20% power savings, 0.5% higher recovery at Bucim mine

Success from 2005 onwards

Bucim is the largest open-pit copper mine in Macedonia, located in the southeastern part of the country, about 130 km from the capital of Skopje. Although the mine has been operational since 1978, it closed for a short time after being privatized in 2000. In 2005, the company Soleway purchased the mine and has turned it into one of the most successful companies today in Macedonia, operating at an outstanding 98% efficiency in overall equipment effectiveness.

The copper concentrate from the mine is of high quality without significant impurities, and is therefore sought after by European smelters. The mine produces 4.5 million tonnes of ore per year with an annual capacity of 2,000 tonnes of cathode copper.

The need for a stable process

In 2014, the mine experienced serious control issues with its hydrocyclone pump, resulting in dry running, inconsistent feed and low throughput.

Bucim aimed to stabilize its flotation process, increase recovery, reduce power consumption and prolong the wear life of its pumps. The mine knew that the pumps were at the heart of its flotation process. Choosing a more reliable and efficient pump would enable the entire process to be more efficient.

Based on a long-existing relationship, Bucim turned to Metso to ask for a solution to this problem.

“We have a very good relationship and 30 years of experience working with Metso, whose people always have a good and professional attitude”, explains Zivko Gocev, Mining mananger, Bucim.

Selecting the best pump for the job

Metso analyzed the process to determine the right pump size to maximize wear life and to operate at the highest efficiency. The MDM300 was selected, since its hydraulic design limits the inlet velocity, enabling operation at the best efficiency point. Its high-performance materials provide resistance against abrasive, corrosive and erosive slurries, and its low-noise design easily meets the decibel level requirements.

The MDM300 pump was packaged along with a variable frequency converter and successfully installed in April 2015. This enabled the mine to regulate the pump rotational speed and control the inlet tank level, stabilizing the process and eliminating the dry running.

By having improved control over the process, the mine achieved better separation and an impressive 0.5% increase in metal recovery rate. Since dry running was no longer an issue, pump wear life improved by 10% and overall power savings of 20%. Based on these excellent results, the mine decided to install a second MDM300 in April 2017.

“We are extremely happy with the Metso package, which combines exemplary service and quality products. We have now operated the MDM300 pump for over 8,000 hours, without incident, and achieved a 20% power saving. This product offers a good design, easy wear adjustments and maintenance. We’re looking forward to continue reducing our total operating costs.” Zivko Gocev continues.

Closed loop environmental management control system

The water used at the Bucim mine is in a closed loop, to be reused and prevented from being released outside of the mine. Once the water is used in the process, it is led to the tailings dam, where it goes through a settlement process for cleaning and then is recirculated back into the process. The tailings dam is closely monitored. Furthermore, the stability of the tailings dam is externally reviewed on an annual basis. This tailings dam surprisingly contains fish in the water with a very clean PH average of 9.5–10.

The dam walls are built of the sand to a certain height using hydrocyclones. Once that height is reached, 25 cm of soil is spread on top and Acacia and Cypress trees are planted to rehabilitate the land. To date, this successful project is attracting visitors from other mines to take note.

Fully committed to social responsibility

Since its start in 1978, the Bucim mine has been fully committed to its social responsibilities in the region. The mine donates money each month to maintain roads, to support monasteries, educational and sports facilities, to provide medical equipment for hospitals and nurseries, and to promote cultural activities. With 700 employees, the mine is also the largest employer in the region.

Metso mill discharge pumps

Metso MD series mill discharge pumps are designed using our long history, extensive know-how and experience working with grinding mill circuits in a wide variety of mineral processing applications around the world. Our MDM hard metal and MDR rubber-lined slurry pumps ensure sustained performance, with maximized time between rebuilds.

The MD pump has a modular design with a double adjustable feature that maintains pump performance and efficiency due to close tolerance. The interchangeability of all metal and rubber parts suit all duty parameters.