In 2002 MANAGEM – CMG placed an order with SIEMAG GmbH for the delivery of the mechanical part of a modern skip hoisting installation for the Drâa Lasfar Mine near Marrakech, Morocco. The shaft is designed for a daily capacity of 3,350 tons of polymetallic ore and 600 tons of waste rock.
At the moment, the new hoisting equipment is under erection. The hoisting installation to be supplied by SIEMAG has some specific technical features to meet the conditions prevailing in the mine.
The shaft, with a clear diameter of 3.2m only allows to install a single-compartment skip hoisting installation with counterweight and rope guidance. The skip, designed for a payload of 14.5t is hoisted at a speed of 10.5m/s. The installation is designed to hoist the required capacity of 250t/h ore and waste from a depth of –670.3m. In respect of very high up-cast air velocities in the shaft, friction ropes between skip and counterweight are provided to prevent touching of the hoisting means.
The loading station underground is provided with a measuring pocket to ensure calculated loading of the skip in weight and volume. The swing-out-type skip with maximum cross section can easily be emptied completely. Fixed curves in the unloading station open and close the skip automatically. The unloading bin has a capacity of 35t.
The headframe is designed as a strut frame which is supported by concrete foundations on floor and by an articulated support on top of the guide frame. The guide frame is mounted on shaft girders at pit bank level. In case of overwinding, safety devices are provided in the guide frame.
Two sets of 4-rope sheaves with a diameter of 2.7m are installed on top of the strut frame.
The core of the SIEMAG hoisting installation is the four-rope Koepe-Winder with a diameter of 2.7m, indirectly driven by means of a gearbox and a 900kW DC motor. The winder is equipped with a hydraulically operated disc brake system SIEMAG ST 2 with constant brake force.
A matter of fact in successful receipt of the order was the opportunity of implication of SIEMAG in supporting the customer’s team in planning and designing the installation at a very early stage of the project.
The SIEMAG Project Management, which has proven its competence and reliability in many projects worldwide, guarantees that the customer will receive an efficient hoisting installation within the agreed time schedule.