August 2002
Part 1 in a series on research that refutes claims of water well damage from blasting operations
By Douglas Rudenko, Gregory Love, and Thomas Novotny
The average American uses 100 gallons of water for domestic use on a daily basis. Changes in this vital resource, which immediately affect a family’s quality of life, can cause alarm because many people are unfamiliar with the nature of groundwater movement or the design and maintenance of their domestic water supply.
With the average life expectancy of a well being about 20 to 40 years and that of the pump about five to 10 years, problems with domestic water wells are common. Many domestic well owners, however, expect their well and well components to last indefinitely. When faced with the unplanned expense of a sudden well-system failure, nearby blasting operations — rather than overdue maintenance or long-term aquifer depletion — are often the scapegoat.
Common complaints heard by quarry operators and explosives companies include loss of water supply and changes in water odor, taste, and color (Table 1). A lack of knowledge about domestic water-supply systems coupled with widespread misunderstanding of the effects of blasting and ground vibrations often leads to unfounded damage claims.
| Table 1: Common Water Well Problems | |
| Problem | Possible Cause |
| Low yield | Pump capacity exceeds well recharge rate; natural depletion of aquifers; inadequate well bore storage |
| Reduced water supply | Groundwater level lowered by area development (new wells); iron and/or sulfur reducing bacteria; worn out pump; seasonal level fluctuations |
| Slime | Bacteria growth supported by iron or organic sulfur compounds in water |
| Coliform contamination | Direct connection to surface water through inadequate grout seal, worn casing, cracked seals or fittings; poor sanitation during well maintenance; aquifer contamination (i.e. karst terrain) |
| Nitrate contamination | Coliform and fecal coliform bacteria contamination (see above) |
| Carbonate crusts plugging pipes and well bore | High concentrations of calcium and magnesium ions (hard water) |
| Rotten egg odor | Hydrogen sulfide gas from natural sources or sulfate-reducing bacteria |
| Red staining/objectionable taste | Natural iron concentration greater than 0.30 mg/l |
| Black staining/objectionable taste | Natural manganese precipitated from water; associated with iron |
| Bitter taste/laxative effect | Natural sulfate concentration greater than 250 mg/l |
| Blocked pump | Sloughing or caving of well bore |
| Dry well | Extreme seasonal groundwater level fluctuation |
Rock-Fracturing Facts
Homeowners’ primary concern when blasting is nearby is its effect on the various structures comprising their residence, including the effect on the integrity (quality and quantity) of their water supply system. Homeowners envision blasting as the fracturing of rock and usually assume that since they feel vibrations at a great distance, rock fracturing also must occur at this distance. Most homeowners then worry about a diminished or contaminated water supply.
Blasting always produces vibration or seismic waves. In order to fracture rock, however, the explosive energy must exceed the elastic limit of the rock. As fracturing occurs, the energy is used up, eventually falls to a level less than the strength of the rock, and fracturing stops. Because the remaining energy is below the elastic limit of the rock, the rock momentarily deforms but returns to its initial state unchanged. This zone of elastic deformation results in the generation of seismic waves that nearby homeowners perceive.
The fundamental factor in determining if a well can be impacted by fracturing of rock strata is whether it is within the zone of permanent rock deformation. Extensive research by the U.S. Bureau of Mines (USBM), military agencies, and private consultants has shown that a phenomenon known as cratering is the only important mechanism by which permanent deformation or cracking of the rock can occur as a result of the detonation of explosives.
When an explosive charge is confined in the ground and detonated, the volume of permanently deformed material is ideally cone-shaped. The point of the deformation cone within the rock is at the location of the explosive charge, and the circular opening of the cone is at the ground surface. Studies have shown that the radius of the zone of deformation at the ground surface is no more than one or two times the blast hole depth and that rock outside this zone is undamaged.
This fact is supported by the daily drilling and blasting process at most quarry operations. Blast holes are drilled in a pattern a 6 to 14 ft. apart because the explosive energy is insufficient to fracture the rock at a great distance from each blast hole.
Another concern of nearby homeowners is that ground vibrations produced by blasting could affect the level or movement of groundwater in the aquifer. Studies by Bond (1975), Berger (1980), and Beaver (1984) concluded that there is no significant long-term mechanical changes in the aquifer that could be attributed to blasts detonated at distances greater than 500 ft.
