The method utilizes the proprietary and patent protected Controlled Foam Injection (CFI) technique to fracture rock and concrete. The use of high-pressure foam as the fracturing medium completely eliminates the airblast, flyrock and toxic fume problems associated with explosive based techniques. The CFI method may be used in very close proximity to personnel, sensitive structures or equipment. The controlled breakage characteristic of the CFI method allows for rock removal to very precise dimensions with minimal damage to the remaining rock. All the process byproducts are environmentally benign and completely biodegradable.
The CFI method is based upon the use of high-pressure foam to initiate, pressurize and propagate controlled fracturing in rock and concrete.
An injection barrel, incorporating a proprietary hole-bottom seal, is used to inject high-pressure foam into the bottom of a pre-drilled hole in the rock or concrete to be broken as indicated in the animation at right.
The high viscosity of the foam (as compared to a gas) combined with its stored energy characteristics (as compared to a liquid) result in very controlled and efficient breakage.
The foam pressures required to break rock or concrete are significantly less than required in explosive or propellant based methods.
Consequently, airblast and flyrock are reduced to very benign levels, allowing the method to be applied in a continuous manner and to be used in urban and other sensitive environments.
The hardware for the CFI fracture of rock or concrete may be readily mounted on a conventional articulated boom for application to excavation and/or demolition operations. A percussive drill may be incorporated on the same boom carrying the CFI hardware so that hole drilling, indexing for injection barrel placement and breakage can be carried out in a systematic and automatic manner.
Following the initial technical development realized on SBIR (Small-Business Innovation Research) programs funded by the National Science Foundation, the CFI technology has been refined and improved in several aspects. The ability of the method to fracture and excavate both hard massive rock and highly fissured rock has been significantly improved. These improvements have also reduced even further the air blast and fly rock of CFI breakage. CFI systems with these improvements have been integrated with both small drilling units manufactured by Ripamonti SaS in Italy and with conventional hydraulic excavators. These machines have been tested and demonstrated on small projects and are now available for dedicated commercial projects.
The CFI method is well suited for automation. The flexibility of the method (in terms of hole depth and foam pressure, quality and viscosity) allows it to be tailored to rapidly changing ground conditions or a variety of breakage conditions. The benign nature of the airblast and flyrock of the CFI fracturing method allows drilling, breakage, mucking, ground support and haulage equipment to remain at the working point or face during rock excavation operations.
The CFI method is ideally suited for any excavation or breakage situation where conventional explosive methods are precluded, whether for environmental, legal or public concern reasons.
The proprietary foam-based CFI method can be used in a broad variety of specialty drilling and excavation situations. The method is ideally suited for the demolition of oversized boulders encountered in both construction and mining operations.
The CFI method can be used to develop trenches for utility or pipe lines or caisson shafts for bridges and power line towers. The method can be used to excavate utility tunnels under existing streets and buildings, to provide access tunnels or shafts to existing subway systems, or to create or enlarge underground space for buildings.
In underground mining operations, the CFI method can be used for selective mining or for mine development in unstable ground. As the method imparts negligible damage to the remaining rock, the need for ground support can be significantly reduced.
The CFI method is useful for demolishing or stripping concrete structures when explosive methods are precluded or where salvage and recycling of building or structure components are desirable. As the method causes no damage to remaining concrete, repairs to concrete structures may be made efficiently and economically.
For additional details on the development and commercialization of the CFI method or to discuss specific applications please contact:
Chapman Young
Applied Geodynamics, Inc.
P. O. Box 772129
Steamboat Springs, CO 80477
Phone: (970) 879-3032
E-mail: cfi@capprex.com
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