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Rock Grinder Proves Faster Than Hammering In Chicago.  Who? What? Why?

Posted by Mike Booth & Chip Kogelmann

May 31, 2022 6:16:42 PM

Scott Russ had seen Rockwheel drum-style cutters at trade shows and online, but he was unconvinced they could do more than the hydraulic hammers typically employed. J Russ and Company is a forward thinking, full-service site civil contractor who has been working in the Chicagoland area since 1979. From their Lockport, IL headquarters they specialize in mass grading, excavation, site utilities and ground stabilization. 

Scott contacted Rockwheel Americas (Bellefonte, PA), to learn more. While reviewing the job demands and available excavators with the Rockwheel team, it was determined that he needed a high power, aggressive Rockwheel for their Caterpillar 352 Next Gen (55t). Because Rockwheel Americas offers rent-purchase-option (RPO), he decided to rent the monster 300hp G60 twin drum Rockwheel to go after the notoriously challenging limestone in the Joliet, IL area which can reach into the 20,000+ psi compressive strength range. The Rockwheel G60 is the only model in its class with gear reduction boasting up to 47,300 ft lb of torque and nearly 40,000 lbs of pick force, so it offered an opportunity to directly assess rock grinding vs. impact hammering. The job, trenching in rock for the installation of sanitary sewer 3-10 feet deep, was already a handful for the 14,000 ft. lb. hammer which was not meeting their production requirements, so why not take a chance on the newer method.

 Rock grinders have conical carbide teeth installed at a 45° angle which attacks the rock differently than a hammer. This angle of attack goes after the tensile and shear strength of the rock which is much lower (~10-15% of compressive strength) than the compressive strength which a hammers attack. This is a result of the microscopic structure of rock: it contains microscopic cracks which are forced open and enlarged by tension and shear but which are forced closed by compression. (https://en.wikibooks.org/wiki/Historical_Geology/Physical_properties_of_rocks)

 tension compression shear  

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With approximately 60 teeth (depending on specific model) rotating continuously at a typical 60-65 rpm with very high torque, there can be 3000-4000 “bites” per minute. So, although an individual “bite” may not seem significant, the cumulative effect is remarkable! This also explains how a crushed stone product results from the grinding action and frequently this stone is reused onsite rather than hauled away as is the case with hammered rock.

 

On the job site, the result exceeded expectations with the Rockwheel G60 generating two major benefits: a significant increase in production compared to the hammer and the ability to reuse the 2-3 inch backfill created by the grinding process. Moreover, as the photos make clear, the precision of cut and absence of overbreak mean no unnecessary excavation was done.   He was very pleased with the G60 and may soon be adding another Rockwheel for a 40-ton excavator as the work of J Russ and Company expands. The RPO was a low risk path to proving the effectiveness of the rock grinding approach. It allowed use of the tool for an extended period on an active job with their own equipment and operators with the option, but not obligation, of converting to a purchase.

 G60 Rockwheel Trenching

Cuttings from Rock Grinding

 

When it comes to the Rockwheel drum cutters, as more units are successfully deployed nationwide, it’s hard to deny their advantages over hammers for many applications, especially rock trenching. From trenching to foundations, concrete removal to general rock excavation and beyond, Rockwheel offers a faster, higher precision, quieter, and more effective solution. Rockwheel Americas has a national rental fleet, complete inventory of units and parts, nationwide service support and the most experienced team in the business.
For more information visit www.RockwheelAmericas.com or contact direct at tel. 814-466-7134 or email
info@alpinecutters.com.

 

 

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Topics: Trenching, rock grinder, rock trenching, drum cutter, rock cutting

Precise Cutting of Shale Cap Rock in Western Pennsylvania, USA

Posted by Chip Kogelmann

Jan 9, 2021 12:52:28 PM

A Western Pennsylvania mineral products company had a problem.  In some locations, overlying their valuable deposits of calcium carbonate limestone was a layer of shale rock that, when mixed with the underlying material during blasting, hauling & crushing operations, contaminated and devalued the end product.  Their high-calcium crushed aggregate and pulverized products have many uses in agriculture, sulfur capture, metal production, cement and asphalt, and other industries. To meet the rigorous chemistry requirements contamination of the product must be minimized. How to precisely remove 1-2 foot strata rapidly?

D30 Rockwheel Drumcutter

It started with a call to Alpine-Rockwheel Americas to arrange a site visit to evaluate the suitability of the Rockwheel drum cutter rock grinding attachment for this application. While we are careful never to over-promise as our competitors are apt to do, it was clear this was a good fit.   A CAT 320D already onsite was selected as the carrier machine. It’s important that the carrier excavator has the power, weight, and hydraulic capacity to optimally run the Rockwheel drumcutter. Alpine personnel selected a D30 (150-hp) twin drum Rockwheel cutter for the job and following a short 1-day demonstration to prove the concept the unit was put to work in earnest. The result was beyond satisfactory. Operators were able to accurately grind the unwanted rock shelf and cleanly expose the underlying material. The cuttings from the rock grinding process were loaded out and the smooth surface made for easy access for drills for the next round of production.

