[sheet: Cover]

Field	Value
Document Title	Ridgecrest Copper-Molybdenum Mine — 30-Year Remediation Milestone Schedule
Date Prepared	February 10, 2025
Prepared By	Calderwood & Harkness LLP (Matter No. 1039-00003)
In Coordination With	Pinnacle Creek Environmental, LLC (Dr. Astrid Bergmann, P.E.)
Client	Torchlight Mining Corp. (TSX: TRC / NYSE: TRC)
Operating Entity	Torchlight Mining (U.S.) Inc. / Ridgecrest Mine Holdings, LLC (MT SOS ID: E1042738)
Site Address	14200 Ridgecrest Mine Road, Drummond, Granite County, Montana 59832
Site Area	~3,200 acres (mine footprint); ~8,700 acres (total controlled property)
Consent Decree Reference	United States of America et al. v. Torchlight Mining Corp. et al., Civil Action No. 9:24-cv-00087-DWM, U.S. District Court for the District of Montana, Missoula Division
Judge	Hon. Donald W. Molloy (Senior Judge)
Ridgecrest AOC Docket No.	CERCLA-08-2022-0039
Negotiated Remediation Cost (Nominal)	$198,600,000 over 30 years
NPV (3% discount Rate)	$134,900,000 (NPV factor 0.6795)
TMC Estimate	$187,500,000
EPA Estimate	$224,000,000
Remedy Construction Commencement	June 14, 2027
End of Remediation Obligation	June 14, 2055 (30 years from Effective Date)
Effective Date of Consent Decree	June 14, 2025 (30 days after expected entry date of May 15, 2025)
Financial Assurance (Total)	$245,000,000 (Surety Bond $165.0M, Bond No. ISA-ENV-2025-08934, Ironbark Surety of America, Inc. + Remediation Trust $80.0M, Trust No. LTC-REM-2025-1177, Larchfield Trust Company, N.A.)
Independent Monitor	Verdant Analytics, Inc. (Dr. Kamal Osei)
EPA Project Coordinator	Dr. Samuel Tesfaye, EPA Region 8
Government Technical Expert	Dr. Patricia Voss, Cascade Geosciences, Inc.
Status	DRAFT — Subject to final consent decree entry

[sheet: Key Dates Summary]

Milestone ID	Date	Description	Consent Decree Section	Responsible Party	Status
PRE-01	1978-01-01	Ridgecrest Mine begins operations	Background	TMC	Historical
PRE-02	2019-12-31	Active mining ceases at Ridgecrest	Background	TMC	Complete
PRE-03	2021-01-15	EPA commences removal action at Ridgecrest	Background	EPA	Complete
PRE-04	2022-09-15	Ridgecrest AOC executed (Docket No. CERCLA-08-2022-0039)	Background	TMC / EPA	Complete
PRE-05	2023-05-30	EPA completes Ridgecrest removal action ($14.3M total cost)	Background	EPA	Complete
PRE-06	2023-09-12	EPA issues Notice of Violation (NOV) to TMC	Background	EPA	Complete
PRE-07	2024-01-18	DOJ files complaint (Civil Action No. 9:24-cv-00087-DWM)	Background	DOJ	Complete
PRE-08	2025-02-19	Consent decree lodged with Court; 30-day public comment period begins	§ III	DOJ / TMC	Complete
PRE-09	2025-03-21	Public comment period closes	§ III	Court	Complete
PRE-10	2025-04-28	Court hearing on motion for entry of consent decree	§ III	Court	Pending
PRE-11	2025-05-15	Expected entry of consent decree	§ III	Court	Pending
PRE-12	2025-06-14	Effective Date (30 days after entry, per § IV)	§ IV	—	Pending
PRE-13	2025-07-14	First civil penalty installment due ($7.875M — Ridgecrest share: $3.55M)	§ V.A	TMC	Pending
PRE-14	2025-09-12	Deadline to establish Remediation Trust Fund and post financial assurance ($245.0M total)	§ VIII	TMC / Ironbark / Larchfield	Pending
PRE-15	2025-12-14	Deadline to submit Ridgecrest Remedial Action Work Plan (final)	§ VI.A.1	TMC / Pinnacle Creek	Pending
PRE-16	2027-06-14	Commencement of Ridgecrest remedy construction	§ VI.A.3	TMC	Pending
PRE-17	2055-06-14	End of 30-year remediation obligation	§ VI.A.12	TMC	Pending

[sheet: 30-Year Milestone Schedule]

