Wednesday, September 2, 2015

The Monks of the Mines

The following is an edited excerpt from an article in the Sept. 2015 issue of the National Geographic. Being unable to add value to a fine article, I decided to simply publicize the story.

Full article and photos can be found here
Author: Hannah Bloch
Photographer: Simon Norfolk

Under threat of Taliban attack, archaeologists are excavating a spectacular Buddhist complex before it’s obliterated by a huge mining operation.

It is in a district of Logar Province friendly to the Taliban, subject to roadside bombs, intermittent rocket attacks, kidnappings, and murders that a team of Afghan and international archaeologists, supported by up to 650 laborers, has, over the past seven years,  uncovered thousands of Buddhist statues, manuscripts, coins, and holy monuments. Entire monasteries and fortifications have come to light, dating back as far as the third century A.D. More than a hundred check posts surround the site, which is patrolled day and night by some 1,700 police.
The excavation is by far the most ambitious in Afghanistan’s history. But the security wasn’t put in place just to protect a few scientists and some local workers. Buried below the ancient ruins is a lode of copper ore that extends two and a half miles across and runs a mile or more into the Baba Wali mountain, which dominates the site. It ranks as one of the world’s largest untapped deposits, containing an estimated 12.5 million tons of copper. In antiquity, copper made the Buddhist monks here wealthy; colossal deposits of purple, blue, and green slag, the solidified residue from their smelting, spill down the slopes of Baba Wali, attesting to production on a nearly industrial scale. The Afghan government hopes that copper will help make the country wealthy again, or at least self-sufficient.
In 2007 the Beijing-based China Metallurgical Group Corporation (MCC), leading a state-backed consortium, won rights to extract the copper here on a 30-year lease. (China is ravenous for copper: It now consumes half the world’s supply.) The company made a bid worth more than three billion dollars and promised to provide infrastructure for this isolated, underdeveloped district, including roads, a railway, and a 400-megawatt electricity plant. Afghan officials estimated that the mine would provide a $1.2 billion infusion into the country’s fragile economy, dependent since 2002 on foreign assistance and now facing a seven-billion-dollar annual deficit.
Mes Aynak’s archaeological potential has been known for decades. But the artifacts were already in danger: not from destruction by the Taliban, but from being plucked out piecemeal by looters, lost to science. “If it will not be destroyed by mining, it will be destroyed by looting,” says French archaeologist Philippe Marquis, who directed excavations at the site from 2009 to 2014. Better, he says, to document as much as possible now in a systematic way.
Despite the heavy security, present-day dangers have delayed the mine’s development. The blue-roofed compound, built for Chinese engineers, was abandoned after a series of rocket attacks in 2012 and 2013. Land mines left behind by the Soviets in the 1980s and explosive devices left more recently by the Taliban and al Qaeda pose yet another danger, and eight mine-clearing specialists were killed by the Taliban in 2014. 
Add to the security challenges the logistical complications—the lack of a railway to transport the copper out of the region and a serious scarcity of water—and it’s no surprise that mining, originally projected to start in 2012, has not yet commenced. In 2013 the MCC began to back off from some terms of its contract, and the two sides have yet to renegotiate the agreement. It’s unlikely that any extraction will take place before 2018, if then.
In a Troubled Region, a Harmonious Past
The delays have given archaeologists considerably more time to excavate than they had expected, though with a greatly reduced workforce. The past they’re revealing presents a stark contrast to the violence and disorder of their own time. From the third to the eighth centuries A.D., Mes Aynak was a spiritual hub that flourished in relative peace. At least seven multistory Buddhist monastery complexes, containing chapels, monks’ quarters, and other rooms, form an arc around the site, each protected by ancient watchtowers and high walls. Within these fortified complexes and residences the archaeologists have uncovered nearly a hundred schist and clay stupas, Buddhist reliquaries that were central to worship. 
Mes Aynak was also a key economic center in Gandhara, a region spanning what’s now eastern Afghanistan and northwestern Pakistan. Gandhara was a civilizational crossroads, a place where the great religions of Hinduism, Buddhism, and Zoroastrianism met and where ancient Greek, Persian, Central Asian, and Indian cultures melded. It was the “center of the world,” in the words of Abdul Qadir Temory, the lead Afghan archaeologist on the project.
Gandharan Buddhists were among the first artists in the world to depict the Buddha in realistic, human form—a Hellenistic innovation from the days of Alexander the Great, who first marched through Afghanistan in 330 B.C. At Mes Aynak chapels have been uncovered with double-life-size Buddha statues still bearing traces of their red, blue, yellow, and orange painted robes; caches of gold jewelry; fragments of ancient manuscripts; and walls adorned with frescoes. One niche yielded a schist statue featuring a rare depiction of Siddhartha Gautama before he became the Buddha.
Cascades of copper coins from the third to seventh centuries A.D. have also spilled from the site, collected from the floors of dwellings and from where they had been carefully cached by the hundreds. Many bear the image of the second-century Kushan ruler Kanishka the Great. He may or may not have practiced Buddhism—but he welcomed it and other religious traditions in his empire, notably fire-worshipping Zoroastrianism, which originated in ancient Persia. Many of the coins found at Mes Aynak depict Kanishka on one side and either a seated Buddha or a Persian deity, such as Ardokhsha, a goddess of fortune, on the other.
Though much is known about ancient Buddhism’s links to trade and commerce, little is known about its relationship to industrial production. This is where Mes Aynak may be able to fill in important blanks, hinting at a more complex Buddhist economic system than has been previously understood. Unlike the far better known Bamian—an ancient Buddhist pilgrimage site and Silk Road caravan center 125 miles to the northwest, formerly home to two colossal, sixth-century Buddha statues carved out of a cliff face, blasted to rubble by the Taliban in 2001—Mes Aynak seems to have thrived primarily because it was a copper extraction and production hub, a Pittsburgh to Bamian’s New York. The sacred monastic complexes are right on top of the copper ore.“Kanishka’s coinage was valued from Rome to China,” says longtime Kabul residentNancy Hatch Dupree, 87, the U.S.-born grande dame of Afghan heritage scholars. 
“I do not know of any other site where monasteries coexisted in perfect [symbiosis] with production or industrial centers,” says Zemaryalai Tarzi, an Afghan archaeologist who first visited Mes Aynak with a French team in 1973. “These kinds of tight relationships between Buddhist monasteries and the industrial or commercial exploiters of natural resources have no precedent.”
An Abundance of Riches
Puzzling out the full meaning of Mes Aynak will require decades—and a new generation of archaeologists. After earning his degree at Kabul University, Sultan Masoud Muradi, 24, the son of a Kabul construction worker, competed to take part in excavations at the site. He’s proud that he and his colleagues represent different ethnicities and work easily together—no small matter in a country riven in the 1990s by a horrific civil war among mujahideen groups divided along ethnic lines. “We have 5,000 years of history, and for Afghanistan’s new generation, it’s very important to know about it,” he says, holding a small shovel while taking a break from digging. “Otherwise we are just famous for terrorism and poppy production.”
Mes Aynak’s landscape is completely deforested today, and it’s possible that ancient copper smelting played a role in the area’s denuding—which in turn may have ended copper production. Huge quantities of wood had to be burned to make charcoal, and up to 20 pounds of charcoal could be required to extract a single pound of copper from ore. Enough was needed to heat a fire to almost 2,000 degrees Fahrenheit and keep a small furnace roaring up to several days.
Processing so much copper also required a reliable water supply to wash the ore and quench white-hot ingots. That water probably came from mountain springs, shallow streams, and ancient underground irrigation channels called karez, which are still used in parts of Afghanistan. One 30-foot-long karez has been excavated in the northern section of the site, probably part of a network of such channels. The ongoing deforestation could have reduced the area’s rainfall, making water even scarcer.
A paucity of water remains a concern in this drought-prone region, and a major obstacle to future mining. Integrity Watch Afghanistan, a Kabul think tank, reported in 2013 that villagers around Mes Aynak complained that the water table dropped by more than six feet after preliminary drilling. “When copper production starts, it will require seven million liters in one eight-hour shift,” says Javed Noorani, who authored the Integrity Watch report. “The area is already water deficient.”
The archaeologists must cope with a problem not of scarcity but of overabundance: The rate at which the excavation has proceeded risks outpacing the ability to store and protect everything coming out of the ground. “Excavation is easy,” says Omar Sultan, Afghanistan’s former deputy culture minister and a Greek-trained archaeologist. “Safeguarding is the hard thing to do.”
More than a thousand of the most important pieces have gone straight to theNational Museum of Afghanistan in Kabul. “Unfortunately we cannot accept all the artifacts,” says Omara Khan Massoudi, for many years the director of the museum. “There is no place for them.”
But first Afghanistan’s security challenges must be resolved. And in the long term more mining delays could pose more dire threats. Mes Aynak’s security depends in large part on ensuring that local men, vulnerable to the lure or coercion of the Taliban, stay gainfully employed. Many resent having been displaced from their villages to make way for the copper mine. The World Bank, which has been supporting the archaeological work through a project with Afghanistan’s Ministry of Mines and Petroleum, estimates that the mine will eventually provide 4,500 direct jobs and many more thousands of indirect ones, though there’s growing skepticism that the jobs will ever materialize.
Over the years a few hundred men have been paid generously by local standards to wield pickaxes and shovels or do other menial work at the archaeological site. But “if you have no food or salary, when your children are hungry, you’ll do anything,” says Habib Rahman. “Maybe join the Taliban. They pay a salary.” In 2001 the gray-bearded, 42-year-old father lost a leg to a land mine while herding goats. Now he walks with the aid of crutches two hours each way from his mountain village to wash pottery sherds at Mes Aynak.
The hardscrabble lives of locals like Rahman are not likely to change much in the immediate future. Many are ambivalent about the rich history they’re helping reveal, feeling no personal ties to a pre-Islamic past. It doesn’t help that the Taliban have threatened some workers, accusing them of promoting Buddhism. Still, there’s admiration for the achievements of the past. “My forefathers were Muslim,” says one 36-year-old laborer and Afghan Army veteran who gave his name only as Javed. “But we know a lot of generations passed through this ground. When I am working, I am thinking that here was a civilization, a factory, a city, kings here. Yes, this is Afghanistan also.”

