2015-02-02_PERMIT FILE - P2014022

• Permit No: P2014022
• IBM Index Class Name: PERMIT FILE
• Doc Date: 2/2/2015
• Doc Name: Responses
• From: Norwest Corporation
• To: DRMS
• Email Name: THM
• Media Type: D
• Archive: No

NORWEST
C O R P O R A T I O N
Page 3
January 30, 2015
Letter to Mr. Marshall
abandoning of these holes by way of controlled placement of
bentonite chips from the bottom of the hole to 10 feet below
ground level, and placing a Portland cement cap from the top of
the bentonite to the surface. The one deep hole (GRH -1), being the
most likely drill hole to encounter groundwater in substantial
quantities, will be cemented from hole total depth to the surface.
2. Please sped the anticipated time frame from start of well
drilling to well plugging and abandonment. What methods will
be employed to ensure aquifer isolation during drilling and
well plugging and abandonment?
Barring any unforeseen circumstances, the drilling program is
anticipated to take between four (4) and six (6) weeks to complete
from commencement of drilling operations to the completion of
plug and abandonment operations. Dirt work is anticipated to
commence immediately upon approval from DRMS, with drilling
operations commencing a few days thereafter.
Within the Green River Formation in the Uinta Basin, there are
three (3) known aquifers. These include local alluvial aquifers, the
Bird's Nest Aquifer, and the Douglas Creek Aquifer. Unlike the
Piceance Creek Basin, which contains a number of individual
aquifers, including the A- Groove and B- Groove Aquifers which
bound the Mahogany Zone, the Uinta Basin only contains Alluvial,
Bird's Nest, and Douglas Creek Aquifers.
Alluvial aquifers are small, localized aquifers only found in the
unconsolidated sediment associated with drainages within the
basin. Because the drill hole locations are located on the tops of
ridges away from the drainages and contain little unconsolidated
sediment, alluvial aquifers are not expected to be encountered.
The Bird's Nest Aquifer is a zone approximately 115 -140 feet
thick within the upper units of the Parachute Creek Member of the
Green River Formation in the Uinta Basin that contains abundant
dissolution features (vugs, voids, small cavities) and is often water -
bearing. The base of the Bird's Nest Aquifer occurs approximately
250 feet above the top of the Mahogany Zone. For the proposed
drill holes, the uppermost Green River Formation has been eroded
away (to within 50 feet of the top of the Mahogany Zone). Thus,
the Bird's Nest Aquifer does not exist in the project area.