MECHANISED COAL AND SOFT ROCK
longwall mining was the Wachangping mine in Wuchuan Country , Guizhou Province , beginning with the 1102 panel in 2018 . The mine is owned by the State Power Investment Corporation and operated by its subsidiary Wuchuan Alumina , which went on to also apply what it calls “ Technology of Comprehensive Mechanized Excavation ( TCME )” at Dazhuyuan , one of its other major bauxite mines in Guizhou , in 2019 .
The traditional method of underground bauxite mining mainly involves blasting , which has low mineral recovery rates , high depletion rates , low mining efficiency and high production costs , CCTEG says . After eight years of exploration , CCTEG ’ s team proposed a layered section mining method and a small drum incline cutting process , which were all first-of-their-kind .
The bauxite mining field has the characteristics of multiple dissolution cavities , faults and thin and discontinuous ore veins . It also has high hardness and strong erosion characteristics of alumina-rich bauxite ores and cemented soil materials . CCTEG developed a large cutting force , low-speed mining system along with a long-life walking system . The application of these original technologies has significantly improved mining efficiency and grade while reducing production risks , according to the company .
The new technology and equipment for mining medium-to-high hardness minerals has broad application prospects not only in bauxite , but also in the phosphate and potash mining industries , CCTEG concludes .
JSW ramp up continues
Four longwalls have recently been put into production at Jastrzębska Spółka Węglowa ( JSW )’ s operations in Poland , with resources of nearly 1.9 Mt of coking coal set to be extracted . Currently , Poland-based JSW operates 23 longwalls , with the company on the road to recover from events that occurred in 2022 at the Zofiówka Section and KWK Pniówek , plus longwall fires at the Budryk and Pniówek mines in 2023 .
Due to these events , JSW ’ s Management Board decided to remodel some work fronts .
In June , two longwalls were put into operation at the Pniówek mine , with the first – the B-3 longwall – being 218-m long with a strike of 790 m . It will be mined until February 2025 and its resources amount to 340,000 t . The second longwall in Pniówek , C-5 , is slightly shorter , coming in at less than 100-m-long , with a strike of 375 m . The C-5 longwall ’ s resources are 140,000 t and will be mined until September .
At the Zofiówka Section , the C-10 longwall that has just been put into operation has resources estimated at some 400,000 t from a longwall that is 230-m long , has a strike of 550 m and is expected to be mined until February 2025 .
The Knurów Section has also put into operation its largest ( 14th ) longwall , with estimated coal resources of 1 Mt . The 245-m-long longwall has a strike of nearly 1.5 km and will be in operation until January 2026 .
Adam Rozmus , Vice-President of the JSW Management Board for Technical and Operational Matters , said : “ We are all working hard to return to pre-2022 production levels . We hope to operate 26 longwalls in Q4 ( December quarter ).”
A lease of life
Still in Poland , FAMUR reported in its March quarter results that it had witnessed demand for its aftermarket solutions – from both foreign and domestic markets – involving machinery and equipment maintenance , repairs and supply of spare parts , as well as shearer loader and roadheader leases .
JSW plans to have 26 longwalls operational across its Polish mines by the end of the year
Pillar extraction is back on the agenda again and NEPEAN Longwall is proving the coal mining doubters wrong with an ambitious and innovative project that , it says , may lead to an industry step-change , prolonging the life of underground operations by supplying a system that combines elements of both longwall and room & pillar mining methods .
Australia-based NEPEAN Longwall has a value proposition that spans all aspects of longwall mining equipment , including armoured face conveyors , beam stage loaders , shearers , drive units , electrohydraulics , chain and flights , hoses , cables and other specific componentry .
It is known for its tailored engineering capability , and its latest project – a world first – will do that reputation no harm .
“ We are different to other major players in this sector as we embrace customised solutions for our customers to a greater extent ,” Mark O ’ Toole , Business Development Manager of NEPEAN Longwall , told IM . “ We are not trying to protect an inflexible supply chain , and that allows us to design the best solution for each customer .”
NEPEAN Longwall has recognised the changing market in Australia where new mine approvals are more difficult than ever , access to capital is constrained and customers are looking for cost-effective solutions to make the most of their underground reserves .
It was Centennial Coal ’ s Clarence mine in New South Wales and its Panel & Pillar Partial Extraction Project that gave NEPEAN Longwall the opportunity to focus on innovative mining methods using existing technologies . Centennial ’ s project started with concepts generated by Robert Langford ( Engineering Manager , Clarence Mine ), which NEPEAN Longwall turned into reality with the new system .
“ There are now a number of new bord and pillar coal mining projects emerging in Australia as open-cut operations seek to access deeper reserves and head underground ,” O ’ Toole said . “ Bord and pillar operations can extract the resource quite efficiently , but this can drop off in some conditions such as lower seams .”
Longwall mines , on the other hand , rely on the complete extraction of the coal in a panel arrangement . As the panel is mined , complete subsidence or caving of the overlying rock strata occurs into the mined-out area behind the working mine face .
Pillar extraction disappeared to a large extent from Australian mines in the late 1990s due to safety concerns about the s
64 International Mining | SEPTEMBER 2024