The Feltes name has been synonymous with mining in Illinois since before the Great Depression. In 1920, Leonard Feltes and Joseph Feltes bought the Petit Coal Co. in Batavia, Ill. Five years later, they bought their first gravel operation. Over the decades, the business passed from one generation of Feltes to the next and evolved with technology.

In 1945, Leonard's sons Howard, Laverne and Clarence joined the legacy. When Howard died in 2000, his son Tim Feltes and nephew Richard Feltes took the company's helm. Tim had held positions in both operations and finance with Martin Marietta Materials between 1979 and 1985.

Today, the Feltes Sand & Gravel in Elburn provides Fox Valley, which is about 50 miles west of Chicago, with 1.5 million tpy and employs about 30 people. This marks significant growth compared with the 250,000 tons the company produced in 1971. The site covers 500 acres of owned and leased land with sand and gravel deposits exceeding 75 ft.

Tim Feltes, now vice president, says the market was more than 25 miles east when the plant first opened, keeping demand low. And even into the 1980s, the operation only produced about 650,000 tpy. But soon people started migrating to Elburn, and demand increased. A housing boom in the 1990s finally pushed the company to its current production level.

To keep pace with the growing demand, the Felteses expanded their operation through continued technological upgrades. Those upgrades will be on display when the National Stone, Sand & Gravel Association tours the site in October as part of its automation conference.

Feltes Sand & Gravel began using automation technology 10 years ago with an automated scale system, Tim Feltes says. The system relied on bar codes and required the drivers to swipe cards when entering and exiting the plant. The cards carried vehicle weights and load information.

The downside to the system was that cards were routinely lost or damaged. In 2001, they were abandoned for radio frequency identification tags that proved more effective.

As a truck enters the yard, its tag is read and its information displayed on a scale clerk's computer screen. Drivers rarely need to stop on the way in because the tags can be read while the truck is moving as fast as 10 mph. On the way out, the driver stops on one of two outbound scales, the tag is read again, and the driver's ticket is printed in a booth near the exit.

Such efficiency has a price tag. “The initial investment is costly,” Feltes says. “But, we've got the system employed now to where the costs are manageable.” Payback on the RFID system was about one year.

The next step was installing an Allen-Bradley IntelliCenter and upgrading an Allen-Bradley SLC 5/05 to an Allen Bradley ControlLogix Programmable Logic Controllers. A wireless Ethernet network was installed to link the plant's PLCs, control tower computer and office network. This reduces the need for conduit, a burden when rearranging a plant. This wireless Ethernet, installed by PCS Technologies, provides the main communication link between the PLCs and Human Machine Interfaces.

This system provides some of the groundwork for Engineered Software Products' OpenPlant Control. ESP is a control systems integrator offering system designs and data management solutions. ESP has completed more than 150 automation projects for crushed stone and sand and gravel operations during the past 15 years.

OpenPlant Control is its aggregate solution comprised of off-the-shelf PLCs, HMIs and database products. Each solution is customized.

The HMI becomes the operator's window that brings the entire operation into focus, in real time. PLCs are hardwired to various plant motor controls and field sensors including speed switches, level probes, belt scales, etc. The PLCs, which can be compared to a central nervous system, execute a custom program that determines how equipment should be running.

The HMI is comprised of various graphic screens including overviews, detailed pop-ups, alarms, trending, downtime, diagnostics and menus. The HMI at Feltes Sand & Gravel is in a control tower.

The overview screens provide a general overview of the entire plant and its material flow. Color animation indicates what devices are running, stopped or in alarm. It also features a navigation capability and an auto-start and auto-stop function, which starts or stops every component in a logical sequence with a mouse click.

Operators also can start and stop individual components through device pop-up screens. The screens offer more in-depth information on each piece of equipment. If there is an unscheduled stop due to a malfunction, the window would indicate that problem from a list of potential causes including pull cord, failed to start, power trip, overload, high-amp shutdown, zero speed trip, etc.

