A new device can split large boulders or blocks of concrete without the flyrock and noise produced by explosives. The Boulder Buster (Figure 1) was developed in South Africa by the Swartklip Corporation. It uses a cartridge resembling a shotgun shell and a column of liquid to generate a high-impulse pressure wave. The pressure wave fractures the surrounding structure. The Boulder Buster can break boulders larger than 2 meters in diameter and rock walls in 2-meter lifts. Yet it is not rated as an explosive, and certification and training are minimal. In addition, the Boulder Buster has no special storage or transportation requirements.
The Boulder Buster is primarily a firing mechanism mounted on a flat plate with a 9-inch barrel extending below the plate. (Figures 2 through 12 depict the preparation for firing.)
[Click to skip pictures.]
Figure 2-A hole is drilled
in the boulder using a portable drill.
Figure 3-Water is poured into the hole.
Figure 4-A booster cartridge
is dropped in the hole.
Figure 5-The impulse barrel and breech
block assembly is placed in the hole.
Figure 6-The blast mat is
placed over the breech block.
Figure 7-The "primer" cartridge
is placed in the breech block.
Figure 8-The primer cartridge
seated in the breech block.
Figure 9-The firing mechanism
is threaded into the breech block.
Figure 10-The lanyard is attached
to the firing mechanism.
Figure 11-The lanyard is pulled
to fire the primer cartridge.
Figure 12-Results of using the Boulder Buster.
A hole is drilled in the rock or other structure and water or a gel is poured into the hole. The Boulder Buster is placed on the structure's surface with the barrel inserted into the liquid-filled hole. A mat is placed over the device and the Boulder Buster cartridge is chambered in the breech. After the firing mechanism has been screwed into the breech, the operator attaches a lanyard to the pull ring. The operator moves to a safe position 25 meters away and detonates the cartridge by pulling the lanyard.
During Fiscal Year 1997, MTDC worked with the Umpqua and Idaho Panhandle National Forests in field testing the Boulder Buster. In 1998, Jim Tour, the Explosives Project Leader at MTDC, used it to help Northern Region engineers with the emergency removal of a dam spillway on the Bitterroot National Forest in Montana. The tests of this device have been impressive. They show the Boulder Buster to be a safe, cost-effective substitute for explosives when rocks need to be broken.
This tool can be used safely relatively close to equipment and personnel. It can be used during periods of high fire danger without the risk of starting secondary fires.