HOISTING TECHNOLOGY
in quite an inaccessible area of the shaft and hydraulics need regular maintenance so there can be reliability issues. These hydraulic systems can be large and complex and therefore costly.
In response to the client query, FLSmidth Mechanical Design Engineer – Mine Shaft Systems, Francois Koekemoer came up with the idea of using a crank type gearbox based system that uses an reciprocal crank motion. A gear-motor mechanism performs the function of discharging material and replaces the traditional fixed scroll system which has subsequent longer cycle times. The system operates whereby the skip rapidly moves into the dump position and engages the CTDM, then a command is given to open and discharge material, and the cycle is completed by the closing command and the skip returns to shaft bottom. The method gives a constant and repeatable motion every time. Once the conveyance is chaired, the mechanical duty is the same on each pass and there are no hydraulics involved. The velocity and torque profiles generated by the crank motion best suits applications where opening and closing of large inertia skips is required.
FLSmidth added that the components are largely off the shelf, not bespoke, such as a standard motor and gearbox, resulting in a simple robust system.
The efficiency of the CTDM aside from its repeatability and the maintainability comes from its speed. In the conventional scroll system, the skip has to be slowed to so called creep speed for a longer duration discharge. Terence Osborn, FLSmidth Commercial Manager, Minerals, Sub- Saharan Africa told IM:“ Our study showed that using the CTDM, their production duty cycle would reduce from 156 seconds to 141 seconds which represents a production increase of 11 %, translated to 2.5 additional cycles per hour so the upside is significant. The payback for a retrofit installation is expected to be less than six months.” The initial investment for this solution is small compared to overall shaft construction costs. The cost of the CTDM is similar to the hydraulic solution cost but the long term reliability is better meaning maintenance is less frequent and less complex. The advantages of the CTDM are summarised as follows: n Gate opening time can be increased
The innovative OLKO-Maschinentechnik mobile, truck-mounted, shaft winch can be used for a single-drum hoisting installation, as an inspection system, auxiliary system or rescue system
n Hoist motor is not subjected to dynamic torque caused by scroll profile n Guide plates in the bail are static during discharge n Dump roller forces are reduced n Customised retrofit installations n Reduced head room required with new head gear design FLSmidth does point out that not all mines have such a capacity constraint and need to increase their production rate, but it does happen in the early years of production, when operations are trying to reach capacity and the method locked in at feasibility is not allowing them to maximise production. In terms of the wider market, about 80 % of mines with a skip system use a conventional scroll in method so the potential is significant globally.
OLKO delivers mobile shaft hoist innovation
Since 2012, OLKO-Maschinentechnik GmbH, the German supplier of shaft hoisting technology, has been a member of the Thyssen Schachtbau
Group. OLKO was founded in 1989 as an engineering consultancy and developed into an international supplier of shaft hoisting equipment. OLKO offers winders and winches of different types and sizes. From“ smaller” applications like stage or emergency winders up to large“ high-end” winders of all kinds, OLKO can offer the complete range of shaft hoisting equipment.“ In combination with its mother company Thyssen Schachtbau and its world-wide affiliates, such as Australia-based Byrnecut, a complete mine could be offered from one source and world-wide service is ensured.”
After having supplied several double drum and friction winders in 2016, OLKO is currently busy in executing a project for two double drum Blair winders with a diameter of more than 6 m and a motor power of more than 9 MW. Furthermore OLKO is currently performing the last steps of final commissioning of a newly developed mobile shaft winch, which was firstly presented to potential clients on 29 and 30 June 2017 during the Excamine Days, OLKO’ s internal exhibition. The mobile, truck-mounted shaft winch can be used for a single-drum hoisting installation, as an inspection system, auxiliary system or rescue system, depending on the specific application. The provided kibble, which is constantly carried on the vehicle and equipped with a signalling system, allows voice communication between the personnel in the kibble and the winder operator in the machine operator cab.
The mobile truck-mounted shaft winch is in compliance with the Road Traffic Licensing Regulations, the German mining regulations( TAS) as well as DIN 15018 / 13300, DIN 18800 / EN 1090 and DIN 4118. Further approvals for other countries can be obtained upon request. The provisions of the Mining Ordinance for electrical systems and shaft inspection are also met.
“ The winch can optionally be operated via the rope pulley mounted on the boom end or via an external rope pulley mounted in the shaft frame. The kibble or cage for the transport of persons or material is fixed to a rope attachment at the end of the hoisting rope. The winch equipment is mounted onto a five-axle truck chassis of the latest generation.” The vehicle is equipped with a six cylinder four-stroke diesel motor with a performance of 331 kW / 450 hp. The rotating
30 International Mining | AUGUST 2017