This expansion and upgrade of the Spence mine in Antofagasta, Chile was completed in July 2021. BHP, the mine owner, can now begin extraction of copper before the end of the year. PENETRON ADMIX was specified for the key concentrator tank to ensure a durable, long-lasting concrete structure, even under the aggressive conditions of copper ore processing.
Broken Hill Proprietary (BHP), formerly known as BHP Billiton, is an Anglo-Australian multinational mining, metals and petroleum company headquartered in Melbourne, Australia. Incorporated in 1885, BHP engaged in the mining and marketing of iron ore, copper, oil and gas, diamonds, silver, lead, zinc and a range of other products such as flat steel. As the owner of Escondida, the world's biggest copper mine, the company is one of the largest copper producing companies in the world.
BHP’s $52 million infrastructure project to expand the Spence open-cut copper mine in northern Chile, also known as the Spence Growth Option (SGO), will extend the service life of the mine by approximately 50 years. The SGO project upgraded the mine pit, the mine’s waste dump, the concentrator plant and the powder magazine. In particular, the project included the design, engineering, and construction of a conventional, large-scale sulfide concentrator for both copper and molybdenum ore. The concentrator’s concrete tank is exposed to a variety of chemicals, including but not limited to copper sulfide, iron, and a series of salts of other metals.
Challenging Copper Extraction Processes
Because of the aggressive physical and electro-chemical processes used to extract copper from its ores, the technical specifications for permeability of the concentrator’s concrete tank were rigorous,” explains Domingo Lema, Managing Director of Penetron Chile. “The originally specified waterproofing solution, a pore sealer product, did not meet the project’s required permeability standards, which led to a search for a more robust alternative.”
The ready-mix supplier, Petreos Society, recommended PENETRON ADMIX-treated concrete as the only waterproofing solution capable of meeting the project’s permeability specifications. Salfa Corporation, the project’s general contractor, specified PENETRON ADMIX to treat 13,000 m3 of concrete for the concentrator tank.
Once added to the concrete mix, the active ingredients in PENETRON ADMIX react to moisture to generate a non-soluble crystalline formation throughout the concrete matrix. This crystalline network permanently seals microcracks, pores and capillaries against the penetration of water- or water-soluble corrosive chemicals from any direction, protecting the concrete and embedded reinforcing steel from deterioration, even under the harsh processing conditions of the Spence copper mine.
Providing a Comprehensive Guarantee of Impermeability
“Penetron got the job thanks to favorable costs and a more comprehensive guarantee of permeability reduction and self-healing of cracks throughout the service life of the concrete of the concentrator tank at the Spence mine,” says Domingo Lema.
Finally, thanks to the excellent performance of the PENETRON ADMIX-treated concrete, the general contractor has decided to expand the use of PENETRON ADMIX to other structures planned for the SGO upgrade project.