TCVN 5178-1990

Internal Technical Document

Group A

Entire obligatorily applied Standard

Technical safety regulations for open-pit mining and processing

This Standard replaces QPVN 22 : 1981.

This Standard provides technical safety measures of open-pit mining and

processing in enterprises, construction sites, cooperatives etc. professional or

non-professional mining or processing by economic sectors of ministries,

branches and local agencies, including army units doing business (common

called as mining and processing establishment).

This standard does not apply to establishments mining pit stone and

processing splitting stone.

1. General regulation

1.1 Mining and/or processing are only carried out when obtaining license of

provincial, city or special zone People's committees. Design of mining should

be approved by competent authority and agreed in labor safety in accordance

with Appendix of this Standard. Content of the design is subject to regulations

of this Standard.

1.2 Mining and processing enterprises should base on this Standard to build

safety process for trades or separate in part to train workers, cooperative

members, soldiers (called as workers) related to trade they follow. Results of

examining their knowledge should be done in minutes by with signature of

trainee. Workers alone who make drilling and explosion must be male ones

aged between 20 and 50 with medical certificates full of health for at the top

work and who trained, checked for attained requirement, later certificate of

explosive use.

Construction Dept. - Internal translation only (TCVN 5178:1990) 1


Annual medical check-up must be done for workers and personnel who

engage in mining and processing in accordance with the regulation of

Ministry of Public Health.

1.3 Responsibility of a mining enterprise is as follows:

- Build paths going up and down mountain for convenience and safety to

workers. If slope of paths are more than 30, hand rail should be necessary.

- Means of transport should be provided in security in accordance with

regulation of Vietnam Registration in current waterway transport in case

workers have to go to work by passing through river in construction level

ground.

Matters such as labor hygiene, industrial hygiene, labor protection should be

implemented strictly in accordance with current regulations of State,

especially matters as follows:

- Positive measures of preventing dust caused by drilling and mine explosion,

crushing and screening are required.

- Worker accommodation must be at least 500 metres far from manufacturing

and processing areas. This location does not lie at the end on main direction

of wind of year.

Persons who are responsible for technical guidance in mining and processing

enterprises have to meet the following standards:

- Trained from mining technical or material exploitation colleges or secondary

education schools.

- Experienced and skilled workers in mining are preferred as special case,

however, before promotion, they have to be provided further training in

mining technique and labor safety, as well as different safety regulation

standards related.

Before assignment at every shift, commanders (leader of group, manager etc.)

have to take note on assigning book or assigning note to every worker or



production group, in which labor safety measure has to be shown in detail,

with signatures of assignor and assignee.

Before arranging works to workers, official who directly supply concrete

guidance in production has to have specific consideration at site that is in

safety situation or not for the arrangement.

Workers who are newly recruited for mining work have to be trained in

professional skills and labor safety according to the regulation of State.

Workers have to carry full labor safety equipment at work, abide by strictly

safety regulations at the working place and related sections. When dangerous

signs are found, workers have to take precautions and inform immediately

official in charge for timely measures settled.

Besides regulations indicated in this Vietnam Standard, mining and

processing enterprises have to abide by strictly Vietnam standards and

branch's standard (TCN) related. Especially TCVN 4568 : 1988: Safety

Regulations for explosive maintenance, transport and usage.

Technical safety for open-pit mining

1. Preparation stage.

1.1 Before opening seam, it's required to:

- Clear trees or hurdles in scale of opening layer.

- Move houses, works within dangerous area due to mine explosion, rolling

stone.

- Build roads to transport equipment up to mountain and for circulation.

- Prepare waste field and road for transport stone and wasted earth.

- Excavate ditch for drainage and bank for prevent water running into mining

site if a mine exploited deeper.

2.1.2 Process of basic construction for preparation of mining has to be carried

out in accordance with approved design. If any change made to the design, it

must have approval of competent authority.

2.2 Safety requirement before opening layer:



2.2.1 When mining on the top or depth of any mountain, creation of layers is

required. Size of layer must be subject to real condition and working capacity

of equipment to be used.

2.2 If slope of mountain side is larger than that of natural sliding of stone and

earth, exploiting layer must be opened from above to down. If it is smaller or

equivalent, opening of layer from lower up to above is necessary. (figure 1).

: Slope corner of mountain side.

: Natural sliding corner of earth and stone.

Figure 1

2.2.3 Height of mining layer (H) - (figure 2) must guarantee in accordance

with design but not exceed:

a) For manual mining:

In special case of the geological structure of broken stones is stable, stakeout

corner of stone bed is directed toward inside of mountain (figure 3) approved

by organ in charge, then it's permitted to cut throughout layer, but the height

of the layer is not more than 15 metres.

b) For mechanical mining:

- Double 1.5 times maximum height of excavating when using straight bucket

excavator.

- One time maximum height of excavating of excavator when excavating in

the position of soft earth and stones without mine explosion.

- 20 metres if mechanizing total mining process.

- 30 metres when exploiting identical blocks of stones, with added safety

measures and permission of organ in charge after obtaining agreement of

local safety inspection body.



2.2.4 The slope of mining layer side () (figure 2) does not exceed:

- Natural slope corner of earth and stones if they are kind of spongy and loose

stones.

- 60 for soft earth and stones but stable.

- 80 for solid earth and stones.

