111. Development work.

1.    The dimensions of pillars and galleries, and the shape of pillars, formed in any seam or section shall be such as to ensure stability during the formation and extraction of pillars, and during the period between such formation and extraction.

2.    Save with the previous permission in writing of the Regional Inspector and subject to such conditions as he may specify therein, no gallery in a seam or section shall exceed three meters in height or 4.8 meters in width at any place.

3.    The pillars formed in any seam or section shall normally be rectangular in shape.

4.    The distance between the centers of any two adjacent pillars left in a seam or section shall not be less than that specified in the table below as corresponding to the depth of the seam or section from the surface at that point and the width of the galleries in the working in question.  

 

Table

Depth of seam from surface	Where the width of the galleries does not exceed 3.0 meters	Where the width of the galleries does not exceed 3.6 meters	Where the width of the galleries does not exceed 4.2 meters	Where the width of the galleries does not exceed 4.8 meters
	The distance between centers of adjacent pillars shall not be less than
(1)	(2)	(3)	(4)	(5)
	Meters	Meters	Meters	Meters
Not exceeding 60 meters	12.0	15.0	18.0	19.5
Exceeding 60 but not exceeding 90 meters	13.5	16.5	19.5	21.0
Exceeding 90 but not exceeding 150 meters	16.5	19.5	22.5	25.5
Exceeding 150 but not exceeding 240 meters	22.5	25.5	30.5	34.5
Exceeding 240 but not exceeding 360 meters	28.5	34.5	39.5	45.0
Exceeding 360 meters	39.0	42.0	45.0	48.0

 

5.    The Chief Inspector may by an order in writing and subject to such conditions as he may specify therein, exempt a mine or part thereof to form pillars in variance to that specified in the sub-regulations (3) and (4). 

6.    Nothing in sub-regulation (2), (3), (4) and (5) shall apply to workings in a mine made before 7^th September, 1926 and the following provisions shall apply to all workings made prior to said date, except during the extraction or reduction of pillars, -

(a)         if the distance between the centers of adjacent pillars is smaller than that specified in the table under sub-regulation (4), the pillars shall not be further reduced; or

(b)         if the distance between the centers of adjacent pillar is not smaller than that specified in the table under sub-regulation (4), the pillars shall not be so reduced as to render such distance smaller than –

(i)         the distance so specified; or

(ii)        any distance required in this behalf by the Chief Inspector; and

(c)         the height and width of the galleries shall not be further increased without the permission in writing of the Regional Inspector and subject to such conditions as he may specify therein.

7.    In the case of all workings, where in the opinion of the Regional Inspector the dimensions of pillars or galleries are such as to render that crushing of pillars or the premature collapse of any part of the workings is likely to occur either before or during the extraction of pillars, he may, by an order in writing, require such modification of the dimensions aforesaid in respect of any future working as he may specify.