The world is still primarily reliant on fossil fuels for energy generation.
With billions of people across the globe, this means the demands that are placed on the mining industry are huge. Extracting these fossil fuels as efficiently as humanly possible is of utmost importance, and for best efficiency and ability to meet this demand, you need scale. And the five machines featured across the next six paragraphs definitely fit the bill scale.
This is huge-scale engineering that you can barely get your head around. It’s difficult to get your head around just how vast these massive tools are – not to mention the sheer amount of fossil fuels they extract each and every day, around the clock.
They may cost tens of millions of pounds, and last for decades, but when it comes down to it they are still controlled by a human being. The principles they use will be familiar to those who have driven past roadworks or looked closely at a building site. It’s just that they are enlarged to dimensions to take your breath away. Read on to find out how they work.
Biggest Dragline – Bucyrus 8750
This massive dragline can clear football pitch-sized spaces right before your eyes.
The Bucyrus Dragline 8750 will run 24 hours a day, seven days a week, and excavate up to 116m3 per scoop – that’s the equivalent of 58,000 two-liter water bottles. It will do this for an average of 40 years, which is why it’s used in surface mining operations worldwide. There are 45 different specifications of dragline, each with its very own on-staff application engineer.
The 8750 series has multiple bucket capacities, and a boom length of up to 132.5m. It can reach depths of up to 79.8m. It is among the largest of all mobile equipment in the world; but when we say mobile, we do not mean fast! Moving a dragline is not the work of a moment, particularly the Bucyrus. It has a rated suspended load of up to 344,736kg and its approximate working weight is more than 7.5 tons.
It is powered by Siemens AC drives throughout. The 8750 series comes in various guises, with the range-topper being the 8750D3. This uses gearless AC direct drive for hoist and drag – the advantages here are in efficiency. It allows fast bucket fills, and the lack of hoist and drag gearing also reduces maintenance.
Power is provided to the AC drives by utility lines -the enormous power consumption means that connection directly to the electrical grid is often the most efficient solution.
Biggest haul truck – Liebherr T282C
The word ‘supertruck’ is not enough to describe the ‘ultratruck’ behemoth that is the Liebherr T282C, which is used in mining operations worldwide. Its sheer scale can be judged by its empty weight of 266 tons – or more than 150 Ford Focus hatchbacks piled together. Not only that, but it’s also capable of carrying a 400 ton payload on top of this, giving it a weight of over 600 tons when full!
Powering it is a diesel engine that comes in either fuel-optimised or emissions-optimised setup. As with passenger cars, achieving lowest-possible exhaust emissions carries a fuel usage penalty. It has up to 20 cylinders and a 95.4-litre capacity; maximum power is 4,023bhp! The engine alone weighs 12 tons. It delivers energy to an alternator, which powers a liquid-cooled control box – this converts it into three-phase AC current.
It is moved by an AC electronic drive system called IGBT – insulated gate bipolar transistor. This uses in-wheel induction motors to move the monster truck. They allow the diesel to run independently of travel speed, therefore generating drive in the most efficient way possible. This gives better fuel economy.
The IGBT drive system can also slow the big truck down instead of using the back-up disc brakes. This regenerates electrical energy, which is used to power the truck’s auxiliary systems – it is hybrid-style ecological awareness!
Road construction dumper truck drivers will find the cabin of this beast fairly familiar: it has a traditional steering wheel and pedals, and the left-hand-drive set-up includes a 30-cm colour touch screen for diagnostics. Its top speed is 64km/h (40mph) and the clever drive system even aids handling. In corners, drive to the outside rear wheels is increased and eased off on the inside wheels, helping it turn in better.
The T282C is constructed using a vertical integration process. On the cast truck frame sits the massive dump body, superstructure and drive train. Liebherr has optimised it using computer aided design, so reinforcements are only added in high stress areas. This has cut weight and also improved the maximum payload. The dump system is controlled using a joystick and completes a lift cycle in under 50 seconds. Fully lifted, the dump body stands nearly 15m high.
