C-DRONE GUIDE · 25 AUGUST 2026
Bulk Coal and Ore Stockpiles: Drone Thermal Monitoring and Volume Measurement, Method and Price
A coal pile stored in the open air at a port terminal can smoulder at its core with no smoke betraying it at the surface — spontaneous coal combustion first progresses through slow, invisible oxidation before it breaks through. On these solid bulk yards feeding steelmaking, cement plants and thermal power stations, the operator must both monitor this diffuse thermal risk and keep the stockpile's real volume up to date against the customs or accounting register. The drone answers both needs in a single campaign, through thermography and photogrammetry. Here is the method and the prices.
Published on 25 August 2026, reviewed on 25 August 2026 — regulations in force as of August 2026.
An open-air industrial bulk yard, under its own ICPE heading
France's major maritime ports receive and store, on open-air yards spanning several hectares, solid raw materials in bulk : coal and coke destined for steelmaking or thermal power stations, iron ore, biomass (wood chips, pellets) for industrial boiler plants. Unlike grain stored in a closed silo — see our guide to grain silo drone thermography — these materials are piled directly on paved or stabilised areas, sheltered by no building.
Storing coal, coke, lignite and bituminous matter falls under ICPE heading n° 4801, under the declaration regime above a stored-quantity threshold ; the largest operators — big coal terminals, coking plants integrated into a steelworks — may fall under a stricter regime depending on the tonnage. This classification frames the operator's requirements (runoff water containment, dust control, firefighting resources) ; it in no way exempts regular physical monitoring of the piles themselves, distinct from the container tracking already covered in our guide to drone container yard inventory.
Spontaneous coal combustion: a heat risk that smoulders below the surface
Coal stored in piles oxidises slowly on contact with air, an exothermic reaction that releases heat which is hard to dissipate at the core of a large stockpile : the taller and more compact the pile, the less heat escapes through natural convection, and the greater the risk of thermal runaway — self-heating. Past a certain threshold, generally between 80 and 120 °C depending on the coal's nature and moisture content, the reaction accelerates on its own up to ignition : by the time smoke becomes visible at the surface, the seat of the fire has already been smouldering underneath for several days.
A visual surface inspection detects none of this underground heating ; a study by Xiaoyuan He, Xingke Yang, Zheng Luo and Tao Guan, published in 2020 in Scientific Reports, applied airborne drone thermal infrared imaging to mapping coal fire zones at the Huojitu mining site in China, highlighting the superior resolution and availability of this approach compared with satellite imagery for precisely locating active fire seats (see the study on Google Scholar). The same principle, transposed to a bulk coal pile at a port terminal : a regular thermal pass over the stockpile's surface spots a hot spot while it is still localised, allowing action — aerating the pile, a localised turn-over, targeted watering — before it degenerates into a stockpile fire, a costly incident that takes part of the terminal out of service.
Regular pile volume measurement: an independent physical inventory
Beyond the thermal risk, the operator of a solid bulk yard must continuously track the actual volume of each pile — coal, coke, ore — against the inbound and outbound movements recorded by the terminal's operating system, on the same principle as stockpile volume measurement in quarries and civil works or the wood chip tracking detailed in our guide to wood energy storage. A drone photogrammetric survey recalculates this volume in a campaign of a few dozen minutes, with enough precision to reconcile a customs register, a port handling invoice or a year-end accounting inventory, without tying up any equipment or interrupting loader traffic on the yard.
Repeated at regular intervals — monthly, or at every major vessel rotation — this independent measurement also flags an unexplained discrepancy between the physical and theoretical stock, useful in a dispute with a customer or charterer over the quantity delivered.
Method, flight framework and price
The mission is coordinated with the terminal operator and, depending on the port's setup, with the harbour master's office : access badge, safety briefing, compliance with the traffic circuits for handling equipment and active crane zones. The drone flies over the stockyards under the open category, subject to a prior declaration if the terminal borders a populated urban or port area, common for commercial ports located within a built-up area.
The deliverable pairs a thermal pass over the surface of the piles (hot-spot location, mapping of areas to monitor) with a photogrammetric survey giving the volume of each stockpile, delivered as an orthophoto and a volume table usable by the operations department. 2026 prices (excl. VAT) : €800 to €1,800 for a thermal-only campaign on a typically sized yard, €1,500 to €3,000 for a combined thermography-and-volume campaign across several piles ; a monthly or quarterly follow-up contract, on the same flight plan, is negotiated at a discounted rate compared with the initial campaign. Our thermal imaging drone page presents the service; request a quote stating the stored material (coal, coke, ore, biomass), the yard's surface area and the desired frequency.
Frequently asked questions about drone monitoring of a solid bulk stockpile
Can the drone detect a fire already active deep inside the pile? The thermal pass spots the anomaly at the surface as soon as it starts to show through ; a deep seat still fully insulated by the mass of the pile can stay invisible until the heat rises far enough. That is why regular monitoring, not a one-off check, remains the best prevention.
Does this service replace fixed temperature probes? No : where they exist, probes driven into the pile give a continuous point measurement at one precise spot ; the drone adds a complete, regular surface view, complementary to them and particularly useful on the parts of the pile with no instrumentation.
Who commissions this mission? The port terminal operator (handling operator, logistics subsidiary of a steel or energy group), usually the HSE manager or yard supervisor, as part of preventive monitoring or a periodic audit.
Is flying over a port terminal subject to a specific authorisation? Beyond the usual framework (open category, prior declaration in a populated area), some ports set their own internal air traffic rules ; these are arranged directly with the harbour master's office or the operator when booking the mission.
Put it into practice
- Drone aerial thermal imaging: rates and cities covered from €500
- Aerial thermal imaging in Épinal Grand Est
- Aerial thermal imaging in Marseille Provence-Alpes-Côte d'Azur
- Aerial thermal imaging in Bordeaux Nouvelle-Aquitaine