We know that Arsenic is released into the environment naturally through the weathering and erosion of sulphide minerals. .These sulphide minerals can form soils with very high concentrations of arsenic, and can dissolve in water. An estimated 25% of arsenic emissions into the atmosphere come from natural sources, mostly volcanoes. The majority of the arsenic released ends up in the soil and the ocean.
hello
this link below could help
http://www.miningfacts.org/Environment/What-is-the-role-of-arsenic-in-the-mining-industry/
regards
Gold miners use cyanide to exploit low gold density rocks. They collect cyanide in cyanide lakes around the mines. Once it spills, kills every living organism. https://en.wikipedia.org/wiki/2000_Baia_Mare_cyanide_spill
Dear Dr Robert Istvan Radics
Thank you for sharing your comment and references, hope in every country it would be done completely .
Best regards
Dear my teacher
Arsenic Background
Sources of Arsenic contamination:
mine waste (primarily sulfide, iron and tin)
tanneries
metal smelters
geothermal activity
Arsenic has been used in the following:
embalming fluids
paint pigments
insecticides
herbicides
defoliants
metal alloys
Dear Parisa, before answering your question on arsenic in mining and it's remediation (which we should cover over several posts as it's a large field), I would like to point out some general mining observations.
Regarding mining slime dams failures mentioned, these occur at about twice the rate of normal dam breaks. Biological remediation post closure, may weaken structures not initially designed for it and this encompassing most legacy mine sites. Modern practices are increasingingly incorporating organic content in engineering design for combined extended post mine stability and remedaition. There is a great need for legacy mine site remediation, with an estimated 30,000 large mines worldwide requiring attention. Legacy mines have considerable scope for high impact pollution and urgently require remediation.
A rough 2001 global estimate of annual mine wastes produced such as tilings and waste rock is around 15-20BT (Lottemoser, B. 2006), potential with considerable environmental impact long term. This is accompanied by some 40Mt of metals won. Critics would say the industry is inherently dirty and polluting. Proponents would say this is largely a legacy problem of the past, and lax governments not practicing due care and diligence on closures today. They cite modern mines are required to be well planned, their effects to be predicted, monitored and remediated for safe long term closure. Yet environmental contamination and pollution continue unabated globally as a result of improper mining, smelting and waste disposal. The technology is there to deal with it properly and governments and companies should be forced to adopt best practices. Australia has the highest output of wastes, and the toughest regulations, yet still with some legacy disasters unpremeditated.
In once sense proponents have a point when they argue this mining pales into insignificance compared to the effects of humans themselves on the landscape, now affecting entire countries, even whole continents: urbane coverage alone and its effluents; air, soil, surface water and ocean pollution. Humanities itself is the very cause of human raw material consumption with destruction of soils, habitat, agricultural and forestry, land practice destruction of habitat etc. One human being is essentially a polluting machine! No matter if they are a green twig or not! Yet we intrinsically view soft targets like mining, justified or otherwise to escape our own culpable roles by simply being. Getting on with the job will help. Paul Earlich had it right, the real culprit is overpopulation. Remediation to match relentless growth is unattainable should it continue unabated. Remediation colleagues have an enormous role, provided they are permitted to do so.
Dear Bernhard
Thank you for your comprehensive and brief answer. I really appreciate you.
Best regards
Dear Parisa and Mutasem.
In reality 'Regulated Mining' under strict environmental laws is a luxury of wealthy industrialised nations.
Increasingly 'perceived' transgressions have repercussions from company shareholders. Generally Introduction of environmental laws and regulations has seen massive environmental progress in these countries. 'Social licence to operate' is the big things these days and shareholders don't like it when their investment is terminated by environmental disasters. Nor do inhabitants surrounding the mines who whish to reuse the lands affected once mining is completed, unhindered, and safely.
It is the conduct of some of these companies when they operate in developing countries with lax environmental laws (an now increasingly visa visa as I mention below, a new disturbing trend) that can be problematic. Though increasingly, social licence extends from shareholders to shame their own companies operating overseas.
Mostly though problems occur in unregulated countries.
For instance; Artisanal mining, with uncontrolled release of mine wastes, employs directly and indirectly some 100 Million people and accounts for some 15 to 20 % of all minerals produced worldwide. So this is a significant pollution generating capacity, including mercury used in gold and silver extraction. Increasingly cyanide with primitive ball mills, the effluent simply washed down creeks in SE Asia and elsewhere, sanctioned, often by corruption at exclusion of compliant, licensed capable companies. This is a real challenge for remediation workers and researchers.
