In response, mining companies are working to expanded equipment to met the market needs. Original equipment manufacturers are working to provide larger, more powerful equipment. However,as a result of increased sales, delivery dates on new equipment and parts are being pushed out, in some cases as much as two years.

These pressures mean that mining maintenance staffs have to focus on keeping equipment availability as high as possible everyday, and to ensure that the life of these machines is extended as production demands increase. Today, mining equipment is larger, faster and more technically advanced in the never-ending quest to move more material more cost effectively.

Missed opportunity is also expensive when equipment is down. Availability is extremely important to the bottom line. With the cost of haul trucks, bulldozers and other mobile equipment exceeding $1 million per unit, it is expensive to have equipment down and to replace machines premature. Any extension of machine availability or machine life represents significant cost savings to an operation.

In this competitive environment, key success criteria, such as field performance and customer satisfaction, must be maintained. Lubrication providers must be able to demonstrate measurable gains, in areas ranging from optimizing performance with the proper lubricant products, grades and quality, to extending in- use life and effectiveness. At many mining operations around the world, operators also want to see significantly reduced lubricant consumption, extended equipment component life and reduced environmental impact.

This article describes how Bel-Ray Co, Inc., a specialty lubricant company with over 40 years of experience mining lubrication, has applied a Total Lubrication Partnership program to effectively provide solutions to the mining industry. Components of the program include developing state-of-the-art lubricants, having a highly trained technical staff,and sharing best practices with the end user. The ability to show cost-saving benefits is a major part of this program, which can serve as a model for mining operations around the world.

Effective Performance

Surface mining shovels and draglines are some of the most heavily loaded mobile equipment in the world. There are multiple forces acting on many of the moving components simultaneously. Therefore, the lubricants used in these applications – on open gears, bushings, dipper handles, rails and rollers, and propel mechanism – will often need to have unique properties. For example, products have to balance tremendous extreme pressure capabilities with the ability to continuously lubricate during sliding and rolling actions. Harmonizing these lubricant characteristics has proven very tricky. Many times in an effort to improve one characteristic, the effectiveness of the other characteristics is reduced.

Effective complementary selection of premium additives and high-quality base oils can provide the basis for optimized lubrication of these applications – but such selection also must create measurabe value for customers, improving their maintenance budgets bottom line. One meaningful measure of this is equipment availability.

Equipment availability refers to the amount of time the equipment is ready to operate. The planned or budgeted hours that a piece of equipment is scheduled to operate in a given year varies with the mine plan. However, 6,500 hours per year is average, according to the mining industry. Ideally then, equipment availability would be 100 percent, meaning at the equipment washable to run for 6,500 hours. If availability were 95 percent, that indicates that the equipment was down as a result of unscheduled downtime and not able to operate for 325 hours (5 percent of 6,500 hours) during the budgeted year. Unscheduled downtime is most often due to electrical or mechanical problems.

Most mine maintenance professionals are able to place a dollar value on lost production or missed opportunity due to downtime. They use these numbers to calculate the cost-benefit of purchasing programs for new and improved equipment and products. This value varies with the type of mine, the mine plan and where the piece of equipment is operating.

For example, a copper or gold mine may place a cost of $5,000 per hour for shovels removing overburden, and $10,000 per hour for shovels loading ore. Coal mines might place a value of $2,000 per hour for shovels. Thus, in a given year a large mining shovel operating at only 95 percent availability in the ore body of a copper mine could have a lost production value of $3.25 million (6,500 x .05 x $10,000). An additional $650,000 can be added if the machine drops 1 percent more, to 94 percent availability. Its clear that the cost of superior lubricants with an advanced lubrication program, by adding percentages of availability, can be more than justified by the overall cost savings.

Save the Saddle Blocks

In 2003 Bel-Ray was contacted by a surface mine in Canada, in its start-up phase. It had three Bucyrus International shovels in operation and was experiencing failures to the saddle block bushing. The bushings were wearing to the point that replacement was required in as little as 1,300 hours. (Typical OEM recommended replacement hours are 12,000). With the repair cost averaging $80,000, this situation was not acceptable to the mine site management and the OEM.

A survey was conducted at mines operating this model of shovel. This information was compiled to compare the life they were getting on these saddle block bushings. Bel-Ray also ran a survey on like machines lubricated by Bel-Ray Molylube SF100. The research established the following performance data:

Bel-Ray Best: 34,628 hours

Bel-Ray Average (one mine, 13 sets): 15,439 hours

Bel-Ray Average (three mines, 16 sets): 15,033 hours

Industry Average: 8,000 – 12,000 hours

Industry Worst (6 sets): 3,000 hours

As this shows, the industry average is 8,000 to 12,000 operating hours between repairs, but the industry worst is barely a fraction of that. Meanwhile, Bel-Rays best performance was better than triple the industry norm, and it averaged 15,000-plus hours. The repair costs were also compared on a cost per operating hour basis (see table upper left).