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Thursday, March 12, 2015

Mining & Economic Sustainability

This post is an excerpt from a very good publication by Roderick Eggert of the Colorado School of Mines, exploring how mining can contribute to long term and sustainable economic development. Sorry for the lack of pictures and some dryness but the content is well worth going through.

The full publication can be accessed here:

What are the economic effects of mining? It is too easy and simple to take an extreme position--either that minerals are a curse to be avoided because of their negative economic, environmental, or social effects on local communities or national economies, or--alternatively--that minerals are a blessing that hold a key to economic development in mineral-rich regions.

The reality is more complicated. Minerals in the ground are potential wealth. They have the potential to contribute significantly to the economic development of communities and nations. Mining can create significant economic benefits--the direct benefits that come in the form of income and employment, as well as the indirect benefits that come in the form of local or national purchase of mining inputs, local or national processing of mineral ores and concentrates, and the additional spending by mining households that stimulates local economic activity generally. Mining can persist in communities and regions even as the physical quality of mineral deposits declines because of the advantages to a community that come in the form of infrastructure and agglomeration economies.

But these benefits often come at a cost. At the local level, mining affects the natural environment (some of which, to be sure, is avoidable at a cost) and often creates significant social disruptions. At the national level, mining requires that governments and other entities learn how to: live with market instability, deal with structural changes in the economy due an expanding or booming resource sector, and minimize rent-seeking and other political problems caused by the presence of mineral rents. The national economies dependent on mining are diverse--geographically and in terms of per capita income, life expectancy, and adult literacy. They include some of the poorest nations on earth and a number that have performed very poorly over the last several decades.

Whether the benefits of mining outweigh the costs is specific to a community or nation. How mining and mineral wealth are managed--by governments, mining companies, and civil society--is critical to whether the potential embodied in minerals in the ground is realized.

Can we manage mineral wealth so that the economic benefits are enhanced in the short term and sustained over the long term? Yes, but to do so we must address four challenges.

