REV07329

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Date: 3/25/1999
• Doc Name: SECTION 4
• Type & Sequence: TR26
• Media Type: D
• Archive: No

~-~,
L~

Table 4-5 Bench-scale Testing Results for Passive Biological Treatment
Constituent BF-2
(2/5/99) Anaerobic Cell
3/8/99 Aerobic Cell
3/8/99 Trickle Cell
3/8/99
pH 7.6 6.4 8.2 8.2
Bicarbonate 217 715 512 397
TDS 1260 1,630 640 540
Calcium 343 410 114 71.7
Fluoride 8.3 113 0.9 1.2
Silica 19.3 69.1 52 51.1
Sulfate 706 264 80.1 82.8
Sulfide not detected 21.3 not detected not detected
Iron <0.019 62.1 2.19 1.8
Manganese 5.31 53.2 4.05 0.411
The aerobic column efficiently removed iron, manganese, silica, and fluoride (Table 4-5).
During the 5 weeks of operation, the physical matrix in the aerobic column became covered with
slimes. The manganese removal efficiency of the aerobic columns also increased with time. In
light of the results of data analysis to date, passive biological treatment systems generally may
require more than 12 weeks to achieve maximum efficiency (Gordon and Burr, 1987).
4.4.4 Additional Water Management Options
Water management in the West Pit must consider not only the chemistry of the backfill water,
but also the hydrology of the groundwater flow from the pit. Two additional options have been
considered for controlling the flow of groundwater from the West Pit: (I) enhanced evaporation,
(2) installation offlow-control structures (e.g., slung walls).
4.4.4.1 Enhanced Evaporation
Enhanced evaporation is considered as a water management option to extract pit water and
facilitate pore water rinse out. This approach would employ natural evaporative effects
8a!!le Mourtlain Resources. Inc.
p:U001671reporrs~marchrptlrrl6wlrmngrmnrch.doc 58
March 11. 1999