Holcim Schweiz hit a milestone recently with the aerial drone programme at its Siggenthal cement plant. The project with Voliro, a Switzerland-based technology start-up, has started to use multi-rotor drones to conduct official measurement flights. They used them to take measurements to determine the steel wall thicknesses of the cement kiln and the cyclone preheater. The work has been part of Holcim’s ‘Plants of Tomorrow’ industrial automation plan with unmanned aerial vehicles (UAV). Key features of the particular drones being used are that they can be rotated around all axes by a special rotor system and can even fly upside down.
Holcim has been using drones in and around cement plants for a few years now. When it launched the Plants of Tomorrow plan in 2019, Switzerland-based drone supplier Flyability said that the cement company had chosen its Elios 2 model to perform confined space inspection. Earlier in 2017 another supplier, SenseFly, said that LafargeHolcim Tanzania had been using its fixed-wing products. Holcim is also far from alone in its use of drones. A few examples among many include Cemex USA’s work with Kespry earlier in 2021, HeidelbergCement’s work in North America and Germany in 2020 and 2021 and Votorantim’s testing at its Córdoba and Niebla plants in Spain back in late 2015.
UAV usage by armed forces dates back to examples like unmanned incendiary balloons being deployed in the 19th century to Azerbaijan’s reported decisive use of drones in its war against Armenia in late 2020. The current era of industrial UAVs began after 2000 when governments starting issuing civilian permits, miniaturisation occurred and improvements in cameras, sensors and computing power followed. For the mineral processing sector the trend started with drones being used for stockpile management and quarry surveying. At present this is the main area that UAVs are used for by the sector, often coupled with photogrammetry techniques. CalPortland’s Adam Chapman’s paper at the 2021 IEEE-IAS/PCA Virtual Cement Conference described one company’s use of UAVs in the cement industry since 2016, looking at licensing, cost, quality of data, drone technology, fleet management and field experiences.
More recently though, tests of drones used to survey cement plant buildings and structures have started being publicised such as Holcim’s work at Siggenthal. A presentation by consultant John Kline and Chris Place of Exelon Clearsight summarised the use of drones for structural inspection at cement plants at the Global CemProducer 3 webinar in January 2021. The key benefits they promoted of using an UAV in this way were: improved safety because workers have reduced risk from climbing, working at height or in confined spaces; less time to conduct a survey; higher resolution photographs and video; better coverage through grid method surveying; and an overall lower cost. However, on that last point, other commentators have noted that market-leading drones for surveying are relatively expensive and easy to damage. Drones have since been used to start going inside structures at cement plants with Kline demonstrating their use to inspect the condition of refractory within the cooler, kiln, pre-heater and cyclone of a production line at the Global CemProducer 2 webinar in July 2020. HeidelbergCement has also been doing similar things, with an inspection trial using a drone of the kiln at the Schelklingen plant in Germany during the 2021 maintenance shutdown period at the site.
So far the use of drones by the cement industry has mostly been in a surveying or inspection capacity. Given the short time that UAVs have been used like this there is likely to be scope for lots more development both within existing fields and new ones as the sector works out how best the technology can be used. One application we couldn’t find in the research for this short article was the use of drones for security and surveillance tasks at cement plants and quarries although this may be happening already. However, there could be a more active role for drones if or when a company finds a way for them to start making basic repairs or carrying out simple maintenance in those hard to reach areas that drones excel at accessing. Research examples exist of UAVs being used to spray concrete or repair materials onto minor defects in concrete structures. Yet considerable challenges face these kinds of applications such as the weight of a loaded multi-rotor drone or damage from rebound. Before we all get too worried about drones replacing our jobs though it is worth considering that Amazon’s plan to deliver packages by UAV was first announced in 2013 and it still hasn’t happened yet. It may yet, but for now in most situations humans remain cheaper and more practical than robots or drones.