Operations

Taking Automation to the Next Level

Success in the Field
Reliable Conveyor Drives

Blasting Near Domestic Water Supplies – Facts and Myths Part 2

Tech Trends: Automation Innovations

Success in the Field

Reliable Conveyor Drives Critical for C&D Recycling

Drum motors eliminate exposed components and provide space-saving drive systems

Brossart Materials Recycling crushed and screened rubble from Cinergy Field with an Eagle Crusher Ultramax 1400-45 crushing plant equipped with Van der Graaf drum motors.

Many construction and demolition (C&D) recycling operators reluctantly accept lost production and high maintenance costs associated with conventional conveyor drives and accessories, according to Bill Compton, service manager for Eagle Crusher Co. “For example, typical portable crusher drives use a motor and a series of V-belts to drive the conveyor belting,” he said. “Maintaining [this] traditional drive system adds unreclaimable costs.”
Switching from external belt drives to internally powered drum motors can help eliminate the problems and the costs. Compton cited maintenance savings and fewer drive-related production interruptions as benefits provided by drum motors.
Uptime is important for the growing recycling industry, which Compton said is spurred by two factors. He listed governmental requirements to reduce the amount of refuse buried in landfills as the first. Cost savings realized by using recycled material for roads, landscaping, construction, and power generation is the second.
“Keeping our machines up and running at all times is key to customer satisfaction,” said Compton. “Originally our plants used conventional exposed drive systems that included baseplates, chains, chain guards, sprockets, pillow blocks, and external motor/gear reducers. About 10 years ago, we switched over to an internally powered drum motor design that eliminated the external parts, but we were having a problem with durability. We offer a one-year warranty on all of our systems and we had motors failing within the warranty period. At one point our failure rates reached an unacceptable 50 percent. This number is more significant when you consider that each year we build more than 50 plants,” said Compton.
Eagle Crusher’s local distributor representative, Kerry McConnell of Vancon, convinced the company to try a new motor manufactured by Van der Graaf. “We installed the first motor about 2-1/2 years ago and it’s still running strong,” said Compton.
“The space-savings configuration of the drum motor allows for a simple and economical conveyor drive system,” Compton said. “A mechanic installs two mounting brackets, one at each end of the motor, sets the motor in place, and makes the electrical connection to the external terminal box. Drum motors are quiet and clean; they require almost zero maintenance.
“Another benefit of the compact [drive] design is our ability to use a larger diameter head pulley,” Compton said. “A larger head pulley allows the belting to make a more gradual 180° turn, which reduces the strain on belt fibers. The reduced strain results in significant belt life increases.”
The constant pounding and jagged edges of C&D debris on the conveyor belting plus the harsh environment and exposure to weather conditions are some of the factors that cause conveyor maintenance problems. If a conveyor belt stops for any reason, the entire C&D operation comes to a halt.
A situation that can arise in asphalt recycling is oil leaching. “The oil attacks the conveyor belting and may adhere to typical drum motor lagging,” said Compton. “If the oil is allowed to build up on the motor face, belt slippage could occur and belt tracking is a concern. Belt slippage causes production inefficiencies and the tracking problem may cause the drum motor shaft to deflect, affecting motor performance. McConnell suggested trying a drum motor with metal tread lagging. The metal tread lagging eliminates oil build-up and maintains the proper belt traction needed in the asphalt recycling environment.”
With fewer drive-related production interruptions, C&D waste recycling operators can enjoy increased production without costly maintenance expenses.

the bottom line...
Switching from external belt drives to internally powered drum motors can provide maintenance savings and fewer drive-related production interuptions in C&D recycling operations.

---

Blasting Near Domestic Water Supplies – Facts and Myths

Part 2 of this two-part series summarizes the water quality and quantity components of a pre-blast water well investigation

By Douglas Rudenko, Gregory Love, and Thomas Novotny

Most domestic water well owners know very little about their well or its maintenance. Any information they may have is vague and often exaggerated. Additionally, many well problems occur in the bottom where no one can observe them. The old adage “Out of sight – out of mind,” seems to be the only way to explain this lack of maintenance history.
It often is prudent, therefore, for explosives users to gather some preliminary data on surrounding wells to protect against unwarranted damage claims. For large blasting projects it is beneficial to conduct pre-blast tests to characterize the quality and quantity of the aquifer in surrounding wells. Smaller-scale or lower-budget blasting projects could limit the testing to water quality and perhaps a measure of the static water level. The proactive approach to this problem is a benefit to the blaster and the well owner.
A pre-blast water well investigation should consist of four components: a comprehensive interview with the well owner, inspection of the available water-supply system, water quality analysis, and water quantity measurements. This article focuses on the latter two components – water quality and quantity.

