The process of material transportation is a crucial aspect of a mining project and tipper trucks have been known to streamline the same since years. Improved efficiency and productivity of trucks & tippers improves the overall productivity and efficiency of any mine. While purchasing mining trucks, miners look for better operating efficiency and increased productivity in terms of payloads, capacity, mileage, better utilization, minimum downtime and enhanced driving comfort. High capacity trucks decreases the transportation cost per ton, ergonomically designed driver cabin improves driver comfort and reduces fatigue, and use of technology improves vehicle uptime and helps in better fleet utilization.
Mining activity demands off-site and far-away operations which require heavy commercial vehicles such as tipper trucks to handle the material transportation needs. Tipper trucks, also known as dump trucks, are used to transport lose materials like loose rocks, gravel, sand, etc. Mining sites have certain areas, which are inaccessible unless loose materials are loaded off. Bigger off-highway dump trucks, better known as Haul trucks, are used in sites like open-pit mining where they are responsible for depositing the overburden material or mineral ore at a certain site or area. While heavy duty on-highway tipper trucks are used to transport the material from mine to processing centers or next loading station.
Different size and types of dump trucks are available in the market to suit the mining project requirements. Rigid body, articulated, rear discharge, bottom discharge or belly discharge are some of the types to name a few. The choice for size and type of dump trucks at any mine will depend on lot of variables, such as the type of mine, size of mine, minerals being mined, capital invested or investable, or excavation machinery available. However, in the shortlisted ones, the key customer requirements are uptime, durability and lowest cost of operation. The tippers need to operate over long duty cycles, providing maximum productivity in tough operating conditions.
Bigger is Better
The mining transportation industry was earlier using the conventional inefficient 4x2, low capacity tippers, primarily designed for construction work or depended on large, gas guzzling dumpers. They were difficult to operate efficiently in most of the Indian mines with deep coal pits, narrow roads and faraway dump sites.
Demand in multi-axle has shifted from the 4×2 configuration to the 6×4 & 8x4 categories and, in some cases, to 10×4 configurations tipper trucks. The more number of axles a tipper has, the better the weight carrying capacity. Simply put, a tipper with more axles can carry more weight easily. Nowadays, buyers prefer mining tippers with 30-40 tonne payload capacity and haul trucks of 50 tonne, 60 tonne, 100 tonne capacity and even more upto the highest capacity available worldwide. BelAZ 75710, manufactured in Belarus, is the biggest haul truck in the world, capable of hauling a whooping 450t of materials in one load. Caterpillar, Liebherr and Terex/Bucyrus with 360t and Komatsu with 325t are among the top five trucks in terms of hauling capacity.
Use of Technology
Number of digital features can be integrated into the vehicles that play an important role in the smooth functioning of the vehicles and its maintenance. It helps in improving the cost efficiency, better fleet utilisation through trip assignments and tracking of the vehicle, monitoring the driver behaviours, providing insights on driving habits etc. which with proper training and feedback can help in preventing accidents.
The total cost of ownership (TCO) for a customer can be significantly reduced through the connected technologies such as automatic transmission, telematics, advance safety system, driver assist etc. enabling better upkeep of vehicles, lower downtime and faster responses to breakdowns in addition to improving the operating efficiency of the fleet owners. Telematics is not just about monitoring but also bringing transparency in business processes and efficiency. Remote diagnosis and assistance help owners in getting improved uptime/turnaround time. Use of technology drive efficiencies and enhance the profitability for the customers.
Onsite safety is gaining importance in the mining industry. Inbuilt basic and advanced safety features with other additional accessories help prevent truck overturning and accidents. Tipping Inclinometers, Body Up alarms and warning lights, Speed limiters, Payload Meter or load indication light, Additional reversing cameras and working lamps, In cab warnings and tipping reminder stickers, High visibility LED running and service lights, Anti roll-back feature (active in forward and reverse), Automatic traction control & differential (diff) locks, Hill start aid, Ejector bodies and Remote GPS machine monitoring are some of the tipper truck safety features and accessories that help in safe and efficient in mine and out bound mining transportation.
AC Electric Drive Systems
When fuel efficiency, hauling productivity and operating costs are high on the priority list, mine operators, for example, are often drawn to trucks with electrically-driven wheels powered by diesel generators, instead of mechanical power train mechanisms with gearboxes and drive shafts.
AC drive technology is a very efficient means of powering large haulers. AC drives allow smoother acceleration at slow speeds, better gradeability, and higher top speed. AC drives also minimize routine maintenance with their brushless design.
The AC power is temporarily converted to DC by a diode rectifier. This voltage-stabilized and –conditioned power is stored in a common DC link. The electrical power passes through the capacitors to two inverters, which produce the AC power for the traction motors. The output frequency and voltage of the inverters is controlled to provide precise motor torque and speed.
One of the most significant advantages of a diesel electric drive system is the powerful, dynamic retard capability which minimizes brake wear. The same electricity that is used to propel the hauler can be switched by “braking choppers” into resistance that can be used to slow the traction motors.