Though we get the fact 100 Million people are employed, at the expense of wealthy shareholders. The later also assumes the rest of the country can depend on 'trickle feed economics' from a robust mining economy. This actually works in Australia, even everting recessions of recent times. Though this will only work in context of a developed nation and not so well where artisanal mining is rampant to the levels corporate mining profits are not distributed nationally via corruption and lax laws, taxation avoidance included.
However, in my view, endless mining royalty battles between competing nations for their insatiable bottomless national funding pit should instead be directed towards an international fund to clean up the worlds leading legacy mining disasters, unhindered by national borders, politics or but simply to clean up the world for its inhabitants and ecosystem safety.
From 1946 to 1990, Russia instigated unregulated mining in East Germany and many communist countries still practice it today.
Pollution is not new. It extends back at least 5000 years, even then surprisingly to very large extents in the northern hemisphere at least. Pollution is well documented before the industrial revolution, but really got going in a very big way with invention of the blast furnace and smelting 'advances'.
Mercury has been used for about 3000 years in concentrating gold and silver from geological ores. Not uncommonly one nation would preclude mining and metallurgy due to its dangers. This was the case in italy , were it was banned by the Romans after just 100 years of mining, one assumes due to its dangers. Instead the Romans conducted mining and metallurgy in Spain they controled, using slave labour.
Massive pollution already occurred in the Rio Tinto mines of Spain 5,000 years ago and northern Harz province of Germany. Mining Rio Tinto ores in Spain caused massive metal contamination of stream and estuary sediments since the Copper Age 5000 years ago (Leblanc et al. 2000; Davis et al. 2000 cited in Lottemosser 2003).
Smelting of lead-rich silver ore in Spain by the Romans 2000 years ago quadrupled the levels of lead in the atmosphere as far away as Greenland (Rosman et al. 1997, cited in Lottemoser 2003, 2007). Polution is not new and while implementing regulations and environmental laws has seen massive improvements, particularly where enforced in many developed nations, it continues unabated worldwide.
A disturbing new trend is that companies with a poor environmental track record in their developing nation, flouting their own laws from country of origin, are increasingly invited into developed nations and others even with sound environmental regulations, to conduct operations cheaply. These companies are promoted by politicians promising development for their constituents and naturally their own chances of re-election , but with unknown costs to the environment. Naturally it can be a good if environmentally compliant, but one report suggest the obvious negative potential even in Australia, when: https://www.theguardian.com/business/2017/oct/04/mining-companies-links-with-politicians-susceptible-to-corruption-report
We are still a way of dealing with arsenic, but we will get there, now that we can get the political and social stuff out of the road.
Dear Bernhard
Yes, as you mentioned " Mostly though problems occur in unregulated countries. "
and unfortunately most of mines in many countries are classified as you named them.
Arsenic can be toxic in large doses, and the mining industry monitors and prevents its release into the environment. Air ,mine tailing and wastewater pollution can be controlled effectively by using the following treatment methods(1):
1-arseic air pollution can be controlled by using:
- scrubbers
- electrostatic precipitators
- baghouses in smelters
2-Mine tailings and wastewater can be treated /or filtered with:
- iron oxides
- clay liners
-activated charcoal filters
1-http://www.miningfacts.org/Environment/What-is-the-role-of-arsenic-in-the-mining-industry/
Dear Dr Hassan Alshamsi
Thank you for sharing your answer in the group. I appreciate you.
Best regards
Mine Remediation Continued:
Each mines has unique geology, mineralogy, ecology, climate, topography, hydrology, landscape. and stability, and a suite of exploited metals, metalloids or industrial minerals. There is a need to understand these in detail along with the composition, properties, behaviour and impacts of wastes. Geo-metallurgical investigations during feasibility studies help initial investigations for mine planning and remediation sequencing. It is a unique exercise in design to remediate for stability into 'perpetuity' on mine closure since little ongoing remediation afterwards is the norm. Operations involve revegetation and landform contouring and on closure, removal of structures and facilities, sealing and securing workings. Tasks include:
o Construct long-term stable waste repositories: tailings to prevent migration of and contaminating environment
o Waste and mine surface leach characterisation for acid generation and element leaching
o Predict water quality and quantity in pits and pit lakes /lakes on closure and flows through mine voids on flooding or open to oxidation. Hydrology and meteoric studies.
