Ssangyong Cement Industrial Co., South Korea’s largest cement manufacturer, said Friday that it plans to sell US$200m in floating rate notes.   The three-year secured debt will carry a coupon rate of six-month London Interbank Offered Rate (LIBOR) plus 0.2 percentage point.  The proceeds from the debt sale will be used to refinance and pay off maturing debts, it said.  The deal will be arranged by the Korea Development Bank, one of South Korea’s state-run lenders.