Going for gold: environmental impacts of illegal gold mining in the Amazon

  • By Adam Ashby

Examining the environmental and social impacts of artisanal and small-scale gold mining in Madre de Dios, Peru


Artisanal and small-scale gold mining (ASGM) continues to pose significant biodiversity issues to the Amazon region. It is estimated the number of operating mines throughout the region is growing and will continue as the hunger for gold increases. A surge in the price of gold in the late 2000s has magnified this issue and will continue to put pressure on Amazon ecological systems without holistic mine planning, robust regulatory frameworks, and sustainable environmental management practices.

This issue is amplified when these clandestine operations close without meeting appropriate requirements. Whilst the environmental footprint of these operations is generally small, the overall impacts are significant, and range from loss of biodiversity through to water quality issues. This is of concern when mercury is used to extract gold. The methods used to extract gold are generally crude, archaic and often undertaken without any regulatory assessment or approval, which has the potential of polarising local communities, and resulting is systemic environmental issues.

This article reviews the literature on the topic of ASGM mining in the Madre de Dios region of Peru, and specifically its environmental impacts and the attempts at control, management and closure of ASGM operations through government policy and practices. The review encompasses peer-reviewed papers, as well as white papers and ‘grey’ literature of industry and government.


The southern Peruvian Amazon region of Madre de Dios is internationally recognised as one of the most biologically rich regions on Earth (Asner and Tupayachi, 2017; Roman-Danobeytia et al, 2015). Under Peruvian Law, the region is viewed as the ‘Capital of Biodiversity’ (Joshi et al 2015; Swenson et al, 2011). The region also provides numerous ecosystem services, ecotourism pursuits and broad cultural and spiritual connections for indigenous communities that inhabit these areas (Scullion et al, 2014). 

Notwithstanding the biological diversity and strong environmental and cultural values of Madre de Dios, these often pristine environments are under threat from operations known as artisanal and small-scale gold mining (ASGM) which is defined as ‘all small, medium, large, informal, legal and illegal miners who use rudimentary processes to extract gold from secondary and primary ore bodies’ (Veiga and Hinton, 2002). Paradoxically, artisanal gold mining dates to times where ‘pick and shovel’ were once used to extract gold. However, it has since evolved whereby mechanised equipment is now used to explore for and extract gold (Owusu et al, 2017).

While the term ASGM refers to both licit and illicit mining activity (depending on region and context), it typically results in rainforest degradation, loss of biodiversity and water quality issues; so, the activity is intrinsically illegal, is often transient, and therefore a challenge to monitor using contemporary regulatory and compliance tools (Elmes et al, 2014).

Operators target the gold-bearing ore, often using unsophisticated equipment and clandestine methods; for instance, vegetation is usually cleared and removed by hand then high-pressure pumps are used to remove topsoil, ore, sand and clay (Elmes et al, 2014).

The material is then fed into a sluice box, collecting the gold particles, with the waste material flowing into a pit or discharged into the wider forest environment (Macdonald et al, 2014; Peterson and Heemskerk, 2001).

The introduction of mercury, a toxic substance used as an amalgam to liberate the gold during the processing, results in human illness, soil and water contamination and negative impacts on fish stocks (Owusu-Nimo et al, 2018; Elmes et al, 2014).

Clandestine sluice operating within the Amazon River. Source: Forest Service Alaska Region, USDA. Photographer: Steve Kessler. Used under Creative Commons CC BY 2.0.

The proliferation of ASGM gold operations in Madre de Dios is directly linked to the rapid increase of the global price of gold (Figure 1). The most notable increase in price of gold was in 2001, where the price skyrocketed from $400 USD to $1600 USD. The price of gold has steadily increased due to the global recession in 2008, among other factors. Nevertheless, it peaked in 2011 to over $1800 USD (Asner and Tupayachi, 2017; Papworth et al, 2017; Asner et al, 2013; Swenson et al, 2011).

Figure 1. Graph showing spot price of gold in shown in US dollars. Note spike in price in 2012 (adapted from Wold Gold Council, 2018).

Peruvian mine closure legislation

The Peruvian government has enacted comprehensive mine closure legislation, for instance Ley Nº 28090 – Ley Que Regula El Cierre De Minas or the Law that regulates the closure of mines in October 2003 (Garcia, 2008).

Comparatively speaking, the overarching closure principles and framework for large-scale mining operations are to ensure that at closure, mining operations are closed so that environmental impacts (such as stability and pollution) are mitigated, and that rehabilitation is undertaken in a sustainable manner – resulting in positive environmental impacts post-closure. More importantly, issues around human health and safety are paramount in relation to mine closure (Nichols et al, 2015).

