Five Liebherr 1250 HC tower cranes are being used at two mining projects in the Atacama Desert in Chile. These large 40 and 50-t versions have one of the highest lifting capacities of any tower cranes in Latin America. Two 1250 HC 40 Litronic tower cranes have been mounted on foundation anchors at the Minera Escondida copper mine which is at an altitude of 3,100 m above sea level. Three more 1250 HC tower cranes are in use at the Minera Sierra Gorda copper mine – one seen here.
During the initial phase the Escondida tower cranes will be used for extension work and to build the mine infrastructure. Both machines have a working radius of 52.0 m which covers the required working area and have hook heights of 40 m and 52 m. During the construction phase they handle loads of up to 20 t.
After the construction phase has been completed the two Liebherr tower cranes will be used for maintenance purposes. Their planned service life is around 25 years. Liebherr reports that reliability and long term availability of spare parts were among the main factors for selecting Liebherr tower cranes for this long-term project.
Two of the Sierra Gorda cranes are the 50-t version and the third is the 40-t version. All three cranes have been mounted on foundation anchors and erected in similar configurations.
The 1250 HC 40 reaches a hook height of 34.9 m and a working radius of 51.9 m. The two 1250 HC 50 are configured with hook heights of 68.6 and 69.6 m and each has a working radius of 38.8 m.
During the construction phase the cranes are used as classic tower cranes for effective load handling for the assembly of tanks. The construction of the tanks, each with a capacity of 300 m², is scheduled to take one year. During this process loads of 14-17 t per component will be handled.
In the long term all three cranes will be used as maintenance cranes in the mine. One 1250 HC will be used to support maintenance work on the flotation cells. The two others will help with service and maintenance work at the ball mills.
The extreme geographical and climatic conditions not only present challenges to the workforce but also to the crane equipment. The high temperature differences of up to 40°C between night and day and the dust created by the arid desert climate produce extraordinary stresses.
In addition Chile is one of the most earthquake-prone countries on Earth where earthquakes up to a magnitude of 5 are by no means a rarity. This means that all the cranes must comply with a Chilean standard which ensures that they are resistant to earthquakes. Since 2010 several Liebherr EC-H and HC tower cranes have been used successfully in mining projects in Chile and Peru.
