NEW FRONT-END LOADER DRIVES PRODUCTION FROM THE QUARRY FACE TO THE PLANT.
By Mark Sprouls
Martin Stone Quarries Inc. got its start in 1953 when Henry Martin leased a rocky patch near Bechtelsville, Pa.
“My father, Henry Martin, started this company in 1953. When we started, we sold material by the truckload right out of the bank to farmers and township people,” said Tom Martin. “My dad, me and one other man were the whole crew. We used a ¾-yd. excavator to mine, and we produced about 75 tph.”
Now the third generation of Martins handles day-to-day operations at the quarry – situated in the same area as the original, leased property – and the mine produces 1.5 million tpy with a mobile equipment fleet that has little in common with that original excavator. Rather than breaking rock with a hammer as Tom did as a young man, the Martins use an automatically controlled 600-tph processing plant to prepare rock for sale.
The quarry has seen a steady progression from its humble beginnings more than 60 years ago when it started digging into the massive deposit of granite gneiss. The very hard, abrasive rock resists mining, but it yields quality aggregates. The work to build the business continues.
“The changes we made to the plant control system in 2006 were a major leap,” explained Travis Martin, operations manager and third-generation owner (Tom’s son). “The most recent high-impact capital expenditure is the purchase of a Cat 990K wheel loader. The 990K is sized to increase our input to the plant, and we want to give our crews good equipment to operate.”
A Single Loader
Before any of the rock loading machines go to work, Arnold Drilling bores 6-in.-diameter blastholes and Mauer & Scott Inc. does the loading and blasting work. The crew shoots once per week to yield 30,000 to 40,000 tons. The shots create well-fragmented rock as well as a relatively smooth highwall in the difficult rock. Bench heights are 50 ft.
Martin Stone relies on a single face loader for the vast majority of feed to the plant, so the role of the 990K is critical, as was its 990 Series II predecessor. The old 990, with about 50,000 hours on the meter, now serves as the backup face loader. Its longevity is owed not only to its design, but to the proper operation and maintenance performed by Martin Stone personnel and rebuilds performed by the local Cat Dealer, Giles & Ransome.
“Any machine can run well for 5,000 or 10,000 hours,” said Travis Martin. “But we’re looking for frame life of 40,000 to 50,000 hours. We want a machine that’s going to perform over its entire life. And we also need to know the service and support is there from our equipment dealer. We have confidence that Ransome will be there throughout the life of the machine.”
At Martin Stone, consideration for employees is truly a part of the new equipment purchase decision, as current managers carry on the vision of Henry Martin who laid the foundation for a family business in which employees would be treated with respect. “Martin Stone has about 50 employees,” Travis Martin explained. “We recognize how valuable our employees are, and we try to give them what they need to succeed. We like to give them great machines to work with.”
The 990K has one primary operator who does production loading during day shift, five days a week, and he is known for caring for the machine as if it was his own. “The 990K hydraulics and greater power make it easier to operate,” said Bill Hook, 990K operator. “It has much more hydraulic power. I can curl the bucket right into the face without having to use lift power. And the cab upgrades, like the air cooled seat, make it nicer to operate. The trainer seat is a good safety feature, too.”
Hook points out that the sharp, abrasive granite requires special considerations: “A big concern is keeping the floor clean – to keep the loader and truck tires from getting cut. Also, we use penetration tips on the loader bucket and replace them every 200 hours.”
The second-shift loader operator feeds the plant from stockpiles created near the hopper during the daytime production shift. As a result of operating 16 hours per day during the workweek, the 990K will accumulate about 3,000 operating hours this year. The number of operating hours magnifies the savings in fuel costs, when compared with the previous loader.
“The 990K fuel burn is about 20 percent less than the 990 Series II it replaced,” Travis Martin said. “We track that with VisionLink reports generated from Product Link data. Uptime is critical for that loader, so we also use that information for maintenance and repair planning.”
Cat Product Link is the onboard monitoring and wireless data transfer system that feeds VisionLink, the interface and software that enables customized reporting of machine health and utilization. The telematics system reports machine location, idle and operating time, fuel usage, fault codes and alerts, and information from the onboard payload system.
Fuel-efficiency gains stem from the design of the Cat C27 engine, which meets Tier 4 Final emissions regulations, and from the use of Economy Mode. Eco Mode uses on-demand throttle as the operator maintains normal operation while the 990K manages the engine speed. The result is reduced fuel consumption and comparable productivity.
