W. Va. Code § 52-2-3

The clerk of any circuit court requiring a grand jury shall, at least thirty days before the term of court, draw and assign persons for the grand jury, but the court, or judge thereof, may require the clerk at any specified time to draw and assign grand jurors for either a regular, special or adjourned term of court. When required by the circuit court or the chief judge thereof, the clerk shall draw the names of sixteen persons from the jury wheel or jury box, and the persons so drawn shall constitute the grand jury. At the same time, the clerk shall draw the names of such additional numbers of persons from the jury wheel or jury box as the chief judge of the circuit, or the judge in a single judge circuit shall by prior order direct, and the persons so drawn shall constitute alternate jurors for the grand jury. The judge may replace any absent members of the grand jury from among the alternate grand jurors, in the order in which the alternate jurors were drawn. The clerk shall enter the names of all persons so drawn in a book kept for that purpose and shall issue summonses to the persons so drawn in the same manner as that provided for petit jurors in subsection (b), section seven, article one of this chapter.