At many mining projects around the world, workers are often troubled by water that is encountered in their blasting operations. These actions need an efficient and inexpensive method to remove troublesome water from blast holes prior to loading explosives. Without dewatering, wet conditions require the use of expensive explosives cartridges, or other products need to be tried that do not necessarily break the rock properly. When the mine operators can efficiently dewater, they can choose the most effective explosives products and techniques for the specific material that needs blasting.
The Pneumatic Blast Hole Dewatering System was originally developed and perfected for blasting operations occurring along the wet northwest coast of North America. Since its inception, the system has found enthusiastic users in all corners of the world.
This effective and inexpensive device, is available in a range of sizes that will quickly remove water from holes from as small as 63mm in diameter, through holes in the 178mm range, to depths approaching 30m.
The simple system consists of two hoses: one for air supply and the other for water discharge. The hoses are fixed to a stainless-steel body assembly. An expandable rubber sleeve is attached to the body which has a two-meter-long intake fixture connected at its lower end.
In use, the entire lightweight body and sleeve assembly, with the intake hose section suspended below, is lowered into the blast hole to the water level. Compressed air is used to inflate the flexible rubber sleeve, thereby expanding it to form a seal against the inside diameter of the drill hole. A nylon valve at the bottom of the sleeve then automatically diverts pressurized air into the sealed portion of the hole which has been created below the sleeve. This pressure displaces and forces the water down to the point of the intake line, then up through the center of the pump body, and on out the discharge hose to the surface. After the two meters of water below the sleeve is removed in a matter of seconds, the air valve is closed, the pump is lowered, and the process is repeated. When all the water is removed from the drill hole, the pump assembly is withdrawn. The dewatered hole can then be primed and loaded with the appropriate explosives.
A small compressor that makes 15 CFM at 100 PSI will be more than adequate to generate air for the system. A pressure regulator-valve assembly is furnished. Normal operating pressure is about 50 PSI. Many customers use the standard compressor that furnishes air for the brake system of their bulk truck to supply air pressure for this purpose. More information and pricing can be found on the net at www.bds-usa.com.
