# Safety Challenges in Battery Swapping Operations of Electric Underground Mining Trucks
## 3 Identification of Hazards and Risk Assessment During Battery Swapping  
Risk assessment is a fundamental process in OH&S that systematically identifies hazards, evaluates the risks they pose, and, when necessary, provides measures for risk reduction. This process involves risk analysis of identified hazards associated with various tasks, assessing their probability and consequences within an established acceptance criteria framework. A flowchart of this process is shown in Figure 4.  
The risk assessment process described in this section will follow the sequence shown in the figure above. The first step is hazard identification, which is performed according to standard safety practices and available information [21; 22; 23; 24], as well as during several rounds of sessions with safety experts and OEM personnel. In the next step, the probability of a hazard occurring is assessed by the frequency of personnel and equipment exposure to specific hazards. Similarly, consequences are evaluated according to hazard exposure scenarios. Probabilities and consequences are also the topic of discussion rounds with safety experts and OEM representatives. Finally, the risk level is assessed with a 5 by 5 matrix according to probability and consequences. The presented approach has inherent subjectivity, since this is a new technology in underground mining conditions and due to the lack of safety-related metrics. So far, it is understood that there are two systems for battery swapping available from the major manufacturers. Both systems are located in single-entry chambers. One utilises an overhead crane for manipulating the batteries (Company 1), while the other features a vehicle-based system for the same purpose (Company 2). Both companies envisaged one  
Figure 4: Scheme of risk assessment procedure. worker for completing the task of battery swap--a machine operator, but it is unclear if there are additional workers in the charging station. Bearing in mind the described procedures for battery swapping, a total of 21 hazards are identified, occurring in 25 instances (some hazards are occurring in separate circumstances). These are listed below. 1. Crushing/Impact--the risk of injury by crushing the operator by fixed and moving object (battery). 2. This hazard occurs during the battery handling--load lifted with the overhead crane. The estimated probability rank of this hazard is 2, and the consequence rank is 5;
3. The same hazard occurs during machine movement in situations when other people are present in the charging station. The estimated probability rank of this hazard is 3, and the consequence rank is 5;
4. Moving equipment--risk of equipment damage by moving objects;
5. Hazard similar to the previous one, but in regard to the equipment and assets present at the site. The estimated probability rank of this hazard is 2, and the consequence rank is 3;
6. Pinch points--the risk of pinching the part of the human body between two objects. 7. Pinching hazard is present during connecting and disconnecting the power supply cables to the battery. The estimated probability rank of this hazard is 2, and the consequence rank is 2;
8. Pinching can occur during the suspended load handling and fitting the slings and ropes to the load (battery). The estimated probability rank of this hazard is 2, and the consequence rank is 3;
9. Static stability--risk by disrupting the static balance (equilibrium) of forces by adding or removing the weight;
10. Adding and removing the weight (battery) impacts the static stability of a battery-powered machine by moving the machine's centre of gravity. The estimated probability rank of this hazard is 2, and the consequence rank is 5;
11. Dynamic stability--the impact of dynamic forces and velocity on the system;
12. Manipulating the battery with an overhead crane generates dynamic forces in lifting ropes/chains (swinging) and the load-bearing structure. The estimated probability rank of this hazard is 3, and the consequence rank is 3;
13. Mechanical strength--the strength of all load-bearing components;
14.