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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


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


                        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 










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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