Pit & Quarry, February 2019
DRILLING BLASTING action that should be long enough in time to permit their performing the necessary work before rock movement and stemming ejection can occur Ash stated Even back then with confusion on the role of shockwaves in blasting Ash observed how critical it was for stemming to properly confine explosive gasses The actual effect of stemming is not in changing the way that the explosive functions but in increasing the efficiency of using explosives in a borehole by partially sealing it The stemming should hold not only until the rock is fractured but until face movement begins and the borehole is naturally depressurized through the fractures in the rock Today it is understood that crushed gravel is the preferred material for stemming as it provides both internal stresses where bridging of the material occurs It also creates a plug that has shear strength providing resistance from blowout Drill cuttings water concrete plaster and other methods are not preferred because they lack these properties and are considered inadequate stemming Stemming plugs on the market today can improve the performance of drill cuttings but they do not compare to the use of crushed gravel alone IMPROVE RELIABILITY AND PRODUCTION WITH OUR CRUSHERS US Representative Michael Tougher michael tougher@ seprosystems com Phone 15419442962 Toll Free 18009905568 GRIZZLY KING JAW CRUSHER CONE CRUSHER MINERAL PROCESSING AGGREGATE SPECIALISTS Visit seprosystems com pit quarry for more information GRIZZLY KING JAW CRUSHERS CONE CRUSHERS DEWATERING SCREENS VIBRATING GRIZZLY FEEDERS AND MORE 66 PIT QUARRY February 2019 pitandquarry com ISTOCK COM KOER A variety of factors can contribute to a poor blast A low bench for example will blast poorly compared to a high bench But as Richard Ash noted decades ago the bench length should never be less than the burden dimension
You must have JavaScript enabled to view digital editions.
