Mining engineering turnkey solutions provider United Mining Services (UMS) Group has successfully completed the delivery of a fast, innovative solution for gold miner Harmony Gold’s Target 1 mine, which will optimise the shaft’s cooling capability.

The Target 1 shaft is used to transport people, material and rock from the surface to 203 Level, at a depth of 1 800 m.

The project entailed the removal of the brattice in the shaft, which allowed for the upcast shaft compartment to be converted to a downcast compartment to facilitate the flow of more cool air entering the shaft from the newly built refrigeration plant at the surface.

To access the shaft wall safely and without causing damage to the water and service cables in the shaft wall, UMS Mining Engineering Technical Services designed a ‘skeleton’ that could be attached beneath the skip compartment of the shaft.

UMS Shaft Sinkers MD Takalani Randima explains that the rectangular shaft has seven compartments, six of which were used for downcast air flow.

“To convert the seventh compartment to downcast and allow for cool air from the new refrigeration plant to pass down through the entire shaft, a portion of the brattice in the shaft had to be cut from the surface down to nine metres below,” she explains.

“The skeleton is similar to a cage, with the capacity to carry up to five people and equipment, to a maximum weight of 8 t,” adds UMS contracts manager Len Phillipson.

The skeleton was constructed by Harmony’s skip and conveyance workshop, with UMS Shaft Sinkers executing the project.

Phillipson says the mine can use the skeleton for other shaft work in the future.

“As there were no drawings of the shaft, we were essentially going in blind, and relied on experience to remove the brattice safely,” he notes.

Each wall section weighed about 1.6 t, and while cutting and removing them was not without risk, it was effectively mitigated by UMS.

“We are pleased to have completed this complex task safely and successfully,” says Randima.

Safety Stresses

She stresses that most of mining incidents and fatal accidents can be attributed to a lack of, or inadequate, mining infrastructure maintenance.

“There are several factors affecting the current state of the mining sector, such as a lack of adequate skills, owing to inadequate skills transfer programmes,” she says.

The qualified persons appointed often do not have the practical knowledge to identify the crucial areas that require maintenance in the mine.

Additionally, the industry requires a mindset shift, as mining houses need to acknowledge that, for a shaft to operate safely to its full designed capacity, it requires properly scheduled maintenance.

“Production should not be placed ahead of safety,” adds Phillipson.

Exploring Technology

Randima explains that UMS continues to use and explore new technologies, including remote-controlled machines in a shaft that eliminate the human-machine interface.

This technology has noticeably reduced accidents at the Karowe project, in Botswana, where a drilling machine from remote-controlled demolition robot manufacturer Brokk, as well as a remote-operated jumbo drill rig, are being supplied by UMS.

UMS is also using iPad and relevant technologies to promote real-time communication underground.

It can also provide three-dimensional scans and drone technology to scan for underground infrastructure of an ore pass when partnering with another company.

“This has been successfully used for one of UMS’ projects in the platinum belt,” Randima enthuses.

Further, the company can design shaft centre towers to allow for shaft pillar extraction. This design has been successfully used for a project where the existing shaft steel could be saved from total removal and replacement.

Randima concludes that this solution saved time and allowed for the shaft to stay in production while the steel was modified and suspended.