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MDAG.COM
MINES, MINING, AND THE ENVIRONMENT







MDAG.com: Since 1997, Providing Valuable Technical Information on Minesite-Drainage Chemistry and Environmental Geochemistry through the Internet

 

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For proposed minesites, predictions of drainage chemistry typically address the anticipated average-annual concentrations, with little consideration of shorter-term variability. Also, monitoring programs for existing and closed minesites often involve sampling periods such as monthly or quarterly. These relatively long-term events ignore the known dynamic nature of minesite-drainage chemistry over shorter periods, like days and hours. Also, regulatory permits often regulate minesite concentrations based on single, near-instantaneous (e.g., one minute) "grab" samples, and chronic and acute toxicity to aquatic ecosystems can occur over short periods like hours and days.

Therefore, there is a strong need to improve predictions of short-term concentrations for proposed minesites. There is also a strong need for existing and closed minesites to understand and anticipate their short-term maximum concentrations that may not be detected often, or at all, by their monitoring programs. Databases of orderly (non-chaotic) long-term and high-frequency, full-scale minesite-drainage chemistries are evaluated here using two mathematical approaches, fractals and lognormal statistcs, to determine how and how well short-term maximum concentrations could be estimated. The data and findings are provided in the latest MDAG Case Study #40, entitled "Fractal and Lognormal Characteristics, Short-Term Maximum Concentrations, and Appropriate Time Discretization of Minesite-Drainage Chemistry".

Interestingly, the short-term maximum concentrations can be estimated without addressing underlying mechanisms, such as sulphide oxidation and metal-leaching rates. This is attributable to the emergence of dominant processes at the full scale of minesite components that are minor at smaller scales.


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What is nonlinear science? As one researcher explained, "When asked this question at a cocktail party, I often paraphrase Aristotle, saying that nonlinear science is the study of those dynamic phenomena for which the whole differs from the sum of its parts...". There is no doubt that minesite-drainage chemistry is full of nonlinearity. Case Study 41 (Nonlinear Science of Minesite-Drainage Chemistry. 1 - Scaling and Buffering) discusses the first two examples: scaling and buffering.

Nonlinear aspects of scaling are attributable to exceeding the scale transition at relatively small scales and the concomitant change from kinetic (more-or-less linear) or equilibrium (non-linear with scale) conditions. Nonlinear aspects of buffering are attributable to aqueous and solid-liquid interactions that restrict pH and pH-dependent aqueous concentrations to narrow ranges in a stepwise manner.


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We have had the opportunity to collaborate recently with Dr. Getnet Betrie.  He has applied machine-learning and uncertainty-quantification techniques to minesite-drainage chemistry, discovering interesting results.  The published papers are listed here, including two recent papers on ARD risk assessment under uncertainty.


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Interested in minesite-drainage chemistry, but not sure where to start? Looking for a basic introduction with dozens of colour photographs from minesites around the world?

MDAG Publishing has released an ebook by Dr. Kevin Morin, entitled Minesite Drainage Chemistry: An Introduction. This printable ebook in PDF format can be read on many ebook readers, laptops, and desktops. It costs CAD$5.00, can be downloaded immediately after online payment, and contains no digital-rights management or security limitations.

Click here, and then click the first link for the ebook.

We have also published many papers at conferences and journals, as well as Internet case studies and another book here at MDAG.com.
 


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We steadfastly believe that the environmental effects of drainage chemistry can only be understood, predicted, and moderated by thoroughly understanding past competent work and by carefully studying existing operations and sites. Heed the old words of wisdom: "Those who ignore the past are doomed to repeat it". Is that why we hear that up to 90% of predictions of minesite-drainage chemistry are too low, leading to unexpected costs and environmental effects for mining companies?  This is why we heavily emphasize real case studies with abundant data, followed by theory and modelling in subordinate roles.

 

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