The formerly producing Punitaqui copper mine in the Coquimbo region of Chile is planned to be restarted by Battery Mineral Resources (BMR), a multi-commodity resource company based in Canada.
The mine was last operated by Glencore from 2010 to 2018, followed by Xiana Mining until April 2020. BMR acquired the property from Xiana Mining in July 2021 and has since then been aggressively engaged in exploration and infill drilling to increase resources and define a mine plan to restart copper production at Punitaqui by the end of 2022.
Punitaqui mining complex comprises a centralised process plant and four satellite copper deposits namely Cinabrio, Cinabrio Norte, San Andres and Dalmacia, all of which have established underground access and drill-ready resource targets.
BMR’s drilling campaign at Punitaqui has been focused on the San Andres and Dalmacia deposits. The company plans to update the resource estimate and carry out underground development to restart production from Cinabrio and San Andres in the first half of 2022.
The Punitaqui copper mine is expected to produce up to 25 million pounds (Mlbs) of copper a year, upon restart.
Punitaqui copper mine history
Discovered in 1780, the Punitaqui copper-gold deposit was initially exploited by the Spanish government. The Los Mantos deposit within the Punitaqui mining district remained the biggest source of gold and mercury in Chile until 1981.
Tamaya Resources, a company based in Australia, completed exploration and feasibility studies to exploit oxide copper resources at Punitaqui between 2007 and 2010. It had also constructed a processing plant and commenced mining during that period.
Glencore acquired the brownfield project, upgraded the plant and restarted mining at Cinabrio through its wholly-owned subsidiary Minera Altos de Punitaqui (MAP) in 2010.
Xiana Mining, a Canadian mineral resource company, acquired MAP from Glencore in May 2018 and continued operation until it placed the mine on care and maintenance in April 2020 due to the fall in copper prices because of Covid-19.
Location, geology, and mineralisation
Located 35km south of Ovalle in the Coquimbo region of Chile, the Punitaqui mining district spans 25km within a classic iron oxide copper-gold (IOCG) manto-type copper belt hosted within the volcano-sedimentary Agua Salada Complex of Jurassic to lower Cretaceous age.
The Punitaqui project area comprises four mining leases and 11,838ha of concessions, including 6,900ha of exploration and 4,938ha of exploitation concessions.
The San Andres copper deposit is located 500m south-west of the high-grade Cinabrio deposit, which was mined by Glencore and Xiana Mining, whereas the Dalmacia target lies 20km south of the Cinabrio ore body and 6km south of the Punitaqui processing plant.
Mineralisation at Cinabrio, San Andres and Dalmacia mainly comprises chalcopyrite, bornite, pyrite and chalcocite.
Exploration drilling at Punitaqui
BMR started phase one exploration and in-fill drill programme at Punitaqui in July 2021 and completed 8,156m of drilling in 38 holes at San Andres and 6,504m of drilling in 33 holes at Dalmacia as of January 2022.
It has found significant copper intercepts at both the deposits and is currently developing the 3D geological model with a target to provide updated resource estimates in the first half of 2022.
Mining and ore processing
Punitaqui will be an underground mining operation feeding the extracted ore to the existing 3,600 tonnes a day (tpd) process plant that houses a conventional copper sulphide crush-grind-flotation circuit to produce copper-gold concentrate.
The process flow comprises three-stage crushing and single-stage ball milling, followed by rougher-scavenger flotation, and three-stage cleaning, thickening and dewatering to produce the final concentrate.
The Punitaqui processing plant is equipped with a 255t/h primary jaw crusher, a 415t/h secondary cone crusher, three TC51 tertiary cone crushers, and two single-stage ball mills equipped with a 1,650kW drive and measuring 20ft long and 14ft in diameter each.
The mine complex is accessed by paved roads connecting Punitaqui, Ovalle, and the Port of Coquimbo, which is located 120km north of the project site.
A network of four existing wells at the site will be used to supply water for the copper mine operation, with electricity to be provided by a local supplier through the existing transmission infrastructure.
The project site also features a series of tailing storage dams to dispose of tailings from the process plant.
JDS Energy and Mining has been engaged to provide the updated resource estimate of the project. It also prepared a technical report for the project for Xiana Mining in 2018 with assistance from GeoWiZ and Holland & Holland Consultants.