Draft Mine Closure Plan. 17 October 2018 Longlac & Geraldton

Transcription

1 Draft Mine Closure Plan 17 October 2018 Longlac & Geraldton

2 Project Update Federal EA Decision report was issued on October 1 st and Provincial Report is expected to be issued Oct 22 nd Federal approval is expected to be received in December 2018, and Provincial Approval in Q Permit applications can be submitted once the EA is approved, starting with tree clearing and leachate collection from the MacLeod High Tailings Target is to have all permit approvals required to start major construction in place before Q and all permit approvals for Highway 11 construction prior to Q Based on regulated approval timelines and recent experience on other projects, permit approval timeline ranges from 45 days (Closure Plan) to ~ 12 months (ECA Water) The Closure Plan is the first permit that must be approved before any site work commences. A few additional permits are required prior to commencing Operations 10/16/2018 2

3 What is a Closure Plan? Registering a formal Mine Closure Plan is a first step towards site development, following Ministerial approval of the federal and provincial environmental assessments. All land affected by development must be rehabilitated after the activity has finished. A closure plan outlines how the affected land will be rehabilitated and the costs associated with doing so. A closure plan must be developed and approved by the Ministry of Energy, Northern Development and Mines before mine development can begin. This is a beginning, not an end! The Hardrock Mine is progressing through the EA process and expected to proceed. 10/16/2018 3

4 Site Plan 10/16/2018 4

5 Mine Closure: What happens after mining ends at this site? A conceptual closure plan was developed for the EIS/EA. The plan has been updated based on comments received during the EIS/EA process. Further refinements will come from consultation on this draft. After the EA is approved the Closure Plan will be submitted to MENDM for approval, with financial securities to cover the cost of mine reclamation - before any site development can commence. The site conditions expected once final closure is complete: Buildings will be dismantled and removed, and most mine roads reclaimed. Revegetation will focus on native plant species and habitat creation to encourage the return of wildlife species native to the area. Most access restrictions will be lifted after closure but a boulder fence / earth berm around the open pit will remain for safety. Waste Rock Stockpile benches and top plateau, and the tailings facility, will be revegetated.

6 Run animation video section showing the mine reclamation process 10/16/2018 6

7 Sequence of Mine Closure and Site Reclamation

8 Site overview at end of construction (initial closure plan) 10/16/2018 8

9 Site overview, nearing the end of operations phase 10/16/2018 9

10 Site overview after the pit lake is filled 10/16/

11 Financial Assurance for Mine Closure To ensure that mining companies do not leave exploration or mining sites in poor condition, the Ontario Mining Act requires a formal closure plan to be approved, prior to work commencing on a site. Detailed cost estimates for site reclamation must be included in the closure plan, and financial securities are provided that the government can spend to clean up the site if the miner abandons the property or goes out of business. The closure costs and financial security are reviewed / approved by the Ministry of Energy, Northern Development & Mines (MENDM) The financial security may be staged, increasing over time as the site develops and expands (exploration / construction / operations). 10/16/

12 Summary of previous community comments on mine closure

13 What GGM heard: Community consultation in the EA process Conceptual closure plans were included in the draft EA and final EA packages for review and comment. The current draft of the plan has been expanded to include more background information from the EA and supplemental detail on site reclamation, where available, to meet MENDM requirements. A detailed closure cost estimate is being prepared, with financial security proposed to be staged to increase at: Early site preparation, Full construction, Early operations and Late operations. 10/16/

14 What GGM heard: Questions raised by communities in EA comments (1) Key areas of interest included: 1. Water Quality: water management and water quality during closure, TMF dam stability, duration to fill the pit, seepage from the historic MacLeod and Hardrock mine tailings 2. Vegetation: Encourage plants with medicinal / food values, changes in plant communities, monitoring of recovery of wetlands, control of invasive plants. 3. Habitat: Loss of waterfowl nesting and wildlife habitat, post-closure environmental monitoring, ongoing engagement about habitat, effects of climate change on plants used for reclamation, management of soils for site reclamation. 4. Progressive site remediation: Look for opportunities to carry out reclamation work during operations. 10/16/

