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The company added that when the "Auto-CSS" regulation mode is selected, the ASRi aims to maintain the stipulated CSS. Alternatively, in "Auto-load" mode, the system focuses on keeping the selected set-points for the main motor power con- sumption and main shaft hydroset pressure, such that the crusher operates at the required load level. If the highest per- mitted load level is selected, maximum reduction will occur as the CSS will always be the smallest possible. According to Sandvik, the software package supplied with the ASRi includes an OPC-server that allows seamless integra- tion with superior control systems such as SCADA and DCS sys- tems. This communication provides complete access to all the parameters in the ASRi as well as allowing adjustments to be made remotely during operation. For customers who do not wish to build their own pictures in SCADA, Sandvik supplies its WINi graphics software option. This can allow a customer to control their ASRi remotely using the same graphical user interface as on the ASRi. Sandvik makes the analogy that it is like installing an extension of ASRi on a PC, so that a control-room operator can independently select pages on WINi without interfering with the operator in the field. It is also possible to have different settings on WINi than on ASRi—such as language and units. Where an operation has more than one ASRi, the WINi software can be used with up to nine different ASRis, displaying them on an overview picture, so that the user can easily monitor and compare several machines at once. Sandvik pointed out that automated systems are not just limited to overall crusher control. Proper lubrication will maxi- mize the lifetime of vital crusher components, for instance. All of its CH800 series and CG series crushers are equipped with a Tank Instrumentation Monitoring System (TIMS), which mon- itors all auxiliaries in the crusher to ensure optimized lubrica- tion. Meanwhile, the lubrication system for its gyratory crush- ers is designed to be controlled by variable-frequency drives (VFDs), using flow meters to deliver exactly the right flow into the crusher. Field Experience Sandvik gave some examples of the benefits that can be gained from using its ASRi control system. In a CG-type primary gyra- tory, if a big rock becomes jammed in the crusher intake, the ASRi system allows the operator to switch from "automatic" to "manual" mode so that the crusher can be opened. This might help to re-orientate the rock sufficiently to enable it to be crushed. The ASRi is then switched back to "automatic" and the crusher returns to normal operating conditions, with mini- mal disruption to production. The company cites an installation at the Teberebie gold mine in Ghana, which used a size 54-74 primary gyratory crusher equipped with ASR+ (an older version of ASRi). Flexible crusher operation was essential as the mine produced three different types of ore—hard, soft and sandy—each with different crushing characteristics. Each ore type had its own individual operating programs with preset parameters in the ASR+, allowing the operator to select the correct program depending on the ore type. The crusher could then work at the optimal settings so as to best utilize its capabilities, without any risk of overloading. In a second example, Sandvik describes a case where an oper- ator has several CH870 crushers with ASRi and WINi installed, allowing crushing to be operated from a control room. The same operator also has some bowl-type crushers on site and, the com- pany said, has commented on the difference when calibrating. As this particular customer is dependent on a certain prod- uct size, they run their CH870s on Auto CSS, which automati- cally learns and compensates for wear. However, Sandvik said, they wanted to be completely sure about the setting. Taking just 30 seconds to complete, the ASRi allows them to calibrate the crusher several times a day to ensure that the product size is indeed correct. With the bowl-type crushers, the situation is completely dif- ferent, Sandvik pointed out. The customer needs to go out to the crusher, stop the feed, unclamp the bowl, manually meas- ure the setting and reclamp the bowl, before restarting the feed. As this takes more than 30 minutes, it is only done once a day because of the crusher downtime involved, so the prod- uct size is not as consistent. HPGR Presents Other Challenges With high-pressure grinding rolls (HPGR) offering a viable alter- native to conventional crushing in appropriate situations, acceptance of this technology is becoming increasingly wide- spread within mineral production. Yet, as Siemens pointed out, controlling an HPGR installation presents a different set of challenges, particularly in relation to keeping wear at an accept- able level. The company noted that since HPGR operations have to be designed to perform at optimum efficiency to minimize exces- sive energy and maintenance costs, its optimized drive systems can help by providing accurate speed and operating torque con- trol. Siemens claimed that by matching the best-suited compo- nents at each step from its extensive drive system, motor, gear- box and load-distribution control product portfolios into a com- pletely integrated system, it can ensure that HPGR installations can handle large overloads for long periods. JUNE 2014 • E&MJ; 59 www.e-mj.com C R U S H E R S An ASRi is being used to control a Sandvik CH800 series crusher. EMJ_pg58-63_EMJ_pg58-63 6/3/14 3:06 PM Page 59