Yes - There is a method called the drop box test. A fixed quantity of representative material is dropped into an enclosed box and a sample of the air is aspirated from the box to determine the amount of dust in the air. The aspirated sample can also be analyzed for sizing. This should be performed several times if the material varies significantly in size. The test should also be repeated over time if the material is prone to weathering such as coal.

Chris Blazek

Benetech Inc.

blazekc@benetechusa.com ■

Dear Sir,

I know of the Heubach Test which is a reference.

I feel bad since I cannot give you the address but I know that it is manufactured by Dr. Heubach in Germany.

I hope this is sufficient to get the address of Dr. Heubach.

Dr. Wolbier ought to help you.

Now there are other tests and one of them is to measure the light extinction of a population of solid particulates during their settling or equivalently the cloud dedusting.

I dare not to say that there is standard test since as we know there some many variables which are not easily reproducible during dusting.

Kind Regards,

Pierre ■