by Kerry Clines, Senior Editor

Haverstraw Quarry is located on the Hudson River just north of New York City. The 157-acre quarry was originally owned by the New York Trap Rock Co., which opened the quarry in 1923. The quarry passed through the hands of a number of other owners before Tilcon New York bought it in 1981.

The main pit is located on the backside of a 525-foot mountain that faces the river. Though currently at an elevation of 100 feet below sea level, the pit was originally at an elevation of about 400 feet on the side of the mountain. At that time, haul trucks carried the rock from the pit, down the side of the mountain, to the road below for shipment. A special cable system was set up to allow a fully loaded haul truck traveling down the mountain to pull an empty haul truck up the mountain to the pit. “It was kind of like a trolley system,” says Lenny Tellone, a Tilcon employee and former plant manager at Haverstraw Quarry. “The quarry ran that way until about 1950.”

In 1988, a few years after purchasing the quarry, Tilcon began construction of a tunnel through the mountain, underneath the highway (9W) and the railroad tracks, to the river. Construction was completed in the spring of 1990, at which time the secondary plant was moved to the river side of the tunnel, as were the stockpiles and loadout area, making access to the river for barge transport much easier.

The primary crusher feeds material onto a conveyor belt that carries the aggregate through a 1,000-foot tunnel through the mountain, under the highway and railroad tracks, to the secondary plant near the river. The new Rockwell control system allows operators to make small adjustments to the crushers to maximize production of the plant’s biggest selling products.

“The tunnel is 1,000 feet long through the rock and about 21 feet in diameter with a concrete floor,” Tellone says. “A 56-inch conveyor goes through the tunnel along with power lines in the roof. We tied the conveyor into the primary and into the screen towers in the secondary. It cost a lot to do it, but it was the only way we could get to the river.”

A tunnel with conveyors and chutes runs beneath the stockpiles by the river, allowing specific materials to be sent to the dock for loading. “When things are busy, we load four or five barges a day — about 1,000 tons per barge,” says John Rufer, current plant manager at Haverstraw Quarry. “Right now, we’re a little bit slower. We’re loading two or three barges a day. We’re very conscious of not allowing anything to get into the river. We have to minimize the effect on our neighbors and the environment.”

Haverstraw Quarry has made an effort to minimize the amount of blasting at the quarry, as well, by making larger shots once or twice a week instead of smaller shots four times a week. “We spend a lot of money making sure the right controls are in place so we’re not affecting the neighbors too much,” Rufer says. “We have to in order to stay in business.”

Tilcon has an asphalt plant located on site that uses some of the material processed in the quarry, but a majority of the aggregate is shipped to New York City and Long Island for use in construction projects. About two-thirds of the material is shipped by truck and the rest by barge on the Hudson River. “We really want it the other way around, but that’s the way the sales are going this year,” Rufer says. “Barge transportation is a lot cheaper than trucking. It’s a competitive advantage for us.”

One interesting fact, according to Tellone, is that Haverstraw Quarry is the only quarry that dissects the Palisades formation — the five-sided columns of rock found in the area. “It’s a vertical column of rock that varies in width from 12 to 18 inches,” Tellone says. “If it gets bigger than that, it starts losing the formation. Geologists come to the quarry to study the rock formation.”

Optimizing the plant

During the winter months, the plant closes down and workers are laid off while winter maintenance is performed. The time is used for making changes that would normally cause a shutdown during the production season. This year, Haverstraw Quarry used the winter months to optimize its production system, replacing an outdated 1980’s control system with an updated Rockwell PLC-based process control system.

“Our biggest selling products here are our asphalt fractions — 1/4-, 3/8-, and 1/2-inch,” Rufer says, “and we can never make enough. We were trying to figure out how to maximize production of asphalt fractions with our regular crushing operation. That was one of our main objectives in upgrading control of the crushing process at Haverstraw.”

Alan Bessen, P.E., served as a consultant and project manager during the automation process. “When people in the aggregate business think of automation,” Bessen says, “they often think in terms of merely automating start/stop sequencing. In this case, we replaced an obsolete PLC and associated software with a new Rockwell control system configured to manage standard start/stop and equipment monitoring functions, including a new Rockwell PLC and an updated operator interface.”

Performance monitoring instrumentation was also added, including 15 belt scales that provide product yield data to the plant operator, enabling him to manage the yield of key products by making process adjustments in real-time. The new control interface will be automated in the second phase to use both current and historical data, enabling the computer to track, report, and adjust key process variables in real-time.

“I’m working on the advanced performance management stage with Sam Sawant, a crusher specialist with Innotech Solutions,” Bessen says. “Sam designed two of the key crushers in the system. We’ve been adjusting those crushers to optimize the yield of key products with great success, using the belt scale systems for feedback on both current yield and system capacity.” The feedback is presented to the operator, giving him the information he needs to make appropriate changes in feed rate, recrush setting, and crusher setting to improve performance.

“There’s nothing magic about automation in a quarry,” Bessen adds. “We take big rocks and make them into little rocks. Making the most money out of it in the process comes back to how you control the yield of products to get the most saleable product with the least by-products and waste. Improving profit is the reason for automating the performance management system.”

The plant processes the same amount of stone, but produces more saleable fractions instead of making larger stone that doesn’t have a market or has to go back for recrushing.

“Our crushers and scales are tied together so we can see what’s going on at any one time,” Rufer says. “We make product according to the program, not just according to what an operator decides to do. Instead of ending up with a bunch of material that we have trouble selling, we have the flexibility to make more of our hot products. The new system lets us make small adjustments to maximize production of the products we want to make. Before, we just crushed and got whatever came out.”

Before the new system was added, production of 3/8-inch product averaged 120 to 130 tons per hour. With the new system in place, the quarry hit a new record for 3/8-inch production in September of more than 250 tons per hour — essentially doubling prior production capabilities.

The new system allows employees to extract downtime, uptime, and what types of products are being made at any given time from anywhere. “We can see what’s going on, in real-time, no matter where we are,” Rufer says. “I can bring it up on my laptop at home. I can see how many tons of material are coming off any conveyor belt at any stage in the plant. I can check the production rate for the day and get a running graph of what products we’re making for the entire day.”

Phase II of the automation project, planned for this winter season, will tie up a few loose ends. “We’re seeing that we need to make a few changes,” Rufer says. “We want the crushers to interact with the new computer system, so the crushers can adjust on their own according to gradations that come off our belts at the time. I believe that will be the final touch to really take it to the next level, but you always want to stay one step ahead.”

Staying alive

Production levels at Haverstraw Quarry have been declining over the last several years. “Back in 2004, we produced about 2.8 million tons,” Rufer says. “This year, we’ll make about 1.35 million tons. This used to be a 24-hour operation — we ran three shifts and were off on Sundays only. Now, we’re running one production shift of eight to 12 hours and an eight-hour shift dedicated to maintenance. And we’re not working as many weekends. We’re still going, but we’re not going as much as we’d like to.”

In order to stay alive, the quarry has gone to a lean manufacturing concept. It currently has 38 hourly employees and six salaried employees — a drop from 93 employees back in 2005.

Each job is being closely scrutinized to see if there’s a better way of doing it. Employees are being cross-trained to make sure they can do many different jobs.

“When you look at the drop in demand, you have to look at ways to keep or increase your profits,” Rufer says. “It’s necessary. We’re kind of lean and mean now. We don’t have a lot of extra people around. With the cross-training and restructuring of all our jobs, we’ve become much more proficient.”

EQUIPMENT LINEUP

Caterpillar 992 wheel loaders (2)

Caterpillar 988 wheel loaders (3)

Caterpillar 980 wheel loader

Kawasaki Z 115 wheel loader

Hitachi 450 excavator

Hitachi 540 LR excavator

Komatsu HD605 haul trucks (4)

Caterpillar 773 50-ton haul truck

Terex T.A. 40-ton haul truck

Svedala 50-inch x 65-inch gyratory crusher

Svedala 84-inch STD cone crusher

Svedala 384AC crusher

Metso HP 300 crusher

Metso HP 500 crushers (2)

Sandvik H-4000 crusher

Sandvik H-3000 crushers (2)

Simplicity double-deck screen

Astec external RAP system

8 x 20 triple-deck screens (2)

8 x 24 triple-deck screens (10)

8,000-foot conveyor system

66-inch screws

Belt feeder

External hoppers

5-ton H&B batch plant

Hot bins (5)

Cold-feed bins (8)

250-ton silos (2)

Cooperating with the surrounding community and being good stewards of the environment has brought awards and accolades to Huntsville Quarry.

by Kerry Clines, Senior Editor

Every year during the National Stone, Sand and Gravel Association’s (NSSGA) annual convention, the association presents awards to aggregate operations that have gone the extra mile, whether improving relations with the surrounding community or reducing the size of the footprint left on the environment. In addition to these awards, the NSSGA presents operations that have won awards in two or more categories within a five-year period with a National Stars of Excellence award. The number of stars signifies the number of awards the operation received during the five-year period.

This year, Vulcan’s Huntsville Quarry became a two-star recipient. The quarry received the National Stars of Excellence award for having received the 2010 Environmental Excellence Gold Award, in addition to the 2008 Excellence in Community Relations Gold Award. This, in itself, is quite an accomplishment, but the awards didn’t stop there.

Being a good neighbor

Huntsville Quarry was opened by Madison Limestone Co. in the early 1950s and was bought by Vulcan Materials Co. in 1973. The stone processed at the quarry is a high-quality limestone and is primarily used in roadbuilding for asphalt, concrete, and base materials, as well as in residential and commercial construction.

The quarry is located within Huntsville city limits. Eli Christopher, area operations manager – North Alabama, Vulcan Materials Co., says, “We continue to be mindful of the appearance of our facilities and of the way we impact our community. There are some things that we won’t sacrifice, even in this down economy. Our position with the city has improved greatly in the last 15 years.”

Maintaining and improving the appearance of the entrance has helped the quarry continue its favorable relationship with the city. In fact, the quarry has been recognized by the city for its beautification and environmental improvement efforts. “For the last eight years in a row, the city of Huntsville’s Beautification Board has awarded our efforts with their annual beautification award,” Christopher says. “And, after having won this award for five consecutive years, they’ve now placed us on their ‘Honor Roll.’ We’ve also been awarded air pollution control achievement awards from the city for the last three years for various improvements we’ve made in our plant.”

Thinking of the environment

Huntsville Quarry participates in an air pollution control improvement program offered by the Department of Natural Resources (DNR) in the city of Huntsville. The DNR enforces the same air pollution control regulations as the Alabama Department of Environmental Management.

“They (DNR) visit and inspect our plant, annually,” Christopher says, “conducting dust emission readings along with visual inspections of our storm water treatment facilities.”

Four years ago, the director of DNR informed Christopher that the department had a program that could help tout the quarry’s air-pollution-control improvement efforts to the public. The program would explain what the quarry was doing now and what it could do in the future to control any air pollutants that might be produced at the facility.

Conveyors lead to and from one of the enclosed screening towers designed to reduce wind-blown dust and noise.

“We submitted our ideas to the Department of Natural Resources and said, ‘here’s what we’re doing,’” Christopher says. “We use an organic surfactant in our water truck for controlling the dust from truck traffic on our site. Instead of the typical water-only treatment, which can rapidly evaporate, the surfactant adheres to the ground so you don’t have to make as many trips in the water truck. We control the dust on the roads and reduce the number of hours on the water truck, so there’s less dust and less diesel exhaust.”

After seeing the results of the surfactant’s use on the quarry’s roads, a system was installed in the finishing plant area that adds an organic surfactant foaming agent to the water used in the plant’s dust suppression system to control dust emissions from the various plant processes. This system utilizes compressed air, water, and the surfactant to create a foam that adheres to the limestone and virtually eliminates dust emissions. Unlike water-only systems, the effects of the foam continue into the process, into the stockpiles, and help control dust generated by wind.