The first is the Creation Challenge--that mineral wealth be created in the first place, efficiently and in a manner consistent with social preferences for environmental quality and other social and cultural values. Governments play a critical facilitating role in meeting this challenge, through the legal and political framework in which actual mineral exploration and mine development occur. The policy framework generally should be nondistortionary in the sense that it does not steer or guide investment toward particular sectors but rather facilitates investment in those sectors with the greatest commercial attractiveness; the major exception to this generalization is when there are spillover benefits to the economy as a whole that are not considered by private decision makers. Although not a panacea, the economic method of benefit-cost analysis provides a useful framework for organizing discussions and making decisions about mineral development. The relevant benefits and costs here include the full social benefits and costs of mineral development. Social costs include the value of environmental damage and social disruptions caused by mining; these costs need to be paid (i.e., those bearing these costs need to be compensated) or else the policy environment of mineral development will not be truly nondistortionary.

Three additional issues are important in addressing the Creation Challenge. First, governments influence perceptions of geologic potential upon which mining companies base investment decisions in mineral exploration and mine development. The availability of basic geologic information is critical in this regard, either through government-funded geological surveys or some other form of public investment or subsidy to the private sector. Second, tax and fiscal systems influence where mineral investment occurs. Third, and perhaps most important, social preferences for environmental quality and other social and cultural values need to be incorporated into decision making about whether a mineral deposit is developed. Ideally, a process through which these preferences are elicited would be part of public policy toward the mineral sector. But in some cases, government institutions are sufficiently weak or ineffective that mining companies and civil society need to assume responsibility for incorporating these preferences into decision making.

The second challenge is the Distribution Challenge--that mineral wealth, once created, be distributed fairly or equitably among private mining companies, government at all levels, and other organizations and entities. To make a long story short, there are no simple rules here, and we should not expect any. There is no single "correct" allocation of the rents. This is a particularly thorny or vexing issue precisely because there are no universally accepted definitions of what is equitable or fair. An important part of this challenge, therefore, is philosophical, defining what is fair. One possibility is to distribute the rents from mineral production in proportion to a party's contribution to mineral development. Even if one agrees with this principle, it often is difficult to specify exactly what each party's contribution is. Another possibility is to distribute mineral rents such that they create the greatest good for the greatest number, or in other words to maximize the total welfare of all interested parties. But again, quantifying where the greatest good will occur is not simple or straightforward. Finally, mineral rents could be distributed such that the least well-off group in society is made as well off as possible. At a practical level, distributions that are considered to be fair or equitable are the result mechanisms and institutional arrangements that facilitate discussion of the following six questions among all interested parties to mineral development (after Young, 1994): (1) what form should the allocation take, (2) what are the eligibility criteria, (3) what counts in the distribution and what are the relevant principles, (4) what are the relent precedents, (5) how should competing principles and criteria be reconciled, and (6) what incentives does a rule create?

The third challenge is the Macroeconomic and Political Challenge--to understand and manage the broader economic and political effects of mineral development. Governments have the primary responsibility for meeting this challenge, much of which is simply sound macroeconomic management. Meeting this challenge involves a number of issues:

     • Responding to at times declining and unstable mineral prices: There is little government
       can or should do to influence prices. Perhaps the biggest challenge here is how to
       respond to significant annual fluctuations in export earnings and government revenues.
       The evidence suggests that a prudent course of action involves: using conservative
       forecasts of mineral revenues, striving for stable growth in government spending in the
       face of unstable mineral prices, and separating mineral revenues from other revenues
       and releasing them for spending at a steady rate (Daniel, 1992).

     • Responding to internal changes in the structure of a national economy as the mineral
       sector expands: Generally speaking, governments should accept the structural change as
       part of the cost of benefiting from increased mineral revenues. If government wants to
       ease the transition, then it can use some of the mineral rents to compensate those
       affected by structural change. Although there are a few situations in which government
       might want to nullify the structural consequences of an expanding mineral sector, in
       most cases actions to nullify the structural adjustment make an economy less flexible to
       changing economic circumstances and less open to international trade, which over the
       longer term impede economic growth.

    • Responding to the political problems often associated with mineral dependence, such as                                    rent-seeking behavior and corruption: Ascher (1999) has three recommendations. First,
       that societies rely on private (non-governmental) development of mineral resources, but
       within a framework established by government. Private companies usually are more
       open to public scrutiny than government agencies, reducing the likelihood of secret
       arrangements, lack of accountability, and corruption. Second, that government
       institutions and their governing rules be restructured: to simplify and clarify mandates
       and jurisdictions of agencies and policies; to use the central budget to clarify priorities;
       and to reform arrangements between government agencies and state enterprises. Third,
       that societies rely on extra-governmental entities (i.e., civil society) to serve as
       ombudsmen or watchdogs to ferret out government mis-management of natural

The final challenge is the Investment Challenge--to ensure that the economic benefits of
mining are sustained, even as a mine is inevitably depleted, by saving a portion of the
revenues from mining and investing them in other forms of capital. This challenge, in other
words, is one of making the mineral wealth permanent. The critical issues here involve

    • How much to save and invest? The answer to this question depends primarily on the
      goal to be pursued and that rate of return on specific investments. The goal of simply
      sustaining the current level of well being requires a lower saving rate than the more
      ambitious goal of increasing this level. The higher the rate of return, the lower the
      necessary saving rate. "Return" here represents the full social return to investments that
      influence the level of human well being (including expenditures on environmental
      quality, education, and human health), and not just the private return on commercial

   • Who should invest the rents from mineral production? Private mining companies are
      likely to be efficient in investing in the sustaining of mineral exploration and
      development; in fact, if the Hotelling or scarcity rents from mineral production do not
       accrue to mining companies, these companies are not likely to invest in mineral
       production in the first place. Other investments, however, have benefits that are diffuse
       or far in the future, implying that private companies are likely to under-invest in these
       activities from the perspective of society as a whole. Government has a central role in
       ensuring that these investments in public goods take place--in basic geological
       information, physical infrastructure, education, and human health. Civil society needs
       to be active in ensuring that governments in fact make these investments.

    • In what should the mineral rents be invested? The basic choice here is between assets
       that yield a visible financial return (e.g., stock, bonds, real estate, directly productive
       enterprises) and assets with less-visible returns (e.g., education, health care, physical
       infrastructure). Most analysts believe investments in directly productive enterprises are
       best left to the private sector. Although diversifying a mineral economy is a laudable
       goal, governments do best when they use rents to facilitate, rather than directly fund,
       investment in directly productive activities outside of mining. Governments do this by
       investing in those assets with less-visible returns, such as education. An important
       caution is that investments of this type are hard to evaluate, precisely because their
       returns are less visible or measurable.

