The creation of a tailings dam knowledge base is about acquiring the information needed to perform well-documented risk assessments. Of course, there are many possible ways to create the necessary knowledge base for a risk assessment that is compliant with the new Global Industry Standard on Tailings Management (GISTM). Today, we will discuss a few ways to do so at a high level. At Riskope, we passionately believe that only a blending of approaches is capable of bringing the answers needed for high-quality risk assessments (e.g. benchmarking, causality analyses, etc.). Of course, the proportion of blending and the intensity of the efforts must be scaled as a function of the project size and resources available.
Historical Space Observation
Space observation offers numerous possibilities to recreate the history of a facility. These are based on radar interferometry and stereophotogrammetry. Both techniques can be deployed from manned or unmanned aircrafts. Furthermore, it is possible that on specific sites, good quality stereo pairs going back many years may be available.
Starting in the late 1970s, US satellites started recording stereo imagery of various parts of the globe as part of its counterintelligence efforts. The US has now reportedly declassified those images, which allows civilians to build the history of a tailings facility. We listened to a presentation on this subject by Edumine/Photosat where they showed a real-life example. The precision is claimed to be 15 cm. While that is acceptable to gain a general understanding of a site, like beach lengths, overall slope angle, dam construction phases and deposition history, it is not enough for evaluating the deformations of a dam.
Radar interferometry, together with other specialized sensors, allows us to gain a more in depth understanding of parameters like micro-deformations, humidity, ground temperatures and vegetation stress. If data are available, the analyses can also go back in time using existing databases.
At Riskope, we believe there is great value in approaching the study of a site from a historical point of view using both optical and radar imagery to build the history of the site. Working in Northern Canada, we have shown a client the effects of freezing/thawing cycles on a site where they were previously witnessing anomalous deformations. The fact that these repeated each year over the last six years has been reassuring to those involved.
We recommend using both methods and starting by looking backwards.
Monitoring Records
Each time we start a new risk assessment, we go through monitoring records. It is long, tedious and very frustrating. Even the exact location of boreholes and monitoring instruments is sometimes not clear, let alone their elevation. In those conditions, it is difficult to understand if, for example, an inclinometer is indeed anchored in bedrock or not. Thus, we see the benefit in using databases and business intelligence platforms, but we also see the hazards. These hide behind beautiful graphics that may be anchored in an alternative reality.
And then, of course, instruments break down and may not be replaced as they should. Sometimes their placement follows ease of installation rather than the needs of knowledge-building.
Nowadays, measurements can be broadcast to a central record which can in turn deliver them to a control room. There, graphic displays can render the situation of the monitored parameters in real time. Internet of Things (IoT) adds wonderful data and artificial intelligence (AI) may process all of this and tell us… what, exactly? AI builds its knowledge on what it feeds on; it is not good, as far as we know, in forecasting something it has never “seen.” In that sense, it is not much better than a human being confronted with a new situation.
Thus, again, at Riskope, we believe that the key to allowing IoT and AI to do a better job lies in blending. The blending should include backward space observation with as long as possible monitoring history. Do not start with today’s data and hope the machine can help.
Advanced Documents Search for Tailings Dam Knowledge Base Creation
We have left for last the annoying and less glamorous, yet paramount, part of tailings dam knowledge base creation: to ingest, check and understand the mass of reports that may exist to document a tailings dam. When clients tell us to go visit a tailings operation in order to start a risk assessment, we always try to dissuade them from starting that way. We want to know the dam system before we visit it so that when we do go, we are able to reconnect what we see with what we have learned. Therefore, we start by spending days reading and annotating extant reports. That’s the only way we can discover deficiencies, evaluate uncertainties and come up with the KPIs we need to feed ORE2_Tailings™.
The good news is that we have found a way to streamline this process thanks to a strategic collaboration with a specialized software company. Stay tuned: we will be back on this topic very soon.
