INSPEC27565

• Permit No: C1981018
• IBM Index Class Name: Inspection
• Doc Date: 8/6/1992
• Doc Name: OSM INSPECTION REPORT
• From: OSM
• Inspection Date: 6/23/1992
• Media Type: D
• Archive: No

INSPECTION REPORT 2
well as corresponding permit documentation for that disposal were meeting
regulatory standards. i made an effort at that time to review the documents
and field techniques with company personnel. Their permit refers to
"platelet" construction for the disposal of processing waste which are to
be placed in on horizontal lifts. These platelets combined into a pile do
not result in a horizontal lift. That was obvious during the 1990
inspection. At that time, the operator was opening the number four area.
That area now has over a hundred thousand yards of processing waste laid
down in the pile. Area one, the first disposal site has been reclaimed.
Area two dash three is within 75 8 of being filled. According to Mr.
Chervick, the processing waste being brought into the piles for disposal
has changed in consistency somewhat because more rock is being encounterd
underground. Production has also been increased thus placing more demand
on the processing plant. That being the case, the filter cake material
percentages of reject in the area are now on the rise. i asked him if
that would affect the compaction that is to be attained on the piles. He
said that he was testing for compaction in each of the piles with a nuclear
densiometer on a quarterly basis. He indicated that they have encountered
some difficulty initially with the compaction and occasionally have to go
back through some of the lift laid down and rework it to achieve the 90
percent rate as required in their permit.
Both active piles are being laid down via "platelet construction" with the
major portion of the resulting surface drainage flowing down the center of
the pile. Measurements taken with a clinometer at 100 yard intervals down
the centerline of the pile averaged 9 to 5 percent downgrade to the toe of
the pile on pile #4 as well as pile two dash three. Two dash three slopes
on the toe of the pile have been graded to final grade for the first 100
yards in from the toe of the structure then the average grade noted, 4 to 5
8, on pile 4 was also the same for this area. I also measured slopes 100
yards out from the centerline in both directions. These slopes readings
ran 4 to 5 percent on pile #4 and varied from a minus 2 to 6 percent on
pile two dash three. My findings are included as illustrations in the
report.
Obviously there were some depressions in pile two dash three, the operator
said that they were having a hard time drying out the waste from winter
operation deposits. They had a pile of waste from the winter months placed
on the northeast quadrant of pile two dash three. They said that they did
not want to spread out the material during the winter because they have a
problem compacting it. They said that they did not want to place the
material higher on the pile because it would saturate the entire pile from
top to bottom. I understand but do not agree with the concept of.piling up
waste for the summer drying season. If the pile is built correctly and
waste is spread and worked properly it should work. I realize that
winters there are harsh but other operators in Colorado have done it. If
there is not enough drying time and the material is worked properly another
option remains, - other areas should be opened for disposal to increase the
amount of drying surface.
The comment was made that the "ditches" around the perimeter of the pile
as waste meets original ground are designed structures built for a 100 year
24 hour event. I believe the "agreement" reached with State officials on
other waste areas in the state is for 100 yr 6 hr design standards.
Whatever the case, I would suggest that the ditches be built accordingly.
There also is a ditch in the center island between the two active piles
that is supposed to be constructed to the higher standard. That ditch
really serves no purpose because of the size of area drained. However it
was built to meet the requirements of disposal.
There xas a comment in the mine plan about monitoring water coming out of
the waste disposal pile -if it occurred, for acid or toxic forming