    • Where should the mineral rents be invested? In the mining community itself?
       Somewhere else in the national economy? Abroad? Hannesson (2001) suggests three
       considerations here. First, the larger the economy, the more likely it is that there will be
       productive investments within the economy (and vice versa). Second, the lower the
       level of an economy's development, the more urgent the needs for and returns to
       investments in education and human health; however, the lower level of development,
       the lower the capacity of the economy to absorb investment flows. Finally, the larger an
       economy's dependence on mineral production, the larger the need for internal
       investment of one form or another.


Thus, through appropriate responses to the challenges of mining and economic development, the benefits of mining can be sustained, even when a mine or a mining community inevitably declines as the ore runs out. Mineral wealth lives on, but in other forms--in educated and healthy people, efficient and fair social institutions, and man-made physical capital. To be sure, mining and minerals can be a curse if the challenges are not met. But if we choose not to address the challenges and instead leave minerals in the ground, we forego the opportunity to take advantage of this gift of nature.

Thursday, December 18, 2014

Gold mining in northern Canada

After talking much about artisanal gold mining in Senegal and historical mining in Bolivia, both of which involve mercury amalgamation in ore processing, here is some info on some of the legacies of industrial gold mining in Canada, as it happened at Giant mine.

The iconic C shaft of Giant mine.

Giant mine is an underground mine a few kilometres outside Yellowknife in the Northwest Territories. It started operations in 1949 and ended major operations in 1999. During the 50 years of operations, it produced over 7 million ounces of gold, making it one of the most productive gold mines in Canadian history. However, the large majority of the gold mineralization was refractory (i.e. hard to recover by traditional methods) as the gold was encapsulated in arsenopyrite minerals. Thence, in order to recover gold, the additional step of roasting was necessary, a process that oxidizes arsenopyrite to transform it into iron oxides, arsenic trioxide and sulphur dioxide:

2FeAsS + 5O2 = Fe2O3 + As2O3 + 2SO2

The iron oxides (maghemite and hematite) would retain the gold and be processed through cyanide leaching, but the arsenic trioxide and sulphur dioxide would escape straight out the roaster stack.

While sulphur dioxide emissions is the main industrial contributor to acid rain, the largest concern with this process would have to be the production of arsenic trioxide. It is one of the most toxic forms of arsenic, a mere few grams of which can kill a human adult at once!

Surprisingly, the creation and release of arsenic trioxide in the environment was not considered in the mine development plans. So during the first two years of operations, arsenic trioxide was let to vent out of the roaster with no recovery mechanisms, resulting in the emissions of over 7 tonnes per day of arsenic trioxide directly into the air.

Arsenic trioxide emissions from the Giant mine roaster (Wrye, 2008). tpd stands for tonnes per day.
The first collection of arsenic trioxide started in 1951, though at first did not prove very efficient. After trying a variety of technologies, it was in 1959 that arsenic trioxide recovery became effective. By the time the mine shut down in 1999, a total of 20,000 tonnes of arsenic had been emitted and spread in the local environment.

The smoke coming out of the stack is mainly arsenic trioxide dust.

These 20,000 tonnes, however, represent only about 8% of all the arsenic trioxide ever produced at Giant mine, the other 92%, or 237,000 tonnes, were captured by precipitators and were stored in select underground mine chambers.

A schematic diagram of arsenic trioxide dust management from 1951-1999.

These chambers were originally selected because they were within permafrost areas. However, five decades of mining altered the geothermal gradient and none of these chambers are now frozen, which is a real problem since arsenic trioxide is soluble in water. Therefore, without prompt action, we could see 237,000 tonnes of arsenic trioxide dissolving and dispersing in the surrounding groundwaters.

Biomats found on bulkheads of paste backfills in Giant mine. These biomats are made of arsenite oxidizing bacteria, feeding on the high concentrations of arsenic in the leaching waters.
The last company to own Giant mine went under receivership, such that the federal government is now liable for mine closure. Faced with so large environmental risks, the federal government has implemented a large and expensive remediation plan which is currently underway. This project involves installing cold pumps in order to freeze the arsenic trioxide chambers, building a new water treatment treating facility to treat contaminated surface and ground waters, covering tailings ponds, removing contaminated soils and demolishing contaminated buildings.

The first storage chamber successfully frozen.
Thus far the first of twelve underground chambers has been successfully frozen. Also, the most contaminated buildings (namely the roaster complex) have been demolished, and contaminated materials are waiting to be stored underground.

The roaster complex was bagged to avoid spreading contaminated dust during demolition .
Demolishing the roaster
Contaminated building materials are stored in ship containers.
Ship container are stored next to tailings ponds, waiting permanent storage in underground chambers.

The remediation plan is estimated to cost $900 Million, paid for by the Canadian tax payer. It is a complex and comprehensive plan that manages the most pressing issues, avoiding the tragic release of hundreds of thousands of tonnes of arsenic in the environment, and cleaning up a very large portion of the mine property. However, the freezing system and the planned water treatment plant will require maintenance in perpetuity, a cost and burden bequeathed to generations yet unborn.

Furthermore, no one knows how the frozen chambers will fare with an increasingly retreating permafrost and the effects of climate change being felt very seriously in these latitudes.

The remediation plan also does not include cleaning up contaminated areas beyond the mine property. The 20,000 tonnes of arsenic trioxide dust that were emitted from the roaster stack spread in the region, contaminating local soils and lakes. The extent of this regional surface contamination is still being studied.

Here is a video that further explores the topic:


Bissen, M., Frimmel, F. H. (2003). Arsenic—a Review. Part I: Occurenc, Toxicity, Speciation, Mobility. Acta Hydrochim. Hydrobiol., 37(1). 9-18.

Indian and Northern Affairs Canada (INAC) (2007). Giant mine remediation plan. Report of the Giant mine remediation team-Department of Indian Affairs and Northern Development as submitted to the Mackenzie Valley Land and Water Board (MVLWB).

Wrye, L. (2008) Distinguishing between natural and anthropogenic sources of arsenic in soils from the Giant Mine, Northwest Territories, and the North Brookfield Mine, Nova Scotia. M.Sc.Thesis, Queen’s University, Kingston, ON.

Sunday, September 7, 2014

Silver mining in Bolivia

After a long period of silence here are some new insights, now on the world of mining in Bolivia, and especially in Potosi.

