Swann Blaise presents a case study on a mining excavator in operation in South Africa
The Beeshoek Iron Ore mine, is situated approximately 65km south of Assmang’s flagship Khumani Iron Ore mine, near the town of Postmasburg in the Northern Cape province of South Africa. Composed of five open-cast pits, Beeshoek’s production output is around 3.4 million tonnes a year. The mine is jointly managed by ARM Ferrous (a subsidiary of African Rainbow Minerals) and Assore, through Assmang.
Beeshoek undertakes its own mining but also contracts out a smaller proportion of its mining requirement through a Plant & Hire contract, attributed to South-Africa based company, Basil Read. This company is active in opencast mining, civil engineering projects, road construction, building, mixed integrated housing developments, property development and related services, and is among Liebherr’s major customers. As of 2015, Basil Read holds a fleet of 20 Liebherr mining excavators, including five units operated at Beeshoek mine. To sustain Assmang’s ambitious stripping target and initially as part of a prototype agreement with Liebherr, Basil Read was the very first operator of the new R 9200, since February 2015. As the machine demonstrated high performances and has successfully passed the field test period, Beeshoek decided to purchase it.
The R 9200 working at Beeshoek offers availability exceeding 90%. The machine has been developed to promote easy and fast maintenance: its manually actuated service flap is accessible from the ground level and offers direct access to fuel, engine oil, grease, hydraulic oil refilling points. Fitted with quick couplings Wiggins for all fluids as a standard feature, the required time to refill each fluid is consistently reduced to minimise machine downtime. In addition, all major service points are centralised for easy access from the central service platform, with all systems and design solutions simplified to facilitate maintenance. All of these arrangements promote fast service enabling users to increase machine uptime. R 9200 uptime performance is also supported by its impressive fuel burn efficiency as reaching up to 30 hours of fuel autonomy in standard configuration.
Reliability in extreme conditions
The R 9200 has been designed to fully answer requirements of the mining industry. As a result, the machine working at Beeshoek high reliability, which widely contributes to reducing the maintenance costs. In addition to the large integration of components designed in-house by Liebherr specially for mining, the R 9200 design is inspired from larger, proven Liebherr mining shovels, combining the R 994 undercarriage and new technologies of the new excavator generation. The undercarriage employs the 'Hook & Key' system with horizontal bolting as link between its side frame and central piece for highest torsion resistance and is equipped with heavy duty rock protections preventing accidental component damage. To promote hydraulic components and diesel engine continuous efficiency, the R 9200 includes various advanced features to support cooling efficiency of sub-systems, avoiding overheating. This is particularly appreciated in such conditions as Beeshoek, where temperatures frequently reach up to 50°C (122 °F).
The R 9200 is powered by a single Cummins QSK38 diesel engine, delivering a gross power output of 810kW (1,086hp). Promoting well-balanced energy consumption and employing low energy consumption auxiliaries, the R 9200 maximises net power available for the working process. Fitted with the Litronic Plus system for intelligent power management and using a closed-loop swing circuit, the R 9200 achieves super-fast cycle times as measured at 23 seconds at Beeshoek. Fitted with a 10.0 m3 (13.08 yd3) XHD bucket to load material with a loose density of 2.3 t/m³ (3,878 lb/yd³), Basil Read’s R 9200 efficiently loads 100t dump trucks in five passes. A performance study conducted at Beeshoek demonstrated the R 9200 was able to achieve an average production of 1,850 tonnes per hour.
Swann Blaise is with Liebherr.