Year	Period Start	Period End	Phase	Milestone Description	Consent Decree Section	Deliverable / Action	Responsible Party	Annual Cost Estimate ($M)	Cumulative Cost Estimate ($M)	5-Year Benchmark	Verification / Reporting
1	2027-06-14	2028-06-14	Phase 1 — Construction & Active Remediation	Commence remedy construction; mobilize AMD treatment system; begin tailings impoundment stabilization grading; install monitoring well network expansion	§ VI.A.3	Construction mobilization report; initial AMD treatment system design-build contract execution	TMC / Pinnacle Creek	18.5	18.5	5-Year Benchmark 1 (Years 1–5): Complete AMD treatment plant construction, tailings cap Phase 1, initial Flint Creek water quality improvement targets	Quarterly progress reports to EPA (Dr. Samuel Tesfaye); Verdant Analytics quarterly audit
2	2028-06-14	2029-06-14	Phase 1 — Construction & Active Remediation	Continue AMD treatment plant construction; commence tailings impoundment cap installation (Phase 1 — 106 acres); initiate Flint Creek diversion channel engineering	§ VI.A.3	AMD treatment plant 50% completion certificate; tailings cap Phase 1 design submittal	TMC / Pinnacle Creek	22	40.5	Quarterly progress reports; Verdant Analytics quarterly audit
3	2029-06-14	2030-06-14	Phase 1 — Construction & Active Remediation	Complete AMD treatment plant construction and commissioning; continue tailings cap Phase 1 installation; begin Flint Creek diversion channel construction	§ VI.A.4	AMD treatment plant commissioning report; performance testing (target: dissolved copper < 0.0087 mg/L in effluent)	TMC / Pinnacle Creek	24	64.5	Quarterly progress reports; Verdant Analytics quarterly audit; first annual Verdant public report
4	2030-06-14	2031-06-14	Phase 1 — Construction & Active Remediation	Operate AMD treatment plant at full capacity; complete tailings cap Phase 1 (106 acres); continue Flint Creek diversion channel; begin tailings cap Phase 2 design (106 acres)	§ VI.A.4	Tailings cap Phase 1 completion certification; Flint Creek diversion 50% completion report	TMC / Pinnacle Creek	19.5	84	Quarterly progress reports; Verdant Analytics quarterly audit
5	2031-06-14	2032-06-14	Phase 1 — Construction & Active Remediation	Complete Flint Creek diversion channel; commence tailings cap Phase 2 installation; AMD treatment plant operations and optimization; 5-Year Benchmark 1 compliance assessment	§ VI.A.5	5-Year Performance Report; Flint Creek diversion completion certification; Benchmark 1 compliance documentation submitted to EPA and Court	TMC / Pinnacle Creek / Verdant Analytics	16	100	BENCHMARK 1 ASSESSMENT: AMD treatment plant operational; tailings cap Phase 1 complete (106 acres); Flint Creek water quality — dissolved copper trending toward chronic aquatic life standard	5-Year Benchmark Report to Court; Verdant Analytics annual public report; EPA review and determination
6	2032-06-14	2033-06-14	Phase 2 — Extended Remediation & Monitoring	Continue tailings cap Phase 2 (106 acres); AMD treatment plant O&M; begin design for tailings cap Phase 3 (106 acres); enhanced groundwater monitoring	§ VI.A.6	Tailings cap Phase 2 progress report; annual groundwater monitoring report	TMC / Pinnacle Creek	12.5	112.5	5-Year Benchmark 2 (Years 6–10): Complete tailings cap Phases 2 & 3, achieve Flint Creek interim water quality targets, groundwater containment verification	Quarterly progress reports; Verdant Analytics quarterly audit
7	2033-06-14	2034-06-14	Phase 2 — Extended Remediation & Monitoring	Complete tailings cap Phase 2; commence tailings cap Phase 3 installation; continue AMD treatment; Flint Creek in-stream monitoring	§ VI.A.6	Tailings cap Phase 2 completion certification; Phase 3 construction mobilization	TMC / Pinnacle Creek	11	123.5	Quarterly reports; Verdant audit
8	2034-06-14	2035-06-14	Phase 2 — Extended Remediation & Monitoring	Continue tailings cap Phase 3; AMD treatment plant O&M; begin evaluation of long-term AMD treatment optimization	§ VI.A.6	Phase 3 progress report; AMD treatment optimization study	TMC / Pinnacle Creek	9.5	133	Quarterly reports; Verdant audit
9	2035-06-14	2036-06-14	Phase 2 — Extended Remediation & Monitoring	Complete tailings cap Phase 3 (total 318 acres capped of 425-acre impoundment); begin tailings cap Phase 4 design (107 acres — final phase)	§ VI.A.7	Phase 3 completion certification; Phase 4 design submittal; groundwater trend analysis	TMC / Pinnacle Creek	8.5	141.5	Quarterly reports; Verdant audit
10	2036-06-14	2037-06-14	Phase 2 — Extended Remediation & Monitoring	Commence tailings cap Phase 4; AMD treatment plant O&M; 5-Year Benchmark 2 compliance assessment	§ VI.A.7	5-Year Performance Report; Benchmark 2 compliance documentation; tailings cap cumulative status report	TMC / Pinnacle Creek / Verdant Analytics	8	149.5	BENCHMARK 2 ASSESSMENT: Tailings cap Phases 1–3 complete (318 acres); Phase 4 underway; Flint Creek interim targets met; groundwater plume contained	5-Year Benchmark Report to Court; Verdant annual report; EPA determination
11	2037-06-14	2038-06-14	Phase 3 — Long-Term O&M & Monitoring	Complete tailings cap Phase 4 installation (107 acres); AMD treatment plant O&M; ongoing Flint Creek and groundwater monitoring	§ VI.A.8	Phase 4 progress report; annual monitoring report	TMC / Pinnacle Creek	6.5	156	Quarterly reports; Verdant audit
12	2038-06-14	2039-06-14	Phase 3 — Long-Term O&M & Monitoring	Complete tailings cap Phase 4 (all 425 acres capped); AMD treatment O&M; site reclamation and revegetation monitoring	§ VI.A.8	Tailings cap Phase 4 completion certification; full cap integrity assessment	TMC / Pinnacle Creek	5	161	Quarterly reports; Verdant audit
13	2039-06-14	2040-06-14	Phase 3 — Long-Term O&M & Monitoring	AMD treatment plant O&M; tailings cap maintenance; ecological restoration monitoring; groundwater trend verification	§ VI.A.8	Annual monitoring and maintenance report; ecological restoration progress report	TMC / Pinnacle Creek	4.5	165.5	Quarterly reports; Verdant audit
14	2040-06-14	2041-06-14	Phase 3 — Long-Term O&M & Monitoring	Continued AMD treatment O&M; tailings cap inspections and repairs as needed; Flint Creek biological monitoring	§ VI.A.8	Annual monitoring report; biological assessment report for Flint Creek	TMC / Pinnacle Creek	3.5	169	Quarterly reports; Verdant audit
15	2041-06-14	2042-06-14	Phase 3 — Long-Term O&M & Monitoring	AMD treatment plant long-term O&M; tailings cap maintenance and inspections; Flint Creek and groundwater monitoring; 5-Year Benchmark 3 compliance assessment	§ VI.A.8	5-Year Performance Report; Benchmark 3 compliance documentation	TMC / Pinnacle Creek / Verdant Analytics	2.5	171.5	BENCHMARK 3 ASSESSMENT: All tailings cap phases complete (425 acres); AMD treatment meeting effluent standards consistently; Flint Creek final water quality targets on track	5-Year Benchmark Report to Court
16	2042-06-14	2043-06-14	Phase 3 — Long-Term O&M & Monitoring	AMD treatment O&M; routine tailings cap inspections; Flint Creek and groundwater monitoring; begin passive treatment feasibility evaluation	§ VI.A.9	Annual monitoring report; passive treatment feasibility study — Phase 1	TMC / Pinnacle Creek	3	174.5	Quarterly reports; Verdant audit
17	2043-06-14	2044-06-14	Phase 3 — Long-Term O&M & Monitoring	Continue AMD treatment O&M; passive treatment pilot study if warranted; tailings cap maintenance; environmental monitoring	§ VI.A.9	Annual monitoring report; passive treatment feasibility study — Phase 2	TMC / Pinnacle Creek	2.8	177.3	Quarterly reports; Verdant audit
18	2044-06-14	2045-06-14	Phase 3 — Long-Term O&M & Monitoring	AMD treatment O&M; tailings cap maintenance; Flint Creek biological and chemical monitoring; groundwater trend confirmation	§ VI.A.9	Annual monitoring report; groundwater trend analysis update	TMC / Pinnacle Creek	2.7	180	Quarterly reports; Verdant audit
19	2045-06-14	2046-06-14	Phase 3 — Long-Term O&M & Monitoring	AMD treatment O&M; routine cap and infrastructure maintenance; monitoring well network assessment; comprehensive data review	§ VI.A.9	Annual monitoring report; monitoring well network optimization study	TMC / Pinnacle Creek	2.5	182.5	Quarterly reports; Verdant audit
20	2046-06-14	2047-06-14	Phase 3 — Long-Term O&M & Monitoring	Continued O&M; monitoring well network assessment; possible transition to passive AMD treatment evaluation; 5-Year Benchmark 4 compliance assessment	§ VI.A.9	5-Year Performance Report; Benchmark 4 compliance documentation; passive treatment feasibility study	TMC / Pinnacle Creek	2.5	185	BENCHMARK 4 ASSESSMENT: Sustained compliance with all surface water and groundwater standards; evaluate passive treatment transition	5-Year Benchmark Report to Court
21	2047-06-14	2048-06-14	Phase 4 — Transition & Pre-Termination	Continue AMD treatment (active or passive per feasibility outcome); tailings cap maintenance; routine monitoring; initiate long-term stewardship planning	§ VI.A.10	Annual monitoring report; long-term stewardship plan — draft	TMC / Pinnacle Creek	2	187	5-Year Benchmark 5 (Years 21–25): Sustained compliance; termination planning initiated	Quarterly reports; Verdant audit
22	2048-06-14	2049-06-14	Phase 4 — Transition & Pre-Termination	Continued O&M; monitoring; institutional controls verification; long-term stewardship plan finalization	§ VI.A.10	Annual monitoring report; long-term stewardship plan — final	TMC / Pinnacle Creek	1.9	188.9	Quarterly reports; Verdant audit
23	2049-06-14	2050-06-14	Phase 4 — Transition & Pre-Termination	O&M continuation; cap integrity assessment; comprehensive environmental monitoring; termination readiness data compilation	§ VI.A.10	Annual monitoring report; cap integrity assessment report	TMC / Pinnacle Creek	1.8	190.7	Quarterly reports; Verdant audit
24	2050-06-14	2051-06-14	Phase 4 — Transition & Pre-Termination	O&M continuation; monitoring; begin assembling Certification of Completion documentation; pre-termination site assessment	§ VI.A.10	Annual monitoring report; pre-termination site assessment — draft	TMC / Pinnacle Creek	1.8	192.5	Quarterly reports; Verdant audit

