( Nasdaq : ZINC ) , the parent company of Horsehead Corporation and a leading U.S. zinc producer and recycler of hazardous waste , today announced the successful completion of its previously announced underwritten public offering of 8,050,000 shares of common stock at $ 10.50 per share , including 1,050,000 shares sold pursuant to the underwriters ' exercise of their over-allotment option to purchase additional shares .