Dewatering: Thickening, Filtering, CCD, Water Treatment & Tailings Disposal

Dewatering: Thickening, Filtering, CCD, Water Treatment & Tailings Disposal 2017-04-04T06:57:46+00:00
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ARD Acid Rock Drainage Case Studies (13 replies)

Standartenfurer
2 years ago
Standartenfurer 2 years ago

What is the track record of modern copper mines for ARD in North America? Are modern U.S. and Canadian porphyry copper mines protecting water quality?

I'd like a good critique if this Earworks paper:http://www.earthworksaction.org/files/publications/Porphyry_Copper_Mines_Track_Record_-_8-2012.pdf

It suggests modern copper mines have significantly degraded surface/ground waters despite NEPA and modern management systems due to pipeline, treatment, and tailings failures. I'd like to better understand water quality risks at the proposed Pebble mine in southwest Alaska and how to mitigate and/ml in a high rainfall, sub-arctic climate.

Victor Bergman
2 years ago
Victor Bergman 2 years ago

The Kemess Mine in the Northern Interior of British Columbia provides an excellent example of proper waste management to prevent the generation of ARD. The mine experienced a minor problem with selenium leaching, but this was found to be ecologically inconsequential.

Two papers that describe the reclamation program include:

http://www.trcr.bc.ca/wp-content/uploads/2012/11/Kemess-South-Mine-Reclamation-and-Closure.pdf

https://circle.ubc.ca/bitstream/handle/2429/24643/15McConnachie.pdf?sequence=1

Carmen Ibanz
2 years ago
Carmen Ibanz 2 years ago

I am sure you are quite capable of conducting your own analysis of the environmental compliance status of porphyry coppers. In North America, the compliance results (along with the EIS/EIA documents compiled prior to mining) are all part of the public record, so you don’t have to rely on anyone's analysis or opinions.

No one proposes to mine porphyry copper without engineering controls, so the underlying, unmitigated hazards of porphyry are not the risks. What is needed is an analysis of the specific porphyry copper mining plan that is being proposed, including an engineering reliability analysis for the components that affect environmental performance. The issue in looking at a new mine application is whether the plan being proposed

  • adequately mitigates the risks
  • Is believably capable of being implemented at this site by this operator.

Can the Proponent (or the regulators) guarantee that there will be no failures of equipment or operators during a 25-100 year life of the mine? Of course not, no more than I and the State of California can guarantee when I am issued a driver’s license that, during the next 10 years, I will not have an accident.

The history of prior mining of the same kind is a legitimate matter of inquiry, as it illuminates the sorts of failure modes and effects that need to be considered with respect to the proposal that is now to be considered. But my experience with porphyries is that cosmic generalizations are not very helpful. NEPA does not require that there be no impacts, only that the impacts be identified and assessed, that there be plans for mitigation of the risks of adverse impacts, and that the balance of the evaluation of cost and benefits has been properly and publically evaluated in advance of decision-making.

OberstGruppen
2 years ago
OberstGruppen 2 years ago

I beg to differ with your comments. Any company can say what they want in an EIA/EIS and yes most I have seen in Canada would meet the criteria suggests. Although there are several in British Columbia that have recently failed the EIA/EIS approval process. Having said, that most mines are not built nor operate exactly as described in an Application, Changes in ownership, management, design lead to changes in what is built. Secondly, not all mines are operated well, which can lead to non-compliance issues and problems.

In my opinion we do need more case studies of "before and after", particularly on water quality modeling. The bottom line is a good operator will be proactive with on-going research and adaptive management that seeks to strive for the goal of "design for closure" (remember the first ICARD Symposium in the 90's?) and achieve a reduction in liability and risk from the EA stage right through construction, operations and closure. Over that long timeframe there are a lot of different people involved and unless a company is well management, those engineering controls will not ALWAYS function as intended.

In fact this case presents is an interesting one where the previous operations are closed and a great success story only because of a change in ownership and management. However, there recent attempt at approval to develop an adjacent deposit failed to pass the EA process, which is now undergoing a major engineering design change.

Carmen Ibanz
2 years ago
Carmen Ibanz 2 years ago

Don't actually think we disagree on anything. If there are operations that are not proactive and don't follow through on their plans and fail to operate well, then their consultants should be urging action, up the management line, if necessary. Independently, regulators should take action. Of course this is true for porphyry coppers, but also for sand-and-gravel operators, forest products operators, and petrochemical plants.

That EA/EIA processes lead to rejections can be read as demonstration that the environmental approvals process is capable of being applied in the public interest. We need to participate in the process - representing proponents, regulators, NGOs, First Nations, as the case may be - in the spirit of fulfilling our obligations as qualified persons. And we need to ensure that programs are in place throughout the life cycle of the mine to ensure that operations and closure proceed and that necessary and sufficient monitoring programs and decision-making driven by good science will be carried out.

