September 2, 2005

Alan Vaught
Mauro Sandoval
Thompson Scale Co.
2758 Bingle Road
Houston, TX 77055

Alan and Mauro,

I am writing to thank you for the help you provided during the replacement of our Bemiscan packer controller with Thompson Scale’s 4693 Controller. Thompson Scale provided expert assistance in technical support for the physical installation, wiring, and setup of the 4693 Controller. Thompson was also receptive to our request for a software modification of the 4693 bag filling operation to have a manual discharge on product flow errors.

A long-standing previous goal with the Bemiscan system was to maintain a rejection rate of < 2%. This was typically attainable for only a few days or weeks. The latest software E-PROM was installed during the 3rd week of July. Since then, our checkweigher-based rejection rate has been < 0.2%. This is phenomenal for us!

This software made a huge difference from the previous software. I don’t know if it is attributable to the fact that we don’t automatically discharge bags when a flow problem occurs or if, maybe, the previous chip had a glitch. Occasionally, I used to see an extreme overweight bag followed by an extreme underweight bag. With the latest chip, this is no longer the case.

Again, I want to thank Thompson Scale for the improvements we have seen since changing out our control system to the 4693 Controller. The expertise and service that you and your staff have is commendable.

Sincerely,

Darrell Stodola
Koppers Inc.