The system also has protective and sequential interlocks that prevent material back-ups during equipment failure. In other words, conveyor 2 needs to be running before conveyor 1 can start, and if conveyor 2 trips then conveyor 1 trips. When something does trip, chances are that the control system knows why and will store that information for future analysis.

“With today's technology, when devices go down, the operator has all of this information at his fingertips,” says Jeff Patenaude, a principal of ESP. “He can get on the radio and dispatch an electrician to reset the overload on conveyor 2, for example.”

The various tools of the HMI can even provide early warnings to impending problems based on preset parameters such as temperature or amp levels. With the right field sensors, effective programming reacts automatically to prevent mishaps. HMI tools such as historical trends, alarm logs and PLC diagnostics also can give early warning to forth coming problems.

“Those are the real benefits,” Tim Feltes says. “Just to have the information is one thing, but to be able to analyze the information and to understand exactly what is going on in the plant at any given moment is the real benefit.” That information can be used to adjust production and improve plant maintenance.

The AB IntelliCenter MCCs with DeviceNet protocol makes an abundance of information available. Installing it was a smart move for Feltes, according to ESP engineer Joe Becker. The IntelliCenter MCCs' digital technology reduces the number of wires and relays needed. Instead it ties into one network. The parameters are actually inside the electronics and accessed through a digital communications link. This allows more information to be shared through less hardware.

“Our ultimate goal is to relate that information to product quality,” Feltes says. “As we see the process changing dynamically we can begin to log that and use trend analysis to assist us in operating the most efficient ways possible.”

For example, Feltes has been able to maximize the tertiary crushing by equipping its crusher with a bin level indicator that communicates to the system. Before, the operator was slightly scaling back production to compensate for the occasional surge of material. Feltes says it was human to do so because the operator occasionally had to dig the crusher out by hand if it was overfed.

Plant Manager Dan Bree says the 40-in.-high hopper is set to consistently remain between 20% and 100% full. “(The system) is definitely a lot more precise as far as control feed to the plant. That is working great, better than I expected,” Bree says. “It's holding a steady ton through the plant.”

Once the parameters are set and the software debugged and fully operational, the plant will run consistently until a problem occurs or adjustments are made. “These PLC systems are so reliable,” Patenaude says. “I have seen PLCs in operation for over 10 years that required little attention.”

Because there are so many preprogrammed diagnostics, the system can usually troubleshoot itself, Feltes says. If not, ESP can view the settings in real time from its office in Atlanta. They can communicate with the system directly, change parameters, watch the response and even change crusher loops.

ESP also integrates Web-based reporting into OpenPlant Control. The reports are intended to be used as a real-time tool for decision making and evaluation. An HMI viewnode in Bree's office allows him direct access to the reports being generated.

The extent of the information available, however, directly relates to the investment. “Belt scales are expensive. And speed switches cost money to put in, so a plant manager has to make a decision,” Patenaude says. “He can't put a speed switch everyplace he wants to put a speed switch. He would be spending a fortune. There's also a whole other cost associated with the electrician getting it all wired up, running conduit, pulling wire, getting devices installed and wired.”

Patenaude says a plant owner needs to find a happy medium between the cost and what he or she wants accomplished. As a rule of thumb, the more feedback the PLC gets through field sensors, the more automated a system will be and the smoother it will operate. Payback is often estimated to be about one year, Patenaude says. It comes in the form of enhanced quality, increased production and decreased downtime. A plant owner can draw the line based on his cost-benefit analysis and expand later as did Feltes Sand & Gravel.

“One of our main objectives was to bring this processing plant that is crushing, washing and sizing at 1,300 tons an hour under the control of a single plant operator,” Feltes says. “The next milestone here is going to be applying automation and control technology to our primary crushing and field conveying systems.”

Taking it one step at a time, an operation can keep pace with the market. If that market should double overnight, an automated plant would be more likely to meet it.