These improvements helped Huntsville Quarry earn air pollution control achievement awards from the city for the past three years. “It’s all about trying to improve air pollution control, and the city feels that our efforts deserve recognition,” Christopher says.

The quarry helps keep the environment clean by recirculating all the water that comes through the facility. “We’re very conscious of controlling any surface and process water that tries to leave our property,” Christopher says. “We capture it all in a settling pond system. The solids settle out, and then we pump the water back to the plant for use in dust control, to use in the water truck, and to wash the rock for concrete and asphalt use. It all recirculates. With the implementation of our water management program, the quarry has reduced its consumption of purchased water by over 40 million gallons per year. We have Rain Bird sprinklers along the plant entrance to water the grass and keep the asphalt pavement wet for traffic dust control.”

All screening towers in the finishing plant are enclosed. This, by design, helps reduce wind-blown dust and noise generated in the screening process.

Along with weekly sweeping of the paved areas of the facility, Huntsville Quarry has two wheel wash systems that help prevent tracking into the community.

The finishing plant’s dust suppression system uses compressed air, water, and an organic surfactant to create a foam spray that adheres to the limestone and virtually eliminates dust emissions.

The first system is located at the truck scales. An electronic eye is tripped by each truck as it approaches the scales. The sprayers activate and clean the wheels and the chassis. This helps prevent tracking onto the scales, as well as tracking out of the quarry.

A second wheel wash system is located at the front gate where it washes the tires of every vehicle that leaves the quarry. This system is quite different from the other. It doesn’t use as much water as the first, as the water is pumped up through pipes beneath the pavement rather than being sprayed. An electronic eye senses the approach of each vehicle and increases the flow of the water, so every vehicle leaves the quarry with clean tires.

Both wheel wash systems have drains that collect the used water to return it to the settling pond system, where it is recycled and reused.

Another environmentally friendly program the quarry participates in involves electricity usage. “Our electric power is supplied through distributors of the TVA (Tennessee Valley Authority),” Christopher says. “TVA has offered a seasonal time-of-use power rate. If we operate our facility during hours that are more friendly to their generation needs, the distributor offers us a lower cost rate.”

In the summer, those hours begin at 4:45 a.m. and end at 1 p.m. “If we go beyond 1 o’clock, our electricity becomes dramatically more expensive,” Christopher says. “TVA encourages people who can do it to consume the majority of their electricity in off-peak power times, due to seasonal generation issues. We’ve been participating in the cost-saving program for six years now. This effort speaks to the environmental issue of additional fossil fuel burn required to increase power generation in the Tennessee Valley.”

Even though the processing plant shuts down at 1 p.m. during the summer months, the scales stay open until 5 p.m, allowing customer trucks to haul all day. The quarry has seen as many as 55 to 60 trucks per hour cross the scales.

Involving the community

Huntsville Quarry takes advantage of every opportunity to communicate with and educate the community about the aggregate industry by inviting them out to the quarry, giving tours, and explaining what the quarry does. “One of the most popular events is our annual Open House,” Christopher says. “This year, we had almost 600 attendees. Lunch is catered for local leaders, neighbors, and customers to come and enjoy. This has been a great opportunity for us to inform our local leaders and community members about our industry.

“We also partner with our neighborhood elementary school,” Christopher adds. “Being actively involved with the school allows us to communicate with the students, teachers, and parents about earth sciences, as well as what our industry does and the methods used to minimize our impact on the environment. Our annual field trip to the quarry is always a big hit with the students and teachers alike.”

Huntsville Quarry also gains access to the community by being involved with area civic groups and county and city organized service groups. “We participate in a locally sponsored ‘Meals-on-Wheels’ program, helping deliver meals to the elderly and home bound in our community, and ‘Adopt-a-Mile’ as well,” Christopher says. “Our company website is also accessible to anyone with internet access. The website has been a wonderful tool to help inform the community about our accomplishments and the industry in general.”

“We’re a somewhat unique plant because of our location in the city,” says David Wheeler, assistant plant manager. “From the stripping walls up at the top, the quarry is about 500 to 550 feet deep. We’re mined out on one side of the pit, so we’re actually putting our spoil and waste rock back into the pit and filling it back in — reclaiming it.” The quarry has also been accepting an average of about 30,000 tons of ‘green concrete’ annually onto the property. This gives customers a place to put their concrete waste and keep it out of local landfills.

“We have an excellent crew at this plant with a lot of experience,” Wheeler says. “Some of these people have been here 40 years. One of our shipping loader operators has been loading on this yard for 35 years. He’s seen a lot of different equipment come and go — from a loader that didn’t have a cab on it to the one he’s got now. He’s also seen a lot of changes made in the way we run our business, and in the importance shown with respect to the neighborhoods we work and live in.” AM

EQUIPMENT LINEUP

Mobile Fleet

Caterpillar 992G wheel loader

Caterpillar 990 wheel loader

Caterpillar 775D truck (3)

Caterpillar 773B truck (3)

Caterpillar D8L Dozer

Caterpillar 980G wheel loader (2)

At the front gate, water bubbles up from pipes beneath the pavement to wash the tires of every vehicle leaving the quarry.

Caterpillar 980F wheel loader

Caterpillar 769C water truck

Ingersoll Rand T4 drill

Grove 522 crane

Caterpillar IT12 utility loader

Broce broom

John Deere 450 excavator with NGK G18 hydraulic rock breaker

Fixed Equipment

Metso C140 jaw crusher

Nordberg 7-foot cone crusher

Metso HP400 cone crusher

Nordberg 1560 Omni cone crusher

Metso HP300 cone crusher

Deister 60-inch x 28-foot vibrating grizzly feeder

Deister 6-foot x 16-foot triple-deck screen

Deister 8-foot x 20-foot triple-deck screen (4)

Deister 6-foot x 16-foot triple-deck screen (wash screen)

Deister 6-foot x 18-foot single-deck high-frequency screen

McLanahan double-shaft 36-inch x 24-foot fine material washer

By Kerry Clines, Senior Editor

Wisconsin-based Michels Materials uses nothing but portable plants and equipment at its Waterloo Quarry.

Wisconsin-based Michels Materials, a division of Michels Corp., does things a little bit differently at its quarries. Instead of hauling material from the quarry face to the primary plant, Michels moves  the primary plant to the quarry face. The company uses nothing but portable plants and equipment in its quarries.

The benefits of being portable

The benefits of using portable equipment are very apparent at Michels’ Waterloo Quarry near Waterloo, Wis. “Every piece of equipment in this quarry is portable,” says Maurice (Moe) Bohrer, sales manager for Michels Materials. Having portable plants gives Michels flexibility, not only in terms of individual sites, but also for crushing at other quarries. The company operates more than 100 aggregate operations throughout the state and the use of portable plants allows Michels to go into a specific location on a job-by-job basis. It can move the plants into the aggregate site closest to the project and crush just the amount of material needed for the project, which allows Michels to control its inventory.

Routine maintenance, such as relining cone crushers, is performed on a frequent basis because of the abrasiveness of the quartzite material being mined.

Haul trucks are no longer used at the quarry for production, they are only used when stripping. Portable plants allow the primary to be located close to the face, eliminating the need for haul trucks. “Once we set up our overland conveyor system, we did away with using haul trucks in production,” Bohrer explains. “The land conveyor carries the material to the secondary crushers and the finishing plant. That’s a real advantage because it eliminates not only the cost of maintenance, fuel, and a haul truck driver, but it provides for more consistent feed to the plant as well.”

Using portable equipment allows Michels to centralize maintenance for all of its quarries. “During the winter months, we move the equipment to our central headquarters in Brownsville, Wis.,” Bohrer says. “This allows us to go through each piece of equipment to make sure it’s ‘up to snuff’ before it goes back out in the spring. Because of our short production season here in Wisconsin, we don’t want to have a breakdown in the field. Doing all the maintenance in one central shop allows us to make sure the equipment is the best it can be when it arrives at the quarry to begin production.”

The material

Waterloo Quarry’s deposit is quartzite, which is a very hard material that can be rough on equipment. “Quartzite is a metamorphic rock, a hard stone,” Bohrer says. “It produces a very good finished product, but it’s tough on everything it touches, from when it’s being drilled, to when it’s sold as a finished product. Due to the abrasive nature of quartzite, drill bits wear down twice as fast as they do in a limestone quarry and crusher liners wear out four to five times faster. We use a very proactive approach with our onsite QC lab to run several gradation tests each day, while each product is being produced, to not only ensure that our products are meeting their required gradations, but also to monitor the wear on our crusher liners and screens, so we know when to change them before we produce an out-of-spec material.”

The overland conveyor system carries material up to the secondary crushers and the finishing plant where it is washed and stockpiled for loadout.

Three portable plants (crushing spreads) are currently operating at the Waterloo Quarry. However, there may be as many as five plants operating in the quarry at the same time, depending on production demands. Each plant is a separate entity with its own plant manager and production schedule. A fuel tank, generator, water truck, and tool trailer are standard issue for each crushing spread. The tool trailers store everything necessary for each plant to do the job.

“We don’t typically move the plants around inside Waterloo quarry during a season,” Bohrer says. “Our faces are so big and the deposit is so deep, we just set up the plant at the beginning of the season and that’s normally where it stays throughout the remainder of the year. The next spring, we may relocate it, but we typically try to position it in such a way that we don’t have to move it within the quarry. We’re not chasing the face, because we’re usually working two sides with big benches that will give us an adequate supply of feed material.”

Waterloo Quarry produces approximately 30 different products, but the four main products are dense base aggregate for highway and road construction, railroad ballast, asphalt chips for use in asphalt production, and rip-rap/armor stone.

“All railroads like hard rock for their track ballast and maintenance,” Bohrer says. “We have a distinct advantage being the closest hard rock quarry to the city of Chicago. We have access to all the Class 1 railroads, which tend to converge in Chicago, and all of the asphalt producers in Chicago as well. The armor stone, riprap that’s over a ton in size, is used by the U.S. Army Corps of Engineers for shoreline protection on Lake Michigan. We stockpile armor stone according to size, with some as large as 14 tons.”

At one plant, material is completely processed in the pit and put into stockpiles there. At a second primary, material is crushed and then transferred via a 1,500-foot overland conveyor system out of the pit to a secondary crushing/washing and finishing plant, where it is processed and then stockpiled.

Wheel loaders handle all the loadout at the quarry. Material gets loaded into customer trucks, as well as company trucks for Michels’ road construction division. Much of the railroad ballast is transferred to the company’s nearby rail siding for loadout into railcars for the 12 different railroads Michels supplies.

Waterloo Quarry produces about 800,000 tons of material per year. Most of the material is shipped by truck, with about 20 to 25 percent shipped by rail. “Our rail siding is about a mile south of the quarry,” Bohrer says. “Probably 98.5 percent of what we ship by rail is for railroad consumption — railroad ballast. We truck the material to our rail siding, push it up into piles on both sides of the tracks, and use wheel loaders to load the railcars. One track comes off of the mainline into the yard and then splits into two separate sidings. We can place up to 40 cars on each siding, thereby allowing all of the cars to be loaded without being moved or rearranged.”

The man and his company

Michels Materials has owned and operated the Waterloo Quarry since 1996. The quarry was originally owned by the E.E. Gillen Co., a marine contractor that opened the quarry in the late 1980s to produce armor stone for shoreline projects. When the Gillen Co. went through reorganization, Michels Corp. bought the quarry.

After Michels installed an overland conveyor at Waterloo Quarry, haul trucks were no longer needed to carry material out of the pit.

According to company employees, you can’t talk about Michels Materials or its parent company, Michels Corp., without talking about Dale Michels. He started Michels Corp. in 1959 with the help of his wife, Ruth, who started out driving one of the company’s dump trucks. Though the company began as a pipeline company, it quickly branched out into other fields, including aggregate production.

