El Brocal: Strength and beauty high in the Andes
In Peru and elsewhere, mining is often controversial. But El Brocal, Peru's largest publicly traded precious metals mining company, is committed to preserving the environment wherever it operates. This commitment extended to the architecture of its new storage building for copper ore in Cerro de Pasco in central-western Peru.
Cerro de Pasco, high in the Andes, is 14,200 feet above sea level--one of the highest-altitude cities in the world. The landscape is stark, and beauty is found in simplicity. Here, Geometrica's structural beauty blends with the environment. Equally important, the enclosed structure protects the environment from the dust generated when the copper ore is moved to and from storage.
Geometrica's structural system attracted the attention of the director of PHB Weserhütte, S.A.'s technical department, José Ramón Prado, who saw Geometrica's Aguas Teñidas domes at a copper, zinc and lead mine in Andalucia, Spain. The combination of strength, beauty and flexible construction appealed to Prado, and he was further impressed with the economy of the Geometrica system. "We are very satisfied with the building," said Javier Vizcarra, El Brocal projects and construction management assistant.
A hybrid structure
The new storage structure was to be built within a constrained space, which meant that copper ore must be delivered via a tripper conveyor suspended along the length of the building's apex. Therefore, the building's shape had to support both wind and live loads efficiently. It also needed a structure strong enough to support the weight of the conveyor equipment, as well as the loads, vibrations and impacts created by the conveyed copper ore. Furthermore, even in the constrained space, El Brocal management mandated that construction take place with minimal interruption to its nearby mining facilities.
"We decided on a hybrid structure that combines Geometrica's hub-and-spoke system with welded components," said Priscilla Tamez, Geometrica's project manager for the building. “We designed the structure, a longitudinal arch, to optimize space and structural requirements. We shaped the structure with sufficient width to clear the ore stockpile--and sufficient height to suspend the stacking equipment. An opening at the end of the building allows for the passage of the conveyor."
The structure was remarkable in two ways: Geometrica combined its mechanical joint system with high-strength welded steel. Second, the tripper support was a completely separate framework that was assembled and joined after the longitudinal structure was complete. "The finished structure is light and beautiful, yet strong enough to resist the tripper loads," said Tamez.
A 10-month process
Once the structure was designed, Geometrica set about assembling the components in its Monterrey, Mexico, fabrication facility. Four months later, the components were shipped in containers to the construction site--bar-coded, labeled and packaged in the correct order for easy, flawless and fast assembly by local laborers.
To build the structure, the contractor assembled half arches on the ground, then lifted them with cranes and joined them at the apex of the structure. The arches were joined with Z purlins and bracings. The end wall was assembled in traditional Geometrica fashion, by assembling "spiders" on the ground, then lifting them into position. The tripper likewise was assembled in sections on the ground, then lifted to its position and joined after the longitudinal structure was complete. The assembly took about six months.
El Brocal's Vizcarra said, "Geometrica’s technician, Eduardo Medellín, was extremely helpful, explaining what to do and what not to do—and overseeing all the details necessary to assemble the structure. We look forward to working with Geometrica again.
In fact, Geometrica is currently manufacturing over half a kilometer of longitudinal structures that are similar in design to El Brocal’s. They will be installed in various countries around the world.
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