IM 2017 September 17 | Page 46

MECHANISED COAL n Increase of safety level of mining works n Consistency of underground development n Increase of efficiency and cost effectiveness of production n Fulfilment of planned production in order to satisfy demands of the region’s power stations. Throughout 2017, Becker-Warkop is delivering another mechanised complex to Zenica mine. Roadheaders/CMs Steady-state production from the Kakanj longwall is 2,000 t/d. The mineable seam thickness is 3.2 m, face length 120 m, panel length 500 m and seam inclination up to 8°. It’s an Eickhoff SL-300 shearer with Becker-Warkop supports, face conveyor, reloader and crusher On July 19, 2016 acceptance and testing of the purchased equipment took place at Becker- Warkop's production plant in Świerklany (Poland). As a result of the tests, all required specifications were confirmed. The hydraulic support system delivered to Kakanj mine was tested for 60,000 working cycles and consists of the following Becker-Warkop equipment: n Hydraulic supports BW 15/36 POz (80 in total) n Face conveyor PZS BW 230/750 n Reloader PZP BW 230/750 n Crusher KDBW 800-1200 produced by Becker- Warkop. The shearer is an Eickhoff SL-300. Becker-Warkop says this new mechanised complex provides: The largest Russian coal producer, Siberian Coal Energy Co (SUEK), recently placed an order with the regional Cat ® dealer, Vostochnaya Technica (VT), for a complete AFC system to equip the company’s second 400 m longwall face. The longwall will operate in the mine in Kemerovo District named after V.D. Yalevskyi, Yalevskogo Seam #52 (formerly Mine #7), with commissioning planned for early next year. In April, SUEK commissioned the first 400 m (1,300 ft) longwall face in Russia in the same mine, but in Seam #50, formerly called Kotinskaya. Previously, the widest longwall face in Russia was 300 m. The equipment for the face extension and the upgrade of the AFC system was manufactured by Caterpillar and assembled and commissioned by VT. The longwall systems at the two faces average cutting heights of approximately 4 m. The new system for Yalevskogo consists of a Cat AFC PF6/1142 with three drives of 1,000 kW each and Cat CST65 gear boxes, a Cat PF6/1342 beam stage loader with a Cat SK11/14 crusher and a belt return unit. The AFC system will go into operation with Cat roof supports. With its patented trough concept and durable pan design, the Cat AFCPF6 face conveyor is particularly suited for applications in longwalls with extended face length and for panels with coal reserves of 10 Mt and more. The innovative design of the PF6 line pan allows the separation of wear parts and structural parts. Very hard, wear-resistant materials are used for wear parts, while the structural parts are made of high- strength steel 44 International Mining | SEPTEMBER 2017 Roadheaders and continuous miners (CMs) are generally the machines of choice to develop longwalls, and CMs are of course the preferred primary mining machine for room and pillar mines. However, roadheaders are getting much better at cutting tough rock. At Barrick Gold’s Cortez mine, a Sandvik MH620, one of the world’s largest roadheaders is steadily cutting two new declines to the lower section of the operation’s underground deposit. Barrick chose mechanical cutting instead of traditional drill-and-blast to develop the new portals, the first time a roadheader has ever been used at the mine. The company is also set to introduce a roadheader for ore production at its nearby Turquoise Ridge gold mine in 2017. It’s a paradigm shift towards continuous mining that Barrick expects will bring significant economic and safety benefits to its Nevada operations. Jim Wieser is the safety manager for Drill Tech on the Cortez contract. He says “roadheaders are definitely better for long-term development.” Roadheaders are often a more cost-efficient alternative, eliminating the need for drilling, blasting and mucking and reducing ground support costs. Rock is conveyed directly onto haul trucks as the roadheader continuously carves out an extremely accurate tunnel, minimising overbreak. Weighing 125 t, the Sandvik MH620 cutting the declines at Cortez is one of the world’s largest roadheaders. A 300 kW cutting motor drives twin rotating cutter heads that are manoeuvred by a large hydraulically-operated boom. It is engineered for economical excavation of hard, abrasive rock with compressive strengths exceeding 120 MPa. A robust, hydraulically stabilised telescopic cutter boom optimises cutting power, ensuring rapid roadway development. Wieser, who’s operated smaller roadheaders from Sandvik predecessors Voest-Alpine and Dosco in previous projects, estimates some of the hardest black limestone Drill Tech has encountered at Cortez to be in the 12,000-15,000 PSI range. “The MH620 has no trouble cutting it,” Wieser says. “The roadheader itself stays stable and doesn’t move around and jump around and beat itself to death. It’s a great machine for the harder- type material.”