Water Quality
The most common tests to help characterize water quality and provide insight into potential problems are pH, conductivity, total dissolved solids, total suspended solids, sulfate, nitrates, total iron, manganese, coliform bacteria, alkalinity, and acidity. The U.S. Environmental Protection Agency established maximum contaminant levels (MCLs) that are used by most state and federal agencies as a guide to determine if a drinking water source is suitable for human consumption. These MCLs are indicated by an * in the following discussion.
A standard groundwater test is pH, a measure of the hydrogen ion concentration and an indication whether water is acidic (pH < 7), neutral (pH = 7), or basic (pH > 7). The normal range for groundwater is 6.5* to 8.5*. The pH of near-surface groundwater tends to be lower due to humic and carbonic acids derived from the soils and the atmosphere. Water with a pH level less than 6.5 may be corrosive to metal pipes and may leach lead solder from joints. Low pH may be an indication of acid mine drainage (AMD).
Conductivity also is a standard groundwater test that specifically measures the ability of water to conduct electricity and is an indication of the dissolved solids content. Primary dissolved solids include ions of calcium, magnesium, sodium, chlorine, potassium, bicarbonate, and sulfate. Conductivity levels below 850 umhos/cm are normal. Elevated levels may indicate salt-water intrusion or AMD. The conductivity of shallow groundwater (springs and dug wells) is considerably less than deep groundwater (drilled wells). Total dissolved solids (TDS) should not exceed 500 mg/l*.
Total suspended solids (TSS) is a measure of solid material suspended in the water. Suspended solids tend to be elevated in springs and near-surface groundwater due to the presence of organic material and chemical precipitates. Elevated TSS is common in water affected by AMD. TSS in deep groundwater is very low; however, when brought to the surface and oxidized, iron in the water readily forms a suspended solid. The TSS content in deep, iron-free well water rarely exceeds 1 mg/l.
Sulfate tests primarily are used for detecting and measuring AMD. Elevated sulfates are a characteristic of AMD, although high levels are commonly found in alkaline formations, such as shales. Levels above 250 mg/l* may cause a laxative effect in humans.
Nitrates are tested for several reasons. Elevated nitrate levels are an indication that the water source may be contaminated and have coliform bacteria present. Therefore, this test can be used as a guide if coliform bacteria testing is unavailable. Nitrogen levels above 10 mg/l* can cause Methemoglobinemia, a dangerous blood disorder that can affect infants. Sewage or agricultural fertilizer also can cause elevated nitrate levels. Explosives are commonly nitrate-based and although consumed during the detonation, the measurement of before and after blast levels of nitrate can aid in reducing liability exposure.
Total Iron, a standard groundwater test, is a measure of all ferric and ferrous iron in the water. The iron content becomes elevated in waters affected by AMD. Homeowners often suspect a change in iron content as a result of blasting. Near-surface groundwater generally has very little iron, considerably less than 0.3 mg/l*. Although there are no known health risks associated with high concentrations of iron, levels above 0.3 mg/l may cause unpleasant taste, objectionable appearance, and staining.
Manganese is primarily tested to detect and measure AMD. Its chemical characteristics are very similar to iron and water affected by AMD tends to test high in manganese. Elevated levels are not known to be harmful to humans, but levels above 0.05 mg/l* can cause unpleasant taste, objectionable appearance, odor, and staining of plumbing fixtures or laundry.
Coliform bacteria is a standard test to determine potability of water and requires careful sample collection, handling, storage, and testing. The sample needs to be collected under sterile conditions, kept cool in storage, and delivered to and processed by a microbacterial laboratory within 24 hours. Homeowners sometimes are concerned that blast vibrations may have caused the well casing to break or shift, thus allowing entry of contaminated surface waters. The presence of only one* colony-forming unit per 100 ml of water is considered unacceptable, since its presence means that dangerous bacteria or virus may be present. If water tests positive for coliform bacteria, many regulatory agencies require further testing, such as fecal coliform. Coliform is very common in the near surface groundwater of springs and dug wells. Many families have been drinking the water for years without ill health. This may be because the harmful bacteria commonly associated with Coliform is not present, or that perhaps the family has acquired a resistance to the bacteria.
Alkalinity is a standard groundwater test used to detect and measure AMD. Alkalinity measures the ability of water to act as a buffer against acids, such as sulfuric acid (H2SO4), and is a measure of the ability of water to resist becoming acidic in the presence of AMD. In general, water that is more alkaline can resist becoming acidic. Such water typically has elevated pH and hydroxyl species that can neutralize acid. This type of water is more characteristic of groundwater found in deep wells. Common alkalinity levels for deep groundwater is greater than 150 mg/l CaCO3. Shallow ground water has low alkalinity, less than 10 mg/l, and is very poor at resisting the influx of acid water. In general, the alkalinity should be greater than the acidity.
Acidity is a standard groundwater test that also is used to detect and measure AMD. Acidity is a measure of the ability of acidic water to return to a more alkaline state with the addition of a base, such as sodium hydroxide. Deep ground water typically requires a large volume of base in order to become alkaline. Near-surface water typically requires the addition of very little base in order to become alkaline. In general, the alkalinity should be greater than the acidity.*