Wheel loaders handle all the loadout at the quarry, whether it’s a customer truck or a railcar.

“Dale Michels had a backhoe, some pick-up trucks, and a lot of guts,” Bohrer says. “He built this operation. For the people who worked for him, he was charismatic. He treated them good, compensated them well, and gave them great tools to work with, and, in return, they gave him everything they could. There are still folks here who were there when it all began and have stayed with the company these many years. Dale has since passed away, but his wife, Ruth, and their four sons still run the company today.”

EQUIPMENT LINEUP

First mobile crushing spread includes:

Baxter 42-inch x 50-inch primary

Nordberg HP500 cone crusher

Nordberg HP400 short head cone crusher

Cedarapids 6-foot x 20-foot wet screens (2)

Cedarapids 6-foot x 20-foot dual-finish screens

Superior 36-inch x 136-foot telescoping super-stacker

Kafka 48-inch overland conveyor (1,500 feet)

Multiple shorter conveyors

Kolberg 36-inch x 125-foot radial stackers

Atlas 24-inch x 80-foot radial stacker

Pioneer 30-inch x 40-foot radial stacker

Dandee 30-inch x 50-foot radial stacker

Nordberg 30-inch x 12-foot radial stacker

DRM 30-inch x 50-foot radial stacker

DRM 36-inch x 80-foot radial stacker

DRM 36-inch x 60-foot radial stacker

Homemade conveyors (7)

Cat 988H wheel loaders (2)

Second mobile crushing spread includes:

Nordberg C140 primary

Nordberg HP400 cone crusher

Sandvik H6800 cone crusher

JCI twin screening plant

Cedarapids twin finish screen

Superior 36-inch x 136-foot telescoping super-stacker

Johnson 24-inch x 40-foot conveyor

Atlas 24-inch x 70-foot conveyor (2)

DRM 30-inch x 35-foot conveyor (2)

DRM 30-inch x 50-foot conveyor (3)

DRM 36-inch x 40-foot conveyor

DRM 36-inch x 50-foot conveyor

DRM 36-inch x 70-foot conveyor

Homemade conveyors (3)

Cat 988H wheel loader

Cat 988G wheel loader

Load-out includes:

Cat 988G wheel loader (2)

Cat 988H wheel loader

Additional equipment:

Tamrock Panterra drill

Komatsu 55-ton haul truck

Cat 365 excavator

Mack 5,000-gallon water truck

International 5,000-gallon water truck

Case 1845C skid-steer loaders (2)

At least that’s where Teichert Aggregates hopes to find a way to lower energy costs at one of its plants.

By Kerry Clines, Senior Editor

California-based Teichert Aggregates began construction of its Vernalis Plant in 1999, completing it in 2000. “It was exciting,” says Paul Mercurio, production manager. “We started a new plant with new people. Fortunately, the economy was good at that time. We went up to double production shifts almost right away with the anticipation of growing the plant in the future. It worked out well.”

The new wind turbine towering over aggregate operations at Teichert’s Vernalis Plant is expected to supply 25 percent of the plant’s energy needs.

The Vernalis Plant replaced Teichert’s Tracy Plant located about 7 miles away, which was being depleted, and began supplying aggregate for the entire area. “Depending on the product, our sphere of influence could be as much as 60 to 80 miles,” says Jerry Hansen, plant manager.

“We go into the Bay area,” Mercurio adds. “Some products go as far as San Jose and some get into San Francisco, but it has to be a special product to get out that far. The majority of the products are centered in Stockton, Livermore, Modesto, Manteca, and all the surrounding area.”

Making adjustments

Since 2008, Teichert Aggregates, like every other aggregate operation in California and many aggregate operations nationwide, has been making adjustments to maintain business during the downturn in the economy. One such adjustment addressed not only lowering costs, but being environmentally friendly as well.

The plant was designed with distribution bins that allow material to be blended and sent in multiple directions.

“We had been talking about going forward, trying to figure out every way to keep our energy costs down,” Mercurio says. “We talked with Foundation Wind Power about the concept of installing a wind turbine on site. A group of investors put the money up for it, and we provided a site for them to place the turbine. We agreed to purchase the generated power favorable to our utility rate. The investors are responsible for everything else, including turbine maintenance.”

“The computer brain of the wind turbine is monitored in New York,” says Steve Grant, a former Vernalis Plant employee who now works for Foundation Wind Power. “Basically, electricity is generated at the top of the turbine and comes down cables. The blades turn, within reason, as fast as they can to generate as much power as they can. Another device senses what power is being sent and interacts with it to change it into 60 hertz, or 690 volts. That goes out to the transformer just outside the turbine where it is stepped up to plant voltage, which is 4,160 volts.”

There are sensors on top of the wind turbine that send wind speed and direction to the computer, which engages two yaw motors that turn the turbine into the wind. The pitch of the blades is adjustable as well. “The objective is to hold at a steady RPM,” Mercurio says. “They tune it to achieve that level.”

The wind turbine is expected to supply about 25 percent of the plant’s power needs, depending on wind speed and what’s running in the plant. “It’s an effort to have less of an impact [on the environment],” Mercurio says. “We have the land and the wind, and we consume the energy. The neat part is it’s locally provided energy. This is where you’re producing it, and this is where you’re using it.”

Twenty years is the average life span of this wind turbine. “By then, I’m sure there will be a better mousetrap, and we’ll probably want to replace it,” Mercurio says. “The challenging point is that it only produces energy when the wind blows, and usage depends on how much the plant is running. This is just dipping our toe in the water. We will see what it’s like and be sure it makes sense.”

Daily operations

The Vernalis Plant produces all sand and gravel. Larger stones are crushed, but there is no blasting. “We’re mining out of two different pits and blending the materials,” Hansen says. “We mine the pits and then fill them back in with the clay and silt that washes out of the material. The pit is composed of alternating layers of aggregates and clay, and we use scrapers to take the layers out in the reverse order they were put in. So we’re effectively harvesting — taking the good, relatively speaking.”

“That’s why we use scrapers,” Mercurio adds. “We skim horizontally to get the rock off, then remove the clay, then go back to the rock. You can’t be that selective with other types of equipment. We have self-elevating scrapers with paddle wheels, and they can take a relatively thin lift. The paddles rotate, pick up the material, and break up the clumps.”

The traffic patterns in the pits are all one way so the three or four scrapers that are usually working each day don’t cross paths, and the risk of a head-on collision is eliminated. The scrapers make the loop, then dump their loads into a grizzly feeder over an earthen hopper that feeds the material onto a conveyor belt, which carries it up to the processing plant.

Material goes through rotary scrubbers and vibrating screens. The three-eighths inch minus goes into a bucket wheel, which scoops it up and dewaters the material so it can be conveyed, then dumps onto a conveyor that carries the material to the concrete aggregate (CA) screens. “Bucket wheels are pretty uncommon,” Mercurio says. “You don’t see them around rock plants very often. You normally see a fine material washer.”

At the CA screens, the material is washed and sorted. “We make 1 by 4 pea gravel, bird’s eye, and concrete sand,” Hansen says. “The 1-inch plus goes out to feed our primary crusher. It then goes through a screen to get sized. The oversized goes back to our secondary crushers. The inch and a half goes to one stockpile, and the minus 1-inch goes to MA (mineral aggregate) screens where it is sized to make our three-quarter, half, three-eighths, and crusher dust.”

Tunnels beneath every stockpile contain a conveyor that transports the material to distribution bins. “The plant was originally designed with distribution bins because each one of the products can go so many different ways,” Mercurio says. “Underneath each of these distribution bins, there are feeders. You can run each one at a different rate to blend products. One belt returns material to the crusher if you want to recrush it, and another belt is a blending belt that goes out to the stacker where you can blend any proportion of any product that you want. Another belt goes to the asphalt plant so it doesn’t need a loader to feed it. We typically have two loaders servicing our customers.”

“The idea is not to touch the material again,” Hansen says. “We have the same thing on our concrete aggregate side where we wash it one more time before it goes up into silos to loadout into customer trucks.”

The plant is fully automated. Sensors detect when the level of material in a distribution bin or silo gets low and automatically turns on the conveyor to refill it. Even the asphalt plant will tell the feeder when it needs material and how fast to run.

Grant speaks fondly of his days with Teichert when the plant was being designed and built. “Teichert did it right,” he says. “All the conveyors have catwalks on them so it’s safer for a man to do repair work, such as changing a roller. Jerry [Hansen] could probably speak to the fact that the plant has a tremendous amount of flexibility and is extremely sophisticated. The plant is set up to blend product even when it’s not running. The plant’s rod mill is a piece of equipment that isn’t normally used in sand and gravel operations. It’s used more for mining and extracting ore. We bought it in northeastern Quebec, brought it here, and it’s being used to make sand.”

Hansen describes the rod mill as “a big cylinder similar to the super scrubber, only the inside is lined with cast liners and piled about waist deep with metal grinding rods that are 14 feet, 6 inches long and about 3½ inches in diameter when they’re new. The rods just lay inside the cylinder. We pump in water and aggregate and the cylinder spins. There are little lobes inside that lift the rods up, and then they roll back down. It gently grinds the rock into sand versus an impact crusher.”

“It’s more like what a river does,” Mercurio adds. “It grinds the rock on itself between the hard metal rods.”

Cost and community conscious

Teichert has adopted ways of being cost and community conscious at Vernalis Plant, as well as environmentally friendly. During the summer months, the plant operates in the mornings and ceases operation by noon. “From noon to 6 p.m., the peak time of power consumption on the grid, we take ourselves offline,” Hansen says. “Two reasons — it’s less expensive, and it leaves the power available for homes. It may not be as convenient for our guys as a traditional day shift, but they come in at 3:30 in the morning and are off by 11:30 a.m. or noon. They still have time to do other things, and it takes us offline during the peak. We do that every year — May through October.”

The repair shift comes on at 11:30 a.m. to get assignments for the day and handle repairs while the plant isn’t running. “That’s one thing we haven’t figured out,” Hansen says, “something that the rock doesn’t wear out. We just slow it with wear plates, rubber liners, urethane, and different alloys.”

EQUIPMENT LIST

McLanahan 8 x 25 super scrubbers (2)

SECO 6 x 14 single-deck inclined scalping screen

Simplicity 8 x 24 triple-deck inclined screens (5)

SECO 8 x 24 triple-deck inclined screens (3)

Svedala 5 x 14 single-deck horizontal screens (3)

Cedarapids 8 x 20 two-deck horizontal screen

Metso 6 x 10 single-deck dewatering screens (2)

Svedala 6 x 10 single-deck dewatering screen

Schenk 8 x 12 single-deck dewatering screens (2)

Metso HP500 cone crusher

Metso HP400 cone crusher

Metso HP300 cone crusher

Texas vertical shaft impact crusher

New Dominion rodmill-11 x 15.25

CFS density separator

Phoenix 80-foot clarifier

Weir slurry pumps (22)

Krebs cyclones (9)

Basic Technology FS400 bucket wheels (3)

Eagle Iron Works twin 44-inch coarse material washer

GreyStone twin 54-inch fine material washer

Kolberg twin 44-inch fine material washer

Trio single 44-inch fine material washer

Kolman 48-inch x 180-foot radial stacking conveyor

Plant conveyors (86)

Mobile Equipment

Caterpillar 633E elevating scrapers (5)

Caterpillar 633D elevating scrapers (2)

Caterpillar D10R dozer

Caterpillar D9R dozer

Caterpillar 14H motor grader

Caterpillar 623B water tanker

Komatsu WA600 wheel loaders (2)

Caterpillar 988F wheel loader

Komatsu WA500 wheel loader

John Deere 9320 tractor, w/18 cubic-yard scraper

Caterpillar 769C haul truck

Grove RT745 hydraulic crane

Kenworth 4,200-gallon water truck

John Deere 210 LE skip tractor

Caterpillar 246 skid steer

When West Hawaii Concrete was threatened with possible closure, a non-traditional revenue stream kept it open and in the black.

by Tina Grady Barbaccia, News/Digital Editor

When demand for construction materials slowed, West Hawaii Concrete was faced with shutting down one of its quarries. But that wouldn’t solve the operation’s woes. The site’s lease stipulated that minimum royalty payments would still need to be made, so the quarry not only wouldn’t bring in any revenue, but it would be operating in the red even after a shutdown.

