Frontal mining apparatus

FRONTAL MINING APPARATUS (EN: frontal unit; DE: Frontaggregat; FR: complexe d'abattage à attaque frontale; ES: complejo para el frente de arrangue; RU: агрегат фронтальный) is the combination of the mining machines and mechanisms, which are structurally and kinematically linked together by all the parameters, which are performing the extraction of the stratified minerals in the direction of the (face) front plane of the (longwall) clearing stope.Frontal mining apparatus

The working instrument of the frontal mining apparatus is moving at the same time in the flank (along the face of the stope) and in the frontal directions. The frontal mining apparatuses are used at the coal mines in the (longwall) clearing stopes of the seams with the sustained bedding. They have been created in the USSR in the 50's for the first time for the conditions of the slightly inclined seams (the frontal mining apparatuses of the A2, A3 types), in the 70's for the steep seams (of the ASCH type). There were working in 1980 in the USSR the 65 frontal mining apparatuses (in the steep seams).

The frontal mining apparatus comprises the extraction machines, the equipment for the delivery of the coal, the mechanized sectional roof support equipment (the sections move in the alternating sequence), and other equipment, which ensures the continuous, automatic and simultaneous extraction of minerals, the fixation of the working space of the clearing stope, and the control of the roof. By type of the extraction machines, the frontal mining apparatuses are subdivided into the four main groups: the first group includes the frontal mining apparatuses, which are equiped with the carriages (with cutters and scrapers), which are continuously moving in one direction (the ring shaped ploughs and the conveyor ploughs), the second group includes the apparatuses with the ploughs of the forth and back movement, the third group includes the apparatuses with the combined cutter-loaders, the fourth group includes the apparatuses with the swinging breaking drums, which are fixed on the each section of the mechanized roof support equipment.

They are using in the USSR the frontal mining apparatuses with the screw shaped ploughs and stope conveyors (the frontal mining apparatuses of the AMS, AMSK, ASMB types), with the coal ploughs of the shuttle action and stope conveyors (SA, F-15, ASKB), with the ring shaped ploughs on the carriages (A2, A3, AK3) and the conveyor ploughs (ASCH, ANSCH, 1ASCHM, ADK, AKD2). There have got the greatest usage in the USSR the frontal mining apparatuses of the first group, and somewhat lesser of the third group (Table and Figure).

The main advantages of the frontal mining apparatus (in comparison with the mechanized clearing complex systems) are: the non-existence of the auxiliary operations at the ends of the longwall stope, the greater performance, and the higher level of the automation. The disadvantages are: the complication of the directional driving along the coal-rock contact and of the changing of the length of the frontal mining apparatuses, the lesser manoeuvrability. It is expected to expand the area of the usage of the frontal mining apparatuses on the account of the further improvement of the working instruments and the control, of the mechanized roof support equipment. It is planned to equip up to 75-80% of the stopes at the steep seams of the Donbass with the frontal mining apparatuses of the ASCH type.

The type of the apparatus The thicknes of the seam, metres The angle of the dip of the seam, degrees The length of the apparatus, metres The load bearing capacity of the roof support system, tonnes per square metre The calculated productivity, tonnes per minute
ASCH(1) 1.4-2.2 45-90 40 15 1.5
1ASCHM(1) 1.2-2.2 50-90 40 15.6-17 less than 2.5
ANSCH(1) 0.7-1.3 40-90 40, 60 19 1.5
ADK(1) 1.2-2.2 45-90 60 11.7 less than 2.5
AK3(2) 1.6-2.5 0-90 50-120 57 less than 12.5
AKD2(3) 0.8-1.45 35-90 120 21-48 less than 2.5
SA(3) 1.5-2.0 less than 8 60-100 29 less than 2.5
AMSK(4) 1.7-2.3 35-90 more than 6 40-67 less than 1.5