Modern Quarrying Q3 2019

The Sandvik CS430 cone crusher was purchased to create operational flexibility.

Adam Taylor of Sandvik (left) with Jeremy Hunter- Smith, CEO of Blurock Quarries.

The reason we selected this particular scalping screen was because of its compact build and high throughput, which allowed us to sidestep the space constraints we had onsite,” says Hunter-Smith. The Sandvik CS430 cone crusher was purchased because Blurock wanted to create flexibility by being able to take out some of the products at the scalping screen before and after the secondary crushing stage before the product reported to the maintenance stockpile. This has been made possible by the CS430’s ability to produce a better aggregate shape earlier in the crushing process. In terms of plant design, the Sandvik CS430 cone crusher has been designed to allow the crusher to run either full or empty, with a dedicated feed bin feeding into it. “We built a big feed bin before the cone crusher, which is good crushing practice because you have the necessary continuous feed into the crusher,” says Hunter- Smith. “Once everything has been set up, we will install an automated door on the feed bin – if the crusher is full, it will stay open, but if there isn’t enough material in the bin, it will close the door and wait for the bin to fill so that the crusher will never run three-quarters or half full. It will either be full or empty – that’s the best way to run a cone crusher.” The scalping screen allowed Blurock to take out some of the product at the secondary stage. From the new Sandvik SS1633H scalping screen, they are now able to take out a handstone, G5, general concrete stone and dump rock material. “The investment into a scalping screen and the whole secondary setup was to facilitate the manufacture of all products that we want using our main plant, instead of having to rely on our mobile crushing and screening train for some of the products. The second- ary stage upgrade is definitely money well spent,” says Hunter-Smith. The results of the plant upgrade are apparent – with the old plant system, Blurock had the capacity to produce about 100 t per hour. “We were very limited because of the old equipment we had. Following the upgrade – through Sandvik product and other efficiency improvement mea- sures – we are now able to produce between 170 and 180 t per hour,” concludes Hunter-Smith. l

in feed conditions. By continuously measuring and com- pensating for crusher liner wear, the automation system allows for full utilisation of crusher liners and schedules liner replacements to coincide with planned maintenance stops. It also assists in keeping the crusher choke fed. This maximises rock-on-rock crushing, which helps to optimise the quality of the final product,” explains Taylor. Installing the Sandvik CH440 has altered the whole tertiary section setup while producing the exact quality that was achieved by having a fine cone crusher in the mix, says Hunter-Smith. “Another major benefit is that we have managed to relieve the pressure on our VSI. We are able to reduce the speed of the VSI due to the CH440’s attrition crushing. Reducing speed on the VSI also lowers the amount of 0,075 mm material in our crusher dust. Our concrete and asphalt manufacturing customers want as little 0,075 mm as possible in their crusher dust,” explains Hunter-Smith. Along with the Sandvik CH440, Blurock purchased the SV1252 vibrating grizzly feeder (VGF). This feeds the Nordberg 1109 primary crusher and was bought to improve feeding capacity at the primary crusher. “In terms of selec- tion, we looked at other manufacturers, but the Sandvik VGF fitted perfectly into our existing structure. Our previ- ous VGF created a bottleneck as we could not get enough feed into the jaw, so we were not running the jaw full. That resulted in poor liner wear and poor attrition crushing,” adds Hunter-Smith. Secondary stage upgrade In early 2017, Blurock started looking at its whole secondary crushing application. It engaged the services of Imilingo Mineral Processing, which designed the new secondary crushing layout. The quest to improve efficiencies at the secondary crushing stage started with the purchase of a Sandvik CS430 cone crusher. This was purchased in 2016, but was only installed in 2018. “It was the exact crusher we needed to upgrade our whole secondary crushing application,” says Hunter-Smith. As part of the new layout, a Sandvik SS1633H scalping screen was bought in November 2017. “We started instal- lation in December 2017 and commissioned in June 2018.

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QUARTER 3 - 2019 MODERN QUARRYING