CONTACT: Lindsay Newland Bowker 207 367 5145/

DATE: October 1, 2016





According this 2014 report by the Brazilian Government, Brazil has 633 tailings dams, the overwhelming majority built after enactment of the   2010 statutory overhaul. 144 are large enough to cause catastrophic social, environmental economic  and public liability loss in the event of failure . In this report, Brazil classifies only 32 of the 633 facilities as high risk  by its procedures for analyzing risk.  Those procedures however are more like the standard hazard classification which speaks simplistically  and narrowly to the issue of how much harm a given outflow could cause.  They do not recognize whether what is built and operating  can be reasonably expected to attain environmental standards. For example it does not recognize the different propensity for failure  for a given height and capacity configuration based on ARD, rate of raise, or dam design, drainage system, capacity to separate silt from sands , proportion of fines, dryness through the stack and other tailings specific characteristics not shared by water dams.


All will recall that the July 2015 inspection report prepared by VOG BR gave a satisfactory rating to the Fundao.  As VOGBR explained in a briefly posted letter that is excerpted at length at our wordpress, the report was a required annual compliance report whose form and content is dictated by the regulations and law.


VOG BR wrote that Samarco did not  allow them to take any independent measurements or visit the site.  Samarco, they said,  gave them the data and contractually specified the analysis to be used.  This same level of “annual safety inspection” pursuant to law has presumably  attended oversight of all of Brazils large dams

 Vale Tailings Dams Map.png

Photo From

Taking a more  comprehensive, forensically informed view of risk  and evaluating Brazils legal framework, its obviously  low  level of technical competence   in mining, we believe  all 144 large tailings facilities in Brazil should be considered at significant risk of failure and a program of independent multi-disciplinary  risk assessment  be undertaken for all 144. All upstream dams higher than 50 m should receive top priority attention..  The  immediate priority should  be on the  15 mega dams of extreme height and size relative to the world’s tailings dams.  Vale’s  mega dam at the Tapira Complex, already exceeding permitted capacity  and in process of further expansion and already evidencing cracks and other signs of strain  has been widely identified as of particular concern. Our reasons for  considering all 144 large tailings dams at risk are:


(1) the 2010 statute reform did not address any of the root causes of catastrophic failure focusing instead on the structure of  criminal and civil liability. Under that law the fatal flaws in the Fundao were not detected or addressed until the worst failure in recorded world history actually occurred


(2) Vale controls 114 of 633 total TSF facilities  and accounts for a very significant  part of all of Brazils iron ore production  generating 200 million tonnes of ore per year  more than  40% of that in tailings and wastes in just the Iron Quadarangle area.. Vale aim to increase throughput in the 19 Quadrangle by 50% by 2030. Its own 2013 self assessment of the safer alternative of paste thickening  and dry stack concluded  most of its  presently generated tailings did not meet technical criteria for the safe alternatives of paste thickening and dry stack.  Only 4 of its 114 TSF’s nationwide , 4%,  met the criteria for dry stack or paste thickening.  Vale  succeeded in making Brazil back down from post Fundao failure reforms that would have put controls on height and rate of rise ( per globally recognized best practice) and banned upstream construction for large dams. (Eisenhammer) Vale, 50% owner of the Samarco vetted the major expansion and ok’d proceeding even though its own consultant flagged the absence of adequate capacity on the Fundao and the absence of any plan or space on site to provide capacity .  Vale’s inventory  of TSF’s includes many, if not most, of these very large tailings dams. 


(3) there is no mining  competence within any of the permit issuing entities or within the state of Brazil so even if the legal framework addressed root causes of catastrophic failure there is no technical capacity within government to determine whether environmental and conservation standards are actually attainable . Virtually all of the 144 large tailings dams and the 15 mega talings dams were permitted  with no technical competence on the part of regulatory oversight


(4) Minas Gerais alone, a major center of mining in Brazil, .seems both inept and a victim of complete regulatory capture (as was and is the case in Brtish Columbia) . Rio Pomba had two prior serious events (2003 and 2006) before the final very serious failure on 2007.   Minas Gerais is responsible for 3 of the world’s 18 very serous failures 1/1/1996-12/31/2015, 17%)   and 3 of the worlds 20  serious failures post 1996,15%.  We don’t need details on Minas Gerais’ total ore throughput to know that this  is out of scale with Minas Gerais’ rank  in global ore throughput..