A bit of history

The silver deposits of Cerro Rico de Potosi ("Rich Mountain of Potosi") were first discovered in 1545 and would prove to be the single greatest silver deposits ever mined, producing more than 56,000 tons of silver (and 100,000 tons of tin) for over four and a half centuries.

There are many fabulous stories about the discovery of the deposit, one of which involves the intervention of a pre-Columbian divinity guarding against any non-Spanish exploration efforts. But the truth is much more likely to be wedded to serendipity than anything else. But between 1550 and 1800, Potosi alone contributed an estimated one third of the entire world’s silver production, all of it going directly in the Spanish Crown’s budget, minted as the Peso de Ocho, or Spanish dollar. 

However, throughout the 1500s and 1600s, the Spanish Crown (notably Charles V and Felipe II) was caught up in an endless series of religious and ideological wars against as many European powers as it could find (mainly Holland, England, France, the Ottomans, Lutherans, Calvinists, Muslims, any and all non-Catholics). Wars are fought on credit, and Spain borrowed immense sums of money from banks throughout Europe. Thus, over the centuries Spain's wars (and loans) became a mechanism for the redistribution of silver throughout Europe, paying for much of the Renaissance, which was in full bloom in these days.

And Europeans had an insatiable need for exotic goods, silk ans spices among many others. Most of these goods ultimately came from China (via the age old silk road), which happily traded all it could in return for silver. Of course Spanish merchants, sailors and daredevils capitalized on this opportunity and established the first cross-Pacific trade route, trading silver from the Americas directly to China (much to the Crown's displeasure). 

In other words, the Spanish Peso de Ocho was the first truly globally traded commodity, traded on all continents for centuries. It was so ubiquitous that it established itself as the standard international currency. Up until the mid-late 1800s, the USA, Canada, Japan and most South-American countries defined the value of their currencies on the Spanish dollar. Thence, Potosi was the single largest vector behind this spectacular global financial integration. One might call this globalization 1.0, long predating current globalization.

Potosi was so profoundly important in producing the World's wealth, and maintaining an established balance of economic power that I am often tempted to compare it with a country in the likes of a Saudi Arabia, or Kuwait, today. Their  mineral extraction is so important to the world that nothing would be allowed to inhibit their continued operations.

On mining methods

The debate of Valladolid (1550-1551) having condoned forced labour in the New World, Spaniards were very effective at re-establishing the Inca mita system of taxation in kind, into a system of slavery in all but name. Thence it was Quechuan aborigines that worked inside the notoriously dangerous mines in Cerro Rico and processed the ore in the ingenios of Potosi.

While mine workers were technically free men, mitayos owed the Crown years of their lives in the form of labour. In return for their extremely hard work they would enjoy the benefits of having a saved soul (through forced Catholic conversions and education), a trinket stipend, and the satisfaction of being part of the world’s largest empire.

In effect, as with all other stories of mining in Colonial Americas, the mining of Cerro Rico de Potosi is a long, tragic tale of aboriginal peoples (namely Quechuans) being worked to death by extremely unsafe conditions for little or no benefits. 

A total lack of mine engineering efforts, pervasive metal dust in the air, reckless use of explosives, poor equipment all add up to providing extremely dangerous working conditions. Countless people have died inside the mines, trapped in shafts after a rockfall. Yet certainly more have died prematurely from the long term effect of breathing heavily laden metal and silica dust in the mine shaft air.

On ore processing
Immediately after the discovery of the ore deposit the Spaniards established the city of Potosi. For the first few decades native silver was being mined and smelted using the Quechan huyaras (a wind-drafted kiln). It was operated by simply lighting up a hot, wind-enhanced fire in the bottom portion of the huyaras, and placing the ore in the top part. Quickly, the native silver would just melt out and could be made smeltered in situ. 

In those days, silver accounted for an estimated 25 wt.% of veins, making direct ore smelting viable. But by 1574, as native silver deposits were exhausted, disseminated silver was mined and processed using mercury amalgamation. Thus ingenios became an institution for the next three and a half centuries. 

Ingenios processed ore in ways very similar to the way artisanal gold miners work today, as discussed in previous posts, except on a more industrial scale. They required mechanical energy to power their stamp mills and crush the ore. Therefore the Spaniards built dozens of dams high up in the mountains above Potosi to capture and store water. They also dug a long river bed to channel the water from these dams into an artificial river running through town. Thence all ingenios and their water wheels were built along this river. 

A painting of Potosi from the 1700s

Highlighted are the dams and the ingenios along the river

But more than water, ingenios needed mercury. Large quantities of it. Mercury was essential in separating out the silver from the gangue (mine waste). Unsurprisingly, the ingenio workers, those who were the most exposed to mercury in their labour, were always aboriginal peoples.

After being crushed, the ore was sifted, then mixed with mercury, water and various chemical blends as catalysts in a large stone tub (cajón), and then spread out on a large patio. To promote efficient mixing and silver amalgamation, plant workers would march systematically along the patio and through the sludge, barefooted and often up to their knees or thighs, mixing the slurry with a shovel. This is the process during which mill workers would be exposed to direct skin contact with elemental mercury (Hg0).

Afterwards, the slurry would be brought to sluice boxes (lavadores) along the river to separate the sediments from silver-mercury amalgam. Though much of the amalgam would be recovered, invariably large amounts of mercury would mix with the sediments as small droplets and get washed away in the river as part of mine waste product. Mercury contained in these sediments would typically turn into methylmercury (MeHg) and accumulate in the food chain lower down the river basin (down hundreds of kilometers). 

An ingenio in the foreground with Cerro Rico in the background

The mercury recovered in the lavadores was then loaded into large cloth cylinders where it was compressed and repeatedly swatted with paddles in an effort to recapture any unbound mercury. The enriched amalgam product would contain one third silver and two thirds mercury, and would be brought into a ceramic mold (piña) and heated up for hours until the mercury volatilized and left behind a shiny sponge made up of about 70 wt.% silver. This process was by far the most important and direct pathway of exposure to elemental mercury the populations of Potosi were subjected to. Mercury vapour would escape in the atmosphere through the porous ceramic retorts and drift throughout the community for all to breathe. Meanwhile, the remaining silver sponge would later be smelted into ingots at high temperatures to eliminate any remaining impurities and to ease transport and accounting to the metropolis.

