INSPEC21802

• Permit No: M1980244
• IBM Index Class Name: Inspection
• Doc Name: DMG MINERALS PROGRAM INSPECTION REPORT
• Inspection Date: 10/3/1994
• Media Type: D
• Archive: No

(Page 2)
MINE ID # OR PROSPECTING ID # M-80-244
INSPECTION DATE 10-3-94 INSPECTOR'S INITIALS CBM
OBSERVATIONS
This was a regular monitoring inspection which concentrated on the soil liner and geomembrane
liner installation on the heap leach pad. Also inspected were the sump above the toe berm
and the water discharge point below the Carlton tailings in Arequa Gulch.
The Ironclad spent ore detoxification, sorting and stockpiling area was inspected first.
This is the area in which the Ironclad spent ore is run through a three inch screening plant,
screened material then has calcium hypochlorite added to it and the mixture is stockpiled for
later transport and laid down ae the soil liner for the heap leach pad. The calcium
hypochlorite addition rate to the soil liner material is checked each morning and the flow
rate ie adjusted accordingly. This morning it was determined that calcium hypochlorite was
being added at the rate of approximately 3.2 pounds per ton of liner material. It waa also
determined that the raw spent ore is being contained upon the spent ore liner ae required.
The leach pad liner construction was inspected next. since the geomembrane liner had
"luffed" in the strong winds on Saturday evening, the liner may have experienced undue strain
in several areas. Some suspect areas are noted here. The eastern edge of the liner near the
top anchor trench showed a small (1 to 2 foot) tear around a weld. The liner to either aide
of this tear showed evidence of strain. The outline of the edge of the anchor trench was
well defined because the liner appeared to have been pulled tight against the trench edge.
This section of liner may need testing and replacement. There were several folds in the
liner which were pulled out by work crews from 1030 hours to 1215 hours. Areas where the
liner had folded did not appear to be greatly affected by the folding and creasing but were
being carefully inspected by the construction Quality Assurance (CQA) team.
Areas below the folding in the liner or approximately 150 feet down from the top anchor
trench on the south aide were partially walked with two of the Golder CQA team members. It
was noted that, in at least three areas, pieces of scrap material that were left under the
liner had bunched up and are now preventing the liner from coming into solid contact with the
soil liner surface. These three areas were just west of the western moat cut used to
reposition the liner, at the bottom of weld 68-69 and just south of the eastern most cut used
to reposition the liner. These pieces of scrap material must be removed and the liner
repaired. Ae a general practice, DMG does not believe that it ie a good idea to leave any
scrap materials underneath the liner since these could become folded with thermal expansion
and contraction of the liner. It was also noted that several small rocks in the area below
the main fold have rotated out of the soil liner and now need to be removed. Areas above the
fold were also inspected and no problems were noted. The entire liner that ie now installed
must be reinspected and DMG will expect the permittee to provide a complete description of
the damage to the liner from the wind and recertification of the geomembrane liner prior to
placement of any material on that section of the liner.
The water containing sump above the toe berm, the Bump that the underdrain and other pipes
empty into and the outlet pipe in Arequa Gulch (below the Carlton tailings) were inspected.
The sump above the toe berm has had a standpipe installed to try to aid in draining this sump
water into the underdrain and thus into the planned sump below the toe berm eo sediment can
settle out and the water can be drained into Arequa Gulch. A reddish sediment was observed
in the sump below the toe berm. This sediment was in a fan which appeared to come from the
underdrain corrugated 24-inch pipe. A sediment fan has engulfed the standpipe in the sump
above the toe berm. Water was observed draining into the standpipe via the elite in the aide
of the pipe. This water, at that point where it drains into the standpipe, ie not filtered
with geofabric. Because of these observations, the Division suspects that sediment laden
water ie entering the underdrain via the standpipe and possibly loading the underdrain with
fine material. This is unacceptable. The operator will need to provide a plan for Division
review, to close off this unplanned and unpermitted standpipe installation. A plan for how
water that collects above the toe berm will be handled also must be submitted. Both these
issues must be addressed before the standpipe is removed or no later than October 31, 1994.
Please see problem number one on page four of this report.
The 9360 (lowest one used for the pregnant pond liner) anchor trench was checked at 1046
hours and still had water in it ae noted in the inspection report of October 2, 1994. It ie
unwise to allow water to collect and remain in anchor trenches any longer than necessary
since this may contribute to water charging and possible saturation of underlying engineered