Requiring a guarantee that there will be no management failures or accidents in the future is an impossible condition, whether the case at point is a porphyry copper or any other industrial process.

Standartenfurer
2 years ago
Standartenfurer 2 years ago

Thank you for the comments!

Do you know of any other review of the compliance of copper mining in North America? I don't know how I would make such an analysis, as regulations are site-specific and I assume there are so many "behind-the-scene" changes to the mine plan, operations, management, etc that blur judgment of what constitutes poor, satisfactory, good, and best practice.

How would you judge current water quality modeling practices? Do you know of published case studies before/after as you recommend?

Bill Rico
2 years ago
Bill Rico 2 years ago

For what it’s worth, you can check out “Comparison of Predicted and Actual Water Quality at Hardrock Mines, the reliability of predictions in Environmental Impact Statements” by Kuipers and Maest. I think our industry is moving toward stochastic based forward simulations (predictions). And I agree with comments above that we need to be more committed to completing periodic post-audit evaluations.

Carmen Ibanz
2 years ago
Carmen Ibanz 2 years ago

You provided the only other review of which I know, also prepared in association with EarthWorks. Note that the first author of the one you cites is the same as the first author for the porphyry-copper study.

My advice on evaluating compliance is that you formulate a hypothesis, e.g. "Mining in North America from porphyry copper deposits has an improving record for water-quality compliance during operations since 1980," (or its negation, if you prefer). Then work out how you would test the hypothesis. This does not at all require that you accept anyone's current idea of what constitutes "best practice." It does not even require you to understand the details of any mine are planning and operational details. At a first pass, either the mine meets its discharge permit requirements, or it does not. The scale of compliance exceptions (number of exceedances scale of exceedcances, longevity of exceedances) could be evaluated. I think you will find Mr. Kuiper's methodology set out in his two reports. I am sure that youwould be happy to discuss methodologically issues and sources of information with you.

I agree that if you tried to do this for every copper deposit in the world, or even every porphyry copper, it would be a complicated matter. So as a practical matter, set up the problem for a specific jurisdiction, and for you it would make sense for that to be BC. To improve the statistical power of your analysis, I suggest you include porphyry molybdenum deposits together with porphyry coppers; the two styles have a great deal geochemically in common. Then, if you wish to expand your analysis to a more generalized form, take your BC study as the set of prior probabilities, and add a new jurisdiction, say Arizona, and analyze the problem in a Bayesian manner.

Re: Water-Quality modeling

The paper you cites on case studies had a companion paper, Predicting Water Quality at Hardrock Mines (Maest et al, 2005). There also is discussion of modeling and its issues in the GARD Guide and also in the ADTI workbook series published by SME.

There also are some very important papers that should, imo, be part of every modeler's background. A central one is Oreskes, N, Shrader-Frechette,N and Lelitz, N., 1994. Verification, validation, and confirmation of numerical models in t he Earth sciences. Science, v. 263, p 641-646. An essential report for geochemical modeling of natural waters is Alpers, C.N. and Nordstrom, DK, 1999. Geochemical Modeling of Water-Rock Interactions in Mining Environments, p 289-323, in Plumlee and Logsdon (Eds). The Environmental Geochemistry of Mineral Deposits, Society of Economic Geologists, Reviews in Economic Geology Vol 6A. For more advanced applications that are suitable to mine-waste issues, it is well to read Mayer, U., Blowes, DB and Frind, EO, 2003, Advances in Reactive Transport Modeling of Contaminant Release and Attenuation from Mine-Waste Deposits, in Jambor, Blowes and Ritchie (Eds), Environmental Aspects of Mine Wastes, Mineralogical Association of Canada, Short Course Volume 31, p. 283-302

Finally, There remain some very important issues about applications of stochastic modeling to these problems. For one perspective, see JI Drever’s editorial, “Prediction is Hard – Particularly about the Future,” in Elements, Vol. 7 No 6 (Dec 2012). I think the comments are probably particularly relevant to people working on the scientific end of policy questions, such as how geochemical analyses and prediction should be used in environmental decision-making.

Standartenfurer
2 years ago
Standartenfurer 2 years ago

Thank you very much for your comments. I have read both the Kuipers and Maest papers several years ago, but I obviously need to re-read them. I wanted to be sure that professionals in the field have seen them and acknowledge the results, because they are produced by an organization with an obvious ideology in the background.

