OPEN-PIT MINES Upgrade Fleets with Ultra-Class Haulers

Engineering and Mining Journal, Aug 2004

Five years after it launched the 360-ton ultra class T282 haul truck, Liebherr debuted the second generation haul truck, the T282B, at Bauma Mining 2004. Using the experience it gained having more than 40 T282 haul trucks in the field, the German-based company with production facilities in Newport News, Va., incorporated its field data into the new design. Recently, the company announced that it had sold eight of the new T282B haul trucks to the Cortez gold mine in the United States. This fall, the truck will make another appearance at MINExpo 2004 INTERNATIONAL in Las Vegas, Nev.

One of the first mines to order the original T282 haul truck was Codelco's Chuquicamata mine in Chile. In 2002, the mine added 17 Liebherr T282 haul trucks to its fleet, which works at an altitude of almost 3,000 m in the Andes hauling copper ore. In addition to those extreme conditions, the trucks have also found homes in equally harsh conditions mining tar sands in Alberta, Canada, and in South African iron mines.

The improvements Liebherr made to the T282B haul truck took its payload capacity from 360 tons (327 metric tons) to 400 tons (363 metric tons). In addition to the greater production capabilities, the manufacturer also incorporated several features that will improve safety and ease maintenance.

Earning Recognition in South America

In 2001, as part of Codelco's continued expansion at Chuquicamata, management determined that larger capacity haul trucks were needed. The specification set by the mine required that the trucks would be able to maintain a minimum speed of 6.2 mph on an effective grade of 11.5% while carrying a payload of 360 tons. Due to the depth of the pit, the round trip cycle time exceeded one hour with the trucks spending 45 minutes on grade.

Liebherr determined that the 360-ton payload could be achieved with a Conymet HE lightweight dump body, which would reduce the gross vehicle weight. The trucks were manufactured in the United States and then shipped to Chile to be fitted with the bodies. The HE bodies were fabricated at Conymet's plant in Antofagasta, Chile.

The first order of 10 T282 haul trucks was completed in early 2002 and a second delivery of seven tucks followed. The first 16 were delivered with 2,700-hp Cummins QSK 60 engines. The one exception had a 3,650-hp DDC-MTU engine.

At the time, Chuquicamata's in-pit crusher was the largest in the world, processing more than 11,000 tons per hour. The trucks deliver copper ore to the crusher from the pit. A set of P&H 4100XPB shovels, equipped with large buckets for high loading capacity, fill the trucks in three or four passes.

Recognizing the need for on-site service, Liebherr established a new subsidiary, Liebherr Mining Chile Limitada (LMC) to support the T282 fleet. The on-site facility includes parts warehousing and service facilities staffed with service technicians and administrative personnel.

Because of the altitude and location, the Chuquicamata mine is considered one of the harshest environments in which to operate equipment. According to Liebherr, Chuquicamata's T282 fleet has not been affected by the altitude with respect to engine performance and as a result no derating has been needed on either the Cummins or the DDC-MTU engines.

The World Gets a Glimpse of the T282B in 2004

The star of the Bauma 2004's outdoor exhibit was Liebherr's new T282B haul truck. The company spared no expense floating the ultra class haul truck across the Atlantic Ocean to the mining and construction trade fair in Munich during March. In what may have been the first time a truck of this magnitude set foot in Europe, it dominated the venue.

The truck's physical dimensions, 7.4 m (24 ft, 3 in.) high, 8.8 m (28 ft, 10 in.) wide, and 14.5 m (47.5 ft) long, make it the largest two-axle mining truck in the world, according to Liebherr. More than 200 improvements in many areas have been incorporated into this new model. Aside from increasing its payload, the engine is 35% more powerful. It travels at a maximum speed of 64 km/h (40 mph), while its radial, low aspect-ratio tires and nitrogen-oil suspension offer an added level of ride comfort.

Since the rotors are the only moving parts of the Liebherr-Siemens AC drive, the AC alternator and travel drive motors are virtually maintenance free. Each wheel motor has its own inverter to allow for totally independent power supply to either set of rear wheels. The drive system is controlled via fast solid-state electronics, which have no moving components.

Lighter than either a DC or a mechanical drive, an AC drive system allows for better payload to vehicle weight ratios, stronger acceleration, and faster travel speeds, according to Liebherr, which results in shorter cycle times and lower cost per ton moved. Mining companies find these advantages appealing and the T282B prepares to make its mark in open-pit mining with the lowest operating costs per loaded ton.

Cortez Orders Eight Tz8zBs

A 60:40 joint venture between Placer Dome, Inc., and Kennecott Minerals Co. in central Nevada, the Cortez mine uses carbon-in-leach, oxide heap leach, and roasting technology to recover gold. Located near Crescent Valley about 75 miles southwest of Elko, Nev., Cortez produced more than 1 million oz last year. During 2004, gold production is targeted at approximately 940,000 oz with a higher percentage of total production coming from heap leach (46% vs. 31%) than the mill (61% vs. 46%), due to significantly lower mill grades.