Capital Equipment News April 2018

MINING NEWS

Kwatani takes heavy screen design to new heights

Spartan-based vibrating screen spe- cialist Kwatani is building one of its strongest and heaviest screens yet, to undertake punishing duties at a South African iron ore mine. The 54 tonne (t) scalping screen – measuring over 10 m in length and with a 3,7 m width – is a single-line unit that will handle about 7 000 t of run-of-mine iron ore per hour. It will take feed from a primary crusher with a top size of 400 mm, although the dimension of the boulders may still be up to 800 mm long. “The run-of-mine feed will place tremendous load on the screen, particularly due to the impact and weight of the oversize rocks,” says Kwatani CEO Kim Schoepflin. “Significantly, a large portion of the material – as much as 50% of the feed – will move over the full length of the screen without passing through the apertures, so the screen must effectively ‘convey’ these heavy boulders without incurring damage.” This also means that the bed depth will be relatively high, requiring the design to accommodate a bed of about 800 mm of material on the feed end and about 500 mm on the discharge The conversion of a JCB JS205 excavator into a drilling rig has produced a machine that rewrites the efficiency, productivity and safety rulebooks. The innovation, which stems from a partnership between three specialist companies – Kemach Equipment, Liyema Drilling and Integrated Air Solutions, combines a premium excavator with a premium compressor and a locally designed, tailor-made drilling tower that conforms to all OEM specifications. To achieve the seamless 3-in-1 integration, the companies worked closely on a solution, dedicating their respective technical expertise. Basie Roelofse and his team from Liyema Drilling, a Level 2 BBBEE 87,5% black-owned company, was responsible for converting the JS205 excavator into a drilling machine. Basie explains that mines are under constant pressure to improve efficiency, production and safety. “To remain competitive and secure contracts drilling machines must be fast, efficient, productive Taking drilling to the next level

One of the Kwatani scalper screens during manufacture.

end. Iron ore is a heavy material, so a bulk density factor of 2,5 has been applied to the design specifications. Vibrating with a stroke that applies around five times the gravitational acceleration (5G’s) on the material, the mass of the rocks is effectively increased by five times, according to Kwatani’s chief operating officer Kenny Mayhew-Ridgers. “This places a very high requirement on the machine’s technical specifications and durability, so the mine has been very careful to choose a supplier that they trust completely to design and

manufacture a unit of this capacity,” says Mayhew-Ridgers. “Even the panels had to be designed with internal structures so they could withstand the magnitude of these forces.” Schoepflin emphasises that the unit’s single-line status makes it a key item of equipment on site, with several parts of the process plant heavily reli- ant on its throughput. “It is, therefore, vital that the screen runs reliably and continuously, as any stoppage will in turn disrupt the whole plant,” she says. “Uptime is an absolute non-negotia- ble.” b

and equally important, safe. It’s not about how fast you drill, it’s about the speed of the set-up, that is, how fast you can retrieve and move to the next hole. We are therefore relentless in our search to find ways to improve and innovate machines to maximise our set-up time.” Liyema Drilling

Integrated Air Solutions customised the ELGi diesel compressor which replaces the counter-weight at the rear of the JCB JS 205 drill.

is currently operating the JS205 drilling machine at Kangala Coal Mine in Delmas. “The JS205 has reduced our set-up time from seven minutes to an astounding 11 seconds, which enables us to complete between 450 m to 750 m in a single 12-hour shift,” says Basie. “With the capacity to drill 100 m more per day, the fully integrated solution has enabled us to improve our production by 80 hours in one month. In addition to vastly improved productivity, we

also burn less fuel and the operator is less fatigued, which has an important safety implication.” Basie also confirms that they can drill from a 114 mm to a 171 mm size hole. With a simple equipment change (drill rod and base on floor), the rig can reach a hole size of up to 205 mm. He adds that the rig delivers a penetration rate of between 65 m and 85 m per hour, which is more than double the standard rate of approximately 28 m. b

CAPITAL EQUIPMENT NEWS APRIL 2018 39