(5) Brazil, since passage of its 2010 statute has embarked on a massive improperly regulated expansion of metals production sowing the seeds for catastrophic failure ( There were only 241  tailings dams in Brazil in 2011, 641 by 2012.( see Figure  9  of cited report)

 herculao dam failure_

Herculano Tailings Dam Failure Minas Gerais

To Brazils credit and pursuant to the 2010 statutory overhaul, Brazil here has at least made some account of its TSF’s and reported out a few useful publicly available stats. Every nation should publicly report and monitor the condition of all permitted large TSF dams as this Brazil report does. It’s major flaw, however is that it focuses on a common set of measurements amongst all types of dams and neglects to address key elements of risk and function that are use specific. For example, no discussion of upstream construction  and rate of raise in tailings dams.


As you may know ICOLD, the International Committee on large dams  does not keep track of tailings dams for fear their terrible safety record would reflect adversely on public perception of water dam safety (Kiernan 2016)  Brazil here at least counts and gives basic stats on its tailings dams. and we can, because of our deep immersion in the forensics of the worlds mining catastrophes make some inference from these data on the likely massive public liability already formed in these 144 large TSF’s.


It is our advocacy that Tailings Dams require their own risk assessment criteria and their own relevant stats and legal framework.  Our advocacy is that every permitting district should have an independent multi -disciplinary Mine Review Board  separately appointed and mandated in statute similar to Buildings Departments and the Inspection process for construction of large buildings. They should have the power to act against or in lieu of permitting districts that are not applying existing authority, a reality that is itself a root cause of failure ( BC Auditor Generals’ Report 2016)


This report  applies the same size categories to tailings dams as to other dams using the ICOLD definitions  where a large dam is defined as a height greater than 15m or a capacity greater than 3 million cubic meters. 


In this case the criteria that define a large water dam and those that define a large talings dam are reasonable and fit with the forensics of tailings dam failure. Tailings dams of 3 M cubic meters are capable of catastrophic failure which Dr Chambers & I define as a release > than 1M cubic meters.( Bowker Chambers 2015, Bowker Chambers 2016)  In a total failure  30%-50% of contents is generally released.( Rico 2010 and forensics)



In general as a risk analysts and as an anlayst in general, I discourage comparisons between water dams ( purpose built to completion to  a known range  of flow with materials rigidly meeting specific specifications, retaining only water  and build as you go and mostly earthen from  materials at hand, retaining various toxic materials and variability in the structural integrity of materials available for each raise.  Obviously they are not meaningfully  comparable.. 

We have to reiterate that the meaningless manufactured stat that tailings dams fail at a rate 10 times water dams  should be permanently retired and never again cited. by any responsible researcher, journalist or spokes person.


Each type of retention dam should be assessed for its own distinct  inherent engineering and failure risks based both on contents and means methods and materials of construction.


To discourage comparisons with water dams it would be better if water dams were separately reported and monitored on standards suitable for them and mine tailings  ( and other type of waste and  waste dams eg those retaining pregnant leach solutions) were reported and monitored on their own terms for risks specific to the dam type.)




Ignoring the comparisons by dam type in this report ( and resisting any urge to cite them on a comparison basis) here are some of the stats in this 2014 Brazilian government report.


per figure 4:


519 of the 663  Brazilian tailings dams are not “large dams” by definition and therefore also not capable of catastrophic failure  as defined in Bowker Chambers 2015 and Bowker Chambers 2016.


144  of the 663 are large dams.


of these  15 have a dam capacity of  greater than 75 M cubic meters ( 7 of these > 200 M cubic meter  capacity ( see Figure 10 as well)


The distribution of Brazils tailings  dams by height is show at figure 12 on page 29


The Fundao was 74 M high at failure and had a capacity of 62 million cubic meters. Mt Polley was 40 m high at failure and had a capacity of  75 million cubic meters ( Chambers Bowker Failure Data Base 2015, revised 2016)


 As we learned lately BHP did not even have a geophysicist on staff before the man made catastrophic failure of the Fundao and had no informed risk management policy on the many TSF’s at its mines all over the world..  Samarco had an independent Tailings Review Panel  but the effect of that on loss prevention and control is apparent.  It s not an exaggeration to consider all 144 large dams in Brazil as at risk .


