The perfect synergy between drone technology and traditional rope access was demonstrated at a recent inspection project undertaken by Skyriders at one of the country’s oldest power stations, located in Mpumalanga. The fast-track project was undertaken in conjunction with partner company Nyeleti Consulting (Pty) Ltd.

The two-part project involved the inspection of two 155-m-high smokestacks. The external inspection component was carried out by a two-person team deploying hi-tech drones fitted with high-definition 4K and thermal cameras.

The thermal imaging was carried out very early in the morning, before the sun’s heat could have an impact on the smokestacks. This was necessary to identify any hotspots that could indicate areas where the internal brick lining of the concrete wind shield had deteriorated, Skyriders Marketing Manager Mike Zinn comments.

In the second part of the project, a two-person rope access team took core samples from the two smokestacks. This involved drilling 100-mm-deep holes into the concrete, and extracting the samples to be submitted for laboratory testing for compression strength and carbonation, among others.

“While a good visual inspection is essential, and can provide a wealth of information, it is equally important for an engineer to understand the ‘health’ of the concrete itself, as well as the rebar or reinforcing steel. Both these components give a good overview of the true condition of the structures,” Zinn explains.

After the core samples have been physically cut out, the subsequent holes are patched with an approved patching material to ensure the integrity of the structure. Following the receipt of the laboratory results, a detailed report was submitted to the client, highlighting any issues that may require attention.

“Depending on the findings, we could very well be contracted to carry out additional maintenance or repair work in the near future,” Zinn adds. For this particular project, Skyriders called on the particular expertise of Nyeleti Consulting, which has the only CICIND (International Committee on Industrial Chimneys) accredited engineer in South Africa, and an expert on industrial smokestacks and chimneys.