As soon as mercury amalgamation was adopted Potosi became the single largest consumer of mercury in the world, burning through an average of 130 metric tons per year, adding up to the release of over 39,000 tons of mercury in the environment throughout three centuries. Furthermore, to properly account for all mercury pollution from Potosi, one needs to consider its corollary: Huancavelica, a cinnabar mine in Peru which was effectively Potosi’s sole source of mercury and an equally dizzying source of pollution, without which virtually no silver could have been extracted from Cerro Rico. 

On Mercury pollution

Mercury is the most powerful neurotoxin in the world, and thus always raise particular concerns when humans are exposed. The physical symptoms mercury poisoning include tremors, pallidity, kidney failure, gingivitis, anemia, difficulty speaking, and loss of muscular control. Such symptoms are often in concert with neuropsychological effects such as personality changes, irascibility, impatience, hypercriticism, hallucinations, excessive shyness or suicidal tendency, shyness, depression, anxiety, loss of memory, obsessive–compulsive disorders, problems concentrating and impaired decision making.

For Potosi residents, the predominant form of mercury exposure came from breathing pervasive elemental mercury vapour in the air, coming from the burning of amalgam. Recent studies have modeled what mercury vapour concentrations might have been like throughout the city during the ingenios centuries.

Estimated long term ambient air mercury concentrations for Potosí and comparison with USEPA Reference Concentration (RfC of 0.3 µg/m³). Assuming a 20ft. stack height, stable air conditions. Mercury mass emissions based on historical records of mercury imports into Potosi during this year. Location of soil sample sites A B and C are transects of modern mercury soil measurements (Hagan et al., 2011).

Because ingenios were all water-powered, the ingenios were established along the ribera de los ingenios canal, and thus all the mercury emission sources were laid out in this axial geographical pattern.

The results show that even in the low production years, atmospheric mercury concentrations were virtually always above chronic exposure levels, across the entire city. Mercury concentrations were several orders of magnitude above chronic levels within 100m of the canal, approaching permanently acute levels. Given these values, it seems most likely that the mercury vapour concentrations inside the burning chambers of the ingenios must have been well above the acute exposure range, on a continuous level. Ingenio workers (always aborigines) were exposed to such concentrations on a daily basis.

Studied also looked into the mercury concentrations in modern Potosi soils, showing a very clear correlation between modeled atmospheric levels and deposition patterns. They also compared these modern soil values to those of historical cinnabar mine tailings (from elsewhere in the world), showing that the soils closest to the river have mercury concentrations that rival those of mercury mine wastes.

Comparison between measured soil mercury concentrations in present-day Potosí and historical air concentrations of mercury estimated by modeling emissions from mills located along the river. The A-B-C transects locations are shown on the previous figure (Hagan et al., 2011).
Mercury contents in soils of Potosi, compared to some of the  world's most contaminated mine wastes (Almaden mine), also compared to background values (Hagan et al., 2011).

The dangerously high levels of mercury in Potosi soils is today the most important environmental legacy left by 350 years of ingenios' mercury amalgamationIt would take only but a slight disturbance in local soils (a guaranteed event for any type of construction work) to bring back toxic levels of mercury in the atmosphere. Airborne dust is sure to be enriched in mercury, that in a city known for its strong winds and arid climate.

Ruins of an ingenio in the outskirts of Potosi. The entire area around these ruins is being developed to residential areas, despite soils having very high mercury concentrations.

So many mitayos died on the job that to escape forced enrollment, countless communities deserted their villages and took refuge in very remote areas of the Andes. Those mitayos that did survive service were crippled by debilitating life-long mercury exposure symptoms. One needs to imagine how entire communities populated by people with pronounced psycho-pathological impairments such as hallucinations, excessive shyness or suicidal tendency, obsessive-compulsive disorder, etc., to understand how the social fabric of communities would have been severely eroded away over generations of colonialism.

Potosi today

Potosi's world strategic importance lasted until about 1850 when silver production started to decline significantly, and mercury amalgamation came to an end. Nevertheless, Cerro Rico is still being mined today, producing mostly tin but also small amounts of silver and zinc.

Mine workers are no longer mitayos. They work for pay and are organized in cooperatives. This is a very clear improvement upon colonial-era working conditions. Nevertheless, work in the mines still remains extremely dangerous. Many miners still die inside the mines every year from rock failure. In fact, Cerro Rico has been so hollowed out from 500 years of ceaseless mining that the mountain is starting to collapse in on itself. The oxidized cap can barely be mined anymore from a series of very recent collapses that caused a large sinkhole at the summit.

A sinkhole at the summit of Cerro Rico

Beyond rock failure, the shafts have never had any kind of ventilation. The air is often rich in metal and silica-laden dust. This inevitably causes very grave respiratory problems such as silicosis. Miners typically start working in the mines at about 15 years of age, and quit around 25-30. They seldom live to see their 50th birthday. 

Mine workers inside Cerro Rico 

Here is a very good video on modern working conditions in Cerro Rico:

While mining work in Potosi does not involve mercury anymore, there is still an overwhelming legacy of mercury pollution. The entire city of Potosi is built on soils that has mercury contamination levels comparable to those found in unremediated mercury mine tailings elsewhere in the world. It would take only but a slight disturbance in local soils (a guaranteed event for any type of construction work) to bring back toxic levels of mercury in the atmosphere. Airborne dust is sure to be enriched in mercury, that in a city known for its strong winds and arid climate. As a corollary to Potosi and a living example of the nature and level of the risk still existent today, many adobe houses in Huancavelica are built from local contaminated soils, such that people’s very habitations are still emitting mercury-laden dust, still putting the community at risk to this day

Potosi reminds us that the benefits of empire seldom serve those who carry their costs. It also shows us that the pernicious heritage of empire far outlives its very existence, and will still be carried by generations yet unborn.