15 What GGM heard: Questions raised by communities in EA comments (2) 5. Communication and Community Involvement: Community engagement in mine closure planning, environmental monitoring and adaptive management decisions, communication of site hazards, could project assets (power plant) be re-used to meet community needs? 6. Vegetation and habitat: Plants of interest to aboriginal communities, soil structure to support stable plant communities, evaluation of wildlife habitat following closure, remediation options for the TMF at closure, replacement habitat for lost wetlands. 7. Long Term Site Hazards: Monitoring historic tailings seepage, stability monitoring of the TMF dams & rock piles, stability and function of the pit lake. 10/16/

16 Final Closure and Site Reclamation

17 Final Closure and site reclamation #1 Overview All site buildings will be dismantled and removed, and most mine roads reclaimed. Revegetation will focus on native plant species and habitat creation to encourage the return of wildlife species native to the area. Aggregate pits will be regraded and revegetated when no longer needed, as required by applicable permits. Most site access restrictions will be lifted after closure but a boulder fence / earth berm around the open pit will remain for safety. Through the MENDM Closure Plan process, financial securities will remain in place until applicable mine closure obligations are met and the site is certified as being adequately rehabilitated. Red Willow Wiikehn Labrador Tea 10/16/

18 Final Closure and site reclamation: Mine Pit From EA Appendix F5 Water will be pumped from the TMF, water collection ponds, and excess water from the Southwest Arm of Kenogamisis Lake, to reduce the pit filling time to 16 years. The pit will become a deep density-stratified lake, with low oxygen in the lower part aiding the removal of metals from the water. The upper part of the pit lake will be fresh water and will discharge to the SW Arm of Kenogamisis Lake. 10/16/

19 Final Closure and site reclamation: Tailings Facility The tailings facility (TMF) will be considered closed and under passive care once: the internal pond has been drained and surface water is discharging to the environment it has been shown that the TMF is stable the internal water table has come to a naturalized level. The TMF embankments will be constructed of waste rock which will not produce dust or surface erosion. No revegetation of the outer slope is planned. The surface of the tailings will be covered by earth and revegetated to reduce potential surface erosion, and reduce contact between surface water and tailings. 10/16/

20 Final Closure and site reclamation: TMF Water TMF Internal Pond Discharge channel Excess water in the TMF will be pumped to the Mosher Shaft to help fill the mine pit, allow for TMF rehabilitation, and provide time for water quality to improve. Once the mine pit has filled and the TMF water meets quality standards, the TMF spillway will be lowered to drain excess water to the Goldfield Creek diversion. The reclaim pond will remove sediment from water runoff within the TMF. A constructed wetland could be added to improve water quality. 10/16/

21 Final Closure and site reclamation: TMF Perimeter Ponds TMF Perimeter Ponds Water in the perimeter ponds and ditches will continue to be pumped back to the TMF until it meets acceptable discharge criteria. These ponds may have constructed wetland systems added if further polishing of water quality is required prior to discharge. When no longer needed, these ponds will be emptied and their bottom sediment tested. If the sediment meets regulatory requirements, it may be used for site rehabilitation. Otherwise, the removed sediment will either be deposited in the TMF or sent to an approved offsite landfill. The perimeter berms of the water collection system will be graded to match surrounding land and the ponds filled to grade with clean material. 10/16/

22 Optimization trials during the mine operating phase Constructed wetlands for passive treatment of wastewater Compendium of Sanitation Systems and Technologies - (2nd Revised Edition). Swiss Federal Institute of Aquatic Science and Technology (Eawag), Duebendorf, Switzerland. Revegetation trials for mine reclamation an.ca/livingwithlakes/research/projects/rehabilitation-of-plantcommunities-in-the-hudsons-bay-lowlands-after-mining/ 22

23 Final Closure and site reclamation: Waste Rock Piles WRSAs must be rehabilitated to meet physical and chemical stability criteria. As each pile reaches capacity, the top will be graded to reduce percolation into the WRSA and the plateau and benches will be covered with soil and revegetated. Most will be rehabilitated during operation. Only WRSA-D will still need to be rehabilitated at mine closure. All stockpiles will be inspected and further rehabilitation will be conducted as required. After the end of mining, WRSA water runoff and seepage will still be collected by the perimeter ditches and directed to Mosher Mine shaft, or later directed to the upper layer of the pit lake. Some contact water collection ponds may be fitted with a constructed wetland system if better water quality is required. Studies may be carried out during operation to test treatment efficiencies and better define these systems. If water quality from one of the contact water ponds consistently meets effluent criteria, with or without a constructed wetland, then pumping of water will end and the pond will be discharged through overland drainage to the environment. 10/16/