The operation’s management team quickly brainstormed and came up with a non-conventional method of generating revenue: It established a green-waste disposal venture. This entrepreneurism not only saved the quarry and has kept it operating in the black, but it has filled a landscaping service need while diverting waste from the local landfill.

“This has enabled us to keep the quarry open,” explains Jason Macy, vice president of Kona, The Big Island, Hawaii-based West Hawaii Concrete (WHC), a subsidiary of Knife River Corp., part of MDU Resources Group. “At this particular operation, the volumes had fallen to a level where it wasn’t worth having the quarry open.”

How it all began

It all started when Puna Certified Nursery, a landscaping business, approached WHC about setting up a base operation in the quarry. The landscaper had been diverting all of its green waste to a landfill. “But then they approached us about composting their waste — grass, palm trees, palm fronds, and other green waste,” Macy says. It turned out that zoning allowed composting on the property, so West Hawaii applied for a waste/green waste permit, and a green waste disposal business was born.

Green waste that will soon be turned to mulch is dumped at West Hawaii Concrete in Waikoloa, The Big Island, Hawaii.

The permitting process took about six months to complete. Once the state of Hawaii granted WHC a permit, it began collecting material in the spring of 2009 and is able to take in 3,000 tons of green waste per year to be composted. The process takes about six months for full degradation of the material. However, the permit requires that once the material is composted and broken down, nothing may be taken off of the property that is more than 3/4 of an inch in size. “If you have a 3-foot tree trunk, then it reclassifies it [the permit],” Macy says. “They [the state] want it small enough so it’s biodegradable to make sure it’s not going to end up in someone’s yard as a waste product. There are a lot of restrictions on what we can and cannot do. We told our tenant that they could compost, but that they had to abide by the rules. We gave them the list of regulations they had to meet and are ensuring they are complying with the permit.”

Currently, WHC only allows Puna Certified Nursery to compost at WHC. “We haven’t opened it up to any other contractors,” Macy says. “Because we are limited to 3,000 tons of green waste per year, we didn’t have to limit Puna’s operations until we have a better idea of what we are bringing in, especially because this contractor is willing to do the composting itself.”

WHC currently charges $40 per ton to bring in Puna’s waste, but is considering giving the company a credit for what it brings in because it does do self composting. “If we were to expand and allow another contractor in at the same price, it wouldn’t be fair,” Macy points out. Currently, WHC has not processed any green waste; it has only taken it in.

To date, it has invoiced for about $72,000 since 2009.

How it all stacks up

West Hawaii Concrete’s Waikoloa quarry currently does not have any full-time employees. When the operation went inactive, the scale operator position was eliminated because it now can be accessed remotely from its other affiliated quarries. However, Macy says the operation still sells about 20,000 to 30,000 tons of material per year at the location and contract crushes about 250,000 tons per year. Overall aggregates operations — which include the Kona Quarry at 200,000 tons per year, Waimea Quarry at 100,000 tons per year, and the Waimea Cinder Pit at nearly 30,000 tons per year, equal nearly $8.5 million.

(Top) Fine white sand blankets segments of the operation at West Hawaii Concrete. (Bottom) Kemp Murakami, general manager for maintenance for Puna Certified Nursery, checks the temperature of a pile of mulch.

“We open [the Waikoloa Quarry] on an as-needed basis,” he says. “If rock sales justify opening it for a day, the location brings in a loader operator. We took a group of our tractor-trailer delivery guys and trained them on MSHA (the Mine Safety and Health Administration) Part 46 so they were certified to run loaders. If we need them, they load [the material] themselves, get scaled out, and make the delivery from there.”

Macy says WHC hopes to expand the green waste disposal system. “We didn’t get any opposition from the community, and we think it’s a good thing to be able to divert that trash from going into a landfill.”

The green waste comes from various sites at which the contractor, Puna, has worked. “It’s then brought to the Waikoloa site and ‘scaled‘’ — i.e. checked — to ensure there isn’t any outside rubbish in it. Anything contained in the waste must be green or wooded, Macy notes. Once the green waste has been analyzed and picked through, it is then stockpiled in windrows 4 feet wide by 12 feet high.

“You get green waste coming in every day and you begin making a windrow,” Macy says. “Every week, that windrow is turned so decomposition can start. Sprinklers are turned on to keep the waste wet.”

This decomposition process, however, comes with its own hurdles. “It’s challenging because we are in a very arid area, and the amount of water we have to use is substantial,” explains Geoy Purdy, aggregate division manager for WHC. “We found this out after we got into the green waste business.” Fortunately, Purdy says, no wastewater is created, so this potential environmental headache isn’t an issue. “You just sprinkle the water on light enough so it will help decompose the material,” he says. “This is why it’s so important to make sure there isn’t foreign trash in what’s coming in.”

Each month, a new windrow is created so 11 to 12 windrows are created through the year. Each row is more decomposed than the next. Wooded shrubbery is placed in its own windrow because it decomposes at a slower rate. After the wooded green waste decomposes, it is run through a grater or grizzly screen to remove larger material, returned to another windrow, and turned once per week.

“After we screen it, we take the final product and mix it with cinder and sell it as mineral-rich soil,” Macy explains.

Currently, Puna is using the soil for its own mulching needs, but Macy says WHC plans to blend it with WHC’s own soil and get a premium for the soil. At Aggregates Manager press time, Macy says plans were to begin selling the soil at a premium in about six months. “This would create yet a whole new revenue stream,” he says.

Reducing waste, building stewardship

Ned Pettit, corporate environmental manager with Knife River Corp., is “extremely pleased” with the WHC management team’s entrepreneurism. Pettit says the idea is not only innovative, but it also reinforces Knife River’s commitment to sustainability, environmental stewardship, and good corporate citizenship.

“It fits well not only with Knife River’s environmental commitment, but our quarry operation generates sales, and the project showcases our dedication to the local community,” Pettit says. “Giving back to the communities in which we operate is a core business commitment at Knife River.”

In a global economy challenged by evolving sustainability metrics, it’s essential to be proactive, Pettit says. This means asking the question, “How can we minimize our environmental footprint and remain a competitive supplier of top-quality construction materials?”

The WHC project addresses this question. “The composting initiative has reduced waste — we are diverting what would otherwise be a waste management issue,” Petit says. “It has freed up valuable landfill space and created an innovative product that holds both economic and environmental value for our communities.”

He adds that the WHC project “champions the notions of pollution prevention, waste minimization, material re-use and recycling, while producing an environmentally advantageous resource with benefits ranging from soil enrichment to site remediation. Compost is gaining such popularity that many state transportation agencies are now incorporating its use into their bid specifications.”

Staying in the green

Although still in its early stages, the composting program has been successful so far. And in keeping with green initiatives, Purdy and Macy have already begun working on their next green innovation. It won’t create a revenue stream, but it is in keeping with environmental stewardship and being a good neighbor.

The office trailer at the Waimea location has been converted to be 100-percent solar powered. “Because it’s a remote operation, we began operating off of a remote generator,” Macy explains. “Now, we keep the generator off all of the time and just operate off of solar power. We are looking at implementing this at all the other company operations.”

A Quick Look at Knife River

Knife River, a wholly owned subsidiary of MDU Resources Group and the parent company of West Hawaii Concrete, is one of the top 10 aggregate, ready-mix, and sand and gravel producers in the nation. It is the ninth-largest U.S. aggregate producer, ninth-largest U.S. ready-mix producer, and the sixth-largest sand and gravel producer. During peak construction season, the company employs more than 5,000 people. According to the company, “We are sitting on a foundation of more than 1.1 billion tons of aggregate and provide a wide variety of products and services necessary for building America’s infrastructure.”

Since purchasing the first aggregate company in 1992, Knife River says it has become one of the fastest-growing aggregate and construction companies in the central, southern, and western United States. The corporation has acquired nearly 70 companies located in 14 states and is licensed to perform work in many more. Its core business lines include aggregate, asphalt, ready-mix concrete, liquid asphalt, and cement.

A Look at West Hawaii Concrete’s Equipment:

Cedarapids 30×42 jaw crusher

JCI K300 cone crusher

JCI 5×16 triple-deck screen

Cedarapids 42×48 jaw crusher

Deister 8×20 Deister triple-deck screen

Cedarapids 8×20 triple-deck screens (2)

Canica 100s, D-10, and D-9 (2)

Caterpillar 988 loaders (2)

Caterpillar 980 loaders (5)

Caterpillar skid-steers (4)

Knife River Hawaii locations:

Aiea: Hawaiian Cement — Oahu Concrete and Aggregate Division

Kapolei: Hawaiian Cement — Cement Division

Kona: West Hawaii Concrete — Kona Office

Puunene: Hawaiian Cement — Maui Concrete and Aggregate Division

Waimea: West Hawaii Concrete — Waimea Office

A major dolomitic limestone operation creates new productivity for an old quarry and reduces energy costs at the same time.

By Carol Wasson

Several years ago, the Carmeuse Lime and Stone Quarry in Cedarville, Mich., hit a do-or-die point — “either rebuild its entire crushing facility or flounder,” says Ray LeClair, the site manager hired as the go-to guy to get a new plant up and running. The challenge was replacing equipment from the 1930s, which had been moved to the site in the 1950s, where it had operated with no upgrades other than maintenance for the next 50-plus years. Beyond that, the old primary crusher was located nearly a mile and a half from the quarry face, requiring three 150-ton trucks to haul material from the face to the primary feeder, then haul the crushed material to a secondary crusher near the edge of the quarry.

Current and future crushing capacity goals led to the selection of a robust jaw crusher at the primary. Able to process up to 1,600 tons per hour, the crushing circuit is unlikely to become a plant bottleneck.

“We had experienced numerous breakdowns with the operation of equipment that was just worn out,” LeClair says. “Upgrading was the right thing to do. We would reduce hauling, energy, and maintenance costs, all while increasing our productivity and profitability.”

Project planning began in 2007 with the major initiative being the design of a new two-stage crushing system in the pit, closer to the face. Crushed material would then travel on a newly installed 4,000-foot conveyor to an existing surge pile and rail load-out system. Material loads onto a private 14-car rail system to be transported 5 miles to an existing finishing plant and ship-loading facility where product is transported via freighter to numerous Great Lakes ports. More than 60 percent of the operation’s products supply the steel industry.

LeClair says that the project started out on the fast track and was scheduled to be online in July of 2008, but progress slowed and eventually came to a halt when then-owner Oglebay Norton sold the facility to Carmeuse North America. After some evaluation by the new owners, the project continued, and the new crushing facility was completed and started up in the spring of 2009.

Throughout changes in direction, design, and ownership, and into installation, startup, production, and current troubleshooting and diagnostics, one thing remained consistent — an atmosphere of close collaboration between LeClair and Telsmith, Inc., the company chosen to design and engineer the new crushing system and plant. According to LeClair, the manufacturer ultimately simplified a complex process by managing the project as a “singular source backed by a combination of resources.”

In-house design and engineering

After researching a number of plants and operations, LeClair says his manufacturer selection was based on its in-house design and engineering team. “From the very beginning, I worked closely with one engineer who was designated as the point person — although he did have the support of his entire staff,” he says. “We narrowed the focus to just two people — he and I. All questions would be funneled through us. This streamlined the project and made everything go very smoothly.”

The breadth and depth of Astec’s capabilities and resources eliminated confusion between different entities who might have otherwise designed various parts of the plant, he says. With the entire design under one roof, they were able to fast track the project and handle even the smallest details within the design upfront.