The continuous nature of grinding rock with an excavator mounted Rockwheel drum cutter far exceeded what a hammer could do in this application. The Rockwheel drumcutter attachment gives and excavator the capabilities of a continuous miner.

While the main uses of the Rockwheel cutterheads are in trenching, foundations, concrete removal, and general rock excavation this job makes clear the versatility of high torque drum cutters.   How can you imagine using this versatile tool? Stump grinding? Cutting frozen ground? Dredging? Wine Caves? Scaling and profiling rock faces? Please leave a comment below to let us know your ideas!

With a national rental fleet, massive inventory, nationwide service, growing dealer network, and the most experienced team in the business, we at Alpine-Rockwheel Americas are ready to roll up our sleeves and work with you. Dealer inquiries are especially encouraged! www.alpinecutters.com | 814-466-7134 | info@alpinecutters.com

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Topics: Rockwheel, rock grinder, drum cutter, rock cutting

Disturbance free rock cutting adjacent to existing foundation...Rockwheel drum cutters get the job done

Posted by Chip Kogelmann

Jun 1, 2018 11:39:36 AM

With the economy on steroids this year there is tremendous construction activity all over the United States.  Washington, DC is no exception and we're seeing constant renewal where outdated buildings are giving way to new construction.  This means demolition and foundation work in close proximity to existing structures.  Care must be taken and disturbance minimized when working within inches (literally) of existing buildings which are occupied, functioning workplaces or residences.   

Rockwheel excavator mounted rock cutting attachments (sometimes called drumcutters or cutterheads) are an ideal tool when both accuracy and productivity must be achieved simultaneously.  In this case, a limestone bedrock foundation needed to be deepened immediately adjacent to an adjoining building footer.  To avoid the risk of damage to the neighboring structure hydraulic hammers were not an option because of shock waves and vibrations that would be reverberate through the rock mass and concrete.  This can result in cracks and unseen microfractures that weaken the foundation.

Clean 2-hose connection makes installation simple      Simple 2-hose system speeds up installation .  Note helix scroll on cutting drums

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                        Attack angle of picks shears rock , allows smoother cutting and makes reusable cuttings

 

Rock grinding attachments attack the rock in a very different manner than hydraulic hammers.  Unlike hammers (i.e. breakers), which go after the unconfined compressive strength (UCS) of the rock, the shearing action of the rotating conical carbide picks (teeth) exploits the tensile strength of the rock which is 10%-15% of the UCS.  By "raking" the rock at 45-50 deg. attack angle an added benefit is creation of smaller rock fragments and these cuttings can often be used onsite as backfill without crushing.  This mechanical rock cutting or grinding results in significantly lower seismic disturbance which means safer rock excavation when close to buildings or other sensitive infrastructure such as gas lines.  Moreover, the degree of precision of rock or concrete cutting is exceptional.  Rapid and Precise are two words frequently used to describe the cutting action of the Rockwheel drum cutters.  Compared to other rock grinding attachments on the market the Rockwheel rock and concrete grinders have a optimal layout of teeth on the drums which results in a smooth cutting action.  This means less frequent stalling of the cutterhead, more continuous rock cutting and ultimately more CY/hr (m3/hr).  For exceptionally hard material when pick penetration is hampered a demolition drum can be used which features a helical depth limiter which prevents the tool from try to take too big of a "bite".  This less aggressive drum decreases vibrations and stalling of the cutterhead which means the Rockwheel is cutting rock a greater percentage of the time.

So...the next time you're faced with rock on concrete removal in a sensitive site where collateral damage is unacceptable give the experts at Rockwheel Americas a call.  We'll gladly work with your local excavator dealer to ensure optimal hydraulic set up for peak performance of the rock cutting attachment.  We have a national rental fleet and gladly work either customer direct or through your local equipment dealer.  We maintain an extensive inventory so units can be delivery typically in less than 1-week.  Rent, Purchase, or RPO (rental purchase option)...your call.  Dealers, we're always looking to building new relationships so call about our demonstration and consignment program.  www.alpinecutters.com 

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Topics: Concrete Grinding, Rockwheel, drumcutter, rock grinder, drum cutter, Antraquip, rock cutting

About this blog

This blog is a resource for research, how-to's, and general news regarding rock grinders, transverse cutter heads, roadheaders, and alternatives to hydraulic hammers. 

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