Monthly Archives: February 2011

Schedule MicroScan Image Post –

Carban Particulate

MicroScan Image Dust Particles

Dust Particles

This is a piece of organic material under bacterial attack by Microphage, (little dark lumpy filaments) and mildew (long clear filaments)

Single Bucket Unit Picture

Wet Weather in all areas of South Africa, Except the Western Cape

Wet Weather in all areas of South Africa, Except the Western Cape is impacting the fallout dust levels in the country.

Supply of Dust Monitoring Equipment to Africa and Internationally

Supply of Dust Monitoring Equipment to Africa and Internationally

9 Fallout Dust Monitoring Reports Completed Last week

9 Clients worked on last week

The effect of heavy & sustained rains on fallout dust monitoring.

The effect of heavy & sustained rains on fallout dust monitoring.


During weather of this type we note:
– General dust levels of agricultural, topsoils or other environmental dusts are lower due to the sources being saturated rather than the water droplets milking out the airborne dust.
– Production dust, however, is not greatly affected as any crushing, blasting or milling operation will still generate dust.
– Because of the above 2 factors the content of fallout dust will now have higher production dust as a percentage content but less in terms of the total dust concentration (the agricultural soil dust is almost non-existent).
– Organic debris will be lower as well.
– Pulverised roadway generated dusts will be lower or almost absent except where heavy traffic dried the surface.
– The sustained rainy & wet conditions have been extensively studied in the Western Cape area which has such rains during winter periods.
– Results can be in the order of 5-10% of the normal dry weather dust conditions.
– The recovery of dust levels will take some time as roads & dusty areas will need to dry out before the dust levels start to increase again.
– During the “recovery” period the first thing that increased is the organic debris & insect debris.
– During extended heavy rain periods the addition of algaecides needs to be increased as the acidic rain addition will encourage the development of algae & other bacterial colony growth. Fortunately these do not add a lot of mass to each sample, but as a percentage this organic material increases a lot as the overall mass remains low.
– Due to the increased humidity of the air production dust will not travel as far as the air density is lower & cannot thus support dust with the result that the precipitation rate gradient is steeper ie. Production dust from a crusher installation will perhaps all precipitate out within 80-100metres (no wind) while in dry weather the material fines could still be in suspension at half a kilometre.
– The d0.50 average particle size of production dust at a given DustWatch position will be finer.
– Remember acid + base = salt & therefore the salinity of the water will increased. This fortunately does not add mass to the sample.

New mining equipment to boost fight against silicosis

‘XRD’ is the new buzz word in the CSIR mining research group’s corridors.

This new piece of equipment, also known as theBruker D8 Advance, is an advanced X-ray diffractometer that promises to speed up and improve the quality of the CSIR’s laboratory analysis of silica dust.

“Respirable silica is a serious health concern in the gold mining industry,” says researcher Cecilia Pretorius. “Exposure to silica dust causes silicosis, a deadly lung disease, which is a major concern for the South African mining industry.” The XRD can analyse the phases or crystal forms of a material to determine the substances that are present in a specific sample. In mining it is used to determine what proportion of a dust sample consists of quartz. “It is the quartz component of the silica dust that is the culprit,” says Pretorius. Read more »

What Is Dust And How Is It Defined?

As dust is fine solids or, in some cases liquids, there needs to be a system of measuring the particulate size and then to categorise the various dusts by size to see to what extent the dust is ingested.

The particulate can be measured by various means but within the metric system of measurements, we use the term micrometer or micron, which is an exceedingly small measurement of one-one thousandth of the millimetre.  The human eye will only see a profusion of dust in the air under certain conditions – predominantly if one is viewing the plume of dust against a blue sky against the light.  This presumes of course, that the dust concerned has a low reflective index and the colour has the greatest contrast with the sky colour as possible.

A lime dust plume is far more visible than cement, which is grey – less of a contrast against the sky’s blue.  Similarly, coal dust will be visible against the sky, whereas a light grey roadway dust will be less visible.

Full Article Here

Dust Is Not Dust. Or Is It?

The information here on dust covers basic information and knowledge that all Environmental Practitioners, Occupational Hygienists, Ventilation Engineers and health professionals, as well as health safety professionals should not only have a working knowledge of, but should be able to apply.  While omitted from the above list, the Architect or Architectural Technologist should equally be aware of and apply the above principles, as the confining of an atmosphere containing dusts will increase the health risk associated with persons moving, living or working in the area or “space” – residential, office or hospital.

Dust by definition can constitute any particulate or matter fine enough to become airborne and will include rock, solid materials, organic substances, vapours, fumes, mists, fogs, smokes and under the correct conditions, fine gravels, flaky material, fibres, moulds, bacteria, microbes or small and sub-micronic insects.

Full Article Here