sandstorm 39 million pounds of copper; then
- 3.0% of the copper produced until, on a cumulative basis, Yamana has delivered 50 million pounds of copper to Sandstorm; then
- 1.5% of the copper produced thereafter for the life of the mine.
Sandstorm will make ongoing payments for each pound of copper equal to 30% of the spot price per pound of copper. Sandstorm made an upfront payment of US$70 million to acquire the stream in October 2015.