Abstract
The International Network for Acid Prevention (INAP) has been working towards improving mine rock placement strategies to reduce water quality risks during operations through into closure for mine rock stockpiles (MRS). The final report from Phase I of INAP’s improving MRS rock placement strategies was published in January 2020[1]. Since publishing this report, Okane has advanced the development of these concepts through evaluating the question “What value does constructing an MRS with a focus on source control provide in respect of reducing asset liability to an acceptable level of residual risk?”.
A key component of the recent work is development of a decision-making framework to inform on the benefits of including methods to enable source control measures within the mine rock stockpile during construction. The tool outlines how the level of uncertainty can be managed through different mitigations and controls to ultimately reduce the probability of unrecognized and underfunded liability for sites through operations and closure. Similar to the INAP Global Cover System Design Technical Guidance Document[2], this tool is a means of facilitating early conceptualization to form realistic expectations around if the standard mine rock stockpile construction practice will achieve the desired or required closure outcomes. This paper will present the progress of the INAP MRS Source Control project including an overview of the development of the proposed decision framework, and a comparative analysis demonstrating through case studies the challenges and opportunities between construction of a conventional MRS and one with a source control methodology.