Nev. Admin. Code § 534.4357 - Monitoring wells: Placement of gravel and seals in annular space
1. If the water or vapors which are being
monitored in a monitoring well are not encountered within 5 feet below the
surface of the ground, the well driller shall place in the annular space of the
well:
(a) From the bottom of the well to a
maximum of 2 feet above the uppermost perforation in the casing, a gravel pack
which consists of quartz sand, silica or other materials which will not
contaminate the groundwater or the geologic formation;
(b) From the gravel pack placed pursuant to
paragraph (a) to a minimum of 2 feet above that gravel pack or to within 20
feet below the surface of the ground, a seal consisting of bentonite chips;
and
(c) From the seal placed
pursuant to paragraph (b) to the surface, a seal, with a minimum thickness of
20 feet below the surface, consisting of cement grout, neat cement or concrete
grout.
2. If the water or
vapors which are being monitored in a monitoring well are encountered within 5
feet below the surface of the ground, the well driller shall comply with the
requirements of subsection 1, except that:
(a)
The gravel pack required pursuant to paragraph (a) of subsection 1 must extend
only 6 inches above the uppermost perforation in the casing; and
(b) The surface seal required pursuant to
paragraph (c) of subsection 1 must be placed from 1 foot below the surface to
the surface.
3. The well
driller shall ensure that a bridge does not occur in the annular space during
the placement of the gravel pack and seals required pursuant to this
section.
4. If more than 20
continuous feet of grout are placed in the annular space of the well or if
there is standing liquid in the borehole above the sealing depth, the grout
must be placed by tremie pipe in an upward direction.
Notes
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