o Water quality monitoring and prediction of underground working lactates to aquifers and deep saline ground waters ingress from deep working to shallow aquifers.
o Final landforms construction; secure waste rock dumps and tailings to resist wind and water erosion, along with site
o drainage, remodelling surrounding landform.
o Sulphide wastes are dumped in such a way to avoid grading which allows oxidation via air convection, advection and drainage. Acid mine waters or cyanide bearing waters treated.
o Increasingly Technosol constructs: (artificial soil constructs from wastes) as for soil shortages and bare ground coverage is required by selective waste handling for sub grades to minimise salts, metals, metalloids, and acid generating species.
This stage could adopt phytoremediation protocols and organics via waste food, forestry of fisheries resources for carbon and essential P, N, K, to build structure and water holding capacity which is poor in wastes.
o Vegetation cover: Design plan growth medium for waste cover revegetation; Final dressing with endemic plants and soil, and or agricultural species.
Acid Mine Drainage (AMD)
Metallic, phosphate, coal, oil shale and mineral sands ores have potential to oxidize sulphides from acids generating species in structures including: stockpiles, waste rock and tailings repositories, exposed mine surface prone to oxidation and exposure to oxygen, meteoric and ground water. The acids leach metals and metalloids into the environment. AMD onset can be rapid and hard to stop once started ,evidenced by iron stains and low pH. However metal leaching can also occur in neutral to alkaline waters. Point leaching sources and environmental escape include:
o Underground working in elevated positions or above water table with mine waters escaping through rock fractures or surface openings at lower hydraulic levels into surface seep runoff or and ground waters plumes;
o Ground and meteoric waters enters pits and mine working surfaces and open cut excavations;
o Supernatant tailing pond escape to rock fracture systems bypassing tailing Dam seepage recovery pounds;
o Precipitation and flooding of tailing disposal facilities without adequate drainage protection, recycling and downstream holding pounds;
o Rainfall interacting with mineral process and metallurgical processes and mining;
o Surface water and pore fluids of tailings, heap leach piles, coal spoil heaps and waste dumps surfacing as seep waters that migrate into ground water aquifers;
o Controlled and uncontrolled discharge of process water from tailings dams, lean ore stacks, ponds, heap leach piles, conveyor, loading barge and transport piles.
o Construct long-term stable waste repositories: Â tailings to prevent migration of and contaminating environment
o Waste and mine surface leach characterisation for acid generation and element leaching
o Predict water quality and quantity in pits and pit lakes /lakes on closure and flows through mine voids on flooding or open to oxidation. Hydrology and meteoric studies.
o Water quality monitoring and prediction of underground working lactates to aquifers and deep saline ground waters ingress from deep working to shallow aquifers.
o Final landforms construction; secure waste rock dumps and tailings to resist wind and water erosion, along with site
o drainage, remodelling surrounding landform.
o Sulphide wastes are dumped in such a way to avoid grading allowing oxidation via air convection, advection and drainage. Acid mine waters or cyanide bearing waters treated.
o Increasingly Technosol constructs: (artificial soil constructs from wastes) as constructs for soil shortages and bare ground coverage by selective, waste handling for sub grades  to minimise  salts, metals, metalloids, acid generating species. This stage could adopt phytoremediation protocols and organics via waste food, forestry of fisheries resources for carbon and essential  P  N, K, to build structure and water holding capacity which is poor in wastes.
o Vegetation cover: Design plan growth medium for waste cover  revegetation; Final dressing with endemic plants soil and or agricultural species.
  AMD
Metallic, phosphate, coal, oil shale and mineral sands ores have potential to oxidize sulphides and acids generating species from, stockpiles, waste rock and tailings repositories, exposed mine surface prone to oxidation on exposure to oxygen and  meteoric and ground water, the acids leaching metals and metalloids into the environment.   AMD onset can be rapid and hard to stop once started ,evidenced by iron stains and low pH.  Point leaching sources and environmental escape include:
o Underground working in elevated positions or above water table with mine waters escaping through rock fractures or surface openings at lower hydraulic levels into surface seep runoff or and ground waters plumes;
o Ground and meteoric waters enters pits and mine working surfaces and open cut excavations;
o Supernatant tailing pond escape to rock  fracture systems bypassing tailing Dam seepage recovery pounds;
o Precipitation and flooding of tailing disposal facilities without adequate drainage protection, recycling and downstream holding pounds;
o Rainfall interacting with mineral process and metallurgical processes and mining;
o Surface water and pore fluids of tailings, heap leach piles, coal spoil heaps and waste dumps surfacing as seep waters that migrate into ground water aquifers;
o Controlled and uncontrolled discharge of process water from tilings dams, lean ore stacks, ponds, heap leach piles, conveyor, loading barge and transport piles.
