Slide 1: Stream Restoration: The Stibnite Gold Project
STREAM RESTORATION THE STIBNITE GOLD PROJECT Valley County, Idaho Rob Richardson – Principal Geomorphologist, Rio ASE
Slide 2: Reclamation vs Restoration
RECLAMATION RESTORATION Reclamation: stable, static, Restoration: naturally little to no change; may not dynamic, deformable, mimic natural conditions resilient; mimics natural conditions Meadow Creek, ID Meadow Creek, ID
Slide 3: Fisheries Goals
FISHERIES GOALS Goals Results Restoration of volitional passage Restoration of passage • Early passage, during mine operations, through • Early on in the project and a long closure, and beyond. awaited permanent solution Restoration of spawning and rearing habitat Access to miles of improved habitat
Slide 4: Current Conditions
CURRENT CONDITIONS Rendering of existing Yellow Pine pit looking upstream EFSFSR Fish Barrier Yellow Pine Pit 4
Slide 5: During Mining
DURING MINING Rendering of proposed tunnel alignment looking downstream Downstream (North) transition back to EFSFSR EFSFSR Tunnel, 0.9-mi. long Upstream (South) diversion into tunnel 5
Slide 6: Stream Access
Existing cascade passage barrier Proposed new stream access for migratory fish: During Operations: 6.4 miles After Restoration: 6.0 miles STREAM ACCESS (based on intrinsic potential for Chinook Salmon and Steelhead) Enhancement Enhancement Restoration No Change
Slide 7: Access Upper EFSFSR
ACCESS UPPER EFSFSR
Slide 8: EFSFSR and Meadow Creek
EFSFSR and MEADOW CREEK Restored/Enhanced EFSFSR and Meadow Creek • Passage enhancements • Engineered log jams • Other spawning and rearing habitat enhancements • Blowout Creek no longer contributing excess sediment • Spent leach ore and Bradley tailings no longer contributing metals loading 8
Slide 9: Stream Design
STREAM DESIGN Goal: Reclaim and/or restore disturbed streams and floodplain from historical and proposed mining activities to improve habitat conditions for aquatic species and mitigate for project impacts. Stream Design Report: Section 1.3
Slide 10: Stream Design Objectives
STREAM DESIGN OBJECTIVES General Stream Design Objectives Stream Design Project Area • Provide fish passage above Yellow Pine pit • Restore high-quality stream channels over the top of proposed mine features at closure o Develop a stable yet functionally dynamic and resilient stream channel and floo
Slide 11: Stream Design Objectives
STREAM DESIGN OBJECTIVES Objectives Reach-Specific Stream Design Objectives • Biological (species of interest: Chinook salmon, steelhead, bull trout, and Westslope cutthroat trout) o Fish Distribution o Fish use periodicity o Habitat Requirements o Intrinsic Potential (Anadromous Salmonids) • Physic
Slide 12: Stream Design Process
STREAM DESIGN PROCESS Reach Delineation Stream Design Approach: • Same process for all streams • Project Area reach delineation • Reference site analysis • Develop physical design criteria o Reference site data o Empirical formulae o Published design guidelines • Assign biological objectives based o
Slide 13: Stream Design Process
STREAM DESIGN PROCESS Reference Sites Stream Design Approach: • Same process for all streams • Project Area reach delineation • Reference site analysis • Develop physical design criteria o Reference site data o Empirical formulae o Published design guidelines • Assign biological objectives based on
Slide 14: Stream Design Process
STREAM DESIGN PROCESS Design Criteria Stream Design Approach: • Same process for all streams • Project Area reach delineation • Reference site analysis • Develop physical design criteria o Reference site data o Empirical formulae Including Watershed Condition o Published design guidelines Indicators
Slide 15: Stream Design Criteria
STREAM DESIGN CRITERIA Biological Objectives Stream Design Approach: • Same process for all streams • Project Area reach delineation • Reference site analysis • Develop physical design criteria o Reference site data o Empirical formulae o Published design guidelines • Assign biological objectives ba
Slide 16: Stream Design Criteria
STREAM DESIGN CRITERIA Biological Objectives Stream Design Approach: • Same process for all streams • Project Area reach delineation • Reference site analysis • Develop physical design criteria o Reference site data o Empirical formulae o Published design guidelines • Assign biological objectives ba
Slide 17: EFSFSR Over YPP
EFSFSR OVER YPP East Fork South Fork Salmon River (EFSFSR) 18
Slide 18: EFSFSR Over YPP
EFSFSR OVER YPP Restoration Objectives • Restore migratory fish passage through YPP to upstream reaches • Target isolated spawning and rearing habitat creation • Allow geomorphically appropriate natural channel process (migration, avulsion, scour, deposition) • Increase hydraulic and geomorphic dive
Slide 19: EFSFSR Over YPP
