In order to develop a Tailings risk assessment methods comparison we will start by: reviewing a number of existing alternatives to ORE2_Tailings™. This leads to justify the need for the ORE2_Tailings™ approach, discussing what we call the Blackbox objection, which actually applies to all the alternatives and finally the ORE2_Tailings™ procedure, algorithm and results. Alternatives to ORE2_Tailings™ We have grouped possible alternatives into four families discussed below. FMEA FMEA is not a quantitative risk assessment even if it uses indices…
Read More
Today we explore the relationship between Failure modes and catastrophic failures. Catastrophic failure of tailings dam and its water management structures are the likely result of the failure of a number of essential components or any combination of states. We purposely use a different terminology from failure modes because they explain how the dam can fail, but not why. If we look at past events, hydro dams and tailings dam are similar as, for example Oroville and Fundao did fail…
Read More
Most tables of risk comparisons in the literature contain a mix of risks characterized by different levels of uncertainty. In addition, most risk comparisons in those tables offer only single number risk estimates, with no range or error term. For risks such as driving, where fatalities can be counted on large samples, the number is likely to be reliable, at least in some countries. However, even if the risk comparison data are carefully and accurately reported, they can be misleading.…
Read More
Nosso Senhora do Livramento in Mato Grosso, Brazil is an example of tailings dam failure and risk confusion. The dam failure reportedly injured two. Available optical imagery showed a rather contained spill in a flat area at the toe. What we know on the Nosso Senhora do Livramento in Mato Grosso tailings dam At failure, the structure was reportedly 15 m high with a storage volume of 580,000 m³. The material released by the dambreak spread up to 2km downstream.…
Read More
100 years 289 tailings dams failures history is the result brought in by a very detailed research (www.csp2.org) including a freely downloadable database and several explanatory and interpretative papers by Bowker and Chambers. 100 years 289 tailings dams failures history The database contains (on October 7th 2016) 289 failures occurred in 2016-1915= 101 years. Additionally the database contains all reported, failures in the period, from irrelevant/small released volumes, short runout distances, no victims, to the recent large failures (Mount Polley…
Read More
Wall Street and the risks of tailings dam failures Wall Street and the risks of tailings dam failures have been the object of numerous discussions in this blog. A bit more than two years ago we published this. We included a review and a short video from a course we gave in Brazil (Minas Gerais) in 2013, two years prior to the Bento Rodrigues (Samarco mine) dam disaster. We stated that “someone” would soon go to jail for a failed…
Read More