25	2051-06-14	2052-06-14	Phase 4 — Transition & Pre-Termination	Continue O&M; maintain tailings cap; comprehensive site-wide monitoring; 5-Year Benchmark 5 compliance assessment; begin preparation of termination petition package	§ VI.A.10	5-Year Performance Report; Benchmark 5 compliance documentation; preliminary termination readiness assessment	TMC / Pinnacle Creek	1.5	194	BENCHMARK 5 ASSESSMENT: All performance standards sustained; site conditions stable; initiate termination planning	5-Year Benchmark Report to Court
26	2052-06-14	2053-06-14	Phase 4 — Termination Eligibility	O&M continuation; monitoring; finalize termination petition documentation; coordinate with EPA on Certification of Completion requirements	§ VI.A.11	Annual monitoring report; termination petition — draft for EPA review	TMC / Pinnacle Creek	1.1	195.1	5-Year Benchmark 6 (Years 26–30): Certification of Completion; termination petition	Quarterly reports; Verdant audit
27	2053-06-14	2054-06-14	Phase 4 — Termination Eligibility	O&M continuation; monitoring; EPA review of draft termination materials; address EPA comments and information requests	§ VI.A.11	Annual monitoring report; revised termination petition package	TMC / Pinnacle Creek	1	196.1	Quarterly reports; Verdant audit
28	2054-06-14	2055-06-14	Phase 4 — Termination Eligibility	O&M continuation; final confirmation monitoring; Verdant Analytics comprehensive final compliance assessment; submit formal termination petition to Court	§ VI.A.12	Formal termination petition filed; Verdant final compliance report — draft	TMC / Pinnacle Creek / Verdant Analytics	0.9	197	Quarterly reports; Verdant final compliance audit
29	2055-06-14	2056-06-14	Phase 4 — Termination Eligibility	Final O&M activities; confirmation monitoring; Court review of termination petition; respond to Court and EPA inquiries	§ VI.A.12 / § XII	Annual monitoring report; supplemental information as requested by Court/EPA	TMC / Pinnacle Creek	0.6	197.6	Quarterly reports; Verdant audit
30	2056-06-14	2057-06-14	Phase 4 — Termination Eligibility	Final year of 30-year obligation; complete final monitoring cycle; prepare and submit Certification of Completion to EPA and Court; Verdant Analytics final compliance report; 5-Year Benchmark 6 (final)	§ VI.A.12 / § XII (Termination)	Certification of Completion application; final 5-Year Performance Report; termination petition (termination no sooner than 5 years after completion of all remedial construction)	TMC / Pinnacle Creek / Verdant Analytics / EPA	1	198.6	BENCHMARK 6 (FINAL): All remediation objectives achieved; Certification of Completion sought from EPA; Court approval of termination	Final Verdant report; EPA Certification of Completion review

[sheet: 5-Year Benchmark Summary]

Benchmark #	Period	Calendar Years	Phase	Key Performance Criteria	Target Water Quality Metrics	Tailings Cap Status	Cost for Period ($M)	Cumulative Cost ($M)	NPV of Period Cost ($M, 3%)	Consent Decree Section	Reporting Requirements
1	Years 1–5	June 2027 – June 2032	Phase 1 — Construction & Active Remediation	AMD treatment plant operational; tailings cap Phase 1 complete; Flint Creek diversion channel complete	Dissolved copper in AMD effluent < 0.0087 mg/L; molybdenum < 0.5 mg/L; selenium < 0.005 mg/L; sulfate trending below 2,000 mg/L	Phase 1 complete: 106 of 425 acres capped (25%)	100	100	86.3	§ VI.A.3–5	5-Year Benchmark Report; Verdant Analytics annual public reports; quarterly EPA progress reports
2	Years 6–10	June 2032 – June 2037	Phase 2 — Extended Remediation & Monitoring	Tailings cap Phases 2–3 complete; Phase 4 commenced; Flint Creek interim targets met; groundwater plume contained	Flint Creek in-stream dissolved copper < 0.05 mg/L (interim); groundwater monitoring well copper < 1.0 mg/L at compliance boundary	Phases 1–3 complete: 318 of 425 acres capped (75%); Phase 4 underway	49.5	149.5	36.9	§ VI.A.6–7	5-Year Benchmark Report; Verdant reports
3	Years 11–15	June 2037 – June 2042	Phase 3 — Long-Term O&M & Monitoring	All tailings cap phases complete (425 acres); AMD treatment sustained; Flint Creek final targets on track	Flint Creek dissolved copper approaching chronic standard 0.0087 mg/L; groundwater stable/declining trends	All phases complete: 425 of 425 acres capped (100%)	22	171.5	14.2	§ VI.A.8	5-Year Benchmark Report
4	Years 16–20	June 2042 – June 2047	Phase 3 — Long-Term O&M & Monitoring	Sustained compliance; passive treatment feasibility evaluation	All water quality standards met consistently	Maintenance and inspections only	13.5	185	7.5	§ VI.A.9	5-Year Benchmark Report
5	Years 21–25	June 2047 – June 2052	Phase 4 — Transition & Pre-Termination	Sustained compliance; termination planning initiated	All standards met; trending data confirms long-term stability	Maintenance and inspections only	9	194	4.3	§ VI.A.10	5-Year Benchmark Report; preliminary termination readiness assessment
6	Years 26–30	June 2052 – June 2057	Phase 4 — Termination Eligibility	Certification of Completion; termination petition	Final confirmation of all performance standards	Final cap integrity verification	4.6	198.6	1.9	§ VI.A.12 / § XII	Final 5-Year Report; Certification of Completion application
TOTAL	Years 1–30	June 2027 – June 2057	All Phases	—	—	—	198.6	198.6	151.1	—	—

