Mining Weekly

A South African-developed blasting technology is finding growing acceptance in South America.

The Boulder Buster, which is said to offer a safe and pollution-free alternative to dynamite and other explosive compounds, has been introduced to the South American market throught the Sao Paulo office of the Gauteng Economic Development Agency (Geda) and Sultech Corporation.

Manufactured by Swartklip Products, a commercial subsidiary of Denel, the technology makes use of water's natural conductive properties to create and transmit a pressure pulse in a procedure called hydro-fracturing.

Hydro-fracturing has proved to be a safer and less intrusive method of breaking rock than conventional blasting, due to low concussion and noise generated. The machine is safe to operate from a distance of 7 m.

Civil applications of the Boulder Buster include the laying of pipelines, widening of existing roads, general construction and demolition.

Mining and crushing operations can also benefit from the machine, as it can be used on-site to break up outsize rocks before they have the opportunity to jam the crusher, preventing expensive halts to the operation.

The need for secondary rock-breaking on mines and in crushing and screening operations has led to the development of a larger, mechanised version of the Boulder Buster, called Ro-bust.

Ro-bust is capable of drilling, loading and breaking ten cubic metres of rock in three minutes.

Conventional rock breaking technology requires a hole to be drilled into the boulder, which is then filled with explosives. Once detonated, the explosives cause a build up of pressure, and the rock, unable to withstand this force, shatters explosively, scattering debris in all directions.

The Boulder Buster also requires a hole to be drilled into the rock, but then the hole is filled with water and the Boulder Buster is inserted into the opening.

A cartridge similar to a 'blank' shotgun cartridge is loaded and detonated.

The resultant short, sharp energy pulse is efficiently transmitted via the water into the heart of the boulder, causing it to resonate.

This resonance causes the boulder to fracture along its inherent fault lines and literally fall apart, with little or no scatter, minimal concussion and almost zero toxic gas.