Well I am now currently completing an internship in Chile, so I will change tack and analyze mine waste compliance and management strategy here, followed up later by a comparison to SW USA and BC later. Climate and meteorology have no resemblance but it will still be a good practice I think. Thank you for the recommended reading!

Carmen Ibanz
2 years ago
Carmen Ibanz 2 years ago

It is important to understand that the 2005 Maest and Kuipers papers were NOT produced by EarthWorks. The program of work that led to the papers was developed and partially funded in cooperation with EarthWorks, but they retained full editorial control, and they used independent reviewers. EarthWorks felt it necessary to prepare a separate "white paper" that took a specific viewpoint toward the work reported in the Kuipers et al Comparisons report, but it is in no way a substitute for the original report itself. Not everyone agrees with everything in the Kuipers et al paper, but that does not mean that the issues raised are not taken seriously.

"Ideology" is a funny thing. In modern Western parlance it has come to be a term of opprobrium, usually something we impute to our "opponents", rather than to ourselves. In large part this is because we have come to act as if we thought that the world operates best when there is fierce competition, of the sort implied by "zealous advocacy." Too often "ideology" is a term - something like "common sense" - that is used to try to terminate debate, rather than to advance it. Here in the States one of our fundamental philosophical documents is Thomas Jefferson's preamble to the Virginia Statute for Religious Freedom: "[T]ruth is great and will prevail left to herself...she is the proper and sufficient antagonist to error, and has nothing to fear from the conflict, unless by human interposition disarmed of her natural weapons, free argument and debate, errors ceasing to be dangerous when it is permitted freely to contradict them."

Good luck with your research - we hope to see the results published one day soon.

Standartenfurer
2 years ago
Standartenfurer 2 years ago

Thank you for clarifying that.

I have used the definition of "ideology" from Thompson (1990): Ideology is meaning in the service of power. Yes, it is broad, maybe vague, and often abused to circumvent more difficult, complicated arguments. I got my degree in Sustainable Development, a 4yrs MA course, but after working in the minerals industry (gold exploration) for several years, I see environmental groups, ideas, and attitudes differently.

I support Earthwork's unstated mission of socially and environmentally responsible resource development, or sustainable mining, and some of their critiques have been constructive. But overall, the discourse in the media is like you describe: full of shouting, low punches, and unproductive. Alaskan's would be better off learning about difficult, complicated science and engineering of mining - but that would be boring!

Carmen Ibanz
2 years ago
Carmen Ibanz 2 years ago

Decision-making under uncertainty is always difficult, and there are real asymmetries of power in almost all environmental exercises. In the abstract, we'd like the general citizenry to be well informed and involved, but of course that is not really practicable, certainly not across the full range of public policy questions that affect the lives of ordinary citizens. That’s why, in a republic, the citizens delegate authority.

And so we institute procedures to moderate the uncertainties of decision-making. That is the function of NEPA (or was when it was developed). There probably are some pretty straightforward exercises: say an EA looking at putting a new cell-phone tower on a ridge line somewhere. But a system and process as complicated at Pebble? Goodness.

Line me up: the minimum requirement is procedural justice, which the process of NEPA - as unwieldy and complex as it is - is designed to provide. The issues will never be entirely scientific or resolvable by an obvious appeal to known engineering, but we are apt to make better decisions when there is a fair and open hearing of the scientific and engineering information. That's the beginning of the story, not the end, which requires follow-through by multiple parties. But how or even whether that follow-through will happen is not a matter on which the procedures of NEPA have much of anything to say. The best we can hope for, I think, is that there will be a clear public record that a fair evaluation (within the terms of NEPA) has been conducted, and then – having delegate dour authority initially, we have to step back and assert our responsibility (which is something we cannot delegate) to ensure that the terms and conditions are met and that those who undertake the work – proponents and regulators – execute their responsibilities in an accountable fashion.

Gruppen
2 years ago
Gruppen 2 years ago

Based on projects I have worked I would tend to think that since the mid-1980's the track record of copper companies in the US has been extremely good. I am not in agreement with the Earthworks paper which largely cites historical studies and does not address post impact mitigation that has occurred in many of the examples used. Improvement has been through enforced regulation changes initially but in the last 10 yrs especially I think US companies have gone to see environmental and social management as part of the bottom line assessment. Will be interesting to see if this correlates to copper price or not but I think at present the story is mostly a success and refutes some of the claims made in the cited papers.

Standartenfurer
2 years ago
Standartenfurer 2 years ago

The paper does use all post-NEPA mines but selection was purposeful, not random. I disagree with EPA's current pre-emptive veto action, but Pebble is a unique project in a unique place. Does it need different legislation to that provided by NEPA and the dozens of other local, state and federal laws?

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