1993-04-15_REVISION - M1977378 ‎(3)‎

• Permit No: M1977378
• IBM Index Class Name: REVISION
• Doc Date: 4/15/1993
• Doc Name: List of Concerns
• From: DMG
• To: Sunnyside Gold Corp
• Type & Sequence: TR14
• Media Type: D
• Archive: No

to all owners of record of surface rights to the affected land and
all owners of record of lands that are within 200 feet of the
boundary of the affected land, as well as the San Jaun County Board
of County Commissioners. The term "affected land" , as defined in
the Colorado Mined Land Reclamation Act, means the surface of an
area within the state were a mining operation is being or will be
conducted, which surface is disturbed as a result of such
operation. Sunnyside Gold will need to provide the Division proof
of notice prior to the decision date. Proof of notice may be by
submitting return receipts of a certified mailing or by proof of
personal service. The Division will further require that a copy of
all documents related to technical revision TR-14 be placed on
permanent file with the San Jaun County Clerk and Recorder and that
Sunnyside Gold provide an affidavit or receipt indicating the date
on which the documents were placed with the county clerk and
recorder. A permanent filing is deemed necessary in the case that
any activity that may take place in the area in the distant future
may require reference to the plans and designs for the bulkheads,
and a filing with the county clerk is seen as the best way to
ensure that the information will be available.
7. Removal of Underground Equipment, Facilities and Materials
Sunnyside Gold will be required to remove from the underground
workings, anything related to the mining operation which may serve
to contaminate the mine water pool once the workings are flooded.
Of particular concern would be any electrical transformers, sub-
stations, light fixtures that include ballasts and other items of
a similar nature. Other materials of concern would be fuel, oil,
grease and chemicals.
8. Potential for Failure from Thrust
The bulkhead design report submitted with this revision states:
The irregular blasted surface of the tunnels and the intimate
contact between the concrete bulkheads and the rock roof,
walls and floor of the tunnels permit a bulkhead to resist the
applied thrust. The only way a bulkhead can fail in shear is
by shearing through intact concrete or rock, not frictional
sliding. The poorly defined, but low, bond strength between
the rock and the concrete was conservatively ignored in the
calculations.
The report provides calculations related to shear failure within
the concrete, and provides data to show that the uniaxial
compressive strength of the rock is much greater than that of the
concrete, indicating that the strength of the concrete would
control. There is, however, little or no information included
regarding the shear strength of the rock as a mass, or the
resistance to shear of the rock-concrete interface.
The Division will require that:
(a) The degree of irregularity of the blasted surface of the
tunnels, after the scaling and washing operations, be
quantified and shown to be sufficient to prevent shear failure
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