Rebuilding machines deep underground: Cat dealer delivers a maintenance solution for Cargill’s Cayuga salt mine
Cargill Deicing Technology’s Cayuga mine is located 701 meters (2,300 feet) under a picturesque lake in New York, USA. Getting parts and machines into the mine can be a challenging endeavor. In fact, when it’s time to repair or replace large pieces of equipment, they must be dismantled above ground and then reassembled in the mine.
As the Cayuga mine sought to improve the performance of its fleet of Cat® R1700G load-haul-dump loaders, dealer Milton Cat developed a solution to make the mine’s LHDs more productive and reliable — at around 60 percent of the cost of buying a new machine. And they would do it without ever removing the machine from its underground home.
The solution was to perform Cat Certified Rebuilds (CCRs), which takes advantage of the “second life” built into the Cat LHDs. And for the first time ever, the rebuilds would be completed underground — a challenge that has been proven possible and that is now a recognized solution for other underground fleets.
Producing salt for winter road safety
Cargill Deicing Technology is a division of Cargill, an international producer and marketer of food, agricultural, financial and industrial products and services headquartered in Minneapolis, Minnesota, USA. Cargill Deicing Technology offers bulk deicing salt, enhanced deicers, automated brine production systems and other winter maintenance equipment to improve winter driving safety.
The Cayuga mine produces primarily road salt, the majority of which is sold in the northeast United States from November through March. Mining began at this location in 1919 by Cayuga Rock Salt Company. Cargill purchased the facilities in 1969 and is sole owner of the operation.
The Cayuga mine is located in the picturesque Finger Lakes region of New York, directly beneath Cayuga Lake, about 9.7 kilometers (6.0 miles) north of Ithaca, New York. At 64 kilometers (40 miles) long, Cayuga is the longest of the Finger Lakes. The mine is located at the southeastern end of the lake, which is 4.8 kilometers (3.0 miles) across at its widest point. Mining is done 701 meters (2,300 feet) under the lake within the lake perimeter.
Finding salt deep underground
The Cayuga mine is located in deep sedimentary deposits that were laid down in a large oval basin extending through much of the northeast and Midwestern states. The mine, which is the deepest salt mine in the western hemisphere, is near the center of the basin where the deposits reach 2 135 meters (7,000 feet.) The sedimentary beds dip slightly toward the center and increase in thickness toward the center of the basin. The rate of dip is about 42 meters per kilometer (85 feet per mile). Shales and sandstones account for most of the layers, with limestones, dolomite and Silurian age salts also encountered. The salt zone ranges in thickness from 61 meters (200 feet) at the edges of the basin to 350 meters (1,150) feet at the center.
Salt beds occur at depths between 594 and 835 meters (1,949 and 2,741 feet). The salt beds were laid down by evaporating sea water pools almost 600 million years ago; the formation itself is called an evaporate.
The mine contains eight salt beds, or layers, and Cargill is currently mining in the sixth layer — a relatively flat layer near the bottom of the salt sequence that has an estimated remaining life of 40 years. Over the life of the mine there have been three working levels — No.1, No. 4 and No. 6, which began being mined in 1969. It is a flat formation ranging in thickness from 2 to 4.5 meters (7 to 15 feet), dipping slightly in a southeasterly direction. The surrounding geology and the shape of the beds are similar to that of coal beds, which makes it ideal for room and pillar mining. The mine produces 2.3 million tonnes (2.5 million tons) per year and has a work force of over 200 employees producing 8 160 tonnes (9,000 tons) per day.
The system is nearly 10 kilometers (6 miles) of 3-meter-tall (10-foot-tall) corridors with 12-meter-wide (40-foot-wide) rooms. The No. 6 layer is mined in an organized, highly mechanized manner. Mining is currently moving northward under Cayuga Lake. The main travel and airways are running north to west with production panels branching off to the east and west.
Three shafts serve as the only means of transportation between the mine and the surface for salt, workers, supplies and fresh air. The No. 1 shaft measures 2.7 by 6.4 meters (9 x 21 feet) and extends from the surface to the No. 4 level at 588 meters (1,930 feet); this shaft still serves the mine as the production shaft and exhaust airway. The No. 3 shaft was sunk in 1976 and is the only shaft extending to the No. 6 level at a depth of 701 meters (2,300 feet). It is the deepest 3.7-meter (12-foot) diameter vertical hole ever bored. The shaft is concrete-lined and is used to transport workers and supplies as well as serve as a fresh airway. Instead of sinking the No. 1 shaft to the No. 6 level, two slopes were driven to connect the two levels. The slopes dip down at a 15-degree angle. One of the slopes is used for workers and equipment, and the other is where the final product is moved via conveyor to the No. 4 level, where salt is stored until it is ready to be hoisted to the surface.