Quantity Tests
Homeowners often have a considerable financial investment in their wells and, because of this, are very protective of them. In a rural setting where public water is unavailable, the overall value of their home and property is based on the presence of an adequate supply of well water.
Nevertheless, we have learned through our experience of well testing and of handling claims of diminished or lost well water supplies that very few homeowners actually know the capacity and supply capability of their well — unless it routinely runs dry. We commonly find gross over-exaggeration of the amount of water that a well supplies.
We also find that, due to the expense of drilling a well, some owners of inadequate wells may try to blame blasting for a lack or loss of water. Many claims of diminished or lost supply come in late summer and early fall, due to the seasonal lack of rain. Unfortunately, this time period coincides with most quarrying and construction activity in the northeast.
It is advantageous to have capacity testing done before any construction begins on a project to establish a baseline for after construction comparisons. There can be considerable discussion on which wells may need capacity testing, based on their proximity to the construction site and on the local geology.
Once chosen, a drawdown-recovery test can be conducted to characterize the well. Depending on individual well characteristics, the goal is to establish static water level, well depth, productivity of the well in gallons per minute per depth, and possibly the depths of groundwater inflow points. This information, when incorporated with the results of a chemistry test, allows a complete characterization of the well. After construction and blasting is completed, the exact same test procedure can be completed, if necessary, to determine if there has been any change to the quantity and quality of the well water.

Douglas Rudenko, P.G.; Gregory Love; and Thomas Novotny, P.G.; are with Vibra-Tech Engineers, Hazleton, Pa. This article is based on a more extensive paper presented during the 4th Biennial Blasting Vibration Technology Conference sponsored by Geosonics/Vibra-Tech. The theme of the conference was “Overcoming the Public’s Perception of Blasting.” For more information on the next Blasting Vibration Technology Conference, please call Laura Lee at (724) 934-2900.

Tech Trends

Automation Innovation

By Bob Drake

Roughly divided, aggregate operations have three distinct but connected operational areas — the pit, the plant, and the market. Although developments in automation have been applied simultaneously in several of these areas, it is interesting to note how innovation generally has progressed in a cycle from one area to the next.
Primitive desktop and bulky mainframe computers first invaded aggregate company offices about 30 years ago, handling market functions such as ticketing, billing, and other administrative duties. Next, programmable controllers, more powerful desktop computers, and sensors were adapted to processing plant environments, enhancing crushing and screening productivity. Subsequent development of microprocessors allowed haul truck, wheel loader, excavator, and drill manufacturers to monitor and control machine functions.
Most recently, the Internet, wireless communications, and global positioning systems (GPS) have begun a second automation cycle, once again affecting aggregate producers’ interaction with their customers.
Industry-wide implementation, however, is inconsistent. The ability to automate a plant or machine function isn’t always justified by need or by its cost effectiveness. Nevertheless, today’s automation capabilities provide an indication of what may become commonplace in aggregate operations within a few years. The following selection of recently introduced or upgraded products demonstrates the expanding potential for automating pit, plant, and market functions.

IN THE PIT
1. Atlas Copco ROC D7 C
Computerized functions on Atlas Copco’s ROC D7 C surface crawler drill enable the machine to automatically drill holes unattended, such as during operator lunch breaks and between shifts, the company said. The operator sets the hole depth and automatic feed alignment and initiates drilling. Rods are added to the drill string automatically. ROC Manager software enables producers to design drill plans in the office and send them to the drill rig. The system monitors the drilling operation and logs deviations and other data. InfoExpress 701
2. Cat/Trimble Computer-Aided Earthmoving
Caterpillar and Trimble formed a joint-venture company, Caterpillar Trimble Control Technologies, to develop “the next generation of advanced electronic guidance and control products for earthmoving machines.” One product that will be sourced from the joint venture is Cat’s latest Computer Aided Earthmoving system — CAESultra. The system uses GPS, on-board computers, software, and wireless communications to integrate mine planning and production. CAESultra can eliminate in-field surveying and staking and can be used to achieve a desired grade on a haul road or reclaimed surface; to selectively mine; and to track machine productivity. Production data can be exported into common databases.

