That would be nice! It would be helpful to have a tool to create box plots of parameters/metals by rock type, alteration, etc.

I have posted some of my output files for some sample data here: http://packertest.com/ABADASS/Dashboard.html

Take a look and comment on what you like and don't like. I would like to make a comprehensive tool that people will get the most out of. With your help, I can make it the best it can be.

Great acronym! It might be nice to have the labels for the fields of classification on the plots as well i.e. uncertain/non-acid forming etc.

Cool stuff. I would suggest adding TC and TIC versus NP, and NPR based on the various sulphide sulphurs (Extractable, Difference) for deposits that only contain gypsum/anhydrite.

Thanks for the feedback so far. Some of those additions are pretty easy to make. I'm working on a "selection" feature that will allow a user to click on points of interest on the AGN/ANP chart and have the same points highlight on the other charts to make it easier to select HCTs. This is taking me a while to figure out the code, but I'm getting closer.

I'm also planning on adding features in the Excel file to change the aesthetics of the charts for some real customization like turning on/off grid lines, reference lines and custom scaling. I'll continue to update when I add new features.

One problem I've encountered is that every lab delivers data in different formats so I have an Excel spreadsheet "translator" for each lab I deal with. Many of my clients prefer specific labs so my data comes back to me in many different ways. The lab community should get together to unify the way they report results to make it less likely for propagation of errors. I'm happy to provide a lab an Excel template that will do the proper translation so let me know if you'd like me to do that.

Reconciliation of the mineralogy with the method results would be a useful tool to help with selecting the appropriate static testing methods to use for an ore deposit.

I posted some updated results.http://packertest.com/ABADASS/Dashboard.html . Pay close attention to the "HCT selector" page. This is under the "Standard Charts" menu heading. In this tab, you can select multiple samples on the AGP/ANP chart and the other charts populate to show the related samples. This page is designed to more easily select Humidity Cell Tests (HCT) from ABA data.

Updated functionality. The "HCT Selector" is close to being done. Can I please get some feedback on this? Eventually, I will be posting the finished Excel spreadsheet for public use. I would like to get more feedback on it prior to that point.

What are the objectives of the humidity cell tests selected in this way and how do you define the duration?

Good question. The HCT selector is used to select which samples are suitable to best represent the data for dynamic testing. By visualizing samples in all of the charts I've shown, you can see the behaviour of the rocks and alterations and where there are clumps of samples. Think of the data in these charts as a statistical distribution with some bimodal nature. Because different alteration types and rock types may behave differently, these discrete areas may form on the plots. Representing these 'clumps' is important as well as the 'highs' and 'lows' of the data. Typically, budget on a project plays a role in how many HCTs you can select and run, so choosing the 'best' representation of the data with as 'few' HCTs as possible. If you examine a mining project by tonnage, you can follow some 'unofficial' guidelines on how many per mass of waste. I typically like to take about 1 HCT per 10-15 ABA samples but there are no hard and fast rules.

As for running the HCTs, I'm developing some tools that will help make determinations on when they should end. At a MINIMUM, they should run for 20 weeks. Many cells will show stable conditions by this point, but some samples may take much longer to 'break through' the carbonate buffering. Another good test to do to predict the time of a HCT going acid is the Kinetic NAG pH test. With several kinetic NAG pH tests and HCT tests as part of your data suite, you can make good judgement calls on predicting when waste might go acid. It can be a big mistake to cut HCTs off too early, so unless it's a slam dunk that there is plenty of neutralization capacity after 20 weeks, run the cells longer. Acid isn't your only enemy... metals can leach out and those are important to quantify in your analysis.

Hope that answers your question. Let me know if I can help further.

It came to my attention that my linkhttp://packertest.com/ABADASS/Dashboard.html does NOT work in FireFox web browser. I'm working on a solution for this. In the meantime, please use Chrome or Internet explorer to view the content. I have fixed the issue. It should work in any browser now. Keep in mind this is a work in progress. Please let me know of any issues you may find!

https://packertest.com/ABADASS/Dashboard.html . New link that fixes some compatibility issues.

I have just completed the 5th Volume in the Acid Drainage Technology Initiative/Society for Mining, Metallurgy and Exploration (ADTI/SME) series: Techniques for Predicting Metal Mining Influenced Water. The volume is currently at the printer.

In this volume we have an extensive discussion of humidity cells which highlights the importance of a detailed understanding of geology including lithology, mineralogy and alteration history to interpret both static and kinetic acid drainage test results.

We discuss how the 20 weeks HC run time came to be the default duration and explicitly note it is not possible to establish specific test duration prior to test initiation.

We note the following for test duration: Ultimately, test duration must be a function of reducing outcome uncertainty and level of risk through the development of detailed objectives. It is these detailed objectives that should determine the duration, not a predetermined amount of time.

The volume also proposes flexibility for kinetic test duration through the development of a site-specific objective-based framework that can be developed and modified through stakeholder input.

There was also a session at the SME this year that included 6 presentations on humidity cells. From the abstracts it looks like there were some good presentations on the range of issues that humidity cells always bring up.

A fruitful area for continued discussions...

Thanks for your expertise in this area and the clarification on the 20 weeks reference. I'd like to read your papers on where that duration came about.

You are right about the project goals being the driver in humidity cells. When I evaluate samples for humidity cells from ABA I have thin sections and XRD done to better understand and predict the behaviour. There is no strict answer on humidity cell duration and every site will vary.

As far as the kinetic NAG tests, what is your take on these? From what I've read and in my experience they can be good proxies for when and if a HTC may go acidic.

Being the developer of the NAG and Kinetic NAG tests I thought I should provide some input on this. We use the KNAG test routinely and have a large data base of column leach test results. There are some mineralogies (as well as some process tailings) where the correlation between time to acidify in the KNAG and columns is poor, but overall the KNAG pH profiles provide a qualitative estimate of the lag time observed in columns. We have had confirmed lag times up to about a 10 years, and have columns running that we expect to acidity in the longer term. Some of these have been running at circum-neutral pH for more than 15 years and are on-going.

We do not run humidity cells specifically but our columns are operated in a similar manner but with lower leaching rates (i.e. ml/kg/month).

So, yes, you can use the KNAG to indicate if and when the samples may acidity. Be careful if you have samples with high S and high carbonate, as the peroxide may decompose before all S is oxidised. If you do need to use the SeqNAG, then the lag is likely to be many years to decades.

I’m familiar with the KNAG tests only to the extent that I think they could well be a proxy for HCs in conjunction with a detailed understanding of the mineralogy. They’re not in common use in North America and I would certainly defer to your discussion.

We also use a biological acid production potential (BC Research confirmation) as a kinetic test, which takes a couple of months. This method is intended to show if bacterial acid generation can be sustained in the material. We sometimes have false positive results for inert materials due to the initial acidification. We use the peroxide acid generation (NAG) tests to correct for these false positive results.

The twenty week minimum humidity was part of the original ASTM standard method and was needed to provide some starting point, since the first few weeks are needed to reach steady state conditions, but it has been superseded in subsequent revisions. How to define the objectives of the testing and duration is still a controversial subject and some consensus in the community of practice is needed.

One outcome the SME humidity cell duration session was that some of the long duration humidity cell tests are being run on potentially acid generating materials to see if water treatment can be deferred, so this may not be needed if the material is accepted to be potentially acid generating, based on the static testing, as long as the impacts of the drainage are properly mitigated.

I have a beta test excel file that I can distribute if anyone wants to help test my system.

Can I have the test excel file so i can cross-check it with real data?

It's posted on my website. Please look at the post I put up earlier today or follow the link to the packer testing paper here:packertest.com