TECHNOLOGY DESCRIPTION -

The method utilizes a proprietary Controlled Foam Injection (CFI) technique to fracture rock and concrete. The use of high-pressure foam as the fracturing medium has been shown to reduce significantly 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 allows for very precise rock removal.
   

• The process byproducts are environmentally benign and biodegradable.
   

• The controlled fracturing allows for the efficient and controlled stripping of concrete from reinforcing steel.
   

• The method is ideally suited for any excavation or breakage situation where conventional explosive methods are precluded.
   

• Compared to explosive breakage, CFI breakage requires less than one fifth the energy expenditure.
   

• Compared to mechanical methods, such as impact hammers, rock cutters and splitters, the CFI method provides much higher excavation rates.
   

• Lower energy requirement, up to 90 percent less, results in smaller, lighter, more mobile, and less expensive equipment.

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 substrate to be broken. The high viscosity of the foam combined with its stored energy 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 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 so that hole drilling, indexing for injection barrel placement and breakage can be carried out in a systematic and automatic manner. The CFI method is well suited for automation. The flexibility of the method 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 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. 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 remaining rock, the need for ground support can be significantly reduced. In surface mining and excavation operations, the CFI method offers several advantages vis-à-vis explosive and mechanical methods.

The CFI method can be used to:

• Develop trenches for utility or pipe lines
   

• Excavate caisson shafts for bridges or power line towers
   

• Excavate utility tunnels under existing streets and buildings
   

• Provide access tunnels or shafts to existing subway systems
   

• Create or enlarge underground space for buildings.

This technology has been developed by Chapman Young, President, Applied Geodynamics, Inc., PO Box 2129, Steamboat Springs, CO 80477, 970-879-3032

REFERENCES

EQUIPMENT

KOMATSU

TDM 750