Secrets to Becoming a World-class PM Facility

A team effort at Cargill’s salt mine leads to reliability excellence.

The primary goal in any industry is maintaining safe, reliable equipment. This involves getting the maximum uptime at the lowest cost of operation and extending the as-designed usable life. The fundamental cornerstone of this proposition is effective lubrication in concert with preventive and predictive maintenance tasks that are carried out in a quality manner.

Performing required lubrication in a proper manner is challenging in even the best conditions, but at Cargill Deicing Technology’s rock salt mine in Cleveland, Ohio, the obstacles were considerable. The mine is 1,800 feet deep and extends approximately 4 miles under Lake Erie. The underground mining operation utilizes a room-and-pillar style of mining, and its business is dependent on Mother Nature, since the primary product is deicing salt used for keeping roadways and sidewalks ice-free.

The mine maintains a fleet of specialized mobile equipment that extracts the salt, which is transported on a conveyor system to the milling operation and then hoisted to the surface for distribution. Diesel-powered mobile equipment is used for the extraction process. These machines are high oil consumers that require 250-hour operational oil changes.

Cargill Deicing Technology’s rock salt mine in Cleveland, Ohio, is 1,800 feet deep and
extends approximately 4 miles under Lake Erie.

The maintenance team made best-practice theories a reality by constructing a world-class, all-inclusive preventive maintenance (PM) facility, which is a unique installation for any underground mine. Considering all the challenges they had to overcome, the employees rose to meet and overcome those problems with very successful results, thanks in large part to having an engaged workforce and proper training.

Old Practices

Approximately 10 years ago, the mining operation performed equipment servicing and PMs where the equipment was parked. All the material was brought to the machines, including filters, oils, drain pans, supplies, etc. Oil was transported in generic cans that were filled at a bulk station. The top of the can and equipment fill point were wiped off to keep dirt out when new oil was added to the machine. Waste oil was collected and poured back into the same cans to be dumped in the bulk waste-oil container, which was sent back to the surface for recycling.

Previously, Cargill performed equipment servicing and preventive maintenance where the
equipment was parked. Oil was transported in generic cans that were filled at a bulk station.

Oil samples were taken, but maintenance personnel didn’t understand the value, since they did not receive any feedback and no actions were generated as a result of the samples. Once the oils were drained, there was an ongoing question of what product should be used for refilling.

Beginning the Improvement Process

With so many issues at the mine needing improvement, the question was where to begin. It was determined that the best starting point would be to develop the knowledge base of the maintenance personnel. Part of this development was to have each mechanic attend a three-day lubrication course, which was conducted onsite. This helped provide the fundamental understanding that every component requiring lubrication needs the correct lubricant applied in the correct manner in the correct amount at the correct time. When these four principles are followed, equipment can last almost indefinitely.

Of course, acceptance is not always easy when conducting this type of training with long-time employees. About a week after the training, one veteran mechanic requested a lubricant specification book because he believed an incorrect lubricant was being used for an application. This was a major accomplishment. Having a highly seasoned employee requesting clarification meant he not only understood the class, but he also was applying what he had learned. This was a good first step.

Creating a New PM Bay

With a workforce that is engaged, employees execute what they learn when they understand why. Maintenance personnel soon began questioning current practices and believed they could make improvements, such as building a PM bay. Working with a maintenance supervisor, they decided what should be included in this area. They wanted to be able to perform PM inspections and kidney-loop filtration of systems, not just service equipment.

With a plan in mind, the team started assembling the necessary components. A location near the shop was designated as the PM bay area, and construction soon began. Once completed, the PM bay featured all the necessities for oil storage, pumping and filtration. Safety items were added such as an overhead fall-protection restraint system when accessing the top of the equipment.

Salt is loaded onto a conveyor system for transfer to the milling operation, which crushes
and screens the salt into a usable product before transporting it to the surface.

As the PM bay was put into use, employees became proud of their accomplishment. Although it was not much to look at, it was a major upgrade from what they had been doing. Functionally, the PM bay achieved its intended design of supplying clean, filtered oil to the equipment. More importantly, the improvement came from the workforce wanting to be more proficient. This created a culture shift. Performing PMs where the equipment was located became a thing of the past. Everything now came back to the PM bay, and workers performed PMs with greater care, which translated into better equipment availability.

Continuing to Improve

Mining is an ever-moving operation. As the mineral is extracted, the distance from any permanent location increases. Soon, the PM bay became one of those locations getting farther away. Moving equipment to the bay took longer, leaving less actual PM time.

A suggestion was made to move the PM bay closer to the working face, which would mean more time with the equipment. This was a great idea, but it was a monumental task to disassemble the current PM bay and reassemble it in a new location while managing the required day-to-day maintenance activities.

Then a question was asked: “What if the PM bay was portable so it could continually advance with the faces?” This began a quest to find a supplier that could build a rugged, portable lubrication containment for an underground mine.

Employee involvement was critical. The site lubrication team, mechanics and maintenance apprentices who performed the equipment PMs were asked what they would like to see in this portable lubrication containment. Some of the suggestions were:

• Hose reels on all oil products
• Hose reels inside but nozzles outside the containment
• Everything pneumatically operated (no electric pumps)
• Waste-oil pump to be high volume and discharge into waste-oil container
• One waste-oil container outside each containment with easy change-out
• Kidney-loop filtration built in with quick disconnects
• Filters to include bypass indicators
• All filters and pumps the same
• 110-volt receptacles inside and outside
• Internal lighting
• A desktop area inside to complete paperwork
• A fold-down desk area outside for diesel particulate matter (DPM) testing
• Storage cabinet for additional filters, tools, test equipment, etc.
• High-volume compressor to clean out radiators
• Air hose reels in both containments with 100-foot air line
• An additional tank and pump in each containment for future expansion
• Runners underneath containment to facilitate easier moving over rough terrain

When the completed drawings were presented to the lubrication team, mechanics and apprentices, they were pleased everything was included and made only a few suggestions for improvements. This core group was truly engaged in the process. They made a difference, and their ideas were put into practice. They now not only had ownership of the lubrication containment but also enthusiasm in how they performed their work.

Combined employee ideas culminated in the creation of a new PM facility, which
featured all the necessities for oil storage, pumping and filtration.

This enthusiasm was contagious, as others started making suggestions on how to improve the PM process. One idea was to have a level concrete pad on which to park the equipment when doing PMs. This would allow for proper oil fill levels and provide safer footing around the equipment.

Another suggestion was to wash the equipment close to the PM bay in order to eliminate travel time. This posed several challenges, since water dissolves salt and keeping the PM area clean was a priority. One individual’s solution was to create a concrete-lined sump to catch all waste water from the washing process for recycling. This used water would be pumped into a containment tank to water roadways for dust control and improve ventilation.

These combined employee ideas culminated into making the PM facility. The entire 40-by-160-foot work area was made of concrete, creating a safer work environment and improving PM quality. However, this was a major undertaking and required a lot of hard work. The concrete had to be lowered underground, transported to the site as a dry mix, mixed onsite, poured and finished by a crew of volunteers from the maintenance team. This illustrated their belief in the project and their commitment to making their ideas become a reality.