Day 4 - Quarry day

Day 4 – Friday, July 1^st, 2011

Happy Canada everyone! To celebrate, we went to the docks and bought 2 bags of fresh, wild mussels and cooked them in wine + garlic + parsley. Yum!

We spent a somewhat frustrating day today looking at the Stålaker, Hakestad, Malerod and Vardeasen quarries. Frustrating because we didn’t find many pegmatites so no interesting minerals. We did find a few samples at both Hakestad and Malerod, but nothing special and we won’t know for sure until we get back to CMN and check them out under the microscope and by XRD. As I learned when I was an undergrad, white sprays and balls are good things, so take all those home. All the ones we found are 0.1-0.5 mm in size, so maybe interesting. It’s been raining here for the last 2 days so the quarries are mudbogs. Our rental car is filthy! The powder that is created by drilling into the larvikite turns into the finest, stickiest mud imaginable when it gets wet, and it covers everything – car, boots, clothes. We are doing laundry right now in hopes that we have some clean clothes for tomorrow. As for the rental car, well, they are all all-terrain-vehicles aren’t they? The little Alfa Romeo has taken a beating on the quarry roads!

Working in quarries here in Norway is quite a bit easier than in Canada. Again for health and safety and legal reasons. In Canada, if the quarry is operating, you’re not allowed in. If it’s closed and defunct, chances are that you have to cross many barriers and blockades to access the workings. Here, unless they are blasting, you are free to wander in the quarry. Of course that does come with a certain responsibility – there are huge trucks moving throughout the quarry, drilling is taking place everywhere, and they are often pushing slabs off the walls. It can be dangerous. So the key is to be fully aware of your surroundings, know what a blasting cone looks like, and talk to the mine manager prior to going into the quarry. It’s pretty simple and everyone stays safe and happy.

Quarrying for larvikite here requires a few steps. First, connecting holes are drilled at vertically and horizontally into the rock face at each corner. When this is completed, a diamond wire (1.5 cm in diameter) is inserted into the top vertical hole and fed through the bottom horizontal hole until it emerges. The diamond wire, or diamond saw, is then connected to form a loop which is fed on a pulley on a mechanized platform at the base of the rock slab. This technology is actually from Italy where it is used in the marble quarries. When the saw is turned on, water is flushed down the drill holes and the diamond wire cuts slowly through the rock. As it moves down, the saw tension is kept by moving the entire machine backwards along the track. When the cut is finished, a similar cut is made on the opposite side and then the back. After all cuts are made with the diamond saw, a large splitter is used and the slab (~20 x 15 x 5 feet) is shoved downwards onto the lower bench. If the rock is homogeneous enough, it simply topples over. If it contains pegmatites or basalt dikes or is compromised by a fracture surface with slickenslides, then the slab will fracture on the way down. The mine managers don’t like pegmatites – they interfere with the quality of the quarried rock. Once down on the bench, the slab is drilled off into 10-15 ton blocks using an automated drill with 5 drill rods. These large blocks are then put onto container ships at the port in Larvik and sent out to be processed; very little processing is done here in Norway.