A modular plant concept

A modular plant concept was chosen for its two-stage crushing system. Modularity may shorten the time line for new plant development and streamline the installation process. Pre-designed modules are pre-assembled at the factory and ship in segments.

Automation allows the plant to be monitored remotely or through the control house.

LeClair says that, although modularity enabled the plant to be fast-tracked, he favors the design concept under any type of construction schedule. “No matter what the pace, I prefer the modular construction, as it creates a far better structure altogether,” he explains. “I like having these welded fabricated structures completed in a shop environment versus out in the field. You get the best penetration on the weld.”

Additionally, he explains that another incentive for the modular approach is the ability to economically relocate the primary circuit within the pit. “In about 15 years, we will move the modular primary to the face and convey to the surge pile of the secondary plant,” LeClair says.

When it came time to assemble the plant, the process was simple and straightforward. In addition to the plant and manufacturer teams, a contracting company — with no previous experience in erecting a plant — handled the assembly. Detailed drawings allowed the process to be handled seamlessly. “For the entire structure, we never had one anchor bolt out of place, which is remarkable in itself,” LeClair recalls.

Design goals

The top goals of the new crushing system design were locating both the primary and secondary circuits nearer to the face; meeting a minimum production throughput goal of 1,200 tons per hour; eliminating any bottlenecks throughout the crushing system; and minimizing fines production.

Due to the previous blasting pattern and the operation of the older gyratory crusher, the operation produced in excess of 300,000 tons of fines annually, which had no viable market at that time. Furthermore, the operator had no opportunity to remove excess fines until the material went through both processing operations and was put into the stockpiles. “So we had all the cost of processing the fines, and then had to recover them as well,” LeClair says. “Now we have the ability to remove the excess fines right at the quarry face with a two, triple-deck screen setup on the discharge side of the secondary circuit.”

The modular primary crushing station includes a 60-inch by 30-foot step-deck vibrating grizzly feeder; the largest jaw crusher currently available in the U.S. market; and a 175-ton live storage dump hopper. A 3,000-foot-pound breaker breaks up any large oversize before it hits the crusher.

The new plant has reduced monthly energy costs by more than $50,000.

“We could have gone with a smaller crusher, but to get the minimum of 1,200 tons per hour, we would have been at the top end of the capacity of that crusher — and we wanted room for growth,” LeClair says. “We would never want the first circuit, especially, to ever be a bottleneck.” He estimates that the unit can comfortably process up to 1,600 tons per hour. As such, the conveyors are sized to handle higher tonnage, and the screens are also sized for excess capacity with triple-deck versus double-deck models.

Material is conveyed from the jaw to the surge tunnel which features pan feeders to control the feed to the secondary circuit. “The tunnel was delivered to us in pre-assembled sections with lights, feeders, and conveyors actually hanging inside the tunnel. We could just lift it right off the trucks, set it on the concrete, and just bolt it up, establish all the connections, and never have to touch it again,” LeClair says. The surge feeds a modular scalping screen station with an 8-foot by 20-foot, triple-deck, inclined vibrating screen.

The modular secondary crushing station includes a 600-horsepower cone with an automated crusher control system. LeClair likes the anti-spin system on the cone, as it stops the head from spinning and reduces liner wear, while the automation program allows operators to monitor wear and allows adjustments on the fly. “We’re getting up to 1,300 tons per hour from the secondary, and that is exceeding goals,” he says.

As to the programming and PLC-controlled operation of the plant, LeClair says that the manufacturer assigned one of its in-house electrical engineers to interface with the Carmeuse electrical engineer. Either in the control house or remotely, LeClair can monitor and track every process at the facility, including transfer points, conveyors, motors, and sensors, as well as material flow and tons per hour. Diagnostics can be run on site, remotely, or by the manufacturer.

Meeting design goals resulted in significant operating cost reductions. In energy costs alone, LeClair estimates a savings of more than $50,000 monthly, in part due to the use of properly sized, high-efficiency motors throughout the plant. The operation also eliminated one 150-ton haul truck that burned more than 250 gallons of fuel in a single two-shift day and had an annual maintenance operating cost that averaged $25 per operating hour (not including labor costs).

LeClair says that Carmeuse is fortunate to have retained its seasoned employees throughout the recession, with nearly 60 being on staff today. “Through attrition, we lose some personnel, and with the new plant, we can operate without hiring replacements,” he says.

Finally, the new plant produces far less fines, and, fortunately, all current fines output is being sold to the steel market with no waste.

During its first year of seasonal operation (April to mid-November), the Cedarville plant produced nearly 2.4 million tons. “This year, we’re on pace to hit 3 million tons with the future growth capability of up to 5 million tons per year running at full capacity,” LeClair says. “That’s a great anniversary present for Carmeuse, which is celebrating its 150th year in business.” AM

Carol Wasson is an experienced writer in the construction materials market.

For Lafarge’s Calera Quarry, safety is more than a priority…it’s a way of life.

All aggregate operations must adhere to strict safety rules and regulations as set forth by the Mine Safety and Health Administration (MSHA), but Lafarge chooses to take safety one step further. The company expects its operations to not only meet MSHA rules and regulations, but exceed them.

On June 22, during its annual Safety Day, Calera Quarry in central Alabama became a member of an elite group of Lafarge operations. “Our annual Safety Day was especially important this year,” says Rory Smith, plant manager at Calera Quarry. “It was a celebration that our quarry was inducted into Lafarge’s Health & Safety Excellence Club. To become a member of that club, you have to meet very strict requirements. The lost-time incident frequency has to be zero. The total incident frequency rate has to be a very low number based on 1 million man hours. There are many business units in Lafarge, and to date, a very small percentage of those have achieved this award.”

Making it safe

“Our safety culture and safety philosophy can be summed up in a few words — take the time to do it right,” Smith says. He does it right and has a lot to be proud of at Calera Quarry — the operation has eight years without a lost-time accident and two years without a reportable injury.

“The crew is like a family,” Smith says. “We have a program we call the Green Hand/Gold Hand program. It’s not required that everyone participate, but we’ve had 100 percent participation at the quarry.”

Green Hands, the new hires, wear a green sticker on their hard hats; Gold Hands, individuals who have completed all their training and passed a probationary period of 18 months of employment without any reportable incidents, wear a gold sticker. “The idea is that Green Hands need a mentor they can go to when they have questions, concerns, or whatever,” Smith explains. “All they have to do is look for a gold sticker on a hard hat and they know that’s someone they can go to. This has been a good program for some time at Lafarge.”

In addition to reporting any accidents that occur, employees report all near misses as well. “If we witness anything that could have happened, or did happen but there was no property damage or personal injury, we especially want to know about these because they are freebies,” Smith says. “They’re lessons that we learn without having to pay a price. We don’t do this to lay blame or assess discipline, though. We share the information with other quarries within our company. It may save somebody else from incurring the same type of incident and maybe having to pay a price.”

Smith adds that permits are required for certain activities — working at heights, working in confined spaces, and hot work. Employees working at heights must be trained specifically for that, and must demonstrate knowledge of and competency in the wearing of fall protection equipment. Working in confined spaces and hot work often times requires an attendant and monitoring equipment.

“The permit process gives us, as management, an opportunity to ensure proper job hazard analyses are done and that the individuals performing the tasks have the proper training and knowledge of the materials that they are going to be using,” Smith adds.

Customer trucks are the wild card in the mix, according to Smith. “Customer trucks are why we’re here,” he says, “but truth be known, we don’t know a whole lot about those guys — what kind of training they may or may not have had; whether they are approved or authorized to be behind the wheel of the truck; what they may or may not be under the influence of that particular day. While they are subject to every rule or regulation of MSHA and every one of ours, they offer significant challenges. We have to witness them doing something before we can correct it, and sometimes that’s too late, so we treat those guys like rattlesnakes. If we want to enter an area where truck drivers are moving about, it’s incumbent upon us to make eye contact with them and confirm that they see us.”

Color coding helps create a safer environment. All company employees wear lime green safety vests, while visitors and contractors wear orange. This allows individuals to be identified from a distance.

Every vehicle under 1 ton in size is required to be equipped with a safety whip that extends approximately 8 feet above the ground, Smith says. This allows the vehicle to be seen when driving around high berms and stockpiles. Emergency flashers are also required when moving about the property.

Working areas in and around excavation are constantly inspected for falling or loose materials sloughing from the banks and walls, according to Smith. Stockpiles are kept pushed down from the top to avoid undercuts in the material.

“Our best safety tool against becoming involved with any kind of ground control issue is inspection and avoidance,” Smith says. “We back into parking spots so that we’re looking forward when we’re ready to leave. All our production equipment and yard loaders have CB radios, as do our control rooms, so that communication is not a problem. We employ bucket scales on all our end loaders, even the pit loader, to ensure that we don’t overload equipment. Our production equipment is also equipped with back-up cameras for additional safety.”

From the beginning

“Southern Ready Mix built this plant in approximately 1977 and began operating this crushing facility then,” Smith says. “The cement plant next door was seeking high-calcium limestone for the manufacture of cement and created quite a bit of spoil from those activities, which was a fantastic aggregate. So, this plant worked in conjunction with the cement plant crushing the muck that was otherwise unsuitable for cement production.”

Lafarge acquired the operation in roughly 2004, Smith says. The company acquired the cement plant as well, and both plants continued to work together just as they had in the beginning. Modifications and improvements to the cement plant have made it one of Lafarge’s premier cement plants in the United States.

“In some respects, it was an environmentally friendly, responsible endeavor because we were crushing the material that otherwise would have been discarded, thrown away, or backfilled,” Smith says. “We were actually using that material to supply local markets with excellent construction aggregate.”

That continued until about 2008, when Lafarge Cement and another construction materials company entered into an arrangement to do some mining together to secure reserves for both operations. “At that time, we began operating the quarry like any other operation,” Smith says. “We were actively mining, drilling, and blasting in one of the pits that had been in existence from the original cement company. Now we’re going after the reserves below the high calcium horizon left behind by the cement operation. It’s a significant change from having muck material brought right up to the crusher and dumped, to actively going out and drilling and blasting and hauling the material to a crusher just like in any other quarry.”

It takes teamwork

Calera Quarry has a small workforce of 13 employees ranging in age from 20 to nearly 60 years old, yet they manage to produce around 1 million tons of material per year, plus or minus. “I have a team member here who has 30 years of service at this property and another with 24 years of service,” he says. “I have several who have been here in the teens of years. But we do have some young guys that have filtered in as others retired or moved on.”

Almost everything at the plant, with the exception of the secondary crusher, the tertiary crusher and screen, and a belt or two is the same as it was in 1977 when the plant was built. It is still a manual plant, requiring an attendant at each stage of production.

The older equipment still performs well, and Smith credits this to the plant’s maintenance program. “We have a rigorous maintenance program that includes inspections, planning, performance, and follow through,” Smith says. “We do very specific inspections at specific intervals as determined by our maintenance program. From those inspections, we’ll plan ahead of time for what we need to do. Then, when we take the time to do those things, we do them efficiently. It’s a continuous cycle of pro-active maintenance activities. Obviously, things do still break, so we still have the reactive component in our maintenance program, and we always will, but we like to feel that the reactive component is much less than it would be without pro-active maintenance.”

Maintenance times depend on the seasons of the year. The quarry maintains a minimum inventory, so maintenance is matched with the production schedule, which is in tune with the demands of the marketplace. At times, this requires a split shift for the maintenance team.

“Our production people come in the morning and do pre-shift inspections, check their equipment, and we produce,” Smith says. “Then we do our post-inspection in the afternoon. The evening shift [maintenance team] knows what they have in front of them. They take care of the details, and we come in the next morning ready to go.”

