Institute of Coal, Federal Research Center of Coal and Coal Chemistry, Siberian Branch, Russian Academy of Sciences, Kemerovo, Russia:

V. I. Klishin, Director, Corresponding Member of the Russian Academy of Sciences
B. A. Anferov, Leading Researcher, Candidate of Engineering Sciences
L. V. Kuznetsova, Leading Researcher, Candidate of Engineering Sciences, lvk@icc.kemsc.ru

In the Kuznetsk coal basin, about 9 billion tons of balance coal reserves of categories A + B + C1 are concentrated in thick (more than 5 m) seams down to a depth of 600 m, of which 70% have a dip angle of up to 20 degrees. The most effective technology for mining such seams is their excavation at full capacity—Longwall Top Coal Caving method (LTCC). In this technology, destruction of top coal is carried out by underground pressure, and powered roof supports have outlet windows connected with chute and feeder. Caved top coal is discharged to the face conveyor. The technology can: reduce operational losses and ash content of coal due to the controlled discharge; provide the face output up to 15.0 kt/day (4.5 Mt/yr); reduce the cost of installation and dismantling of LTCC systems (powered roof support, haulage machines, pipelines, preventive measures, etc.); lower the production energy input by 25–30%; cut down the cost of expensive and metal-intensive longwalling and haulage equipment. The effectiveness of the technology depends on the quality of the top coal preparation to be discharged onto the face conveyor. The methods for preparing top coal for the discharge alongside with the face advance are proposed. In mining seams 5–6 m thick, top coal is split into portions by means of cutting longitudinal channels by a shearer. When developing layers with a thickness of 6–12 m, the top coal is split into portions by drilling wells and filling them with hydraulic stemming containing aqueous solutions of non-explosive expanding mixture.

1. Shaklein S. V., Pissarenko M. V. Alternative coal mining technologies as a basis for intensive development of mineral reserves and resources in the Kuznetsk basin. Gornaya promyshlennost. 2010. No. 4(92). pp. 22–25.
2. Klishin V. I., Shundulidi I. A., Ermakov A. Yu., Solovev A. S. Technology for thick coal seam cutting with coal discharging. Novosibirsk : Nauka, 2013. 247 p.
3. Ermakov A. Yu., Kachurin N. M. Justification of aerologically safe single-stage mining technology for thick gently dipping coal seams with controlled caving from interlayers and roof. Kemerovo : Kuzbassvuzizdat, 2018. 290 p.
4. Kalinin S. I., Novoseltsev S. A., Galimardanov R. Kh. et al. Longwall top coal caving in thick seams. Kemerovo, 2011. 223 p.
5. Ning Shi, Zhizeng Huang. Application of Longwall Top Coal Caving in Challenging Geological Conditions. Proceedings of the World Congress on Mechanical, Chemical, and Material Engineering. Barcelona, 2015. Paper No. 354.
6. Nadia Sultana Tarakki, Chowdhury Quamruzzaman, Mohammad Tofayal Ahmed, Md. Mizanur Rahman, Md. Badrul Alam, Chowdhury Rayhan. Longwall Top Coal Caving Method for Barapukuria Coal Field, Dinajpur, Bangladesh. International Journal of Scientific & Engineering Research. 2016. Vol. 7, Iss. 4. pp. 285–293.
7. Le T. D., Mitra R., Oh J., Hebblewhite B., Zhang C. A Review of Roof Instabilities Associated With Longwall Top Coal Caving. Proceedings of the 52^nd U.S. Rock Mechanics/Geomechanics Symposium. Seattle, 2018.
8. Moodie A., Anderson J. Geotechnical Considerations for Longwall Top Coal Caving at Austar Coal Mine. Proceedings of the 11^th Underground Coal Operators’ Conference. Wollongong, 2011. pp. 29–39.
9. Tien Dung Le, Rudrajit Mitra, Joung Oh, Bruce Hebblewhite. A review of cavability evaluation in longwall top coal caving. International Journal of Mining Science and Technology. 2017. Vol. 27, Iss. 6. pp. 907–915.
10. Medhurst T., Rankine R., Kelly M. Development of a method for a longwall top coal caveability assessment. Proceedings of the 14^th Coal Operators’ Conference. Wollongong, 2014. pp. 42–50.
11. Caterpillar to supply two complete longwall top coal caving systems to mine in Turkey. 2014. Available at: https://www.mining.com/web/caterpillar-to-supply-two-complete-longwall-topcoal-caving-systems-to-mine-in-turkey/ (accessed: 14.06.2019).
12. Klishin V. I., Fokin Yu. S., Kokoulin D. I., Kubanychbek uulu B. Mining of thick seams with powered roof supports and controlled coal discharge. Novosibirsk : Nauka, 2007. 135 p.
13. Klishin V. I., Anferov B. A., Kuznetsova L. V. Improvement of technology with top coal caving in thick seams. Innovations in fuel and energy complex and mechanical engineering : Proceedings of the International scientific–practical technology. Kemerovo : KuzGTU, 2017. pp. 57–63.
14. Senkus V. V., Ermakov A. Yu. Development of process flow diagrams for top coal caving in thick gently-sloping seams. GIAB. 2016. No. 5. pp. 319–327.
15. Pavlenko M. V. Wave excitation and generation of oscillations in holes for making gas drain cracks in coal. GIAB. 2015. No. 1. pp. 129–136.
16. Tatsienko A. L., Plaksin M. S., Ponizov A. V. The main technical aspects of coal seam fracking technology implementation. Vestnik Kuzbasskogo gosudarstvennogo tekhnicheskogo universiteta. 2017. No. 3. pp. 30–37.
17. Sorin Mihai Radu, Andras I. Improved Mechanised Extraction Technologies in Underground Hardcoal Mines from Jiul Valley-Romania. MultiScience – XXIX : microCAD International Multidisciplinary Scientific Conference. Miskolc, 2015. DOI: 10.26649/musci.2015.011