Instead of traditional scaffolding, which is both costly and time-consuming to erect, Skyriders Access Specialists (Pty) Ltd. combined the use of a hi-tech drone with a specialist abseiling team to provide a unique inspection and maintenance service for Dundee Precious Metals Tsumeb (DPMT) of Namibia.

The remote location, about 430 km north of the capital Windhoek, combined with the height of the structure, meant that traditional scaffolding posed a logistical challenge, Skyriders Marketing Manager Mike Zinn highlights. In January, Skyriders Access Specialists teamed up with Nyeleti Consulting to inspect the smokestack.

The solution was a combination of a drone to inspect the smokestack internally, and rope access to perform all external inspection, as well as core sampling. Based on these collated findings, DPMT put the cleaning project out to tender, which was awarded subsequently to Skyriders.

The Canadian-owned DMPT copper refinery requires periodic inspection of the structural integrity of its smokestack and related areas. “Between our expert technicians and Nyeleti’s engineering experience, we were able to determine precisely what would be needed during the upcoming maintenance period, and draft a detailed report for the client,” Zinn explains.

Due to the potential loss of production incurred by any downtime, Skyriders awaited the planned shut-down specified by DPMT, with the actual maintenance work carried out in May 2018. “Our team received all the necessary permits, and was ready to go as soon as the shutdown commenced. While this mitigated costs for the client, it also created a deadline challenge for the team,” Zinn notes.

The initial inspection revealed ash build-up from free gases inside the smokestack, which can  restrict the airflow necessary to vent the internal gases. This build-up therefore had to be cleared.

The team of six, comprising two Level 3 supervisors and four Level 2 technicians, accessed the top of the smokestack before drilling and placing  anchor points into the structure, from which rigging ropes could be deployed to abseil to the areas that required cleaning.

Now cleaned and with no impeded airflow, the smokestack is ready for a few more years of uninterrupted service life. “Skyriders has a highly satisfied client in DPMT, which indicated its satisfaction at the proactive approach adopted to its specific inspection and maintenance requirements,” Zinn concludes.