"The grinding action of the integrated hydraulic rotary cutter produces a precise, smooth-walled trench that does not require over excavation, as is the case with hammer trenching where the deeper the trench, the wider the opening (i.e., V-shaped trench cross-section)," says Kogelmann. "Additionally, grinders produce a finer, more uniform material compared to large rock pieces generated by hammering. Typically, the cuttings can be used as backfill or pipe bedding, thus eliminating the need for removal of the material from the jobsite and costly disposal or secondary crushing."
He adds, "The crushing ability of the Alpine cutter crusher bucket permits re-sizing of material via an adjustable crusher plate."
The bucket uses the same motor, transmission and cutting tools as standalone cutter heads, so the cutting performance is the same in terms of shaft torque and cutting force. "The cutter-crusher bucket is more productive where material handling is required, and when there is mixed ground where both conventional bucket excavation and rock grinding are needed," says Kogelmann.
Shaft excavation is also simplified. According to Kogelmann, "In shaft excavation jobs where an excavator can be utilized, the cutter bucket is highly efficient due to its ability to both cut and load. For instance, if a hoist bucket is being used to cut material from the shaft bottom, the cutter bucket is used to load the hoist bucket. Before the cutter bucket, contractors had to either swap attachments or use a second machine for mucking, which increases time, equipment needs and labor."