But the closure requirements of ASGM operations are less stringent – or non-existent, as noted in a report commissioned by the United Nations Environment Programme (UNEP, 2012). This report highlighted that the requirements of mine closure for artisanal miners is contemporary, nuanced and ‘based on a post-closure assessment.’ Furthermore, the report noted that there is an absence in the requirement and guidance material or strategies in relation to simplified rehabilitation plans or guidelines that reduce costs of rehabilitation.  

According to Swenson et al (2011), Madre de Dios has the highest number of unapproved (illicit) mining ASGM operations in Peru. This issue is largely driven by low governance, poor regulation, poor enforcement and little incentive by ASGM miners to obtain the necessary environmental approvals. This issue is of paramount importance and needs to be addressed as it was estimated that in 2015 there are more than 500 000 illegal gold miners in operation in the Amazon region (Román-Dañobeytia et al, 2015).


The cryptic nature and sheer spatial distribution of illicit ASGM operations in Madre de Dios presents a monolithic challenge for governments to regulate (Hilson and Van Der Vosrt, 2002). Modern tools such as sophisticated airborne high-resolution satellite monitoring platforms are deployed by aircraft to determine the scope and extent of this issue as noted in previous studies (Asner et al, 2013; Joshi et al, 2015). Asner et al (2013) note that these tools have a high level of accuracy and are efficient at detecting such clandestine activities, which are often located out of field of view from areas such as roads and rivers and are not easily accessible by authorities. 

The drivers of illicit ASGM are complex and varied to say the least, but it is fundamentally clear that the increase in the price of gold over the last decade has triggered the proliferation in such operations in the region of Madre de Dios (Anser and Tupaychi, 2017; Lobo et al 2017). ASGM miners are often from inherently poor backgrounds both in terms remuneration and educational contexts; nevertheless, the industry provides employment and income for many millions of people. Moreover, approximately 10-15 per cent of the global production of gold (Paterson and Heemskerk, 2001; Miserendino et al, 2013; Elems et al, 2014; Bansah et al, 2016). The estimated population of miners in Peru is shown in Figure 2.

Figure 2. Map showing estimated global population of artisanal and small-scale mining (adapted from http://artisanalmining.org). Click for larger image.

To combat the social and environmental issues of ASGM operations, government agencies conduct raids whereby Peruvian officials dismantle equipment and infrastructures, thereby rendering the operations inoperable (Anser and Tupaychi, 2017). Other initiatives used to address issues associated with ASGM practises include strategies to manage mine waste in the form of tailings, specifically the safe storage period of 15 years. The overall aim of these measures is to reduce and mitigate water pollution because of poor tailings and waste management whereby in some instance, tailings frequently laden with mercury and cyanide are directly discharged into river systems without robust control mechanisms – thus resulting in widespread social and environmental implications both temporally and spatially (Miserendino et al, 2013).

A large body of research exists around mine closure for large scale mining operations in ‘grey’ and ‘white’ literature and peer-reviewed material. However, peer-reviewed material in relation to mine closure of ASGM operations is somewhat scant, particularly the closure of operations in Madre de Dios. The lack of such material is alarming and highlights the need for research and action by government, non-government agencies and other key stakeholders that are affected by such mining activities.  

Paradoxically, the Peruvian government has set aside areas whereby ASGM can be lawfully undertaken; the area is known as the ‘Government Mining Corridor’ (see Gardner, 2012). The aim of creating this area was to protect the biodiversity and cultural values of the region; nonetheless, many miners operated outside the designated area, resulting in outrage from communities. The area has been previously known as a hotspot not only for violence, but also mercury poisoning and health-related issues to many people within the mining population, including women and children who are most susceptible to mercury poisoning (Gardner, 2012; Miserendino et al, 2013; Zolnikov and Ortiz, 2018).

The Peruvian government has subsequently attempted to implement legislation to protect the rich biodiversity of the Amazonian region. Throughout the research for this paper, we found limited evidence that any legislation has or ever will be enacted in the future to enforce strict mine compliance on such clandestine operations, which largely operate outside the realm of any such regulatory frameworks. While every mine in Madre de Dios will eventually close, there is a strong push to continue operating while the price of gold continues to remain buoyant and provides income for millions of miners and much needed revenue for Peru and its people.


The environmental impacts of ASGM are well documented and the reported high price of gold will continue to spur on illegal activities, which paradoxically provide much needed income for many millions of people, and more importantly a boost the Peruvian economy. However, such short-term wealth brings with it many challengers for the regulatory agencies of Peru whom are desperately examining strategies to curve this widespread damage associated with ASGM activities within the region of Madre de Dios.

The introduction of measures such as mine closure guidelines solely geared at ASGM operations would assist in combating the closure liabilities and would be a step in the right direction, at least to provide some framework that is largely missing from the current ASGM process. The legislative framework is there; what is needed now is the political will. However, this can only occur with full and open stakeholder and community engagement.


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