HYDRO29057

• Permit No: M1988112
• IBM Index Class Name: Hydrology
• Doc Name: TABLE OF CONTENTS
• Media Type: D
• Archive: No

A.ppendrs D, Comment Letters and Public Meeting: BMRI Comments (Cont.) Page 3:
2. E. Facility Location -
The longitude should include Wes! at the end ojthe number reference.
Response: This item xals included in the rationale.
3. F. Discharge Points -
Please reference OOIa, 00/b and OOIc as the discharge paint.
Response: The three discharges for 001(00/a, OOlb, and QOIc) are now indicated.
4. N. Facility Description, Paragraph 2
The mill was single ball rather than dual ball.
Response: The description of the mi(1 process has been corrected.
5. lV.A. LB - Wastewater treatment jaciliry description
Please replace the description with the follox~ing paragraph:
The wastewater treatment system drat is used by BMR/includes an enhanced evaporation system that results in no
direct discharge to the Rito Seco during the period of the year x~hen this is feasible to use. During the other times of
the year when a direct discharge to the Rito Seco will occur, the following processes are used: rater softening; three
lined mining/softening ponds; and a rnernbrane separation system. These processes are operational. The treatment
jaciliry is designed to reduce levels ojrnanganese, sulfate, and fluoride and will also maintain other parameters at the
required levels. Other long-term management options may ultimately include in-situ biological treatment. The ultimate
goa( will be the re-establishment of the hydrologic connection between the West Pit and the Rito Seco alluvial
groundwater.
Response: The discussion for the facility x~astewarer treatment system x~as revised to incorporate this information.
6. IV.AJ.B. -Flow Measurement
Although BMRI Itas multiple flow monitoring devices within the treatment [rain jot operational purposes, the only flow
measurement that is applicable jot this discharge permit is theJlaw measurement device in the discharge pipe.
Response: The discussion regarding flow measurement was accordingly revised.
Table IV-I Chemical Additives
BMRI may use barium carbonate as an additive, thus the chemical carne should be included in the additives list. The
purpose for barium carbonate is sulfate precipitation, The final disposition of the barium carbonate is precipitation and
disposal. The purpose for caustic soda should be modified to include pH control and osa[ic acid should be deleted jrorn
the lists since it is not used in the system at all. Soda ash is primarily used for water softening.
Response: The information related to chemicals used a1 the facility was updated.
8. V. Performance History - A.1. -Discharge Moniorng Reports and Self-Monitored Reporting Data
The second sentence should be revised to state that "BMR/ has commenced treatment" rather than "BMRI has been
required to commence treatment. "
Additionally. BMR/ would Wore that there were two ezceedances of pH trigger levels during installation and startup.
These were duly noted in the rationale as a footnote to Table V-1 -Self-Monitoring Results.
Response.• This inforwtion was revised and/or incltaled in the discussion.
9. V. Performance History - D. Facility Improvements
Under the description of other improvements, the portion starting xnth the first bullet should be revised as follows:
"Water removed by combination of enhanced evaporation (summer 1999) and membrane separation (xdnler 1999) "
"Pumping from backfill area and window area (as necessary to maintain hydraulic gradient) "
Elimiwte the description of Phase /I and renumber Phase III to Phase II. Please note shat the Phases referenced in
this section are for facility improvements while the plwses referenced in the following section (V/.A.2) describe the
phases ojtlte Initial Phase and Long-tenn Water Management Programs.
Response: 77iis discussion section was revised.