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     Office of Air Quality, Permitting & Enforcement Division

               Mechanical Section Policy Memorandum


Date:  February 23, 1994                            No.: 11

From:  Skip Clark, P.E. 

Approved by:  Gary Wallin, P.E. 

Subject:  Standard Exemption No. 73



The production rate of 200 tons per hour for a rock crusher
under Standard Exemption No. 73 means the total production or
output from the entire facility.  


If a facility screens the material before it goes to the
primary crusher in order to bypass a portion of the feed, the
total production should include both the primary crusher
material and the bypassed material.  The company may want to
bypass the fines, or small material, from the primary crusher
in order to maximize the output of the crusher and not waste
crushing capacity on material that is already sized.  The
intent of this exemption was to limit total production to 200
tons per hour.  

Also, the rated capacity of the crusher is the determining
factor on its size.  A crusher with a rated capacity greater
than 200 tons per hour is not allowed even if the company
welds, or attaches, some type of devices on the feed end to
limit the input to the crusher.  

Also, if the facility has a secondary, or tertiary, crusher to
process the output from the primary crusher, they are allowed
since the total production from the facility will not be
greater than 200 tons per hour.  

Necessary Action:  

Clarify the wording in the first sentence of this exemption to
reflect the original intent of this exemption.  

cc:  All Mechanical Section