FUELS AND OILS number, the higher the amount of varnish precursors present in the oil.
ANAC( ANAlysis Compared) is a service of TOTAL that provides a complete range of analytical monitoring systems for in-service oils, available for any automotive and industrial application. For management and technical monitoring of mining, construction and transportation vehicles as well as industrial equipment, ANAC offers a full range of in-depth analysis processes for in-service oil including Membrane Patch Colorimetry.
ExxonMobil on better oils management
Advanced lubricants and greases play a crucial role in ensuring the consistent protection and performance of mining equipment, helping safeguard against financial losses and safety risks. However, constant exposure to the elements, extreme temperatures and heavy loads present a unique set of lubricant challenges. Sarp Degirmenci, EAME Offer Advisor at ExxonMobil, offered some insights on how best to choose and use lubricants:“ Synthetic and mineral lubricants are both made from crude oil but synthetic products are formulated using more advanced refining processes, which have higher purity and quality. This means they can deliver a range of performance benefits including longer oil life, wider operating temperature range, resistance to deposit formation and enhanced wear protection.” Taken together, these benefits can help extend equipment life.
One of the key considerations when choosing a lubricant is its viscosity. Getting this wrong can increase equipment wear and energy consumption, while reducing lubricant life.“ When temperatures rise, viscosity falls, and when temperatures drop, viscosity increases. The degree to which this happens to an oil is called its Viscosity Index( VI). A low VI can result in an oil having insufficient resistance to temperature changes, which can have a detrimental effect on its performance and can result in costly and avoidable wear. Synthetic lubricants with a high VI can help protect mining equipment across a wide range of operating conditions.”
Most applications have specific viscosity requirements, so mining operators should always check original equipment manufacturer recommendations. However, it also advisable to talk to oil supplier’ s field engineers in order to ensure the use of the best performance lubricants. Lubricants can also help protect against cold start issues.“ Mineral oils are especially prone to increases in viscosity when temperatures fall. When this happens it compromises a lubricant’ s ability to perform, which can lead to start-up wear and costly maintenance issues. Synthetic lubricants can be formulated to resist a change of viscosity in extreme temperature conditions – both low and high. Your lubricant supplier will be able to recommend oils suitable for low temperature applications.”
Specialist lubricants are engineered to help optimise the performance and productivity of mining equipment.“ For example, high performance hydraulic oils can improve the cycle efficiency of shovels, excavators and haulage equipment while helping cut energy consumption and maintenance issues. Tests have shown that a switch to Mobil DTE™ 10 Excel can provide up to 6 % efficiency gain in hydraulic pump performance.”
Lubricants can also help ensure the efficient running of compressors, open gears and mobile mining equipment, even in harsh environments. Doing so can contribute significant savings to a mine site operation.“ For instance, a Brazilian mining company saved $ 4.2 million over four years by switching to high performance synthetic grease, Mobilith SHC™ 220. The lubricant helped extend roller bearing life on a fleet of 19,000 open gondola cars by 43 %. Similarly, an open pit mine in the US saved more than $ 2.1 million annually by switching almost 50 of its CAT haul trucks to the high performance synthetic gear and bearing oil, Mobil SHC™ 630. The lubricant helped optimise the performance of the CAT 793 trucks, leading to a 5.5 % increase in fuel economy and 326 hours more in-service time, contributing to enhanced on-site safety.”
Finally, the use of a high performance lubricant can enhance equipment reliability and increase re-greasing and oil drain intervals. This cuts the need for hands-on maintenance, which decreases the potential risks for employees by limiting human-machine interaction. It also helps reduce the possibility of lubricant-related spills and leaks.
Regular used oil analysis, such as ExxonMobil’ s Mobil new Mobil ServSM Lubricant Analysis( MSLA), can help reduce unscheduled equipment downtime. The information it provides can help users detect problems, such as contamination, deposit build-up and wear, before they become a problem, improving equipment reliability.“ With 25 testing options available, users can pick and choose the right test package for their operation. ExxonMobil also offers access to its technical service engineers 24 / 7 as part of the service. Routinely implemented, this enables mine operators to track lubrication trends and spot anomalies, such as changes in viscosity. These insights can help users take corrective actions, which can then be monitored by scheduled sampling backed up by ExxonMobil’ s technical expertise.”
DYNAVIS ® fluids proven in Indian test
DYNAVIS ®-formulated hydraulic fluids from Evonik can improve efficiency and cut down on fuel consumption. In the coal mines and quarries of a leading Indian energy company near the city of Ranchi, hydraulic mining excavators extract coal and remove roofing slate. With the DYNAVIS ®-formulated fluid tested against a reference fluid under realistic and challenging mining operating conditions, slightly lower peak oil pressure accompanied by less frequent pressure peaks within the hydraulic oil system were observed.
This saves energy and reduces, at stress phases, the temperature increase of DYNAVIS ®- formulated hydraulic fluid in comparison to the reference fluid – and, in general, to every conventional fluid.
After idle times or engine stops, lower temperatures and reduced pressure increases could be observed. A hydraulic fluid, subjected to less temperature stress, suffers less wear and tear, contributing to a longer service life, thus substantially extending service intervals. As much as a doubling of service life looks achievable with the use of DYNAVIS ®-formulated hydraulic fluid.
With the DYNAVIS ®-formulated fluid in its hydraulic system, the large excavator moved 12.2 t of roofing slate per litre of fuel. With the reference fluid, the ratio was just 10.8 t. This equals an efficiency gain of 12.4 %. Trip and time efficiency also improve. While the articulated trucks are filled faster due to a more agile excavator, thus speeding up the trips for every loading cycle, the excavator burns less fuel, resulting in more efficiency. These results come with a confidence interval of 80 to 90 %.
The initiator of the test was a leading oil company- a DYNAVIS ® licensee, supplying the entire Indian market. The excavator in question weighs 111 t and comes with 567 kW of engine output. 1,100 litres of hydraulic fluid are circulating in its hydraulic system. As usual in the mining industry, the excavator is operated almost continuously, in a three-shift service. When digging or loading, fuel consumption of more than 70 litres of diesel fuel per hour is recorded. Depending on the task and working conditions, this rate can vary widely.
The hydraulic fluid test regimen was planned, conducted, and evaluated by the Evonik Performance Test Laboratory. The reference hydraulic fluid of the large excavator was exchanged with a DYNAVIS ®-formulated fluid – followed by the return of the reference fluid to complete the measurement process. Over the course of the day to day mining operation, 19 shifts were observed and recorded. The test was conducted under typical working conditions. Several dump trucks were deployed for the monitored excavator, carrying away about 75-85 t of roofing slate per truck trip to achieve the scheduled shift productivity. IM
JULY 2018 | International Mining 43