Tag Archives: diamond mine

Emesent’s Hovermap aids ore pass decision making at Petra’s Finsch diamond mine

Highly accurate point cloud data sets from a Hovermap scan have allowed Petra Diamonds’ Finsch mine engineers to “see” the condition of ore passes for the first time and avoid an estimated five months and R5 million ($350,000) in remediation, Emesent says.

Finsch, in South Africa’s Northern Cape, uses ore passes and underground silos to transfer ore between levels or to redirect ore for load and haul to the surface. Blockages, hang-ups, overbreak or scaling can impact the structural integrity and result in extended downtime and significant remediation costs. Accurate imagery enables mine engineers to gauge the integrity of ore passes and plan timely and cost-effective remediation programs, according to Emesent.

Historically, however, scanning and mapping inaccessible shafts and voids has been a challenge for Petra.

The company’s management sought a means of obtaining accurate visualisations of underground voids, quickly and cost effectively, without endangering the safety of Petra personnel or contractors, Emesent says.

Petra management trialled the Hovermap multiple data capture methods with Emesent partner, Dwyka Mining Services, contracted to carry out multiple scans of an indoor stockpile, ore passes and vertical shafts, and a series of access tunnels and ramps.

Hovermap is a drone autonomy and LiDAR mapping payload. It uses the LiDAR data and advanced algorithms on-board, in real time, to provide reliable and accurate localisation and navigation without the need for GPS.

Dwyka spent a day on-site conducting a series of scans using Hovermap mounted to vehicles, a DJI drone, or lowered in a protective cage. Dwyka delivered point cloud data sets for Petra’s survey team to geo-reference and analyse, within 24 hours. It also provided visualisations of the ore passes, enabling the mine engineers to ‘see’ the condition of orepasses for the first time, Emesent said.

Alex Holder, Group Planning and Projects Lead at Petra Diamonds, explained: “We lowered Hovermap down ore passes, flew the drone into draw points and even scanned our shaft and ramps by fixing the scanner to one of our vehicles. The visualisation delivered exceeded all our expectations. The data captured in one ore pass saved us significant time and effort by confirming it was irreparable. That saved us millions.”

Using Hovermap led to an immediate decision to abandon plans to expend resources remediating a compromised ore shaft. This decision saved Petra an estimated five months and R5 million.

Heinrich Westermann, Mining Engineer at Petra Diamonds, said: “The ability to power and switch the Hovermap payload between the various applications meant that we were able to scan a considerable amount of the mine in one shift. Generally, this was either impossible and, if it were possible, it would take weeks to collect those datasets and months to see the final visuals.”

The data collected by Hovermap has become the basis of a data library for the site. It is augmented regularly and used to inform operational decision making by Petra’s mine planning and survey teams, according to Emesent.

Petra intends to deploy Hovermap scanning technology to map inaccessible locations at its other sites across Africa, Emesent says.

Kwatani problem solving doubles diamond mine’s screening feed rate

Kwatani says it has helped a South Africa diamond operation double the feed rate of its degrit screen through the use of one of its customised solutions.

The customer was operating several multi-slope screens to dewater product between 0.8 mm and 5 mm in size, before it was treated by dense medium separation (DMS). However, the screens were causing a severe carry-over of water onto the conveyor belt to the DMS, according to the South Africa-based OEM.

“The feed rate on each screen was being limited to about 250 t/h,” Kwatani CEO, Kim Schoepflin, said. “We tackled this by designing and manufacturing a customised multi-slope screening machine to fit the customer’s existing footprint.”

Schoepflin said Kwatani’s replacement was able to double the feed rate to about 500 t/h, with minimal water carry-over.

As a result of the success of this unit, the customer requested Kwatani to replace the whole bank of screens, it said.

In another contract, a customer asked for assistance with underperforming screens that could not deliver the original design parameters. They also wanted to increase the tonnage throughput by 17%, according to the company.

“We conducted a careful evaluation in collaboration with the customer, and came up with an innovative and economical solution,” Schoepflin said. “Simply replacing the existing screens with Kwatani’s new larger screens would have been costly and time consuming, so we decided instead to replace the screen’s existing gearboxes.”

The replacement gearboxes delivered greater vibration, but without exceeding the output torque the existing motors driving the gearboxes could provide.

“Drawing from our portfolio of locally designed and manufactured exciter gearboxes, we were able to implement this solution very quickly,” she said. “The two new exciter gearboxes were delivered to site and were in operation within two weeks – successfully and immediately increasing the screen’s throughput.”

The benefits to the customer did not stop there, according to Schoepflin. The newly optimised operating parameters meant the material bed depth was lower, so the drive motors drew a lower amperage and reduced the cost of power consumed.

“Our customised screening and feeding solutions – developed by our in-house team of experienced mechanical engineers and metallurgists – are based on consultation with each customer,” she explained. “The result is a design that delivers the optimal processing performance and tonnage at the lowest cost of ownership.”