"It's like driving a house," says Francis Bartley, the man who designed Liebherr's T282B dump truck. He's not exaggerating. The T282B is the largest capacity mining dump truck in the world. It boasts a 3,650-horsepower engine that guzzles 50 gallons of diesel per hour, 13ft tyres and a body capable of carrying approximately 400t.

It's fair to say that, in terms of machinery, the mining industry is thinking big. Caterpillar's 797B is just as capable as the T282B of shifting around 400t, whilst Komatsu's 920E-29 can take well-over 300t. Order levels for these monster trucks are higher than they have been for 25 years.

The question is: in an age where mobile phones and computers are getting smaller by the day, why is mining machinery getting bigger?

How are manufacturers responding to miners' needs? And is the 500t payload truck just around the corner?

Economic pressure

"We are continuously looking into the improvement of our equipment to make it more efficient for the customer," says Liebherr Mining's product marketing manager Dion Domaschenz. "This may be in the form of ground-breaking design concepts, integrating the latest in technology or by way of improved customer support in terms of spare parts supply or technical assistance in the maintenance aspects."

The driving force behind this constant straining for improvement in the performance of the machinery is economic. Earlier this year BHP Billiton, the world's biggest mining company, posted a record-busting before one-off items net profit of $13.68bn. The company's peers CVRD, Xstrata and Anglo American also revealed hefty profits.

"Big mining companies will be keeping the pressure on manufacturers to constantly eke more efficiency out of their machines."

Whilst many look to exploit the boom and expand or, in the case of base metal mining companies, try to complement the fall-off in supply from ageing operations, it is clear there is both the need for better and more efficient machinery and the money available to invest in it.

For the mining industry better often means bigger. Where once a 240t-capacity dump truck was sufficient, a capacity of 400t is now expected. Liebherr's production of the monster trucks has increased 10–15% every year for the last five years to cope with the burgeoning demand.

However, whilst reporting record-breaking profits, BHP also noted that costs such as labour, raw materials, fuel and energy had risen in the last year by 3.6%.

With an eye on their profit margins and the continued threat that the price of commodities like gold, copper and iron may fall, it's a fair bet that the big mining companies will be keeping the pressure on manufacturers to constantly eke more efficiency out of their machines.

"It is a mixture of many things," says Domaschenz. "You need to look at transport and logistics limitations, potential customer base, costs, availability of components and risk. Costs are unlikely to be linear as the size of the equipment and components increase."

Environmental effects

The other great pressure fueling the drive for greater efficiency and productivity from mining machinery is the environment. Due to ecological concerns associated with mining such as pollutants from drilling and blasting as well as leakage of fuel, oil, and other lubricants into ground water, it is becoming increasingly difficult for companies to open up new mines, increase the capacity of existing ones or even extend their mining licences.

"It is becoming increasingly difficult for companies to open up new mines, increase the capacity of existing ones or even extend their mining licences."

Subsequently, companies are forced into continually mining the same areas, driving demand for greater capacity and larger machinery to maintain the profitability and productivity of the mines.

Technological responses

Manufacturers have responded to the clamour for greater efficiency by producing better equipment. Improved motor design, process sensor controls, online analysis, advanced communication technologies and instrumentation robotics are just some of the areas in which energy and production efficiencies have been increased.

Changes to the machine design process, including automating and integrating the manufacturing and assembling process, have increased the speed with which manufacturers can respond to the industry's demands.

Monster trucks

To be financially successful, a mine needs to move a high volume of material at as low a cost as possible. The more it moves in one go, without affecting its costs per ton, the higher its profit margins will be. That's where the monster trucks come in.

In the early 1950s hauler trucks had an average capacity of 27–35t each. By the 1960s capacity had increased to 85–200t and by the mid-1980s 240t-capacity trucks were standard. However, by the time the new millennium came around, Caterpillar and Liebherr found a way of nearly doubling that capacity.

