Mining companies invest huge sums into their equipment, which needs to deliver high output round the clock. Planned maintenance plays an important role in sustained reliability and many companies rely on it to deliver continued productivity. Sulzer, while perhaps better known in mining for its global pumps business, operates major service centres in Gillette and Phoenix in the US that offer the overhaul of wheel motors as well as recently introducing exchange units, which minimse both downtime and investment for the customer.

Heavy haul trucks are the workhorses of the open-cast mining industry. Capable of transporp to 400 tons of ore, coal or overburden in a single load, these trucks are fundamental to the productivity, and profitability, of mining operations. However, keeping spare parts for these huge vehicles can involve a considerable investment. Each haul truck uses a pair of wheel motors, which weigh around 16 t each and cost $1.3 million to replace.

Since the 1980s, Sulzer’s Gillette Service Center in Wyoming has specialised in the maintenance and support of complex mining equipment. The Powder River Basin area around Gillette is the largest coal producing area of the US, home to around 40% of total domestic production. At the same time, the Phoenix Service Center in Arizona supports the copper mining business, which delivers over 50% of copper mined in the USA.

At both the Gillette and Phoenix sites, the company has invested in the skills and equipment necessary to complete the most complex wheel motor repairs, from rewinding motors to manufacturing obsolete or difficult-to-source replacement parts on its in-house CNC machines. Both facilities have also built a dedicated test stands for wheel motors, allowing refurbished units to undergo comprehensive quality checks, including temperature and vibration measurement, before being returned to service.

Repairing and reconditioning haul truck wheel motors is a significant undertaking. A basic overhaul requires around 400 hours of work by skilled technicians. If the unit has suffered a major failure, the work can extend to 800 hours. For Sulzer customers, however, a complex repair doesn’t have to mean extended downtime. The service centres now run an exchange program for GEB25 and Y106 wheel motors, the two most common types used on Komatsu haul trucks.

When a wheel motor needs planned maintenance, a fully overhauled and tested unit will be delivered to the customer’s site and exchanged in the field. That process takes just a few hours, allowing the customer to get the truck up and running with the minimum of downtime. Back at the service centre, every wheel motor goes through a complete strip down and inspection process. The center uses advanced computer-controlled metrology equipment to verify the condition of components and customers are involved in key decisions about whether to repair or replace critical parts.

The service centres keep an extensive inventory of components for wheel motors, generators and other haul truck systems. They use their knowledge of customers’ fleets to forecast demand for wear-prone items such as bearings and gears, and to ensure they have access to hard-to-find parts or those with long lead times.

Decades of experience enable design improvements to be proposed and implemented to increase reliability, enhance serviceability and extend the operating life of refurbished units. The success of the exchange program for Komatsu trucks has created interest from other mine operators in the region, and Sulzer is currently investigating the feasibility of extending the service to other models.

“We have long been proud of our ability to tackle the most demanding technical challenges in mining equipment repair and overhaul,” says Todd Colbrese, General Manager at Sulzer Gillette Service Center. “With the exchange program, we can also make a big difference to our customers’ primary business challenge: maximising the availability and productivity of their assets.”