If you have researched tailings management recently, you have probably encountered a claim along these lines:
GISTM Principle 6.4 explicitly states that alternative technologies to conventional slurry deposition (such as filtered, thickened, or paste tailings) shall be evaluated to eliminate or reduce risks.
That attribution is wrong, and it is repeated across a number of secondary sources. Requirement 6.4 of the Global Industry Standard on Tailings Management is about the Operations, Maintenance and Surveillance Manual. It does not mention tailings technologies at all.
The alternatives requirement is real. It is in Requirement 5.1. This page quotes both from the published standard so the citation can be checked, and then explains what the requirement means physically — which is where a materials-handling supplier has something to add.
What the standard is
The Global Industry Standard on Tailings Management was co-convened by the International Council on Mining and Metals (ICMM), the United Nations Environment Programme (UNEP) and the Principles for Responsible Investment (PRI), and published in August 2020. It contains 15 Principles and 77 auditable Requirements across six topic areas.
Source: Global Tailings Review and the standard itself, Global Industry Standard on Tailings Management (EN, PDF).
Requirement 5.1, quoted
Under Principle 5 — "Develop a robust design that integrates the knowledge base and minimises the risk of failure to people and the environment for all phases of the tailings facility lifecycle, including closure and post-closure" — the standard says:
Requirement 5.1 — For new tailings facilities, incorporate the outcome of the multi-criteria alternatives analysis including the use of tailings technologies in the design of the tailings facility.
For expansions to existing tailings facilities, investigate the potential to refine the tailings technologies and design approaches with the goal of minimising risks to people and the environment throughout the tailings facility lifecycle.
(Italics as in the original, where they denote defined terms. Quoted from page 12 of the published standard.)
Note what it does and does not say. It requires that the outcome of a multi-criteria alternatives analysis be incorporated into the design, and that the analysis include the use of tailings technologies. It does not name filtered, thickened or paste tailings in this requirement, and it does not say those technologies "shall be evaluated to eliminate or reduce risks" in those words. The paraphrase circulating online is directionally reasonable but is not a quotation, and it points at the wrong requirement number.
Two adjacent requirements are worth reading alongside it:
Requirement 6.6 — Include new and emerging technologies and approaches and use the evolving knowledge in the refinement of the design, construction and operation of the tailings facility.
Requirement 4.7 — Existing tailings facilities shall conform with the Requirements under Principle 4, except for those aspects where the Engineer of Record (EOR) […] determines that the upgrade of an existing tailings facility is not viable or cannot be retroactively applied. In this case, the Accountable Executive shall approve and document the implementation of measures to reduce both the probability and the consequences of a tailings facility failure in order to reduce the risk to a level as low as reasonably practicable (ALARP) […]
(Quoted from pages 14 and 11 respectively.)
And for completeness, the requirement that gets misquoted:
Requirement 6.4 — Develop, implement, review annually and update as required an Operations, Maintenance and Surveillance (OMS) Manual that supports effective risk management as part of the TMS. […]
(Page 14. Nothing about tailings technologies.)
Why the distinction matters if you are citing it
A requirement number is a load-bearing detail in a compliance context. An assessment, a planning submission or an academic paper that cites "GISTM 6.4" for the alternatives obligation is citing a requirement about maintenance manuals. Reviewers who check the source will find the mismatch.
If you need to cite the obligation, cite Requirement 5.1 under Principle 5, and quote it rather than paraphrasing — the standard's own wording is more careful than most summaries of it.
What an alternatives analysis means physically
This is the part where the standard's language meets the plant, and where our own domain sits.
Conventional tailings are deposited as a slurry — a pumpable mixture of fine solids and water, retained behind an embankment. The alternatives that an alternatives analysis normally puts on the table are thickened, paste and filtered tailings, each with progressively less water.
Filtered tailings — often called dry stack — change the transport problem completely:
- Slurry is pumped. The infrastructure is pipelines, pumps and a retaining structure.
- Filtered tailings are conveyed and placed. The material is dewatered to a soil-like consistency, moved by conveyor or truck, and compacted in lifts. There is no impoundment holding back a fluid.
That difference is the whole risk argument for filtered tailings: without a pond of saturated material behind an embankment, the dominant failure mode of conventional facilities does not exist in the same form.
It also means the material-handling burden moves rather than disappearing. A dry-stack operation runs a continuous conveying duty on abrasive, sometimes acidic filter cake, frequently over rising and lengthening routes as the stack grows. That is overland conveyor territory, with the usual consequences for belt selection: abrasion-resistant covers, carcass sized for the route rather than the tonnage alone, and impact protection at every transfer.
We are not claiming filtered tailings are always the right answer. They cost more in capex and energy, they are constrained by climate and throughput, and the alternatives analysis the standard requires exists precisely because the answer is site-specific. What is fair to say is narrower: where an alternatives analysis lands on filtered tailings, the transport problem changes from a pumping problem into a conveying problem, and that has design consequences that are easy to under-scope.
The disclosure picture
For context on how many facilities this applies to, the public reference point is the Global Tailings Portal, built and hosted by GRID-Arendal in collaboration with the Investor Mining and Tailings Safety Initiative, with support from UNEP.
- The portal covers more than 1,800 mine tailings dams worldwide.
- It was built from an investor request to mining companies: "As of December 2019, 332 had responded – of these, approximately 100 companies have tailings storage facilities and provided information."
- The initiative behind it represents funds with more than US$13 trillion in assets under management.
Source: Global Tailings Portal — About. Note the portal launched in January 2020 covering 2019 disclosures; it is a voluntary disclosure dataset, not a complete global inventory, and the portal describes itself as a beta.
That last caveat matters and is often dropped when the 1,800 figure is quoted. The database covers facilities belonging to companies that chose to respond to an investor request. It is the best public dataset available; it is not a census.
What we could not verify
Stating this explicitly, because the point of a page like this is that it can be checked:
- Failure-rate statistics. Figures such as "342 tailings dam failures from 1915 to 2021" and "an average of 4.4 failures per year" circulate widely and appear to originate in peer-reviewed compilations. We did not obtain the primary papers, so we are not restating those numbers as established here.
- Dam-type proportions. How the global population splits between upstream, downstream and centreline construction is frequently asserted without a source we could trace. Upstream construction being both the cheapest and the most susceptible to liquefaction is well established; a reliable global percentage is not something we can supply.
- Dry-stack adoption share. We found no dataset giving a defensible global figure for the proportion of facilities using filtered tailings.
If you have primary sources for any of these, we would genuinely like to see them — get in touch and we will update this page with attribution.
Sources
- ICMM, UNEP & PRI (2020). Global Industry Standard on Tailings Management. Full text (PDF) — all requirement quotations above are taken from this document, with page numbers given inline.
- Global Tailings Review — publisher, structure and topic areas of the standard.
- Global Tailings Portal — About, GRID-Arendal — disclosure counts and initiative background.
Quotations verified against the published standard on 23 July 2026. Corrections welcome.
Related engineering reading: Iron Ore Conveyor Belt Selection covers the belt decisions that apply to abrasive mining duty, including steel cord for long overland routes.
