ENFORCE37840

• Permit No: M1988112
• IBM Index Class Name: Enforcement
• Doc Date: 5/14/1993
• Doc Name: APPENDIX B ORIGINAL PERMIT APPLICATION COLUMN TEST RESULTS
• Media Type: D
• Archive: No

3.0 TYPES OF COLOIlII TEST
It is ideal to model the tailings deposit, such that thelvolume o!
voids is equal to or greater than 1 liter. For these column sCudies, it
is intended to use 5 inch diameter columns by 12 inches in len~th. This
size xill be adequate to provide the needed volume of vaidsl Also by
maintaining a ratio of approximately 1.0 - 1.5 to 1.0 0!eight to
diameter, the leaching process will allow the leachate to percola a through
the column of tailings in a reasonable time frame.
7.1 SATURATBD TAILINGS COLUlIIi
3.1.1 SAMPLE PLACEMENT WITHIN THE COLUMN

A 2 inch layer of sand would be placed an the bottIom of the
column. This layer of sand would simulate the underdrain s$stem. The
tailings as received would be re-slurried to 50 ~ solids content.
Three lifts of tailings of equal weight and height xould be placed
in the column with bottom drainage closed off at all time during
deposition. The atmosphere within the column would be air. All
drainage, due to settlement o! each lift, would take place to the
surface of the deposit only and the drained liquor xould b~e allowed
to remain at the surface. Each succeeding lift would ~e placed
underwater. At the conclusion of placement of the three lofts, the
tailings liquor would be allowed to drain to slightly bove the
surface of the tailings. The settled density, saturated moisture
content, calculated moisture content, and the total volume of voids
of the deposit would be calculated. At this point the col~mn would
be ready for leaching.
3.1.2 SAMPLE LEACHING
Sample leaching would be carried out suc4 that tt~e top of
tailings are always in a moist state. Enough simulated
rainwater/snowmelt water would be added to the top of the column to
produce one pore volume of leachate. The level of water would be
maintained slightly above the tailings after collecting t~e needed
yore volume. Once the first pore volume has been collected,
additional water would be added at the toy of the column to produce
the second pore volume. This procedure would be continued u~til five
pore volumes have been collected. If needed the hydraulic gradient
could be elevated to speed up the testinq• This xould be accomplished
by increasing the atmospheric pressure above the water.
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