The proceeds from the sale of any bonds issued under authority of this article shall be applied only for the purpose for which the bonds were issued; provided, however, that any premium and accrued interest received in any such sale shall be applied to the payment of the principal of or the interest on the bonds sold; and provided, further, that if for any reason any portion of the proceeds shall not be needed for the purpose for which the bonds were issued, such unneeded portion of the proceeds shall be applied to the payment of the principal of or interest on the bonds.
S.C. Code § 44-7-1550