Judge B M Angadi extended the custody after they were produced before the court through video conferencing from Parappana Agrahara jail where they are lodged.
Reddy's wife Aruna Lakshmi, who is on bail, was present in the court.
Meanwhile, Reddy's personal aide Mehfuz Ali Khan, who is also an accused in the case, filed an application seeking bail for a second time, along with a copy of the High Court order dated July 24.
Counsel for Mehfuz Ali Khan said Ramzan was fast approaching and his client has a five-month-old child. As per religious tenets, a child has to spend his first Ramzan along with his parents and therefore his client be granted bail, he submitted.
The court then posted his bail application to August 8 for the CBI to file its objections.
On July 24, the CBI Court had rejected bail applications of Deputy Conservator of Forest A C Muthaiah and S P Raju, accused in the case, on the ground that there was "sufficient material to show their active involvement in the illegal mining of AMC".
Reddy was arrested along with Khan in September 2011 by CBI.