# Safety Challenges in Battery Swapping Operations of Electric Underground Mining Trucks
## 3 Identification of Hazards and Risk Assessment During Battery Swapping
Ambient heat/Heat stress/Radiant heat--heat emitted from the equipment; \(\bigcirc\) The battery charging process is closely related to the heat emission. Considering the size of the charging stations, this hazard may become relevant both regarding legally regulated temperatures for the human working environment and the equipment's operational temperature ranges, which is of high relevance for the lithium-ion batteries. The estimated probability rank of this hazard is 4, and the consequence rank is 2; 17. Ventilation--the requirement of providing a sufficient amount of fresh air and to create acceptable temperature at the work site; \(\bigcirc\) This is closely related to the previous hazard. Supply of fresh air is not seen as a major hazard, since there is no air consumption during the battery charging process. However, ventilation may be influenced by the requirement to secure specific room temperatures inside the charging station due to numerous heat emission sources. In some cases, air conditioning (cooling) may be required to create acceptable working conditions. The estimated probability rank of this hazard is 3, and the consequence rank is 1; 18. Contact--contact with hot or cold surface; \(\bigcirc\) In general, no sizable items with high or low temperatures will be present inside the charging station. However, specific smaller components such as connecting sock pins, components of the charger or components of air-cooling equipment (if used) may be at temperatures which could cause an injury. The estimated probability rank of this hazard is 2, and the consequence rank is 1; 19. Pushing and pulling--the risk of injury during manual work; \(\bigcirc\) This risk is related to handling the battery as a load (fixing the ropes/chains/ slings to the battery) and handling the power supply cable for connecting and disconnecting. Both activities require some level of manual work, during which injury can occur. The estimated probability rank of this hazard is 2, and the consequence rank is 1; 20. Short circuit--the hazard from the unintended current path; \(\bigcirc\) This is usually related to the abnormal electrical connection between two or more conductors, where batteries with low internal resistance are capable of generating dangerously high currents in case of short circuits. Short circuits in charging stations can occur due to equipment malfunctions and environmental factors (humidity, dust, debris, etc.). It can result in major to catastrophic consequences to humans and equipment. The estimated probability rank of this hazard is 3, and the consequence rank is 4; 21. Arcing (arc flash)--the electrical hazard of current flow through the air; \(\bigcirc\) Current flow through the air can occur between conductors or from one conductor to a grounded object due to malfunctioning insulation or an accidental short circuit. The consequences of this hazard can be very serious for workers and can also damage the equipment. The estimated probability rank of this hazard is 3, and the consequence rank is 5; Risks associated with the above hazards are assessed with a well-known 5 \(\times\) 5 matrix [25]. This matrix is visually represented by a table with five categories of probability (the likelihood of a specific risk occurring) and five categories of consequences (the impact of the risk once it occurs). Categories of probability with associated values (in brackets) are:  
* Rare (1)--highly low probability of hazard, negligible;
* Unlikely (2)--low probability of hazard to occur, not negligible;
* Possible (3)--moderate probability of hazard to occur. Such a hazard is not uncommon, but also is not frequent;
* Likely (4)--a high probability of hazard to occur, occasionally, or repeatedly;
* Almost certain (5)--the highest level of hazard to occur, frequently. It is expected that battery swapping (replacing the discharged battery with a charged one) will take place once to twice per shift, meaning that identified hazards will occur frequently.