Dear Dr Bernhard
You teach us every point of geology and mineralogy, I learn a ot from you, thank you for taking time for me and other friends, I deeply appreciate you.
Best regards
Dear @Parisa: Mine Remediation Continued:
Each mines has unique geology, mineralogy, ecology, climate, topography, hydrology, landscape and stability and suite of exploited metals, metalloids or industrial minerals. Understand the composition, properties, behaviour and impacts of wastes is a unique exercise for each mine to design a remediation sequence. Stability into 'perpetuity on closure is designed since little ongoing remediation is the norm. Mining operations integrate revegetation landform contouring. On closure structures and facilities are removed, workings are sealed and secured. Tasks include:
o Construct long-term stable waste repositories: tailings to prevent migration of contaminant to environment
o Waste and mine surface leach characterisation for acid generation and element leaching
o Predict water quality and quantity in pits and pit lakes / lakes on closure and flows through mine voids on flooding or open to oxidation. Hydrology and meteoric studies.
o Water quality monitoring and prediction of underground workings leachates to aquifers and deep saline ground waters ingress to deep workings and migration into shallow aquifers.
o Final landforms construction; secure waste rock dumps and tailings to resist wind and water erosion;
o drainage, remodelling surrounding landform.
o Sulphide wastes are dumped in such a way to avoid grading allowing oxidation via air convection, advection and drainage. Acid mine waters or cyanide bearing waters treated.
o Increasingly Technosol constructs: (artificial soil constructs from wastes) as constructs for soil shortages and bare ground coverage by selective, waste handling for sub grades to minimise salts, metals, metalloids, acid generating species.
This stage could adopt phytoremediation protocols and organics via waste food, forestry, fisheries resources for carbon and essential P N, K, to build structure and water holding capacity which is poor in wastes.
o Vegetation cover: plan growth medium for waste cover revegetation; Final dressing with endemic plants soil and or agricultural species.
AMD
Metallic, phosphate, coal, oil shale and mineral sands ores have potential to oxidize sulphides from acids generating species in stockpiles, waste rock and tailings repositories, exposed mine surface prone to oxidation on exposure to oxygen and meteoric and ground water. Acids leach metals and metalloids into the environment. AMD onset can be rapid and hard to stop once started , evidenced by iron stains and low pH. However neutral to alkaline waters also carry appreciable metals, metalloids and other elements. Point leaching sources and environmental escape include:
o Underground working in elevated positions or above water table with mine waters escaping through rock fractures or surface openings at lower hydraulic levels into surface seep runoff or and ground water plumes;
o Ground and meteoric waters entering pits and mine working surfaces and open cut excavations;
o Supernatant tailing pond escape to rock fracture systems bypassing tailing dam seepage recovery pounds;
o Precipitation and flooding of tailing disposal facilities without adequate drainage protection, recycling and downstream holding pounds;
o Rainfall interacting with mineral process and metallurgical processes and mining;
o Surface water and pore fluids of tailings, heap leach piles, coal spoil heaps and waste dumps surfacing as seep waters that migrate into ground water aquifers;
o Controlled and uncontrolled discharge of process water from tilings dams, lean ore stacks, ponds, heap leach piles, conveyor, loading barge and transport piles.
Cover arsenic specifics next
Dear Maryam, yes, agree, it would be great indeed. There is much potential for improvement in biologics RE arsenic and the group is encouraged to make contributions. Currently biologics are partially integrated; including the bacterial tailings pond etc, but there is scope for much more integration. As aforementioned: arsenical dust, metallurgical efficiencies, electromechanically containment, concrete spraying of Adits and Shafts to stop oxidation, waste engineering structures etc, are all essential and important first steps to get metal "loadings" down. Nevertheless, biological approaches are improving and will extend the efficiencies in several ways to decrease arsenic ingress to biota, decrease overall metal toxicities, particularly in remediated and mine environment management phases. Indeed we are working on it ourselves. The question is where and how to apply it in the mine environment? In this quest it's as well we first overview arsenic in different sectors of the mine environment geochemistry, it's competing toxicities with other metals from source, the operationally "ameliorated" and "remediated" environment to stop arsenic "running" to see improvements. Phytoremediation has a potentially large role here for arsenic.