Hagan, N., Robins, N.A., Hsu-Kim, H., Halabi, S., Morris, M., Woodall, G., Zhang, T., Bacon, A., Richter , D. and Vandenberg, J. (2011) 'Estimating historical atmospheric mercury concentrations from silver mining and their legacies in present-day surface soil in Potosí, Bolivia', Atmospheric Environment, vol. 45, p. 7619e7626.
Higueras, P., Llanos, W., Garcia, M.E., Millan, R. and Serrano, C. (2012) 'Mercury vapor emissions from the Ingenios in Potosí (Bolivia)', Journal of Geochemical Exploration, vol. 116, pp. 1-7.
Robins, N.A. (2011) Mercury, Mining, and Empire: the Human and Ecological cost of Colonial Silver Mining in the Andes, Boomington, IN: Indiana University Press.
Robins, N.A., Hagan, N., Halabi, S., Hsu-Kim, H., Espinoza Gonzales, R.D., Morris, M., Woodall, G., Richter, D., Heine, P., Zhang, T., Bacon, A. and Vandenberg, J. (2012) 'Estimations of historical atmospheric mercury concentrations from mercury refining and present-day soil concentrations of total mercury in Huancavelica, Peru', Science of the Total Environment, vol. 426, pp. 146-154.

Tuesday, March 25, 2014

A summary

Hi all,


I compiled a quick resume of some of my first 6 months in Senegal, which is usually the time with the steepest learning curve.
Some of the themes I have already discussed earlier, but I hope this narrative will prove both informative about West African realities, and can shed some light on the 1st hand experience of life in rural Senegal.
I don't know what it's worth but here it is. This is Martin's take on the Peace Corps in Senegal.

Also, I'll be talking a lot more about mercury, arsenic, mining and pollution later on since this topic is what I'm dedicating my Master's degree on.


Success consists of going from failure to failure without loss of enthusiasm.

--Winston Churchill

As a first impression, Senegal does not have much to boast for. Stepping out of the airplane in Dakar, one will smell the pungent stench of diesel exhaust, see and inevitably step, stumble on the ubiquitous debris on the ground: loose cobble, broken asphalt, gravel, sand, dust, dirt, soot, grime, slime, mire, muck and gunk that constitute the décor of this modern, rapidly growing city of the third world. As for what the chemical make of this superlative anointment may be, no one knows, nor does anybody really want to know; but the input material tends to be easily recognizable as plastic bags, plastic water bottles, plastic wrappers, paper wrappers, newspapers, diapers, tin cans, banana peels, mango peels and anything else one might expect to see in a tropical garbage bin. Now all this gets flattened, cut and chewed up by city traffic so that it’s just ripe for when the rains come and the sewage system (or lack thereof) overflows and floods entire neighbourhoods with black water, and binds the whole in a matrix of biohazard. Meet cholera, dysentery and typhoid.

As a second impression, Senegal has even less to offer. Walking through town one will be completely overwhelmed with aggressive (Wolof) taxi drivers calling you “mon ami,” grabbing on to your hand and/or luggage without your consent and demanding exorbitant fares. The cars will inevitably be a failing 30 year old French Peugeot beyond hope of repair, or rather, beyond hope of anybody caring to try and repair them. Then there is always the spectacularly disordered and frightful traffic that has become proverbial of third world cities. But what is really unique to Senegal are the swarms of kids coming around you at every intersections, holding on to an empty red tomato paste tin can, or an empty plastic yellow margarine bowl. These are talibe, students of a koranic school, performing their daily obligation of begging for food, money and sugar to give back to their marabout (teacher). Meet childhood slavery.
For parents, the daara (koranic school system) is a free alternative to the governmental French school system, the latter though technically free, still infers a cost through textbooks and modest entry fees. Therefore poor, or conservative, parents will send their kids to a marabout; and in return kids owe absolute obedience to him. This means that they don’t go back home to see their parents, ever. They sleep, eat, live in ruined compounds too abhorrent even for stray dogs. They’ll spend one half of the day reciting surats (koranic verses) and various ancestral magic spells in a language they don’t understand, nor ever learn. The other half they spend drifting around town, singing prayers and begging for some food to survive, and money to avoid a severe thrashing by the marabout.
One such daara burned down one night in the outskirts of Dakar while I was a volunteer. The marabout had locked the doors of the compound from the outside, as is customary. A dozen kids died, others severely burnt. The event was thought as no more than an unfortunate accident.
This koranic school system is ubiquitous in Senegal. It is considered perfectly acceptable. Parents send their kids all the way from far Guinea to powerful marabouts and famous daaras, with the idea that religious education is a good thing. What is there to say to a society that commends such a system of abuse? This reality is one of the main reasons I hold such evermore disagreeable feelings towards Senegal. There is a level of woe that has no justification, and a level of complacency that cannot be excused. I would see kids as young as 5 years old wearing nothing but torn rags, shoeless, filthy as can be, often hurt, always malnourished, begging for a few handfuls of rice for survival. These are daily sights in urban Senegal, part of the routine, just like traffic, or the prayer calls of minarets. If I have ever seen wretchedness, I have seen it in the empty stare of a wandering talibe, reciting koranic verses, hoping they will feed him.


My first order of business after all the ceremonial welcomes in village was setting up a tree nursery. We had been taught how to build a school vegetable garden and were expected to work on such a project. The ubiquitous presence of roaming animals in Senegal, especially goats, makes any gardening effort hopeless without a fence. However, fences are very hard to come by in rural Senegal. The best long term option is certainly to plant a live fence, made of thick thorny species, forming a living wall around a protected area. So I went along, planting dozens of thorny bushes in a tree nursery. I then transplanted them in the village elementary school perimeter at the start of rainy season. But it turns out, small trees are quite tasty to goats, and in order to start a live fence one first needs to protect the saplings for the first 2 or 3 years—hence one first needs a fence. Ironic, isn’t it? In the end I set up a makeshift woodstick fence that helped somewhat in protecting all the trees I’d out-planted. So everything was put in place for when school was to start again (after the rains, in the Fall) we could have some gardening lessons. Then came September and the teachers weren’t back from their holidays yet (teachers invariably are not originally from the village they work in). Nor did they show up in October, November, or December. It turned out the teachers weren’t being paid nationwide, so they all went on strike. But because teachers went on strike the education ministry withheld salaries even more. Here was irony again. This entire situation was new to me, though I was told it happened cyclically. Therefore, school that year only started in mid-January. Schedules were rushed and few students or teachers had the time or desire to do much gardening. So much for that project that year! Here was my first lesson in the effects of severe corruption.

