I know. The expression is supposed to be, “A Diamond is Forever”. Thank you De Beers, but that really isn’t true. Not to knock too much of the luster off of the very famous slogan, but take the example of industrial diamonds that are used as abrasives for cutting and drilling. Those wear out. Bye bye diamonds.
Okay, this article really isn’t about that. How is it that I always get so far off topic?
In tailings facility closure, we talk about perpetual closure. Which is a really long time. Forever. Longer than a diamond.
In tailings facility closure, we talk about perpetual closure. Which is a really long time. Forever. Longer than a diamond.
In perpetuity, you could have an infinite number of maximum credible earthquakes, and an equal number of maximum probable floods (as my friend Steve Vick has written). That is a lot of biblical-sounding events (next we will have frogs or locust!) And then there is that infinite period of the erosive forces of wind and water. How can these tailings facilities ever possibly withstand all of these forces and abuse forever? Which yields first? An immovable object or an unstoppable force? The immovable object vs. an unstoppable force paradox rests on two incompatible premises: that there can exist simultaneously such things as unstoppable forces and immovable objects. The “paradox” is flawed because if there exists an unstoppable force, it follows logically that there cannot be any such thing as an immovable object and vice versa. (Reference Wikipedia: https://en.wikipedia.org/wiki/Irresistible_force_paradox)
The way around this paradox for us it to make sure that the closed tailings facility is more robust than all of those things that nature will throw at it.
How long is perpetuity, anyway? Well, pretty long. That’s for sure. Is it really forever, with respect to tailings facility closure? Most rational minds would agree that maybe in this case, it’s only until the next glacier comes along and scrapes it away.
That feels much better, now, doesn’t it? Try to not think about it, and do a good job.
Comments (2)
Arturo Fahrenkrog
January 22, 2020 at 9:35 amRespectful Bryan, The current trend in instrumentation for determining the appropriate operation of tailing dams and landfill has involved, until recently, the use of a network of traditional, vibrating wire and other local instruments. These sensors are distributed in sections in the foundation and base of the dams and landfills and their readings are done manually, giving not too much traceability and long term monitoring. The development of hydraulic deposit sand dams has actually reached heights in excess of 300 m, with instrumentation schemes that consider sensors whose conductors and electrical cables exceed 3 to 4 thousand meters in length. In order to minimize operational budgets, the work proceeds by construction phases where these cables are subjected to periodic splicing and, furthermore, to accidental cuts, producing low signal conditions and eventually signal loss, with poor survival rate for ever as per you well indicate. All of these conditions render an operational diagnostic program unreliable. The instrumentation scheme for the evaluation of the behavior of a mining closure or landfill monitoring condition becomes a financial burden, as new instruments have to be installed measuring water table variations and their stabilization. Under these conditions, the new records produce results that should be interpreted with caution. The recent availability of distributed, Fabry-Perot and interferometry fiber optic sensing (FOS) technology provides a tool to overcome long distance conductor signal decay of the individual piezometers and point thermometers, and the limited accuracy of the automated readout equipment. Air dryness, wind and static interference generate a harsh environment for standard electric signals transmitted over long distance cables: another reason for selecting FOS, ShapeArray and InSAR technologies. The latest generation methods of fiber optic measurement systems are producing precise readings and data files which are being used for operational diagnostic purposes, with particular emphasis in controlling the hydraulic sand deposit sequences of the fills. The protection given for a long term during construction to fiber optic conductors and sensors allows strain free operation, against overburden pressures. An early planning of the installation of fiber optic sensors, in accordance to the long – (for ever) – life expectancy of the reinforced conductors, nowadays allows us to control the contained water and ion concentration in the closed loop of the tailing and lixiviation waters in the basin. The early installed, long lasting fiber optic distributed temperature fiber, Fabry-Perot piezometer nets and ShapeArray or interferometry extensometers are the best choice and backup for guaranteeing a non-invasive and harmless insertion of these devices in the mining environment. Examples of these installations and data management are in tailing dams and copper lixiviation process, with emphasis on the diagnostic of their geotechnical conditions, and focused on – a near for ever – mine closure instrumentation with fiber optic sensors installed in early planning stages for a Robust Risk Management monitoring scheme. Best regards!
admin
January 24, 2020 at 10:04 amArturo, many thanks for the detailed and very thoughtful comment. I appreciate the information and the support you have provided. All the best.
Bryan
Comments are closed.