This research showed that bushing life and the lubricant in use were linked. The answer, Bel-Ray suggested, was the effective use of a lubricant which has the ability to form and maintain a stable film within the application contact zone exposed to a wide temperature range, harsh environment and shock loads. The mine agreed that the differences in bushing life were at least in part due to lubrication, and Bel-Ray was given the opportunity at this mine to test against two other lubricant suppliers.

The test was initially set to run for 90 days, but at the end of 30 days the field performance justified the decision to immediately place Bel-Ray Molylube SF100 on all three machines. Because of the demonstrated component life, Bel-Ray lubricants also were selected when new machinery has been commissioned at this mine.

The bushings lubricated with Bel-Ray in 2003 are still in service, with four of five now exceeding 20,000 hours run time. It is very probable that the saddle block bushings on all five machines will exceed a service life of 25,000 hours. And as a result of this success, the expected bushing life of the shovel was raised from 12,000 to 16,000 hours by the OEM.

A final piece of the puzzle was to demonstrate the repair costs savings realized by extending the life of saddle block liners. Industry average cost is $8.00 per hour of operation, and Bel-Rays target is $3.33 per hour. The graph on page 36 illustrates the difference.

Striking Gold

In another case – a gold mining operation – optimized selection of a lubricant solved numerous problems inherent with many hydraulic mining shovels. Subsequently, a Total Lubrication Partnership developed that resulted in converting an entire fleet of both hydraulic and electric shovels to capture the operational and cost benefits.

In the late 1980s, Barrick Goldstrike, a leading gold producing mine located in Nevada, was experiencing inherent component failures on some of its hydraulic mining shovels. Shovel bucket and boom pins, as well as bushings, were being lost at an alarming rate. The tolerances between pins and bushings were very tight on these machines so that many conventional lubricants could not provide adequate lubricant film protection in the load zone. The mine was using the OEM-specified lubricant, so it was clearly an unacceptable situation.

Bel-Ray was asked to provide a suitable all-season grease with excellent pumpability, base oil penetration and antiwear properties to significantly reduce failures. The recommended product here was Bel-Ray Molylube 8626 EP Grease.

Failures were immediately reduced. The Bel-Ray product was able to penetrate the load zone and formed a tough lubricant film, reducing the metal-to-metal contact due to its use of superior base oils engineered with other formula components. As a result of this change and Barrick Goldstrikes superior maintenance program, the mine regained, and has continued to meet, its equipment uptime goals on its hydraulic shovels.

A Second Bite

The success of Bel-Ray field technical service problem-solving and the importance of a lubrication partnership was highlighted when Barrick Goldstrike started commissioning three P&H 2800XPA and one P&H 2800XPB electric shovels, circa 1988. These electric shovels have a payload capacity of 65 tons and an average dipper capacity of 44 cubic yards. The Bel-Ray field team, working with mine personnel, carefully considered the demands of the new equipment and the operating budget before selecting Bel-Ray Molylube Unee Lubricant 7060 (for the open gear applications), Bel-Ray Molylube 8626 EP Grease (for the bushings and roller bearing applications) and Bel-Ray 100 Gear Oil 90 (for all enclosed gear applications) in order to optimize performance and cost.

To date, all four of these P&H 2800 shovels have clocked over 100,000 machine operating hours, with two of them over 120,000 hours, without any lubricant related unscheduled downtime and extended intervals for scheduled downtime, thereby meeting the operational demands of the mine for nearly 20 years.

More recently, Barrick Goldstrike has sought much larger, faster and more powerful electric shovels as part of its operational fleet. Last December, for example, the mine operator commissioned a P&H 4100XPB electric shovel, one of the largest in the world, as part of its fleet for hard rock mining. This gigantic machine which has a working weight of approximately 3 million pounds and is equipped with a 73 cubic yard bucket able to move over 100 tons of ore in a single pass, is now field fit at the mine site. P&H has optimized the boom profile and arm for clearance and visibility, as well as efficient loading of wide, deep truck bodies. To date, while maintaining equipment uptime, the shovel has accumulated approximately 4,000 field operational hours without any lubricant related downtime.

The history of success of Bel-Ray products (proven in the P&H 2800-series and 4100XPB shovels) and their continual field support led to Barricks commitment to using Bel-Ray products throughout the new P&H 4100XPC electric shovel.

Lessons Learned

There is no substitute for using the highest-quality performance lubricants to get the best cost-benefit in mining operations. An effective lubrication partnership, between a mine and its lubricant supplier, that utilizes the supplier expertise and proficient field technical staff, enhances mine maintenance best practices.

The result, as Partners in Quality, Partners in Sucess, is continuous improvement in machine performance, equipment uptime, component life and more – all translating into significant and increasing cost savings at a mining operation.