2.2.5 Width of working layer surface (B) (figure 2) is subject to the design but

it must be wide enough to place necessary equipment and make the way of

minimum one metre.

- If manual mining to be applied, without transport on the surface of layer,

then the width of layer surface is not less than 1.5 metre.

- If manual mining to be applied, with transport by hand trolley, then the

width of layer surface is not less than 3 metre.

- If mechanical mining to be applied, the surface of layer has to guarantee

fully for mining and transport equipment for safety operation.

2.2.6 Incline corner of layer surface () - Figure 2.

- If manual mining to be applied, it is not more than 15.

- If mechanical mining to be applied: Calculated on balance stableness of

layer surface and equipment during its operation on the layer. Roundabout

ways must guarantee super height according to regulation on the road bed of

mechanical vehicles

2.2.7 Before new layer is cut, checking layer side and surface, make sure that

a distance of 0.5 metre from surface of layer without stones or any object to

avoid falling into lower layer.

2.3 Mine bank protection.

2.3.1 Layers mined up to mine border have to be retained protecting layer

surface (C) and corner of mine bank () (figure 4) in accordance with design,

however, the corner of mine bank is not more than natural sliding corner of

earth and stones.

2.3.2 Slope corner of non-mined layer side is not more than 60.



If stone bed cut, weathered friable or stakeout corner of stone bed is less than

60, slope corner of non-mined layer side is not more than natural sliding

corner of those earth and stones.

2.3.3 The height of non-mined layer with overlapping of multi mining layers

is not more than 30 metres.

2.3.4 Width of protecting layer surface is not less than 1/3 height between two

layers. Ditch for drainage running alongside protecting layer surface is

required.

2.4 Waste ground.

2.4.1 Waste ground should be provided at mines. Houses and works within

area of waste ground should be moved to safety places. Enclosures or no

travel signs must be set up in dangerous areas.

2.4.2 If waste ground placed in mountain creek or valley, system of flood

drainage must be set up prior.

2.4.3 Waste ground placed at part of unstable earth and stones, it's necessary

to make a slope running inside at least 2. Outside bank of waste ground is at

least 0.5 metre high, 0.7 metre wide.

2.4.5 In case waste earth and stones transported by trolley, the following

requirements must be abided by:

- Outside rail must be 20-30mm higher than inside rail.

- A round way running inside waste ground at the end of the rail is necessary

with barrier. A slope from the top of blind way to backward within about 100

metres must be set up (the slope is at least 5/00 to the inside).

- Signs must be placed at barriers, with lighting at night.

- Official in charge at construction site is responsible for check, written

acceptance with attained requirements, then allow trolley to dump waste earth

and stones at that way after every way movement.

2.4.6 Waste ground should be cleared, leveled, with lights provided at night.

2.5 Safety requirement for prizing and unraveling stones on the layer.



2.5.1 Safety belt is necessary for workers working on slope layer side of

above 45 and at the height of 2 metres above from the layer foot, at high and

dangerous cliffs, or near edge of layer. The safety belt must be fastened

tightly into stake, stakes must be pitched into stone with a depth of at least

0.40 metre. In case safety belt is 2 metres longer, subordinate stake is

necessary.

2.5.2 Use of two safety belts for a stake or two persons share a safety belt is

prohibited.

2.5.3 If the way to working place by climbing, the way must be set up with

footstep and banister, and transitional part set at every 10 metres, its slope

of this way is not more than 40. Use of safety belt for climbing up or down is

prohibited.

2.5.4 Watchers should be assigned while prizing and unraveling stones on the

layer in case circulation of people and vehicles.

2.5.5 Assignment of workers working on the upper and lower layer, or

working in the top of mountain and foot of mountain at the same time of line

is prohibited.

2.5.6 Workers of prizing and unraveling stones on the same layer must be

assigned at the distance of at least 6 metres each. Finishing first prizing and

unraveling on the top layer then on the lower layer.

In case a worker who has difficulty in prizing and unraveling stones and he

can't settle by himself risky stones, a timely notice made to official in charge

for timely settlement.

2.5.7 Prohibitions:

- Throw wagon into the lower layer from the upper layer.

- Pitch wagon on the layer mirror or leaning on the layer mirror while

working.

2.5.8 After finishing prizing and unraveling stones and all workers on the

upper layer having gone down, official in charge makes direct check for



safety, then prohibited orders shall be allowed to taking off in accordance

with regulation of item 2.5.4.

2.6 Technical safety for drilling and mine explosion.

2.6.1 General requirements:

2.6.1.1 All mining establishments that wish to use frequently or temporarily

explosives must ask for use permit from organ in charge. Later, before using

it is necessary to make registry with technical safety inspector body of State

and provincial police body for agreement of labor safety conditions and social

security.

2.6.1.2 Bore holes and explosion should be carried out in accordance with

design or permit already approved, indicated as follows:

- Chamber mine explosion should be made in accordance with design

approved by higher level and agreement of technical safety inspector body

and fire control body of provincial and city levels.

- Mine explosion of large bore holes should obtain permit specific for every

stage with signature of the leader of unit.

- Mine explosion of small bore holes, pressing and pocket-made mine

explosions should obtain passport with signature of the leader of unit, or set

up permit for every stage of explosion with signature of chief group or

commander of drilling and explosion.

