2016-07-28_REVISION - M1980244 ‎(2)‎

• Permit No: M1980244
• IBM Index Class Name: Revision
• Doc Date: 7/28/2016
• Doc Name: Adequacy Review Response
• From: Newmont
• To: DRMS
• Email Name: TC1
• Media Type: D
• Archive: No

VOLUME II OF IV
HYDROGEOCHEMISTRY EVALUATION/DECEMBER 15,2015/ADRIAN BROWN
3.4.1 Ground Water Flow
• Page 7: The first sentence mentions "three principal historic drainage tunnels"and
refers to Plate 4—Diatreme. However, Plate 4 only shows the Carlton Tunnel. If
the other two drainage tunnels were meant to be shown on Plate 4(as
indicated), please revise Plate 4 to show all three tunnels.
RESPONSE. A revised Plate 4 is included in Attachment 1. The two other
drainage tunnels, the Moffat Tunnel and the Roosevelt Tunnel are described in
Section 3.4.1, items 1 and 2. Flows from both of these tunnels essentially ceased
when the Carlton Tunnel became operational. The groundwater model is not
influenced by either the Moffat or the Roosevelt Tunnel, so they were not depicted
on Plate 4. A revised Plate 4 is provided in Attachment I with the Moffat and
Roosevelt Tunnels for reference purposes only. In adding these tunnels, additional
research indicates that the description of the tunnels in the report is partially
incorrect, conflating the Moffatt Tunnel with the El Paso Tunnel, and is
incomplete, omitting the Standard Tunnel. The initial portion of the text in Section
3.4.1 should read as follows and the revised Plate 4 should be substituted, showing
the locations of the relevant tunnels.
Revised Text for Hydrogeochemistry Evaluation Report:
3.4.1 Ground Water Flow
Ground water flow in the District has been collected and removed from the Diatreme
since 1903 by a number of principal historic drainage tunnels (Plate 4—Diatreme):
1. Moffat Tunnel. The Moffat Tunnel(also known as the Ophelia Tunnel) enters the
granite at the west base of Gold Hill at an elevation of 9,268 feet. In December, 1896,
this tunnel was 2,600 feet in length, with a discharge estimated at from 2,000 to 2,100
gallons a minute. The tunnel maintained this flow for over a year, becoming dry in 1898
(Lindgren and Ransome, 1906)
2. Standard Tunnel. The Standard tunnel, begun in January, 1896, has its portal in the
granite west of Beacon Hill, at an elevation of 9,027 feet. Its objective was the phonolite
plug of Beacon Hill[southwest of the main diatreme]. In February, 1896, the tunnel cut
the El Paso vein, whence issued a flow of 250 gallons a minute. The water became more
abundant as the contact between the granite and phonolite was approached, and in
1898, when the phonolite was reached, the flow amounted to 1,000 gallons a minute.
This rapidly increased as the tunnel penetrated the phonolite and in 1899 the maximum
flow of from 12,000 to 18,000 gallons a minute was attained. Work was finally
abandoned in June, 1899, when the tunnel had been driven 2,800 feet. By the end of
1901 the tunnel was dry(Lindgren and Ransome, 1906).
3. El Paso Tunnel. The El Paso Tunnel was driven in 1903 from a portal elevation of
8,783 feet from the south of the city of Cripple Creek to the north-east, and is
approximately one mile long. Flow from the tunnel was initially as much as 7,000 gpm,
reducing to less than 2,000 gpm by 1906 Flow from the tunnel ceased when tunnels at
lower elevations reduced the water level in the Diatreme below the elevation of the
tunnel.As was the case with the Standard tunnel, the El Paso slowly lowered the
water in the Mary McKinney and Elkton mines, showing that there is a connection
through open fissures between the Beacon Hill phonolite and the main volcanic neck
(Lindgren and Ransome, 1906).
4. Roosevelt Tunnel. [no change]
5. Carlton Tunnel. [no change]
Page 2 of 28