Bond (1975) studied five widely distributed, shallow aquifer sites in eastern Montana using test blasts located 150 to 400 ft. from observation wells. Twenty-five- to 80-lb. charges were placed in the same aquifer as the observation wells. No vibration measurements were made, however, estimated peak particle velocities from these tests would have been 0.50 to 1.1 in./sec. Pumping tests of existing water wells and specially drilled observation wells were performed before and several times after firing a seismic shot.
Bond concluded that any mechanical change in the aquifer structure as a result of seismic shooting should be indicated by change in permeability of the aquifer material. None of the aquifer tests showed any change in aquifer structure.
Berger (1980) studied primarily low-yield (<1 gpm), fractured water table aquifers in Appalachia. Four test sites were chosen based on geographic and geologic diversity. Baseline data on water quality, static water level, and drawdown characteristics were collected on newly constructed wells prior to the advance of a surface mining operation. Ground vibrations at four of the five test sites exceeded 2.0 in/sec. Maximum vibrations ranged from 0.84 to 5.44 in./sec.
Blast vibrations produced no direct evidence of change in water quality or well performance. However, when the pit advanced to within 300 ft. of the wells, lateral stress relief from the removal of downslope support permitted water-bearing fractures to become more open. Static water level dropped and well bore permeability improved because of this additional storage capacity. This stress relief would have occurred whether the support had been removed by blasting or not.
Beaver (1984) studied the effects on sand and lignite aquifers at two sites owned by North American Coal Corp., near Underwood, N.D. The area contains an extensive, poorly indurated sandstone aquifer overlying coal deposits. Pumping tests conducted in the sand and coal aquifer system showed no apparent effect when shots were detonated 1,320 ft. from the pumping wells. Shots 500 ft. from the wells resulted in no permanent effect. Shots located 100 ft. or closer increased the yield from wells finished in the sand aquifer but decreased the yield from the coal aquifer. A shot 50 ft. from the sand production well produced a vertical particle velocity of 2.48 in./sec. Well casings remained intact even after 25-lb. charges were detonated as close as 10 ft. from the well screen.
Well owners often fear that ground vibrations from nearby blasting could possibly crack the casing of their well or damage the pump or other underground components. This concern was echoed by a municipal authority in a study by Straw and Shinko (1994). Ground vibrations due to blasting at a construction project in southern Florida were monitored at deep injection wells used by the City of Pembroke Pines to pump treated waste water into a brackish, artesian aquifer. Vibration measurements were made at the surface and at a depth of 47 ft. The maximum resultant particle velocity reached at the surface was 0.50 in./sec. A reduction in vibration of approximately 50 percent was observed at a depth of 47 ft. Testing prior to and following the blasting operations indicated no change in the well’s pumping ability.
The USBM published a complete study (Siskind et. al., 1994) on the response and damage potential of buried pipelines and vertical wells to blasts at a mining operation. The blasts consisted of multi-hole production shots of 2,000 lb./delay. A total of 31 blasts approached a field of five buried and pressurized pipelines, 6 to 20 in. in diameter; one vertical well; and two buried fiber-optic telephone lines. Peak particle velocities ranged from 0.50 to 25 in./sec at 48 ft. Based on continuous monitoring of pressure, no damages occurred in the four steel and one PVC pipeline. Using the measured vibration, strains, and worst-case theoretical failure for the pipes with their rated tensile strengths, researchers recommended a conservative, safe vibration level of 5.0 in./sec. for horizontal pipelines and vertical wells.
Effects of Mining and Excavation
Blast vibrations do not permanently degrade groundwater quality, but they can sometimes cause local and temporary turbidity that can extend for hundreds of feet beyond a blasted zone. Numerous reports by homeowners tend to substantiate this, although its occurrence is not well documented in the literature.
The material causing turbidity usually consists of fine rock particles, such as silt and clay. Normally, these fine grained particles settle within the secondary openings and even within the well bore itself. As long as the groundwater moves slowly through the voids without turbulence, these sediments remain undisturbed indefinitely, and the water remains clear. But when blasting occurs in the near vicinity, water within the secondary openings can become momentarily turbulent, thus disturbing the fine sediments. Once disturbed and mixed with water, these sediments can remain in physical or colloidal suspension for days or weeks. Fortunately, this problem is only temporary and aesthetic. It is not the result of improper blasting procedures and not suggestive of any physical damage to the aquifer or the well.