The passport of drilling and explosion must include the following content:

a) Diagram of bore holes, bore hole quantity and depth, volume of explosive

and explosive means clues, necessary length of clue for bore holes,

hardness and nature of earth and stones (f).

b) Diameter of dangerous area of a mine explosion is as per appendix 3 of this

Standard.

c) Shelter position of miner and worker during explosion. Safety position for

equipment is provided.

d) Position for guard stations.



e) Result of an explosion.

2.6.1.3 Unit permitted mine explosion should give a prior notice of first and

daily explosion time, limit of dangerous area and warning signs to local

authority and police, and neighboring units before carrying out the first

explosion at permitted location.

2.6.1.4 During explosion drilling, any necessary change made to parameters

of the passport have to obtain the agreement of passport approving official.

2.6.1.5 Workers who work relating to use and maintenance of explosive must

be provided training according to appendix 4 of TCVN 4586:1988. Local

professional council is responsible for training, checking, granting explosive

use certificate etc. For cooperatives and army units doing business that

permitted to use explosive, their miner should be trained, checked and granted

explosive use certificate and explosive warehouse keeping certificate by

Service of Labor, Invalid and Social Affair.

2.6.2 Safety requirements of stone drilling machine operation.

2.6.2.1 Big drilling machine

2.6.2.1.1 Before using the drilling machine, it's necessary to chock firmly the

machine with dedicated chocking object. Use of stone for chocking is

prohibited. Transmission parts of the machine should be covered tightly.

Surface of the machine working must be stable.

2.6.2.1.2 Rod of drilling machine should be lowered before moving, except

for moving on the level layer surface with the length of less than 100m of the

way and no passing under electric lines. When lifting and lowering the

drilling rod, person who is not on duty should leave there.

2.6.2.1.3 Drilling machine operator's responsibility:

- Check the machine before starting.

- To be always present at working place. Any person who is not on duty is not

allowed to stand on the machine while it is operating.

2.6.2.1.4 Repair or greasing while the machine is operating is prohibited.



2.6.2.1.5 Lifting cable of drilling machine should be checked at least one time

a week, if there have about 10 percent of cable fibre volume of twisted step

broken to be found, a replacement is necessary. Cable situation checking and

watching book is required.

2.6.2.1.6 Power-operated drilling machine whose body and electric motor

should be ground contacted in accordance with TCVN 4758:1989.

It's only allowed to repair electric parts of drilling machine when the power

supply is cut off and a warning table "No contacting electric" is

recommended. Key of interruptor cabinet should be kept by electrician.

2.6.2.2 Hand pneumatic pressed drilling hammer.

2.6.2.2.1 Worker operating this hammer should stand firmly on the layer

surface. Drilling executed on the dangerous mountain side is not allowed, in

case of drilling to open layer, a standing position of at least 1 metre width

should be created.

2.6.2.2.2 Suspending large rocks should be prized up before drilling. Drilling

made at places that have possibility of rockslide is prohibited. Measure of

preventing dust during drilling is required.

2.6.2.2.3 Drilling operator should wear tidily. During opening bore holes, the

machine should be operated slowly and gradually increased in speed up to

stability. Using hand to keep wagon while opening bore holes is prohibited.

2.6.2.2.4 Two workers serve in a shift for a drilling hammer. Using hands to

keep the hammer during drilling is recommended, use of hands prohibited.

Drilling wagon must have appropriate length how so that drilling hammer

placed chest range of operator.

2.6.2.2.5 Press pneumatic conducting line from the top to down in line of

drilling should not be installed. Be careful of falling rock during moving

drilling hammer and conducting line.

2.6.2.3 Air compressor.



2.6.2.3.1 Any establishment that use air compressor should abide by current

"Technical safety regulations for pressure containers".

2.6.2.3.2 Fixed or mobile air compressor should be placed on even and flat

foundation and chocked firmly. Air compressor placed near exploding or fire

easy agents is prohibited.

2.6.2.3.3 Operator of air compressor must watch its frequent temperature,

pressure, noise etc. It must be stopped when:

- Over-pressure allowed.

- Non-working of safety valve.

- Over-temperature allowed.

- Abnormal noise taking place.

2.6.3 Safety requirement for maintenance, transport and use of explosive.

2.6.3.1 Safety requirement for maintenance, transport of explosive.

2.6.3.1.1 Establishments using explosive should set up warehouse in

accordance with regulation of appendix 2 of this Standard. Storing explosive

in dwelling house and/or working house is prohibited. Excessive explosive

must be returned to warehouse.

2.6.3.1.2 A miner is able to carry within 12kg of explosive and explosive

parts with him. Primer is prohibited to keep in pocket.

2.6.3.1.3 Explosive bearer is not allowed to halt or put explosive in crowded

places or position in drilling. Use fire near position placing explosive is

prohibited.

2.6.3.2 Safety requirement for use of explosive.

2.6.3.2.1 If there are many mining units operating near one another, they have

to set united time of explosion and give one another notice location and

courses of explosion, as well as warning signs before explosion.

2.6.3.2.2 Watchers must be assigned before setting off mine. They have to

sign after conducted. They are not allowed to leave their watching position

but receiving safety sign.



2.6.3.2.3 Mine explosion with delay cord.

2.6.3.2.3.1 Using sharp knife to cut delay cord. Delay cord and primer

connected together by the following methods:

- For primer case made of metal: Using dedicated pincer only to clamp primer

mouth to the cord. Clamping of primer made to section of containing

explosive is prohibited.

