Quarries are an essential part of the rock and minerals people use and need for all sorts of applications. Visiting a quarry with your class is a fun and informative way to examine rocks, study geological formations, and learn about how a quarry is made. Drilling and blasting are two essential processes to creating different areas in the quarry. While you cannot be present during a blasting process, you can request a viewing of the drilling process and what the drill holes look like and are used for. Then you can use the following step-by-step look at how new sections of quarries are made and build off what you saw on the field trip to the quarry.
Drill Holes Are Blast Holes
Drill holes are meant to weaken areas of rock. While this helps to loosen some rock in the quarry walls, it cannot shake an entire face of wall or get through a large chunk in little time. That is where the blasting comes in. After a series of carefully plotted and planned drill holes are completed, the blasting company inserts explosives into these drill holes (way back when it was sticks of dynamite; now it is bits of C4 with blasting charges).
The Charges Are Activated for an Explosion
The blasting charges, or caps as they are sometimes called, provide the vibration waves needed to activate the C4. Fire and/or heat is also necessary and is provided simultaneously with the blasting cap vibrations to cause the explosion. You can create blasting caps for a science experiment in your classroom, but C4 is off-limits. A little gun powder in a controlled outdoor demonstration using a rocket helps the students understand how blasting caps work.
The Rubble from the Explosion Is Cleared Away
After the blasting charges have all been activated, and the demolition expert has verified that every last blasting cap and bit of C4 has been detonated, the quarry's crew can swoop in and clear away the rubble. No one can enter the blast zone before the licensed demolition expert has verified that everything that was supposed to explode has. Otherwise there could be some very serious injuries and fatalities if there is a delayed explosion or a construction truck accidentally activates a missing explosive.
The rock rubble is picked through to see if there is anything valuable within the blasted rock, and then the rest is sent on to a rock refinery where it is broken down further to make various rock products, like gravel, for construction. Using a hammer, some rocks, a magnifying glass and a rock tumbler in your classroom, you can show your students how this end process in the quarry works.
For more information, talk with a company like 3 - Rivers, Inc., Drilling & Blasting.