Dr. Chambers & I  know from our deep dive into the forensics of all catastrophic TSF failures  recorded history ( Bowker Chambers 2015, Bowker Chambers 2016) that the greatly expanded volume of ore production needed to attain a unit of finished metal as grades fall precipitoulsly worldwide is accommodated mostly by pushing existing TSF’s beyond their design capacity in height, volume, years of useful life and foot print.  Chuquicamata , for example,   still planning to use  its same  43 SqKM  1985 TSF for its current massive underground expansion. At Samarco  it was known the Fundao did not have capacity for the planned expansion. Vale who control 144 of Brazils tailings dams ( see Quadra 4 p 51) signed off on that. All knew the Fundao never had its two key engineering requirements for safe operation from the beginning .  All knew there was no identified vetted plan for expanding onsite capacity to adequate and soundly manage the volume and rate of tailings deposition that the expansion would require.  That happens everywhere.  We rarely see  a specific focused review of tailings capacity for these big throughput expansions and investors , before Fundao, never thought to ask these questions.


Dr. Chambers and I have been saying for two years now hat the records tells us the first and most urgent regulatory and public attention must be directed to the already accumulated but not  yet manifest catastrophic failure in existing permitted operating facilities.( Bowker Chambers 2015, Bowker Chambers 2016)


It is clear that this cannot be a self evaluation and it is clear that Minas Gerais and most permitting districts do not have the competence to  either oversee or conduct these re evaluations.


These re evaluations have to reach well beyond the usual routine proximate cause of failure.  The world record of failure is now perfectly clear that root causes of catastrophic failure  which lay behind these incompetent or just wrong engineering choices cited as “proximate cause” ( Bowker Chambers 2016)



Brazils risk classification and its overhaul of mining law miss what have been identified as key root causes of catastrophic failure( Bowker Chambers 2016)



Brazil needs to stop the clock on its aggressive mine expansion agenda, assess the liabilities they have allowed to accumulate in this massive improperly regulated expansion post 2010 and form a strategy for unwinding  that liability.  Unfortunately it seems that present law des not provide any response until the destruction happens.  They need new law now to specifically address what they will find when they undertake a more meaningful risk assessment than is provided in this 2014 perfunctory report.





Blight, Geoffrey (2010). “Management & Operational Background to Three Tailings Dams Failures in South Africa.” Chapter 42, Slope Stability in Surface Mining, ed. Hustrulid, W.A., McCarter, Kim, Van Zyl, Dirk, Society for Mining Metallurgy and Exploration, e-book, 2010.


Blight, G.E. and A.B. Fourie (2004). “A Review of Catastrophic Flow Failures of Deposits of Mine Waste and Municipal Refuse.” Proceedings International Workshop, “Occurrence and Mechanisms of Flow-like Landslides in Natural Slopes and Earthfills.” Sorrento, 19-36, Picarello (ed), Patron, Bologna


Bowker, L.N. and Chambers, D.M. (2016).” Root Causes of Tailings Dam Overtopping: The Economics of Risk & Consequence”  Proceedings of “Solutions 16”, (September 2016 ) ( presently in compilation by Solutions16  meanwhile pre publication copy available from the authors) 


Bowker, L.N. and Chambers, D.M. (2015). “The Risk, Public Liability, & Economics of Tailings Storage Facility Failures.” July 21, 2015,, (June 14, 2016).

Chambers D.M. and Bowker L.N.(2016)  Tailings Dam Failures 1915-2015 (excel Free publicly downladadble)


Chambers, D.M. (2014). “Options For Defining Environmental “GO/NO-GO” Zones For Mines.”January2, 2014, (June 14, 2016). Commissioned Directed By Bowker Associates)





Eisenhammer, S and Nogueira, M (2016). “Brazil Mining Dam Reforms Unsettle Companies, Do Little for Safety.” Reuters, May 11, 2016


Kiernan, Paul (2016b). “Engineers Say Brazilian Disaster Shows World-Wide Danger from Hoover Dam-Size Earthen Structures Holding ‘Tailings’ Waste.” Wall Street Journal (WSJ), April 5, 2016


Mt Polley Expert Panel (2015). “Report on Mount Polley Tailings Storage Facility Breach.” Independent Expert Engineering Investigation and Review Panel, Province of British Columbia, January 30, 2015.