Other sources of turbidity can occur at the well, most commonly caused by introduction of surface water into the well system through worn, cracked, corroded, or faulty well seals, fittings, or other well components. Consider turbidity encountered in a groundwater supply system as a warning that the supply could be contaminated by surface water. Excessive bacteria or other organisms can cause turbid or cloudy water.
Turbid water in a well also can be caused by worn well components. A faulty foot valve, for example, can cause water that has been pumped from the well to suddenly come crashing to the bottom of the well, churning up sediments in the bottom of the well. A leaky pipe can cause high pressure water to erode the well bore above the water line and cascade down the well bore.
During Berger’s (1980) study, decreases in the static water level were observed when mining approached within 300 to 400 ft. of operating wells. On sites with sloping terrain, this drop was attributed to a loss of downhill support that allowed existing fractures in the shallow aquifer to become wider. Subsequent testing at a site in relatively flat terrain revealed a similar decline in static water levels after the removal of 70 to 80 ft. of overburden. Overburden removal occurred at distances of 300 ft. or less.
In addition to excavation activity, many mining operations have de-watering wells drilled in and around the pit to create a cone of depression for dry mining conditions. Lowering the water table from de-watering operations or excavation activity can affect nearby wells. At that point, whether a diminished supply or dry well results from blasting or excavation activities is academic. The mine operator may become liable.
Over the years, many states in coal mining areas have promulgated regulations to protect domestic water supplies from degradation due to surface mining operations. The regulations specify which tests are to be completed and are specifically designed to help detect acid mine drainage (AMD).
AMD is created when naturally occurring pyrite in rock oxidizes upon exposure to air and water during excavation (for coal or from any excavation) and forms a solution of iron, sulfate, and acid. Pyrite is abundant in coal-bearing rocks, and once the earth is dug up, AMD may form for many years.
Coal mine operators in Pennsylvania are required to test drinking water and groundwater prior to mining in order to establish a quality baseline for specific chemical parameters. The chemical parameters are those that are likely to change if the water becomes affected by AMD. Tests include pH, conductivity, sulfate, iron, manganese, alkalinity, acidity, and total suspended solids. If water becomes affected by AMD, pH decreases and the sulfate, conductivity, iron, manganese, and total suspended solid contents increase.
| Cited Research and Other Information Sources
American Institute of Professional Geologists. (1983). Ground Water: Issues and Answers, AIPG, Arvada, Colo. |
Part 2 of this article summarizes how quarry operators can help protect against unwarranted damage claims with a pre-blast water well investigation. 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.
Mark M. Smith is division manager, Mine Training Programs for VISTA Training, Inc.
Flexibility is the Key to Success With Superpave
Washing plants enable Missouri producer to meet specification requirements
As the adoption of Superpave gathers momentum across the country, producers have realized specification requirements are tightening. Their answer is to remain flexible in the treatment of their material so it may continue to meet specifications. In particular, producers have discovered it often is necessary to wash their Superpave stone.
Washing of specification material was not really an issue in Superpave’s infancy. But washing of the material is becoming more common because of the additional processing required to obtain the desired product cubicity, which produces additional fines — and deleterious material — during crushing.
“Initially, producers were not washing aggregate used for Superpave material. But gradually, as different states adopt new regulations, producers are discovering it is usually beneficial — and sometimes necessary — that their Superpave material be washed,” said Tim Harms, an application specialist with Yankton, S.D.-based Kolberg-Pioneer, Inc., an Astec company. “For example, in Texas, almost all of the aggregate used for Superpave has had to be washed. Kansas has followed suit. Missouri is working toward that requirement. These state DOTs have found that to get the deleterious material down, the material has to be washed.”
The first full year of Superpave in Missouri was in 1999. Although the Missouri DOT has not begun to require washing of Superpave material, the Central Missouri Division of APAC, a large producer with operations throughout the southeastern and south central United States, recently added sand screws to its quarries producing Superpave material for APAC’s own paving projects.
APAC is a wholly owned subsidiary of Ashland, Inc., which also owns Ashland Chemical, and it is one of the nation’s largest asphalt and concrete paving companies. The company also is a major supplier of construction materials. In addition to paving, repairing, and resurfacing of highways, streets, and airports, APAC performs a number of construction services, including excavation and related work in the construction of bridges and other structures. About 60 percent of the company’s revenues are generated by public sector projects.
