The Stemlock Gas Bag is a self inflating borehole plug that is used to block or seal a hole at any depth.
They are made for 11" to 13" diameter holes. Heavy Duty gas bags are for very heavy loads that will be supported for a long time. There is no need for an air compressor, for the bags self inflate chemically. There is no leakage because the Gas Bag is sealed during the manufacturing process.
There is no heat produced during inflation and the ingredients are not carcinogenic.
Substantial savings of up to 35% in explosives costs can be made by using the Gas Bag for air column blasting techniques.
How to Use a Gas Bag
Gas Bags come pre-folded for ease of handling. They are held together by tape or rubber bands. Do not remove these because they allow the Gas Bag to inflate properly. Attach a cord to the tag at the top so that the Bag can be lowered to the correct depth in the hole. In the case of the vinegar Gas Bag, squeeze the colored liquid container and pop it. This releases the vinegar onto the sodium bicarbonate. Make sure all the vinegar has drained onto the bicarb pouch then lower in the hole. You have about 40 seconds to get the Bag in place before inflation starts. When the Bag is tight in the hole, remove the cord with a sharp tug.
The aerosol version works by locking down the activator cap on top of the can. Push hard enough to make sure the valve tab is locked down. This releases a colored liquid for about 40 seconds of delay time before inflation starts. Again, give the cord a sharp tug to retrieve it once the Bag is tight in the hole.
Pre-Splitting
Hole spacing should be 15 to 24 times the borehole diameter in inches depending on the local geology. A good example for many coal highwalls is 18 foot spacing for a 10-5/8" hole.
Use Less Explosives
Save 15% to 35% of the total explosive load and still have excellent dig-ability. It's possible to reduce vibration and noise in addition to cost savings.
Substitute for ANFO and Emulsion Blends
If your holes have only a few feet of water, try dropping a Gas Bag on the water to seal off the hole. Add a little stemming and use ANFO instead of waterproof explosives. Generally you can use this system up to 8 times the borehole diameter of water.
Plug Cavity
Plug holes in Vertical Crater Retreat mine methods
