Underground construction

• Pages: 282-303

32. Underground construction

32.1. General provisions

32.1.1. Tunnelling operation should be carried on in accord-

ance with plans approved by the competent authority.

32.1.2. All occupied workplaces underground should be

inspected at least once in every shift.

32.1.3. Places occupied by solitary workers should be inspect-

ed at least twice in every shift.

32.1.4. At least once in every week, thorough inspections

should be made of all machinery, equipment, structures, supports,

roadways, means of egress, magazines, medical facilities, sani-

tation and working places.

32.1.5. All workers should be withdrawn from underground

workings if:

the ventilation fails; or

other imminent danger threatens.

32.1.6. Parts of underground workings found to be dangerous

should be fenced off.

32.1.7. A telephone system should be maintained from the

vicinity of the face of underground workings to the surface with

stations at intermediate workplaces.

32.1.8. In underground workings that are Wet, the workers

should be provided with waterproof clothing and boots.

32.1.9, In tunnels and other underground workings where

an explosive mixture of gas such as methane and air may form,

operations should be carried on in accordance with national

or other official regulations applying to gassy mines.

32.1.10. In these cases referred to in paragraph 32.1.9, in

particular:

(a) all electrical equipment and conductors should be flame-

proof or intrinsically safe;

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Underground construction

the current should be cut off from all electrical equipment

and conductors when the content of flammable gas in the

general body of the air exceeds safe limits;

no blasting should be done at any place where the content

of flammable gas in the atmosphere exceeds safe limits;

suitable gas detectors and gas alarms should be provided;

the atmosphere should be tested at suitable intervals in every

shift;

all workers should be withdrawn from the underground

workings when the content of flammable gas in the general

body of the air exceeds a percentage to be determined by the

competent authority; and

no worker should be allowed to carry matches or cigarette

lighters underground.

32.2. Shaft sinking

General provisions

32.2.1. Every shaft not sunk through solid rock should be

cased, lined or otherwise made safe.

32.2.2. Shuttering for masonry lining of shafts should only be

removed gradually as the masonry progresses.

32.2.3. As far as practicable, workers employed in sinking

shafts should be protected against falls of objects.

32.2.4. Workers employed on sinking shafts should be provided

with staging, scaffolds or cradles from which they can work safely.

32.2.5. Staging, scaffolds and cradles should, if necessary for

the maintenance of adequate ventilation in the shaft, be provided

with grids or other suitable devices.

32.2.6. As soon as practicable, the shaft top should be protect-

ed by adequate fencing, or guard-rails and toe-boards and gates.

32.2.7. When a shaft is being sunk through water-bearing

strata, adequate means of escape from the bottom should be

provided.

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