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CO~RSE ~66REG~TE

    Coarse aggregate with a uniform gradation around 4~' serves as

both a good bearing surface and a dust palli~tive    When placed

in a 12'  thick lift this coarse aggregate functions well as a

helipad.   The grain size should be no less than 2" to avoid FOD

problems

~eoetation and Deflation ~rmor    Yegetation acts as natural dust

control.   Similarly the rocky crust or deflation armor, found in

the desert.  is an effective dust palliative unless it is

disturbed.   By controlling vehicular- traffic we can preserve the

deflation armor and reduce the scope of our dust ~roblem.

Resins   Petroleum based or naturally occurring resins (eg lignin)

work similarly to bituminous products    Resins are applied as

penetrants or admixtures and perform comparably with bituminous

products.   Organic resins such as lignin base are environmentally

safe and do not discolor the soil as much as bitumen.   These

characteristics might justify their use in special  instances

despite higher cost (approx. t4.~~ per square meter).

Brine Solutions   Solutions of salts including CaClq MgClq and

NaCl suppress dust through two mechanisms.   They pull moisture

from the air (deliquesce) and cause dust particles to stick

together    This will only occur if the relative humidity is over

3~%.   When sprayed on a surface  brine solutions also tend to

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