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MAINTENANCE Leveraging Lubrication It's a time-worn adage, but still true: pay now or pay later. When it comes to proper lubrication of mine equipment, a few dollars spent now can help avoid major unplanned costs in the future. Cutting Consumption, Raising Productivity Haul trucks, in particular, can challenge the protective qualities of even premium engine lubricating oils. Long uphill hauls at full load can elevate oil temperatures to damaging levels, resulting in possible additive depletion, oxidation, varnishing, corrosion and increased frequency of oil changes. Mine operators—pressured on one side by rising material and labor costs, and on the other by softening commodities markets— are naturally interested in getting the last ton of productivity out of their primary fleet equipment, at the lowest operating cost. Under these circumstances, it's tempting to consider measures that could lead to lower expenses for two of the major consumables involved in loading and haulage: fuel and lubrication products such as engine oil. But when it comes to lubrication, cutting corners—extending oil change intervals, using cheaper filters, or simply ignoring oil condition, for example—can result in false economies. As the following case histories illustrate, real savings are often generated by investing attention and relatively small amounts of money to maintain proper lube standards and service, avoiding the much larger costs of premature engine overhauls, unscheduled downtime and failure to reach projected equipment service-life goals, among others. 82 E&MJ; • JUNE 2013 ExxonMobil recently reported that the introduction of its synthetic heavy-duty diesel engine oil, Mobil Delvac 1 ESP 5W-40, had resulted in significant performance benefits for a Mexican mining customer, including the reduction of oil consumption and the extension of oil drain intervals. Newmont Mining Corp. holds a 44% ownership interest in the open-pit La Herradura gold mine, located 250 miles (400 km) south of Mesquite in the northern Mexican state of Sonora. Fresnillo plc owns the remaining interest in the mine and is the operator. Construplan, the mining contractor, operates more than 40 pieces of heavy-duty equipment at La Herradura, ranging from haul trucks and excavators to heavy-duty pickup trucks. This equipment encounters extreme temperatures ranging from 50°C (125°F) in the summer to -10°C in the winter (-14°F). ExxonMobil said that after switching to Mobil Delvac 1, Construplan reported benefits that include enhanced equipment performance, increased uptime, improved fuel economy and extended oil drain intervals when compared to conventional mineral oils. As a result, Construplan has been able to reduce oil consumption, minimize used oil waste, and maximize the overall productivity of its equipment and people. Mobil explained that its Delvac 1 heavy-duty engine oils are part of a mining-focused product line that includes Mobil SHC synthetic oil and greases, and Mobil DTE Series high-performance hydraulic fluids. These products, according to the company, can deliver a range of performance benefits, including prolonged equipment life, improved energy efficiency and extended oil life when compared to conventional mineral oils. "With mining equipment often subjected to extremely heavy loads and operating in challenging environments, mine operators can sometimes find it challenging to find the right solutions that will help enhance efficiency and increase productivity," said Umut Urkun, industrial lubricants marketing advisor—Europe, Africa and Middle East, ExxonMobil Fuels and Lubricants. "We have worked closely with mining professionals for more than 50 years to obtain the necessary insights required to formulate products that help to maximize productivity in a safe and costefficient way." Results from Ray Across the border from Sonora, Grupo Mexico's Asarco Ray operations are located 64 miles southeast of Phoenix, Arizona, USA. The Ray complex comprises a 250,000-t/d open-pit mine with a 30,000-t/d concentrator, a 103-million-lb/y solvent extraction and electrowinning operation, and associated maintenance, warehouse and administrative facilities. The mine operates a fleet of 39 haul trucks, 21 of which are Liebherr T 282s. These 400-ton ultra-class trucks, powered by 20-cylinder MTU diesels, operate 22 hours a day, seven days a week, in harsh and often extremely hot conditions. Asarco Ray www.e-mj.com