One small work project I got involved with was helping out with two summer camps. This had me going to various villages of Pulaar-land to help teach math, French, lead challenge courses and teach teenagers such life skills as how to use a condom. This was really cool as it involved kids from really poor and remote regions, for whom this was the single greatest experience of their lives, so they were extremely enthusiastic about everything. In a general sense, I have found Senegalese kids to be some of the most fun there is to be had in that country. All this also involved reuniting with other PCVs from all over that I would seldom get to see otherwise. I remember these events as the time during which I enjoyed Senegal—and myself—the most. The only downside for me was that I had conjunctivitis for a few weeks, which is a thoroughly annoying virus to catch. Thankfully this was to be one of only three I would ever catch in Senegal. I was lucky.

The major project I had started on was pump repair trainings. The main issue for Kondokhou villagers was the difficulty of access to drinking water. The only viable water sources were two hand pumps a kilometre outside the village. They were overstressed in their use and when they broke down, no one knew how to repair them, save for a government team in the regional capital who extorted outrageous fees, crippling for a village. I realized that the pumps were of very simple design, meant to be easily fixed with simple tools. So I found documents on how to repair these pumps, taught myself, went to Dakar—700km away—to buy the tools (there’s no proper hardware store anywhere else in the country!), formed a village repair team and taught them how to fix the pumps. It worked well, that is until the pump repair team started asking for money for spare parts and modest salary. Usually, emergency pump repair money was taken out of the Sodefitex account (a village bank account created from the fair trade label on local cotton production—essentially a tax on village cotton farmers). Cotton farmers however refused to have to bear alone the cost of a universal necessity. So we tried to levy money from compound to compound, based on a per-person quota. The answer we often had was “I don’t have the money right now, come back tomorrow.” This, mind you, is viable excuse in most of West Africa, where common peace and harmony may not be broken over money matters. We thought of asking for small coins for every person taking water per day, but there is a very serious lack of small change in Senegal, and coins are always hard to come by, making small transactions very difficult. That and such a system would require someone sitting at the pumps all day, doing that job. No one was willing to assume such a chore. A subscription system would similarly involve an employee, with some accounting skills that too few have in village (most never get passed grade 5 education). On top of all that, there were big trust issues as precedents of village account money disappearing existed, and any one taking on such a job risked being accused of misappropriation. We were in a bind indeed!
What such a situation breeds can be best exemplified when a government program came to drill a new borehole in the village 4 months into my service, and built a brand new expensive hand pump. Great news! The two other pumps had a constant 20 to 30 minute wait lineup, so this would greatly relieve the situation. However the village chief decided that the new pump was to stay locked until the village had solved the pump repair money situation. By the time I left village, two years later, the brand new pump was still locked! It had been used once for two weeks, then locked up again. Here was my first lesson in the effects of severe societal dysfunctionality.

Another smaller project was thrust upon me early on in my service. Villagers approached me a few weeks after arriving in village hoping I might be able to solve the latest village drama. World Vision had recently arrived asking for the community contribution for the health hut they had just built in the village. Of course, the village health account was completely empty. Everybody openly suspected the village health worker to have stolen the money. So they asked me, the toubab (white person), see if I couldn’t “find” money that would cover their needs. I did my investigation, came to realize there hasn’t been money in that account for at least 5 years. There there was no paper trail (again, the health relay has 5th grade education and never learned bookkeeping) and no one even remembered the last time there ever was money in the box at all! Mind you, no one ever thought it anything much out of the common way, and no inquiry was ever proposed until World Vision came asking for their due, when everybody’s backs were against the wall. We held a big village meeting. I told everybody that while I couldn’t make accusations, it was obvious the system currently in place was broken. They agreed to form a committee with a supervisor who would oversee everything, leave a paper trail and report to the village chief on the money status. The system was fairly functional—and most importantly profitable by the time I left village. I was eventually entrusted with the village contribution to World Vision (then again, they couldn’t trust anybody with money within the village), and I bought drugs and supplies for the hut. However, the rooftop of the health hut fell apart during the rainy season (there are always high winds associated with rainstorms)—coincidently, the peak of malaria season, rendering the hut unusable when most needed. The Catholic Relief Services had promised they would fix it but we never saw that happen. Here was my first experience with severe incompetence.

These stories point to some of the major themes that permeate a Senegalese reality that tourists won’t see. First you have systemic societal dysfunction, and a level of complacency about it that is crippling. The system is broken and no one thinks of doing anything about it. A lot of that has to do with the lack of basic education, even literacy, of locals, explaining the lack of efforts such as simple bookkeeping. Second is the cultural approach with money matters which breeds distrust, and discourages common accounts. People are poor, money is money, and accounts (i.e. cash hidden in a sock, under the bed) get mixed depending on daily needs and never get refilled. A lack of understanding of entity ownership and binding obligations explain that corrupt actions are seldom thought of as such and are always excused. Third there are the obvious problems of remoteness and poverty. Stuff is expensive, it’s far and there’s no real way to access it. Roads are terrible, transportation is god awful and people can’t really pay for it all anyways, making it very hard if not impossible for a person to invest in a farm, a house or a business. Lastly is the persistent failure of government infrastructure and aid organizations to provide services appropriate to needs. Systemic corruption mixed with various levels of incompetence goes a long way in explaining this fact. All of this adds up to creating a very real sense of lethargy about anything development-related. Sooner or later a Peace Corps Volunteer realizes that despite one’s best efforts, mediocrity and disappointment is the very best one might hope for. The worst, of course, being a project’s utter failure, and aggravating the local feeling of dependence on foreign aid.

By the sixth month of my service I had lived enough to understand these realities and what they would entail for the rest of my life in Senegal. With such a learned perspective, prospects started to feel remarkably bleak. I had already started and implemented interesting projects. I had done all I could to set them up in a sustainable manner, that they could last past my service. Yet, as soon as I disengaged and let the villagers use their new learned tools for themselves, dysfunctionality still prevailed. And to my dismay, it was never the “hard,” technical skills that let down, but village politics and money matters. I learned to make peace with that by reminding myself that a Senegalese problem will always have a Senegalese solution. 

Such a conclusion may sound bleak indeed. The simple truth is that it's a tough world out there. But more than diseases, dysfunction, and all the pains that come with living in West Africa, the real challenge of this all is in learning how to make peace with these hard facts. Yet, therein lies the redeeming value of the experience. To learn how to create for oneself a measure of fulfillment and happiness in such a difficult environment is to learn to deal with any and all things that are thrown at you, no matter what, and to squeeze all the worth out of it. I believe that such a lesson is perhaps one of the most valuable and meaningful the Peace Corps can offer their volunteers, and returned volunteers.