2023-07-28_REPORT - M1988112

• Permit No: M1988112
• IBM Index Class Name: Report
• Doc Date: 7/28/2023
• Doc Name: Annual Tailings Dam Inspection Report
• From: Julio F. Madrid - Colorado Legacy Sites
• To: DRMS
• Annual Report Year: 2023
• Email Name: LJW
• Email Name: THM
• Media Type: D
• Archive: No

San Luis TSF David Carino
2023 Annual Dam Safety Inspection Battle Mountain Resources,Inc.
Table 1 San Luis TSF Piezometer Levels: April 2022 -May 2023
PIEZOMETER ID P6 P7 P8 P9 P10 P11 P12 P13 P14 P15
TOTAL DEPTH(ft)" 72.46 92.50 97.51 72.30 58.30 41.80 41.71 41.34 41.24 41.10
4/27/2022 72.46 92.29 96.58 71.93 57.47 41.40 41.66 41.02 41.24 40.87
5/31/2022 72.46 92.28 96.64 71.94 57.49 41.39 41.65 41.01 1 41.24 40.87
6/30/2022 72.46 92.30 96.62 71.93 57.48 41.41 41.65 41.01 41.24 40.87
7/28/2022 72.46 92.30 96.65 71.94 57.49 41.41 41.65 41.01 41.24 40.87
8/31/2022 72.46 92.50 96.65 71.93 57.49 41.40 41.65 41.00 41.24 40.86
9/29/2022 72.46 92.50 96.65 71.93 57.48 41.40 41.64 41.00 41.24 40.85
10/31/2022 72.46 92.50 96.64 71.92 57.48 41.39 41.65 41.00 41.24 40.86
11/30/2022 72.46 92.50 96.68 71.94 57.47 41.40 41.64 40.99 41.24 40.85
12/30/2022 72.46 92.50 96.67 71.94 57.48 41.40 41.65 41.00 41.24 40.85
1/31/2023 72.46 92.50 96.66 71.95 57.48 41.41 41.63 41.03 41.24 40.84
2/28/2023 72.46 92.50 96.67 71.95 57.47 41.40 41.64 41.00 41.24 40.80
3/30/2023 72.46 92.50 96.67 71.95 57.47 41.40 41.63 41.02 41.24 40.85
4/27/2023 72.46 92.50 96.65 71.95 57.48 41.39 41.63 41.03 41.24 40.86
*Piezometer total depths measured from top of casing
Underdrain: Underdrain flow rates discharging to the seepage collection pond from April 2022
through May 2023 are shown in Table 2, and flow rates from 2016 to 2023 are presented
graphically on Figure 4. Average underdrain flow measurements from 2020-23 (31.7 gpm) are
slightly lower than from 2016-2023 (34.0 gpm).
The underdrain pipes were jet-cleaned in 2014 in conjunction with the first camera inspection of
the accessible downstream ends of the pipes. A second video inspection of the pipe ends was done
without jet cleaning in 2018. The 2018 videos showed some accumulation of sediment and
precipitates in the pipes compared to the 2014 videos, but the pipes were all still flowing (not
clogged). Thus, the observed slight reduction in underdrain flow in recent years is likely due to
ongoing severe regional drought. The pipes were jet-cleaned again on October 5, 2020, and May
10, 2021, with no video inspections. It is recommended that jetting of the pipes and video
inspections be conducted at least every 3 years unless a change in measured drainage flow rates
warrants more frequent cleaning and inspection.
2 Engineering Analytics,Inc.