 ADDITIONAL BACKGROUND ON MINING IN BRAZIL  Excellent and through Engineering and Minig Journal 2011 article on the economics of mining, economic policy, economic and political history of mining in Brazil( n English)

This thesis which also combines analysis of water dam and tailings dam failures has good text and photos of all of Brazils failed dams  (in portuguese)

Mining.Com’s 2013 profile of 10 largest foreign investments in Brazil Mines..No details on tailings..just thumbnail sketches  Anglo America is prominent on the list

Vale’s History In Its own words  .

Vale’s Self Assessment of  Possibility of Using Safer  Sounder Tailings  Storage

Lindsay Newland Bowker, CPCU, ARM Environmental Risk Manager

Bowker Associates

Science & Research In The Public Interest

15 Cove Meadow Rd.

Stonington, Maine 04681


207 367 5145

About lindsaynewlandbowker

Bowker Associates, Science & Research In The Public Interest, is an independent non profit providing self initiated pro bono analysis on key issues with a potential for massive adverse environmental impact . Bowker Associates has been an internationally recognized and cited voice in analysis of all significant tailings failures since 1915 mainly through and for reserach insittute World Mine Tailings Failures. In 2017 Lindsay Bowker was princial author of her third major work on the economics of tailings failures. Bowker, L.N.; Chambers, D.M. In the Dark Shadow of the Supercycle Tailings Failure Risk & Public Liability Reach All Time Highs. Environments 2017, 4, 75. A peer reviewed journal published investigation of the cowboy economics of the supercycle and the resulting escalation on the number and magnitude of catastrophic failures. Ms. Bowker was principal author of two other seminal works one looking at root causes of failures Bowker, L.N.; Chambers, D.M. Root Causes of Tailings Management Failures: The Severity of Consequence of Failures Attributed to Overtopping 1915–2015. In Proceedings of the Protections 2016, Fort Collins, CO, USA, 14 June 2016. [Google Scholar] In 2015 Bowker Associates compiled all known accouns of all TSF faiures in recorded history analyzing these data in the context of global mining economics 1910-2010 ( Risk, Economics and Public Liability of TSF Failures, Bowker/Chambers July 2015) The third annual update of this globally referenced and used compilation was just released at Researchgate. ( In 2014 Bowker Associates commissioned Dr. David Chambers to undertake two technical works: (1) development of technical go no go criteria for vetting mine applications tp:// and (2) a case study of Maine's Bald Mountain, an un mined low grade high risk VMS deposit demonstrating the efficacy and accuracy of two risk assessment tools in vetting mine proposals In Maine, Bowker Associates has deeply engaged and been a public voice in the Searsport DCP LPG Tank, The Cianbro proposal for a Private East West Toll Road, JD Irvings rolling pipeline of Bakken crude to its plant in St. John and review of Phase II plans at The Callahan Superfund site in Brooksville, Maine, and Maine's revisitation of mining in statute and regulation... Our only “client”: is always “the pubic interest”. Our model is to focus on only one or two issues at a time so that we have a substantive command of the relevant field as our foundation for ongoing engagement. Our core work is in envirommental risk management, science and technology as well as bringing any available “best practices” models to the fore. The legal and regulatory history/best models are also a major thrust of our work in building and evaluating public policy. Director/Principal Lindsay Newland Bowker, CPCU, ARM is a recognized expert in Environmental Risk Management., Heavy Construction Risk Management and Marine and Transit Risks and has more than 3 decades of engagement in buiding public policy. Appointed by Governor Mario Cuomo to New York State Banking Board (served 1986-1996); President New York Chapter Chartered Property and Casualty Insurers; Environmental Committee, Risk and Insurance Management Society; Director, Convenor/Co-Chair Bermuda Market Briefing "From Captive to Cats" Hamilton Bermuda. Published Articles of Significance The Risk Economics and Public Liability of Tailings Facility Failures, co-authored with David M. Chambers, July 2015 Beyond. Polarization: Superfund Reform in Perspective, Risk & Insurance Managing Risk For Loss Prevention & Cost Control (Jan. 24, 1997). Lead Hazards and Abatement Technologies in Construction: A Risk Management Approach CPCU Journal 1997 Employee Leasing: Liability in Limbo Risk Management June 1 1997 Environmental Audit Privilege and the Public interest Risk & Insurance Managing Risk For Loss Prevention & Cost Control, April 1997 Asbestos:Holes In Abatement Policies Need To Be Plugged, Lloyd’s Environmental Risk International, May 1993 Editor Published Letters Evironmental Risk Management Beware of Facile Policies Like Fetal Protection Business Insurance 1995(?) High Court Review May Increase Sale of Bank Annuities Business Insurances August 8, 1995 Professional Profiles Protecting the Big Apple’s Core Managing Risk For Loss Prevention & Control December 1996 Major Career Highlights First rigorous analysis showing Relationship Between declining ore grades and TSF Failures of increasing consequence ( July 2015) FIrst Documentation that Gentrification Has Same Impacts as Unassisted Displacement from Urban Renewal Sites Direted Court Ordered EIS of FHA Mortgage Scandal Created Nation's First Homeownership Program for Low Income People (SHIP) Created Earliest Geographic Information Systems Using Defense Technology Developed By IBM Designed and Conducted Parallel Census Count to Show Systematic undercount in minority neighborhoods Documented Bias in ISO Territory Rating Plans for Private Passenger Auto Insurance Using ISO's own Rating Techniques Demonstrated Inherent Bias in Mortgage Policies of Banks With Inner City Branches Demonstrated that NY Telephones Plan for Area Code Split To accommodate anticipated cell phone demand was not efficient and would exhaust in 5 years ( which it did) Undertook First Systematic Evaluation of Child Protective Services Caseload Using Multi Variate Analyic Techniques Developed Child Protective Caseload Management and Tracking System (CANTS) and directed implementation in 4 client states including Illinois, Florida and New York Created and Ran Office of Risk Management for NYC DEP the Nations largest Water & Sewer Authority . Designed, Created and Administered Nation's First Owner Controlled Insurance Program (OCIP)for High Risk Tunneling Education Masters NYU Graduate School of Public Administration BSC New School For Social Research Maine Public Schools Deering High School
This entry was posted in BHP, Bowker Associates Science & Research In The Public Interest, Brazil 's High Grade Iron Ores, Brazil Tailings Dam Failure Risk, David M. Chambers, Lindsay Newland Bowker, Minas Gerais Mining Oversight, Samarco $44 billion lawsuit by Brazil, Samarco Dam Failure, Samarco falha de barragem de rejeitos, Samarco Indepemdent Panel Report, Tapira Complex, Uncategorized, Vale Indictments, Vale SA., Wonder Dam III. Bookmark the permalink.