Surviving the lean market

The Norfolk Southern Railroad has helped Calera Quarry maintain market share through the lean economy. “We have actually fared well because we have access to long-range markets through the rail,” Smith says. “We’ve been very fortunate. In fact, my team is still working five days a week in excess of 10 hours a day. Part of that is maintenance, but most of it is meeting production demands for our customer and contractor base.”

Calera Quarry owns the rail spur that comes onto its property. The Norfolk Southern Railroad pushes the cars in, then quarry employees take care of securing the cars for the customer, cleaning them, loading them, and getting them ready for shipment. About a quarter of what Calera Quarry produces goes out by rail, the rest is trucked out.

“We have a few specialty products that help us out with markets,” Smith says. “We produce rip rap, which allows us to penetrate some markets that others are not exploiting. Plus we have an ag-lime product that satisfies numerous state specifications to help with state and federal subsidies for the farmers. We produce from inch and a half, inch and 3/4, all the way to 3/8 minus screenings for asphalt companies, and serve several ready-mix companies, as well. We have Alabama DOT, Mississippi DOT, and Florida DOT-spec aggregate for road materials — concrete and asphalt.”

The quarry also penetrates the Florida market — primarily in the panhandle — with concrete and asphalt gradations. Lafarge Aggregates built a rail depot in Pensacola in 2007, so it could stockpile materials for its customers.

Smith says the company’s marketing team makes it a priority to achieve a balance in the materials produced at the plant. The team looks for sales of co-products — those products that are produced when making another product — to keep the operation in balance.

Production usually begins at 6 a.m, Smith says. “The scales open at 6 in the morning, and we’ll run till 4, 5, or 6 p.m., as product demands, Monday through Friday, and Saturdays as necessary. We use Saturdays, generally, for one-off projects; not maintenance and repair, but installation or improvement projects should we be making a process change that we know will make an improvement in the operation. We’ve been able to secure and meet demands of our marketplace within that structure for the last couple years.

“We’re still at pretty good levels here in a lean economy in 2010,” Smith adds. “We’re proud that we can offer value to what work is going on and that they choose us. We’ve seen a slowdown in road work but, recently, we’ve seen an increase in other building locally. We’re very fortunate to have a loyal contractor base. We pride ourselves as a company and an organization in providing not only quality materials, but quality support in all endeavors, including our business relationships. I think that is what’s responsible for the reputation Lafarge has in the industry.” AM

Vulcan’s Kennesaw Quarry is well known for the granite aggregate it produces, but is probably best known for its education program.

When Kennesaw Quarry began mining granite in the early 1950s, that area of northwestern Georgia was fairly empty, nothing like the suburban-Atlanta neighborhood that now surrounds the facility. Mining was easier when there was little development and few neighbors. But the area would find itself transformed from agriculture to a bedroom community for growing Atlanta and then a center for commercial, residential, and institutional development. Kennesaw Quarry supplied materials for much of that growth — the portion of Interstate 75 that runs through the area; Cobb County’s general aviation airport that was built in the 1960s on a portion of the property owned by the quarry; and Kennesaw State College (now University), which was founded in 1966; not to mention Town Center Mall, Cobb Place Shopping Mall, and a shopping strip along one of Cobb County’s busiest roadways. Over time, as more people began living and working in the area, Vulcan lost its anonymity. As civilization surrounded Kennesaw Quarry, mining became more complicated, but what might seem like a curse is actually a blessing.

Education is the key

Vulcan knew that the key to addressing concerns from the encroaching community was to educate the public about the operation and the importance of mining. It wasn’t enough for the quarry just to be involved in the community, the community needed to know why the quarry was there and what was going on inside the pit. So Kennesaw began an aggressive community relations program.

“Our community relations program began in the 1980s when Vulcan decided to relocate the county road that ran through the middle of the plant area to the edge of the property,” says Steve Collier, plant manager. “This allowed Kennesaw Quarry to begin work on the National Stone, Sand & Gravel Association’s ‘About Face Program,’ which led to the quarry’s designation as Showplace and, ultimately, Quarry of the Year’ in 1997. Once we felt a little better about our appearance and our operation, we began hosting tours of our facility.”

Enter Edith Parivechio, community relations coordinator. When Vulcan built a new employee training facility at the quarry, she recognized a greater potential. “It started out as an employee building, but it evolved,” Parivechio says. “After we built the building, we began putting granite samples in display cases. Granite samples are nice, but I thought it would be even better to display other minerals and objects as well. We have a great collection of fossils and minerals, and exhibits showing the importance of mining to our society.”

The building quickly became a museum and a place to educate school children, the community, and more. “There are three elementary schools nearby, and they did maybe five or six tours a year,” Parivechio says. “If they had a teacher who enjoyed teaching earth science or geology, they’d bring their students over for a tour.”

The new employee training facility quickly became a museum and a classroom for educating school children and the community.

But even with the quarry’s meeting room and museum, there just weren’t that many students coming to the quarry because it wasn’t well known — until the Wienman Museum (now TELLUS Northwest Georgia Science Center) brought some teachers to the quarry as part of a workshop. “The Weinman hosted a week-long workshop for North Georgia earth science teachers, and one full day was spent at Kennesaw Quarry,” Parivechio says. “There were 33 teachers in that group. Those teachers went back to different parts of the state, and people learned about us by word of mouth. The following year, I had 10,000 students visit the quarry. I never had to pick up the phone or advertise.”

When the children from local schools started visiting the museum and attending the education sessions, parents would sometimes come along. Before long, Vulcan was able to get the aggregate story out to just about everyone in the community. But it didn’t stop at the elementary, middle, or high school level. “We’ve always had local college groups come, but last year we had college students and their teachers visit from five states,” Parivechio says, “and we also had industry groups visit from three different countries.”

Parivechio conducts the tours, with logistical help from the plant employees and safety department. Safety is paramount and a safety briefing and review of the rules of conduct while on the property are always the first order of business. “We are advocates for our business and industry, but it is important that we incorporate information from the schools’ earth science curriculum,” Parivechio says. Students are shown different kinds of aggregate and videos depicting the production process and how the products are used.

“We try to keep the message entertaining, as well, by showing them the ‘Rockman’ video,” she adds, referring to the video set to the tune of “YMCA” which describes the production of and uses for aggregate.

“We cover a little bit of everything — just enough to make it exciting,” Parivechio says. “This may be the only time a student comes into a rock quarry, and I want it to be a positive experience. That’s why the teachers keep coming back every year. We give them a little bit of knowledge and a whole lot of fun.”

Vulcan built an overlook area large enough for a class to view the entire pit from ground level. Visitors are able to see the entire pit in action and understand every aspect of the quarry.

This past year, Vulcan put together rock boxes for teachers to take back to their classrooms. The boxes contain 10 rock samples from across the state of Georgia. Each rock is labeled, so that the aggregate learning experience can follow the children back to their schools.

In addition to school children, Kennesaw Quarry’s education program welcomes scout troops, senior citizen groups, church groups, and neighborhood groups. The quarry provides each group with educational materials, study books, worksheets, and Web links to enhance the learning experience.

The new employee training facility quickly became a museum and a classroom for educating school children and the community.

Kennesaw Quarry’s location near the TELLUS Northwest Georgia Science Center, in nearby Cartersville, and the Southern Museum of Civil War and Locomotive History, located in the City of Kennesaw, means that many school children will visit the quarry either before or after visiting one of the other museums. “We have very close ties with these museums, and Vulcan is a financial supporter of both,” Parivechio says.

Kennesaw Quarry’s community involvement has not gone unnoticed. “We’ve been nominated for the Kennesaw Business of the Year award,” Collier says, “and we’re working to get the Cobb County Business of the Year award, too.”

Daily operations

Kennesaw Quarry built a new processing plant three years ago at a cost of $28 million. The entire plant is now automated, so one employee in the control tower can operate everything in the processing plant. The new plant has a lot more bells and whistles than the old one and will run more tons per hour, but Collier says the real reason for installing the new plant was to uncover reserves that were located under the old plant. That’s where the mining is being done today.

Material from the pit is dumped into the primary crushing plant where it is reduced to 8 to 10 inches in size by a large Allis Chambers gyratory crusher.

“We have to take off 150 feet of overburden to get down to the good rock,” Collier says. “We’re going to take the level all the way down to 625 feet. We’re uncovering a lot of reserves.” The overburden is then dumped back into the far end of the pit for use in reclamation.

“We shoot, on average, once a week now, due to the downturn in the economy,” Collier says. “At one time, we were shooting every day or every other day.”

After the blast, aggregate is taken to the large, primary, 54-74 gyratory crusher. Large chunks of rock go in, and rock 8 to 10 inches in size comes out. A conveyor carries the crushed rock from the primary crusher to a large surge pile on the opposite side of the pit. From there, the material goes through a secondary cone crusher, and then a tertiary and quaternary crusher, as needed.

“The secondary crusher is a blue 8800 cone crusher — a high-speed crusher,” Collier says. “The one behind that is a 7-foot shorthead crusher. Once material is crushed at the secondary crusher, anything that doesn’t screen out that’s above 2 1/2 inches will go onto the belt and come back to the crusher again to be crushed even smaller.”

Once the material has been processed through the crushers and screens, it is placed in various stockpiles to await loadout. “Concrete companies want 57s and 56s to be clean,” Collier says, “so we wash them. We wash the fines out and pump them down into the bottom of the pit, which acts as our settling pond. The fines settle out on their own, so we don’t have to maintain a settling pond, which requires a couple of operators and extra equipment. We use the clean water for dust suppression in the plant.”

Kennesaw Quarry’s target market is within about 20 miles, so trucking is the transportation of choice. “We have a few customers that travel farther,” Collier says, “but the rule of thumb is we reach about 20 miles out…” Customer loadout is handled in a couple of different ways, however. A large, multi-silo tower allows truckers to drive under the desired feeder and load their trucks by pulling on a rope, but most customers prefer to drive into the plant to be loaded by a wheel loader.

“The loading is a little more accurate with the loader; the trucks don’t get overloaded or underloaded,” Collier says. “We’ve got scales on the loaders, so they can get the exact percentage that they need. We usually run three 980 loaders on the yard to keep our customers loaded. I’d say 90 percent of our customers are repeat customers, so they know right where to go to get their product and how to set up for the loader.”

Rail transport was once used at Kennesaw Quarry, but when the old plant was torn down three years ago, the rail went with it. Collier says there are times when he’d like to have it back.

The quarry’s top selling product is crusher run, which is used in highway construction. It accounts for probably 40 percent of all sales, so it is stockpiled in several locations in the plant for easy access. The second most popular product is 57s used for concrete. Two concrete companies border Kennesaw Quarry, which is very convenient for all concerned parties.

The quality control lab is essential to the operation and is consistently busy. A sample of crusher run must be taken every 1,500 tons to be tested and checked for gradation and quality. It has to meet Georgia Department of Transportation specifications. Concrete stone is sampled more often — every 500 tons. Automatic sweeps make it easier to remove the desired product from the belt for testing in the lab.

“Three years ago, we were producing 4 1/2 million tons per year,” Collier says. “This year, we expect to do a million and a half because of the downturn in the economy.”

