FC115 Focal Charges are
designed for secondary rock breakage. A FC115 is more efficient than an equivalent mass plaster charge, and does not require mud-capping. A FC115 may be rapidly deployed as it does not require any holes to be drilled in the target boulder.
A FC115 comprises nominally 1000g of high explosive cast into a moulded plastic form that defines a steep angle focal cavity. A detonating cord tail is cast into the form to permit initiation by either detonators or detonating cord. The cord tail also enables multiple units, in relatively close proximity, to be tied into a detonating cord harness.
When detonated, the FC115 focuses the detonation energy along the cavity axis. A stream of hot, high shock, gases are directed into the rock target that the charge is in contact with, shattering the target.