“We are not at the maximum of what we think we can produce, but we are producing, at this point, what the market is presenting to us.” Feltes says. “As the market grows, we will look to meet that demand.”

Wireless Information Revolution Approaches Aggregates

By Adam Madison

The Information Revolution is thriving with the likes of cell phones, the Internet, and preferred-customer cards. It seems no information escapes the vault of expanding computer archives that can communicate over long distances. Wireless Ethernet radio equipment seems to be the next technological revolution for material processing. Feltes Sand & Gravel Co. in Elburn, Ill., which was one of the first to pick up on the technology, is using it to provide the central communication link to its automation system. It relied on Alvarion's BreezeAccess, which was installed by PCS Technologies.

BreezeAccess provides wireless broadband connectivity for Telco's service providers and network managers. It has mixed-spectrum and multiband solutions that provide IP for wireless access and networking connectivity. It operates within 5.725 GHz and 5.850 GHz bands and facilitates data rates up to 54 Mbps, which requires zero licensing.

The strength of this equipment comes from its non-line-of-sight technology, says PCS Technologies General Manager John Feldman. No longer do antennae require clean optical lines of sight to communicate. If a stockpile falls between the line of sight, the signal from one antenna will bounce off the pile and find an alternate route to the next antenna. Line-of-sight technology, on the other hand, would lose its connection. “(It) allows flexibility in change and configuration,” Feldman says.

The BreezeAccess eliminates the need to run relays, enabling the programmable logic interfaces to communicate more information through the wireless Ethernet and then up to the human machine interface in the control tower. Without wires and conduit running overhead and underground, operators can change a plant's design at anytime. They just move the equipment, put the central antenna back up and point the PLCs' antennae back to it.

Wireless Ethernet radio equipment also allows operations to add the most cost-effective technologies. Wireless phones and closed-circuit cameras can be incorporated, as well as the usual scales and sensors.

The wireless Ethernet also allows outside computers to tie into the machine. Dan Bree, Feltes Sand & Gravel plant manager, can monitor the plant as it runs. And PCS in Minnesota can access the computer for trouble shooting, maintenance and customer service.

Radio technology, however, may be subject to certain interference, particularly near cities, Feldman says. But because signals typically remain in the confines of quarries below the grade of city streets, interference is seldom encountered. If it becomes a problem, there are three frequency sets operators can use. Huge elevation differences within quarries may pose problems for maintaining connectivity. In this instance, operators may still rely on relays.

But, despite a minor risk of interference, the technology is proving effective. PCS has installed hundreds of wireless Ethernet systems for several industries including the railroad and municipalities. It's also used for telecommunication and military applications. And it looks like aggregates is catching on.

Equipment List

Mobile Equipment

• Cat 992-C wheel loader (pit)
• Cat 980-G wheel loader
• VME L-480 wheel loader (pit)
• (2) Cat D-9N dozers
• Bucyrus Erie 88-B dragline crane

Crushers

• Kolberg-Pioneer 3042 jaw crusher
• Lippmann Milwaukee 3650 jaw crusher
• Hazemag 1620KH horizontal impact crusher
• El-Jay 54-in. cone crusher

Screens & Conveyors

• Deister 8- × 20-ft triple deck
• (4) Deister 6- × 20-ft triple-deck
• Eagle Iron Works 46-in. × 35-ft double log washer
• Eagle Iron Works 30-in. × 18-ft single coarse material washer
• (2) Eagle Iron Works 12- × 48-ft classifying tanks
• (2) Eagle Iron Works 54-in. × 34-ft double fine material dewatering screws
• (2) Eagle Iron Works 44-in. × 32-ft. double fine material dewatering screws
• Eagle Iron Works 36-in. × 25-ft single fine material dewatering screw
• Portec 36-in. × 3,100-ft conveyor system
• Process Machinery 42-in. × 2,400-ft conveyor system