[sheet: Cost Allocation by Remedy Compo]

Remedy Component	Description	Nominal Cost ($M)	% of Total	Construction Period	O&M Period	Construction Cost ($M)	O&M Cost ($M)
AMD Treatment System	Design, construction, commissioning, and 30-year operation of active acid mine drainage treatment plant to reduce dissolved copper (from avg. 47 mg/L to < 0.0087 mg/L), molybdenum (from 1.2 mg/L to < 0.5 mg/L), selenium (from 0.082 mg/L to < 0.005 mg/L), and sulfate (from 3,400 mg/L to < 2,000 mg/L)	72.4	36.5	Years 1–3	Years 4–30	38	34.4
Tailings Impoundment Cap	Engineering, installation, and maintenance of engineered cap over 425-acre tailings impoundment in four phases (Phase 1: 106 ac, Phase 2: 106 ac, Phase 3: 106 ac, Phase 4: 107 ac) to eliminate seepage to Flint Creek	58.2	29.3	Years 1–10	Years 11–30	48	10.2
Flint Creek Water Quality Restoration	Diversion channel construction, bank stabilization, and long-term in-stream monitoring along Flint Creek (note: separate from the $5.5M Flint Creek Watershed Restoration SEP)	24.8	12.5	Years 1–5	Years 6–30	16	8.8
Groundwater Monitoring & Containment	Monitoring well network (existing + new wells), groundwater sampling (quarterly/semi-annual), plume delineation updates, and potential extraction/treatment if containment not achieved passively	18.6	9.4	Years 1–5 (installation)	Years 1–30 (monitoring)	5	13.6
RCRA Corrective Action (SX-EW Circuit)	Investigation, closure, and remediation of hazardous waste from the solvent-extraction/electrowinning circuit, including soil removal and disposal	12	6	Years 1–4	Years 5–10	9.5	2.5
Site Reclamation & Ecological Restoration	Grading, topsoil placement, revegetation, habitat restoration of open-pit area and disturbed lands within the 3,200-acre mine footprint	8.6	4.3	Years 3–10	Years 11–20	5.5	3.1
Project Management, Reporting & Regulatory Compliance	Overall project management by Pinnacle Creek Environmental, regulatory reporting, permit compliance, coordination with EPA Project Coordinator (Dr. Samuel Tesfaye) and independent monitor (Verdant Analytics)	4	2	Years 1–30	Years 1–30	1.5	2.5
TOTAL	All remedy components — Ridgecrest Copper-Molybdenum Mine	198.6	100	—	—	123.5	75.1

[sheet: Contaminant Targets]

Contaminant	Medium	Baseline Concentration	Applicable Standard / Target	Regulatory Basis	Interim Target (Year 5)	Interim Target (Year 10)	Final Target (Year 30)	Monitoring Frequency
Dissolved Copper	Surface Water (AMD discharge / Flint Creek)	Avg. 47 mg/L	0.0087 mg/L (Montana chronic aquatic life standard)	CWA § 301 / Montana WQS	< 0.0087 mg/L in AMD treatment effluent; < 0.05 mg/L in Flint Creek (interim)	< 0.0087 mg/L in Flint Creek at downstream compliance point	Sustained compliance with 0.0087 mg/L at all compliance points	Monthly (AMD effluent); Quarterly (Flint Creek stations)
Molybdenum	Surface Water	Avg. 1.2 mg/L	0.5 mg/L (site-specific target per consent decree)	Consent Decree § VI.A	< 0.5 mg/L in AMD effluent	< 0.5 mg/L sustained	< 0.5 mg/L sustained	Monthly (AMD effluent)
Selenium	Surface Water	Avg. 0.082 mg/L	0.005 mg/L (Montana WQS)	CWA / Montana WQS	< 0.02 mg/L (interim)	< 0.005 mg/L	< 0.005 mg/L sustained	Monthly (AMD effluent); Quarterly (Flint Creek)
Sulfate	Surface Water	Avg. 3,400 mg/L	2,000 mg/L (interim); site-specific per consent decree	Consent Decree § VI.A	< 2,500 mg/L (interim)	< 2,000 mg/L	< 2,000 mg/L sustained	Monthly
Dissolved Copper	Groundwater (monitoring wells)	Varies (up to 85 mg/L at source area wells)	Site-specific groundwater cleanup levels per consent decree	RCRA / CERCLA	Plume contained; no expansion beyond current boundary	Declining trends at all compliance wells	Meet groundwater cleanup levels at compliance boundary	Quarterly
Arsenic	Groundwater (monitoring wells)	Varies (up to 0.15 mg/L at source area wells)	0.010 mg/L (MCL)	SDWA / CERCLA	Plume contained; concentrations declining at source	< 0.050 mg/L at compliance boundary wells	< 0.010 mg/L at compliance boundary wells	Quarterly
Hazardous Waste Residuals (SX-EW)	Soil / Waste	Characterization per RCRA § 3004	RCRA closure standards; land disposal restrictions met	RCRA §§ 3004, 3005	Waste removal 50% complete	Closure certification obtained	Post-closure monitoring complete	Semi-annual during closure; annual post-closure
Total Suspended Solids (TSS)	Surface Water (Flint Creek)	Avg. 120 mg/L during high-flow events	30 mg/L (Montana WQS — 30-day average)	CWA / Montana WQS	< 80 mg/L (interim, post-diversion channel)	< 30 mg/L at downstream compliance point	< 30 mg/L sustained	Quarterly; event-based during high flow

