Depositions may be used at trial, but there are many requirements that must be satisfied first. Look to S.C. Civil Procedure Rule 32 for the requirements.
Depositions may be used for impeachment purposes in most situations. This would most likely fall under SCRE 613 (prior inconsistent statement). Click here for a post on the steps necessary for complying with 613.
Depositions may also be used at trial as substantive evidence if several conditions are met:
Lynne C. Hermle and Michael Delikat have written a great piece for the American Bar Association that breaks down the use of depositions at trial and the many requirements before introduction: Use of Deposition Testimony at Trial