“A couple years ago, the Missouri Limestone Producers’ Association reported washing was necessary across the state for Superpave specs,” said Ricky Baker, vice president of APAC Central Missouri Division. “At several of our sites, we were making stone and manufactured fines for Superpave, and we began having to dry-screen and then wash the material with a sand screw as a second process, after stockpiling it. That was when we decided to look into the purchase of a screening and washing plant that we could add to the material flow and make it all part of the same process.” In spring 2001, APAC purchased four Kolberg Model 1822 screening/washing plants for its quarries in central Missouri. Two of these screening/washing plants are skid-mounted, permanent installations, and two are portable.
According to Jeff Wendte, application engineer at Kolberg-Pioneer, the Kolberg Model 1822 screening/washing plant is comprised of a Pioneer 6- x 16-ft. inclined three-deck vibrating screen with a step deck design. The heavy-duty screen operates at a 10° angle. This screen offers a low profile for portability, which factored into two of APAC’s 1822 screening/washing plant purchases. Because of its incline, the screen is well suited for fine screening, and uses less energy to propel the material across the screen cloth. Pioneer inclined screens feature a two-bearing design, and are Huck-bolted together with vibration-proof fasteners. Pioneer screens also feature grease lubrication and adjustable counterweights.
Under the Pioneer screen is a Kolberg 5036-25T Sandprep (twin fine material washer). Wendte said the Kolberg Series 5000 fine material washers used on Series 1800 screening and washing plants feature single inlet plumbing for minimal setup requirements. Standard urethane outer shoes (vs. NiHard) increase wear life and are physically lighter for ease in handling and reduced axle weight on a portable plant. A controlled material entry feed box/baffle plate and rising current manifold work to improve fines separation, and an adjustable drive design minimizes operating costs. The Dodge greaseable lower end flange bearing is a standard bearing, readily available and easily accessed.
“Once we purchased the screening/washing plants and added them to our material flow in these quarries, the whole process became much simpler,” said Baker.
“We chose the Kolberg-Pioneer equipment because we discovered KPI was the only manufacturer we looked at who manufactured all the components for its screening/washing plants. We didn’t want to have to go to different manufacturers with questions or problems. We wanted a single source for our screening/washing equipment. At the same time, we were impressed with KPI’s dealer in our region — Cummings McGowan and West.”
APAC originally installed the Kolberg washing plants at its Branson, Linn Creek, Marshall, and Lanagan quarry sites in central Missouri. The Branson portable plant was moved mid-year 2001 to place an additional screening/washing plant at Linn Creek, and the Marshall portable plant was moved to Rolla, Mo. APAC also recently purchased a portable Pioneer 2500 Ultra-Spec VSI crusher to make the cubical product for Superpave, as well as the necessary fines, because while Missouri produces a lot of stone, it does not offer much natural sand.
“At Linn Creek, we were getting the cubical product we needed, as well as the fines. At the same time, Linn Creek is a high wear application, with a lot of chert,” noted Baker. “We didn’t think the VSI would work as well as the cones we had in that location. But Branson and Rolla did not produce such abrasive material; nor were we getting the fines that we needed, so we have used the Pioneer VSI at both of those locations,” he said.
According to Linn Creek Quarry Foreman Gary Wood, the Linn Creek quarry has probably the most extensive plant flow of APAC’s central Missouri quarries. Linn Creek products include the following:
• 1-1/2 in. – 3/4 in. (Superpave);
• 3/4 in. – 3/8 in.;
• 3/8 in. – 1/8 in.;
• 1/8 in. – manufactured sand (fines); and
• The remainder is washed out.
“With the Kolberg wash plant(s) in place, our plant flow goes from a primary jaw, which we load with a front-end loader, to a scalping screen. We have 2-in. punch plates at the top and 3/4-in. screens on the bottom,” explained Wood. “The overs go to a gyratory cone, and the 3/4 in. x 2 in. go to a surge bin and from there to a finishing cone. From both cones, the material flows to two Duo Vibe screens by Production Engineered Products (PEP — also an Astec company), and the lime is pulled off the PEP screens. Everything that comes off the top goes to the Kolberg 1822 screening/washing plants. The aggregates are washed, and minus 200 fines are removed by the twin screws on the plant. What is retained on the 1 in. screen goes back to the surge bin,” he said.
