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How far can the wind carry the dust generated in an aggregate exploitation?

October 16, 2018
Graph showing how far dust can be blown away by wind in an aggregate extraction site.

One of the reasons for controlling dust emission in farms is its great capacity to be moved by the wind, thus spreading its harmful effects on health and the environment outside the industrial facilities. Average dust particles (less than 10μm) can take up to one and a half hours to settle, during which time they are at the mercy of the wind. A gentle breeze of 14km/h can send these particles more than 40km from the quarry or mine, a distance that can increase exponentially as the particles get smaller. Fine particles of less than 1.5 μm behave like aerosols, remaining indefinitely in suspension.

SizeSedimentation rateSedimentatrion time since 15m
1000 μm395 cm/s4 s
100 μm29.6 cm/s51 s
10 μm0.296 cm/s1h 25s
1 μm0.0035 cm/s5 days
0.1 μm0.000035 cm/s496 days s
SizeLaminar wind 10 km/hLaminar wind 30 km/h
1000 μm11 m33 m
100 μm150 m430 m
10 μm14 km42 km
1 μm1200 km3600 km
0.1 μm3 laps of the earth9 laps of the earth

As can be deduced from the graphs, the dust produced in an aggregate operation does not only affect the operation itself, but also goes beyond its limits and where it settles it can reduce the quality of crops such as vines and fruit trees, slowing down the growth of other plants. The dust in suspension can reduce visibility on nearby roads and paths and affect nearby populations with respiratory discomfort.

Among the preventive measures there are 3 main ones, the control of dust sedimentation by humidity, the elimination by aspiration and subsequent separation and the simplest and most economical, the fairing or hooding of the emission points.

Capotex has been offering hooding solutions for all types of conveyor belts for over 20 years. Hooding is a highly efficient passive treatment that will not consume resources or energy. Their installation cost is low, especially compared to other systems, as is their maintenance. A bonnet confines dust from spreading, protects workers from the risk of entrapment or accidents due to falling materials and helps to preserve belts and motors, while preventing product loss.