2023-10-03_REVISION - M1977344 (22)

Home Browse Search

Red Creek Quarry Baseline Water Investigation Section 7 7-2 DRAFT for review purposes only. Use of contents on this sheet is subject to the limitations specified at the end of this docu ment. during the first quarterly sampling event (3Q 2022). No photograph was taken at visual observation location 012 during the third quarterly sampling event (1Q 2023). • The upstream surface water sample SW RC1 was collected from the Stilling Well during the first quarterly sampling event (3Q 2022). • During the first quarterly sampling event (3Q 2022), the surface water duplicate was split between SW RC1 (Stilling Well) and SW Seep with most of the duplicate sample collected from the seep location. • During the first quarterly sampling event (3Q 2022), the groundwater field duplicate sample was split between two wells (Well 1 and Well 3). • The full suite of field parameters was inadvertently not recorded from the surface water sites for the first sampling event (3Q 2022). • During the first sampling event (3Q 2022) parameters total alkalinity and TDS were inadvertently collected from Well 4 on three separated dates (8/11/2022, 8/12/2022, and 9/6/2022) and SW RC2 on two separate dates (8/31/2022 and 9/6/2022). • Depth to water measurements were inadvertently not recorded from Well 2N for the first sampling event (3Q 2022). • The hexavalent chromium analyses have a 24-hour hold time. Several samples were not analyzed within the hold time and were qualified during the first four quarterly sampling events. • Sample coolers were submitted above temperature for the fifth quarterly sampling event (3Q 2023). The radio chemical and oil & grease results for the groundwater samples were qualified due to sample temperature. 7.3 Recommendations for Continued Monitoring It is recommended that monitoring continue on a reduced scale until mine development commences. The interim monitoring program is based on review of the baseline water quality statistics in Appendix H and the hydrogeology of the site. Interim monitoring should be conducted on the Site annually during the third calendar quarter. Groundwater quality samples should be collected from Well 1 and Well 3 to continue monitor groundwater quality upgradient and downgradient of the Red Creek seep. Surface water quality samples should be collected from the SW SEEP and SW RC2 surface water locations to monitor surface water quality from the seep where groundwater is discharging to the surface and the furthest downstream location to monitor the water quality within the Red Creek drainage. The analyte list for the interim monitoring program contains inorganic, dissolved metals, and radiological constituents with naturally occurring elevated concentrations (Table 7-1). Constituents that were below the detection limit for all five quarters of baseline data, had no applicable water quality standard or were detected at an order of magnitude or more below the water quality standard concentration have been eliminated from the interim monitoring analyte list. It is also recommended that groundwater level data be continue using the installed pressure transducers during the interim monitoring program. Red Creek flow data is to be collected at the flume using the installed pressure transducer. The frequency at which the transducer data is downloaded and reviewed should be quarterly.