Located in northern Goiás State, Chapada is situated approximately 320 km north of the state capital of Goiania and 270 km northwest of the national capital of Brasilia, at low elevation of approximately 340 to 400 m above sea level. The town of Alto Horizonte, with a population of approximately 5,800 people, lies 4 km northeast of the mine. The operation is supported by road access and has good connections to the local and national road network. Electricity is provided by the national grid via a private 85 km 230 kV line.
Chapada is a conventional open pit truck and shovel operation which benefits from a low strip ratio and an in-pit crusher. The operation has been in continuous production since commissioning in 2007. Mine production is currently from three open pits in close proximity, planned to eventually join into a single pit, collectively referred to as the Chapada open pit mine.
The processing facility at Chapada comprises a single-line plant designed to treat sulphide ores at a current capacity of approximately 65,000 tonnes per day or 24 million tonnes per year. The conventional crush, grind and flotation processing produces a high-quality gold-rich copper concentrate.
Plant expansion opportunities to increase the processing rate to a range from 28 to 32 million tonnes per year and the relocation of some plant infrastructure to allow the push-back of the pit wall for the development of the Sucupira orebody were being studied by Yamana Gold. Lundin Mining is further evaluating these and other value creating scenarios for expansion by leveraging our technical expertise, financial strength and the copper-focused exploration potential of the mineral property.
The gold-rich copper concentrates are transported by truck to the port of Vitória where they are shipped to a variety of overseas smelter customers.
Geologic and Exploration Overview
The copper-gold sulphide mineralization found at Chapada is hosted in a well deformed and metamorphosed, structurally hosted, system with comparable grades and ore mineralogy to porphyry/skarn copper-gold deposits of island arc settings. The copper mineralization of the Chapada and Sucupira deposits is principally chalcopyrite with minor amounts of bornite. Fine grained gold is closely associated with the sulphide mineralization. The copper mineralization and grade are highest in the central zone of the Chapada deposit along the anticline axis, though copper mineralization is pervasive over a broad area. Gold mineralization is spatially uneven and is believed to have been remobilized by low temperature alteration events.
Lundin Mining believes that copper exploration potential exists on the mineral package. Recent exploration surrounding the mine undertaken by the previous owner had focused on the search for additional blind gold-rich deposits. There are few outcrops in the mine area due to an approximately 30-metre-thick laterite-saprolite cover. Exploration techniques have historically included primarily soil geochemistry, geological mapping, and exploration drilling. Generative exploration activities were restarted in 2014 working with the deformed/metamorphosed copper-gold porphyry/skarn model for the region. As a result, the Sucupira deposit was discovered close to the main Chapada orebody and several other targets have been identified for further exploration.