The Bay Area Pervious Concrete team went to visit Graniterock at their Aromas location. Lauren arranged for a tour with Graniterock with their testing group. We piled into a car wit Katha and Greg, both in the Graniterock materials testing group. First we went to visit Big Bill, the massive material spreader.
Big Bill (pictured above) was at the end of a 3mile conveyor belt bringing material from the waste end of the crushing processing to the spreader. The wheels were at least 10 feet in diameter! It was a massive machine! The material being spread looked like moon dust!
After leaving Big Bill we went into the quarry. You could see the step-like traces of material that had been removed. The terraces started at the top of the hill and went rather deep, below sea level! There was this massive truck (pictured above)that was moving the 'raw' rock and rubble close to the initial crushing machine (picture below). The crushing machine was in the quarry and it was even more massive then Big Bill the spreader! Here are a few photos of the team with the crusher. It was not running at the time, I would imagine it would be deafening! From the large initial crusher, another conveyor, shorter then the 3 miler, takes the material to the processing yard.
The material on the initial conveyor is then sorted into two sizes (big, for dry processing, and smaller, for wet processing) before being further sifted, crushed and rinsed to final product sizes and blends. The processing yard was a maize of conveyors, buildings on stilts (the crushing/processing/screening) and piles of material. Going into their control tower, we could see the levels of complexity and organization to keep all of that machinery moving that went unseen in the maize outside the windows. Even further beneath the surface of the processing yard was another conveyor in a tunnel beneath the main stockpiles, to allow for high control of the custom blends and product development.
Graniterock's newest addition to the quantitative analysis even had this fabulous quality assessment program that noted the size of final aggregate moment to moment to ensure consistency of the final product. They could, in real time, plumb their data and understand how consistent their product was, and make appropriate adjustments to bring it back into line. That type of feedback allows the quality team to be responsive to current inventory as well as give the operations team insights as to how well their processes are processing. It was a fantastic set-up, although I may be a data geek.
It was a fantastic tour of a great facility. We learned a lot about the aggregates that we use frequently in the Peninsula as well as how it gets to us. Really good quality rock makes even better pervious concrete! Please send us comments or questions! :)