In late 2004, Newmont Mining Corporation’s Minera gold mine in Northern Peru placed an order for its sixth EX5500 front shovel. This follows last year’s purchase of an EX2500 backhoe and five previous EX5500 shovel purchases – two in 2000 and three in 2001. The seven Hitachis form the loading-fleet backbone of this largest open-pit, heap-leach gold-mine operation in the world.
The shovels and the backhoe have been under a full Maintenance and Repair Contract (MARC) with Hitachi Construction Machinery America (HCMA) Peru since they arrived on-site. The MARC ensures high, guaranteed levels of mechanical availability at competitive rates. This agreement has been extremely beneficial for Hitachi, HCMA Peru, and Yanacocha – thanks to the excellent relationship that has developed among the three parties. In April 2004, another five-year MARC agreement was signed that covers the entire Hitachi fleet.
Yanacocha’s Maintenance Manager, Mike Wundenberg, says “HCMA Peru continues to provide a high level of performance under the MARC arrangement, and we have a very good working relationship. Hitachi has been very proactive in responding to problems.”
The life-to-date MARC and overall availability on the fleet have both been in the low 90-percent range. The mine plans to run the EX5500 shovels for about 90,000 hours.
The EX5500 shovels typically operate at an altitude between 11,800 feet (3600 meters) and 13,120 feet (4000 meters) – a height where most equipment struggles because of thin air. They usually load Caterpillar 793 haul trucks, although the mine operates a mixed truck fleet that includes 785s and 777s. This mixed fleet is a challenging legacy of the tremendous growth profile the mine has seen since production began in 1993. Depending on material density, the shovels five- or six-pass load the 233-metric-ton 793s and produce some 23 million dry metric tons each year. The EX5500s currently use 38-cubic-yard (29-cubic-meter) buckets and operate in bench heights of 33-40 feet (10-12 meters). A 40-cubic-yard (30.6-cubicmeter) bucket will soon be installed on one of the shovels that operates in lighter material, to improve the pass match. The EX2500 backhoe is used in both production and wall-trimming applications.
Yanacocha periodically tests the market with other Original Equipment Manufacturers (OEMs) for equivalent-sized loading units, or benchmarks production against other sites. Previous results of these exercises have shown the Hitachi machines to be frontrunners in price, productivity, and operating cost. Yanacocha’s decision to tap Hitachi for loading solutions is also influenced by the high level of factory and in-country support the site has received from both Hitachi and HCMA Peru. It also has a strong desire to standardize operating equipment as it moves forward to capture the operational and maintenance benefits from standardization to suitably sized mining equipment.
Asked whether Hitachi’s massive new EX8000 excavator has a future at the site, Optimization Superintendent Mark Jordan replied, “Possibly, if the machine proves to be productive and cost-effective, and can be configured to operate efficiently at high altitude. As a site, we are continually striving to improve operational performance and lower unit costs, and we expect the same from Hitachi.”
EX5500: Shovels One and Two currently have about 34,000 hours, Shovels Three and Four have over 26,000 hours, and Shovel Five has about 23,000 hours.