- For primer case made of paper: Using thread or adhesive tape to roll round

primer head up to equivalent diameter of primer is allowed only, later delay

cord is inserted slightly into primer mouth, then use thread or band to roll

tightly primer mouth.

2.6.3.2.3.2. Prohibition for connecting delay cord to primer:

- Press strongly or revolve.

- Use teeth or any object to fix primer and cord.

- Cut delay cord when have already pressed the primer.

2.6.3.2.3.3 Length of delay cord should be calculated enough to secure safety

of miner. In every case, length of a mine fuse is not less than 1 metre and

delay cord outside mouth of mine hole is not less than 25 centimetres.

2.6.3.2.3.4 Use of mine fuses of length more than 10 metres is prohibited. If

the length of mine fuse is more than 4 metres, two fuses should be used and

burn at the same time.

2.6.3.2.3.5 In case of five fuses or more burnt in an explosion, the check fuse

should be used to check time of consumption in burning fuses. Delay cord of

check fuse is shorter than mine burnt first is 60 metres but not shorter than 40

metres. Check fuse must be burnt first, not nearer than first fuse is 5 metres

and not allowed to place in retreating way of miner to safety area. Miners

must immediately leave mine field to safety location or shelter after check

fuse burnt.

2.6.3.2.3.6 Worker in charge should count every explosion. If he can't count

or when any mine hole does not explode, then 15 minutes later miner can go



into for checking. Unexploded mine holes must be marked and warning sign

"persons with no function to access prohibited".

In case there have no unexploded mine, 5 minutes later from last explosion,

miner is allowed to enter mine field for checking.

2.6.3.2.3.7 Use of two kinds of primer and two kinds of delay cord for an

explosion are not prohibited.

2.6.3.2.4 Explosion by electric primer.

2.6.3.2.4.1 All kinds of electric primers should be checked in resistance by

dedicated resistance meter before using. Person who is in charge of checking

primer shall be official or miner who is conducted the way to use meter and

method of gauging. Every such checker is not allowed to have more than 100

primers. Gauging must be made in metal pipe or behind a sheet of wood of at

least 10cm thickness during gauging.

2.6.3.2.4.2 Electric current of electric primer's resistance meter and electric

network of explosion is not more than 50mA. Electric current should be

checked in quarters after each of replacing of batteries.

2.6.3.2.4.3 Explosion wire must be insulated one and have two conducting

wires. Use of water, earth, water pipe etc to replace one of two conducting

wires are prohibited. Joints must be covered.

2.6.3.2.4.4 Use of mine explosion machines, electric network or lighting

network as explosion starter is allowed. Interruptor of electric or lighting

network input must be kind of dedicated one for explosion, the interruptor

should be placed in case or cabinet locked.

2.6.3.2.4.5 The key of mine explosion machine or interruptor cabinet must be

kept by explosion conductor during the preparation till explosion.

2.6.3.2.4.6 When contacting electric or turning hand-level of mine explosion

machine, if mines do not explode, miner must disconnect two heads of main

conducting wires from power source, connect two heads together, lock mine



explosion machine or interruptor cabinet and keep the key. Later carrying out

check the reason of mines unexploded.

In this case, he must wait at least 10 minutes depending on style of electric

primer used, then allowed to enter mine field for check.

2.6.3.2.5 Settlement of unexploded mines

2.6.3.2.5.1 The settlement of unexploded mines should be carried out by

miners under the supervision of official in charge at mine field. Persons who

are not on duty should leave dangerous area.

2.6.3.2.5.2 Drilling to unexploded mine holes or using any object to take out

or take primer out of mine hole is prohibited.

2.6.3.2.5.3 In case explosive in mine hole blaze up with no explosion only,

use of stick or any object to take it out is prohibited. Waiting 30 minutes later,

recharge explosive shall be allowed. A bar of clay or some sand is put into

bottom of mine hole before charging explosive.

2.6.3.2.5.4 In case of explosion, delay cord does not burn, re-burning allowed

if it is not yet burnt. In case pressed mines do not explode, use of hands to

scoop up above layer of earth is allowed, later replacing another mine for

explosion.

2.6.3.2.5.5 Adding explosive outside unexploded mine hole mouth to fire for

stimulating explosion to shallow mine holes and clue of less than 0.4m.

2.6.3.2.5.6 In case this method of fire is impossible, an another hole

paralleling with unexploded mine hole must be drilled, distance between two

hole is more than 0.3m for small drilling hole and 3m for large drilling hole

for charging explosive to fire for stimulating explosion.

2.6.3.2.5.7 After re-firing or firing for stimulating explosion, the conductor in

charge of settling unexploded mine must check if explosive in unexploded

mine hole exploded up or not.

If primer left, scattering explosive should be collected then arranging workers

for work.



2.6.3.2.5.8 When exploding mine with electric primer, but electric primer is

out of order, if two heads of electric wire are exposed to be found,

immediately connect these two heads together then conducting following

works to settle it.

2.7 Technical safety for excavation and leveling.

2.7.1 General requirement:

2.7.1.1 Operator of excavator and leveling machine must meet sufficiently

requirements as follows:

- Certificate of enough health for operating issued by medical organ.

- Provided training for operation of such machines.