24 Concept for Reclamation of Waste Rock Storage Areas 10/16/

25 Final Closure and site reclamation: Overburden Storage Areas / Historic Tailings / Ore Stockpile At closure, stockpiled overburden will be used for rehabilitation across the site. For the historical MacLeod tailings, a minimum thickness of overburden will be maintained as final cover to reduce water infiltration into the tailings. The cover design will be evaluated to demonstrate that it will maintain performance objectives, but is currently assumed as a minimum thickness of one metre. Once the site is rehabilitated and there is no further need for overburden as cover material, the storage areas will be graded to stabilize slopes and then revegetated. After the entire ore stockpile has been processed, this area will be rehabilitated. The rock pad upon which the ore stockpile was situated is expected to be removed and placed into the open pit, or relocated to WRSA-D. Soils below the ore stockpile will be sampled and managed in accordance with the Soil Management Plan. The ground surface will be graded, amended with growth media as required, and revegetated. 10/16/

26 Final Closure and site reclamation: Historic Tailings The seepage collection system at the historical MacLeod mine tailings may be fitted with a constructed wetland to improve water quality. Pilot scale treatment studies during operation can evaluate the treatment efficiencies and better define how such systems may be used at closure. In closure and post-closure, water from the subsurface seepage collection system (or its constructed wetland) will be pumped to pond M1 from which it will be pumped to Mosher Shaft or to the pit lake. If water quality from either of the seepage collection ponds is found to consistently meet effluent criteria (with or without a constructed wetland), that water will be allowed to discharge overland to the environment (Barton Bay). Tailings along the lakeshore from both the MacLeod and Hardrock mines will permanently remain in their current location, to avoid disturbing the naturalized vegetation along the lake. 10/16/

27 Post-Closure Monitoring Programs

28 Post-Closure monitoring: Tailings Management Facility The TMF will be monitored monthly when pumping from the TMF to the open pit, including inspections of the reclaimed surface cover, water level and pond slopes, spillways, tailings dams, and seepage collection system. Dam Safety Inspections and Reviews for the TMF in accordance with the national guidelines and the Ontario Lakes and Rivers Improvement Act. GGM expects that dam safety inspections will be done annually and reviews every five years, which will support formal dam safety reviews and geotechnical risk assessments. 10/16/

29 Post-Closure monitoring: Overburden and Waste Rock Storage areas Overburden stockpile Waste Rock Storage Regulations require the WRSAs to be monitored for signs of physical instability (slope stability, erosion and vegetation) each month during initial rehabilitation, decreasing to annually as closure progresses. Inspections will be completed annually during active rehabilitation and reduced to every five years until stable conditions have been confirmed. 10/16/

30 Post-Closure monitoring: Water and Aquatic Biology Monitoring of water quality will include on-site ponds and discharges, as well as creek and lake water chemistry. Biological monitoring of fish, aquatic insects, etc. in creeks and lakes will follow requirements set in permits and regulations. As water quality improves in on-site ponds, with or without constructed wetlands, they may be allowed to discharge directly to the environment. There will be an extensive groundwater program (levels and chemistry) 10/16/

31 Final Site Conditions following closure

32 Final Site Conditions Land uses anticipated: Rehabilitation is focused on promoting vegetation communities that support local habitat for local species diversity. Anticipate that recreational activities such as hunting, hiking, snowmobiling and economic uses such as forestry will occur. Access roads to Kenogamisis Lake: Continued use of proposed new East Access Road to the main basin and SW Arm. Possible re-opening of Lahtis Road. Areas of limited usage for safety, and to protect vegetation: Tailings Management Facility Remaining historic tailings Pit lake Possible long-term operation of the power plant by others is not part of the present Closure Plan. 10/16/

33 Questions and discussion Thank You