entry may involve the practice of rock shaving. For shaving, holes are drilled in the rock, filled with a small amount of gunpowder, and then set off to spall the rock off in thin layers. A similar technique, called plug and feather, involves driving wedges into lines of small diameter holes that have been drilled in the rock. As the wedges are driven into the holes, a crack forms along the line of holes and the rock is eventually broken. A more recently developed technique is known as "capping", where a hole is drilled into the rock using a battery-powered drill, a small charge (commonly designed for use with a nail gun) is inserted, and tapped with a long steel rod in order to cleave off pieces of rock. An environmental and safety assessment should be conducted before blasting to ensure minimal impact to the cave environment. References Caving