Dear Bernhard
Yes phytoremediation is one of the best method and we are working hard on this issue by some especial plants and also using the waste of food and fruits in order to improve the removal conditions.
Best regards
Thank you Dear Parisa . We normally think of phytoremediation as an end stage activity at levels of revegetation in remediation of mines. Understandably; excessive metal/metalloids results in soil quality degradation, crop yield reduction, toxicities, general pollution of our waterways. But these metal loadings could be abrogated further, by paying phytoremediation attention in the active mine environment ie earlier. And naturally the disasters of legacy mines post mining. This opens up a raft of potential phytoremediation research, for example: The internal structure of mine wastes to slow down AMD, modulate and fix arsenic in different oxidative-pH- heat conditions; alter the bacterial milieu involved in AMD or neutral water arsenic loadings. Some have tried bactericides, phage-virus, but resistance toxicities etc. suggest early stage alternative intervention in waste heaps including phytoremediation in limiting Fe3+ oxidants for pyrite etc., may be more productive research. Other earlier interventions could involve the metallurgical plant and active mine drainage; constructs of artificial soil from wastes, such as Technosol/phytoremediation as a foundation sub grade to cover bear ground prior to waste and soil cover, as a metal trap to ground/seep waters. Soil is often in short supply in the mine environment. Remediation of legacy mines, is a large domain in itself for phytoremediation, as aforementioned 30,000 large mines worldwide, and about 50,000 arsenical legacy sheep dips in New Zealand, let alone worldwide, with industrial sites. Here vast soilless expanses occur that could benefit from Technosol-phytoremediation. These are man made soils using wastes that have large potentials to integrate what your forum is all about; Wastes of agricultural, food processing, forestry, fisheries, industrial and mining wastes.
Your latest efforts Parisa on arsenic are particularly appreciated. I look forward to it, and the groups general contributions on arsenic, for which there are generally no safe lower limits and less is best.
When dealing with arsenic in the environment the relation of sulfide mining and As hazards is quite evident and industry must provide (known) methods to prevent the risks. However, the less obvious threat of As release hidden in oxidizing environment is of concern likewise, the more so as it is much more challenging to handle. Fe-oxide-hydroxides (Fe-ox-hyd) are very efficient in scavenging As by coprecipitation, adsorption processes and, finally, immobilization by the formation of very stable Fe-As compounds (e.g. the mineral scorodite). Arsenic concentrations in geological strata containing Fe-ox-hyd are generally high (e.g. SW Germany, Jurassic: P50 – 36 ppm, P90 – 101 ppm) and can reach values up to > 1100 ppm (even higher values are reported from other Fe-ox-hyd deposits). Therefore, the huge dimensioned sediment series of Fe-ox-hyd bear a long standing potential of As hazards. Depending on the environmental conditions Fe-ox-hyd can behave as sink or source for arsenic (and other elements (e.g. heavy metals)) and the response of Fe-ox-hyd to changing environmental conditions in soils and sediments is one of the predominant concerns of As hazards also in regions poor in sulfides. Due to the large solid/solution ratio in sediments small changes of conditions can cause weakening of As bondings and result in high As concentrations in ground waters. Engineering management activities in these areas (e.g. ground works, excavation dumping, ground water extraction and flow management, mining) have to consider the sensitivity of response to shifts of environmental conditions by man-made interferences. Operations changing the pristine conditions are fraught with the risk to cause environmental hazards also in these areas. A comprising overview of As regarding these aspects is given by e.g. Smedley and Kinniburgh (2002; https://doi.org/10.1016/S0883-2927(02)00018-5); an insight on stabilities of As in the presence of Fe can be found e.g. at Lu & Zhu (2011; DOI: 10.1007/s12665-010-0652-x).
Thank's Dieter, for a helpful contribution. For the mine environment generally for As in relation to other metals/metalloids , I would also recommend the text by Bernd Lottemoser: "Mine Wastes, Characterization, Treatment and Environmental Impacts": This covers both AMD and neutral and alkaline mine waters and diverse settings, secondary minerals, resorption and amelioration. The AMD conference proceedings and the workshop are useful in practice across the resource cycle. The 9th was held in Burnie, Tasmania.
- Badges
- Science topic