Project Spotlight – Salares Norte Gold Project

Gold Fields announced in January 2021 that it had formally began construction of the mining infrastructure at the $860m Salares Norte project in the Atacama Region in northern Chile. At the time, the company stated that construction had already advanced 15% with the building of the mining camp which accommodates 1,800 people, associated infrastructure, and access roads.

Salares Norte is a gold and silver deposit. The project is planned to produce an average of 355,000oz/y gold-equivalent over its first 10 years, at an estimated all-in sustaining cost of $552/oz, with an 11.5-year mine life. Salares Norte will be GoldFields’ second mine in Latin America, joining Cerro Corona in Peru which produces about 291,000oz/y gold-equivalent.

The company started pre-stripping of the gold-silver project and construction of the process plant in January. Construction will involve nearly 2,700 people during its peak, and  Gold Fields expects to employ around 900 employees and contractors once it is operational.

The Salares Norte project has been 20 years in the making when the deposit was first discovered. The location creates some unique challenges for the design of the mine due to the height and geographical environment. It is located between 3,900 and 4,700 m above sea level, in the middle of the highest peaks of the Andes mountain range and the driest desert in the world.  This has forced the Goldfields to employ sustainable technologies that reduce its environmental footprint. These include solar PV power and filtered tailings to optimise water use.

Mine Design

• Salares Norte will be an open pit with conventional equipment.
• Operations will consist of mining and blasting services performed by contractors.
• Mine planning is based on open pit mining to exploit the Brecha Principal and Agua Amarga deposits.
• The two pits are located approx. 500m apart, eventually the two pits will merge into a single put due to the backslope. Waste will be placed either the south or north WSF. Ore will be hauled to either the RoM pad or one of the grade-bin stockpiles, south of the pits.
• Production is based on a constant plant throughout rate of 2 Mt/y and peak total material movement of 44 Mt/y. During the life of the mine, 331 Mt will be mined, consisting of 22.2 Mt of ore to the plant and 308.8 Mt of waste, resulting in a strip ratio of 13.9:1. Prestripping will be some 50.6 Mt. The gold grade averages 4.96 g/t and silver 55.6 g/t.
• To improve the project economics, the mine plan is based on an accelerated mining strategy, thus all ore must be stockpiled and re-handled to feed the crusher. This strategy will provide flexibility to manage gold and silver grades for improved gold recoveries, especially during the first years of operations. With this strategy, the mine and plant are decoupled.

Mine Operations and Technology

• The main haulage fleet is composed of 18 Caterpillar 191 t class 789D trucks supplied by Finning. Nine of them will be onsite at the mine in March 2021 while the rest will begin to arrive in 2022. 
• The fleet will be operated by mining contractor Ingeniería Civil Vicente (ICV) with the trucks loaded using large hydraulic shovels.
• Wenco International Mining Systems will provide their signature fleet management system and BenchManager high-precision machine guidance systems to manage the site’s excavators, drills, and dozers. The site has also ordered high-precision systems for use on its fleet of trucks.
• Nokia has partnered with Claro Chile to install a private LTE/4.9G network making it one of most digitalized mines in Latin America
• The network will be used by the operator to support automation of  72 connected vehicles and machines including remote-controlled trucks, excavators, and drills, with drones also to be deployed in future. 
• The network will use 150 sensors for operational processes, monitoring and accident prevention.
• ABB working with Claro and Nokia has already tested telematics using satellite connectivity between the project located near Copiapo at 4,700m above sea level and Chilean capital Santiago, some 1,200 km away.

Pro

Processing Infrastructure

• The processing plant designed to process 2 Mtpa will be located in the Southeast of the main pit area at an altitude of 4,500m.
• Ore will be crushed, milled, and thickened, with thickener underflow pumped to cyandide leaching.
• Mineral processing orders for the project were announced in 2020. FLSmidth sold three system packages for Salares Norte – a Merrill Crowe plant, an AARL (Anglo American Research Laboratories) elution circuit and a refinery.
• To minimise the use of water and improve the physical and chemical stability of our tailings, the project will use filtered tailings. Salares Norte will be a benchmark plant for dry tailings processing.
• Metso Outotec is delivering three of its Vertical Plate Pressure Filters with all the ancillary equipment for dry tailings processing as well as one 4 MW SAG mill and one 4 MW ball mill, five thickeners and one clarifier.
• Due to the height of the project, there are some unique challenges, design and transportation of the equipment as well as commissioning will need to be done with special care. To save manpower at such a high altitude, Metso will semi-assemble the filters in its Service Centers and deliver them in six specially designed easy-to-assemble modules to the site

Energy for the Mine

• Goldfields is developing a 26MW hybrid solar and thermal power solution for the Salares Norte project. The aim to have this functional once the operation starts production in early 2023. Diesel generators will provide 16MW and the solar unit 10MW of power, which is set to save the mine over US$7m in energy costs over the first 10 years, as well as US$1m in carbon tax offsets.
• Aggreko signed a ten-year contract in January 2021 to provide a 25.9 MW hybrid solar and thermal power solution for the project.
• The hybrid system will comprise both tailor-made high-altitude performance diesel gensets and Aggreko solar power units, optimised for off-grid applications and geared for the extreme wind conditions the units will experience.
• The solar farm will be split into three smaller farms due to the higher altitude of the Andes making it complex to find a single space for the required size farm.
• The solar farm will provide 100% of the power during high penetration hours, while the diesel can provide 100% of the power the rest of the time, and during the night.

Ax Legal is a legal and business advisory firm that works with foreign companies in Latin America. Our team of legal and commercial advisors have a distinguished track record of helping foreign technology and services companies to grow and operate in Latin America. Over the years, we have worked with starts up, mid-size businesses, and publicly listed companies. The one common factor that connects are clients is that they are leaders in their field, providing innovative technologies and services to the industrial sectors.

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