- Certificate of education and checking with attained requirements in technical

safety confirmed by director of unit.

2.7.1.2 Excavator and/or leveling machine operating at night must guarantee

sufficient lighting.

2.7.1.3 Excavating and/or should be executed subject to passport already

approved and signed by director or leader of unit.

2.7.2 Safety requirement for use of excavator.

2.7.2.1 Excavator must be equipped fully with signals. Operator has to give

signs to people around before his working. No one allowed to stand within

range of excavator's operation.

2.7.2.2 Excavator operating under the foot of layer higher than the regulation

height, layer with vaulted entrance or layer with persons working and

rockslide is prohibited.

2.7.2.3 Operator should notice earthen and rocked wall being excavated. If

there is a sign of landslide, the machine must be moved out to safety location

and a notice given to conductor for measures of settlement. A retreat way is

always set up available.

2.7.2.4 Prohibition while loading earth and stone into truck:

- Moving bucket to cabin.



- Distance from bucket to the bottom of body or surface of earth and stones on

truck exceed 1m in height.

- Touching bucket to body.

2.7.2.5 If excavator has no protecting sheet in cabin, operator must leave

cabin out of revolving of excavator. Operator has to blow the horn for

warning before and after dumping.

2.7.2.6 Distance between two excavators working is not less than total radius

of largest working of these excavators plus 2 metres.

Arrangement for an excavator working on the higher layer and an excavator

on the lower layer in vertical is prohibited.

2.7.2.7 Soft electric cable leading to excavator does not exceed 200 metres,

rack for cable required, prohibited that:

- Using bucket of excavator to move electric cable.

- Placing cable into mud or humid earth or let transport vehicles going across.

- Turning bucket above electric cable. If it's unavoidable, measure of

protecting cable from falling of stones should be set forth.

2.7.2.8 Standing to excavate under power transmission line is prohibited.

During excavating or moving, distance of any point of excavator leading to

nearest electric wire must be more than:

1.5m for power line of 1KV

2m for power line of more than 1kv 20kv.

4m for power line of 35kv - 110kv.

6m for power line of 220kv.

2.7.2.9 Moving excavator at night or at slopes exceeding standard fixed by

manufacturing plant, is prohibited.

2.7.2.10. Maintenance or repair done to excavator during its operation is

prohibited. Bucket should be lowered into the ground before repairing.

2.7.2.11 When stopping working, excavator should be moved to safety

location and its bucket lowered into the ground.



2.7.3 Safety requirement for leveler use

2.7.3.1 While the leveler operating, prohibit:

- Repair or correct cable of leveling blade or stand on the leveling blade.

- Stop the leveler on the non-stable foundation and stop when many earth and

stones on the leveling blade left.

- Drive the leveler close to edge of layer.

2.7.3.2 Watcher is necessary while the leveler operating at the foot of layer or

close to edge of layer, if any landslide is found, the leveler should be moved

timely to safety location and resumed its operation only when the landslide

settled completely.

2.7.3.3 The leveler is prohibited to operate in the dangerous area of excavator

when it is operating.

2.7.3.4 The leveler is prohibited to excavate or prize stone or move larger

rocks against allowed capacity of leveling.

2.7.3.5 The leveler should be stopped with its blade lowered before repairing

and greasing.

Leveling blade should be put on stable sheets of wood before checking and

repairing leveling blade.

2.7.3.6 When leveling up, maximum incline corner of leveling ground is not

more than 25, and less than 30 when leveling down.

2.8 Safety requirement for in-mine stone transport

2.8.1 Transport by railway:

2.8.1.1 Structure of in-mine railway is subject to design approved already and

in accordance with current regulations of Vietnam railway.

2.8.1.2 Signal posts and barriers should be set up at conjunction of railway

and pedestrian road and other roads.

2.8.1.3 Speed of the train cars running inside mine is defined by an

establishment and based on technical characteristics of train cars used,

structure of railroad and condition in locations.



2.8.1.4 Train cars are not allowed to stop and block entrance, in special case,

if it wants to stop, it should be detached into two sections to give a space with

the length at least equivalent to two railroad cars and chocked in two sides.

Climbing or going across below railroad cars or locomotive is prohibited.

2.8.1.5 Overloading is prohibited for railroad cars.

2.8.1.6 When railroad cars pressed together, a signal worker should sit on the

first railroad car or stand to operate at location how to easily see and safety

for operator. The operator must always blow the horn and abide by signals of

conductor. Oral commands or signals are subject to current regulation of

Vietnam Railway. In case such signals are not clear, operator should consider

it signal of stopping train.

Sections of refuge and around-the-time watching stations should be set up at

slopes of above 5/00, its length is more than 1km. Safety barriers should be set

up at the end of refuge way.

2.8.1.7 Pressing railroad cars together by using human power to push from

behind. It's only allowed to press one railroad car a time.

2.8.1.8 Brake used when railroad cars are stopped and chocked firmly.

Railroad cars with hooks opened have to also be chocked firmly.

2.8.1.9 Railroad cars without shock absorbers or shock absorbers broken

down are prohibited to use.

2.8.1.10 When train do not stop completely, prohibit:

- Hook or unhook railroad cars.

- Jump on or off railroad cars and locomotive.

2.8.1.11 Carrying people on saucer cars and goods cars is prohibited.

2.8.2 Transport by truck

2.8.2.1 Truck road should be built as per design and subject to current

standard of transport branch.

