HOISTING TECHNOLOGY
Koepe design allows two conveyances coupled to each other by multiple head ropes counterbalanced by multiple tailropes, and this allows for high payload. However, at depth, it is less economic due to the high cycle fatigue in the head ropes that results in frequent need for replacement. The trade off is at about 1,500 m and in this case the depth was greater than 1,500 m, so a 5.5 m diameter Blair multirope double drum hoist with 6.8 MW installed power option came out on top, which has two ropes per conveyance, again allowing for a large payload but without the rope life issues at depth. FLSmidth has supplied five Blair hoists for the clients’ three shafts which it has built in the last six years. The first was commissioned in late 2015, with two to be commissioned by late 2017 and another two by early 2018.
However, the most recent hoisting innovation from FLSmidth is a new discharge mechanism for ore skips which has the potential to be a game changer for some operations in terms of increasing productivity compared to traditional scroll discharge arrangements. The new skip discharge system is known as the Crank Type Dump Mechanism( CTDM) and the company has applied for a global patent on the design which is currently provisional.
The development began with an approach by a mining client wanting options to optimise their duty cycle. The cycle includes the skip discharge
itself, the time taken for the skip to get to the bottom of the shaft, loading, and returning to the surface. The productivity of the hoisting system relies on the efficient and speedy loading and unloading of the skips. In discharge specifically there are several methods employed, though the most common is a scroll in the discharge arrangement in the head chute of the shaft, where the hoist is slowed significantly and guided along a structural steel channel to allow the skip door to be activated. A second conventional method sees a chute arrangement where the conveyance is brought to a complete stop and a hydraulic mechanism opens the skip. This works well as a method except that the system is
The efficiency of the FLSmidth CTDM aside from its repeatability and the maintainability comes from its speed
Mining Technology
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Mobile Machinery Low-Light Camera System
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AUGUST 2017 | International Mining 29