Technical characteristics
| Parameters | М21.10-25 | М21.13-28 | М21.15-32 | М21.16-35 | |
| Section installing pitch, m. | 1,75 | 1,75 | 1,75 | 1,75 | |
| Quantity of hydraulic props in the section, pcs. | 2 | 2 | 2 | 2 | |
| Resistivity of the support, kN/m², not less | 700…990 | 840…980 | 840…980 | 1055…1145 | |
| Section resistance, kN, not less | 6700…7300 | 6950…8150 | 6950…8150 | 8160…8865 | |
| Average ground pressure, MPa, not more | 2,05 | 2,2…2,6 | 2,2…2,6 | 2,0 | |
| Operating pressure, MPa | 40 | 40 | 40 | 42,5 | |
| Section advance pitch, m. | 0,63; 0,8 | 0,8 | 0,8 | 0,8 | |
| Section weight, t. | 19,5 | 22 | 24 | 26,5 | |
The powered support M21 consists of two-props sections with four-chain linking system of
the basis with the barrier; the rigid-linked ceiling, equipped with the flap visor with
enhanced effort and device for face keeping (from H ≥ 2.5 m). To adjust the section in the
seam plane and to protect the workspace under the support against small stuff extension
boards and pusher-jack (with or without landside) installed onto one side are used in the
section. It is possible to reinstall boards and pusher-jack onto another side, also to
manage them independently separately from both sides of the section.
The whole operating range for small and medium seam thickness is offset by a number of
sections with an installing pitch 1.75 m. Also, quantity of sections in the
longwall and time of their extension are reducing in comparison with the supports 1М21.