[sheet: Cover]
Field | Value
Document Title | Ridgecrest Copper-Molybdenum Mine — 30-Year Remediation Milestone Schedule
Date Prepared | February 10, 2025
Prepared By | Calderwood & Harkness LLP (Matter No. 1039-00003)
In Coordination With | Pinnacle Creek Environmental, LLC (Dr. Astrid Bergmann, P.E.)
Client | Torchlight Mining Corp. (TSX: TRC / NYSE: TRC)
Operating Entity | Torchlight Mining (U.S.) Inc. / Ridgecrest Mine Holdings, LLC (MT SOS ID: E1042738)
Site Address | 14200 Ridgecrest Mine Road, Drummond, Granite County, Montana 59832
Site Area | ~3,200 acres (mine footprint); ~8,700 acres (total controlled property)
Consent Decree Reference | United States of America et al. v. Torchlight Mining Corp. et al., Civil Action No. 9:24-cv-00087-DWM, U.S. District Court for the District of Montana, Missoula Division
Judge | Hon. Donald W. Molloy (Senior Judge)
Ridgecrest AOC Docket No. | CERCLA-08-2022-0039
Negotiated Remediation Cost (Nominal) | $198,600,000 over 30 years
NPV (3% discount Rate) | $134,900,000 (NPV factor 0.6795)
TMC Estimate | $187,500,000
EPA Estimate | $224,000,000
Remedy Construction Commencement | June 14, 2027
End of Remediation Obligation | June 14, 2055 (30 years from Effective Date)
Effective Date of Consent Decree | June 14, 2025 (30 days after expected entry date of May 15, 2025)
Financial Assurance (Total) | $245,000,000 (Surety Bond $165.0M, Bond No. ISA-ENV-2025-08934, Ironbark Surety of America, Inc. + Remediation Trust $80.0M, Trust No. LTC-REM-2025-1177, Larchfield Trust Company, N.A.)
Independent Monitor | Verdant Analytics, Inc. (Dr. Kamal Osei)
EPA Project Coordinator | Dr. Samuel Tesfaye, EPA Region 8
Government Technical Expert | Dr. Patricia Voss, Cascade Geosciences, Inc.
Status | DRAFT — Subject to final consent decree entry
[sheet: Key Dates Summary]
Milestone ID | Date | Description | Consent Decree Section | Responsible Party | Status
PRE-01 | 1978-01-01 | Ridgecrest Mine begins operations | Background | TMC | Historical
PRE-02 | 2019-12-31 | Active mining ceases at Ridgecrest | Background | TMC | Complete
PRE-03 | 2021-01-15 | EPA commences removal action at Ridgecrest | Background | EPA | Complete
PRE-04 | 2022-09-15 | Ridgecrest AOC executed (Docket No. CERCLA-08-2022-0039) | Background | TMC / EPA | Complete
PRE-05 | 2023-05-30 | EPA completes Ridgecrest removal action ($14.3M total cost) | Background | EPA | Complete
PRE-06 | 2023-09-12 | EPA issues Notice of Violation (NOV) to TMC | Background | EPA | Complete
PRE-07 | 2024-01-18 | DOJ files complaint (Civil Action No. 9:24-cv-00087-DWM) | Background | DOJ | Complete
PRE-08 | 2025-02-19 | Consent decree lodged with Court; 30-day public comment period begins | § III | DOJ / TMC | Complete
PRE-09 | 2025-03-21 | Public comment period closes | § III | Court | Complete
PRE-10 | 2025-04-28 | Court hearing on motion for entry of consent decree | § III | Court | Pending
PRE-11 | 2025-05-15 | Expected entry of consent decree | § III | Court | Pending
PRE-12 | 2025-06-14 | Effective Date (30 days after entry, per § IV) | § IV | — | Pending
PRE-13 | 2025-07-14 | First civil penalty installment due ($7.875M — Ridgecrest share: $3.55M) | § V.A | TMC | Pending
PRE-14 | 2025-09-12 | Deadline to establish Remediation Trust Fund and post financial assurance ($245.0M total) | § VIII | TMC / Ironbark / Larchfield | Pending
PRE-15 | 2025-12-14 | Deadline to submit Ridgecrest Remedial Action Work Plan (final) | § VI.A.1 | TMC / Pinnacle Creek | Pending
PRE-16 | 2027-06-14 | Commencement of Ridgecrest remedy construction | § VI.A.3 | TMC | Pending
PRE-17 | 2055-06-14 | End of 30-year remediation obligation | § VI.A.12 | TMC | Pending
[sheet: 30-Year Milestone Schedule]
Year | Period Start | Period End | Phase | Milestone Description | Consent Decree Section | Deliverable / Action | Responsible Party | Annual Cost Estimate ($M) | Cumulative Cost Estimate ($M) | 5-Year Benchmark | Verification / Reporting
1 | 2027-06-14 | 2028-06-14 | Phase 1 — Construction & Active Remediation | Commence remedy construction; mobilize AMD treatment system; begin tailings impoundment stabilization grading; install monitoring well network expansion | § VI.A.3 | Construction mobilization report; initial AMD treatment system design-build contract execution | TMC / Pinnacle Creek | 18.5 | 18.5 | 5-Year Benchmark 1 (Years 1–5): Complete AMD treatment plant construction, tailings cap Phase 1, initial Flint Creek water quality improvement targets | Quarterly progress reports to EPA (Dr. Samuel Tesfaye); Verdant Analytics quarterly audit
2 | 2028-06-14 | 2029-06-14 | Phase 1 — Construction & Active Remediation | Continue AMD treatment plant construction; commence tailings impoundment cap installation (Phase 1 — 106 acres); initiate Flint Creek diversion channel engineering | § VI.A.3 | AMD treatment plant 50% completion certificate; tailings cap Phase 1 design submittal | TMC / Pinnacle Creek | 22 | 40.5 | Quarterly progress reports; Verdant Analytics quarterly audit
3 | 2029-06-14 | 2030-06-14 | Phase 1 — Construction & Active Remediation | Complete AMD treatment plant construction and commissioning; continue tailings cap Phase 1 installation; begin Flint Creek diversion channel construction | § VI.A.4 | AMD treatment plant commissioning report; performance testing (target: dissolved copper < 0.0087 mg/L in effluent) | TMC / Pinnacle Creek | 24 | 64.5 | Quarterly progress reports; Verdant Analytics quarterly audit; first annual Verdant public report
4 | 2030-06-14 | 2031-06-14 | Phase 1 — Construction & Active Remediation | Operate AMD treatment plant at full capacity; complete tailings cap Phase 1 (106 acres); continue Flint Creek diversion channel; begin tailings cap Phase 2 design (106 acres) | § VI.A.4 | Tailings cap Phase 1 completion certification; Flint Creek diversion 50% completion report | TMC / Pinnacle Creek | 19.5 | 84 | Quarterly progress reports; Verdant Analytics quarterly audit
