With hybrid truck fleet models becoming more common at African mines, designing articulated dump trucks (ADTs) to enable them to operate all year round and in different climates offers mixed truck fleet operators versatility and efficiency, according to heavy equipment manufacturer Bell Equipment ADT marketing manager Brad Castle.

One such design is Bell Equipment’s 4×4 ADT, which offers a lighter weight, less drivetrain complexity and greater efficiencies on fuel, and a decreased need to replace tyres and suspension components over the more traditional 6×6 ADT.

First termed a “quarry truck” when it was launched in 2012 and 2014, the Bell Equipment 4×4 ADT range – including the B30E, B45E and B60E – aims to provide users with a solution to help save operational costs through Bell Equipment’s lower cost per tonne design.

“When it comes to fuel efficiency, it’s not as straightforward as [using only] a fuel efficient engine. Although [a fuel efficient engine] is one of the factors, there are a whole lot of other variables that you need to design well to contribute to that overall fuel efficiency,” explains Castle.

As a result of the incorporation of other systems to lower operating costs, Bell Equipment’s 4X4 ADTs use a Mercedes-Benz engine and Allison transmission, providing a light and efficient drivetrain combination.

The Allison transmission is equipped with the Allison Fuel Sense Calibration system, which automatically changes gears according to a haul road’s profile.

As an example, Castle explains to Mining Weekly that when the ADT is going downhill, operators benefit from the transmission’s design that favours higher gears, so as to burn less fuel; while when ascending the 4×4 ADT will hold lower gears for longer periods to maintain torque and momentum.

In addition, one of the biggest contributing factors to fuel efficiency is the ADT’s cooling system and its design for efficiency.

The type of cooling system incorporated into Bell Equipment’s trucks uses a direct engine-driven fan, which serves to simplify the overall cooling system.

Other variants of mining trucks use hydraulically-powered fans, which rely on hydraulic oil, which in turn needs to be cooled efficiently.

As a result, hydraulic-intensive trucks will have to use more engine power and more fuel to power auxiliary systems.

ADT Applicability

Throughout the early stages of a mine’s development, Castle says ADTs can serve as supplementary machines in mine establishment, as haul roads are often not well established, making it difficult for rigid-frame dump trucks (RDTs) to operate efficiently.

However, he adds that an ADT is a suitable machine for any mine, in any phase of development or operation, as it is a lot more versatile and can be used in other parts of a mine where more agile trucks are required.

In many mass mining applications, a traditional 6×6 ADT is unnecessary for a mine’s ground conditions, as such trucks use an extra axle that adds to drag and additional drivetrain components.

“Although a 4X4 ADT does not replace a 6×6 ADT, it does fill a gap where a 6×6 ADT is not needed,” says Castle.

In addition to conditions, ADTs also offer full-year serviceability as some mines struggle to operate RDTs during rainy seasons, he notes.

Meanwhile, to enhance fleet management, promote interoperability and increase the safety, efficiency and productivity of its machines, Bell Equipment has fully incorporated the Internet of Things into the design of its ADTs.

In addition to this, the company has also chosen to be technology agnostic, meaning that the computer system used in Bell Equipment’s ADTs integrates easily with various third-party technologies, aimed at making operations safer and more productive, such as in the use of proximity detection systems and collision avoidance systems.

Bell Equipment’s ADTs are also designed with a technologically advanced platform with access to the manufacturer’s Fleetm@tic telematics system, providing fleet owners and operation’s managers a complete picture of their machine health and productivity from one user-friendly interface.

“Customers have a secure login and password, which enables them to monitor their machines from anywhere, at any time. They can generate reports to be delivered daily, weekly or monthly,” explains Castle.

Fleetm@tic is a “highly effective tool to identify bottlenecks, balance workloads and schedule proactive maintenance to reduce unplanned downtime”, he adds.

Fleetm@tic connects to the Bell ADT’s payload monitoring system, enabling operators to monitor daily productivity metrics, including fuel levels, fuel use and how far the truck has driven.

In terms of safety, Fleetm@tic provides real-time tracking of a machine’s location, speed and operating status.

Additionally, for asset management, Fleetm@tic’s geofencing capability enables operators to set safe zones, speed limits and prohibit tipping in hazardous or restricted areas.

“We have a lot of automated features in the truck that will reduce machine abuse. While these systems protect the machine, they also make operation easier and more user-friendly, which will hopefully improve operator performance,” concludes Castle.