The new plant will help Kennesaw Quarry be prepared for the economic upturn and increase in aggregate demand when it comes, which it surely will. Until then, like other aggregate producers, Vulcan will keep hoping for a quick return to better economic times. AM

EQUIPMENT LINEUP

Mobile Equipment

Atlas Copco DM30 blasthole drill

International grease truck

Rocktec Terminator RX 500 impact hammer

Cummins generator

Ford F-700 truck

Ford F-800 truck

International boom truck

Caterpillar 769C water truck

Komatsu 325 dump truck

Sterling SC800 truck

Komatsu PC-400 LC7 excavator

Ford F-750 truck

Genie manlift

Caterpillar 14G motor grader

Komatsu 210 excavator

Caterpillar 777D dump trucks (4)

Komatsu 785 dump trucks (2)

Komatsu 465 dump truck

P&H 75-ton hydraulic crane

Northwest 80D crane crawler/dragline

Caterpillar 980G wheel loaders (4)

Komatsu PC-400 LC6 excavator

Komatsu D-155AX-5 dozer

Caterpillar 992G wheel loaders (2)

Caterpillar 420D backhoe loader

Caterpillar 980H wheel loader

Processing Equipment

Allis Chambers 54-74 gyratory crusher

Sandvik H8800 crusher

Helser 7-foot short head tertiary crusher

5½-foot short head quaternary crusher

Deister 8×20 triple-deck screen

Deister 8×20 double-deck screen

Deister 8×24 triple-deck screens (4)

Deister 8×20 triple-deck wash screen

Deister 8×20 double-deck wash screen

NPK Hammer GH10 rock breaker

FMC Corp. feeders (4)

Linatex feed system

Conveyors (26)

Feeders (11)

Magnets (4)

Metal detectors (4)

Rip-rap sidekick

Flume

Separator

CalPortland’s Washington-based DuPont Pit delivers high-quality gravel to ports as far away as Alaska.

By Kerry Clines, Senior Editor

CalPortland’s DuPont Pit, located near the small town of DuPont, Wash., was ranked number 2 in sand and gravel production in 2009. What makes DuPont Pit successful? Actually, there are several keys to its success, including a unique deposit of material, a great location, and dedicated employees.

The deposit

DuPont Pit sits on top of what CalPortland claims is some of the highest quality gravel in the world. “This is a really unique deposit,” says Jim Tweedy, plant superintendent at DuPont Pit. “The material was deposited here during the last Ice Age, which most geologists say was around 14,000 years ago. This was the recessional outwash — in other words, this material was carved from the mountains by glaciers as they advanced from Canada into the Puget Sound area and was deposited by water flowing from glaciers as they melted. The material, ground and sorted by the glaciers and washed by the glacial melt-water, comprises a world-class deposit of sand and gravel.”

Material 1½ inch and finer goes through the wash plant.

The deposit is split into two veins. DuPont Pit sits atop one vein, and Steilacoom Mine, which was located several miles further north on the coast of Puget Sound until it closed in 2002, sat atop the other. Both mines shared the same basic deposit, but Steilacoom Mine, which had been in operation since the late 1800s, was renowned for its fine sand, while the DuPont material is a coarser deposit.

“Steilacoom was rich with fine, very clean sand, but we have a deficit of fine sand at DuPont,” says Scott Nicholson, director of aggregates, Materials Group, Northwest Division of CalPortland. “At the time we moved from the Steilacoom deposit, we applied for permits to reactivate the existing dock at our mine on Maury Island in Puget Sound. This mine is rich with fine sand and, if made available to the market, would balance the DuPont deposit well. Despite the fact that the Maury Island site is an existing mine and designated under local land use codes as a mineral resource of long-term significance, permit issues have held up construction of the dock and access to the sand for over 12 years.

“During this time, we have looked for alternative sources of sand to balance DuPont, including an extensive study on crushing the DuPont gravel to make sand,” Nicholson adds. “As part of the study, a test was used to compare the crushability of the DuPont material on a crushability index. We sent 50,000 pounds of gravel to Metso’s test center in Milwaukee. They told us if you score in the high teens, you have a very hard gravel. They did 10 tests on our gravel that averaged a score of 30. They said it was the hardest gravel that had ever come through their test center.”

The hardness of the gravel may not allow DuPont Pit to manufacture fine sand, but it does make the gravel highly desirable for projects that require high-strength durable aggregates. For example, in Alaska, where studded tires tear up the roads every winter, they use a test called the Nordic Abrasion Test to determine whether aggregates will resist studded tire wear. There are very few mine sites that can supply material that scores high enough on the test to supply material for surfacing major roadways in Alaska.

The location

DuPont Pit is located on the shore of Puget Sound, which provides a type of transportation that most aggregate plants don’t have — marine transportation. “About 80 percent of our material goes out by barge,” Nicholson says.

About 98 percent of the material produced by the plant is used within the Puget Sound Region including Seattle, Tacoma, and Everett. The remaining 2 percent is used for special projects in other areas like Alaska. “A typical barge transports about as much material as 186 truck and trailer loads, reducing traffic congestion and the overall carbon footprint, and it is safe,” Nicholson says. “Ready-mix and asphalt producers in the greater Puget Sound Region depend on DuPont to supply their aggregates. Of the four ready-mix companies in the Seattle area, including us, only one doesn’t use DuPont aggregate.”

It wasn’t all roses to get DuPont Pit approved, however. The permitting process took 10 years.

“We were very forthcoming about everything with the community — what we’re going to do and how we’re going to do it,” Nicholson says. “We have 114 special conditions that were set forth during permitting. One of the requirements is that we can’t disturb the bluffs along Puget Sound. So, from the Sound, the only thing you see is a cut in the bluff. We have a large tube that comes down to the dock with a conveyor in it, but our mining area can’t be seen.”

Another requirement was that DuPont had to have regular biannual monitoring of noise at the loading dock. People living on Anderson Island, just across Puget Sound from the dock, were very concerned about the level of noise that would be generated during the loading of barges. The regulation only allows the noise level on the shores of Anderson Island to be 5 dB above ambient. A third party chooses the time to test the noise levels and doesn’t notify the plant until after the test has been completed. They then ask what the plant was doing at the time of the test.

“Of course, it’s always the same,” Nicholson says. “There’s virtually no impact, no noise from our dock. One day, I got a call from someone who had been one of our biggest opponents during the permitting process. He said, ‘I just want you to know that I was wrong. I can’t hear anything and, in fact, I really enjoy watching the marine traffic.’”

In addition to Mine Safety and Health Administration noise standards, CalPortland has a very strict company hearing-protection policy. “Basically, the rule of thumb is, if you can’t have a normal conversation with someone, you’re required to wear hearing protection,” Nicholson adds. “We’ve got just a couple of places that we don’t require hearing protection, and one of them is the dock. There’s really no noise.”

DuPont Pit has been reaching out to educate the community and to, hopefully, improve people’s opinions of the aggregate business. “Recently, we’ve been doing a lot of field trips with grade schools,” Tweedy says. “They have a required curriculum where they have to study rock and minerals. So, at the end of the terms, the classes come out. We talk about concrete and the different things we make out of our materials, and where they see and use it in their daily lives. It’s a lot of fun.”

Daily operations

“In 1997, when the plant was built, it was probably one of the most automated plants in the country,” Nicholson says. “Of course, it’s not that now, but it’s still pretty impressive.” Many improvements have been made since then.

The first conveyor on the journey to the loading dock on Puget Sound is covered to protect aggregate material from the weather.

The whole system is designed around 2,400-ton-per-hour production out of the mine, while shipping is typically about 2,000 tons per hour. The material is mined in a simple scoop and dump fashion. A dozer maintains a workable slope in the mine to ensure safe working conditions for the loader operators. Two wheel loaders scoop up the sand and gravel and dump it into a feeder over a conveyor system that carries the material up to a fractionated processing plant. No processing is done in the mine itself.

“We bring it in to the primary screening plant and sort it off into three raw surge piles, two different sizes for the crushers and one for the wash plant,” Tweedy says. “We wash everything 1½ inch and finer through the wash plant. Out of the wash plant, we make four different sizes of washed gravel and one size of coarse sand. All the fines are pumped over to our sand house where we have four classifiers that sort off three more sizes of fine sand. On the crushed side, we feed the crushers from the surge piles. The material comes through the crushed/screening house, where we make four sizes of crushed gravel. Out of those 12 basic sizes of materials, there are few limitations on how many different blends we can make.”

The plant is designed with two parallel 1,500-foot-long tunnels running under the stockpiles. The stockpiles on one side are all washed sand and gravel and the other side contains crushed gravel. The processing plant runs right between the two rows of stockpiled materials, which helps contain the noise inside the processing plant. Quality control (QC) monitors material gradations in the stockpiles continuously to ensure consistency.

Two feeders under each product stockpile enable the plant to produce different blends. “When a customer wants a certain product, our QC lab analyzes what the customer wants in their specifications and selects, proportionately, the blend he needs to pull to make those specifications,” Tweedy says. “Then he designates that blend a product number and it goes into the data base. When an order is entered in the system, the product number dictates which feeders are activated to make that blend and ensures they are the only feeders that will open. It’s timed so that, no matter where you’re pulling from, when the material hits the shipping belts, all of it is perfectly blended. We currently run about 350 different blends on our data base.”

While barging is the primary method of transport for DuPont’s material, trucks transport the remaining 20 percent. The plant simply flips a gate to change loading from the shipping dock to the truck lines, and vice versa.

A series of two conveyor belt systems carries material to the loadout dock on Puget Sound. The first conveyor in the journey is covered. “Once the material is on the loadout conveyor belt, the only place for it to go is on the barge,” Nicholson says. “It’s about a 3,100-foot conveyor and is covered for two reasons. The primary reason is that we can’t discharge a drop of anything into Puget Sound. The Sound is downhill, so if it rained on the conveyor, it would discharge material into the water. The other reason is that this is a long, flat conveyor. If the power went out during a storm and the belt sat in the rain with material on it, it would get pretty sloppy.”

The second conveyor goes down the bluff to the dock on Puget Sound at an extreme angle and is completely enclosed in a tube to prevent any spills. This conveyor has a very large drive motor and gear box with a hydraulically controlled clutch and large disk brake, so that if there’s a problem on the barge, the conveyor can stop quickly.

“A 350-horsepower drive keeps the conveyor from overrunning,” Nicholson says. “With all that weight and momentum going down the hill, that conveyor would just take off if you had a small motor. We use about 125 horsepower to start the conveyor, and then it settles back to about 75 horsepower in an empty condition. When the material hits the belt, it actually goes into negative horsepower and regenerates power back into the grid. It’s a pretty unique conveyor system.”

It takes one operator in the tower on the dock and one person handling barge lines to control the loading of the barge. The operator can move the barge wherever he wants it during the loading process with the winch system. The conveyor will luft, extend, retract, and swing to reach all areas on the barge. The tug boats that bring the barge to the dock simply tie up to the barge and wait until loading is complete.

“We do 3 million tons per year, which sounds like a lot, but it’s 50 percent of what we’re used to doing,” Nicholson says. “In 2005, we did 6.2 million. We typically load 24/7, but we’re down to two shifts now, five days a week.”

The employees

Both Nicholson and Tweedy agree that the best part of DuPont Pit is the employees. “We have really high-quality employees here,” Tweedy says. “The current average tenure is 10.4 years for plant employees. They really take a lot of pride in what they do. We do most fabrication in house. We built all our own conveyors, feed distributors, chutes, and structural supports. The employees come up with many of the ideas, and we have our in-house engineer do the design drawings.”

One employee, Randy Davis, does all the programming for the plant’s automation system. “Randy started with us as a plant mechanic at Steilacoom in the mid ’80s,” Nicholson says. “In the ’90s, when we were getting ready for the DuPont Pit, we switched one of the towers at Steilacoom over to PLC control. Randy took an interest and had the knack, so he’s our programmer now.”

The programming is all Web-based. It can be accessed at the office or at home, so if there are any issues, they can be handled quickly, even at night. “The system is really reliable,” Tweedy adds.

As the economy improves, CalPortland plans to have DuPont Pit ready for it. “When we get so busy, as the industry did before 2008, we were able to have additional resources,” Tweedy says. “With this down economy, the real trick is trimming back while maintaining the assets and keeping safety and the environment at the forefront. That’s something that’s a priority here. The plant’s got to be ready to go all the time.” AM

From Aggregate Mine to Public Park

Steilacoom Mine opened in the 1890s and was rich with a deposit of fine, clean sand. “Originally, Steilacoom sluiced material using pumps in Puget Sound,” says Scott Nicholson, director of aggregates, Materials Group, Northwest Division of CalPortland. “They would bring barges in and put them up on the beach. They would, basically, sluice the material and bury the barges with sand and gravel. Then, when the tide came in, they’d tow it up to Seattle and manufacture concrete with unprocessed sand and gravel right off the pit face. At the time of its close, about 90 percent of the Seattle skyline had come from materials mined at our old Steilacoom plant.”