“The Kolberg-Pioneer equipment has worked well in our setup,” said Wood. “KPI makes a good product, and they stand behind it, along with their dealer. For example, early on, we had trouble with a guard on the far side of the 1822 screening/washing plant; the vibrating was causing it to separate. Dan Doherty (from Cummings McGowan and West) got us another one the next day after we discovered this, and it has been fine ever since.”
Baker agreed. “You’re going to have kinks to work out with new equipment,” he said. “But when the manufacturer and the dealer stand behind the equipment, and fix any problems that arise, it really isn’t an issue.”
Baker said he is pleased, too, that APAC has been able to become its own material source for APAC’s Superpave roadbuilding projects. “We don’t have to worry about going to an outside source for material,” he said. “We are making quality stone at our sites, plus the necessary fines, and we’re able to wash out the deleterious material in order to meet spec. We’re able to use virtually all of our material,which is ideal.”
the bottom line...
Several operations in APAC’s Central Missouri Division chose to re-examine how they were handling washing of material. Rather than dry-screening, stockpiling and then washing the material, the division chose to invest in a screening and washing plant to eliminate double handling and reduce costs.
An Easier Way to Troubleshoot Electrical Systems
Voltmeter leads help locate high-resistance electrical faults without parts swapping
Dan Sullivan, owner of Sullivan Training Solutions, developed TESlite voltmeter leads for troubleshooting electrical problems in heavy equipment.
Editor’s Note: This monthly column is supplied exclusively for AggMan by Association of Equipment Management Professionals (AEMP).
Mechanics looking for a faster, smarter way to troubleshoot electrical systems are following Dan Sullivan’s lead — or, more accurately, his leads.
Sullivan, a 41-year-old, self-employed electrical troubleshooting instructor for the heavy equipment industry, patented an enhanced voltmeter lead system that can turn an eight-hour troubleshooting marathon into a one-hour snap.
The patented TESlite leads plug into any digital voltmeter, making it more accurate in determining where high-resistance electrical faults exist.
Without the enhanced leads, a digital voltmeter’s high sensitivity provides a full, “normal” voltage reading even when loose connections, corrosion, or water interrupts the current flow, said Sullivan.
“My tool eliminates that problem by checking the wiring condition at the load component with the load removed.” said Sullivan.
With a “normal” voltage reading using regular leads, mechanics might decide they need a new motor, a new back-up alarm, or a new solenoid. “The problem is, when you put the new thing in, it still doesn’t work.” said Sullivan.
A digital voltmeter and regular leads might show a voltage of 12.5V. However, the same voltmeter with TESlite leads would show a significantly lower voltage if a resistance fault exists.
Conversely, if the reading stays the same with the enhanced leads turned on, the mechanic can proceed with confidence that the tested wire is not the problem. The primary advantage of the tool is that it quickly confirms whether the wiring is damaged.
Barth Burgett, vice president of maintenance for Ohio-based Kokosing Construction Co., said he has witnessed a marked improvement in the skills of mechanics who attend Sullivan’s Fundamental Electrical Troubleshooting course. Participants receive a set of the TESlite leads.
“Management used to sub out (electrical troubleshooting work) or the mechanics would be swapping out parts,” he said. “We’ve tried to elevate ourselves from parts-exchangers to trying to locate where the problem really is.”
HARNESSING KIRCHOFF
Sullivan developed the enhanced leads in 1999. “In essence, it’s a set of normal voltmeter leads that have been modified to include a simple circuit that allows you to check wires for the presence of corrosion,” he said.
The concept is based on Kirchoff’s Law, which in simple terms, says that total system voltage applied to a circuit must be divided among all resistances in the circuit, and if there is only one resistor or load component in the circuit, it must use up all the voltage.
When Sullivan teaches mechanics how to use voltmeters and how to read wiring diagrams, they leave with a certifiably improved skill level, according to Bill Cyford, equipment superintendent for McLean Contracting Co. in Baltimore.
“You go back and find examples in your daily troubleshooting as a mechanic and these examples he’s giving you and talking about are true,” Cyford said. “He just made your life a lot easier by teaching you a different method to do your job.”
Sullivan’s mechanical career started in 1983 as an aircraft mechanic. He went on to teach aircraft electrical system maintenance and eventually worked to refine the mechanics curricula for the North Carolina community college system.
