Except as may be expressly authorized by these rules or by statute, no other forms of prehearing discovery shall be authorized or permitted including, but not limited to the following: interrogatories; requests for production of documents and things; requests for physical or mental examination; and requests for admission.
Ga. Comp. R. & Regs. R. 295-5-.05
O.C.G.A. 43-1-22.