In the early 1990s, the mine entered into negotiations with Pierce County, and the county bought the property. The plant continued to operate, paying royalties to the county, until 2002 when it closed and locked its gates for the last time.

“Extensive construction work began on the Steilacoom plant right away after we left,” Nicholson says. “We had done some reclamation, but Pierce County had a vision of turning it into a huge park. The old mine site is now a park and a world-class golf course.”

The park includes walking trails that weave in and out of parts of the old mine that were left in tact for their historical value. Some of the old concrete stanchions that the plant was built on remain in the park, as well as the pond that supplied wash water for the old plant. The U.S. Amateur Championship was held at the Chambers Bay golf course this year, and the U.S. Open is scheduled to take place there in 2015.

EQUIPMENT LINEUP

Stationary Plant

Svedala 5×12 scalper

Svedala 8×24 double-deck screens (4)

Svedala 8×20 triple-deck screens (4)

McLanahan 12×48 classifiers (4)

McLanahan 66×36 double screws (2)

McLanahan 66×36 single screw

Conn-Weld 6×12 dewatering screens (2)

HP-500 Nordberg standard cone crusher

HP-400 Nordberg cone crusher (2)

ISC-82 vertical impact crusher

Barmac/ISC-82 vertical impact crusher

JCI 6×16 double deck for the standard crusher

8×20 Svedala SH double-deck screens (8)

85-foot High Flo thickener

Phoenix 3-meter belt presses (4)

Mobile Equipment

Caterpillar 992 loaders (2)

Caterpillar 990 loader

Caterpillar 988 loaders (3)

Caterpillar D10 dozers (4)

Caterpillar 40-ton articulated haul trucks (2)

Caterpillar Challenger 45 tractor

Caterpillar D6 dozer

Tiger 690 wheel dozer

To see a short video of CalPortland’s barge loading operation, visit this article in our digital edition at www.aggman.com.

Rather than start all over with a new plant, TXI invested time and money to bring its Bridgeport Stone operation into the new age.

By Kerry Clines, Senior Editor

TXI’s Bridgeport Stone operation is located in North Central Texas on top of a large limestone deposit that has kept the Dallas/Fort Worth area supplied with aggregate since the middle of the last century. “TXI bought the plant in 1953,” says Gary Allen, general operations manager for TXI.

More than 50 years of continuous growth brought 50 years of technology advances, but it also brought 50 years of inefficiencies that needed to be addressed.

“The primary crusher had a separate control building, the sand plant had a separate control building, the concrete products plant had a separate control building, and the asphalt products plant had a separate control building,” says Todd Lacey, plant manager at Bridgeport Stone.

If the plant was to stay productive and competitive, something needed to change.

Automating the plant

“We felt like we were leaving a lot of money on the table with the facility as it was,” Allen says. So, two years ago, rather than tear everything down and start all over with a new plant, the entire operation was automated.

TXI automated its old Bridgeport Stone plant so that the entire operation can be monitored and controlled by two operators in the central control room.

“We turned it on April 26, 2008,” Allen says. “We upgraded and automated the whole thing so we could run the entire plant out of one central location. We targeted the efficiencies and throughputs, and ultimately lowered our energy consumption by 25 percent.”

With all the individual operations running in a coordinated fashion and being controlled from one central location, the company was able to balance and fine tune the entire operation for optimum performance and production.

“The timing actually was great,” Allen says, “because the economy turned about the same time these improvements were completed, enabling us to operate more cost-effectively at a time when it was needed the most. Had the automation not been completed, continuing operational challenges and inefficiency would have made these last two years much more difficult. The results have exceeded our expectations, and, while it has taken us some time to get everything refined, it has really come together well.”

Before the plant was automated, one person was required in each control tower along with two ground hands to run each of the individual operations.

Instead of labor, the plant now has 15 cameras in strategic locations throughout the operation. The cameras are monitored and controlled by two operators in the central control room. “This is the heart of it all,” Lacey says. “We have people on the ground that can check things out, but for the most part, the two people in the control room run it all. One operator monitors the asphalt products plant, concrete products plant, and sand plant. The other operates the primary crushers, scrubbers, split bin, and the road base plant. They can speed the operation up or slow it down to optimize the production flow, and if you want to know what’s going on in the plant, you call them. It’s nice to go to one place and get every answer you need.”

The cameras can even be monitored and controlled from home, Lacey adds with a laugh, “but we try not to do it too often — it can become addictive, and we have to be careful.”

Streamlining operations

In addition to automation, Bridgeport Stone did several other things to streamline its operation and improve its bottom line.

Protective tire chains used on wheel loaders in the pit have saved the plant valuable time and money.

About a year ago, the plant began using tire chains on its wheel loaders. This has not only saved valuable time that might be consumed changing and repairing tires, but has also saved money. “If the tires didn’t have the chains on,” Lacey says, “out of four available tires on a wheel loader, we probably would have replaced two by now. Wheel loader tires are about $100,000 for a set of four, so the numbers speak for themselves.”

Along with this significant change, Bridgeport Stone installed upgrades to the major motors and pumps throughout the operation. The plant was able to reduce energy consumption by installing variable frequency drives on each of its crushers, which are some of the largest electricity-consuming units in the operation.

The facility’s water pumps were automated as well. “Two years ago, we ran five pumps at 350 horsepower each,” Allen says, “now we only run three.” Instead of leaving a 350-horsepower pump running all the time so the water truck can fill up, the company installed an automated, and much smaller, 40-horsepower pump. When the water truck drives under the spout, the pump turns on automatically, the water truck fills its tank, and then the pump turns off. And if the plant isn’t running, everything is turned off. “We only want to use the power that is required at the time,” Allen says.

The company also took advantage of the slowdown in business to improve its quality control. “At our quality control lab, we run an average of 850 samples a year,” Lacey says. “As the economy continued to slow, we looked at how to better utilize TXI’s technical resources at Bridgeport Stone. Enhancing our quality control was an ideal fit.” Samples are pulled from every stockpile and every 10th railcar after being loaded, so the employees know if there’s a problem with the material before the train leaves the plant. This increased sample frequency has allowed Bridgeport Stone to improve the quality of the material it ships while also providing important feedback to the operations to further optimize production.

The production process

Production begins with a bang. The quarry shots are highly coordinated at Bridgeport Stone to ensure maximum yield while effectively controlling any non-productive variability. “The protocol, when you shoot the shot, is absolute,” Lacey says. “We go through a rigorous process. We don’t have any deviation. You can shoot a thousand times and never have a problem, but we don’t take any chances. It just takes that one time.”

As in most operations, digital caps are used so that they can be armed with a computer and patterned to create the exact shot the operation wants. “We keep eight milliseconds of delay between blast holes and utilize seismograph reports to maintain optimum timing between rows,” Lacey says.

The goal of the blast is to get the shot fine enough so that 75 percent of the material passes straight through at the primary crushing plant. The primary is set up with two side-by-side, identical jaw crushers, providing the capacity to accommodate two 100-ton haul trucks dumping simultaneously. Once the material goes through the primary crusher, any oversize material will be retained on the top deck and then be routed to the cone crusher to be crushed again.

“If we choose to do so, there’s a conveyor that kicks out on one side so we can produce 12-inch rip rap product,” Lacey says. “To summarize, the primary crusher process can produce 12-inch rip rap, along with 5-inch by 2-inch material passing straight through, while anything over 5-inch is routed to the cone crusher to get processed one more time.”

Once the material is crushed, it is sized and sent on to the appropriate stockpiles, which are located at the base plant, sand plant, concrete products plant, or the asphalt products plant, where the material is ready for loadout.

“Our road base business had declined until early 2010, but demand has steadily increased over the last six months,” Lacey says. “As the sale of key products slumped during the economic downturn, the plant had more time to improve our road base process. We had some surplus equipment available to dedicate to this line of business, so we modified it and installed an additional stacker to create the automated base plant. Now we have the capacity to meet our business demand. We were less committed from a system standpoint before, and these changes have allowed us to better compete in an important market.”

Finished product is transported by both truck and rail. “Probably 25 percent of what we ship goes out by rail,” Allen says. “We have initiated a program to operate the train locomotives ourselves at the plant site, which has significantly — and safely — improved loadout efficiency. The railroad personnel pull the train in and get off, while we take control of the locomotive and load the train. After loading is complete, we contact them and tell them to come get it. We train our people — all personnel who operate the rail equipment complete a certification program to be qualified to operate the locomotives.” Once the trains are loaded and ready to go, they wait for what is known as the “rock window,” which opens after the Dallas/Fort Worth-area commuter traffic completes operations for the day.

Highway trucks handle all the local shipments. Loading takes place from 4:30 a.m. to midnight, but some trucks arrive at the plant as early as 2 a.m. to be the first in line. “We load trucks 5½ days a week, 20 hours a day,” Lacey says.

When it began operation in the “1950’s,” Bridgeport Stone was capable of producing approximately 300,000 tons per year. Currently, with the automation and other upgrades that TXI has made to optimize the process, the plant can now produce in excess of 8 million tons per year. Not bad for a 50-plus-year-old plant.

Future plans

Bridgeport Stone currently runs two shifts with a third shift reserved for maintenance.

“With the downturn in the economy, employees are currently working 40 hours a week,” Lacey says. “That’s down significantly from what they used to work. You really need four shifts to go 24/7/365. Before, we were doing it with two shifts, which, in retrospect, was not the optimum way to staff this plant. One thing our automation projects have allowed us to do during this downturn is to re-evaluate our staffing, improve our quality, and better plan for the time when higher levels of demand return to this marketplace.”

When business does pick up, as it surely will, Lacey plans to hire more employees as needed, but he has also challenged everyone currently on staff to maximize productivity.

“We currently have reserves capable of supporting this operation for many decades,” Lacey adds. “With these reserves and the level of technology in place today, we can continue to operate this plant for many years to come. But as newer technologies become available and continual optimization of the plant is required, it will likely bring more upgrades to Bridgeport Stone in the near future.” AM

Equipment Line Up

Mobile Equipment

Caterpillar 160M grader

Caterpillar 777F haul trucks (6)

Caterpillar 992G wheel loaders (3)

Caterpillar 988G wheel loader

Caterpillar 988H wheel loader

Caterpillar 980H wheel loaders (5)

Caterpillar 216B skid steers (3)

Caterpillar 914G clean-up loader

Caterpillar 773B 50-ton haul truck

Caterpillar 773B water truck

Caterpillar 320B track hoe

Caterpillar D-9N dozer

Caterpillar 834B rail car mover

Loadout Plant

Conveyors (4)

Loadout bins (3)

Tecweigh vibratory feeders with

Model 20 controls (5)

Tecweigh belt scale

Metso sizing/shaker screen

Asphalt Plant

Conveyors (14)

Fixed stackers (5)

Cemco Model 175 VSI crusher

Cemco Model 96 VSI crusher

Eagle Iron Works log washers (2)

Noble dual-flow vibratory feeders (2)

Tecweigh belt scales (7)

Metso sizing/shaker screens (5)

Concrete Plant

Conveyors (10)

Kohlman telescoping radial stacker

24-inch fixed stacker

Cemco Model 175 VSI crusher

Eagle Iron Works log washers (4)

Noble dual-flow vibratory feeders (2)

Tecweigh belt scales (4)

Metso sizing/shaker screens (4)

Sand Plant

Conveyors (3)

Radial stackers (2)

Eagle Iron Works classifiers (2)

Eagle Iron Works sand screws (2)

Tecweigh belt scales (2)

Metso sizing/shaker screens (2)