Acceptance of surface miners in quarrying applications is growing in some parts of the world. Colin Ford explains how, with the right geological deposits, many quarries could benefit from the productivity and cost benefits of surface mining.
Wirtgen developed its surface miner range in the 1980s as a spin-off of its road milling technology and uses the same ?drum-mounted milling tool concept. The machines were aimed at large open-cut mines and are larger than their road building counterparts. The surface miner range consists of the 50 tonne 2200 SM, 110 tonne 2500 SM and 200+ tonne 4200 SM.
COST EFFECTIVE ALTERNATIVE
Around half of Wirtgen?s surface miners operate in limestone quarrying applications and are suited to residential areas where blasting noise and vibration can be an issue. Surface miners can provide a solution for quarry operators with environmental restrictions that limit drilling and blasting. They can also lead to the elimination of primary crushing and save double handling by direct loading of cut and crushed material into trucks for transport from site.
Trials in limestone and sandstone quarries in New South Wales and Queensland will be conducted in 2010.
The 4200 SM is the largest in the range and completes the generation Wirtgen began in 2000. The 211 tonne 4200 SM has a 4200 mm cutting width and can mine a depth of up to650 mm in hard rock and 830 mm in softerrock in one pass, at speeds up to 20 m per minute. The drum and picks can be matched to meet a customer?s requirements for material gradation. The machine has a 180 degree slew-able height adjustable conveyor and can load 240 tonne capacity dump trucks at 3000 tph.
The machine is mounted on four crawlers with three different steering options that can deliver a turning circle of 12.5 m. Safety has been a high priority with the design which meets all necessary statutory regulations. It is surrounded by walkways and stairs with handrails. Access to the cab is by hydraulic fold-down steps and all daily maintenance points have ground level access. Fortescue Metals Group is currently using a 4200 SM at its Cloudbreak site to mine iron ore and has ordered five more for delivery in 2010.
SUCCESSFUL OPERATION IN LIMESTONE
While the 4200 SM may be too large for quarry applications, the 2200 SM and 2500 SM are used in numerous quarries worldwide. The Euro Cement Group Holding, based in Russia, is operating two 2500 SMs in the expansion area of the Dzhegutinsk limestone quarry of ZAO Kavkaz cement. These machines each produce 5000 tonnes of limestone per operating shift – equal to a monthly production of 200,000 tonnes.
Colin Ford is the mining manager of Wirtgen Australia Pty Ltd.