Producing salt three shifts a day
The Cayuga mine operates three shifts per day, five to six days a week, with salt produced on all three shifts. Salt is mined from a series of faces, each 10 meters (32 feet) wide and 3 meters (10 feet) high.
The production cycle begins with “scaling” the newly created tunnel. A machine with an extendable boom scrapes the tunnel roof to dislodge loose slabs. After scaling, the roof above each face is bolted using a roof bolter to create safe working conditions for the miners. The next step is drilling the face, followed by undercutting, which provides a second free face into which the salt can break. During this process, machines cut a 15-centimeter-high (6-inch-high) slot into the face spanning its 9.8-meter (32-foot) width.
The next step in the cycle is pneumatically loading each drill hole with a blasting agent. Each hole is detonated with a non-electric blasting cap. Blasting occurs at the end of each shift to allow the fumes to clear before workers re-enter the faces. Finally the salt is removed from the faces with Cayuga mine’s fleet of Cat LHDs. These machines are low-profile front end loaders equipped with 9.5-cubic-meter (12.5-cubic-yard) buckets for mucking the faces. Loaders dump directly onto a feeder breaker, which acts as a primary crusher and feeds material directly onto the conveyor belt system. Salt goes directly to screeners, which sort and size material and remove dust. Salt is then conveyed to the shaft and is brought to the surface in 14.5-tonne (16-ton) increments. Some salt is loaded on gondola cars as bulk product, and each year 100,000 tons of the product is placed into 18-kilogram (40-pound) bags, palletized and shipped via truck.
Maintaining the machine fleet
The Cayuga mine’s maintenance shop is located underground, about 4 kilometers (2.5 miles) from where mining is under way. “Because it is difficult to transport equipment between surface and underground, it is necessary to have fully equipped shops with very extensive facilities capable of handling any problems involved in the operation,” says Cargill’s Frank Caswell, maintenance planner. “These facilities include stock rooms, machine shops, rebuild shops, electrical shops and a hydraulic shop.”
The Cayuga mine has a 35- to 40-person maintenance department and uses state-of-the-art technology to service and maintain its equipment fleet. In spite of these capabilities, the mine relies on dealer Milton Cat to handle planned maintenance on its fleet of R1700G LHDs. Headquartered near Boston, Massachusetts, USA, the dealership has a branch about 113 kilometers (70 miles) from the Cayuga mine in Binghamton, New York. Milton covers the northeast United States, including New York, Rhode Island, Maine, Massachusetts, Vermont and New Hampshire.
“Doing our own maintenance on these machines would not be a good use of our time and resources,” says Shawn Wilczynski, mine superintendent. Milton is able to offer ready parts availability, technical support and expertise, he says, “but the relationships we have with the dealership’s people are the most important element Milton Cat brings to the table.”
Cargill purchased four of the LHDs between 2001 and 2003 and a fifth in 2007. The machines have a modified cab structure that allows them to fit in the various roof heights of the salt seam. To get the LHDs into the mine, they had to be disassembled and cut in half. “After we took them apart, we photographed each piece, wrapped and crated it, then labeled it and pasted the photo on the box,” says Sebastian “Buster” Fiacco, Milton’s service manager. “Smaller pieces were individually wrapped and crated together, and we attached a catalog of photos to the outside of the crate.” These parts and pieces went down the shaft and were reassembled underground.
Each of the R1700s works about 3,000 hours per year. With 20,000 to 21,000 hours on each machine, even diligent planned maintenance wasn’t doing enough to deliver the availability and reliability Cargill needs to meet its production goals. “We needed to increase our productivity,” says Caswell. “We operate in five faces, and we always shoot for firing six rounds a day in order to meet production. If you have high downtime, you can’t meet that target.”
As machines exceed 20,000 hours, spikes in maintenance and repair costs are common, explains Fiacco. “The mine was beginning to have issues with component life and engine and transmission failures,” he says. “Their production people were complaining about downtime. Unscheduled repairs and failures were becoming more common and costs were out of sight. Our goal was to reduce these spikes and get maintenance and repair to be more level and predictable.”