5 | 2031-06-14 | 2032-06-14 | Phase 1 — Construction & Active Remediation | Complete Flint Creek diversion channel; commence tailings cap Phase 2 installation; AMD treatment plant operations and optimization; 5-Year Benchmark 1 compliance assessment | § VI.A.5 | 5-Year Performance Report; Flint Creek diversion completion certification; Benchmark 1 compliance documentation submitted to EPA and Court | TMC / Pinnacle Creek / Verdant Analytics | 16 | 100 | BENCHMARK 1 ASSESSMENT: AMD treatment plant operational; tailings cap Phase 1 complete (106 acres); Flint Creek water quality — dissolved copper trending toward chronic aquatic life standard | 5-Year Benchmark Report to Court; Verdant Analytics annual public report; EPA review and determination
6 | 2032-06-14 | 2033-06-14 | Phase 2 — Extended Remediation & Monitoring | Continue tailings cap Phase 2 (106 acres); AMD treatment plant O&M; begin design for tailings cap Phase 3 (106 acres); enhanced groundwater monitoring | § VI.A.6 | Tailings cap Phase 2 progress report; annual groundwater monitoring report | TMC / Pinnacle Creek | 12.5 | 112.5 | 5-Year Benchmark 2 (Years 6–10): Complete tailings cap Phases 2 & 3, achieve Flint Creek interim water quality targets, groundwater containment verification | Quarterly progress reports; Verdant Analytics quarterly audit
7 | 2033-06-14 | 2034-06-14 | Phase 2 — Extended Remediation & Monitoring | Complete tailings cap Phase 2; commence tailings cap Phase 3 installation; continue AMD treatment; Flint Creek in-stream monitoring | § VI.A.6 | Tailings cap Phase 2 completion certification; Phase 3 construction mobilization | TMC / Pinnacle Creek | 11 | 123.5 | Quarterly reports; Verdant audit
8 | 2034-06-14 | 2035-06-14 | Phase 2 — Extended Remediation & Monitoring | Continue tailings cap Phase 3; AMD treatment plant O&M; begin evaluation of long-term AMD treatment optimization | § VI.A.6 | Phase 3 progress report; AMD treatment optimization study | TMC / Pinnacle Creek | 9.5 | 133 | Quarterly reports; Verdant audit
9 | 2035-06-14 | 2036-06-14 | Phase 2 — Extended Remediation & Monitoring | Complete tailings cap Phase 3 (total 318 acres capped of 425-acre impoundment); begin tailings cap Phase 4 design (107 acres — final phase) | § VI.A.7 | Phase 3 completion certification; Phase 4 design submittal; groundwater trend analysis | TMC / Pinnacle Creek | 8.5 | 141.5 | Quarterly reports; Verdant audit
10 | 2036-06-14 | 2037-06-14 | Phase 2 — Extended Remediation & Monitoring | Commence tailings cap Phase 4; AMD treatment plant O&M; 5-Year Benchmark 2 compliance assessment | § VI.A.7 | 5-Year Performance Report; Benchmark 2 compliance documentation; tailings cap cumulative status report | TMC / Pinnacle Creek / Verdant Analytics | 8 | 149.5 | BENCHMARK 2 ASSESSMENT: Tailings cap Phases 1–3 complete (318 acres); Phase 4 underway; Flint Creek interim targets met; groundwater plume contained | 5-Year Benchmark Report to Court; Verdant annual report; EPA determination
11 | 2037-06-14 | 2038-06-14 | Phase 3 — Long-Term O&M & Monitoring | Complete tailings cap Phase 4 installation (107 acres); AMD treatment plant O&M; ongoing Flint Creek and groundwater monitoring | § VI.A.8 | Phase 4 progress report; annual monitoring report | TMC / Pinnacle Creek | 6.5 | 156 | Quarterly reports; Verdant audit
12 | 2038-06-14 | 2039-06-14 | Phase 3 — Long-Term O&M & Monitoring | Complete tailings cap Phase 4 (all 425 acres capped); AMD treatment O&M; site reclamation and revegetation monitoring | § VI.A.8 | Tailings cap Phase 4 completion certification; full cap integrity assessment | TMC / Pinnacle Creek | 5 | 161 | Quarterly reports; Verdant audit
13 | 2039-06-14 | 2040-06-14 | Phase 3 — Long-Term O&M & Monitoring | AMD treatment plant O&M; tailings cap maintenance; ecological restoration monitoring; groundwater trend verification | § VI.A.8 | Annual monitoring and maintenance report; ecological restoration progress report | TMC / Pinnacle Creek | 4.5 | 165.5 | Quarterly reports; Verdant audit
14 | 2040-06-14 | 2041-06-14 | Phase 3 — Long-Term O&M & Monitoring | Continued AMD treatment O&M; tailings cap inspections and repairs as needed; Flint Creek biological monitoring | § VI.A.8 | Annual monitoring report; biological assessment report for Flint Creek | TMC / Pinnacle Creek | 3.5 | 169 | Quarterly reports; Verdant audit
15 | 2041-06-14 | 2042-06-14 | Phase 3 — Long-Term O&M & Monitoring | AMD treatment plant long-term O&M; tailings cap maintenance and inspections; Flint Creek and groundwater monitoring; 5-Year Benchmark 3 compliance assessment | § VI.A.8 | 5-Year Performance Report; Benchmark 3 compliance documentation | TMC / Pinnacle Creek / Verdant Analytics | 2.5 | 171.5 | BENCHMARK 3 ASSESSMENT: All tailings cap phases complete (425 acres); AMD treatment meeting effluent standards consistently; Flint Creek final water quality targets on track | 5-Year Benchmark Report to Court
16 | 2042-06-14 | 2043-06-14 | Phase 3 — Long-Term O&M & Monitoring | AMD treatment O&M; routine tailings cap inspections; Flint Creek and groundwater monitoring; begin passive treatment feasibility evaluation | § VI.A.9 | Annual monitoring report; passive treatment feasibility study — Phase 1 | TMC / Pinnacle Creek | 3 | 174.5 | Quarterly reports; Verdant audit
17 | 2043-06-14 | 2044-06-14 | Phase 3 — Long-Term O&M & Monitoring | Continue AMD treatment O&M; passive treatment pilot study if warranted; tailings cap maintenance; environmental monitoring | § VI.A.9 | Annual monitoring report; passive treatment feasibility study — Phase 2 | TMC / Pinnacle Creek | 2.8 | 177.3 | Quarterly reports; Verdant audit
18 | 2044-06-14 | 2045-06-14 | Phase 3 — Long-Term O&M & Monitoring | AMD treatment O&M; tailings cap maintenance; Flint Creek biological and chemical monitoring; groundwater trend confirmation | § VI.A.9 | Annual monitoring report; groundwater trend analysis update | TMC / Pinnacle Creek | 2.7 | 180 | Quarterly reports; Verdant audit
19 | 2045-06-14 | 2046-06-14 | Phase 3 — Long-Term O&M & Monitoring | AMD treatment O&M; routine cap and infrastructure maintenance; monitoring well network assessment; comprehensive data review | § VI.A.9 | Annual monitoring report; monitoring well network optimization study | TMC / Pinnacle Creek | 2.5 | 182.5 | Quarterly reports; Verdant audit
