Environmental Impact Assessment Mine Decommissioning Penobsquis Potash Deposit
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ENVIRONMENTAL IMPACT ASSESSMENT MINE DECOMMISSIONING PENOBSQUIS POTASH DEPOSIT Submitted to: Potash Corporation of Saskatchewan Incorporated (PotashCorp) NB Division Penobsquis, New Brunswick Submitted by: Amec Foster Wheeler Environment & Infrastructure, a Division of Amec Foster Wheeler Americas Limited Fredericton, New Brunswick April 2016 TE154017.4000 PotashCorp Environmental Impact Assessment Decommissioning of Potash Mine – Penobsquis Deposit Penobsquis, New Brunswick April 2016 EXECUTIVE SUMMARY In late October 2012, Potash Corporation of Saskatchewan Inc. - New Brunswick (NB) Division (PotashCorp) began mining the Picadilly deposit, located approximately 400 metres (m) south of the original Penobsquis mine, and jointly operated both mines for approximately 12 months. In November 2015, mining operations permanently ceased at the Penobsquis mine and plans to decommission the site were formulated. Although decommissioning of the Penobsquis site will include removal of the site service shaft and production shaft head frames, as well as other surface infrastructure, the primary components of the decommissioning will involve the underground mine facilities (the Project). Considering that in the near future there will not be any reason to access the underground mine workings at Penobsquis, it is proposed that the management of the underground inflow be stopped, the mine be allowed to flood naturally and the shafts be capped or plugged. Shaft capping/plugging options are currently under review and final design will be reviewed and approved through New Brunswick Department of Energy and Mines (NBDEM). The Project is considered an undertaking subject to approval under the Environmental Impact Assessment (EIA) Regulation of the New Brunswick Clean Environment Act. The Project activities are also subject to stipulations under the New Brunswick Mining Act. PotashCorp has retained the services of Amec Foster Wheeler Environment & Infrastructure, a Division of Amec Foster Wheeler Americas Limited (Amec Foster Wheeler) to prepare this EIA report in support of the registration of the Project under the provincial EIA process. A description of both the surface and subsurface environments within which the Project activities will occur, or potentially have an influence on, was developed from existing information. Potential positive and negative interactions between Project activities and the environment were identified. Where negative interactions were anticipated, and potential effects were a concern, methods for mitigating and/or monitoring the effects have been proposed. A description of the existing environment in the Study Area as well as the Subsurface Study Area (SSA) has been presented (see Section 4.0) based on available information. The Valued Environmental Components (VECs) identified by issue scoping and pathway analysis (see Section 5.0) for which potential effects may be a concern included: ambient air quality; physiography and drainage; surface water; groundwater; mineral resources; species at risk, migratory birds and wildlife; migratory birds; fish, fish habitat and fisheries resources; labour, industry and commerce; existing land use; and TE154017_PotashCorp_Decomm_EIA_29Apr2016.docx TE154017.4000 www.amecfw.com Page i PotashCorp Environmental Impact Assessment Decommissioning of Potash Mine – Penobsquis Deposit Penobsquis, New Brunswick April 2016 heritage and archaeological resources. This report also identifies measures intended to mitigate potential environmental concerns, and provided a discussion of potential residual effects resulting from the proposed Project. As the Project progresses discussion surrounding monitoring and mitigation will continue. Based on this Study, given the proposed mitigation and monitoring, no significant adverse residual effects are anticipated as a result of the Project. TE154017_PotashCorp_Decomm_EIA_29Apr2016.docx TE154017.4000 www.amecfw.com Page ii PotashCorp Environmental Impact Assessment Decommissioning of Potash Mine – Penobsquis Deposit Penobsquis, New Brunswick April 2016 TABLE OF CONTENTS PAGE 1.0 INTRODUCTION .................................................................................................................. 1 1.1 BACKGROUND ........................................................................................................... 1 1.2 PROJECT RATIONALE .............................................................................................. 5 1.3 REGULATORY FRAMEWORK ................................................................................... 5 1.4 REPORT ORGANIZATION ......................................................................................... 5 2.0 PROJECT DESCRIPTION ................................................................................................... 8 2.1 UNDERGROUND MINE WORKING ACTIVITIES ....................................................... 8 2.1.1 End of Potash and Salt Extraction ................................................................... 8 2.1.2 Underground Equipment Inventory .................................................................. 8 2.1.3 Grouting ........................................................................................................... 8 2.1.4 Mine Flooding and Cessation of Brine Management ....................................... 9 2.1.5 Shaft Plugging and Capping ............................................................................ 9 2.2 DECONSTRUCTION OF NON-ESSENTIAL SURFACE INFRASTRUCTURE .......... 9 2.2.1 Utilities ............................................................................................................. 9 2.2.2 Shaft and Headframe Deconstruction ............................................................ 10 2.2.3 Demolition of Offices and Storage Buildings ................................................. 11 2.3 DECOMMISSIONING MILESTONES ....................................................................... 11 3.0 APPROACH AND METHODOLOGY ................................................................................ 12 3.1 ASSEMBLING PROJECT BASELINE INFORMATION ............................................. 13 3.2 ISSUES SCOPING .................................................................................................... 13 3.3 APPROACH TO THE SELECTION OF VECS .......................................................... 13 3.3.1 Identification of VECs .................................................................................... 13 3.3.2 Approach to Bounding ................................................................................... 13 3.4 APPROACH TO DETERMINATION OF SIGNIFICANCE ......................................... 14 4.0 ENVIRONMENTAL AND SOCIO-ECONOMIC SETTING ................................................. 15 4.1 STUDY AREA DEFINITION ...................................................................................... 15 4.2 ATMOSPHERIC ENVIRONMENT ............................................................................. 17 4.2.1 Air Quality Regulations .................................................................................. 17 4.2.2 Climatology .................................................................................................... 20 4.3 PHYSIOGRAPHY AND DRAINAGE ......................................................................... 21 4.3.1 Surficial and Bedrock Geology ...................................................................... 22 4.3.2 Stratigraphy and Location of Mine Workings ................................................. 22 4.3.3 Potential for Seismic Activity .......................................................................... 24 4.3.4 Mineral Occurrences, Mining Claims, and Aggregate Resources ................. 24 4.4 HYDROLOGY (SURFACE WATER) ......................................................................... 24 4.4.1 Surface Water Quantity ................................................................................. 24 4.4.2 Surface Water Quality .................................................................................... 26 4.4.3 Watercourses ................................................................................................. 26 TE154017_PotashCorp_Decomm_EIA_29Apr2016.docx TE154017.4000 www.amecfw.com Page iii PotashCorp Environmental Impact Assessment Decommissioning of Potash Mine – Penobsquis Deposit Penobsquis, New Brunswick April 2016 4.5 HYDROGEOLOGY (GROUNDWATER) ................................................................... 26 4.5.1 Groundwater Quantity .................................................................................... 26 4.5.2 Groundwater Quality ...................................................................................... 27 4.5.2.1 Previous Domestic Water Well Surveys.......................................... 30 4.5.3 Wetland Resources ....................................................................................... 30 4.6 BIOLOGICAL ENVIRONMENT (FLORA AND FAUNA) ............................................ 30 4.7 SPECIES AT RISK .................................................................................................... 32 4.7.1 Plant Species at Risk ..................................................................................... 33 4.7.2 Mammal Species at Risk ............................................................................... 33 4.7.3 Bird Species at Risk ......................................................................................