Tag Archives: diamond

Botswana diamond mine feels the impact of Weba Chute Systems custom solution

Faced with a challenge of large rocks in the run-of-mine (ROM) feed regularly damaging main support structures, chutes and a grizzly feeder, a diamond mine in Botswana reached out to Weba Chute Systems to design a solution to overcome this costly challenge, which included major safety hazards.

According to Hilton Buys, Regional Manager at Weba Chute Systems, the mine’s existing chutes at the ROM section were cracking and breaking under the barrage of heavy kimberlite rocks measuring up to 1 m in diameter.

“Even the robust grizzly feeder could not withstand the impact of these rocks, which were free-falling about two metres from an apron feeder before contact,” Buys said. “Apart from the costs incurred by this damage, the transfer points were posing a significant safety hazard to mine employees.”

The solution – designed and manufactured at Weba Chute Systems’ Wadeville facility – was a special four-tonne swing door in a discharge chute, feeding from the apron feeder to the grizzly. The heavy, fabricated door is strong enough to withstand the impact while absorbing the energy of the falling rocks before allowing them to drop onto the loading section of the grizzly. The feed can then move in a more controlled manner over the grizzly into the crusher below.

“The key principle was for the door not to give way easily, thereby reducing the velocity and momentum of the large chunks,” Buys said.

There was also a design requirement to accommodate the movement of smaller rocks. This was dealt with through the addition of a second door, to also ease these rocks onto the grizzly to ensure a more gradual feed into the crusher feed chute. The success of the design, which is based on the Weba Chute Systems principle of controlled flow, has been demonstrated in the chute’s ability to operate with very little maintenance, he says. The only components needing regular attention are chute lips and swing door rails.

“We also included some specific design elements in the crusher feed chute, by installing impact rubbers,” Buys said. “Any rocks that may diverge from the main flow stream will then strike this rubber, minimising the vibration and impact on the body of the chute and are still able to drop gently into the crusher.”

Following on the success of this design, the solution was repeated at other customers’ sites, including mines in the Northern Cape which experienced similar challenges.

Kwatani registers global mining demand for vibrating equipment

Kwatani’s vibrating screens and feeders are continuing to find a market in the mining industry, with a number of orders recently secured from diamond, coal, zinc and platinum operations.

The company’s custom engineered products are now in some of the world’s largest mines, and many customers have standardised on their screens to ensure lowest cost of ownership and high performance, according to General Manager, Sales and Service, Jan Schoepflin.

“While our base and core market are in Africa, the global demand for Kwatani products has grown rapidly. A leading diamond mining company in Russia is very pleased with Kwatani screens at their newest operation and specified Kwatani for future projects,” Schoepflin says.

In another order from a large diamond operation, this time in South Africa, the customer replaced the last of its competitor screens with a Kwatani unit. Schoepflin says this is because it has enjoyed years without unplanned stoppages by using Kwatani screens.

At a local brownfield diamond expansion project, the company’s multi-slope banana screens were matched to the available plant footprint, raising throughput from 250 t/h to 500 t/h and, later, breaking the mine’s tonnage record.

“While screening in heavy minerals is Kwatani’s stronghold, the company has moved extensively into coal, supplying the country’s (South Africa’s) leading coal producer with no fewer than 45 items of large screening equipment, including out-sized 4.3-m-wide units,” the company said.

Other recent coal-related orders included run-of-mine screens for a medium-sized coal mine in Mpumalanga, South Africa. Again, competitor equipment was replaced by custom designed screens with optimised deck angles, which significantly increased tonnage, according to the company.

“The positive results achieved with the Kwatani equipment also led to additional orders for the mine’s expansion,” Kwatani said.

For world largest zinc mine, Kwatani was contracted to supply all the screens, while, at Africa’s largest iron ore mine, the company recently completed two projects, renewing existing equipment with updated solutions and replacing 24 items of competitor equipment.

“The platinum sector is also keeping Kwatani busy, not just in South Africa but over the border in Zimbabwe too,” Kwatani says. A recent turnkey solution focused on platinum by-product chromite, where the company supplied a complete solution which included feeder, dryer and screen to treat chromite of 45 micron size at 15 t/h.

Schoepflin said: “Our screens have been a popular choice for modular gold plants going to West Africa as well as Central and South America. We also supplied to two of Africa’s largest copper producers in Zambia, to a tanzanite producer in Tanzania, and repeat orders to a manganese mine in Ghana.”