EFSFSR OVER YPP Floodplain is 5-10x the bankfull channel width EFSFSR over YPP Example Proposed Stream Liner Details (DRAFT) Layers of Material Over the Liner Total Liner Depth Approximate Reach Mine Facility Protection Armor Layer Stream Bed and Below the Floodplain Liner Width (ft)* (Transition) L
Slide 20: Final Restoration
FINAL RESTORATION 21
Slide 21: Restoration Examples: Building New Banks
RESTORATION EXAMPLES Building New Banks Brush Layer Fabric Encapsulated Soil Lift (FESL) 22
Slide 22: Restoration Examples: Building New Banks
RESTORATION EXAMPLES Building New Banks Fabric Encapsulated Soil Lift 1-Year After Construction Big Springs Creek, 23 ID
Slide 23: Restoration Examples: Building New Banks
RESTORATION EXAMPLES Building New Banks Roughened Bank Structure 24
Slide 24: Restoration Examples: Building New Banks
RESTORATION EXAMPLES Building New Banks Roughened Bank Structure Construction 1- Year After Lemhi River, 25 ID
Slide 25: Restoration Examples: Habitat Features
RESTORATION EXAMPLES Habitat Features Large Woody Debris 26
Slide 26: Restoration Examples: Habitat Features
RESTORATION EXAMPLES Habitat Features Large Woody Debris Construction Immediately After Construction Yankee Fork River, 27 ID
Slide 27: Restoration Examples: Grade Controls
RESTORATION EXAMPLES Grade Controls Constructed Riffle 28
Slide 28: Restoration Examples: Grade Controls
RESTORATION EXAMPLES Grade Controls Immediately After Construction Lemhi River, ID Constructed Riffle Construction 29
Slide 29: Restoration Examples: Catherine Creek Oregon
RESTORATION EXAMPLES Catherine Creek Oregon During Construction 30
Slide 30: Restoration Examples: Catherine Creek Oregon
RESTORATION EXAMPLES Catherine Creek Oregon 1-Year After Construction 31
Slide 31: Restoration Examples: Catherine Creek Oregon
RESTORATION EXAMPLES Catherine Creek Oregon 5-Years After Construction 32
Slide 32: Performance Criteria
PERFORMANCE CRITERIA Performance Standards Overall Performance Standards • From the CMP (March 8, 2019) section 11.1 • Stream Design (as-built conditions) • Physical Channel Conditions • Riparian Vegetation • Functions and Values o Evaluated using Stream Functional Assessment Note: Timeline based on
Slide 33: Stream Functional Assessment
STREAM FUNCTIONAL ASSESSMENT
Slide 34: Stream Functional Assessment: Introduction
STREAM FUNCTIONAL ASSESSMENT Introduction The Stream Functional Assessment (SFA) Ledger was developed in coordination with natural resource management and regulatory agencies to be used for the Stibnite Gold Project (SGP) to: • Track the impacts/benefits to streams before, during and after mining fo
Slide 35: Stream Functional Assessment: Framework - Elements
STREAM FUNCTIONAL ASSESSMENT Framework - Elements The SFA uses a modified version of the Watershed Condition Indicators Matrix (WCI Matrix) (USFS 2003, 2010) along with several fish use indicators to evaluate stream condition by measuring up to 20 elements that reflect specific functional indicators
Slide 36: Stream Functional Assessment: Framework - Elements
STREAM FUNCTIONAL ASSESSMENT Framework - Elements • The 20 elements analyzed within the SFA Ledger are based on field data, GIS desktop analysis, modeling estimates and professional judgment • Baseline data were collected between 2012 and 2019 from a number of sources and originated from on-site mon
Slide 37: Framework: SFA Reach Generation
STREAM FUNCTIONAL ASSESSMENT Framework – SFA Reach Generation Consistent Reaches Example SFA reach delineation combining hypothetical reaches across phases where reach breaks per phase are identified by black dots on the blue stream line, while the combined reach breaks for the SFA are identified by
Slide 38: Framework: Element Scoring Criteria
STREAM FUNCTIONAL ASSESSMENT Framework – Element Scoring Criteria Indicator Temperature Element (oC) 7DADM Rearing Spawning Rating FA ≤12 ≤12 FR >12 – ≤15 >9 – ≤10 UR >15 >10 Water Quality Granitic Basin <12% 12% - 18% >18% Fine Sediment (%) Non-Granitic Basin < 3% 3% - 6% >6% Chemical Contaminants
Slide 39: Framework: Functional Index
STREAM FUNCTIONAL ASSESSMENT Framework – Functional Index Functional Index (FI) is the normalized weighted average score of scorable elements within each reach as seen in the formula below. Where: FI = Functional Index EWi = Weight of Element i Ei = Score of Element i (1, 2 or 3) Reach score = (sum
Slide 40: Framework: Functional Units
STREAM FUNCTIONAL ASSESSMENT Framework – Functional Units Measured using Functional Units (FU): Quality Quantity 𝐹𝑈 = 𝐹𝐼 ∗ 𝐿𝑒𝑛𝑔𝑡ℎ ∗ (𝑆𝑡𝑟𝑒𝑎𝑚 𝑂𝑟𝑑𝑒𝑟 + 1) Where: FU = Functional Units FI = Functional Index The functional unit is the mitigation currency proposed for the SGP such that…
Slide 41: Stream Functional Assessment: Results
STREAM FUNCTIONAL ASSESSMENT Results
Slide 42: Questions
Questions RioASE.com Rob@RioASE.com Phone: (208) 559-4615 WWW.MIDASGOLDIDAHO.COM EMAIL: info@midasgoldinc.com PHONE: (208) 901-3060