STOCKTON, Calif. (April 19)—Huffco Manufacturing Co. is expanding its manufacturing facility and boosting capacity to further diversify its product line. The rubber mats manufacturer will spend about $518,000 to increase capacity, primarily to make rubber ties and sports flooring used beneath and around exercise equipment and playground equipment. Of that figure, approximately $250,000 is covered by a grant awarded by the California Waste Management Board. The firm hopes to complete the production expansion in the next two months. Huffco also is adding 5,000 square feet to its 60,000-sq.-ft. factory for an undisclosed amount.