Modern Mining June 2015

PRODUCT News

Hybrid roll crusher proves itself at SA colliery Onverdacht colliery indicated a hardness of 70 MPa, with the surrounding sand- stone at 150 MPa, we recommended this machine to management and began a test programme on the mine.”

Having delivered an impressive perfor- mance in several overseas applications, Sandvik CR810 hybrid roll crushers are now starting to prove themselves in the African mining environment. A recent two- year study conducted at Genet Mineral Processing’s Onverdacht colliery near Belfast in Mpumalanga has demonstrated that even extremely hard South African coal can be crushed in a primary or sec- ondary application at a cost as low as 55 cents per ton. Sandvik CR810 hybrid roll crushers store kinetic energy in the mounted fly- wheels (belt drive models) and the fast running fly wheels (direct drive models). A flywheel located on each roller delivers a crushing power up to four times that of a crusher without any flywheel, increasing the capacity and improving the maximum material hardness by nearly 65 %. This enables the machine to crush large lumps and maintain a stable crushing process even during peak conditions. “The Sandvik CR810 has proved ideal for primary and secondary crushing of materi- als that are soft to medium-hard, as well as wet and sticky,”says Sandvik Mining’s Colin Jones, Crushing and Screening Division, Region Africa. “Its compact design less- ens the required installation footprint and it utilises roller teeth with a large gap, allowing it to produce high quality output products with very low fines. “The teeth are installed in a line, instead of the conventional scroll pattern, at 120 degrees, which allows greater penetration into the crusher. The teeth are also inter- laced for bending and shearing, with a lower tooth that delivers compaction. The end result is a cubical product. Scrappers are fitted to keep the teeth clean and there is no other crusher in the world that has this feature.” Depending on the application and model, Sandvik crushers of this type can achieve capacities in a range of 100 up to 11 500 metric tons per hour (t/h) and can be used in primary, secondary and tertiary crushing applications. “Sandvik hybrid crushing technology was first tested on limestone and sand- stone in Europe and continues to deliver exceptional performance in these sectors today,” Jones says. “Two years ago, when sample analysis of the coal being mined at

The Onverdacht roll crushing plant has a capacity of 250 t/h with a static grizzly on the feed bin and the bars set 400 mm apart. Considering that the third dimen- sion was approximately 500 mm, the machine selected was the Hybrid CR810/ 08–10. This model incorporates rolls 800 mm in diameter and 1 000 mm long, and features rapid tramp metal release, self-cleaning of wet and sticky material and three dimensional crushing using a kinetic energy input. The machine was put into service in January 2013 with a gap setting of 100 mm where 90 % of the feed material passed. Shortly after the plant was commis- sioned, it was decided to reduce this gap to -75 mm to help the secondary crushers produce a final product of P100 < 40 mm. Roll speed is the same as material flow speed, so there is no retention time. In terms of maintenance and repair, in August 2013 it was noted that the fixed roll bearing was becoming hot. The bear- ing was repaired and the crusher was back in operation just four days later. Subsequently, in October 2013, a loose bolt was detected and the plant was shut down for 12 hours to tighten all the other bolts in the installation. Over the two-year trial period, plant availability was 98,6 %. “During the plant’s operation, power consumptionwas measured periodically for

both motors at 108 kW,” Jones says. “With a throughput of 250 t/h and using 60 cents per kWh, we determined that the consump- tion was 0,432 kWh, or 26 cents per ton. “By October 2014 the plant had produced about 1,5 Mt and the mine pur- chased a complete set of wear segments at a cost of R300 000. Based on the cost of the entire spare and wear parts and power consumption, it was possible to accurately calculate an operating expenditure (OPEX) figure of 55 cents per ton.” Rory Power, Group Maintenance Engineer at Genet Mineral Processing, says the Sandvik hybrid crusher has proved to generate fewer fines than previously expe- rienced with other crusher configurations. A second Sandvik CR810 hybrid roll crusher is in operation in South Africa in a chrome application and three are at work in the DRC crushing copper ores and gold oxides. Sandvik Mining, tel (+27 11) 929-5400, website: www.mc.sandvik.com/za The Sandvik CR810/ 08–10 hybrid roll crusher installed at Onverdacht colliery near Belfast in Mpumalanga.

Flowmeter is a ‘plug and play’ solution With no cables or other parts protruding past the flanges, compact dimensions and a low weight, the UFM 3030 flowmeter from KROHNE is very easy to handle.

The outer casing of the UFM 3030 is an all metal con- struction and there is therefore little risk of damage to the flowmeter during the installation process. The flowmeter is delivered ready to measure. Once mechanically and electrically connected, the unit does not require any specific handling such as fitting sensitive transducer parts or making specific cable connections. In case of a remote installation, a cable with pre-fitted connectors is provided. In this way the signal connections are easily made without the need for special handling. The cable length can be selected from 5 up to 100 m. KROHNE, tel (+27 11) 314-1391

June 2015  MODERN MINING  55