N.M. Stat. § 31-6-1
The district judge may convene one or more grand juries at any time, without regard to court terms. A grand jury shall serve for a period of no longer than three months. The district judge shall summon and qualify as a panel for grand jury service such number of jurors as he deems necessary. Each grand jury shall be composed of twelve regular jurors and a sufficient number of alternates to insure the continuity of the inquiry and the taking of testimony. All deliberations shall be conducted by any twelve jurors, comprised of regular jurors or substituted alternates. No more than twelve jurors may deliberate. No juror may vote on an indictment unless the juror has heard all evidence presented on the charge. The district judge may discharge or excuse members of a grand jury and substitute alternate grand jurors as necessary. The names of jurors summoned for grand jury service shall be drawn from the master jury wheel of the district court for the county.
NMS § 31-6-1