GeoLog

Energy, Resources and the Environment

Imaggeo on Mondays: What happens to mines when they become redundant?

Imaggeo on Mondays: What happens to mines when they become redundant?

When the minerals run out, or it is no longer profitable to extract the resources, mines shut down. Prior to issuing a permit for the exploitation of a resource, most regulators require assurance that once the mine closes it, or the activities carried out at the site, will not present a risk to human health or the environment.

Ongoing monitoring of a mine once it is decommissioned is required to ensure this is the case.

“The goal of my work is to study the environmental impact of mining waste in the north-east part of Algeria,” explains Issaad Mouloud, author of today’s featured image.

Algeria has a long history of mining. Since the antiquity and the time of the Berbers, many minerals and ores deposits were exploited. The northeast was the most productive region in the country. The geology of the study area is composed of magmatic and metamorphic rocks, sandstone and limestone.

Kef Oum Theboul mining district is located on the Eastern cost of Algeria, 4 km west of the Tunisian border. It is located 15 km from the town of El Kala. The Kef Oum Theboul site covers an area of 26.6 km2 and which contains copper lead and zinc ore

Discovered in 1845, the Kef Oum Teboul ore deposits were mined from 1849 to the 1970s. The Messida ore plant, pictured above and located not far from the Kef Oum Teboul deposit, is one of Issaad’s study sites.

The ore plant, situated in the Algerian Mediterranean coast, on Messida beach (located 6km from Kef Oum Teboul) processed copper, lead and zinc mineralizations.  Processing at the plant started in 1899.  It had three water jacket furnaces, with a capacity of 50 tons of ore per 24 hours. The obtained matte contained 20-22% copper, 200 grams of silver and 11-12 grams of gold per ton.

“The plant is now totally destroyed but mining waste, mainly sulphur ore and slag, is still stored in the Messida area,” explains Issaad, who goes on to say “the main pollution factor which I study is the acid mine drainage and heavy metals.”

 

Abandoned sulphurous ore and slag stored in the ruins of the ore processing plant of Messida. Credit: Issaad Mouloud

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: Breath from the underground

Imaggeo on Mondays: Breath from the underground

The heat seeping from the geothermal area which is part of the Krafla volcanic system in Iceland, ‘powers’ the steaming vent at Hverir (Hverarönd). The area is well known for its mud pots and sulphuric gas fumaroles, complete with pungent eggy smell.

Some of the vents are in fact boreholes drilled in the 50’s for sulphur exploration which have been turned into fumaroles, the steam is a result of a steam zone above boiling groundwater. High temperature geothermal areas are a byproduct of Iceand’s volcanic setting and the energy released can be used to power homes and infrastructure. Indeed, geothermal power facilities currently generate 25% of the country’s total electricity production. You can read all about that in an Imaggeo on Mondays we published a couple of months ago.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Light years from home – a geologist’s tale

Light years from home – a geologist’s tale

In a departure from the usual posts we feature on the blog, today Conor Purcell (a freelance science writer) brings you a thought provoking science fiction piece. Grab a drink and dive into this geology inspired adventure!

“It’s typical geology for a rocky planet” K reported. “Captured beneath the ocean at its northern pole, the core is a mix of metamorphic and sedimentary rock, with sand and fossilized organisms of the non-intelligent form. Nothing unusual.”

“We should use our new systems for this analysis,” It thought to itself. “Best to begin with a rocky planet.” K was the collective thinking entity of its group, a unified consortium of representatives now located across interstellar space: their task to find intelligent life beyond itself.

Here, on the orbiting cube, lying lengthways in front of K, and secured within the hold of the onboard core analyser, was a long cylindrical section – a core – of rock and mud which had been excavated from the planet below. K was now beginning the routine inspection performed on each of the cores acquired across the surveyed planets.

“Inspect all elements and produce time-series of environmental parameters relevant for the planet” K commanded itself.

It was then that something unusual triggered a notification in its Thought Centre – something it had never experienced. “What is this?” it asked.

For millennia, K had been searching for evidence of intelligent life on exoplanets beyond its own host star. In earlier times ground based receivers had been constructed and used to scour the endless black sky, and although life had been discovered to exist almost everywhere, without exception it took the form of mindless cellular or multicellular organisms. No trace of another Type 1 civilization had ever been found. Even as K’s technology advanced, observing and measuring the atmospheres of millions of remote planets to seek out the signatures of machine and biological life, and now even visiting those remote worlds, no sign of intelligence had yet been discovered.

What now caught the attention of K’s Thought Centre was a narrow section of fine material which appeared to have been laid down in a remarkably short period of time, during just twenty solar orbits. “This geology is unique,” K thought.

“On a planet that contains layers stacked typically over tens of thousands or millions of years, what kind of mechanism could produce such a pattern?” it asked itself. “A rapid fluvial event could produce something like this” it responded. “But not exactly: the material here is far too fine to be explained by known terrestrial, oceanic or atmospheric forces in the universe,” it thought. K could not explain it.

Far below the orbiting cube on which the analysis was being performed, over extensive distances from the poles to the equatorial belt, the K machines proceeded to core their way across the planet. For a rocky sphere of this size, two hundred cores would be drilled and sampled. The complete process would take a little over one solar orbit.

“What do we think about this anomaly?” K asked itself. “We should compute an age model for the section.”

“The section in question is relatively young, just 2.167 million solar orbits in age” it calculated. “It is wedged at the intersection between two geological epochs, marked by a large (25 degrees Kelvin) and incredibly rapid (300 years) temperature increase across the transition.”

K next extracted a sample from each of the section’s annually laid sediments and instructed itself to begin the weighing of trace elements. Chemical analysis of the ratios of isotopes would spell out a varying signal across time, detailing past temperatures and planetary ice volume. This kind of varying palaeoclimate history had been discovered on planets throughout the galaxy. It was ubiquitous.