2.8.2.2 Speed of truck on sections of road within enterprise should be defined

by establishment but not contrary to current general regulation for road



transport. Trucks of another establishments that wish to enter mine area have

to obtain permission of mine leadership board after necessary requirements

guided to drivers.

2.8.2.3 It's not allowed to drive close to edge of layer without signal worker.

2.8.2.4 Prohibit:

- Carry people on the body of dump-truck or loading truck.

- Any one who sit on dome or cling outside truck, at footstep during truck

driving is prohibited.

- Carry people and explosive or inflammable agents in the same truck.

2.8.2.5 Trucks must stop out of operating range of excavator while waiting in

turn for loading stones. Trucks are only allowed to enter after receiving signal

of excavator operator.

- Trucks are only allowed to leave after receiving signal of excavator

operator.

2.8.3 Transport by conveyor:

2.8.3.1 Conveyor system should be equipped with signal while starting and

equipped with auto-stop system to material pouring machines into conveyor

once conveyor has break-down.

2.8.3.2 The conveyor is not placed so slope against standard and transported

oversize stones fixed by manufacturer.

2.8.3.3 Conveyor placed in a slope of more than 80 must have auto-brake

part of good working condition.

2.8.3.4 Transmission parts of the conveyor should be equipped with case or

defense net. Operator is only allowed to conveyor working when cases or

defense net installed fully.

2.8.3.5 When the conveyor is placed at 1.5m higher than ground surface,

defense fence must be set up at passing places or people working under. In

case the conveyor is long necessary to repair and check, overpass and firm

banister are required.



Conveyors that require persons working and passing at two sides of

conveyors, large ways of at least 0.75m should be set up and safety standing

position for working. Conveyor placed above should have banister outside

way.

2.8.3.6 Conveyor operating at night should be equipped with lights along

conveyor, control panel and position of pouring materials.

2.8.3.7 Safety regulation and operation process should be provided at control

panel and position of pouring materials.

2.8.3.8 For mobile conveyor, measure to prevent overthrowing before moving

it.

2.8.3.9 Prohibit:

- Repair or re-stretch conveyor while it is operating.

- Transport tools, devices on the conveyor.

- Go passing, step across or stand or sit on the conveyor even when it is not

operating.

- Operate conveyor when its signal is out of order.

2.8.4 Manual transport

2.8.4.1 Transport by improved cart.

2.8.4.1.1 The cart must stop at even and flat location when stones loaded,

stone loading workers are not allowed to stand close to two cart wall.

Stones should be arranged tidily, not allowed to arrange higher than cart wall.

2.8.4.1.2 Loading carts must be at a distance of at least 5m. When going down

slope, carts should turn round and drawing from the front is prohibited.

Take precautions of stone falling while carts are going up slope.

2.8.4.1.3 The way for carts must be wide enough to give way.

2.8.4.2 Transport by hand trolley.

2.8.4.2.1 Tip cart railway must be set up in accordance with the design and

notice that:



- A large path of at least 0.75m should be set up at two sides of tip cart

railway. It's not allowed to place materials that cause blockage to this path.

- Slope of tip cart railway is not larger than 8/00

2.8.4.2.2 Trolley should be chocked firmly before stones loaded. There is a

balance of stone arrangement such as large stones arranged beneath.

2.8.4.2.3 For trolleys of loading capacity of 1 tons and more, there are at least

two workers to push it up.

2.8.4.2.4 Worker who pushes trolley must always follow closely and control

speed. In case any trolley with no brake should be chocked firmly with

chocking bar of at least 1m length for necessary use. Distance between two

trolleys running should be minimum 10m.

2.8.4.2.5 In case a trolley runs off the rail, its trolley operating worker must

inform immediately trolley operating worker of next trolley, at the same time

leaving road bed at once.

2.8.4.2.6 Prohibit:

- Stand at the front to draw or brake trolley.

- Let trolley running freely

- Stand or sit on the shock absorber or on the trolley while operating.

2.8.4.3 Transport by carrying on shoulder and using hands.

2.8.4.3.1 Road for stone carrier must be even and flat, if there have a slope of

above 30, footstep should be set up. If the road is slippery, anti-sliding

measure should be applied.

2.8.4.3.2 Make sure that shoulder poles, bamboo frames and baskets should

be checked before carrying.

2.8.4.3.3 When carrying stones through ditch, canal etc. a bridge of at least

6m width with firm banister should be set up.

2.8.4.3.4 Take precautions to crack stones while carrying.

2.9 Safety requirement for using electric in open-pit mines.



2.9.1 An establishment should own electric supply plan in which position of

transformer, electric distributing cabinet and electric consuming devices

should be indicated.

2.9.2 Connecting and cutting off power supply for repair if any, a connecting

and cutting off note is required in accordance with regulation sample. A

warning post read "No connect power, person working" is hung at cut-off

interruptor.

Workers only is in charge of repairing that electric system or official gives

direct command is allowed to re-connect electric source.

2.9.3 Necessary safety tools should be furnished fully when connecting and

cutting off electric.

2.9.4 All electric equipment should be connected to the ground in accordance

with current regulation of TCVN 4756:1989.

2.9.5 Setting up electric posts or placing electric equipment near areas of

collapsed possible earth and stone is prohibited.

