With design and contracting capabilities under the same roof, United Mining Services (UMS) is positioned to respond quickly to mining customers’ needs, and has the flexibility to address challenges of any size, big or small. UMS recently delivered a fast, innovative solution for Harmony’s Target 1 gold mine to optimise the shaft’s cooling capability.
Located in the Free State province, the Target 1 shaft is used to transport men, material and rock from surface to 203 level, at a depth of 1 800 metres. A single decline, equipped with a conveyor belt, connects 203 level to 255 level, approximately 2 050 metres below surface.
Prospecting at the mine location dates back to 1890 and the shaft was constructed in the mid-1940s. Consequently, there are no designs available for the shaft, making modifications challenging.
UMS was tasked by the mine to come up with a solution to remove the brattice wall, which allowed the converting of an upcast shaft compartment to downcast to facilitate more cool air entering the shaft from a newly built refrigeration plant at the surface.
Takalani Randima, Takalani Randima, Managing Director of UMS Shaft Sinkers, explains that the rectangular shaft has seven compartments, six of which were used for downcast air flow. In order to convert the seventh compartment to downcast and allow cool air from the new refrigeration plant to pass down through the entire shaft, a portion of the brattice wall in the shaft had to be cut from the surface down to 9 metres below.
After assessing the shaft, UMS identified that there were water and electricity service cables in the way in the brattice wall section. “To access the shaft wall safely without causing damage to the service cables, we designed a ‘skeleton’ that could be attached beneath the skip compartment of the shaft, similar to a cage,” says Len Phillipson, Contracts Manager at UMS.
Phillipson adds that UMS METS designed the skeleton to fit the width of the entire shaft, with the capacity to carry up to five people and equipment, to a maximum weight of eight tonnes. The skeleton was constructed by Harmony’s skip and conveyance workshop, and UMS Shaft Sinkers executed the project. Phillipson says that the mine will be able to use the skeleton for other work that needs to be undertaken on the shaft.
Cutting the wall also proved to be a challenge as it was very old and had no reinforced steel. “During core drilling to check the capacity, we saw that the wall was already cracking. To prevent the wall from falling down, which could have caused irreparable damage to the shaft, we proposed to strap it with steel, and cut it in three sections, each measuring 3 metres long by 2.8 metres wide.
“As there were no drawings of the shaft, we were essentially going in blind, and relied on experience to remove the wall safely,” says Phillipson. “Considering that each wall section weighed approximately 1.6 tonnes, cutting and removing them was not without its risks, but these risk were effectively mitigated and we are pleased to have completed this complex task safely and successfully.”
“Our initial time frame to complete the project was 30 days, but with collaboration between the customer, UMS METS and UMS Shaft Sinkers to solve the challenge, we were able to fast-track it in 19 days,” says Randima.
“The customer had faith in our methodology, and the job was done safely without damaging the shaft’s steelwork. This project demonstrates how UMS can provide quick solutions to mining customers’ challenges by having design, engineering and execution capabilities under one roof.
“This one-stop turnkey service is what makes UMS unique: we have the flexibility to work with customers on projects of all sizes, mobilise quickly, and execute the project efficiently and safely from a commercial and quality perspective, while accommodating the customers’ systems,” notes Randima.
Phillipson adds that owing to the collaboration between UMS and the mine team, the Target mine did not have to stop productivity while the work was carried out on the shaft. As a result, the mine has been able to greatly increase the amount of cold air entering the shaft, and make working underground much cooler and safer.