The 2200 SM 3.8 surface miner operates according to the windrowing method: after cutting the material, it deposits it in three windrows behind it.

THE first Wirtgen 2200 SM 3.8 surface miner is being used at a coal mine in northwest China’s Xinjiang province. This new surface miner is replacing conventional mining equipment used locally and Wirtgen experts are providing support.

Contractor Xinjiang Jianyun Engineering Co Ltd has been mining at Yihua Xinjiang Wucaiwan mine for about 18 months, making use of the eco-friendly surface mining technology. Previously, the coal was mined using conventional methods which often resulted in fires in the mine, as the coal was highly flammable at the open faces damaged by blasting. To increase safety, the mine operator decided to introduce surface mining, simultaneously boosting cost effectiveness and quality of mining.

Simply choosing the right machines for the specified mining output is not the sole criteria when planning projects. Factors such as geological properties of the area, sedimentation and on-site logistical conditions are also key. This is where expertise and best-practice experience are called for and with more than 30 years of experience in surface mining, these are qualities that Wirtgen can contribute. “The Wirtgen specialists provided us with in-depth advice right from the start and assisted us in developing the ideal solution,” said Xinjiang Jianyun owner Chen Jianyun, who values the partnership-based cooperation and reliability of the surface miner.

The mining area is 2 x 300 x 35 metres so manoeuvrability was a key factor. Also, the operator wanted to increase daily production from 3000 to 7000 tonnes in order to meet the demand from the main customers, who operate a cogeneration plant and a fertilizer plant.

The coal is also extremely fragile and fine-grained, producing a great deal of dust. Various requirements on gradation of the cut material and the coal seam (with thickness ranging from 1.3 to 10.63 metres) had to be taken into consideration.

“Once we’d been apprised of the conditions, we advised our customer to use the 2200 SM 3.8 surface miner. Though based on the same machine concept as the 2200 SM/3800, its production capacity is about 25% higher and specific fuel consumption about 15% lower,” explained Wirtgen’s Mining Division manager Bernhard Schimm.

The machine selectively mines soft rock, achieving a maximum in performance and cost efficiency. “We scrutinized the results of tests with the prototype of the new 3.8 in an Indian mine and concluded that the 2200 SM 3.8 fulfils our requirements,” said Chen Jianyun.

The centrepiece is the 3.8 metre-wide cutting drum which offers numerous features. It cuts coal or salt with unconfined compressive strengths of up to 35 MPa and deposits material in three windrows, resulting in maximum cutting performance with optimum utilization of engine capacity.

Other benefits are low fuel consumption, optimized use of cutting tools and minimized content of fines due to the gentle material transport system. The modified drum speed combined with reduced cutting depth and travel speed enabled grain size distribution to be additionally optimized on site and the fines content to be reduced by a further 10%.

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