|Website traffic statistics|
Pages viewed and unique visitors to BMI Online
|Bulk Materials International: For bulk handling and transportation professionals worldwide.
Published: 12 October 2017
Fast-track contract for Lesotho mine
South Africa-based DemcoTECH has reported the delivery a tailings disposal system for Liqhobong Diamond Mine in Lesotho.
Carrying out a “fast track contract”, the materials handling and niche process plant specialist designed and supervised construction and commissioning of a materials handling system for the disposal of dry tailings at the mine in less than a year.
The contract, covering design, engineering, supply, erection and commissioning supervision, was awarded to DemcoTECH by Turnkey Civil Lesotho, on behalf of diamond producer Firestone Diamonds, who holds a 75% interest in Liqhobong, with the remaining 25 % owned by the Government of the Kingdom of Lesotho.
The contract brief called for a system to dispose of 3-4 Mtpa of dry tailings, capable of withstanding the extreme weather and rugged mountainous conditions at high altitude, while, at the same time, being completely re-routable or extendable.
The first route comprised of a downhill conveyor, transfer house and mobile slewable stacker, which became operational in November 2016, just eight months after the contract award in March 2016. The second or main route was operational by February 2017. DemcoTECH said that these tight contract deadlines were met despite the challenges posed by access to and working in the high altitude location of Liqhobong (2,600m above sea level), the requirement for special engineering solutions, inclement weather, and the demanding terrain.
DemcoTECH said it designed advanced features into the system, including a belt storage system, enabling the entire system to be extended by 60m within a 24-hour time period. The tailings disposal system consists of a fixed downhill conveyor rated at 700 tph, which is equipped with a regenerative electric-hydraulic braking system to prevent the conveyor from running away. In addition, a 20m mobile slewable emergency boom is part of the standby route, while other components of the system include a 120m-long retractable conveyor, a 450m-long extendable conveyor (inclusive of the belt storage system), and a slewable 15m mobile stacker that is four-wheel driven. This allows the machine to be self-propelled.
The ability of the 450m-long extendable conveyor’s belt storage system to extend the conveyor by 60m increments reduces the number of belt splices, thereby reducing the standing time when the head station, also mounted on a pontoon, is pulled for repositioning using mobile equipment such as a front-end loader.
The head of the conveyor feeds onto a mobile, self-propelling slewable stacker, mounted on rubber tyres and equipped with hydraulic drives, which can be repositioned by remote control.