Looking for a solution
As it became more apparent that the site must deal with its equipment issues, Milton presented a number of options:
- Purchase a new R1700G
- Perform a Certified Power Train rebuild
- Perform a Cat Certified Rebuild, rebuilding the entire machine except the frame and bucket and eliminating replacement of the lift arm
- Perform a complete CCR, rebuilding the entire machine and frame, sandblasting the bucket and installing a new lift arm
As Cargill went through the four options one by one, they addressed the drawbacks to each alternative. While purchasing a new R1700G would give the mine the availability and reliability it needed, the cost and a lead time of 14 to 16 months eliminated it as a viable solution. Performing a Certified Power Train rebuild would help improve performance and reliability, but wouldn’t eliminate the need for repairs to the machines’ other systems. A CCR without the frame, bucket and lift arm included also wouldn’t eliminate the need for continued downtime. The lift arm would require repairs annually, with associated downtime of at least a month.
Milton was convinced that the complete CCR was the best solution. “We had been trying for three years to get them to consider a CCR,” says Fiacco. “We told them, ‘To get the reliability you need at the cost you need, the CCR is the way to go.’”
A CCR is a complete rebuild process endorsed by Caterpillar, performed only by certified Cat dealers. Machines are rebuilt to like-new specifications, using only genuine Cat parts. Critical engineering updates are incorporated into the machines, and oftentimes they perform even better after the CCR than they did when they were new. Machines that have undergone a CCR are then issued a new serial number and warranty.
“We incorporate the very latest critical engineering updates into the machine at a fraction of the cost of buying new,” says Fiacco. “The CCR includes a thorough evaluation, including more than 350 tests and inspections, and the automatic replacement of approximately 7,000 parts.”
The rebuild can be performed by trained dealer service professionals only, and exclusive Original Equipment Parts are used. “Caterpillar sets the guidelines and we must follow their protocol,” says Fiacco. “Parts are non-negotiable. The inspection process and all other protocols are required.”
For Cargill’s fleet, the CCR proposal included a new heavy duty salt series lift arm, upgraded HID lighting and a Quick-EVAC system, which empties most diesel engine sumps in less than 60 seconds, enabling a thorough engine lube oil and filter change in less than 20 minutes.
Once Cargill agreed to do a CCR — starting with just one of the mine’s R1700s — they set a number of goals and challenged Milton meet them:
- Stay within budget — rebuilding the machine at a cost of around 60 percent of a new machine.
- Complete the rebuild in 12 weeks.
- Give Cargill better control of its maintenance and repair budget, allowing a flat budget for three years or 6,000 hours.
- Decrease equipment downtime and improve reliability.
Fiacco assured Cargill that the rebuild would bring the machine back to like-new condition for just over 60 percent of the cost of a new machine. The program also included a three-year, 6,000-hour warranty for non-wear failures — a request made by Cargill.
“We wanted to put an extended service protection on the powertrain and hydraulics for an additional three years or 6,000 hours,” says Caswell. “We didn’t purchase that when it was new. Having Milton take care of all major components and service would give us the flat budget we wanted.”
In addition to meeting these significant goals, Cargill gave Milton another challenge: Complete the rebuilds underground.
Milton has done several CCRs, but all were above ground and on various models of machines. “These R1700s were the first done in our company — and the first underground CCR in the world,” says Fiacco. “We had to develop a team to determine how to quote, execute and deliver the project. We had no historical data because a complete rebuild had never been performed underground before.”
Planning and evaluating
Milton performed a great deal of strategic planning and evaluation in preparation for the rebuild. They had to make a number of decisions, like which Milton technicians would perform the work, what their shifts would be, how the work would impact the mine operations, and which branch locations would be mobilized to perform rebuilds of the components after they were removed from the machine.
“Our planning process involved evaluating both the mine and the machine,” recalls Fiacco. “We talked about the disassembly, the component and rebuild strategy, reassembly and commissioning. We tried to think of every obstacle we would face and come up with solutions to overcome them and make this a streamlined process.”
A lot of time was spent evaluating the machines. “We had to make sure we knew everything we were going to do and/or need throughout the entire process,” says Fiacco. “You can’t forget a part and stay on target. A detailed system evaluation was performed by Cat technicians and product support sales representatives four to six weeks prior to the start of rebuild. Oil samples were taken from all compartments. These were beat-up machines. They do run into walls and scrape things. We knew we would need a person to do welding and boring, blasting and painting.”
Cargill representatives also participated heavily in the planning process. “We didn’t provide the people to get this done, but we did everything we could to help,” says Caswell.
One of the biggest considerations was the mine’s production schedule. “One of our objectives was to keep meeting our production targets,” says Caswell. “We worked together to figure out how to make the process efficient for Milton, but also to consider how the rebuild would disrupt our operations. For example, we had to plan times for Milton to use the shafts to bring parts and components into and out of the mine while considering our routine supply deliveries and mining cycles.”