3. Komatsu Komtrax
Komatsu developed an equipment tracking and reporting system for its dealers called Komtrax. The system uses a machine-mounted transmitting unit and GPS and telecommunications satellites to provide real-time location and service-hour readings over the Internet. Komatsu expects to expand the system to transmit additional machine readings, including engine speed, fuel levels, oil pressure, battery voltage, operation mode, and error codes.

IN THE PLANT
4. AMR Human-Machine Interface
American Mine Research’s (AMR’s) Human-Machine Interface (HMI) provides a graphical depiction of the processing plant that allows a user to visually monitor all operating aspects. Off-the-shelf sensors on equipment allow the system to control bin and crusher bowl levels and to shut down plant circuits when problems occur. The Windows 2000/XP-based HMI program can create original screen views and provide production reporting and trending.

5. ATEC Jobclock
ATEC introduced a hardware and software package called Jobclock for remote job time and attendance tracking. A battery-powered, weatherproof timeclock is mounted at the job site. Employees clock in and out using small buttons designed to be carried on their keychains. Attendance records are downloaded to a PDA via an infrared strobe and then transferred to the PC-based Jobclock software for job cost tracking and payroll, eliminating hand-written time cards.

6. GreyStone Aggre-Spec III
GreyStone offers a Windows-based, computer-aided sand reblending system called Aggre-Spec III. It features a three-method system from which Aggre-Spec III automatically selects the most efficient method for reblending up to three products, according to the company. The system then monitors the feed material and maintains product specs, warning the operator of potential mix or mechanical problems.

7. HSS Sampling/Tramp Removal Systems
HSS, a division of McLanahan Corp., offers automatic sampling systems for taking a cut from a stream of material on a moving conveyor belt. A cutter, activated by push button or automatically on a timed basis, sweeps a sample from the belt into a collection chute. The system also can be used in conjunction with a metal detector to automatically remove tramp metal from a conveyor without shutting down the belt.

8. K-TEK Guided Wave Radar Level Detector
K-TEK’s MT2000 new guided wave radar provides level measurement with an accuracy of +/-0.20 in. in hoppers, bins, silos, sumps, and tanks, according to the company. A metallic probe acts as a wave guide to direct microwave pulses and eliminate beam divergence. Therefore, there are no false signals or echoes from objects other than the solid or liquid product being measured, K-TEK said. The MT2000 non-contacting probe can be cut to length, from 2 to 100 ft.

9. Nesco AquaLog
Nesco introduced the AquaLog, a system to monitor water volume used to control dust in quarries. The AquaLog measures water pressure and flow and displays the values in an X-Y plot versus time. Phone line or wireless connections allow remote observation. The AquaLog enables plants to comply with state or federal EPA recordkeeping requirements. Interfaced with a belt scale, the system can be used to determine the amount of water added per ton.

10. PTI Real-Time Quality Control
Pavement Technology, Inc. (PTI), an Astec company, developed its Real-Time Quality Control (RTQC) system for aggregate plants by combining a Superior Industries Automatic Belt Sampler (see below) with PTI’s Automatic Gradation Unit. The RTQC collects a sample from a moving conveyor belt and drops it into the gradation unit. The gradation unit shakes and weighs each fraction and sends a gradation report to the control room in an Excel spreadsheet format. The process takes 10 to 12 minutes per sample, according to PTI.

11. Rockwell Automation Smart Bearings
Rockwell Automation’s Dodge Smart Bearings have housings predrilled to accept a variety of sensor kits that measure temperature every 16 milliseconds, speed continuously, and vibration every 10 minutes. Use of the bearing sensors in conjunction with the company’s EZLINK system and a DeviceNet-capable PC or PLC allows automated control of mechanical power transmission equipment. Optional EZLINK software provides trending and analysis tools useful for predictive maintenance of bearings and rotating equipment.

12. Rotex Gradex 3000
Rotex’s Gradex 3000 particle size analyzer performs automatic sieve analyses. The PC-controlled unit classifies and weighs each sieve fraction; calculates and stores weights; and reports the data to the PC. An AutoFeed option handles up to six samples without the interaction of lab technicians. The same shaking, brushing, and weighing procedure is repeated on each sample, Rotex said. The Gradex 3000 analyzes up to 13 size fractions using a stack of standard 12-in.-diameter, half-height round text sieves.