"Standing over 24ft tall, the 797B is powered by a 3,500hp engine, has a designed operating weight of 1,230,000lb and a capacity of 360t."

The 797B was first seen at the Caterpillar proving ground in Tucson, Arizona, in 1998. Three years later, it became commercially available and mines around the world got their first taste of big. Standing over 24ft tall, the 797B is powered by a 3,500hp engine, has a designed operating weight of 1,230,000lb and a capacity of 360t.

The Caterpillar 797B and the Liebherr T282B may be powered differently – Caterpillar has developed a mechanical-drive engine whilst Liebherr's truck uses diesel engines to power electric generators – but they are both music to the ears of mining companies as they allow them to shift more material more quickly and turn a bigger profit.

In addition, Liebherr's T282B is lighter and more fuel efficient than mechanical drive trucks, allowing users to cut cost per ton figures by using less fuel.

Continuous miners

Joy's continuous miner is the largest underground mining machine in the world, according to the makers of TV show 'World's Biggest Machines'. Since its original release in 1948, the continuous miner has constantly evolved to meet the demands of the mining industry.

One of the latest versions, the 12HM31-B MkII high-voltage 3.3kV machine, was developed by Joy South Africa in response to the demand from local mining companies for a higher productivity despite the hard-cutting conditions of the region.

The machine features the AC variable-frequency traction drive system Optidrive and the online JNAII surface communications system. It also includes the WetHead system, which reduces respirable dust levels, improves visibility, has an improved bit life and consumes less water than standard dust sprays.

The biggest Joy continuous miner, the 12HM36, is 3.54m-high, 14.1m-long and weighs more than 120t. It is used for potash, salt and gypsum mining, whereas the 12HM31 is used for coal mining.

"The more material that can be excavated and transported in one go, the higher the profit margins will be."

Excavators and loaders

Increased productivity gained by economies of scale is what is driving this evolution. In August Russian giant Mechel splashed out £3m on a pair of new backhoe excavators. The Liebherr and Komatsu machines would allow the company to increase annual ore excavation by 30%.

It is little wonder, then, that manufacturers are falling over themselves to go large.

At Bauma 2007 Liebherr premiered a new excavator, the R9250, which has 15% more bucket capacity and 42% greater swing torque than its predecessor, giving it much greater overall productivity. In April Caterpillar unveiled the 993K; a 25t-capacity, 1,050hp wheel loader in a size class of its own. Komatsu this year launched a pair of wheel loaders which it says are 'more powerful, more stable and more environmentally friendly than their predecessors'.

Future plans

Bigger often means better in the mining industry because the more material that can be excavated and transported in one go, the higher the profit margins will be. But size isn't everything. Witness Caterpillar's new motorgraders, with joysticks replacing up to 15 levers, for an example of how cuteness can also lead to higher productivity.

"When it comes to large equipment there are challenges which exist in terms of component suppliers and transport and logistics."

However, a trawl through the product catalogues of vehicle manufacturers shows that many of the new and forthcoming trucks, loaders and excavators will be bigger, more powerful and more efficient than their predecessors. So should we be expecting a 500t payload truck in the near future? Not in the next few years, according to Liebherr's Dion Domaschenz. In fact, he says, bigger won't necessarily mean better as the industry progresses.

"There is pressure of course to push the limits of technology but when it comes to large equipment there are challenges which exist in terms of component suppliers and transport and logistics," says Domaschenz.

"There are many mines around the world which are currently not using the largest equipment currently available today and to go a step bigger than what is currently out there now effectively means that your potential customer base for the new product gets smaller as not everyone can use the equipment.

"With large trucks, you need large tyres and large engines, so there is a huge development cost with a small potential market right now. The payback time for this development will of course be longer, increasing the risk. We at Liebherr believe there is still some improvement in current equipment design that can be made to make it more efficient, instead of only focusing entirely on the idea that 'bigger is better'."