Three 60-ton-payload trucks – a Cat 773F and 773E and an older Terex model – serve the face loader during the production shift. The 990K is a good three-pass match for the trucks. Currently, trucks haul about a half-mile up a 10 percent grade from the face to the hopper. The quick truck cycles and a 60-ton hopper feeding the 600-tph jaw crusher enable the trucks to build stockpiles for feeding the plant at night.
Payload monitoring on the loader helps optimize loading to get the most out of the trucks without shortening their service lives. Additionally, the payload statistics are used to verify the plant belt scale numbers – a bonus that came with the new 990K.
Two high-hour Cat 988B wheel loaders supplement the 990K as they move loose material when needed. A Cat 345C hydraulic excavator also works in and around the pit. It loads articulated trucks with soil and other overburden, and it sometimes blends material at the face.
Keeping Machines Running
“We take care of all preventive maintenance on the mining equipment, and Ransome Cat does major component repairs on Cat machines and warranty repairs on newer Cat machines,” said Gary Yoder, shop supervisor for Martin Stone. “We operate machines for several lives, so we need good support way past the standard warranty period. The Caterpillar reps in our area have been very good in supporting us.”
As an example of a second life for Cat machines, one of the quarry’s 988B wheel loaders underwent a Certified Rebuild by Giles & Ransome technicians a few years ago. The loader was rebuilt to new specifications – and it’s still working now.
Yoder oversees an eight-bay shop with one bay able to accommodate the largest of Martin Stone’s machines. Maintenance personnel hours are about equally split between maintaining mining machines and the highway trucks. Most of the highway trucks use Cat C15 engines, which are also supported by the Cat dealer
“We are authorized to do our own Peterbilt warranty work,” Yoder said. “That allows us to get a truck back into service quickly. Getting equipment out as fast as possible is our biggest challenge.”
Helping meet the challenge is a shop that is well supplied and updated with the tools needed to work on the latest machines. Also, the shop is as clean as the work will allow.
“Having a clean, well equipped shop makes it enjoyable to work here,” Yoder said. “I have been at Martin Stone for 26 years, and I can say that the Martin family is people oriented. They not only provide the space and tools you need, they treat you like you are part of the family.”
It seems that Henry Martin’s concept of a family business lives on more than 60 years after its beginnings.
Mark Sprouls is a mining writer based in Tucson, Ariz.
Martin Stone supplies a variety of products ranging in size from landscape rocks and R-4 riprap to manufactured sand. Nine different grades of crushed stone and five different modified stone products are the core. The commercial construction markets in New Jersey, Allentown, Pa., and metropolitan Philadelphia are major consumers. Martin’s biggest selling products are crushed stone #8 and #57 for asphalt and concrete mixes and various grades for road base.
“The challenge is making all of the different products to exacting specs and making sure that we have an adequate amount of high-demand products stockpiled,” said Travis Martin. “We recently had three major commercial projects start at about same time, and demand surged. Those are the types of situations we have to be able to handle.”
In addition to aggregates, the company supplies Martin Infield Mix for baseball and softball fields. The product is popular in the region and helps set the company apart from other aggregates suppliers.
A screening plant fed by a wheel loader processes loam that is blended with clay to make the standard mix. Custom Martin Infield Mix, a mix blended with sand, is available, too. Sales literature emphasizes that the infield mixes “… provide optimum drainage characteristics to enhance the playability of the infield.” The mix is popular for both newly created infields and for replenishing fields already in use.
Two Cat 980K wheel loaders do yard loading. Like the 990K, these relatively new loaders are prized by their operators, one of whom is 70 years old and still loves coming to work every day, according to Travis Martin. Payload scales on the loaders are used to optimize loading of highway trucks. The newest 980K has an integrated payload monitoring system from Caterpillar.
An automated loadout system is available at 4:00 a.m. and is open until 6:00 p.m. Opening the loadout early enables drivers who have long hauls on congested highways to beat the morning rush hour traffic. During regular day shift hours, a weighmaster operates the truck scale, and the automated loadout system continues to operate.
On a busy day, Martin Stone sees 500 highway trucks come to the loading yard, and as many as 750 have come through the gates. The yard loaders and automated loadout system stay busy. Martin Stone owns and operates 15 highway trucks. This fleet enables the company to better support customers’ needs.