Devco USA LLC U.S. Administrative Headquarters for the Bay Sulfur, California Sulphur, Devco Australia, Devco Overseas and Devco Services Companies 8801 S. Yale, Suite 250, Tulsa, OK 74137-3535 Phone (918) 496-4400, Fax (918) 496-4422

COMMENTS:

The hot plant started up with a control asphalt mix until the plant was up to operating temperatures. Once operations were stable, the plant was switched over to the manufacturing of the SEAM-Asphalt mix. SEAM was loaded into #2 Recycle Asphalt Pavement (RAP) hopper next to the #1 hopper containing micro-fine RAP. Both products were weighed and discharged on to a conveyor belt which transported and discharged on to a vibrating screen. Both products flowed through the screen and were conveyed to the RAP introduction collar on the drum where they were added to the heated aggregate.

The operator controlled the temperature of the mix between 280°F and 300°F with a few exceptions at the transition times when the switch was made to the SEAM mix and at the end of production. The temperature F dropped to ~250°F during the initial switch and the burner was adjusted accordingly to bring the temperature up to design parameters. At the end of the production of the mix, the temperatures reached as high as 325°F for a brief period.

The plant operated smoothly at a rate of ~350 tons per hour. The mix was transported to the paver with very few delays. Paving went smooth and was uninterrupted.

A TMX-412 monitor was calibrated to take spot readings of hydrogen sulfide (H2S). Readings were taken at the discharge of the drum feeding the bucket elevator, at the paving unit, and in the lab.

*The Oven was operating at ~810°F. The monitor was reading the H2S content on the outside and top of the oven which was at room temperature.

R. G. Bloom
Technical Manager
Devco USA LLC