2.9.6 Power source of area impacted by explosion should be cut off before

explosion, for soft cable leading to mobile equipment, equipment and cable

should be moved out of dangerous area to avoid stone casting. Electric line

should be checked after finishing explosion, if break-down not to be found,

resuming connecting electric.

2.9.7 Soft electric cable running across railway or road should be placed in

duct or suspended to avoid cable broken. Soft cable of equipment should be

put on the rack.

2.9.8 Cable joints and cable broken down must be sulfurized or placed inside

special connecting box.

2.9.9 Cable hook should be used while moving electric-operated mobile

machine, gloves and boots recommended.

2.9.10 Uninstalled electric line of trolley must be hung at least 2.5m high

from railway.



2.9.11 In case uninstalled electric line is carrying electric, prohibit:

- Climb up the post or locomotive for repair.

- Climb through cars.

2.9.12 Connecting uninstalled electric line of trolley tramcar for lights is

prohibited.

3. Safety requirement for stone processing.

3.1 Processing by machine.

3.1.1 Crushing and screening machine should be placed at the last position of

wind.

3.1.2 Every machine should be placed on separate platform with design

calculated stableness of the platform that is suitable to every machine. Anti-

dust part and sunscreen for equipment should be provided.

3.1.3 In case machine operating, prohibit:

- Use hands or foot for providing materials or take directly materials out from

funnel.

3.1.4 Materials with sizes suitable to regulation of the machine are only

provided when the machine attain stable revolving circle.

3.1.5 It's only allowed to stop machine when materials crushed up except for

case of sudden break down.

3.1.6 Operation process and safety regulations should be hung at working

place of machine.

3.1.7 Prohibit operation of crushing machine if:

- Defense coverings of transmission part are not provided or broken down.

- Bolts of the foot of machine and platform lost or broken down.

- Anti-dust measure is not provided.

3.2 Processing by hand.

3.2.1 Wearing gloves while breaking up rocks is prohibited. Broken stones

must be eliminated before breaking up.



3.2.3 Workers breaking up macadam have to sit in the horizontal row with a

distance of at least 2m.

3.2.4 After finishing breaking up, wasted earth and stone should be cleared.



Appendix 1

Regulation for procedure of asking for agreement in labor safety of

mining and processing enterprises

After location of pit mining has been allotted, leader of an enterprise is

required to send documents and materials to provincial, city, special zone

Service of Labor, Invalid and Social Affairs in order to ask for the agreement

in labor safety (two dossiers) included:

1- Decision of granting pit mining location by provincial, city, special zone

People's Committees.

2- Mine survey, geological documents approved already by competent

authority.

3- Map of mining and explosion areas of scale 1:5000, 1:10.000.

4- Plan for explosion and limit of dangerous areas.

5- Plan of design and mining.

6- List of explosion commanding officials, mine fire workers and mine

warehouse keepers.

After 30 days from receiving fully documents, Service of Labor, Invalid and

Social Affairs must give out official response text, otherwise, enterprise has

right to consider obtaining agreement in labor safety. After agreement made,

Service of Labor, Invalid and Social Affairs delivers back this enterprise a set

of documents, a set to be retained by it for supervision and inspection of

implementation.

Appendix 2



Regulation in building explosive warehouse of mining enterprise

1. Requirements of agreeing design explosive warehouse

1.1 When agreeing design of explosive warehouse, an enterprise should send

technical safety inspection organ and fire control organ of provincial, city

levels to ask for agreement of designing the following documents:

a) Agreement text of warehouse construction site of technical safety

inspection organ and fire control organ of provincial, city levels.

b) This design should indicate:

- Situation, characteristics of warehouse area.

- Basis to give out technical and economic facts.

- Measures of technical safety, fire control, anti-thunder system, power supply

and water supply.

c) Drawings of general level ground and section of works.

1.2 Technical design documents must be sent to agreement organs two sets

each with signature of design organ.

Design agreement organ is responsible for replying in writing within 20 days

from the date of receiving full design documents.

1.3 Design documents agreed in writing by Technical Safety Inspection Body

and Fire Control Body of provincial, city levels, with signature of the leader

of body, and a set of documents sent to design organ, a set retained for

supervising construction execution.

After agreement, Technical Safety Inspection Body and Fire Control Body of

provincial, city levels are responsible for reporting results to central Technical

Safety Inspection Body and Fire Control Department of Ministry of Police. A

copy of agreement documents should be sent to organ in charge of enterprise

at the same time.

1.4 After design documents agreed, side of construction design or side of use

wishing to make any change of design, have to obtain approval of agreement

organ before execution.



2. Technical safety requirements for explosive warehouse

2.1 Explosive warehouse must meet two requirements like anti-thief and

secured quality of explosive.

2.2 Explosive consuming warehouse must meet the following conditions:

a) Leakage proof, anti-termite and good ventilation. Ratio of area of window

on the floor: 1:25 to 1:30.

b) Ditch for drainage that has suitable inclination is provided.

c) Warehouses should be provided with ceiling. If roof made of reinforced

concrete, ceiling shall be unnecessary but insulator layer required. Roof of

warehouse should be made of non-flammable material.

d) Warehouse foundation and floor must secure dry all the time. The

foundation must be at least 20cm higher than surface of warehouse. The floor

must be at least 30cm higher than the foundation. The floor is able to be

paved with bricks, poured with concrete, or boarding. The floor must be even,

without any slit or hole.

