By John S. McClenahen Senior executives of 14 U.S. companies are slated to accompany U.S. Secretary of Commerce Donald L. Evans on a business development mission to Mexico City and Monterrey June 17-20. The trip's purpose is to explore and expand U.S. export opportunities in information technology, telecommunications, environmental control, medicine and manufacturing. Mexico is the second-largest U.S. export market, after Canada. U.S. exports to Mexico totaled $102 billion in 2001. The companies scheduled to go are Advanced Environmental Systems Inc., Balboa Energy Technologies Inc., Borland Software Corp., Damon S. Williams Associates LLC, Eli Lilly & Co., EnviroSystems Inc., International Mobile Communications Inc., Kansas City Southern, Mechanical Solutions Inc., PanAmSat Corp., Protec Inc., Reade Advanced Materials, Transit Sales International and Walbridge Aldinger Co.