Biggest wheel loader – LeTourneau L-2350
To clear large spaces fast, you need a LeTourneau L-2350. It’s the world’s biggest wheel loader, and is more than 20m long. The wheelbase alone is the length of two large executive cars, and the bucket is so big it is nearly a metre wider than the wheel loader truck itself. It is driven by a choice of several diesel engines, depending on the type of material to be excavated – it is highly flexible but used mainly in coal mining. The largest engine is 45 litres and puts out 2,300hp.
Maximum speed is 17km/h (10.5mph), both forwards and backwards; an AC-DC traction drive uses four traction motors with infinitely variable speed. Braking is electronic and the
L-2350 is steered by a joystick. Excavation operations use an electrohydraulic hoist and bucket; the best-match truck capacity is 400 tons and larger! As it operates in mines, all air is filtered and supplied to the engine, drive system cooling and also a pressurised cabin. Operators have a colour-coded warning light system that alerts them to engine, hydraulic, electrical and electronic problems.
The operating payload is vast, up to 72,574kg in standard form, and only slightly reduced at 68,039kg in high-light form. As standard, it has a reach of 3.18m, with the high-lift increasing this to 3.49m (and a total height of 13.89m).
Biggest hydraulic loaders – Terex RH400
In front of you is the world’s largest hydraulic excavator – an USD 11m machine that stands a full ten metres (33 feet) high and 8.6 metres wide. The record-breaking Bucyrus is used for many mining operations, including coal, copper, iron ore and oil sands; it is commonly found in Canada, but also has an underground coal mining specification.
The Terex RH400 weighs an incredible 980 tons and is powered by two turbodiesel engines with a maximum output of 4,500bhp at 1,900rpm. Each is 60.2 litres in capacity and has 16 cylinders; they use two-stage turbocharging, aftercooling and intercooling.
The engines power hydraulic pumps, which generate very high pressure oil for driving the track motors and moving the excavator rams. There are eight main pumps and six swing pumps. Forward drive is via axial piston motors on each side; each track is two metres wide and three metres high. The total hydraulic oil volume is 13,000 litres; an electronic Pump Managing System oversees the hydraulics and incorporates flow-on-demand control.
Excavators are built of two distinct constructions – the undercarriage and the house, where the operator cab and boom reside. They fit to the undercarriage using a centre pin, meaning they can rotate 360 degrees. A torsion-resistant 9.5m-long boom and 56m-long stick provides the excavation shoveling duties; the bucket is attached on the end. The RH400 has a bucket capacity of 50m3, and various specifications are available, depending on shoveling duties: iron ore, heavy rock, oil sand and standard rock configurations are offered. Up to 3,300kN of digging force can be generated.
It achieves considerable bucket load without significant counterweights at the rear. This means it is relatively compact, which is an important consideration for use in space-restricted areas. The operator also has a comfy cabin with pneumatic seat and ergonomic joystick control system. The windscreen is armour plated and a safety switch is embedded inside the seat: when it senses it is unoccupied, all the hydraulic controls are automatically neutralized.
Biggest rope shovel – P&H 4100XPC
Rope shovels are the heavy-duty attackers of the mining industry – and none eat away the earth faster than the P&H 4100XPC. This is the supercharged high-performance pinnacle of the rope shovel world!
A rope shovel is used for digging out surfaces such as vertical coal faces. They consist of a rotating deck where the driver cabin lies, along with the engine and a heavy counterweight. To the front of the deck a boom is attached, which carries a swing arm and a bucket.
The bucket is controlled by a series of ropes. When facing a surface to be excavated, the wire ropes are dug into the surface using a crowd arm, then pulled up through filling it with material. Once raised clear, it swings to one side and can be released into a dumper truck. P&H has cut seconds from this entire cycle with its ultra shovel. How? Through speeding up the hoist cycle by extending the shovel’s speed range.
This has come at no penalty to capacity or payload, though. The nominal payload is 115 tons, and it can cut up to 16.8m high, through a radius of 23.9m. This is why the operator sits a full ten metres off the ground; the rope shovel itself is 14.7m high, and 15m long. The wire hoist rope alone is 73mm thick!
There are two hoist motors, rated at a peak 3,990hp, three swing motors, two propel motors and a single crowd motor. The operator controls it via an armrest-mounted pistol-grip joystick.