In For The Long Haul

Difficult business conditions for the mining sector mean many operators are looking to extend purchasing cycles and run mining trucks for longer. 

Mine operations entail a constant battle to keep the cost of production as low as possible, and with weak commodity prices affecting many mines in southern Africa, keeping costs down is more important than ever.

Haul trucks are a major component of a mine’s operations, and hence an opportunity to streamline production. In the best-case scenario, a site running its haulers efficiently may be able to achieve the same production with fewer vehicles, saving on capital costs as well as fuel, wear and maintenance. On the other side of the equation, inefficiencies such as high idling time or high wear and tear will add to production costs.

Tyres are among the highest costs for a hauler after fuel, and poorly maintained haul roads can dramatically increase wear on tyres, notes Darren Holder, mining sales manager at Hitachi Construction Machinery Africa. Nevertheless, maintaining haul roads can be near to impossible in certain climates.

“If it rains a lot and there are very wet seasons, and with the tyres compacting in different regions with a huge tonnage, it causes a lot of ruts in the roads and it’s very, very hard to maintain that. A lot of the time it’s not neglected by the mine, it’s just too difficult to maintain,” he says.

The quest for lower costs and better efficiency helps explain the shift that Holder sees among “most of the industry” to electric drivelines on larger trucks - 180 tonnes and above. An electric driveline truck produces significant savings on fuel as well as improved productivity and lower wear costs, he says.

Driving under the trolley achieves faster trips out of a mine’s pit.

Hitachi’s range of AC-3 trucks - the EH3500AC-3, EH4000AC-3 and EH5000AC-3 - are the first to be fully developed by Hitachi in-house, says Holder, with the whole drive system designed by Hitachi, including the adoption of technology used in bullet trains.

Optimally, the Hitachi trolley system can increase the speed of the trucks running up a mine’s ramps out of pit. At the Kansanshi copper and gold mine near Solwezi in Zambia - a major buyer of Hitachi haul trucks - the AC trucks under the trolley can drive up the ramp at double speed.

BELAZ is another manufacturer offering electric driveline haulers, from its 90-tonne BELAZ 7558 hauler with an AC/AC electric drive transmission, up to its 450-tonne payload 75710, the world’s largest, highest payload capacity haul truck. The first 7558 truck produced was delivered to South Africa, says Dmitry Venchyk, CEO at BELAZ Africa, the local distributor for South Africa since 2009. He explains that the brand has been present since the mid-’90s, and today there are 50 BELAZ trucks in South Africa, with the most popular size being the 220-240-tonne payload capacity class.

Venchyk sees a number of key advantages of the electric driveline type, compared to the mechanical, including increased efficiency for lower fuel consumption, higher ramp speed to reduce cycle time, and better dynamic retarding capability that allows a AC truck to drive downhill at higher speed.

“[The] asynchronous traction motors and more advanced control of electrodynamic deceleration allows to hold the truck when driving at higher speeds and provides a smooth deceleration up to a complete stop, with the ability to hold the dump truck without the use of mechanical brakes,” he says.

Haul trucks can be sold with a number of different service options.

Separate torque control also increases tyre life, while a truck with electric driveline consumes much less hydraulic and transmission oil than a mechanically driven one, and has lower maintenance costs, Venchyk adds.

Holder believes that the future will be hybrid trucks and then fully electric trucks, using technologies such as regenerative braking on downhill loading or going into the pit, with a trolley system to recharge batteries while coming out of the pit. “There’s a lot of talk in the industry that that’s the way the future is headed.”

Approach angle

Venchyk notes several advantages of the BELAZ haulers, including a capital cost 10-20% lower than that of competitors, fuel consumption up to 15% lower than for competitors’ trucks of similar size, and a design that is easily understood by local technicians. Another advantage is short lead time. “We can [offer] the most competitive lead time in the industry,” he says. “We ensure availability of ready-to-work machines exactly when needed for the customer.”

At the heart of the BELAZ trucks, customers have an option of a “reliable and proven engine” from Cummins or MTU, he adds.

“Industry analysts are projecting considerable operational productivity improvements in the medium to long term, through implementation of autonomous and integrated mine optimisation technologies.”

Machine reliability and maintenance costs can be a major contributor to a mine’s overall performance and profitability.

Using engines from suppliers is one route taken by a number of OEMs, while others are known for producing their own engines for their haul truck range.

Komatsu’s top selling rigid frame hauler globally is the 930E, which comes in several variants. The 930E-4 is powered by the Komatsu SSDA16V160 engine, which is also used in other trucks including the 830E-AC.

Caterpillar says its 797F rigid frame hauler is the best-selling truck in its 363-tonne size class, as well as delivering the lowest cost per tonne. It is powered by the Cat C175-20 engine.

Tough conditions

Most agree that market conditions are currently difficult, with prices down for a number of key commodities, including coal. Holder points out that many mines, especially those that are struggling, are trying to extend the lives of their haulers for as long as possible. Some operators are even considering selling or mothballing mines, especially with negative forecasts for coal prices. “They’re definitely trying to delay purchases for as long as possible,” he says.

BELAZ promises industry beating lead times.

Venchyk describes the business environment in South Africa as “not easy”, with rising labour costs affecting the price of final products. “Then mining operators need to save funds on something else in order to stay competitive, for example on purchasing of new equipment,” he explains.

Artic haulers

When it comes to articulated dump trucks, Terex Trucks’ two articulated haulers, the 28-tonne TA300 and the 38-tonne TA400, are popular among mining companies throughout South Africa, mainly used for coal mining. Despite the decline in investment in the sector, coal mining remains a significant economic force, contributing 344bn South African rand ($24.1bn) to the country’s gross domestic product in 2018.

The TA300 was upgraded in late 2018 and is now manufactured with the latest EP320 transmission. The updated machine delivers a 5% improvement in fuel efficiency, a 5km/h increase in speed to 55km/h, an extended maintenance period, and enhanced performance compared with the previous model.

Despite difficulties in the coal sector in South Africa, it remains an economic force. Articulated haulers are widely in coal mines.  

Meanwhile, the TA400 boasts a heaped capacity of 23.0m3 and is powered by a high-performance, fuel-efficient engine that develops a gross power of 331kW and a maximum torque of 2,255Nm.

Outside of mining, construction and infrastructure development are also expected to drive demand for articulated haulers. The total construction project pipeline in South Africa, including all mega projects, stands at 2.6 trillion South African rand, and the country’s construction industry was expected to emerge from recession and grow by 2.4% in 2019.

“With so many new projects in the pipeline, we have identified South Africa as a key market for Terex Trucks,” said Roger Teece, EMEA Regional Sales Manager at Terex Trucks. “We want to reach out to new customers and introduce them to our robust, reliable articulated haulers, as well as reinforce our commitment to existing customers in the region.”