Case story

Ventilating a gold mine in Brazil. VACON® AC drives at Mineração Fazenda Brasileiro – a Yamana Gold* gold mine

- FRIDAY, 12 OCTOBER 2012 BY DANFOSS DRIVES

Located in Bahia, a state in north-eastern Brazil, Fazenda Brasileiro is an underground gold mine that has a carbon-in-pulp plant with a 3,500 tonne daily capacity. The mine has been in operation for over 20 years and has consistently replaced its mineral reserves as they have been mined. Gold mineral reserves increased by 104% in 2011 and an extension of the mine’s lifespan is currently being evaluated with a view to future operations.

Yamana Gold’s strategy is to use their existing mining properties to aid growth and expansion and to target more gold mining-related opportunities throughout the Americas. The company has invested in a major retrofitting project at the Fazenda Brasileiro mine to improve processes and provide the possibility for an increase in production, which would be brought about by decreasing the number of breaks in production.

To facilitate this retrofitting project, Vacon Latin America has delivered 18 VACON® X-series AC drives to control ventilation and pumping systems underground. Most of the drives each have a power capacity of 100 HP (75 kW) and are used in fan applications, powering the ventilation system used in the mine. Underground mining would not be possible without a ventilation and pumping system to provide sufficient oxygen underground. VACON AC drives bring energy savings by making it possible to adjust ventilation levels according to demand.

The pumping system plays a vital role in supplying water to the mine. It also helps in clearing excess water that appears as the result of excavation, and rain water during the rainy season, which could otherwise cause flooding.

VACON AC drives bring all kinds of other benefits as well. At the Fazenda Brasileiro mine, VACON drives improve the operation of the ventilation and pumping systems and their processes, at the same time making them more reliable. During retrofitting, AC drives that were difficult to access could be relocated in more reachable positions.

Environmental factors in underground mines, such as dust, moisture and temperature, can easily damage electronic components. IP66/Type 4X enclosures provide protection against these elements while simplifying the process of replacing drives in mines. And that’s not all! The IP66/Type 4X enclosures also improve drive reliability and extend the range of places where drives can be used.

VACON AC drives bring significant energy savings to many application processes, and the Fazenda Brasileiro mine is no exception. The drives can cut energy consumption by around 30% in comparison with the system previously in use, which was the direct online (DOL) system, a widely-used method for starting electric motors that applies full line voltage to the motor terminals. In addition, the drives provide speed control, which greatly reduces the pressure placed on the motor during starting and stopping.

The drives can be installed directly on the wall in the underground mines without the need for costly cabinets, which gives further savings.

Yamana Gold has experience of working with several AC drives manufacturers and has been very pleased with their latest choice of drives supplier. “Vacon has provided the solution to the drives problems that were affecting our processes,” says José Adeílson, Electrical Maintenance Supervisor, Underground Mine, Yamana Gold.

For Yamana Gold, the decisive factors in choosing the drives supplier included Vacon’s proactive approach in the pre-sales phase, the local availability of spare parts and after-sales services, and a good purchase-level based on project budgeting.

Vacon has been active in Brazil through a partnership cooperation since 1998. Vacon started Latin American business operations of its own in 2009 when it established a subsidiary in Barueri, São Paulo. Vacon Latin America has another sales office in Lauro de Freitas, Bahia. In addition to a large customer base, Vacon Latin America has several partners and distributors in Latin America.

In less than a decade, Yamana Gold has become a strong gold mining company with seven low-cost mines in production and three more to come. A pipeline of projects, an aggressive exploration program focused on organic growth, and an enviable financial foundation mean growth is set to continue. Yamana Gold’s seven mines in the Americas produced 1.1 million gold equivalent ounces in 2011. By 2014, annual production from ten mines is expected to reach 1.75 million ounces. Yamana Gold considers itself to be one of the most significant growth companies in the gold mining industry.

Yamana Gold’s Fazenda Brasileiro mine, located in Bahia State in northeast Brazil, produced 55,163 ounces of gold in 2011. It has an estimated production capacity of 50-60,000 gold (oz.) for 2012. The retrofitting project at Fazenda Brasileiro will be completed during 2012.

CLX2 and Lagoa do Gato, the two new mineralization zones at the Fazenda Brasileiro gold mine discovered in 2009, have been identified as having significant potential for high-grade sources of ore for the mill. Both infill and extension drilling confirm the continuity of mineralization in both areas. The VACON AC drives have been in operation at the Fazenda Brasileiro gold mine since 2010. Most of the VACON AC drives have IP66/Type 4X enclosures, which provide good protection against dust, moisture and temperature. This kind of protection allows electrical equipment in this power range, in this case 75 kW, to function in underground mining at 1200 m below sea level without the use of cabinets to protect the AC drives.

The VACON AC drives have been in operation at the Fazenda Brasileiro gold mine since 2010. Most of the VACON AC drives have IP66/Type 4X enclosures, which provide good protection against dust, moisture and temperature. This kind of protection allows electrical equipment in this power range, in this case 75 kW, to function in underground mining at 1200 m below sea level without the use of cabinets to protect the AC drives.

This case story was originally released before the merger of Vacon and Danfoss Power Electronics was fully completed on 15 May 2015. The contact persons mentioned in the story may have changed. Future case stories on VACON® products will be released on behalf of the new organization – Danfoss Drives, one of the four business segments of the Danfoss Group.