Having a ‘blast’ among the rocks

DPA

Just before the explosion, a warning signal sounds; a few seconds later Bernd Sauter presses the button marked “fire” and thousands of tons of rock come crashing down. Sauter works at a quarry belonging to a construction materials company, HeidelbergCement, and several times a month he gets to explode cliffs of limestone to be made into cement.
“It’s a lot of fun, although it’s a big responsibility. Especially when we have visitors who come to watch,” says the 40-year-old. In order to qualify as a explosives man or woman, you need to have some kind of relevant tradesman’s qualification and complete a 14-day course.
A trained industrial mechanic, Sauter got his certification in 2004 and blowing things with a mighty blast has become routine for him. “Rushing this is dangerous. You have to be careful,” says Sauter. He takes note of how everything is going as he gets the blast holes ready.
The first time he carried out a detonation, he wasn’t so relaxed. “I was pretty nervous. I’d been present at a few previously. But when it’s your responsibility for the first time, it’s a bit different,” he says. When asked if his wife worries about him because of his job, he shakes his head: “She trusts me.”
It’s like everything, according to the German Demolition Association – if you know what you’re doing, industrial explosives are very safe. “Of course there’s always a risk with every explosive,” says the association’s deputy chair, Manfred Dax. “That’s why you need the necessary expertise.”
If too much explosive is used, for example, chunks of stone could end up flying through the air and hitting people. It’s also important to make sure all of the explosive ignites and that none remains in the ground.
Accidents do happen, says Dax,
but they’re rare. Regulations governing the storage of explosives are also very strict — explosives and detonators cannot be stored together and not a single gram of explosive can leave storage without the proper paperwork.
Painstaking preparation work goes into blasting rock; in every hole drilled — the holes are around 30 metres deep and must be four metres apart — 140 kilograms of explosives is placed. The number of holes depends on the size of the rock formation being brought down as rubble. On average around 15 are needed.
The explosives are pink and harmless looking, but are enormously powerful in combination with the detonator and fuse. To dull the sound of the explosion somewhat, the ends of the holes are filled with a few metres of rock.
Finally, the detonators leading to each hole have to be electrically connected with one another so go off at the same instant. Just before each big day, Souter gets several colleagues to help him with final preparation. And then: BOOM!
In his opinion, the quarry at Nussbaum, south-west Germany, is a fairly agreeable place to work. The demolitions are usually pretty similar and predictable, since the stone here is homogeneous. This will not be a job for life, as some day the quarry will be exhausted and HeidelbergCement will have to look elsewhere for rock to charge its kilns.
“We assume that in eight to
twelve years it’ll have no more blastable limestone left for cement production,” a HeidelbergCement spokeswoman says.