INSPEC04903

• Permit No: M1977215
• IBM Index Class Name: Inspection
• Doc Date: 4/22/1998
• Doc Name: MINERALS PROGRAM INSPECTION REPORT
• Inspection Date: 4/8/1998
• Media Type: D
• Archive: No

(Page 2)
MINE ID # OR PROSPECTING ID # M-77-215
INSPECTION DATE 4-8-98 INSPECTOR'S INITIALS SSS
This partial inspection was conducted to evaluate the 9360 portal seal proposed location.
The site was inspected to verify preparations for the monolithic concrete portal seal pour,
including forming installation and verification of the drain pipe specifications. The
groundwater tracer injection system was also tested during this inspection.
The miners were installing saddle sets between each existing full timber set in the vicinity
of the proposed portal seal. The miners indicated these timber sets are intended to keep the
adit opening stable for approximately four more years.
The concrete pour forms were in place and braced with three large steel angle braces on the
outside of each. An access panel was cut into each form for access to the adit inby the seal
location. The outby form has several holes cut in it and has steel pipes placed radially
through the seal area and into the sides, top, and bottom of the pour location to aid in
drilling for grout injection. One half of the radially placed pipes extend into the sides
of the seal location approximately 'h of the distance from the outby form and the inby form.
The other half of the pipes extend to the sides of the seal location approximately ~/, of the
distance from the outby form to the inby form.
Concrete injection pipes were in~place. These steel pipes are approximately 6 inches in
diameter and extend from the portal side of the outby form, through that form. Between the
forms, the pipes turn upward 90 degrees and extend into the void above the timber sets that
was created by caving that occurred when lagging between the timber sets was removed to
create a good earth/concrete contact around the seal. One of these two pipes is the actual
concrete injection pipe. This pipe terminates approximately one foot below the top of the
caved area. The other pipe is a termed a phantom pipe. This pipe terminates approximately
e inches below the top of the caved area. During concrete pumping, the phantom pipe serves
as an indicator of when the seal area is nearly filled with concrete. The concrete flows out
of the phantom pipe when the concrete level has risen to within eight of the top of the seal
area.
The stainless steel discharge pipe was in place, through the seal area, in the lower right
corner of the forms (when looking into the adit). The pipe has two three inch tall stainless
steel collars welded onto it that are located within the area to be filled with concrete,
The inby end of the pipe is located within a sandbag type dam structure which is used to keep
water off of the seal area until the seal is finished and the discharge valve is closed.
Holes in the concrete forms will be filled with polyurethane foam to prevent seepage of
concrete during the injection.
Mine water discharge from the adit was estimated at approximately 5 - 10 gpm and was
temporarily being discharged, by pump, to the infiltration trench.
A zone, in the seal injection area, between two timber sets, had most of the lagging cleared
away. The operator was instructed to ensure that, at the time of injection of the concrete,
that this zone between these two timber sets is completely cleaned of all wood, etc. for the
full circumference of the adit. This zone will allow for a debris free contact between the
concrete and the circumference of the adit with no intrusions which could serve as conduits
for water penetration of the seal. The operator was instructed to perform the remaining
cleanup of the injection area and to submit photographic evidence, to the Division, of
completion of the cleanup.