  1. Pingback: Especialista que revelou dimensões do TsuLama ao mundo, analisa relatório da ANA e faz alertas preocupantes sobre situação de barragens de rejeitos no Brasil | Blog do Pedlowski

  2. Chris Marshall says:

    Hi –

    Do you know where I can find data on tailings containment method by asset for Vale S.A.? I’m interested to see if they primarily utilize the upstream method versus other alternatives.


    • Chris,

      As tailings are the #1 source of catastrophic, non remediable environmental loss, and unfundable public liability one would think all permitting authorities would maintain this data as part of oversight and make it publicly available. Our advocacy is that all should do so. Through annual reports or other data listing mine assets it is possible to then search by asset name and piece together bits of data on the TSF infrastructure for each.. Bowker Associates is trying to build a global census of large TSF’s and is using that method..Tough sledding as most technical reports even on expansions never even mention tailings or waste management.
      My guess is that many if not most of Vale’s TSF’s are upstream and that the high production sites also push the established best knowledge on height and rate of raise..
      Public interest and environmental advocacy should be pushing loud and hard both for permitting entities to provide this immediately and also pushing all large miners for full disclosure..
      Meanwhile, the more we who are willing to do the tedious work of building this information and presenting it publicly are able to accomplish, the more we can effectively we can keep the spotlight and conversation on sounder tailings management policy.
      Write to me at and I will send you the format for my excel global census.. I encourage you do do this work and I will give you what support I can.. My database tracks the complete history of each mine site ..a new record with each new owner, each expansion, or each new TSF. That approach is important to understanding Vale’s role in forming the incurred but not yet manifest public liability in Brazil as well.. It is important to understand what accrued on whose watch.

      Chris, thank you for whatever work you are undertaking to build this picture of Vale’s history in Brazil and to understand how much of Brazil’s preset public liability in existing tailings accrues to Vale.

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