INSPEC03872

• Permit No: M1977342
• IBM Index Class Name: Inspection
• Doc Date: 10/6/1993
• Doc Name: MINERALS PROGRAM INSPECTION REPORT
• Inspection Date: 10/6/1993
• Media Type: D
• Archive: No

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(Page 3)
MINE ID f OR PROSPECTING ID ~ K-77-342
INSPECTION DATE 10-6-93 INSPECTOR'S INITIALS ACS
inspection.
The groundwater monitoring well location established in meetings between the Division and the
operator during August of 1993 was inspected. The well ie located in glacial materials just
downhill (east) of the mine yards. Well completion was ongoing at the time of the
inspection. The operator should eubroit well completion and development details as they are
available.
The glory hole that has developed on Red Mountain ae a result of the panel cave mining method
employed at Henderson is not included within the permitted affected land;a outlined in the
MLRB Permit. The glory hole was not visited during this inspection, but will be made a
priority at the next inspection if accessible. Affected land ie defined in the Mined Land
Reclamation Act ae "the surface of an area within the state where a mining operation ie being
or will be conducted, which surface is disturbed as a result of such operat:on". It is clear
that the glory hole area fits the definition of affected land, and should t~e included in the
permit. Inclusion of the glory hole will require a permit amendment. The operator should
contact the Division to set up a pre-amendment meeting and a submittal time-table, as it is
believed that discussions as to the form the amendment should take will streamline the
process for both parties.
Mill Site !Grand Countvl
Division inspectors received an overview of the mill site which focussed on well installation
that has been initiated for the mill Bite to comply with Rule 6.2(3). Holeei had been drilled
in keeping with the guidelines discussed during a July 1993 meeting between the Division and
the operator. Logging of the holes waa used to identify the elevation of the contact with
pre-Cambrian basement, particularly on the north aide of the tailing impoundment. Holes that
intercepted the contact below the ultimate tailing elevation were comple~:ed ae monitoring
wells. The operator also completed monitoring well(s) in the formations above basement
between the tailing dam and the williame Fork River. The operator should submit details of
the groundwater characterization program, including well completion and development
information, ae the details become available.
The crushing, milling, packaging and shipping facilities were not inspected on this trip, nor
was the rail portal or rail line. It was noted that the mill site entrance sign had been
posted in accordance with Rule 6.7.
The tailing impoundment was inspected. Water contributions from above the impoundment are
intercepted and routed through a canal around the impoundment back to the Ut.e Creek drainage.
Seep water from the tailing under-drains ie collected and pumped back to th<~ free water pond.
This same pumping station ie used to send water decanted from the tailing pond back to the
mill process water pond (East Branch Reservoir). If the pump back system were to fail, the
seep water collection area would overtop in a few hours; in order to prevent such an
occurrence, the operator has installed an alarm system that would alert mill personnel
(continuously present) that the pump-back was not operating.
The operator appears to be stripping and stockpiling topsoil from the tailing disposal area
in accordance with the technical revision approved by the Division in March of 1991, although
no detailed measurements or observations of the stockpiles were made. Topsoil is currently
being stripped in advance of the westward progression of the tailings as the disposal area
fills, and ie being stockpiled below the interceptor canal at the west end of the
impoundment.
Approximately 100 million tone of tailing have been disposed of in the impoundment at the
present time, the dam ie approximately 160 feet in height. The dam i.s constructed of
hydraulically placed tailing sands. Piezometera have been installed in the tailing pile. The
operator maintains a 1000 foot set-back from the tailing dam to the free water pond. With
a 1 percent elope of the tailing surface, this set-back provides ten feet of: free-board. The
1000 foot set-back line ie marked with stakes in the tailing. Carl Wood, mill site
engineering manager, stated that stability analysis for the dam and tailing pile had recently