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.
