PERMFILE138480

• Permit No: M1982090
• IBM Index Class Name: Permit File
• Doc Date: 8/29/1982
• From: CAMP BIRD
• To: MLR
• Media Type: D
• Archive: No

i
STIPULATION N0, 1
Stability Study Of Tailings Pond
•
The tailings pond in present use was originally started in
1964. A starter dam was constructed of slope materials existing on
the mine site, All vegetation and loose debris was removed and the
underpond area compacted, The starter dam was composed of angular
31nch material an~i smaller down to clay size top soil. This material s
was eompacted using caterpillar tractors and loaders.and was 15 feet
wide at the top by 20feet high, Two decant lines were installed heneath
the starter dam with decant towers erected for proper dewatering;(see
plan view map of tailings dewatering system). An underdrainage system
was installed in front of the starter dam which was composed of l to 3
inch angular rock, The original design of the tailings pond was to he •~ -c
raised to a height of 150 feet.
The perm o1: the tailings pond was raised using the centreline
method of berm construction, The tailings slurry was cycloned with
the coarser materials (larger than 50 mesh) being segregated to con-
struct the berm, The berm was raised by moving the cyclone along and
on top of the most: recent lift, Lifts were 4 to 6 foot thick and l5
to 25 feet vide,
In this method of berm construction the slimes and sand inter-
finger (see cross section of pond) on the inside of the embankment,
Several advantages of using the centreline method of tailings dam
building are:
1, None of the embankment is built on previously deposited
loose, fine tailings.
2, Placement and compaction control can he exercised as
required over the fill operation.
3. Underdrainage systems can be installed as the dam is
built. This controlla the line of saturation (the
phreatic line) through the dam and increases stability.
4. The dam can be designed and constructed to whatever degree
of competency that may be required,
5• Usually, the dam can be raised above its original design
height with a minimum of design modifications.
Camp Bird mine rock is of such a hard and dense nature that the
mill grinding circuit produces adequate quantities of coarse sand for
berm construction.
From the present elevation up the berm will be constructed
using the centreline d~awnstrenm method.of cycloned sand raised in
4 to 6 foot lifts. The berm width will be a minimum of 15 feet
and a maximum of 25 feet with outslopes of 2 to 1 and inslopes of