Multiple Modeling Approach for the Aquatic Effects Assessment of a Proposed Northern Diamond Mine Development

Abstract

Eight water models were used to assess potential aquatic environmental effects of the proposed Gahcho Kué diamond mine on groundwater and surface water flow and quality in the Northwest Territories, Canada. This sequence of models was required to cover different spatial and temporal domains, as well as specific physico-chemical processes that could not be simulated by a single model. Where their domains overlapped, the models were interlinked. Feedback mechanisms amongst models were addressed through iterative simulations of linked models. The models were used to test and refine mitigation plans, and in the development of aquatic component monitoring programs. Key findings generated by each model are presented here as testable hypotheses that can be evaluated after the mine is operational. This paper therefore offers a record of assumptions and predictions that can be used as a basis for post-validation.

Development and Application of a New Exponential Model for Hydraulic Conductivity with Depth of Rock Mass

“…Other datasets with small amounts of data originate from many studies [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53], including igneous rocks, metamorphic rocks, and sedimentary rocks. These datasets are mainly located in Asia and Europe.…”

“…Winkler [50]; Zhao [47]; Achtziger [26,53] 2. Non-Faulted A complete rock mass that has not been crossed by a fault, located in Europe, Asia, North America Z (0, 1400 m) Macdonald [51]; Vandenberg [52]; Achtziger [26] The geological strata in the engineering project area are discontinuous and missing, and the spatial distribution of each layer is clearly controlled by the regional geological structure. The main strata are as follows: Paleoproterozoic (Pt1), Changcheng (Ch), Ordovician (O), Carboniferous (C), Triassic (T), Jurassic (J), Cretaceous (K), Paleogene (E), Neogene (N), and Quaternary (Q).…”

The future direction of pit lakes: part 1, Research needs

“…As an example, the use of pit lakes for sub-aqueous mine waste disposal (discussed in Part 2; Vandenberg et al 2022) may present risks to downgradient aquifers without a better understanding of the interaction between disposed waste, its pore water, and groundwater discharge as a function of pit lake elevation. In some cases, study methods are already available (Lewandowski et al 2015;Rosenberry et al 2015;Vandenberg et al 2016). Detailed field investigations need to be conducted, and hydrogeological and limnological studies should be coupled to better estimate the effect of hydrogeology on lake physics, mixing and water quality.…”

“…Modern limnological pit lake predictions incorporate hydrodynamic models prior to geochemical modelling to explore the depth of mixing and stratification on a seasonal basis (Oldham et al 2009;Vandenberg et al 2016). Such models consider the density of inflowing fluids, the geometry of the pit, and daily wind speeds and temperatures, which can all lead to stratification or mixing (Salmon et al 2017).…”