Milton had to consider the impact the mine’s schedule would have on the rebuild process. “If we had something come into the site on a Monday, it may not make it down to the shop before Wednesday or Thursday,” says Fiacco. “We didn’t want to delay the mine’s production. But we also didn’t want our guys standing around waiting.”
The location of the maintenance shop — 4 kilometers (2.5 miles) away from the mine entrance — also had to be factored into the completion time. In addition, the shop’s capacity created some obstacles. Cargill designated a parts storage area for the rebuild, but due to restricted space in the underground shop, just-in-time parts delivery was critical.
Performing the CCR
Milton decided to have two technicians perform the bulk of the work and arranged for them to live in a nearby hotel so they would be as close as possible to the site. They were originally scheduled to work 8-hour shifts, but changed to 12-hour shifts in order to make the best use of time once they traveled to the workshop.
The first step was disassembly, stripping the machine of its components down to the bare frame. Components were carefully removed in the main shop and evaluated before being sent out for rebuilding. Frames and other structures were rebuilt in the underground shop.
“We relied on several Milton branches to get this work done,” says Fiacco. “We shipped components to different sites so we were rebuilding multiple components at the same time in different locations.”
A special custom paint area was created at the mine and components were blasted and painted there. All components were sprayed at the same time for a more professional appearance.
During reassembly, frame sections were moved back into the main shop, and wiring harnesses, hydraulic hoses and some power train components were reassembled. Technical updates and programming of components were performed, and then the frame sections were assembled. Technicians installed the cab, with new wiring harnesses and instrument panels; new axles and tires; and the Quick-EVAC system. The machines were then filled with all new fluids. Finally, new plaque cards were installed with new machine serial numbers.
When it was time for commissioning, the machine was started, allowed to warm, and fluids checked again. Engine, transmission and hydraulic temperatures and pressures were monitored and adjusted as necessary and the engine performance levels were checked. Then the machine was used for mucking prior to another check of pressure.
A CCR involves the replacement of about 7,000 parts — a logistical challenge given the fact that they were being replaced underground. “Normally, delivering parts to a customer is not a difficult task,” says Fiacco. “But when your customer is 701 meters (2,300 feet) below ground and miles from the elevator that delivers the parts, planning is a major concern.”
Milton’s parts and service departments worked hand-in-hand, and the parts department dedicated one parts counter specialist to the project. This specialist and the parts manager met with the technicians in the mine to establish best practices based on the work environment.
“For example, special packaging and parts coding procedures were implemented so the technician did not spend too much time looking for parts,” says Fiacco. “Just-in-time ordering and delivery was coordinated through the parts department so we did not have too many parts before they were needed.”
“I can’t stress enough how important it was to coordinate parts,” Fiacco continues. “We also had a staging area above ground to help streamline the process.”
Another key to the successful parts process was the Cat parts system. “There is no one better at delivering parts than Caterpillar,” says Fiacco. “Parts ordered today arrive the next day. We don’t know any other manufacturer who can offer that. And the correlation between parts and service was integral in ensuring we completed the job on time.”
Relying on good communication
Throughout the process, Milton and Cargill worked together to find ways to make the operation run more smoothly and to ensure success. Both agree that open communication was the key.
“Communication was huge,” says Fiacco. “We listened to our customer and they listened to us and together we were successful. Sometimes it was just little things, but when you add them up, they made a big difference.”
Fiacco shares an example of a solution developed by mine personnel to streamline the hose-replacement process during the rebuild: “Each machine requires a large number of hoses, and when they are packaged and placed in a box, the technician must sort through them to see which hose he needs at any given time. Cargill put up a line where the technician could hang the hoses, and he could immediately tell by length which one he needed.”
A Cargill technical coordinator also helped the technicians keep in contact with co-workers and vendors above ground. They had laptop computers and air cards for internet service, but they didn’t work underground. This made it difficult to order parts, a process that is done primarily online. The Cargill coordinator developed a solution that gave the technicians internet connectivity.
“We had total support within our company and at the mine, and that’s what made it work,” says Fiacco.
Celebrating a partnership
Two rebuilds have been completed to-date and a third is under way. Both Cargill and Milton representatives believe that their long-term relationship — a relationship that was further strengthened by this process — was a key to the successful CCR.
“This is a tremendous example of collaboration,” says Milton Cat’s Frank D'Ambrosio, regional service manager. “In adverse conditions, with commitment and good planning, we demonstrated our strong partnership. And the result was high availability and lower costs for our customer.”
D’Ambrosio says he would like what Milton and Cargill have accomplished to serve as an example for other dealers and customers. “We’d like to see other underground mines and their dealers do what we’ve done,” says D’Ambrosio. “It showcases the strength of the dealer-customer partnership. And it shows the strength of Cat products.”