1. In the case of face workings where props are used–
(a)the maximum distance between props in the same row shall be 1.2 metres;
(b)the maximum distance between adjacent rows of props shall be 1.2 metres;
(c)the sum of the distances between props in the same row and between adjacent rows of props shall not exceed 2.1 metres;
(d)bars shall always be used above the props where the extracted height exceeds 0.6 metres; and
(e)the maximum distance between the row of props closest to the face and the face shall be–
(i)where an armoured conveyor is used and persons do not normally work on the face side of the conveyor, 2 metres, and
(ii)in all other cases when filling or loading at the face has been completed, 0.9 metres.
2. In the case of face workings where bars are used–
(a)the maximum distance between adjacent bars in the same row shall be 1.2 metres; and
(b)bars should be advanced as soon as is practicable after extraction and set so that the maximum distance between the end of the bar closest to the face and the face shall be 0.4 metres.
3. In the case of face workings where powered supports are used–
(a)such supports should be advanced as soon as is practicable after extraction and set so that the maximum distance between the end of the beam closest to the face and the face shall be 0.5 metres;
(b)during normal production at any place where a machine is used which shears mineral to a depth exceeding 0.4 metres, the said machine must not be permitted to approach within 27 metres of any powered support which has not been advanced from the previous cut; and
(c)where an immediate forward support system is used, the supports shall be advanced–
(i)as close as is practicable behind the coal getting machine, and
(ii)in any event, no more than 10 metres behind the coal getting machine.
4. For the purposes of paragraph 3–
(a)“powered support” means a support which is advanced and set to the roof by mechanical energy;
(b)“beam” means that part of a powered support system designed to be set to the roof; and
(c)“immediate forward support system” means a system of supports designed to be advanced and set to the roof immediately after extraction by a coal-getting machine.
5. In the case of face workings where packs are used–
(a)the maximum width of roof exposed by the working of mineral since the completion of the last pack shall be 2.1 metres; and
(b)the waste edge parallel to the face shall be no more than 1.5 metres in advance of the front line of pack bounding that waste.
6. In the case of face workings where persons work or pass more than 0.9 metres beyond the front row of props or other supports, temporary supports shall be used and no person may work more than 0.9 metres from a temporary support.
7. In this Part, “face working” in relation to a working face at which supports are systematically withdrawn means all that part of the mine between the face and the front line of the packs, if any, or the last row of supports for the time being maintained whichever is further from the face and in relation to a working face at which supports are not systematically withdrawn means all that part of the mine between the face and a line parallel to it and 3.7 metres distant from it.