IN LISBON: Collapsed shafts lie beneath the ground, while tailings and mine waste remain scattered across valleys and rivers. Many mines had closed before environmental oversight existed, or abandoned as prices fell and operators moved on – leaving behind a legacy that was never fully accounted for.
Decades later, the consequences persist. Polluted waterways, contaminated soils, and long-term health concerns are affecting surrounding communities, often far from the public view.
In Portugal, there are about 175 abandoned mining sites, of which 60 are old uranium workings, as reported by Elsevier.
Out of the 175 abandoned mine sites, 96 are considered to have a planned intervention, a report from Portuguese state-owned Empresa de Desenvolvimento Mineiro (EDM) says.
EDM is responsible for the environmental rehabilitation of abandoned and degraded mining sites, acting under an exclusive concession from the state.Most modern day mines are now reclaimed during and after the completion of mining activities. However, prior to the enactment of environmental laws, most abandoned mines were not reclaimed before the 1970s.
As one Canadian mayor said, on the occasion of the ceremony to mark the end of a great work of rehabilitation of an abandoned mine in his country: “What happened in the past reflected a different time with different values and ignorance of a different age. We all have to be praised today by the fact that governments and organisations contributing to cleaning up the sites and solve some of the social and economic impacts, are not the ones that caused the damage. This is not an act of contrition of the society. This is not about the past. It’s about the future. This is an investment and a statement of optimism.”
As Europe races to secure critical minerals and reopen old districts under a new banner of sustainability, the question emerges: can a country responsibly open new mines without confronting the ones it abandoned first?
A hazardous consequence
This news comes in response to a new collapse of a mine tailings structure occurred in late January 2026, at Almonty Industries (ASX:AII) Panasqueira mining complex, following several days of intense rainfill in central Portugal.
As a result, large volumes of mining waste from a legacy site were released into the Cebola stream – a tributary of the Zêzere River – highlighting the vulnerability of aging and insufficiently remediated mine waste facilities in the region.
An Almonty spokesperson tells Mining.com.au this is a former facility that is not part of the currently licensed and actively managed waste operations at the mine site and is separate from the mine site.
“Importantly, there were no injuries and crucially, the river water was never contaminated and any minor effects identified to date being temporary,” the company spokesperson says.
In response to the latest incident, the public company responsible for Lisbon’s drinking water supply, Empresa Portugesa da Águas Livres, began water sampling operations at multiple locations across the affected catchment.
The aim is to assess potential impacts on water quality. Mining Watch Portugal says this move reflects growing concerns that repeated pollution events at the Panasqueria site may post risk beyond the immediate mining area.
Scientific studies have documented elevated concentrations of arsenic and other heavy metals in soils, sediments, and water bodies downstream of the Panasqueira tailings. The contamination is linked to acid mine drainage processes and represents a threat to ecosystems, agriculture, and human health.
Acid mine drainage occurs when exposed sulphide minerals create sulphuric acid, leaching heavy metals into water sources.
Almonty notes that the displaced material consisted “solely of coarse sand tailings – not fine slimes or any material that could pose contamination risk”.
“The matter has been fully resolved and no long-term impacts have been identified,” the company says.
Although the Panasqueira mining complex has been in operation for more than a century, little primary exploration has been carried out outside the active or past time workings. In Almonty’s technical report of Panasqueria, the hills surrounding the mine contain many old pits and shafts left from old small tungsten vein hand mining operations.
Portugal’s unfinished inventory
The most recent collapse has directly affected nearby agricultural land, including olive groves and vineyards, according to Mining Watch Portugal.
Mining Watch Portugal says that landowners are demanding accountability and compensation from the mine owner for environmental damage and economic losses.
Almonty, through its in-direct wholly owned subsidiary Belrat Tin and Wolfram owns the Panasqueira Mine. The mine has had three known failures at the tailings facility over the past decade.
Being one of Europe’s most historical sources of tungsten and tin, the mine has generated enormous volumes of mining waste over more than a century of operation. During 1937-2016, a total of 40 million tonnes of rock was mined, producing 128,000 tonnes of tungsten, 6,600 tonnes of tin, and 32,000 tonnes of copper.
Many countries across Europe are no stranger to mining. Portugal, specifically, has a historical mining history dating back to the Roman era. Portugal hosts the sixth largest copper mine in Europe – the Mina de Neves-Corvo Mine – which was sold in December 2024 by Lundin Mining (TSX:LUN).
Portugal’s mining sector has a market size of €580.1 million ($971.19 million) as of 2024 – ranking eighth in Europe for revenue, as reported by MinEx Europe.
Despite its significance, the nation still has an issue of abandoned mines that is yet to be dealt with.
According to Science Direct, there are several hazards of an abandoned mine or old mine working, including someone falling into an open pit or quarry, deadly gases, cave-ins, unsafe structures, and water hazards – to name a few.
The Minas da Borralha mine is one example of these hazardous consequences, following being abandoned in 1985.
In 1993, concessions were terminated and the area was designated for environmental recovery, but heavy metal pollution remains, according to the Iberian Mining Observatory.
As of 2024, the Cávado river and its tributaries were recorded as polluted with cadmium, mercury, copper and other heavy metals as a result of acid mine drainage from the Borralha Mine.
Several studies have shown how the surrounding soils have high concentrations for arsenic, cadmium, lead and mercury – all of which are considered extremely toxic to the environment and human health.
The Iberian Mining Observatory states that no significant remediation efforts have been carried out even through the Empresa de Desenvolvimento Mineiro, which has a concession from the State to manage environmental liabilities.
Another example of Portugal’s abandoned mine issues is the São Domingos Mine which was once considered an important copper mine until 1966. The facilities were abandoned, leaving nothing but a ghost village with extremely polluted water and soil, as reported by Atlas Obscura.
A global reckoning
The issue of abandoned mine sites is part of a larger issue that is becoming harder to ignore across the world. As Mining.com.au reported following the search of missing toddler Gus Lamont, there are more than 190,000 abandoned mine features throughout Western Australia.
Speaking to this news service, Western Australia’s Department of Energy, Mines, Industry Regulation and Safety (DEMIRS) General Manager of the Abandoned Mines Program Tara Read says there is still a lot of data out there that has not been categorised yet.
“For about an 11-year period, the Geological Survey of Western Australia went out and identified the locations of legacy mining associated history,” Read says.
“You think about it, Western Australia has a really rich mining history. There has been economic development through mining happening for over 100 years. The legislation associated with the protection of the environment and those sorts of things happened much later.”
Read says the abandoned mine features identified in Western Australia are in relation to communities, which is where some of those risks are going to be presented to the community.
“We’ve just started programs to start looking at dealing with those areas,” she tells this news service.
When the abandoned mines program first launched in 2015, one of the questions that was commonly asked was although there is all this inventory, where do the resources go first.
“We can’t be everywhere at once,” Read notes.
Data from MDPI reveals that there were more than 95,300 active and inactive mines identified in Australia, as of 2020. Inactive mines constituted the vast majority, totalling 89% of these numbers.
Among the inactive mines, the majority (68%) were characterised as neglected, totalling 58,017.
Portugal’s 175 identified abandoned sites are not just statistics in a report – they represent an unresolved chapter in the nation’s extractive history.
As Europe and the world accelerates efforts to secure domestic supplies of critical minerals for the energy transition, credibility will hinge on how new mines are designed, as well as how old ones are addressed.
Write to Aaliyah Rogan at Mining.com.au
Images: Mining.com.au, EDM & Almonty
