Evaluating the impacts of mine dewatering and flooding on peatlands

采矿活动涉及减轻环境影响，对加拿大强劲的经济发展至关重要。然而，泥炭地退化和矿井脱水/洪水之间的联系还没有得到很好的了解。这种环境评估的差距可能导致重大的环境和财政影响。该方案针对预先确定的问题。长期总体目标是发展新的方法来评价矿井脱水/水淹对泥炭地的影响。具体目标是(1)评价泥炭地对矿山脱水的水文响应；(2)评价泥炭地对矿山脱水的地球化学响应；(3)模拟矿山脱水/淹水对泥炭地水文和化学平衡的影响。目标泥炭地位于Agnico-Eagle Akasaba-West矿区（Abitibi， QC）附近，露天开采预计将于2018/2019年开始。SO1 （MSc1）侧重于建立水预算。记录仪将安装在测压仪巢和acrotelm中，以监测饱和和不饱和泥炭的水位和温度。与泥炭地相连的河流的流量和温度波动也将受到监测。这些数据将使人们能够对基岩含水层上的泥炭地的水文反应进行前所未有的评价，因为基岩含水层正在因矿井脱水而降压。SO2 （MSc2）侧重于建立地球化学收支。在一年的时间里，我们将监测泥炭孔隙水（来自测压仪巢）和溪流样本的地球化学。现场物理化学参数（包括Eh和pH）也将被监测。分析项目将重点评估三种主要氧化还原和pH敏感元素（Mn, Fe, As）的浓度和形态，以及它们与水的稳定同位素（2H, 17O, 18O）和溶解有机碳含量变化的联系。地球化学和水文数据将联合解释，以评价受矿井脱水影响地区泥炭地水文与地球化学平衡之间的联系。SO3 （PhD1）侧重于建模。采用SEEP/W进行瞬态水文模拟。将使用PHREEQC和地球化学工作台评估As的形态。将使用CTRAN/W模拟As的传输。模拟将按照系统参数方法进行，以测试矿井脱水/淹水对泥炭地的各种情况的影响。该项目将提供新的数据，以了解泥炭地对采矿的敏感性。这种方法将物理、化学和同位素数据与建模相结合，是一种新颖的方法，与采矿业和科学界高度相关。目标矿区预计将于2018/2019年开始运营：这是一个同步启动该计划的独特机会。

Mining activities, which involve the mitigation of environmental impacts, are essential to the strong economic development of Canada. Nevertheless, the links between peatland degradation and mine dewatering/flooding are not well understood. This gap in environmental assessments can lead to major environmental and financial impacts. This program targets the pre-established issue. The long-term general objective is to develop novel approaches for evaluating the impacts of mine dewatering/flooding on peatlands. The specific objectives (SO) are (1) to assess the hydrological response of a peatland to mine dewatering, (2) to evaluate the geochemical response of a peatland to mine dewatering and (3) to simulate mine dewatering/flooding impacts on peatland hydrological and chemical balance. The targeted peatland is located near the Agnico-Eagle Akasaba-West site (Abitibi, QC), where open-pit mining is expected to begin in 2018/2019. SO1 (MSc1) focuses on establishing a water budget. Loggers will be installed in piezometer nests and in the acrotelm for monitoring water levels and temperature within the saturated and unsaturated peat. Discharge and temperature fluctuations in the stream connected to the peatland will also be monitored. The data will allow an unprecedented evaluation of the hydrological response of a peatland overlying a bedrock aquifer undergoing depressurization owing to mine dewatering. SO2 (MSc2) focuses on establishing a geochemical budget. The geochemistry of peat pore water (from piezometer nests) and stream samples will be monitored during one year. In situ physicochemical parameters (including Eh and pH) will also be monitored. The analytical program will focus on the evaluation of the concentration and speciation of three main redox and pH sensitive elements (Mn, Fe, As) and on their links with variations in the stable isotopes of water (2H, 17O, 18O) and in dissolved organic carbon contents. The geochemical and hydrological data will be interpreted jointly to evaluate the linkages between peatland hydrological and geochemical balance in an area affected by mine dewatering. SO3 (PhD1) focuses on modeling. Transient hydrological simulations will be carried out using SEEP/W. The speciation of As will be evaluated using PHREEQC and Geochemist's Workbench. The transport of As will be simulated using CTRAN/W. Simulations will be conducted following a systematic parametric approach for testing the impacts of various scenarios of mine dewatering/flooding on the peatland. The program will provide novel data needed to understand the sensitivity of peatlands to mining. The approach, coupling physical, chemical and isotopic data with modeling, is original and highly relevant for the mining industry and the scientific community. The targeted mining site is expected to start operating in 2018/2019: there is a unique opportunity to initiate the program synchronously.