EXECUTIVE SUMMARY

Minesites can consist of many components including the mine itself (pits and underground workings), tailings impoundments, waste-rock dumps, ore stockpiles, plantsites, building foundations, and roads. Any component can affect the chemistry of water flowing over, or through, it by various geochemical processes. These processes include the leaching of metals and nonmetals at neutral, acidic, and alkaline pH and the oxidation of sulfide minerals.

Case studies of water chemistry and geochemical processes in tailings impoundments are generally available (e.g., Jambor and Blowes, 1994). Similar studies for mine-rock piles including roads and foundations are less common, but still available (e.g., Morin et al., 1991). However, geochemical investigations of pits and underground workings ("mines") are rarer.

In order to better understand and predict water chemistry in and around mines in Canada, the Canadian Mine Environment Neutral Drainage (MEND) Program and the British Columbia Acid Mine Drainage Task Force sponsored a project now known as MINEWALL 1.0 (Morin, 1990). That study involved (1) a literature review, (2) a one-time geochemical assessment of the Main Zone Pit at Equity Silver Mines (British Columbia), (3) the development of a rudimentary site-specific computer program for predicting pit-water chemistry (MINEWALL 1.0), and (4) recommendations for conducting pit-water assessments.

MEND and the Task Force decided to expand and refine MINEWALL, leading to MINEWALL Version 2.0. This is one of four reports describing MINEWALL 2.0, which is both a simple technique for predicting water chemistry in mines and a computer program to assist with predictions for complex scenarios. MINEWALL 2.0 is based on literature reviews of relevant theory, testwork, and past studies, some over 30 years old (summarized in Morth et al., 1972). As a result, the technique and program were designed to be flexible and widely adaptable to many site-specific conditions.

The following sections of this report present the results of simulating three mines with MINEWALL 2.0. Because MINEWALL is a relatively new technique, not all required information was available for the simulations (Appendix A), but company reports have provided much of the input data. Other input values were estimated or obtained by fitting monitoring data to simulations of current conditions. As a result, this report also illustrates the importance of various input data and the strengths and weaknesses of the MINEWALL 2.0 computer program.

In addition to this Application report, there are three other related reports. The first is a User's Manual for the computer program. This Application supplements that document by illustrating the use of the program and input data. However, this report is not a substitute for the User's Manual and the reader should be familiar with it before proceeding.

The second related report is the Programmer's Notes and Source Code. That document discusses some of the more technical aspects of MINEWALL's programming and contains a listing of MINEWALL 2.0's roughly 24,000 lines of code. The third related report is the Literature Review and Conceptual Models which presents the conceptual models and case studies on which the design of MINEWALL 2.0 was based.

Last Modified: 2003-11-26		Important Notices

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