(a) Term. A grand jury shall serve until discharged by the Assignment Judge, but not longer than 20 weeks unless the Assignment Judge shall order it continued as hereinafter provided. A grand jury shall not be discharged before the expiration of its term of service except for good cause. The continuance of such grand jury shall not affect the usual drawing, selecting and serving of further grand juries.
(b) Order for Continuance. Whenever it appears to the Assignment Judge that the grand jury has not completed its labors, although its ordinary term is about to expire, the Assignment Judge may, if satisfied of the necessity therefor, order that its term be continued. The order shall be made and filed within the session of court for which such grand jury shall have been drawn, and shall provide a continuance for a definite period of time not exceeding 3 calendar months, provided, however, that the Assignment Judge may make a further order, or orders, continuing such grand jury in office for a further term or terms of 3 calendar months each.