13. Siemens Milltronics Levelwatch.com
Siemens Milltronics Process Instruments introduced an Internet-based inventory management service called Levelwatch.com for remote monitoring of storage silos, bins, and tanks. The service provides material level data, alarms, trending graphs, history, and administrative reports online at a secure website. Field data, measured by ultrasonic, capacitance, or radar sensors, is sent via landline, wireless modem, or satellite. Designated personnel can receive alarms by any combination of phone, fax, pager, or email.

14. Superior Ind. Automatic Belt Sampler
Superior Industries, an Astec company, offers an Automatic Belt Sampler (ABS) for obtaining sweep samples from moving 24- to 60-in.-wide belts. The pneumatically operated ABS retrofits to most points along existing conveyor structures and can be hooked to plant air lines or equipped with a self-contained compressor. It is available with manual push button or automatic-timed controls. The standard 18-in. cutter has replaceable UHMW wear plates. Adjustable Garland idlers conform the belt to the the cutter’s sweep.

IN THE MARKET
15. AWS Unattended Truck Scale Systems
Advanced Weighing Systems (AWS) offers unattended truck scale systems and software for automated transactions. The system can handle transactions using stored tare weights or incoming and outgoing weights. Drivers enter a truck ID code or swipe a bar coded badge at a data terminal to begin the process. AWS’s Interact software is the interface between the digital scale indicator/controller and a central database. The system works on any brand scale that provides a load cell connection to a digital indicator, the company said.

16. Command Alkon COMMANDaggregate
Command Alkon’s Windows-based dispatching application, COMMANDaggregate, operates on a single PC or on local or wide area networks. It can be adapted to centralized or decentralized operations, the company said, and integrated as needed with other modules, such as Truck Tracking or Map Truck Tracking. Truck Tracking displays the status of all scheduled orders and trucks, including trucks in the yard. Map Truck Tracking shows the actual location of selected trucks on a map.

17. Dexter + Chaney Document Imaging
Dexter + Chaney’s Forefront Construction Management software includes document imaging capability to electronically store documents associated with transactions, such as vendor invoices, time cards, contracts, and customer billings. The documents can be viewed on screen, emailed, or faxed without printing. Document imaging is fully integrated with Forefront’s accounting function, but documents for any purpose can be scanned, filed, viewed, and annotated, creating a “virtual filing cabinet,” Dexter + Chaney said.

18. ENSR International Geofilm
Geofilm, from ENSR International, combines airborne DVD film with a simultaneously moving map and custom database. According to the company, the technology has been used for planning and monitoring construction of highways, railways, and pipelines; environmental surveys; public planning hearings; and before-and-after comparisons.

19. GE Capital I-Sim Driver Training
GE Capital I-Sim opened its first Driver Development Service Center in Atlanta. The facility features virtual training using a full-size, fully operational truck cab placed in a three-dimensional cinema. Driver training includes use of the simulator, as well as classroom instruction and computer-based training. The company plans to open additional service Centers in Anaheim, Calif., Chicago, Dallas, Denver, Philadelphia, and Salt Lake City.

20. JWS Apex System
JWS offers the Windows-based Apex System for creating and processing truck scale tickets. The ticketing module directly interfaces with most digital scale indicators, JWS said. An Auto ID add-on module allows use of radio frequency (RF) tags or RFID cards to identify trucks. Possible system configurations can include traffic lights, touchscreen driver interface, and remote ticket printing. The JWS loadout system includes a PLC control panel and loadout software to open and close the gates on overhead bins.

21. Kester Software aggreSOFT
Kester Software’s aggreSOFT 3.0 allows companies to collect invoice, material hauling, and payroll information from drivers in the field using wireless devices such as a phone or PDA. This reduces data entry and the time required to generate QuickBooks invoices, payroll reports, and hauling reports, the company said. AggreSOFT is provided on a subscription basis.

22. Snead Management Rail Log System
Snead Management Systems’ Rail Log software helps shippers manage rail car inventory, weighing, and billing electronically. Rail car information — track location, owner, car number, condition, and type — can be collected using a PDA. The system can handle invoicing for both the haul and the product or for just the product, with the railroad invoicing for the haul. Communication with the Rail Log system can be done over the Internet using the latest railroad file formats, such as 404, 440, or T94.

23. Trimble/Systech Fleet Management
Trimble and Systech integrated Trimble’s Telvisant Mobile Resource Management System with Systech’s Advantage Dispatch 8.0 software for ready-mix and aggregate truck fleets. Telvisant uses sensors, GPS, and Internet-based truck tracking to automatically provide location and status information to dispatchers through the Advantage software — without driver intervention. Job tickets are sent to drivers on in-vehicle displays.