®) Warehouses should be built two doors with locks. Flaps of doors must be

covered with tole and opened to the outside.

e) Warehouses should be furnished with ground system in accordance with

regulation of appendix 10 of Standard 4586:1988.

f) Warehouses should be equipped fully with fire control means. Quantity and

location for placing fire control means and tools shall be fixed by local Fire

Control Department.

2.3 In case an enterprise builds only a warehouse with different kinds of

explosive stored should abide by item 2.1.7 of TCVN 4586:1998.

2.4 Explosive warehouses used temporarily under 3 years, it is executed in

accordance with appendix 5 of TCVN 4586:1988.

2.5 All explosive warehouses must be checked before acceptance. Acceptance

council must be agreed by representatives of Technical Safety Inspection

Body and Fire Control Department for designing and building.



3. Set up warehouse records

3.1 An enterprise should set up warehouse records after finishing construction

of explosive consuming warehouse. A copy of the records must be delivered

to Technical Safety Inspection Body and Fire Control Department

respectively. Detail for setting up the records of explosive warehouse is

shown in appendix 6 of TCVN 4586:1988.

Appendix 3

Calculation of safety for explosion at open-pit mines

1. Safety distance for scattering pieces of stone by explosion.

Safety distance to guarantee person from scattering pieces of stone is defined

in accordance with design or passport of explosion.

At blank land, safety distance said above is not less than value given in Table

1.

Table 1

Form and method of mine explosion Smallest radius of dangerous area (m)

1 2

1. Small bore hole explosion with pocket No less than 200 (2)

2. Small bore hole explosion No less than 200 (2)

3. Small chamber explosion (pipe shaped) No less than 200 (2)

4. Large bore hole explosion As per design but no less than 200 (3)

5. Large bore hole explosion with pocket No less than 300

6. Pressed mine explosion No less than 300 (1)

Note:



1- Gross volume of pressed mines exploded at the same time (by delay cord

or electric primer) do not exceed 20 kg.

2- When explosion executed at the side of mountain, radius of dangerous area

to casting direction of stone is not less than 300m.

3- Radius of dangerous area indicated in Table is applied in case of large bore

holes covered.

When executing explosion of claymore mine and far casting explosion, radius

of dangerous area by earth and stone casted is calculated according to Table 2.

When executing explosion at the side of hill with a slope of more than 30 ,

radius of dangerous area by earth and stone casted increased 1.5 time to the

down side of slope.

When mine explosion of large bore holes (exploded impacted index n <4)

radius of dangerous area by earth and stone casted R is defined on the formula

(1).

2d

R = ------- ; m

W

In which:

d - Diameter of mine hole, mm;

W' - Smallest depth of mine hole - as shortest line calculated from the top

point of mine hole to free surface, defined on:

W' = C sin + l . cos , m

C - Distance from bore hole mouth to layer edge, m;

l = Length of hole knot , m;

- Incline corner of layer side against horizontal plane, degree.

Value of radius of dangerous area is calculated on the formula (1) shown in

Table 3.



Table 2

Impact index of exploded mine, n

1.0 1.5 2.0 2.5-3 1.0 1.5 2.0 2.5-3

Radius of dangerous area, m

For man for equipment, structures

1 2 3 4 5 6 7 8 9

1.5 200 300 350 400 100 150 250 300

Table 2 (end)

1 2 3 4 5 6 7 8 9



Table 3

Smallest depth

of mine W', m

Diameter of mine hole

Radius of dangerous area, m

Note: According to regulation of Table 1 of this standard, radius of dangerous area by

stone casting is not less than 200m.

2. Calculating safety distance due to impact of air wave rmin. Defining the

safety distance rmin by impact of air wave for man on requirement of work

accessing maximum to mine explosion location on the formula (2).

rmin = 15

In which:

Q as volume of explosive used, kg. If entrenchment or shelter provided, then

rmin can be reduced one-third. And for another cases, safety distance calculated

on formula (2) must increase double.

3. Calculating safety distance in shaking during explosion rc.

Safety distance in shaking for houses and structures by a concentrated

explosion calculated on formula (3).

rc = Kc.

In which:

rc - Safety distance, m;



Kc - Coefficient depending on nature of structure foundation necessary

protected, see in Table 4.

Q - Gross volume of explosive used, kg;

- Coefficient depending on index of impact for explosion n, see Table

5.

Table 4

Kind of foundation land of structure required

protection

Coefficient Kc

Origin stone

Exploded stone

Mixed gravel and macadam

Earth and sand

Clay

Embanked land and foundation land

Water saturated land (mud and coal land)



Table 5

Condition of explosion Coefficient

When underground explosion and when n:

n no more than 0.5

n =1

n=2

n no less than 3

Note: When explosion executed on the ground, it is not included impact of

seismism.

When a group of explosion of mine holes at the same time, if distance of a

mine hole to object required protection is not different more than 10%, safety

distance in shaking is able to be calculated on the formula (3), in which Q -

gross volume of explosive used.

If the distance from mine hole to object required protection is different more

than 10%, then see appendix 9 of TCVN 4586:1988 for safety distance in

shaking.

For safety distance, largest value should be chosen of three safety distances of

air wave, earth and stone casting level, shaking caused by explosion.


Documents

TCVN 5178-1990