1997-05-20_REVISION - M1977378

• Permit No: M1977378
• IBM Index Class Name: Revision
• Doc Date: 5/20/1997
• Doc Name: Bulkhead Design Submittal
• From: Sunnyside Gold Corp
• To: DMG
• Type & Sequence: TR14
• Media Type: D
• Archive: No

JOHN F. ABEL,JR.
MINING ENGINEER
310 LOOKOUT VIEW COURT
GOLDEN,CO 80401
303-279-4901
FAX [phone]
May 7, 1997
Mr. Larry Perino
Sunnyside Gold Corp.
P.O. Box 177
Silverton, CO 81433
Dear Larry:
As you requested I have prepared the design for a bulkhead for
the maximum possible head at the Ransom Tunnel . The bulkhead
design calculations follow this letter report . The approximately
10-foot wide by 10-foot high bulkhead is designed to resist 635
feet of hydraulic head (275 psi hydraulic pressure) . The
portal-side face bulkhead location is 319 feet from the portal and
bulkhead is 8 feet thick, i .e. it will extend from 319 feet to 327
feet in from the portal when constructed. It was necessary to
locate the bulkhead under 114 feet of overlying latite porphyry in
order to eliminate the possibility of hydrofracturing the formation
if subjected to the maximum 275 psi hydraulic pressure. The latite
porphyry exposed in the Ransom Tunnel is the same strong competent
semi-massive rock type found where the American Tunnel bulkhead was
installed. The bulkhead is designed to include #10 bars in a
two-way mat. 3 . 5 inches in from the portal-side face of the
bulkhead. The bulkhead is designed to contain temperature and
shrinkage reinforcement at approximately 3 inches inside the form
for the waterside bulkhead face, either a two-way mat of #4 bars on
12-inch centers, or a two-way mat of #6 bars on 18-inch centers, or
a combination of these bar sizes at their specified spacings in a
two-way rebar mat. The Ransom Tunnel bulkhead will require a
cofferdam, bypass pipe and valve for the water currently exiting
the portal, the same as was the case for the American Tunnel and
the Terry Tunnel .
Three potential bulkhead locations were inspected on May 5,
1997, at 293 feet, 319 feet and 446 feet from the portal . These
locations are in the most favorable rock sections between the
Ransom Tunnel portal and the partially open fracture approximately
670 feet from the portal . The width of the openings visible from
the Ransom Tunnel along this nearly vertical fracture are as much
as 2 feet wide. The openings are principally on the east side of
the tunnel . This partially open fracture was dry when inspected.
It was indicated as a water course on the mine map. Apparently,
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