20 | 2046-06-14 | 2047-06-14 | Phase 3 — Long-Term O&M & Monitoring | Continued O&M; monitoring well network assessment; possible transition to passive AMD treatment evaluation; 5-Year Benchmark 4 compliance assessment | § VI.A.9 | 5-Year Performance Report; Benchmark 4 compliance documentation; passive treatment feasibility study | TMC / Pinnacle Creek | 2.5 | 185 | BENCHMARK 4 ASSESSMENT: Sustained compliance with all surface water and groundwater standards; evaluate passive treatment transition | 5-Year Benchmark Report to Court
21 | 2047-06-14 | 2048-06-14 | Phase 4 — Transition & Pre-Termination | Continue AMD treatment (active or passive per feasibility outcome); tailings cap maintenance; routine monitoring; initiate long-term stewardship planning | § VI.A.10 | Annual monitoring report; long-term stewardship plan — draft | TMC / Pinnacle Creek | 2 | 187 | 5-Year Benchmark 5 (Years 21–25): Sustained compliance; termination planning initiated | Quarterly reports; Verdant audit
22 | 2048-06-14 | 2049-06-14 | Phase 4 — Transition & Pre-Termination | Continued O&M; monitoring; institutional controls verification; long-term stewardship plan finalization | § VI.A.10 | Annual monitoring report; long-term stewardship plan — final | TMC / Pinnacle Creek | 1.9 | 188.9 | Quarterly reports; Verdant audit
23 | 2049-06-14 | 2050-06-14 | Phase 4 — Transition & Pre-Termination | O&M continuation; cap integrity assessment; comprehensive environmental monitoring; termination readiness data compilation | § VI.A.10 | Annual monitoring report; cap integrity assessment report | TMC / Pinnacle Creek | 1.8 | 190.7 | Quarterly reports; Verdant audit
24 | 2050-06-14 | 2051-06-14 | Phase 4 — Transition & Pre-Termination | O&M continuation; monitoring; begin assembling Certification of Completion documentation; pre-termination site assessment | § VI.A.10 | Annual monitoring report; pre-termination site assessment — draft | TMC / Pinnacle Creek | 1.8 | 192.5 | Quarterly reports; Verdant audit
25 | 2051-06-14 | 2052-06-14 | Phase 4 — Transition & Pre-Termination | Continue O&M; maintain tailings cap; comprehensive site-wide monitoring; 5-Year Benchmark 5 compliance assessment; begin preparation of termination petition package | § VI.A.10 | 5-Year Performance Report; Benchmark 5 compliance documentation; preliminary termination readiness assessment | TMC / Pinnacle Creek | 1.5 | 194 | BENCHMARK 5 ASSESSMENT: All performance standards sustained; site conditions stable; initiate termination planning | 5-Year Benchmark Report to Court
26 | 2052-06-14 | 2053-06-14 | Phase 4 — Termination Eligibility | O&M continuation; monitoring; finalize termination petition documentation; coordinate with EPA on Certification of Completion requirements | § VI.A.11 | Annual monitoring report; termination petition — draft for EPA review | TMC / Pinnacle Creek | 1.1 | 195.1 | 5-Year Benchmark 6 (Years 26–30): Certification of Completion; termination petition | Quarterly reports; Verdant audit
27 | 2053-06-14 | 2054-06-14 | Phase 4 — Termination Eligibility | O&M continuation; monitoring; EPA review of draft termination materials; address EPA comments and information requests | § VI.A.11 | Annual monitoring report; revised termination petition package | TMC / Pinnacle Creek | 1 | 196.1 | Quarterly reports; Verdant audit
28 | 2054-06-14 | 2055-06-14 | Phase 4 — Termination Eligibility | O&M continuation; final confirmation monitoring; Verdant Analytics comprehensive final compliance assessment; submit formal termination petition to Court | § VI.A.12 | Formal termination petition filed; Verdant final compliance report — draft | TMC / Pinnacle Creek / Verdant Analytics | 0.9 | 197 | Quarterly reports; Verdant final compliance audit
29 | 2055-06-14 | 2056-06-14 | Phase 4 — Termination Eligibility | Final O&M activities; confirmation monitoring; Court review of termination petition; respond to Court and EPA inquiries | § VI.A.12 / § XII | Annual monitoring report; supplemental information as requested by Court/EPA | TMC / Pinnacle Creek | 0.6 | 197.6 | Quarterly reports; Verdant audit
30 | 2056-06-14 | 2057-06-14 | Phase 4 — Termination Eligibility | Final year of 30-year obligation; complete final monitoring cycle; prepare and submit Certification of Completion to EPA and Court; Verdant Analytics final compliance report; 5-Year Benchmark 6 (final) | § VI.A.12 / § XII (Termination) | Certification of Completion application; final 5-Year Performance Report; termination petition (termination no sooner than 5 years after completion of all remedial construction) | TMC / Pinnacle Creek / Verdant Analytics / EPA | 1 | 198.6 | BENCHMARK 6 (FINAL): All remediation objectives achieved; Certification of Completion sought from EPA; Court approval of termination | Final Verdant report; EPA Certification of Completion review
[sheet: 5-Year Benchmark Summary]
Benchmark # | Period | Calendar Years | Phase | Key Performance Criteria | Target Water Quality Metrics | Tailings Cap Status | Cost for Period ($M) | Cumulative Cost ($M) | NPV of Period Cost ($M, 3%) | Consent Decree Section | Reporting Requirements
1 | Years 1–5 | June 2027 – June 2032 | Phase 1 — Construction & Active Remediation | AMD treatment plant operational; tailings cap Phase 1 complete; Flint Creek diversion channel complete | Dissolved copper in AMD effluent < 0.0087 mg/L; molybdenum < 0.5 mg/L; selenium < 0.005 mg/L; sulfate trending below 2,000 mg/L | Phase 1 complete: 106 of 425 acres capped (25%) | 100 | 100 | 86.3 | § VI.A.3–5 | 5-Year Benchmark Report; Verdant Analytics annual public reports; quarterly EPA progress reports
2 | Years 6–10 | June 2032 – June 2037 | Phase 2 — Extended Remediation & Monitoring | Tailings cap Phases 2–3 complete; Phase 4 commenced; Flint Creek interim targets met; groundwater plume contained | Flint Creek in-stream dissolved copper < 0.05 mg/L (interim); groundwater monitoring well copper < 1.0 mg/L at compliance boundary | Phases 1–3 complete: 318 of 425 acres capped (75%); Phase 4 underway | 49.5 | 149.5 | 36.9 | § VI.A.6–7 | 5-Year Benchmark Report; Verdant reports
