**2. Maintenance strategies and framework**

The systematic, optimally sequenced activities and framework, through which mining companies can sustainably manage their equipment, its performance, risks and operating expenses over their entire life cycle, for the purpose of achieving its organizational objectives and plan, can be defined as an enterprise asset management. Mining equipment maintenance requires series of checks by the equipment operator, for better diligence apart from unscheduled fixes. The frequency is dependent on the combination of equipment performance and the running hours in a specified time interval.

Maintenance costs can be upto 30% of direct costs [4] and more in terms of operations disruptions. To control maintenance costs, mining organization have centred their efforts on areas such as optimizing scheduled maintenance operations, deferring nonessential maintenance, reducing maintenance manpower, controlling inventories of spare parts even more adequately, and using contract maintenance support [5]. Below all the maintenance types, which are performed by the maintenance team at varied frequency depending on the nature of inputs from various sources are described

## **2.1 Regular maintenance—Type I**

The first daily checks and safety practices are mandated by the OEM and occur the start of every shift or during operator changes. These proactive checks involve the inspection of all major system parameters such as engine temperature, tyre pressures, oil levels and control surfaces and are performed at the mine site itself. These checks can be part of the total productive maintenance (TPM) strategy and incorporates activities and actions performed by equipment operators with the intention of to ensure failure-free operations, fewer breakdowns and efficiency [6].

## **2.2 Preventive maintenance—Type II**

Routine planned maintenance is about avoiding, reducing or eliminating the consequences of failures. The frequency of performance-based maintenance is done *An Innovative Maintenance Scheduling Framework for Preventive, Predictive Maintenance… DOI: http://dx.doi.org/10.5772/intechopen.103094*

primarily on performance (running hours, KM run) of the equipment, time based (weekly, monthly, quarterly, yearly, and multiple of years) or as recommended by OEM and updated time to time.

The determination of inspection intervals is based on the reliability level to prevent potential catastrophic failures that augments extensive maintenance and increased downtime costs. The insights are considered to develop a preventive maintenance plan that is based on the deterioration of equipment key components and renewed life after repair [7]. The mechanical parts deterioration factors depend on multiple factors which are wear and tear, corrosion, operational fatigue and weather, and operator skills. This deterioration is a continuous process which is time and usage dependent [8].

## **2.3 Breakdown or corrective maintenance—Type III**

The unscheduled breakdown has a major impact in both – production and expedited maintenance costs. Furthermore, the ability to fix it right first time is fundamental to ensure equipment is back to operation quickly. The core objective for repairing the equipment is in less time, with higher accuracy and support maintenance technicians to diagnose the failure properly is key for improved utilization. The breakdown and corrective maintenance require timely availability of spares and management of spares just in time is one of the main challenges of delay in maintaining of the equipment.

Condition based maintenance (CBM) provides the insights of the equipment component, either real time or at a specific frequency to analyse the condition for effective decision making for dynamic corrective maintenance schedule for restoration. CBM insights can be utilized either for preventive or corrective maintenance depending on the organizational maintenance strategy [9].

## **2.4 Overhaul and shutdown maintenance—Type IV**

This type of maintenance is mostly capital in nature and performed at relatively large intervals. It may be done for several reasons due to severe break- down, accident or to overhaul the entire equipment to enhance the useful life of the equipment. This overhaul or shutdown maintenance is managed as a project with procurement of spare parts and maintenance activities are scheduled and synchronized as per the timeline agreed upon. Overhaul is complete check and review of the mining equipment and depends on the performance of the equipment or between the mid to end of useful life to enhance the useful life of the equipment. This type of maintenance is performed mostly on the large equipment for example, dragline and shovels. This maintenance can run up-to multiple months and are managed as a project with a sequence of activities and schedules, to minimize equipment downtime.

## **2.5 Predictive maintenance—Type V**

This type of maintenance is performed based on accurate prediction when an equipment or any of its components are going to fail. If the prediction attribute is derived the maintenance can be executed just before such failure is predicted to occur.

There are systems like vehicle health monitoring system (VHMS) which provide, frequency-based sample data about the equipment performance for example, running hours, speed, rpm, load, engine temperature, payload so on and so forth. Similarly, weather related data is collected through weather application programming interface (API), which helps to understand the impact of ambient temperature, precipitation, humidity etc. on the equipment performance. The main idea
