Belzona has used its own concrete repair and rebuild composite to keep a primary crusher operational at a copper mine in Brazil.
A common cause of wear in the mining industry can be vibration. This can cause eventual fatigue, resulting in cracks and a loss of material in operational equipment. It can also lead to premature failures in areas such as concrete foundations and their anchoring systems.
“Generally speaking, concrete can be considered too brittle and weak to absorb such constant impact and vibration transferred from the equipment,” Belzona said. “Once the concrete has failed, anchor bolts in the foundations can loosen, further aggravating the effects of the vibration on the foundation.”
A copper mine in Marabá, Brazil, found this to be the case with its primary crusher, according to the company, with the base of the primary crusher needing to be rebuilt due to weakening caused by vibration. The 3,000 t/h primary crusher weighs 336 t, is 9.5 m high and 5.6 m wide, contributing further to the amount of stress being put on the foundations, Belzona said.
“Being one of the biggest copper crushers in South America, and with copper being traded at around $6,000/t, every hour of shutdown can result in a loss of almost $20 million,” the company said.
A solution was required that could rebuild the foundation and bases of the primary crusher, while being able to withstand high dynamic and impact loads without shattering and breaking, according to Belzona. “Excellent mechanical properties and a fast curing time were also critical in ensuring the primary crusher would return back to service in as little time as possible.”
The solution used was Belzona 4111 (Magma Quartz), a high-performance concrete repair and rebuild composite.
Using an impact hammer drill, the first two layers of concrete were removed to reach the steel reinforcement structure.
“Particularly with concrete repairs, surface preparation is critical in its success,” Belzona said. ”The substrate needs to be free from contamination, free from excess moisture and any loose material needs to be removed.”
The area was cleaned and degreased with solvent and compressed air was used to remove the entire repair area of loose debris and dust. A conditioner was then applied to ensure an optimum bond between the substrate and repair materials.
The perimeter of the repair area was initially built up, later acting as a mould for a slurry mix of Belzona 4111. The material was able to level evenly to recreate a foundation at the base of the primary crusher, according to Belzona.
“The implemented solution offered resistance to high vibrations and dynamic loads due to its high mechanical strength. The system adhered to both metal and old concrete allowing for a homogeneous load distribution, without weak spots during the anchoring/grouting procedure and service,” the company said.
The assembly of the machine to the structure commenced in as little as four to six hours after application, according to Belzona, with a full return to service possible in some 16 hours.
“The fast turnaround time allowed the copper mine to continue its processes without a majorly disruptive or costly downtime,” the company concluded.
Specialising in erosion, corrosion and chemical protection, Belzona calls itself a world leader in the design and manufacture of repair composite materials and protective coatings for machinery, equipment, buildings and structures.