A Great Challenge: Assembling Inclined Longwalls
Seen here on the shop floor, Famur designed and manufactured the Roof Support Transportation System (FRTS-900) to move heavy longwall mining equipment such as shields, shearer components, etc., in undulating or dipping seam conditions. A set of revolving platforms (or turntables) are visible on each side of the flatcar’s hydraulic power unit.
Inclined seam longwall extraction is a great challenge for miners. Longwall operations in dipping seams can be found in Poland, Russia, China and Kazakhstan. Face operations with inclined longwall faces are much more difficult compared to horizontal longwall faces. Inclined longwall faces require close attention and good, experienced miners as well as a few additional options for operations. For roof supports and armored face conveyors (AFCs), additional equipment is needed for stabilization and positioning.
One of the greater challenges initially is assembling longwall face equipment on an inclined face. In addition to the problems associated with transporting on an inclined face, roof supports are typically stable to an inclination of 15°. In many fully mechanized longwall faces in Russia, Kazakhstan and also Poland, the longitudinal inclination can be as high as 35°.
For a long time, large rope hoists and winches were typically the best approach for the heaviest equipment, especially transporting and positioning the roof supports along the start line. The operation, however, was very dangerous and laborious. Positioning the roof support was especially difficult and dangerous because of the importance of aligning the roof support exactly as required (and exactly opposite to the AFC panline). In some Polish coal mines they used remotely controlled winches, ropes and hydraulic cylinders. The operators were able to watch using video cameras, which was a much safer situation, but still labor intensive.
For ArcelorMittal’s coal mines in Kazakhstan, where Famur equipment is being used, this problem was particularly important.
A Challenging Objective
In underground coal mines in Kazakhstan, where seams are inclined, the most popular transport equipment are monorails. The small tunnel and entry dimensions, however, require roof supports to be transported from face to face in pieces, disassembling the units at the stop line and re-assembling them at the new start line. The mine asked Famur’s engineers several questions in effort to improve safety and efficiency, including:
- How could we improve safety during the face assembly process?
- How could we make face assembly more effective?
- What could we do to reduce the costs associated with the assembly process?
Famur’s engineers and designers performed an extensive review of existing solutions and equipment; they proceeded to design a new solution.
The solution was the FRTS-900 Roof (Support) Transportation System, which is intended to transport heavy equipment, such as roof supports, as well as other materials needed for longwall mining, including shearer components, AFC panline, etc. The system can be used during start line development and face installation as well as recovery fully retreated longwall panels and any other purposes. Moreover, through the integration with the powered roof support turntable (a revolving platform), the FRTS-900 system better enables the loading and unloading of roof supports (shields) onto and off of the transport platform, turning/rotating and installing the shields along the longwall face.
Developed to the customer’s expectations, the FRTS-900 system has been designed to transport large components (hydraulically powered shields) weighing as much as 29.5 metric tons (mt) on longitudinal inclinations of up to 35°; obviously with smaller longitudinal inclinations, the weight of material to be transported could be greater. Its modular design enables easy adaptation to various transport route profiles (differing longitudinal inclinations, turns and undulations).
The main FRTS-900 components include:
- Maneuverable tractor;
- Trailer (platform);
- Rails as complete pans; and
- Revolving platform.
Mobility & Maneuverability
The maneuverable tractor FFST-90 is intended to move the transport set on the track. The tractor is assembled as a truck with electric propulsion, with high-pressure hydraulic pump and two kinds of hydraulic haulers. Haulers are moving the entire train (tractor, trailer/platform) on the railroad. The Basic Hauler No. 1 (with four hydraulic engines) is the main drive unit for the FFST-900 maneuverable tractor. Hauler No. 2 is an auxiliary hauler that may be additionally connected to the maneuvering tractor to increase the pulling force when more demanding mining conditions and transport requirements occur.
Typical electric cable length is 320 m, but it can be customized upon request.
The trailer (flatcar) is intended to transport equipment and materials on floor-mounted systems. The maximum payload (utility weight) is 320 kN (it is possible to apply a smaller trailer of 60, 120 or 220 kN). The FPR-900 railroad is composed of repetitive sections of straight and curved rails 900 mm wide, adapted to the route. The radius of curvature is 4,500 mm on a horizontal plane and 10,200 mm on a vertical plane. The revolving platform (turntable, rotary unit) is integrated with other system components; it is installed at the route end of the longwall face and is intended for unloading the powered roof support shields of the transport platform (trailer), turning and installing/positioning precisely in the face. After each installation of successive roof supports, the route is shortened by one or two sections (segments), and the revolving platform is placed into a new position. Similarly, when roof supports are being disassembled/removed from the face, the revolving platform enables turning and loading of the shields to the FRTS-900 system transport platform (flatcar).
A completely assembled system was tested at the Famur plant in Katowice, Poland, and successfully certified. The FRTS-900 is certified for all coal mines (including high-methane and high-dust mines). It can work in temperatures of 5°-35° C (41°-95° F) and air humidity of up to 95%.
In November 2015, Famur delivered the system to ArcelorMittal in Kazakhstan. This January, the entire system was assembled in one of Arcelor’s plants in Karaganda for testing and crew training. The assembly process was carried out by Kazakh coal miners under Famur’s supervision as a part of an on-the-job training agreement.
Famur recommended the training for the Arcelor miners, as the new system was a completely new solution for them. During the FRTS-900 evaluation in Karaganda, the system was presented to and accepted by Arcelor’s management. As far as the Kazakh coal miners were concerned, all the initially proposed goals were achieved:
- The system is safer than previous solutions, as all miners are above the platform in a safe area;
- The new system is cheaper than comparable ones, though those are not as comprehensive solutions; and
- The system enables longwall assembly to be much more effective.
Presently, the FRTS-900 is successfully working in an ArcelorMittal underground coal mine in Kazakhstan.