Previous Page  31 / 44 Next Page
Information
Show Menu
Previous Page 31 / 44 Next Page
Page Background

December 2015

MODERN MINING

29

MATERIALS HANDLING

fea

ture

T

his is the view of Michael van

Niekerk from ASP Fire, who goes

on to add: “Conveyor belt sys-

tems and supporting structures

are normally of non-combustible

construction; however, any large fire may

damage or cause the collapse of the structural

elements. The principal fire load includes the

material being conveyed, the mechanical com-

ponents of the system, and the belt itself.”

He says there is a misconception that con-

veyors are not easily ignitable, which can often

prevent mines from taking the necessary pre-

cautions to ensure that there is sufficient fire

protection in place: “Once a conveyor fire

starts, it will grow rapidly and become very dif-

ficult to control in a very short period of time.”

He points out that belts contain polymeric

materials, which present a serious risk in terms

of rapid fire spread and the generation of toxic,

corrosive smoke – making these fires lethal and

incredibly difficult to control.

In June 2015, for example, a fire that burned

a multi-story conveyor belt at a Lake Elsinore

aggregate mining and crushing business in the

USA caused an estimated US$13 million in

Fire protection essential

for conveyor belt systems

Belt conveyor systems are used exten-

sively in the mining industry – they

provide an ideal solution to transport

manageable sized material from one

processing point to another. Using

such a system reduces the reliance

on manpower and reliability is maxi-

mised. However, a key protection area

that has to be considered is how to

best handle the issue of conveyor belt

system fires.

An underground conveyor

tail pulley fire with water

mist system in action.The

water mist fire suppression

systems available from ASP

Fire force water through

micro nozzles at a very high

pressure to create a water

vapour mist. Fire extin-

guishing occurs due to a

combination of the cooling

effect of the water mist and

the displacement of oxygen

caused by the expansion

of the water mist as it is

vaporised.

damage and took firefighters more than two

hours to contain. “When you consider the

overall loss caused by a conveyor belt fire,

you can’t just think about the possible loss of

lives, injured staff and the loss of expensive

equipment, but you also have to consider the

excessive loss of revenue that will be incurred

by the downtime required to fix or rebuild the

conveyor belt,” says van Niekerk.

“As such, the essential ethos behind any

quality conveyor belt fire protection needs to

revolve around the preservation of the con-

veyor belt system itself. Hence, the need for

early detection and the quick and successful

extinguishing of any fire, while simultaneously

cooling the affected structure, remains key.

“It is important to note that every conveyor

belt system is unique and, as such, an individ-

ual assessment has to be made for each system

in order to adequately and accurately deter-

mine where the fire risks lie for that particular

system design.”

He notes that – in his experience – the

most common causes of conveyor belt fires are

static heat build-up from friction caused by

belt movement, moving fire on the belt itself,