Domes for Sustainable Mining

Andalucía’s Twins When Minas de Aguas Tenidas, S.A. (MATSA), needed domes to cover their crushed ore stockpiles in Andalucía, Spain, they turned to Geometrica. Iberian Minerals Corp., a Canadian company with mining operations in Peru and Spain, owns the underground mine. When the time came to upgrade and revitalize, a new double circuit concentrator was designed to process 1.7 million tons per year of copper, zinc, and lead.

Domes for Sustainable Mining

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Geometrica proposed two domes for ore storage at 59m in diameter and 29m high with a surface area of 4,900 square meters and floor area of 2,700 square meters. Each dome had 14,400 tubes and 4,100 connectors and two openings, one for the feeding conveyor ingress and the other for dozers and other heavy machinery. The “twins” were designed to contain dust, protect the raw materials from the elements, and reflect the commitment of the Iberian Minerals Corp. as environmental leaders.

By Melanie Saxton

Perhaps you’ve heard the saying, “If it’s not created in a laboratory, then it’s very likely mined.” The world is built on the metals and raw materials extracted from the earth. The industry creates jobs, bolsters local economies, and encourages foreign investment. But mining has also taught an entire sector the meaning of the word “green” — a design factor in which Geometrica specializes.

No longer are mining bulk-material stockpiles left uncovered to contaminate soil, groundwater and air. Rather, eco-friendly Freedomes® are designed to address a host of environmental challenges. Geometrica designs long span domes and barrel vaults that prevent runoff, contain dust and spare landscapes. Vegetation, livestock and communities are protected against pollutants. Freedome technology keeps stockpiles under cover, including ores of copper, zinc, and precious metals, bauxite, potash, gravel, limestone, coal, clay and more.

San Cristobal: 140m Zinc Ore Stockpile in Bolivia Located in the Altiplano of the Andes Mountains, San Cristobal is the largest mine in Bolivia. The open-pit extraction of zinc, silver and lead ore requires the transportation of 150,000 tons of rock and the processing of 40,000 tons of mineral daily. And it needed a cover.

You would think terrain might be a problem when building a 140m long span dome, especially 4,000m above sea level. Not so with Geometrica’s Freedome system. Together Geometrica and Bolivian contractor Carlos Caballero SRL created a rugged solution high in the Bolivian plains.

Anchored by concrete foundation, the largest dome of its kind in South America was erected around a live stockpile in an irregular shape with no downtime. The dome is designed to withstand wind speeds of up to 150 kph and an ice load of 110 kg per square meter. It accommodates a 9m change in elevation over an astounding 140m, fitted to the terrain.

What Can Geometrica Do for You? The above examples prove that industry and nature can coexist on the largest scale imaginable. Regardless of geography or climate, Geometrica designs dual-duty domes that 1) protect stockpiles from the elements, 2) protect the environment from the stockpiles. Our mission is to provide solutions to industries around the world. The question is, “What can Geometrica do for you?” g eo metrica. com

To date, Geometrica has built such structures in 30 countries, helping the world’s industrial footprint tread more softly around Mother Nature. Below are examples of domes and barrel vaults that have changed the landscape of the world.

Durango Dome The Velardeña mine and its neighboring town in the Mexican state of Durango, share the same topography and environment. Industrias Peñoles oversees the mine and utilizes state-of-the-art technologies to safeguard air and water supplies. Geometrica designed a dome to enclose the mine’s stockpile. Two conveyors feed material into the dome spanning 64m in diameter and 31m in height.

Geometrica offers real solutions that: • Are built by local crews without special or heavy equipment.

• May be supported on slopes or irregular terrain.

• Allow the pile to remain in operation during construction.

• May be designed to resist high loads on the apex or encapsulate the discharge point.

• Reduce emissions, noise, dust and contaminants.

Caserones: A New Summit in the Andes Cresting 94m above its 4000m high surrounding terrain, the new Caserones dome could be confused with one of the peaks that rise around it. Also, at that altitude above sea level, the facilities are subject to snow loads that reach 800kg/m2 and wind gusts of 300kg/m2. The stockpile, one of the largest in the world, is set in a steep ravine and has an elevation change of 20m between its lowest and highest supports.

The challenge was to build a dome to span a whooping 145m span and be tall enough to shed the brutal snow accumulation in winter.

Geometrica’s extensive experience with long span “all-terrain” free-form structures made them the logical choice to design and construct the magnificent project. The dome is now the largest and tallest stockpile cover in South America. Geometrica also supplied a concentrate storage dome and connected barrel vault for environmental protection at this mine.

Dome Cover, Dust is Done At the entrance of the Cerrillos Canyon in northern Chile lies a copper ore processing facility. Located 30 km southeast of the city of Copiapó, this area is also an important wine region. The vineyards needed to be protected from fugitive dust from the crushing and handling operations. Foam sprays and fabric barriers were ineffective, and a Geometrica Freedome provided the perfect solution.

Geometrica overcame several design obstacles. For instance, equipment and conveyors were not laid out with an enclosure in mind. The main area encompassed more than 5000m2 in a shape that was irregular after several expansions. Existing equipment and buildings dictated the shape as crushers and sifter equipment had to be enclosed, while a hopper had to remain outside. The supporting structure had to bridge existing buildings. There was no way to fit a conventional circular dome on this site.

A Freedome, plus two smaller domes, was installed from the foundation by local labor, progressing toward the apex ring by ring. No scaffolding, welding, or operating downtime was required. Cladding consisted of rectangular corrugated metal sheets with a polyester finish. Now dust emissions are controlled from the plant’s material processing while the vineyards are protected.

High Capacity Tripper Storage: El Brocal El Brocal, Peru’s largest publicly traded precious metals mining company, is committed to environmental protection. This commitment extended to the architecture of its new storage building for copper ore in Cerro de Pasco, located in central-western Peru. At 4300m above sea level, Cerro de Pasco is one of the highest-altitude cities in the world. Here, Geometrica’s structural beauty blends with the environment. Equally important, the enclosed barrel vault protects the environment from the dust generated when the copper ore is moved to and from storage.

The new storage structure presented challenges. It had to be built within the limits of the finished building, and copper ore would have to 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 material loads efficiently. It also needed a structure strong enough to support the weight of the conveyor equipment, as well as vibrations and impacts created by the moving copper ore. Furthermore, even in the constrained space, El Brocal management mandated that construction take place with minimal interruption to its operations.

To build the structure, half arches were assembled on the ground, then lifted with cranes and joined at the apex with Z purlins and bracings. The end wall was built 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. Installation met the severe site constraints, and the finished structure is light, beautiful, and designed to resist the loads from the tripper and the high-altitude environmental conditions.

7th Wonder of the Mining World With ongoing strong copper prices, construction activities in Northern Chile continue. Within this large copper producing region is the open pit copper mine Sierra Gorda, thought to be a “seventh wonder of the mining world.”

More precisely, this breathtaking enterprise is the seventh largest copper development on planet earth.

Located at the doorstep of the Chilean commune in Antofagasta Province, the environment is a priority. Geometrica designed two circular domes to protect the surrounding locale from air, particulate and water pollution. One application spans a remarkable 122m over copper ore, and the other spans 62m over concentrate. The concentrate dome features internal cladding. This type of cladding protects the galvanized steel structure from any possible corrosive attack by the copper concentrate in the building.