“The diesel and heavy equipment industries have long been very strong on mechanical things like engines and drive trains, but they were a little behind in the electrical area because the electrical systems were not that complex up until about 10 years ago,” he said. “There was an unavoidable lack of electrical expertise as these systems became more sophisticated and more computerized.”
Supervisors who have hired Sullivan to teach said he quickly establishes a rapport with students. Sullivan said his ability to do so stems from a sincere respect for the job mechanics do and the amount of brainpower the position requires.
The Association of Equipment Management Professionals (AEMP) is an individual membership organization comprised of equipment maintenance and management professionals. Its members are responsible for the purchase, maintenance, employee training, shop facilities, and parts management of leading corporations and government entities that utilize heavy, off-road equipment. Its members also represent the major manufacturers and suppliers of the heavy equipment industry. AEMP provides end users with cutting-edge education, and it is the only organization to offer a certification program for the industry, the Certified Equipment Manager (CEM). For more information, contact Stan Orr, CAE, AEMO executive director, at (970) 384-0510, email at ceo@equipment.org or visit AEMP’s web site at www.equipment.org.
Primary Crushing
By Bob Drake
Aggregates producers today face almost overwhelming options in the design of secondary and tertiary crushing circuits. Advances in wear materials and machine technology are broadening the application of horizontal-shaft (HSI) and vertical-shaft (VSI) impactors in even hard and abrasive material. Flexibility in configuring crushing chambers in impactors and cone crushers is allowing machine customization to better accommodate a greater range of feed characteristics and product requirements. Crusher automation is improving throughput, wear costs, product shape, and gradation consistency.
Ceramics, specialty steels, and carbide-embedded wear parts are changing the capabilities of all types of crushers, but particularly impactors, according to Mark Krause, vice president crushing and screening for Cedarapids. “That is the next real breakthrough that will change how we look at the application of certain machines, especially when it comes to [product] shape requirements,” Krause predicted.
VSI manufacturers are building larger machines to accept up to 12-in. feed in secondary circuits. “The limitation of the VSI crusher in secondary applications had been its capability to handle larger feed material due to the increased mass of the larger particles,” said Scott Rabey, vice president for Impact Service Corp. Larger and heavier impeller shoes and anvils enable VSIs to handle this increased mass, even crushing granite, he said.
Automation is pushing cone crushers to the limit in terms of throughput, wear life, and product quality. Automated, on-the-fly closed-side setting (CSS) adjustment helps maintain consistent product gradation without downtime and lost production. Automated circuits with appropriate surge capacity can keep cone crushers choke fed, which improves product shape and decreases wear costs.
The following products highlight how manufacturers are implementing these features and others and broadening the application of cone, HSI, and VSI crushers.
CONE CRUSHERS
1. JCI Kodiak Series
JCI, an Astec company, released a new series of cone crushers called Kodiak. The 300 and 400 series models are now available; the 500 series is in design. Kodiak cones feature internal balancing, with weights placed out of the way of rock flow, hydraulic thread locking, and anti-friction roller bearings. The hydraulic remote-adjust system and digital CSS indicator provide consistent gradation control without stopping production, according to JCI. Coarse to fine liners can be used without changes to the eccentric, cone, or bowl.
2. Metso GP and HP Cones
Metso Minerals offers the GP and HP series cone crushers for secondary to extra-fine crushing in stationary to mobile applications. Secondary GP-series cones, designed to be compact, can handle up to 16-1/2-in. feed. The same frame structure accommodates several different crushing cavities. The Nordberg A2020 automation unit is standard on most of the nine GP models. The unit keeps the cavity full of material, improves liner utilization, maximizes machine availability, and provides operating data, Metso said. The company’s HP cones have fixed mechanical settings to reduce setting drift and a threaded rotating bowl to maintain a consistent setting around the entire circumference of the crushing chamber. The tramp-release system also has a fixed return point.
3. BL-Pegson 1300 Maxtrak
BL-Pegson, a Terex company, introduced the 1300 Maxtrak. It features a 51-in. track-mounted Automax cone crusher available with a choice of liners for secondary or tertiary applications. The crusher has a taper roller bearing design, hydraulic setting, and tramp release and unblocking system. CSS is adjusted on-the-run using touch-button controls with direct readouts. The 1300 Maxtrak includes a feed hopper with level probes to choke feed the crusher.