3 | Years 11–15 | June 2037 – June 2042 | Phase 3 — Long-Term O&M & Monitoring | All tailings cap phases complete (425 acres); AMD treatment sustained; Flint Creek final targets on track | Flint Creek dissolved copper approaching chronic standard 0.0087 mg/L; groundwater stable/declining trends | All phases complete: 425 of 425 acres capped (100%) | 22 | 171.5 | 14.2 | § VI.A.8 | 5-Year Benchmark Report
4 | Years 16–20 | June 2042 – June 2047 | Phase 3 — Long-Term O&M & Monitoring | Sustained compliance; passive treatment feasibility evaluation | All water quality standards met consistently | Maintenance and inspections only | 13.5 | 185 | 7.5 | § VI.A.9 | 5-Year Benchmark Report
5 | Years 21–25 | June 2047 – June 2052 | Phase 4 — Transition & Pre-Termination | Sustained compliance; termination planning initiated | All standards met; trending data confirms long-term stability | Maintenance and inspections only | 9 | 194 | 4.3 | § VI.A.10 | 5-Year Benchmark Report; preliminary termination readiness assessment
6 | Years 26–30 | June 2052 – June 2057 | Phase 4 — Termination Eligibility | Certification of Completion; termination petition | Final confirmation of all performance standards | Final cap integrity verification | 4.6 | 198.6 | 1.9 | § VI.A.12 / § XII | Final 5-Year Report; Certification of Completion application
TOTAL | Years 1–30 | June 2027 – June 2057 | All Phases | — | — | — | 198.6 | 198.6 | 151.1 | — | —
[sheet: Cost Allocation by Remedy Compo]
Remedy Component | Description | Nominal Cost ($M) | % of Total | Construction Period | O&M Period | Construction Cost ($M) | O&M Cost ($M)
AMD Treatment System | Design, construction, commissioning, and 30-year operation of active acid mine drainage treatment plant to reduce dissolved copper (from avg. 47 mg/L to < 0.0087 mg/L), molybdenum (from 1.2 mg/L to < 0.5 mg/L), selenium (from 0.082 mg/L to < 0.005 mg/L), and sulfate (from 3,400 mg/L to < 2,000 mg/L) | 72.4 | 36.5 | Years 1–3 | Years 4–30 | 38 | 34.4
Tailings Impoundment Cap | Engineering, installation, and maintenance of engineered cap over 425-acre tailings impoundment in four phases (Phase 1: 106 ac, Phase 2: 106 ac, Phase 3: 106 ac, Phase 4: 107 ac) to eliminate seepage to Flint Creek | 58.2 | 29.3 | Years 1–10 | Years 11–30 | 48 | 10.2
Flint Creek Water Quality Restoration | Diversion channel construction, bank stabilization, and long-term in-stream monitoring along Flint Creek (note: separate from the $5.5M Flint Creek Watershed Restoration SEP) | 24.8 | 12.5 | Years 1–5 | Years 6–30 | 16 | 8.8
Groundwater Monitoring & Containment | Monitoring well network (existing + new wells), groundwater sampling (quarterly/semi-annual), plume delineation updates, and potential extraction/treatment if containment not achieved passively | 18.6 | 9.4 | Years 1–5 (installation) | Years 1–30 (monitoring) | 5 | 13.6
RCRA Corrective Action (SX-EW Circuit) | Investigation, closure, and remediation of hazardous waste from the solvent-extraction/electrowinning circuit, including soil removal and disposal | 12 | 6 | Years 1–4 | Years 5–10 | 9.5 | 2.5
Site Reclamation & Ecological Restoration | Grading, topsoil placement, revegetation, habitat restoration of open-pit area and disturbed lands within the 3,200-acre mine footprint | 8.6 | 4.3 | Years 3–10 | Years 11–20 | 5.5 | 3.1
Project Management, Reporting & Regulatory Compliance | Overall project management by Pinnacle Creek Environmental, regulatory reporting, permit compliance, coordination with EPA Project Coordinator (Dr. Samuel Tesfaye) and independent monitor (Verdant Analytics) | 4 | 2 | Years 1–30 | Years 1–30 | 1.5 | 2.5
TOTAL | All remedy components — Ridgecrest Copper-Molybdenum Mine | 198.6 | 100 | — | — | 123.5 | 75.1
[sheet: Contaminant Targets]
Contaminant | Medium | Baseline Concentration | Applicable Standard / Target | Regulatory Basis | Interim Target (Year 5) | Interim Target (Year 10) | Final Target (Year 30) | Monitoring Frequency
Dissolved Copper | Surface Water (AMD discharge / Flint Creek) | Avg. 47 mg/L | 0.0087 mg/L (Montana chronic aquatic life standard) | CWA § 301 / Montana WQS | < 0.0087 mg/L in AMD treatment effluent; < 0.05 mg/L in Flint Creek (interim) | < 0.0087 mg/L in Flint Creek at downstream compliance point | Sustained compliance with 0.0087 mg/L at all compliance points | Monthly (AMD effluent); Quarterly (Flint Creek stations)
Molybdenum | Surface Water | Avg. 1.2 mg/L | 0.5 mg/L (site-specific target per consent decree) | Consent Decree § VI.A | < 0.5 mg/L in AMD effluent | < 0.5 mg/L sustained | < 0.5 mg/L sustained | Monthly (AMD effluent)
Selenium | Surface Water | Avg. 0.082 mg/L | 0.005 mg/L (Montana WQS) | CWA / Montana WQS | < 0.02 mg/L (interim) | < 0.005 mg/L | < 0.005 mg/L sustained | Monthly (AMD effluent); Quarterly (Flint Creek)
Sulfate | Surface Water | Avg. 3,400 mg/L | 2,000 mg/L (interim); site-specific per consent decree | Consent Decree § VI.A | < 2,500 mg/L (interim) | < 2,000 mg/L | < 2,000 mg/L sustained | Monthly
Dissolved Copper | Groundwater (monitoring wells) | Varies (up to 85 mg/L at source area wells) | Site-specific groundwater cleanup levels per consent decree | RCRA / CERCLA | Plume contained; no expansion beyond current boundary | Declining trends at all compliance wells | Meet groundwater cleanup levels at compliance boundary | Quarterly
Arsenic | Groundwater (monitoring wells) | Varies (up to 0.15 mg/L at source area wells) | 0.010 mg/L (MCL) | SDWA / CERCLA | Plume contained; concentrations declining at source | < 0.050 mg/L at compliance boundary wells | < 0.010 mg/L at compliance boundary wells | Quarterly
Hazardous Waste Residuals (SX-EW) | Soil / Waste | Characterization per RCRA § 3004 | RCRA closure standards; land disposal restrictions met | RCRA §§ 3004, 3005 | Waste removal 50% complete | Closure certification obtained | Post-closure monitoring complete | Semi-annual during closure; annual post-closure
Total Suspended Solids (TSS) | Surface Water (Flint Creek) | Avg. 120 mg/L during high-flow events | 30 mg/L (Montana WQS — 30-day average) | CWA / Montana WQS | < 80 mg/L (interim, post-diversion channel) | < 30 mg/L at downstream compliance point | < 30 mg/L sustained | Quarterly; event-based during high flow

[sheet: Cover]

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