## 2 Literature Review
### OEE Development in Transportation Context  
An indicator of road transportation effectiveness and productivity was introduced called overall vehicle effectiveness (OVE) [12]. OVE measures the overall effectiveness index related to the transportation process (vehicle effectiveness) using OEE principles. There are five inherent transport losses or wastes identified in OVE: driver breaks, excess load time, fill loss, speed loss, and quality delay [12]. Losses that affect the availability, performance, and quality rate in transportation compared to losses in traditional OEE are described in Table 1. The OVE calculation method measures the availability, performance, and quality of the transportation process based on the above five losses. According to the OVE calculation methodology, activities of the transportation process are divided into those with added value and those without added value for the end customer. Original OVE did not consider energy efficiency when making the transportation route selection, where OVE calculation methodologies assign higher OVE values to less energy-efficient routes when delivery or collection takes place to/from a significant number of destinations (multiple points). This issue was identified for multiple drop-offs or collections. To solve it, a new component was added to the OVE that measures the route effectiveness. Thus, OVE assumed a new shape and name to become modified overall vehicle effectiveness (MOVE) [13]. Another specific metric to measure the overall efficiency of the transport process has been introduced. To maximize the availability utilization of company fleet vehicles, it was recommended to calculate the OVE metric based on full calendar time [14]. The lower the availability utilization, the higher the cost of the transportation process. Thus, the calculation of the OVE metric based on total calendar hours consequently led to creating transportation overall vehicle effectiveness (TOVE). The TOVE methodology considers several new losses related to vehicle availability, time, preventive and unscheduled maintenance, breakdowns, excessive delays due to customers, and quality of service [26]. The efficiency of transport processes in the TOVE metric is obtained by multiplying the administrative availability, operational availability, performance, and quality rates [26]. A new metric to measure vehicle fleet energy efficiency was introduced that represents another transport process effectiveness metric [15]. This metric takes energy efficiency into account. Energy efficiency is the level of energy consumed in transportation operations. The energy efficiency of a transport process is the ratio of transport volume to vehicle fleet energy efficiency consumption, expressed in ton-kilometers per kilowatt hours. The vehicle fleet effectiveness metric is called OVE Human and combines several components, including the availability utilization rates of vehicle and driver, the performance of vehicle and driver, and the transport process quality including fleet energy efficiency and quality of supply services [15]. Based on the literature review for TOVE, we found eight potential metrics as described in Table 2. We used this specific literature since it discussed the metrics related to overall vehicle effectiveness in the road transportation context. The OEE application in the mining industry differs from that in the manufacturing industry because the physical environment in which mining equipment operates is less than ideal [8]. Some challenges in the mining industry have been described: a physically challenging environment, an inherently variable environment, geographically spread output teams, inherently variable raw materials, and remote locations [16]. The dynamic nature of mining operations introduces a high degree of uncertainty into various unit