Improperly maintained or abandoned fuel and chemical storage tanks can pose serious safety and environmental risks, including potential explosions and contamination of soil and groundwater.
Most mining sites use self-bunded fuel tanks, which, with regular maintenance, can prevent costly fuel leaks and avoid substantial clean-up expenses mandated by environmental legislation.
Despite the transition to sustainable energy sources, diesel fuel remains essential for heavy machinery and generators on remote mine sites.
Installing fuel storage tanks, whether small mobile tanks or large bulk tanks, can help mining operations reduce fuel costs and minimise delivery times.
Given the volatility of fuel prices, having a storage solution allows miners to capitalise on lower prices and enhance fuel management. Many suppliers also offer discounts for bulk purchases.
Modular and transportable fuel tanks are particularly beneficial in the mining industry, where fuel requirements fluctuate based on operational demands.
Beyond self-bunded tanks, fuel storage options include aboveground and below ground solutions. While above ground tanks typically offer greater capacity, below ground options are often chosen for space constraints or aesthetic considerations.
When companies cannot repurpose existing infrastructure, demolition and remediation become essential to mitigate environmental impacts and prepare sites for future use.
If the removal of tanks is impractical due to proximity to surrounding structures or underground infrastructure, decommissioning in situ may be necessary. This involves rendering the tanks safe while leaving them in their current positions.
Soil beneath decommissioned tanks must be sampled to assess the potential release of toxic contaminants. Testing for vapours and chemicals in the ground is also required, as the presence of gases must be evaluated.
In Queensland, work health and safety legislation defines an underground tank that has not been used for two years as abandoned.
WorkSafe QLD warns that working around these tanks or their associated pipework poses significant dangers due to residual flammable gases, liquids, and vapours.
The health and safety regulator said: “Introducing an ignition source (e.g. activities such as grinding, hot cutting or welding), excavating around or disturbing abandoned underground tanks may cause an explosion or other dangerous occurrence.”
Abandoned tanks may contain tar-like deposits and sludge that flushing with water may not remove, and vapour testing may not detect.
If these deposits are exposed to air and sunlight or subjected to heat, such as from grinders or cutting equipment, they can release vapours, increasing the explosion risk.
This danger was underscored in New South Wales less than two years ago, when an explosion during the removal of an underground storage tank containing unleaded petrol injured three workers and severely damaged nearby buildings.
WorkSafe NSW reported that two workers were near an excavated pit, and a third worker operated an excavator attempting to remove the tank without appropriate lifting equipment when the explosion occurred.
The investigation revealed that the explosion was triggered by introducing an ignition source into a hazardous area.
Contributing factors included residual petrol in the tank, failure to monitor for flammable vapours, improper methods for freeing the tank of chemicals, and lack of experience among the subcontractors involved.
Hence, proper decommissioning and management of abandoned fuel tanks are crucial to safeguarding both personnel and the environment.