4. Sandvik Hydrocone
Sandvik Rock Processing’s 1800 series H- and S-type Hydrocone crushers feature Hydroset hydraulic adjustment and can be equipped with an automatic setting regulation system (ASR). Hydroset allows the mantle mainshaft to drop in order to pass tramp iron and also allows CSS adjustment under full load. Sandvik’s ASR Plus system measures motor power draw and oil pressure in the Hydroset system to adjust the mantle position to maintain a preset CSS or load. The system also can compensate for liner wear, Sandvik said.
5. Telsmith Silver Bullet
Telsmith, an Astec company, developed the Silver Bullet series of cone crushers to improve product cubicity, minimize production of 200-mesh material, and maximize coarse and fine aggregate. The Silver Bullet liner profiles reduce flat and elongated particles in the final product, cut 200-mesh product, and increase the quantity of minus-3/4 in. to plus-8 mesh product, the company said. Silver Bullet series hydraulic systems incorporate a common power package for all functions, including hydraulic relief, chamber clearing, hydraulic lock, dynamic adjust, and anti-spin.
HORIZONTAL-SHAFT IMPACTORS
6. Eagle Crusher UltraMax
Eagle Crusher Co.’s UltraMax line of HSIs comprise six models, with feed openings ranging from the 27 x 32 in. to 69 x 42 in. The machines have solid-steel, three-bar rotors that the manufacturer said reduces wear and provides optimum rotor penetration. UltraChrome titanium blow bars can decrease wear costs to as low as 10¢ per ton, according to Eagle Crusher. UltraMax HSIs have gravity-hung reversible primary curtains made of high-strength manganese, manually adjusted using spindles on the top of the impactor. Secondary curtains have bolt-on replaceable liners and are hydraulically adjustable.
7. Grasan Secondary Plants
Grasan builds road-portable, pit-portable, and stationary secondary plants incorporating Hazemag HSI crushers. Plants are available with diesel or electric power in capacities up to 500 tons per hour. Options include horizontal screens, complete with blending chutes, transfer conveyors, and radial stackers; and manual or computerized control systems.
8. Irock Sidewinder Series
Irock Crushers’ Sidewinder series of secondary crushing and screening plants includes three models with capacities ranging from 250 to 500 tons per hour. The plants include Irock’s “high inertia” HSIs and triple-deck horizontal screens. The impactors have two-bar rotors that the company said allow higher rotating speeds and crushing forces. An increased crusher feed angle increases feed velocity, which promotes more rock-on-rock crushing, according to Irock. An angled discharge chute and impact tray receive material exiting the crusher, increasing wear life of the under-crusher conveyor.
9. Kolberg-Pioneer 4223
Kolberg-Pioneer, an Astec company, designed its 4233 HSI portable plant specifically for crushing RAP, concrete, block, and brick. The crusher’s “sculptured” rotor has the mass of a solid rotor and the clearances of an open design, according to the company. It incorporates heavy-duty shaft and bearing technology from Pioneer’s larger primary impactors. The 4233 plant has a low feed height, a 36- x 30-in. crusher feed opening, and a high discharge height.
10. Lippmann-Milwaukee
The Lippmann 4236LS, 5165LS, and 5196LS are secondary HSIs with rated maximum capacities of 150, 365, and 700 tons per hour, respectively. The crushers feature semi-closed rotors attached to high alloy steel shafts with keyless locking assemblies and four reversible and flippable blow bars. Frame and apron liners are drilled and tapped to use standard hex head cap screws and lock washers. The bolted design keeps the plates tight longer as the liner wears, according to the company.
11. Metso NP Series
Metso Minerals’ NP series HSIs combine a heavy rotor and larger crushing chamber design that improves capacity and product quality and reduces operating and wear costs, the company said. The line of crushers has specific rotors for each type of application and uses identical rotors on the primary and secondary impactors. Hammers are fixed to the rotor by single wedge assemblies. A single hydraulic power unit opens the crusher frame and adjusts the two standard breaker plates. A third breaker plate is optional.