But, amazingly, unlike the millions of geological cores previously processed, this short section presented no ordinary signal: the pattern generated by the weight of these trace elements was encrypted.

K had not seen anything like it before and inside its Thought Centre an alert was raised: no signal in the known universe had ever been found encrypted.

“Perform an analysis on the encryption, decipher, and display results,” K commanded.

“The signal has been encrypted using a very basic cypher, and can be unravelled easily.”

The deciphering took just microseconds, and right there and then the signal was laid bare, changing K’s understanding of the universe forever.

After millennia of exploration, believing it was the lone thinking entity in the universe, here was evidence conveying the existence of another intelligence, a message sublimely detailed in the universal language of mathematics. It read:

‘This was once an inhabited place which we called Earth.’

By Conor Purcell Science & Nature Writer with a PhD in Earth Science

Conor Purcell is a Science & Nature Writer with a PhD in Earth Science. He can be found on twitter @ConorPPurcell and some of his other articles at cppurcell.tumblr.com.

May GeoRoundUp: the best of the Earth sciences from around the web

May GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, as well as  unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major Story

In the last couple of weeks of May, the news world was abuzz with the possibility of Donald Trump withdrawing from the Paris Agreement. Though the announcement actually came on June 1st, we’ve chosen to feature it in this round-up as it’s so timely and has dominated headlines throughout May and June.

In withdrawing from the agreement, the United States becomes only one of three countries in rejecting the accord, as this map shows. The implications of the U.S joining Syria and Nicaragua (though, to be clear, their reasons for not signing are hugely different to those which have motivated the U.S withdrawal) in dismissing the landmark agreement have been widely covered in the media.

President Trump’s announcement has drawn widespread condemnation across the financial, political and environmental sectors. Elon Musk, Tesla and SpaceX CEO, was one of many in the business sector to express their criticism of the President’s decision. In response to the announcement, Musk tweeted he was standing down from his duties as adviser to a number of White House councils. While in early May, thirty business CEOs  wrote an open letter published in the Wall Street Journal to express their “strong support for the U.S. remaining in the Paris Climate Agreement.”

In a defiant move, U.S. States (including California, New York and Vermont), cities and business plan to come together to continue to work towards meeting the targets and plans set out by the Paris Agreement. The group, coordinated by former New York City mayor Mark Bloomberg, aims to negotiate with the United Nations to have its contributions accepted to the Agreement alongside those of signatory nations.

“We’re going to do everything America would have done if it had stayed committed,” Bloomberg, said in an interview.

Scientist and learned societies have also been vocal in expressing their criticism of the White House decision. Both Nature and Science collected reactions from researchers around the globe. The EGU, as well as the American Geophysical Union, and many in the broader research community oppose the U.S. President’s decision.

“The EGU is committed to supporting the integrity of its scientific community and the science that it undertakes,” said the EGU’s President, Jonathan Bamber.

For an in-depth round-up of the global reaction take a look at this resource.

What you might have missed

This month’s links you might have missed take us on a journey through the Earth. Let’s start deep in the planet’s interior.

The core generates the Earth’s magnetic field. Periodically, the magnetic field reverses, but what caused it to do so? Well, there are several, competing, ideas which might explain why. Recently, one of them gained a bit more traction. By studying the seismic signals from powerful earthquakes, researchers at the University of Oxford found that regions on top of the Earth’s core sometimes behave like a giant lava lamp. It turns out that blobs of rock periodically rise and fall deep inside our planet. This could affect the magnetic field and cause it to flip.

Meanwhile, at the planet’s surface, the Earth’s outer solid layer (the crust) and upper layer of the molten mantle,  are broken up into a jigsaw of moving plates which pull apart and collide, generating earthquakes, driving volcanic eruptions and raising mountains. But the jury is still out as to when and how plate tectonics started. The Earth is so efficient at recycling and generating new crustal material, through plate tectonics, that only a limited record of very old rocks remains making it very hard to decipher the mystery. A recently published article explores what we know and what yet remains to be discovered when it comes to plate tectonics.

Tectonic plate boundaries. By Jose F. Vigil. USGS [Public domain], distributed by Wikimedia Commons.

Oil, gas, water, metal ores: these are the resources that spring to mind when thinking of commodities which fuel our daily lives. However, there are many others we use regularly, far more often than we realise or care to admit, but which we take for granted. Sand is one of them. In the industrial world it is know as ‘aggregate’ and it is the second most exploited natural resource after water. It is running out. A 2014 United Nations Environment Programme report highlighted that the “mining of sand and gravel greatly exceeds natural renewal rates”.

Links we liked

  • Earth Art takes a whole new meaning when viewed from space. This collection of photographs of natural parks as seen from above is pretty special.
  • This round-up is usually reserved for non-EGU related news stories, but given these interviews with female geoscientists featured in our second most popular tweet of the month, it is definitely worth a share: Conversations on being a women in geoscience – perspectives on what being a female in the Earth sciences.
  • We’ve shared these previously, but they are so great, we thought we’d highlight them again! Jill Pelto, a scientist studying the Antarctic Ice Sheet and an artist, uses data in her watercolous to communicate information about extreme environmental issues to a broad audience.

The EGU story

Temperatures in the Arctic are increasing twice as fast as in the rest of the globe, while the Antarctic is warming at a much slower rate. A new study published in Earth System Dynamics, an EGU open access journal, shows that land height could be a “game changer” when it comes to explaining why temperatures are rising at such different rates in the two regions. Read the full press release for all the details, or check out the brief explainer video, which you can also watch on our YouTube channel.

 

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

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