12. BL-Pegson Trakpactor
BL-Pegson, a Terex company, offers a track-mounted closed-circuit plant based on its Trakpactor HSI. The 4242SR is suitable for primary or secondary operations and can process as much as 400 tons per hour, according to Pegson. A 5- x 11-ft. double-deck screen allows production of up to three products or an on-board conveyor can recirculate oversize to the crusher. The unit includes a vibrating two-step grizzly, under-screen and folding side conveyors, and dust-suppression sprays.
13. Sandvik Impactmaster
Sandvik Rock Processing’s Impactmaster S-Series secondary crushers feature eight models with maximum feed sizes ranging from 10 to 16 in. The S-Series crushers share three sizes of rotors with the Impactmaster line of primary HSIs, with diameters of 42.25, 51.25, and 67.25 in. Feed openings of the S-Series crushers range from 31 x 22 in. to 91 x 27.5 in. Two, separately adjustable curtains are mounted on one common pivoting shaft. Retaining rods adjust the gravity-hung curtains. Locking wedges hold the banana-shaped blow bars in place.
14. Stedman Grand Slam
Stedman offers 10 models of secondary HSI crushers in its Grand Slam series. Capacities range from 5 to 700 tons per hour. Grand Slam crushers are available with rotors using two, three, or four blow bars secured with a wedge locking mechanism. The two aprons have interchangeable, 3-in.-thick tapered, high-chrome liners. Side liners come in three shapes and are interchangeable from model to model. An optional variable-speed drive allows on-the-fly gradation changes, Stedman said.
15. Telsmith
Telsmith, an Astec company, manufactures seven sizes of secondary HSI crushers with capacities ranging from 80 to 660 tons per hour. The crushers feature high-chrome hammers and two, independently adjustable aprons.
VERTICAL-SHAFT IMPACTORS
16. Canica Crusher VSI
Canica Crusher, a Terex company, offers nine VSI models with maximum feed size ranging from 1.5 to 12 in., rated capacities from 50 to 1,000 tons per hour, and tub diameters ranging from 50 to 125.5 in. The crushers are available with enclosed rotors or open shoe (impeller) tables. Table options include three to six impellers on different models. Canica’s VSIs can be equipped with anvil ring assemblies or rock boxes. A vibration detector provides a warning or machine shut off if vibration exceeds preset limits.
17. Cemco Turbo 175
Cemco added the Turbo 175 to its existing line of six VSI crushers. The Turbo 175 accepts up to 7-in. limestone feed at 1,200 tons per hour, according to the company. One Turbo 175 has replaced two 7-ft. cone crushers in one application, Cemco said. Cemco’s VSIs are available with open shoe tables or SuperChipper rotors; anvil rings or autogenous rock boxes. The anvil ring can be adjusted up or down in the tub to accomodate wear patterns.
18. ISC Secondary VSIs
Impact Service Corp.’s (ISC’s) Model 103 VSI accepts up to 8-in. feed; its Model 130 accepts up to 12-in. feed. Both machines have larger and heavier impeller shoes and anvils for application in secondary crushing circuits, ISC said. Impeller tables are available in three- to six-shoe designs. A California granite quarry uses a Model 130 as a secondary crusher accepting 10- to 12-in. feed at 900 to 965 tons per hour, according to ISC. Two Model 103 VSIs make up the tertiary circuit, each processing 550 to 600 tons per hour.
19. Kolberg-Pioneer Ultra-Spec
Kolberg-Pioneer, an Astec company, expanded its Ultra-Spec line of VSIs to three models: the 1500 and 4500 join the existing 2500. Maximum throughputs for the 1500, 2500, and 4500 are 150, 275, and 450 tons per hour, respectively, according to the manufacturer. All three models are available in standard, semi-autogenous, or fully autogenous configurations. Kolberg-Pioneer said its new flow-through rotor design allows for higher capacity with less horsepower required per ton per hour.
20. Metso Barmac
Integrating Nordberg’s and Svedala’s VSI crusher lines, Metso Minerals rebranded the autogenous Barmac Duopactor as the Nordberg Barmac B-Series, joining the Nordberg Barmac VI-Series. It is available in seven models. A VSI Operational Control System (VOCS) monitors vibration and crusher bearing and motor winding temperatures. Another system, Automatic Crusher Regulations (ACR), continuously adjusts the crusher to maintain optimal conditions, Metso said. The VI-Series VSI, available in four models, has a shoe and anvil or rotor and anvil design. It has automatic lubrication, an articulated motor base to ease drive pulley changes, and an air-recirculation system to control dust.